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  • 1.
    Elo, Robin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Heinrichs, Jannica
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Surface texturing to promote formation of protective tribofilms on combustion engine valves2018Inngår i: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 232, nr 1, s. 54-61Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In a combustion engine, the valve system controls the flow of gases in to and out of the combustion chamber.The contacting surfaces experience a harsh tribological situation with high temperatures, high speed impacts, corrosiveenvironment and high closing forces causing micro sliding in the interface. The components have to endure in the rangeof hundreds of millions to a billion operational cycles, resulting in extreme demands on low wear rate. Such low wearrates can be accomplished by the protective action from tribofilms forming from oil residues, avoiding a pure metal-tometalcontact. Such tribofilms are found on well-functioning engine valves from a variety of engines, but some stationarygas engines experience problems with wear occurring seemingly randomly at normal running conditions. For somereason, the tribofilm has not protected the surfaces sufficiently, causing wear. One way to combat the random behaviourcould be to promote robust function of the protective tribofilms by texturing the valve sealing surfaces to improve thecapture and storage of oil residues. By stabilising the supply in this way, the damage from periods with low access totribofilm forming material could be reduced. The present work demonstrates that turning of the valve seat inserts,creating valleys perpendicular to the sliding motion, can be developed into a useful solution. The amount and localisationof tribofilms became more predictable and stable than without the texture, leading to reduced component wear. Thevalleys should not be too wide, since this increased the amount of exposed metal if the tribofilm flaked off. When havingthe same width, the deeper valleys showed less flaking off of the tribofilm.

  • 2.
    Elo, Robin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Heinrichs, Jannica
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Wear protective capacity of tribofilms formed on combustion engine valves with different surface textures2017Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 376-377, s. 1429-1436Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The valve system controls the flow of gases into and out of the cylinders of combustion engines. As the combustion chamber is repeatedly filled with air and emptied from combustion residues, the contacting surfaces of the valve and valve seat insert (VSI) are exposed to high temperatures, high speed impacts, corrosive environment and high closing forces. Since the expected wear life of the components is hundreds of millions of operational cycles, the wear rate has to be extremely low. Previous studies have shown that this is accomplished by the continual formation of protective tribofilms on the surfaces, formed from oil additive residues. For some stationary gas engines, seemingly random occurrence of severe wear, i.e. without correlation to special running conditions, calls for an improved understanding of the wear protective abilities of these tribofilms. Further, the potential of making the protection more robust by using simple textures on sealing surfaces is investigated. Real valves and VSI's were therefore run in a dedicated test rig, previously shown capable of forming tribofilms similar to those found in real engine valves. Two surface textures, turned or ground, were tested. After a running in phase where fully covering tribofilms were formed, the tests were continued without adding the oil residues needed for replenishing the tribofilm. The flow of oil residues was either completely stopped or only intermittently open. The resulting wear was monitored during testing and after finishing the tests remaining tribofilms were analysed with SEM and EDS. The severity of the wear was graded and the presence of tribofilm and localization of wear was correlated. The endurance of the tribofilms was surprisingly high for both textures. Typically the tribofilms exhibited better wear resistance than the underlying metals. Once fully formed, the tribofilms can therefore endure for a long time without addition of new tribofilm forming material. Both textures showed the first sign of wear after roughly the same time and then followed the same progression, when the flow of oil residues was cut. With the intermittent oil residue supply, both textures performed even better. Especially the turned texture showed only slow, mild wear.

  • 3.
    Gerth, Julia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Collin, Marianne
    Sandvik Machining Solutions, Stockholm.
    Andersson, Gunilla
    Sandvik Machining Solutions, Stockholm.
    Nordh, Lars-Göran
    Uddeholms AB, Hagfors.
    Heinrichs, Jannica
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Wiklund, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Adhesion phenomena in the secondary shear zone in turning of austenitic stainless steel and carbon steel2012Konferansepaper (Annet vitenskapelig)
  • 4.
    Gerth, Julia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Gustavsson, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Collin, Marianne
    Sandvik Machining Solutions, Stockholm.
    Gunilla, Andersson
    Sandvik Machining Solutions, Stockholm.
    Lars-Göran, Nordh
    Uddeholms AB, Hagfors.
    Heinrichs, Jannica
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Wiklund, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Adhesion phenomena in the secondary shear zone in turning of austenitic stainless steel and carbon steel2014Inngår i: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 214, nr 8, s. 1467-1481Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper aims to increase the understanding of the adhesion between chip and tool rake face by studying the initial material transfer to the tool during orthogonal machining at 150 m/min. Two types of work material were tested, an austenitic stainless steel, 316L, and a carbon steel, UHB 11. The tools used were cemented carbide inserts coated with hard ceramic coatings. Two different CVD coatings, TiN and Al2O3, produced with two different surface roughnesses, polished and rough, were tested. The influences of both tool surface topography and chemistry on the adhesion phenomena in the secondary shear zone were thus evaluated. Extensive surface analyses of the inserts after cutting were made using techniques such as Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS), and Transmission Electron Microscopy (TEM). As expected, cutting in the stainless steel resulted in a higher amount of adhered material, compared to cutting in the carbon steel. Remnants of built-up layers were found on the surfaces of the 316L chips but not on the UHB 11 chips. Moreover, it was shown that for both materials the tool roughness had a profound effect, with the rougher surfaces comprising much higher amounts of adhered material than the polished ones. Non-metallic inclusions from both types of workpiece steels accumulate in the high temperature area on the inserts. The general tendency was that higher amounts of transferred material were found on the TiN coating than on the Al2O3 coating after cutting.

  • 5.
    Gerth, Julia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Heinrichs, Jannica
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Nyberg, Harald
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Larsson, Mats
    Primateria AB, Uppsala.
    Wiklund, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Evaluation of an intermittent sliding test for reproducing work material transfer in milling operations2012Inngår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 52, s. 153-160Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    TiN coated HSS test cylinders from an intermittent sliding test were compared with TiN coated HSS milling inserts from a single insert milling test. A 20NiCrMo2 case hardening steel was used as counter material and work material in the two tests. HSS test cylinders, coated with AlCrN, TiAlN and Al2O3, were also tested in the intermittent sliding test and evaluated with regard to material adhesion. Two distinctly different tribofilms were formed on test cylinders as well as on cutting inserts. One consisting of Mn, Si, Al and O and one consisting of Fe, Mn, Cr, Si and O. The transferred material was similar in appearance and composition, both when comparing the two test methods and when comparing the different tool coatings.

  • 6.
    Heinrichs, Jannica
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    On Transfer of Work Material to Tools2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Bulk forming and cutting are widely used to shape metals in industrial production. Bulk forming is characterized by large strains, extensive plastic deformation and large surface expansions. Cutting is characterized by high speeds, high pressures and high temperatures. The prevailing conditions during these processes lead to transfer of work material to tools. In bulk forming this is a significant problem. The transferred work material is hardened and becomes harder than the work material, causing galling. This leads to high friction and high forming forces, bad surface finish of the formed products and significant difficulties to produce complicated geometries. In cutting, transfer of work material can be desired for protection of the tool surface. However, the transfer film has to be of the correct type to provide a stable and predictive behaviour during operation.

    In this thesis the influence from tool material and surface treatment on work material transfer has been studied for both applications, with the use of simplified laboratory test methods followed by extensive surface studies. Both the tendency to, appearance of and chemical composition of work material transfer is evaluated. The results are compared with real industrial examples, to ensure that the correct mechanisms are mimicked.

    In forming, the problems arise when poor lubrication prevails, due to high forming forces or large surface expansions. The transfer of work material can then be avoided with the use of a galling resistant coating, offering low adhesion. However, the coating has to be as smooth as possible, to avoid activation of the work material and subsequent transfer.

    In cutting, the desired transfer film can be obtained by choosing the correct cutting parameters. The geometry and material of the fabricated component is often predetermined, setting the general cutting conditions, but the cutting speed influences the formation of the transfer film. Too low speed or too high speed leads to an unstable cutting process and poor surface finish of the piece. The speed intervals for each mechanism are partly determined by the tool material and thus by the tool coating.

    Delarbeid
    1. Laboratory test simulation of galling in cold forming of aluminium
    Åpne denne publikasjonen i ny fane eller vindu >>Laboratory test simulation of galling in cold forming of aluminium
    2009 (engelsk)Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 267, nr 12, s. 2278-2286Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Cold forming of aluminium is a group of very efficient methods, which are successfully used in a number of industrial applications. Two of the major factors limiting the tool life and restricting the shapes and sizes possible to produce, are galling, i.e. transfer of work material to the tool surface, and high stresses occurring when forming complex shapes. Both phenomena are closely related to the friction and adhesion in the tool to workpiece interface.

    The present paper investigates the influence of several surface parameters to the tendency to galling. This is done by forming aluminium using tool steel in a geometrically simplified lab test. The test scans over a wide load interval while monitoring the coefficient of friction. The corresponding transfer of work material to the tool surface is studied in the SEM after testing. The test is focused on the initial tool contact and also on the number of contacts before a critical friction level is reached.

    The test set-up comprises two crossed cylinders in sliding contact, one made of tool steel and one of work material. Three commercial tool materials were included, each prepared to two surface finishes. The aluminium workpiece cylinders of AA6082 were prepared by two different pre-treatments, solid lubrication followed by soft annealing and pickling, respectively.

    The respective importance of the tool material, preparation of the tool surface finish and the aluminium surface pre-treatment are compared with respect to initial galling tendencies and friction stability. The practical implications for real forming applications are discussed.

    HSV kategori
    Forskningsprogram
    Materialvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-111808 (URN)10.1016/j.wear.2009.04.006 (DOI)000272810200017 ()
    Tilgjengelig fra: 2009-12-22 Laget: 2009-12-22 Sist oppdatert: 2017-12-12
    2. Laboratory test simulation of aluminium cold forming – influence from PVD tool coatings on the tendency to galling
    Åpne denne publikasjonen i ny fane eller vindu >>Laboratory test simulation of aluminium cold forming – influence from PVD tool coatings on the tendency to galling
    2010 (engelsk)Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 204, nr 21-22, s. 3606-3613Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Cold forming of aluminium is a group of very efficient methods used in a number of industrial applications. Two of the major factors limiting the tool life and restricting the complexity of the shapes produced, are galling, i.e. transfer of aluminium to the tool surface, which leads to problems in successive forming, and high stresses occurring when forming complex shapes. Both phenomena are closely related to friction and adhesion in the tool to workpiece interface. Earlier investigations have shown that aluminium is transferred to the tool steel surface regardless of the surface roughness of the tool. This has been proposed to be due to the hard native oxide on the soft aluminium leading to a mechanical gripping in the tool surface.The present paper investigates the influence of ceramic coatings on the tendency to galling. This is done by plastic forming of aluminium against coated tool steel rods in a lab test. The test scans over a wide load interval while monitoring the coefficient of friction. The transfer of work material to the tool is studied in the SEM. The test is focused on the friction level and on the number of contacts before a critical friction level is reached.The test set-up comprises two crossed cylinders in sliding contact, one made of coated tool material and the other of work material. Eight commercial coatings were included; DLC, TiAlN, TiN and TiCN as single layer or as multilayer combinations, with hardness values ranging from 800 HV to 3500. HV. All substrates were the same tool steel material (H13), prepared to two different surface finishes. The aluminium work piece cylinders of AA6082 were prepared by two different pre-treatments, soft-annealing followed by industrially used solid lubrication and pickling, respectively.The coating material, preparation of the tool surface finish and the aluminium surface pre-treatment all proved important with respect to galling tendencies and friction levels. Three of the DLC coatings showed very promising behaviour, also without lubricant, but surface roughness deteriorates the galling resistance. The other low-friction coatings tested neither improved the galling resistance nor reduced the friction significantly, compared to the uncoated tool steel.

    Emneord
    Aluminium alloy, Ceramic coating, Friction, Galling
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-134845 (URN)10.1016/j.surfcoat.2010.04.025 (DOI)000279696400036 ()
    Tilgjengelig fra: 2010-12-02 Laget: 2010-12-02 Sist oppdatert: 2017-12-12bibliografisk kontrollert
    3. Mechanisms of transfer of aluminium to PVD-coated forming tools
    Åpne denne publikasjonen i ny fane eller vindu >>Mechanisms of transfer of aluminium to PVD-coated forming tools
    2012 (engelsk)Inngår i: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 46, nr 3, s. 299-312Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Cold forging is a group of methods effectively used in a number of industrial applications to form aluminium. Tool life and complexity of the possible shapes are mainly restricted by galling; the uneven tool surfaces caused by lumps of transferred material lead to surface damage on successive parts formed and/or problems in successive forming operations, and high stresses occurring when forming complex shapes. Earlier investigations have shown that improved surface roughness of an uncoated steel tool decreases the amount of adhered aluminium on the tool, but does not decrease the friction in the long run. Testing has also shown that when using conventional forming tools it is very important to have sufficient lubrication to avoid galling. Addition of an optimized low-friction PVD-coating decreases the galling tendency and increases the tolerance to insufficient lubrication and lubricant film breakthrough, as long as the coating surface is smooth, whilst other similar coatings have little or no effect. The present article further investigates the mechanism behind the transfer of aluminium to the coatings. All coatings were found to be intact after testing, and so the differences were concluded to lie in the chemical properties of the coating and, if these are favourable, then in surface roughness on the micro scale.

    Emneord
    Galling, Friction mechanisms, Friction-reducing coatings, Aluminium
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot tribomaterial; Teknisk fysik med inriktning mot materialvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-167057 (URN)10.1007/s11249-012-9952-5 (DOI)000303876300009 ()
    Tilgjengelig fra: 2012-01-19 Laget: 2012-01-19 Sist oppdatert: 2017-12-08bibliografisk kontrollert
    4. Evaluation of TiB2 coatings in cold forming of aluminium
    Åpne denne publikasjonen i ny fane eller vindu >>Evaluation of TiB2 coatings in cold forming of aluminium
    2012 (engelsk)Inngår i: Surface Engineering, ISSN 0267-0844, E-ISSN 1743-2944, Vol. 28, nr 7, s. 517-525Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Aluminium alloy parts are often formed using cold forming. The transfer of aluminium to the tool is a major problem in these operations. TiB2 has low reactivity with aluminium and has shown promising results in other forming tests. Here, cold forming is simulated in equipment comprising a TiB2 coated tool cylinder and an aluminium cylinder in sliding contact. The coated surfaces are prepared to two surface finishes, and the aluminium cylinders were prelubricated or unlubricated respectively. The test is focused on friction level and number of contacts to reach a threshold friction level. The aluminium surface pretreatment was found to be the most important factor; lubrication lowers the friction significantly. The tool surface finish is also important; polishing lowers and stabilises the friction. The TiB2 coating offered 20‐30% better galling performance than the uncoated steel. However, this improvement was far from that of the best available diamond-like carbon coatings.

    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot materialvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-167056 (URN)10.1179/1743294412Y.0000000017 (DOI)000307963500009 ()
    Tilgjengelig fra: 2012-01-19 Laget: 2012-01-19 Sist oppdatert: 2017-12-08bibliografisk kontrollert
    5. The influence from shape and size of tool surface defects on the occurrence of galling in cold forming of aluminium
    Åpne denne publikasjonen i ny fane eller vindu >>The influence from shape and size of tool surface defects on the occurrence of galling in cold forming of aluminium
    2011 (engelsk)Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 271, nr 9-10, s. 2517-2524Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Aluminium alloys are shaped in cold condition in a large number of industrial applications. Simple geometries can be produced to net shape in a single operation. Galling is an important factor limiting the tool life, the complexity of the shapes and the number of processing steps. A selection of ceramic coatings gives a strongly reduced tendency to galling, even without lubricant, as long as the coating surface is smooth. With rough coating surfaces there is no significant improvement compared to the conventionally used uncoated tool steels. The present investigation concentrates on the character of the surface roughness and its influence on galling. Here, surface defects including pyramidal indents and elongated scratches are introduced in a controlled manner and then characterised with optical microscopy and electron microscopy. After testing, the transfer of work material to the tool is studied using electron microscopy and surface analysis. The influence of the various types of local defects is studied with respect to galling tendencies and friction. The shape and extent of the surface roughness is important for galling resistance. Single indents, symbolizing occasional dents in the coating, initially pick up more aluminium than the surrounding coating but do not influence the galling and friction in total. This implies that the forming tools need fine polishing and gentle handling to avoid dents and initial aluminium pick up. The overall surface roughness level is of higher importance for galling and friction.

    Emneord
    Galling, Surface preparation, Friction, Tool steel, Ceramic coating, Aluminium alloy
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot materialvetenskap; Teknisk fysik med inriktning mot tribomaterial
    Identifikatorer
    urn:nbn:se:uu:diva-162393 (URN)10.1016/j.wear.2011.01.077 (DOI)000294590200167 ()
    Tilgjengelig fra: 2011-11-30 Laget: 2011-11-30 Sist oppdatert: 2017-12-08bibliografisk kontrollert
    6. New understanding of the initiation of material transfer and transfer layer build-up in metal forming: In situ studies in the SEM
    Åpne denne publikasjonen i ny fane eller vindu >>New understanding of the initiation of material transfer and transfer layer build-up in metal forming: In situ studies in the SEM
    2012 (engelsk)Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 292-293, s. 61-73Artikkel i tidsskrift (Fagfellevurdert) Published
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot materialvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-167047 (URN)10.1016/j.wear.2012.05.032 (DOI)000308628400008 ()
    Tilgjengelig fra: 2012-01-19 Laget: 2012-01-19 Sist oppdatert: 2017-12-08bibliografisk kontrollert
    7. Mechanisms of material transfer studied in situ in the SEM: Explanations to the success of DLC coated tools in aluminium forming
    Åpne denne publikasjonen i ny fane eller vindu >>Mechanisms of material transfer studied in situ in the SEM: Explanations to the success of DLC coated tools in aluminium forming
    2012 (engelsk)Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, nr 292, s. 49-60Artikkel i tidsskrift (Fagfellevurdert) Published
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot materialvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-167050 (URN)10.1016/j.wear.2012.05.033 (DOI)000308628400007 ()
    Tilgjengelig fra: 2012-01-19 Laget: 2012-01-19 Sist oppdatert: 2017-12-08bibliografisk kontrollert
    8. Evaluation of an intermittent sliding test for reproducing work material transfer in milling operations
    Åpne denne publikasjonen i ny fane eller vindu >>Evaluation of an intermittent sliding test for reproducing work material transfer in milling operations
    Vise andre…
    2012 (engelsk)Inngår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 52, s. 153-160Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    TiN coated HSS test cylinders from an intermittent sliding test were compared with TiN coated HSS milling inserts from a single insert milling test. A 20NiCrMo2 case hardening steel was used as counter material and work material in the two tests. HSS test cylinders, coated with AlCrN, TiAlN and Al2O3, were also tested in the intermittent sliding test and evaluated with regard to material adhesion. Two distinctly different tribofilms were formed on test cylinders as well as on cutting inserts. One consisting of Mn, Si, Al and O and one consisting of Fe, Mn, Cr, Si and O. The transferred material was similar in appearance and composition, both when comparing the two test methods and when comparing the different tool coatings.

    Emneord
    Transfer, Coating, Chip, Sliding
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot tribomaterial; Teknisk fysik med inriktning mot materialvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-167051 (URN)10.1016/j.triboint.2012.03.015 (DOI)000304798900015 ()
    Tilgjengelig fra: 2012-01-19 Laget: 2012-01-19 Sist oppdatert: 2017-12-08bibliografisk kontrollert
    9. Influence of sliding speed on modes of material transfer as steel slides against PVD tool coatings
    Åpne denne publikasjonen i ny fane eller vindu >>Influence of sliding speed on modes of material transfer as steel slides against PVD tool coatings
    Vise andre…
    2013 (engelsk)Inngår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 58, s. 55-64Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    An intermittent sliding test was used in order to study the formation and build-up of tribofilms during intermittent sliding of PVD coated HSS against case hardening steel (20NiCrMo2). Two cutting tool coatings were tested, TIN and AlCrN, and the influence of sliding speed was evaluated. With moderate speed, two tribofilms were formed separately, one consisting of Mn, Si, Al and O on an intermediate layer of Fe and one consisting of Fe, Mn, Cr and O on an intermediate layer of Cr and Mn. At low sliding speeds an uneven transfer of steel occured while high sliding speeds resulted in thermal softening of the substrate leading to coating failure. AlCrN provided better substrate protection at high speeds than TiN did.

    sted, utgiver, år, opplag, sider
    Elsevier, 2013
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot materialvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-167053 (URN)10.1016/j.triboint.2012.09.012 (DOI)000312610600008 ()
    Tilgjengelig fra: 2012-01-19 Laget: 2012-01-19 Sist oppdatert: 2017-12-08bibliografisk kontrollert
    10. Influence from surface roughness on steel transfer to PVD tool coatings in continuous and intermittent sliding contacts
    Åpne denne publikasjonen i ny fane eller vindu >>Influence from surface roughness on steel transfer to PVD tool coatings in continuous and intermittent sliding contacts
    Vise andre…
    2012 (engelsk)Inngår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 56, s. 9-18Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    A sliding test is used in order to evaluate the influence of tool surface roughness on the material transfer in intermittent and continuous sliding of PVD coated HSS against case hardening steel (20NiCrMo2). Two cutting tool coatings, TiN and AlCrN, and three different surface roughnesses are tested. For polished surfaces the same types of material transfer are obtained irrespective of sliding mode and coating type. If the surfaces are too rough, the tribofilms do not grow thick enough to separate the surfaces and the work material is abrasively worn in both sliding modes. With increased sliding distance, cracking of the TiN coating occurs while the AlCrN coating remains intact.

    Emneord
    Transfer, coating, sliding, roughness
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot materialvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-167054 (URN)10.1016/j.triboint.2012.06.013 (DOI)000308284000002 ()
    Forskningsfinansiär
    VINNOVA
    Tilgjengelig fra: 2012-01-19 Laget: 2012-01-19 Sist oppdatert: 2017-12-08bibliografisk kontrollert
  • 7.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Gerth, Julia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Bexell, Ulf
    Dalarna University.
    Larsson, Mats
    Primateria AB, Uppsala.
    Wiklund, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Influence from surface roughness on steel transfer to PVD tool coatings in continuous and intermittent sliding contacts2012Inngår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 56, s. 9-18Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A sliding test is used in order to evaluate the influence of tool surface roughness on the material transfer in intermittent and continuous sliding of PVD coated HSS against case hardening steel (20NiCrMo2). Two cutting tool coatings, TiN and AlCrN, and three different surface roughnesses are tested. For polished surfaces the same types of material transfer are obtained irrespective of sliding mode and coating type. If the surfaces are too rough, the tribofilms do not grow thick enough to separate the surfaces and the work material is abrasively worn in both sliding modes. With increased sliding distance, cracking of the TiN coating occurs while the AlCrN coating remains intact.

  • 8.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Gerth, Julia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Thersleff, Thomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Bexell, Ulf
    Dalarna University.
    Larsson, Mats
    Wiklund, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Influence of sliding speed on modes of material transfer as steel slides against PVD tool coatings2013Inngår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 58, s. 55-64Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An intermittent sliding test was used in order to study the formation and build-up of tribofilms during intermittent sliding of PVD coated HSS against case hardening steel (20NiCrMo2). Two cutting tool coatings were tested, TIN and AlCrN, and the influence of sliding speed was evaluated. With moderate speed, two tribofilms were formed separately, one consisting of Mn, Si, Al and O on an intermediate layer of Fe and one consisting of Fe, Mn, Cr and O on an intermediate layer of Cr and Mn. At low sliding speeds an uneven transfer of steel occured while high sliding speeds resulted in thermal softening of the substrate leading to coating failure. AlCrN provided better substrate protection at high speeds than TiN did.

  • 9.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Gustavsson, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Dalarna University.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Deformation-activated work material transfer to DLC coatings2014Konferansepaper (Annet vitenskapelig)
  • 10.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Evaluation of TiB2 coatings in cold forming of aluminium2012Inngår i: Surface Engineering, ISSN 0267-0844, E-ISSN 1743-2944, Vol. 28, nr 7, s. 517-525Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aluminium alloy parts are often formed using cold forming. The transfer of aluminium to the tool is a major problem in these operations. TiB2 has low reactivity with aluminium and has shown promising results in other forming tests. Here, cold forming is simulated in equipment comprising a TiB2 coated tool cylinder and an aluminium cylinder in sliding contact. The coated surfaces are prepared to two surface finishes, and the aluminium cylinders were prelubricated or unlubricated respectively. The test is focused on friction level and number of contacts to reach a threshold friction level. The aluminium surface pretreatment was found to be the most important factor; lubrication lowers the friction significantly. The tool surface finish is also important; polishing lowers and stabilises the friction. The TiB2 coating offered 20‐30% better galling performance than the uncoated steel. However, this improvement was far from that of the best available diamond-like carbon coatings.

  • 11.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Evaluation of TiB2 coatings in cold forming of aluminium2011Konferansepaper (Annet vitenskapelig)
  • 12.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Influence from PVD coatings on galling tendency in cold forming2010Konferansepaper (Annet vitenskapelig)
  • 13.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Influence of aluminium pre-treatment on galling in cold forming2009Konferansepaper (Annet vitenskapelig)
  • 14.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Lab test simulation of galling in cold forming of aluminium2008Inngår i: NordTrib 2008, 2008Konferansepaper (Fagfellevurdert)
  • 15.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Laboratory test simulation of aluminium cold forming – influence from PVD tool coatings on the tendency to galling2010Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 204, nr 21-22, s. 3606-3613Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cold forming of aluminium is a group of very efficient methods used in a number of industrial applications. Two of the major factors limiting the tool life and restricting the complexity of the shapes produced, are galling, i.e. transfer of aluminium to the tool surface, which leads to problems in successive forming, and high stresses occurring when forming complex shapes. Both phenomena are closely related to friction and adhesion in the tool to workpiece interface. Earlier investigations have shown that aluminium is transferred to the tool steel surface regardless of the surface roughness of the tool. This has been proposed to be due to the hard native oxide on the soft aluminium leading to a mechanical gripping in the tool surface.The present paper investigates the influence of ceramic coatings on the tendency to galling. This is done by plastic forming of aluminium against coated tool steel rods in a lab test. The test scans over a wide load interval while monitoring the coefficient of friction. The transfer of work material to the tool is studied in the SEM. The test is focused on the friction level and on the number of contacts before a critical friction level is reached.The test set-up comprises two crossed cylinders in sliding contact, one made of coated tool material and the other of work material. Eight commercial coatings were included; DLC, TiAlN, TiN and TiCN as single layer or as multilayer combinations, with hardness values ranging from 800 HV to 3500. HV. All substrates were the same tool steel material (H13), prepared to two different surface finishes. The aluminium work piece cylinders of AA6082 were prepared by two different pre-treatments, soft-annealing followed by industrially used solid lubrication and pickling, respectively.The coating material, preparation of the tool surface finish and the aluminium surface pre-treatment all proved important with respect to galling tendencies and friction levels. Three of the DLC coatings showed very promising behaviour, also without lubricant, but surface roughness deteriorates the galling resistance. The other low-friction coatings tested neither improved the galling resistance nor reduced the friction significantly, compared to the uncoated tool steel.

  • 16.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Laboratory test simulation of aluminium cold forming: influence from PVD coatings on the tool on the tendency to galling2009Konferansepaper (Annet vitenskapelig)
  • 17.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Laboratory test simulation of galling in cold forming of aluminium2009Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 267, nr 12, s. 2278-2286Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cold forming of aluminium is a group of very efficient methods, which are successfully used in a number of industrial applications. Two of the major factors limiting the tool life and restricting the shapes and sizes possible to produce, are galling, i.e. transfer of work material to the tool surface, and high stresses occurring when forming complex shapes. Both phenomena are closely related to the friction and adhesion in the tool to workpiece interface.

    The present paper investigates the influence of several surface parameters to the tendency to galling. This is done by forming aluminium using tool steel in a geometrically simplified lab test. The test scans over a wide load interval while monitoring the coefficient of friction. The corresponding transfer of work material to the tool surface is studied in the SEM after testing. The test is focused on the initial tool contact and also on the number of contacts before a critical friction level is reached.

    The test set-up comprises two crossed cylinders in sliding contact, one made of tool steel and one of work material. Three commercial tool materials were included, each prepared to two surface finishes. The aluminium workpiece cylinders of AA6082 were prepared by two different pre-treatments, solid lubrication followed by soft annealing and pickling, respectively.

    The respective importance of the tool material, preparation of the tool surface finish and the aluminium surface pre-treatment are compared with respect to initial galling tendencies and friction stability. The practical implications for real forming applications are discussed.

  • 18.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Mechanisms of transfer of aluminium to PVD-coated forming tools2012Inngår i: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 46, nr 3, s. 299-312Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cold forging is a group of methods effectively used in a number of industrial applications to form aluminium. Tool life and complexity of the possible shapes are mainly restricted by galling; the uneven tool surfaces caused by lumps of transferred material lead to surface damage on successive parts formed and/or problems in successive forming operations, and high stresses occurring when forming complex shapes. Earlier investigations have shown that improved surface roughness of an uncoated steel tool decreases the amount of adhered aluminium on the tool, but does not decrease the friction in the long run. Testing has also shown that when using conventional forming tools it is very important to have sufficient lubrication to avoid galling. Addition of an optimized low-friction PVD-coating decreases the galling tendency and increases the tolerance to insufficient lubrication and lubricant film breakthrough, as long as the coating surface is smooth, whilst other similar coatings have little or no effect. The present article further investigates the mechanism behind the transfer of aluminium to the coatings. All coatings were found to be intact after testing, and so the differences were concluded to lie in the chemical properties of the coating and, if these are favourable, then in surface roughness on the micro scale.

  • 19.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    The Importance of Tool Surface Roughness on the Galling Tendencies in Cold Forming of Aluminium2010Konferansepaper (Fagfellevurdert)
  • 20.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    The influence from shape and size of tool surface defects on the occurrence of galling in cold forming of aluminium2011Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 271, nr 9-10, s. 2517-2524Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aluminium alloys are shaped in cold condition in a large number of industrial applications. Simple geometries can be produced to net shape in a single operation. Galling is an important factor limiting the tool life, the complexity of the shapes and the number of processing steps. A selection of ceramic coatings gives a strongly reduced tendency to galling, even without lubricant, as long as the coating surface is smooth. With rough coating surfaces there is no significant improvement compared to the conventionally used uncoated tool steels. The present investigation concentrates on the character of the surface roughness and its influence on galling. Here, surface defects including pyramidal indents and elongated scratches are introduced in a controlled manner and then characterised with optical microscopy and electron microscopy. After testing, the transfer of work material to the tool is studied using electron microscopy and surface analysis. The influence of the various types of local defects is studied with respect to galling tendencies and friction. The shape and extent of the surface roughness is important for galling resistance. Single indents, symbolizing occasional dents in the coating, initially pick up more aluminium than the surrounding coating but do not influence the galling and friction in total. This implies that the forming tools need fine polishing and gentle handling to avoid dents and initial aluminium pick up. The overall surface roughness level is of higher importance for galling and friction.

  • 21.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jarmar, Tobias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Rooth, Mårten
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    In vitro bioactivity of Atomic Layer Deposited titanium dioxide on titanium and silicon substrates2008Inngår i: BIOCERAMICS, VOL 20, PTS 1 AND 2 / [ed] Daculsi G, Layrolle P, 2008, Vol. 361-363, s. 689-692Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A non-bioactive implant device can easily be changed to in vitro bioactive with a thin This crystalline coating can be deposited very thin with great step coating of crystalline TiO2 coverage at a low temperature with Atomic Layer Deposition (ALD). An anatase TiO2 coating was built up atomic layer by atomic layer using TiI4 and H2O as precursors in a hot wall furnace. Several hundreds of cycles resulted in a 10-30nm well defined TiO2 of anatase phase on both Si and Ti substrates. These coatings were shown to be bioactive when immersed in simulated body fluid in vitro, as hydroxyapatite (HA) formed on the surface. The surface roughness of the substrates affected the adhesion of the HA. The adhesion was low on the smooth Si but much better on the 100 times rougher Ti. The ALD technique is promising for coating substrates of all shapes with bioactive crystalline TiO2 at a low temperature.

  • 22.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jarmar, Tobias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Wiklund, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Physical vapour deposition and bioactivity of crystalline titanium dioxide thin films2008Inngår i: Trends in Biomaterials & Artificial Organs, ISSN 0971-1198, Vol. 22, nr 2, s. 104-110Artikkel i tidsskrift (Fagfellevurdert)
  • 23.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jenei, Istvan Zoltan
    Stockholm University.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Morphology and composition of tribofilms deposited using a tribochemical burnishing technique2013Konferansepaper (Fagfellevurdert)
  • 24.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jenei, Istvan Zoltan
    Stockholms universitet.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Morphology and composition of tribofilms deposited using a tribochemical burnishing technique2014Inngår i: Tribology - Materials, Surfaces & Interfaces, ISSN 1751-5831, E-ISSN 1751-584X, Vol. 8, nr 1, s. 14-20Artikkel i tidsskrift (Fagfellevurdert)
  • 25.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Kawakami, Ayumi
    YKK Corporation, Japan.
    Mikado, Hiroko
    YKK Corporation, Japan.
    Wiklund, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Kawamura, Shingo
    YKK Corporation, Japan.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Wear mechanisms of WC-Co cemented carbide tools and PVD coated tools used for shearing Cu-alloy wire2018Konferansepaper (Annet vitenskapelig)
  • 26.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Mikado, H.
    YKK Corp, Machinery & Engn Grp, Tokyo, Japan.
    Kawakami, A.
    YKK Corp, Machinery & Engn Grp, Tokyo, Japan.
    Wiklund, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Kawamura, S.
    YKK Corp, Machinery & Engn Grp, Tokyo, Japan.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Wear mechanisms of WC-Co cemented carbide tools and PVD coated tools used for shearing Cu-alloy wire in zipper production2019Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 420, s. 96-107Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To form the individual elements, that together form a zipper, a pre-formed Cu-alloy wire is sheared using cemented carbide tools. The wear caused by the relatively soft copper alloy on the much harder tool is generally quite slow. However, millions of elements are to be sheared so eventually the wear becomes unacceptable and the tool needs to be exchanged. To improve product quality, as well as minimize down time and material consumption, the tool life needs to be prolonged. To achieve this the wear process needs to be better understood. Uncoated tools used for an increasing number of shearing events have been studied in detail using high resolution SEM and EDS, to map the propagating wear and get an insight into the wear mechanisms. Transfer of material from the Cu-alloy to the tool occurs and the wear is highly concentrated to specific areas. This wear occurs on a very fine scale, limited to within individual WC grains at each event. Tools coated with PVD CrC and PVD CrN have been studied for comparison with the uncoated cemented carbide. Both coatings successfully protect the cemented carbide tool from wear, however occasional flaking occurs and then the cemented carbide becomes exposed and subsequently worn. The differences in performance and wear mechanisms between the uncoated and coated tools are discussed, with focus on the capability of the coatings to prolong the tool life.

  • 27.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Norgren, Susanne
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Dalarna University.
    Cemented carbide wear initiation in sliding contact with iron ore2019Inngår i: Proceedings of 2nd Sweden-China Symposium on Tribology, 2019Konferansepaper (Annet vitenskapelig)
  • 28.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Norgren, Susanne
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Dalarna University.
    Influence of cemented carbide binder type on wear initiation in rock drilling – investigated in sliding wear against magnetite rock2019Inngår i: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917, Vol. 85, artikkel-id 105035Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cemented carbides, containing hard WC grains in a ductile Co binder, are commonly used as the rock crushing part of rock drills. They generally work well and show moderate and gradual wear in rock drilling applications. However, due to health issues, an alternative to Co is sought for, which will not compromise the performance. In the present work, the initiation of wear of cemented carbides with the two alternative binders Ni and Fe are investigated and compared to the common Co containing material in a sliding test. The sliding counterpart is magnetite, representing a rock type generally causing slow wear of the cemented carbides.

    The results show that magnetite is immediately transferred to the cemented carbide thus forming thin layers, mainly on top of the binder, and WC grain fragments are removed. The chain of events is similar irrespective of binder, however the severity shows a strong dependence. The cemented carbide grade with the Ni binder shows relatively rapid wear initiation, compared to that with the Fe binder that shows moderate initiation and that with Co that is barely worn at all.

  • 29.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Norgren, Susanne
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap. Sandvik Min & Rock Technol, Stockholm, Sweden.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Yvell, Karin
    Dalarna Univ, Mat Sci, Falun, Sweden.
    Olsson, Mikael
    Dalarna Univ, Mat Sci, Falun, Sweden.
    Influence of cemented carbide binder type on wear initiation in rock drilling – investigated in sliding wear against magnetite rock2019Inngår i: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917, Vol. 85, artikkel-id 105035Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cemented carbides, containing hard WC grains in a ductile Co binder, are commonly used as the rock crushing part of rock drills. They generally work well and show moderate and gradual wear in rock drilling applications. However, due to health issues, an alternative to Co is sought for, which will not compromise the performance. In the present work, the initiation of wear of cemented carbides with the two alternative binders Ni and Fe are investigated and compared to the common Co containing material in a sliding test. The sliding counterpart is magnetite, representing a rock type generally causing slow wear of the cemented carbides.The results show that magnetite is immediately transferred to the cemented carbide thus forming thin layers, mainly on top of the binder, and WC grain fragments are removed. The chain of events is similar irrespective of binder, however the severity shows a strong dependence. The cemented carbide grade with the Ni binder shows relatively rapid wear initiation, compared to that with the Fe binder that shows moderate initiation and that with Co that is barely worn at all.

  • 30.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, M.
    Högskolan Dalarna.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Influence of tool steel microstructure on initial material transfer in metal forming-In situ studies in the SEM2013Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 302, nr 1-2 SI, s. 1249-1256Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Metal forming constitutes a group of industrially important processes to form metallic components to net shape. When forming aluminium and other materials that tend to stick to the tools, problems associated with material transfer, e.g. galling, may occur. In a previous study by the present authors, in situ observations of aluminium transfer during sliding contact in the SEM revealed that the surface topography and chemical composition of the tool steel counter surface have a strong impact on the initial material transfer tendency. Even if carefully polished to a very smooth surface (Ra < 50 nm), transfer of aluminium was found to immediately take place on a very fine scale and preferentially to the surface irregularities presented by the slightly protruding M(C,N) particles (height 15 nm) in the tool steel. In contrast, the less protruding M6C carbides, as well as the martensitic steel matrix exhibited very little initial transfer. The mechanism behind the preferential pick-up tendency displayed by the M(C,N) particles was not fully understood and it was not possible to determine if the decisive mechanism operates on the microstructural scale, the nanoroughness scale or the chemical bonding scale. In the present study, these mechanisms have been further investigated and analysed by comparing the very initial stages of material transfer onto different types of tool steels in sliding contact with aluminium in the SEM. The tool steels investigated cover conventional ingot cast and powder metallurgy steel grades, selected to possess a range of different types, amounts and sizes of hard phase particles, including MC, M(C,N), M7C3 and M6C. The transfer mechanisms are investigated using high resolution SEM, and the differences between the different microstructures and carbide types are carefully analysed. The implications for real metal forming are discussed. 

  • 31.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap. Materials Science, Dalarna University, Sweden.
    Almqvist, Bjarne
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Geofysik.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Initial surface failure and wear of cemented carbides in sliding contact with different rock types2018Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 408-409, s. 43-55Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The initial wear, deformation and degradation of cemented carbide in contact with different rock types are studied using a crossed cylinder sliding test. The sliding distance is limited to centimetres at a time, interrupted by successive SEM analysis. This allows for careful studies of the gradually changing microstructure of the cemented carbide during the test. Five different rock types are included; granite, metal sulphide ore, mica schist, quartzite and marble. All rock types are very different in microstructure, composition and properties. The cemented carbide grade used for the evaluation contains 6 wt% Co and fine (~ 1 µm) WC grains, a grade commonly used in rock drilling. The results show that the cemented carbide microstructure becomes altered already during the very first contact with rock. The initial wear rate and wear character is highly influenced by the rock type. The initial wear of the cemented carbide is highest against quartzite and lowest against marble.

  • 32.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Dalarna University.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Initial deformation and wear of cemented carbides for rock drilling as evaluated by a sliding wear test2015Konferansepaper (Fagfellevurdert)
  • 33.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Initial deformation and wear of cemented carbides in rock drilling as examined by a sliding wear test2017Inngår i: INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS, ISSN 0263-4368, Vol. 64, s. 7-13Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Due to a combination of high hardness and toughness, resulting in excellent wear resistance, cemented carbides are commonly used as the rock crushing component in rock drilling. The present paper presents a unique study where the very initial stages of deformation and wear of cemented carbide in sliding contact with rock are followed in small incremental steps. After each step, a pre-determined area within the wear mark is characterized using high resolution SEM and EDS. This facilitates analysis of the gradual deformation, material transfer, degradation and wear. The deterioration mechanisms found in this sliding test are similar to those observed in actual rock drilling. Cemented carbide grades with different microstructures show significant differences, where a higher amount of Co and a larger WC grain size both are associated to more wear.

  • 34.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Dalarna University.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Initiation of galling in forming of ductile metals: – differences between aluminium and austenitic stainless steel studied in situ in the SEM2012Inngår i: Nordtrib, Trondheim, Norway, 2012, 2012Konferansepaper (Fagfellevurdert)
  • 35.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Initiation of Galling in Metal Forming: Differences Between Aluminium and Austenitic Stainless Steel Studied In Situ in the SEM2013Inngår i: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 50, nr 3, s. 431-438Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High friction and transfer of work material to tool surfaces constitute important industrial problems in forming of many metals and alloys. However, it is very hard to gain a deeper understanding of these phenomena by studying real forming operations. In this paper, we have tried to gain fundamental understanding by avoiding as much as possible of the complexity of real forming. This has been realised by studying the friction and material transfer between well-defined tool material surfaces; uncoated and DLC-coated tool steel, and a needle shaped austenitic stainless steel tip, in situ in the SEM. The tool materials were tested in two conditions; well polished and well polished with local intentional scratches. It was found that work material was immediately transferred to the tool steel surface. When passing an intentional scratch, the local transfer was on a much larger scale, and the friction was higher, but the effect was mostly local. For the polished DLC-coated surface, almost no work material was transferred and the friction was low. An intentional scratch in the polished DLC surface barely influenced the galling behaviour. The present results are discussed in the light of previously published results from an analogous study with aluminium as work material.

  • 36.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Dalarna University.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Mechanisms of material transfer studied in situ in the SEM: Explanations to the success of DLC coated tools in aluminium forming2012Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, nr 292, s. 49-60Artikkel i tidsskrift (Fagfellevurdert)
  • 37.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Dalarna University.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    New understanding of the initiation of material transfer and transfer layer build-up in metal forming: In situ studies in the SEM2012Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 292-293, s. 61-73Artikkel i tidsskrift (Fagfellevurdert)
  • 38.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Dalarna University.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Transfer of titanium in sliding contacts - New discoveries and insights revealed by in situ studies in the SEM2013Konferansepaper (Fagfellevurdert)
  • 39.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Jenei, Istvan Zoltan
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Transfer of titanium in sliding contacts: New discoveries and insights revealed by in situ studies in the SEM2014Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 315, nr 1-2, s. 87-94Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Titanium and its alloys generally display poor tribological properties in sliding contacts due to their high chemical activity and strong adhesion to the counter surface. The strong adhesion causes a high tendency to transfer and ultimately galling or build-up edge formation, resulting in severe surface damage. As a result, forming and machining of titanium and its alloys are generally associated with significant problems such as high friction, rapid tool wear and poor surface finish of the formed/machined surface. In the present study, in situ tests in a scanning electron microscope have been performed to increase the understanding of the mechanisms controlling the initial transfer of titanium (Grade 2) in sliding contact with tool surfaces. Tool materials included cover cold work tool steel, cemented carbide, CVD deposited Al2O3 and PVD deposited DLC. In these tests, a relatively sharp tip, representing the titanium work material, slides against a flat surface, representing the tool. The contact conditions result in plastic deformation of the work material against the tool surface, thereby simulating forming or machining. The limited and well-defined contact, along with the possibility to study the sliding in the SEM, makes it possible to correlate local surface variations to transfer of work material and frictional response. Post-test characterization of the contact surfaces was performed by high-resolution SEM, TEM, EDS and EELS. The initial friction was low and stable against all tested materials, but then gradually escalated against all surfaces except the DLC. The friction escalation was associated to increasing levels of transfer, while the DLC stayed virtually free from transfer. From these very initial sliding tests DLC is a promising tool coating in forming and machining of titanium. 

  • 40.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Dalarna University.
    Staffan, Jacobson
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Influence of tool steel microstructure on initial material transfer in metal forming – In situ studies in the SEM2013Konferansepaper (Annet vitenskapelig)
  • 41.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Dalarna University.
    Staffan, Jacobson
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Surface degradation of cemented carbides in scratching contact with granite and diamond: the roles of microstructure and composition2015Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 342, s. 210-221Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cemented carbides are composite materials comprising metal carbide grains in a more ductile metallic binder. This microstructure results in a combination of high hardhess and toughness, making them commonly used as rock crushing parts in rock drilling, where they usually show wear on a very fine scale. The hardness and toughness can ultimately be tuned for the application by adjusting the carbide grain size, binder fraction and composition. In the present investigation, the initial micro-scale deformation and wear of polished cemented carbide surfaces is studied by micro scratching with diamond and granite styli, and also by instrumented micro and nanoindentation. The deformation and wear is evaluated on the sub-micrometer scale using high resolution FEG-SEM and FIB cross sectioning. The selected microstructures include besides four cemented carbide grades that are commonly used in rock drilling also binderless and Ni containing grades. This wider range of cemented carbides is used to gain fundamental insights into the relations between microstructure and micro-scale deformation and wear. The results are discussed with respect to their significance for wear of cemented carbides in rock drilling operations.

  • 42.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap. Dalarna Univ, Mat Sci, Falun, Sweden.
    Yvell, Karin
    Dalarna Univ, Mat Sci, Falun, Sweden.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    On the deformation mechanisms of cemented carbide in rock drilling: Fundamental studies involving sliding contact against a rock crystal tip2018Inngår i: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917, Vol. 77, s. 141-151Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cemented carbide is a composite material, most commonly consisting of tungsten carbide grains in a metallic matrix of cobalt. The combination of a hard ceramic phase in a ductile metallic matrix combines high hardness and ability to withstand plastic deformation with toughness to avoid cracking and fracturing. Since these properties are very important in rock drilling, cemented carbides are frequently used in such applications. In earlier work, it was found that granite in sliding contact with considerably harder cemented carbides not only results in plastic deformation of the cemented carbide composite, but also in plastic deformation of some of the individual WC grains. The latter observation is remarkable, since even the two hardest granite constituents (quartz and feldspar) are significantly softer than the WC grains. This tendency to plastic deformation of the WC grains was found to increase with increasing WC grain size. The present investigation aims to increase the understanding of plastic deformation of cemented carbides in general, and the individual WC grains in particular, in a situation representative for the rock drilling application. The emphasis is put on explaining the seemingly paradoxical fact that a nominally softer counter material is able to plastically deform a harder constituent in a composite material. The experimental work is based on a scratch test set-up, where a rock crystal tip slides against a fine polished cemented carbide surface under well-controlled contact conditions. The deformation and wear mechanisms of the cemented carbide are evaluated on the sub micrometer scale; using high resolution FEG-SEM, EDS, EBSD, BIB and FIB cross-sectioning. The size of the Co-pockets, together with the shape and size of WC grains, turned out to be decisive factors in determining the degree of carbide deformation. The results are discussed with respect to their industrial importance, including rock drilling.

  • 43.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Dalarna University.
    Yvell, Karin
    Dalarna University.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Soft rock scratches hard cemented carbide2015Konferansepaper (Fagfellevurdert)
  • 44.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Staffan, Jacobson
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    The influence from shape and size of tool surface defects on the occurrence of galling in cold forming of aluminium2011Konferansepaper (Annet vitenskapelig)
  • 45.
    Heinrichs, Jannica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Yvell, Karin
    Dalarna University.
    Olsson, Mikael
    Dalarna University.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Influence of hardness and microstructure on the mechanisms of deformation and wear of cemented carbides for rock drilling2014Konferansepaper (Annet vitenskapelig)
  • 46.
    Hiroko, Mikado
    et al.
    YKK.
    Heinrichs, Jannica
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Wiklund, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Kawamura, Shingo
    YKK.
    Jacobson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Initiation wear of cemented carbide tools used in copper processing - evaluated in sliding contact2019Inngår i: Proceedings of International Conference on the Science of Hard Materials, Khao Lak, Thailand, 2019Konferansepaper (Annet vitenskapelig)
  • 47.
    Jacobson, Staffan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Heinrichs, Jannica
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Mikael
    Dalarna University.
    New experimental findings on the role of initial material transfer in determining friction and surface damage2013Konferansepaper (Fagfellevurdert)
  • 48.
    Lindberg, Fredrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Heinrichs, Jannica
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Ericson, Fredric
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrostrukturlaboratoriet, MSL.
    Thomsen, Peter
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Hydroxylapatite growth on single-crystal rutile substrates2008Inngår i: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 29, nr 23, s. 3317-3323Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Titanium is widely used as an implant material. In addition to the bulk properties of titanium, the biological response is to a large degree controlled via the surface. The native amorphous titanium oxide that forms spontaneously on the surface gives a very good biological response. Lately it has been shown that crystalline titanium oxides (rutile and anatase) have in vitro bioactive properties. In addition to its potential for new materials development, this finding also opens up for the possibility of studying the mechanisms of bioactivity on materials with strictly controlled surfaces. In this paper the mechanisms behind the in vitro bioactivity are studied, using rutile single crystals. Three single-crystal rutile substrates: (100), (110), and (001), and a polycrystalline rutile substrate obtained by physical vapour deposition were soaked in a phosphate buffered saline solution for up to 4 weeks. The hydroxylapatite films that formed were analysed by X-ray diffraction, scanning electron microscopy, focused ion beam, and transmission electron microscopy. The hydroxylapatite grew faster on the (001) surface than on the other two. It was also found that on the (001) surface the direction of fast growth in hydroxylapatite was aligned parallel to the surface. This is in contrast to the (110) rutile surface where the fast growth of the hydroxylapatite crystal was directed outwards from the surface. The (100) face had poor adhesion at the interface. The orientations of the precipitated crystallites play a significant role in the faster coverage of the (001) rutile face. Based on the experimental results, a model for the hydroxylapatite growth process is given.

  • 49.
    Olander, Petra
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Heinrichs, Jannica
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Initiation and propagation of tool wear in turning of titanium alloys - Evaluated in successive sliding wear test2019Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 426-427, nr Part B, s. 1658-1666Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Titanium alloys are known to cause significant crater wear on the rake face of cutting inserts when exposed to the fresh chip during cuffing, limiting the lifetime of the tool. Previous studies have shown that wear surfaces on inserts has a crater filled with transferred titanium. The WC grains in the bottom of the crater are depleted of carbon, resulting in a top surface rich in tungsten. To further investigate the initiation of wear in the present study a sliding test, previously developed to imitate the conditions on the rake face during cuffing, was used. The test was performed in interrupted mode, allowing intermediate SEM studies of the tool surface, while successively increasing the sliding distance. A cemented carbide grade, H13A, commonly used for cutting titanium alloys, and titanium alloy Ti6Al4V were used as model materials. The results from the sliding tests showed that both transfer of titanium and wear of the cemented carbide composite occur simultaneously. The wear is shallow and occurs on a very small scale, which adds up to a large crater, which is continuously filled with a smooth layer of titanium.

  • 50.
    Olander, Petra
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Heinrichs, Jannica
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Initiation and propagation of tool wear in turning of titanium alloys – evaluated in successive sliding wear test2019Inngår i: Proceedings of Wear of Materials Conference, Miami, Florida, USA, 2019Konferansepaper (Annet vitenskapelig)
12 1 - 50 of 58
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