Ranking the performance of lubricants, tool steels and PVD coatings for the forming of high strength steel using pin-on-disc testing
2009 (English)In: Tool09: Tool steels, june 2nd-4th 2009 in aachen, germany, 2009Conference paper (Other academic)
The increasing use of high strength steels in a variety of mechanical engineering applications has illuminated problems associated with galling in sheet metal forming operations. Galling is a tribological phenomenon associated with transfer of material from the steel sheet to the tool surface during forming resulting in seizure of the tool/steel sheet contact and extensive scratching of the steel sheet surface. As a result, a number of concepts have been developed in order to reduce the tendency to galling in sheet metal forming, including the development of new dry lubricants, new forming tool steel grades and improved surface engineering treatments such as the deposition of low friction CVD- and PVD-coatings. In the present study the potential performance of these concepts in the forming of hot and cold rolled high strength steel as well as electro and hot-dip galvanized high strength steel has been evaluated using pin-on disc testing. In the tests, two different lubricants, a dry lubricant and a pre-lube oil, two different cold work tool steels, a conventional steel grade and a nitrogen alloyed PM steel grade, and two different PVD coatings, (Ti,Al)n and CrC/C, were evaluated. Post-test examination of the tribosurfaces using FEG-SEM, EDX and 3D surface profilometry was performed in order to evaluate the mechanisms controlling the material transfer and wear. In summary, the results show that the laboratory testing combined with post-test microscopy and surface analysis give valuable information in order to rank the galling resistance of lubricants, tool steels and PVD-coatings.
Place, publisher, year, edition, pages
sheet metal forming, high strength steels, galling, dry lubricant, tool steels, PVD-coatings
Metallurgy and Metallic Materials
Research subject Engineering Science with specialization in Tribo Materials
IdentifiersURN: urn:nbn:se:uu:diva-159384OAI: oai:DiVA.org:uu-159384DiVA: diva2:444676