On wear resistance of tool steel
2012 (English)In: Journal of Manufacturing Processes, ISSN 1526-6125, Vol. 14, no 3, 195-198 p.Article in journal (Refereed) Published
Maintaining a reasonably low cutting tool wear when producing forming tools is a general challenge in the development of new forming tool materials. The tool life of a hot forming tool steel (H13) has been significantly improved by reducing its Si-content from 1.0 to 0.06 wt.%. However, this modified H13 (MH13) also displays a reduced cutting tool life due to higher cutting forces and a stronger tendency to form built up layers (BUE) on the cutting edge. This paper explains why.
Gleeble tests of MH13 revealed a significantly higher flow stress in the 820–900 °C temperature interval in MH13 compared to H13. Thermo-Calc simulations showed that when reducing the Si-content from 1.0 to 0.06 wt.% the initial temperature for ferrite-to-austenite transformation (A1) was reduced from 900 °C to 820 °C. Knowing that austenite has totally different mechanical and thermal properties than ferrite, the difference in A1 between the two steels explains the higher cutting forces and higher tendency for BUE-formation. The conclusion is that the difference in machinability between H13 and MH13 is primarily related to their difference in A1.
An attempt was also made to find a new tool material composition that can combine the wear resistance of MH13 and the good machinability of H13. Thermo-Calc simulations were performed with slightly modified alloying content without changing its properties as a good forming tool material, with the aim to increase A1. For instance, reducing the Mn content from 0.5 to 0.05 wt.% proved to increase A1 from 820 to 850 °C.
Place, publisher, year, edition, pages
2012. Vol. 14, no 3, 195-198 p.
Research subject Engineering Science with specialization in Materials Science
IdentifiersURN: urn:nbn:se:uu:diva-172426DOI: 10.1016/j.jmapro.2012.03.002OAI: oai:DiVA.org:uu-172426DiVA: diva2:514624