Oxidation wear
Oxidation wear describes the corrosion of metals caused by direct reaction with oxygen . Usually this refers to the signs of wear of cutting tools ( wear (cutting) ), the surface of which is oxidized by atmospheric oxygen.
Significant oxidation of high-quality metals only occurs at high temperatures from approx. 700 ° C. Most cutting tools are made of hard metal and contain tungsten carbide in a cobalt matrix . Both components are sensitive to oxidation. The resulting porous oxide layer can easily be removed by the chip. At very high temperatures, the oxides are volatile and evaporate. When cutting non-metallic materials (wood, plastics), ingredients or decomposition products of the material can also accelerate corrosion.
Oxide-ceramic cutting materials are hardly susceptible, as oxides such as aluminum oxide cannot be further oxidized, but such cutting edges can contain titanium boride or titanium nitride , for example , which oxidize at high temperatures. There are also hard carbides that are less sensitive to oxidation than tungsten carbide, for example silicon carbide .
The oxide layer is preferably formed at points on the cutting edge where high temperatures occur and where atmospheric oxygen has free access; this shows up as notch wear.
Individual evidence
- ↑ Herbert Schönherr: Machining production. Oldenbourg Verlag, Munich 2002, ISBN 3-486-25045-0 , p. 46.
- ↑ Werner Degner, Hans Lutze, Erhard Smejkal: Spanende Formung. Theory - calculation - reference values. 17th edition. Hanser Verlag, Munich 2015, ISBN 978-3-446-44544-4 , pp. 81-83.
- ↑ Hans Kurt Toenshoff: Spanen: Basics. 2nd Edition. Springer Verlag, Berlin / Heidelberg 2004, ISBN 3-662-09964-0 , pp. 155–158.
- ↑ Tiziano Panico: Assessment of the edge loading when shearing high-strength steel sheets using the finite element method. Dissertation. Technical University of Munich, Munich 2012, pp. 20–24. (on-line)
See also
Web links
- Prevention of cutting value recommendations (accessed on August 3, 2018)