Title: Damage mechanisms in materials for cold forging dies under loading conditions typical for dies

Authors: Gerhard Jesner, Stefan Marsoner, Ingrid Schemmel, Karl Haeussler, Reinhold Ebner, Reinhard Pippan

Addresses: Materials Center Leoben Forschung GmbH, Roseggerstrasse 12, 8700 Leoben, Austria; Boehler Edelstahl GmbH & Co KG, Mariazeller Strasse 25, 8605 Kapfenberg, Austria. ' Materials Center Leoben Forschung GmbH, Roseggerstrasse 12, 8700 Leoben, Austria. ' Boehler Edelstahl GmbH & Co KG, Mariazeller Strasse 25, 8605 Kapfenberg, Austria. ' Thyssen Krupp Presta AG, Essanestrasse 10, 9492 Eschen, Liechtenstein. ' Materials Center Leoben Forschung GmbH, Roseggerstrasse 12, 8700 Leoben, Austria. ' Erich Schmid Insitute for Materials Science of the Austrian Academy of Sciences, Jahnstrasse 12, 8700 Leoben, Austria.

Abstract: PM-tool steels are the most widely used materials for cold forging dies. The lifetime of such dies is mainly controlled by fatigue damage, which consists of the fatigue crack initiation and fatigue crack growth. A special technique was developed in order to characterise the fatigue crack initiation under stress ratios which are typical in cold forging dies. The fatigue cracks are simultaneously generated by the cracking of carbides, debonding of carbide/metallic matrix interfaces or by crack initiation in the matrix. Fatigue crack growth of these high-strength tool steels is plasticity-controlled and comparable to that of ductile materials.

Keywords: PM tool steel; damage mechanisms; cold forging dies; fatigue crack nucleation; crack growth; crack initiation.

DOI: 10.1504/IJMMP.2008.018736

International Journal of Microstructure and Materials Properties, 2008 Vol.3 No.2/3, pp.297 - 310

Published online: 16 Jun 2008 *

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