Sliding wear behaviour of a liquid nitrocarburised precipitation-hardening (PH) stainless steel

A precipitation-hardening stainless steel, of commercial trade name CORRAX, similar to DIN X3CrNiMoAl 13-8-2 grade steel (W.Nr. 1.4534) has been subjected to liquid nitrocarburising in cyanide salt bath to enhance its wear behavior. The wear resistance was evaluated using a pin-on-disk wear testing method with a tungsten carbide counterface against three different steel conditions: nitrocarburised, age-hardened (aged) and solution treated (delivery state). The variation of friction coefficient and wear volume is presented as a function of applied normal load (5, 6, 8 and 10 N) and sliding distance for a constant running speed (0.6 m/s). The pin end (in contact with the disk) had a radius of curvature up to 0.40 mm. The maximum wear resistance of the nitrocarburised specimens is found up to 16 times higher than that of the age-hardened and 31 times higher than that of the solution treated ones. Microscopical observations revealed that the principal wear mechanisms of the nitrocarburized steel are micropolishing and microcutting. (C) 2004 Elsevier B.V. All rights reserved.