Improvement of wear resistance of a lean duplex stainless steel through low temperature plasma nitriding

DIB, JOSEFINA ANDREA; STRUBBIA, RENATA; GOMEZ, BERNARDO; HEREÑU, SILVINA

Vitoria

Conferencia; Fourth International Brazilian Conference on Tribology - Tribo Br 2023; 2023

Lean duplex stainless steels (LDSS) have great mechanical and corrosion resistance with a low cost. However, for some applications their wear resistance needs to be improved. A LDSS (LDX2101) was plasma nitrided (PN) at 250 °C for 6 hours in a 25%N2 - 75%H2 atmosphere. X-Ray diffraction, roughness parameters and microhardness are measured. Dry sliding tests are carried out in a ball-on-disk tribometer, using aluminium oxide balls as counterpart. Different sliding distances are investigated. The friction coefficient is continuously measured. Wear rates are calculated, and wear tracks are studied. After PN, expanded austenite and ferrite are formed and precipitation of detrimental CrN is not detected. In as-received (AR) tests the wear mainly takes place during the initial sliding stage and all the PN tests result in lower wear rates than AR ones. The results are explained considering the supersaturated solid solution of nitrogen expanded phases that increase the hardness of the surface.