Wear behavior analysis on treated AISI 421 stainless steel under dry sliding conditions

Abstract

Stainless steel is affordable material and available commercially in the market. AISI 421 Martensitic stainless steel offers good hindrance to wear and corrosion. The hardness, strength, and wear resistance of AISI 421 martensitic stainless steel were satisfactory, but it lacks ductility. Thereby, these materials are applicable for manufacturing of cutting tools and in usage where high wear resistances are required. In order to make use of martensitic material for commercial purpose, heat treatment methods like annealing, tempering, normalizing are available and among which vacuum tempering processes were chosen for this research work. Annealing and normalizing are good at softening the martensitic stainless steel material. The objective is to keep the hardness stable and promote ductility in martensitic stainless steel material. Three samples of AISI 421 martensitic stainless steel samples with diameter of 10 mm and with length of 40 mm were taken. The samples were treated to tempering to around 250 °C, 350 °C, 450 °C and were named as T1, T2 and T3 respectively. Tempering treatments were carried out to maintain stability with ductility and brittleness in martensitic stainless steel material. The transformation changes from martensitic phase to austenitic phase were obtained on the specimens. Wear tests were carried out using pin-on-disc equipment to examine the wear behavior. An untreated sample is kept aside for comparison of results with treated samples. Further, samples were examined using SEM Scanning Electron Microscope. The microstructures of treated samples were compared with untreated samples. The best specimen is chosen for the application were the material will withstand variable speed and load.