Regular Article

The effect of shot peening and precipitation hardening on the wear behavior of high manganese austenitic steels

¹ Department of Mechanical Engineering, Tiran Branch, Islamic Azad University, Isfahan, Iran
² Department of Materials Engineering, Sirjan Branch, Islamic Azad University, Sirjan, Iran

^* Corresponding author: K_amini@iautiran.ac.ir

Received: 4 December 2016
Received in final form: 1 June 2017

Abstract

In this research, the effect of applied work hardening using shot peening and precipitation hardening processes on the hardness and wear behavior of high-Mn austenitic steel has been evaluated. In this regard, after the casting process, the castings were held under solution annealing at 1100 °C for 2 h and then quenched. Then, one of the samples was shot-peened for 30 min and the other sample was shot-peened for 30 min after precipitation hardening at 550 °C for 2 hours and quenching in water. Hardness test and wear test via dry sand rubber wheel were carried out for the three samples. The results showed that the hardness from 290 HV0.5 for the solution-annealed sample reached 698 HV0.5 for the sample shot-peened for 30 min. This increase occurred because of work hardening caused by shot peening in the presence of Mn. In addition, in the precipitation-hardened sample, the hardness after precipitation hardening process and both precipitation hardening process and shot peening for 2 hours reached 380 HV0.5 and 730 HV0.5, respectively. The wear resistance increased by 40% in the shot-peened sample and 58% in both precipitation-hardened and shot-peened sample in comparison to the solution-annealed sample. Carbide precipitation in the matrix and work hardening caused by shot peening contributed to the improvement of both hardness and wear resistance in the precipitation-hardened and shot-peened sample. The wear surface showed abrasive wear mechanism. Moreover, the higher the hardness was, the fewer were the number and depth of the grooves.