Investigating the effect of holding duration at a deep cryogenic temperature on the wear behavior of DIN 1.2080 (D3) tool steel

¹ Department of Mechanical Engineering, Tiran Branch, Islamic Azad University, Isfahan, Iran
e-mail: k_amini@iautiran.ac.ir
² Department of Materials Science and Engineering, Shiraz Branch, Islamic Azad University, Shiraz, Iran
³ Department of Materials Science and Engineering, Shiraz University, Shiraz, Iran

Received: 21 December 2014
Accepted: 29 May 2015

Abstract

This work focused on the effect of the holding time in a deep cryogenic heat treatment on the wear behavior, microstructural changes, retained austenite percentage and microhardness of 1.2080(D3) tool steel. These analyses were performed via optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and energy dispersion spectroscopy (EDS) to study the microstructure. A pin-on-disk wear testing machine was employed to investigate the wear behavior. The microhardness changes were measured by KOPA machine. It was shown that the deep cryogenic heat treatment eliminates retained austenite and makes a more uniform carbide distribution with higher percentages. Furthermore, some new nano-sized carbides form during the deep cryogenic treatment, thereby increasing the hardness and improving the wear behavior of the samples. It was also observed that the deep cryogenic heat treatment improves the wear behavior and microhardness of samples with an increase in the holding duration up to an optimum value: beyond that duration, the wear resistance and microhardness decreases to a specific value, and changed specifically at longer holding durations. It was also observed that the predominant wear mechanism was a combination of adhesive and tribochemical wear.