Friction and Wear Behaviors of Fe-19Cr-15Mn-0.66N Steel at High Temperature

Shaolong Sheng,Jingyong Li,Huiling Zhou,Hongtao Yuan,Yanxin Qiao,Xiaojing Wang,Jiasheng Zou,Zhenguang Liu,Lanlan Yang,Jian Chen,Zhibin Zheng,Dongpeng Wang

doi:10.3390/coatings11111285

Abstract

The friction and wear behaviors of Fe-19Cr-15Mn-0.66N steel were investigated under applied loads of 5 N and 15 N at the wear-testing temperatures of 300 °C and 500 °C using a ball-on-disc tribometer. The wear tracks were evaluated by scanning electron microscopy (SEM) and laser scanning confocal microscopy (LSCM) to reveal the variation in morphologies. Energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were used to determine the components of oxide layers formed on wear surfaces. The results demonstrated that the oxide layers are favorable for obtaining a low friction coefficient under all conditions. The average friction coefficient decreased with increasing load at 300 °C, while it increased with the increase in applied load at 500 °C. At 300 °C, severe abrasive wear characterized by grooves resulted in a high friction coefficient with 5 N applied, whereas the formation of a denser oxide layer consisting of Cr2O3, FeCr2O4, Fe2O3, etc., and the increased hardness caused by work hardening led to a decrease in friction characterized by mild adhesive wear. At 500 °C, the transformation of Fe2O3 to the relatively softer Fe3O4 and the high production of lubricating Mn2O3 resulted in a minimum average friction coefficient (0.34) when 5 N was applied. However, the softening caused by high temperature weakened the hardening effect, and thus the friction coefficient increased with 15 N applied at 500 °C.

Highlights

High-nitrogen austenitic stainless steel (HNSS) can be used for non-magnetic drill collars in oil exploitation, bearing steels for automobile industry, and many other applications due to its excellent properties, i.e., high strength, good ductility, and superior corrosion resistance [1,2,3,4,5,6]
It can be seen from the results of the friction coefficient that there was no significant fluctuation after 400 s (Figure 1), indicating that the oxides formed on the wear track surface play a crucial role in the wear process
The friction and wear behaviors of the Fe-19Cr-15Mn-0.66N HNSS at high temperature were tested under different conditions with different loads and temperatures, and the conclusions can be drawn as follows: (1)

Summary

Introduction

High-nitrogen austenitic stainless steel (HNSS) can be used for non-magnetic drill collars in oil exploitation, bearing steels for automobile industry, and many other applications due to its excellent properties, i.e., high strength, good ductility, and superior corrosion resistance [1,2,3,4,5,6]. Metallic materials can be oxidized or softened at high temperature, which plays a significant role, causing a change in overall friction behavior [16]. This is because oxides can reduce metal wear by reducing or eliminating metal–metal contact, allowing a transition from severe to mild wear [17]. The high-temperature wear mechanism of 445 stainless steel was studied, and the Crrich oxide scale was able to stabilize the friction coefficient and reduce the wear rate [24]. There is a lack of research on the tribological properties of HNSS at high temperatures, and the synergistic effects of load and temperature on the wear mechanisms of HNSS need to be further studied. The microstructure and tribological properties of the samples were systematically characterized and analyzed

Experimental Details

N 15 N

Microstructure Characteristics of the Wear Tracks

Summary