Evolution of the Fretting Wear Damage of a Complex Phase Compound Layer for a Nitrided High-Carbon High-Chromium Steel

Yong Duan,Shengguan Qu,Siyu Jia,Xiaoqiang Li

doi:10.3390/met10101391

Abstract

In this paper, the X210CrW12 steel was subjected to gas nitriding to obtain a complex phase compound layer with limited porosity. The nitrided layer was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The fretting wear behavior and the evolution of fretting wear damage of the compound layer were studied, and the worn surfaces were characterized by SEM/EDS and 3D optical profilometry. The results indicated that the compound layer showed superior fretting wear resistance and sufficient load-carrying capacity in the low loading case of 35 N, but the fracture of coarse nitrides (transformed primary carbides) was obviously detrimental to wear resistance. For the high loading case of 70 N, the low toughness of the compound layer led to the occurrence of brittle cracks, and the decrease in the thickness of the compound layer due to wear resulted in the cracking and spalling of the compound layer.

Highlights

Gas nitriding, as a typical thermo-chemical surface treatment, is one of the most efficient methods to enhance the surface properties, such as surface hardness, corrosion and wear resistance [1,2,3,4,5,6,7,8].The typical nitrided layer consists of two different structures, known as the compound layer and diffusion layer
The γ0 phase is more ductile than ε phase, but the compound layer consisting of monophase γ0 is usually thin and prone to spalling in heavy conditions due to the extremely hardness differences occurring between the compound layer and diffusion zone [11]
The fretting wear behavior and the evolution of fretting wear damage of the compound layer were studied in detail

Summary

Introduction

As a typical thermo-chemical surface treatment, is one of the most efficient methods to enhance the surface properties, such as surface hardness, corrosion and wear resistance [1,2,3,4,5,6,7,8].The typical nitrided layer consists of two different structures, known as the compound layer and diffusion layer. One type of layer consists of a predominant percentage of ε phase. Such a layer is very porous and its wear resistance is worsened [9,10]. The γ0 phase is more ductile than ε phase, but the compound layer consisting of monophase γ0 is usually thin and prone to spalling in heavy conditions due to the extremely hardness differences occurring between the compound layer and diffusion zone [11]. Investigations show that if the porosity in this type of compound layer can be well controlled, the compound layer with a relative reasonable thickness is very beneficial to the wear and corrosion resistance in many cases [12,13,14,15]. The sliding wear characteristics of this type of compound layer have been extensively studied [4,5,6,7,11,12,13,16,17,18]

Methods

Results

Conclusion