Structure and Abrasive Wear of Composite HSS M2/WC Coating

S F Gnyusov,V G Durakov,S Yu Tarasov

doi:10.1155/2012/502714

Abstract

Features of phase-structure formation and abrasive wear resistance of composite coatings “WC-M2 steel” worn against tungsten monocarbide have been investigated. It was established that adding 20 wt.% WC to the deposited powder mixture leads to the increase in M6C carbide content. These carbides show a multimodal size distribution consisting of~5.9 μm eutectic carbides along the grain boundaries,~0.25 μm carbides dispersed inside the grains. Also a greater amount of metastable austenite (~88 vol.%) is found. The high abrasive wear resistance of these coatings is provided byγ→α′-martensitic transformation and multimodal size distribution of reinforcing particles.

Highlights

A tendency is to develop and build new equipment at lower costs using sparingly alloyed low carbon steels, which, demand surface hardening either by nitridation or carbonization
Taking it into account we believe that electron beam surfacing in vacuum may be applied for depositing a composite coating after final heat treatment and main mechanical grinding
Wear resistance of the coatings improves with the volume content of the retained austenite because of γ → α strain-induced martensitic transformation and fine carbides precipitated in the matrix’s grains

Summary

Introduction

A tendency is to develop and build new equipment at lower costs using sparingly alloyed low carbon steels, which, demand surface hardening either by nitridation or carbonization. Taking it into account we believe that electron beam surfacing in vacuum may be applied for depositing a composite coating after final heat treatment and main mechanical grinding In modern practice, both hard and superhard composite coatings made of stellite, sormite, or cast tungsten carbide are used to improve wear resistance of working surfaces of machine components. Wear resistance of the coatings improves with the volume content of the retained austenite because of γ → α strain-induced martensitic transformation and fine carbides precipitated in the matrix’s grains. The objective of this work is to study effect of tungsten carbide content in the source mixture on the structure, phase contents, and abrasive wear resistance of HSS M2/WC composite coatings. Some samples were subjected to either single or double tempering carried out at 570±◦C for 1 hour

Figure 1

Results and Discussion

Conclusions