Improvement in Tribological Properties of Cr12MoV Cold Work Die Steel by HVOF Sprayed WC-CoCr Cermet Coatings

Sheng Hong,Jinran Lin,Yuping Wu,Bo Wang

doi:10.3390/coatings9120825

Sheng Hong, Jinran Lin + Show 2 more

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https://doi.org/10.3390/coatings9120825

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Journal: Coatings	Publication Date: Dec 4, 2019
Citations: 16	License type: CC BY 4.0

Affiliation: Hohai University, Nanjing Agricultural University

Abstract

The main objective of this study was to develop an efficient coating to increase the wear resistance of cold work die steel at different temperatures. The microstructures of high-velocity oxygen-fuel (HVOF)-sprayed WC-CoCr coatings were evaluated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of temperature on the tribological properties of the coatings and the reference Cr12MoV cold work die steel were both investigated by SEM, environmental scanning electron microscopy (ESEM), X-ray diffraction (XRD), and a pin-on-disk high-temperature tribometer. The coating exhibited a significantly lower wear rate and superior resistance against sliding wear as compared to the die steel at each test temperature, whereas no major differences in terms of the variation tendency of the friction coefficient as a function of temperature were observed in both the coatings and the die steels. These can be attributed to the presence of nanocrystalline grains and the fcc-Co phase in the coating. Moreover, the wear mechanisms of the coatings and the die steels were compared and discussed. The coating presented herein provided a competitive approach to improve the sliding wear performance of cold work die steel.

Highlights

Friction, as one of the major sources of energy dissipation between the contact surfaces, is the main cause of wear and is a common phenomenon in many industries such as rolling, packaging and mineral processing, where cold work die steel is widely used [1]
The present study aimed to discover the effect of temperature on the sliding wear behavior of the WC-CoCr coating and to illustrate the dry sliding wear mechanisms at different temperatures in relation to the microstructures
The experiments were conducted by using high-velocity oxygen-fuel (HVOF) spraying to fabricate a WC-CoCr cermet coating to improve the surface tribological properties of Cr12MoV cold work die steel

Summary

Introduction

As one of the major sources of energy dissipation between the contact surfaces, is the main cause of wear and is a common phenomenon in many industries such as rolling, packaging and mineral processing, where cold work die steel is widely used [1]. In order to meet these requirements, various metals [2], ceramics [3], and surface materials [4,5] with a unique combination of corrosion and wear resistance and high-temperature stability are being investigated and considered as effective methods to tailor the properties of engineering components [4,5,6,7,8]. Surface technologies have been applied to a wide variety of materials without the necessity of using expensive and time-consuming heat treatments or alloying techniques, which can significantly change surface properties and may beneficially enhance the wear resistance of engineering materials [6,7]. As one of the most commonly-used surface coating technologies, thermal spraying has played a major role in the development of solutions for new technological problems as well as in the understanding of friction and wear mechanisms [8,9,10].

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