Preheat Treatment on the Tungsten Carbide Hardfacing: Microstructure Analysis

Abstract

Present study reports the base material preheat treatment effect on microstructure of tungsten carbide (WC) hardfaced carbon steel digester blade which identified as CD blade. Carbon steel blade is located in a digester tank to mix sulphuric acid with ilmenite ore for the process of production. WC hardfacing is deposited on the surface of carbon steel blade to promote its wear resistance as the carbon steel blade is exposed to an abrasive and acidic condition. The influence of base material preheat treatment on microstructure, coating hardness, and elemental composition are the focal point of this work. The effect of base material preheat on hardness value and microstructure of WC hardfacing coating are investigated using hardness test (micro-Vickers) and Scanning electron microscope (SEM) respectively. The base material preheat initiates larger carbide growth in entire coating region and smaller carbide growth in non-carbide region caused by sufficient heat energy. Thus, hardness value of the coating is increased due to uniform distribution of carbides in coating region.