Enhancement of tribological and mechanical properties of TiB2 - Co cladded layer developed by tungsten inert gas cladding on AISI 1020 Steel

Abstract

In the present study, various compositions of TiB2-Co coating were deposited on AISI 1020 mild steel by tungsten inert gas cladding method. In this work, various heat energy of TIG with a fixed travelling speed of 1.5 mm s−1 was used to deposit the coating layer. The aim of this study was to investigate the optimal heat input of TIG to develop a thick layer in terms of coating microstructure and bonding quality. The influence of cobalt addition and current variation on microhardness and wear properties of the cladded layer was also investigated. The metallographic examination and microstructural analysis were investigated by x-ray diffraction, scanning electron microscope (SEM) and energy dispersive spectroscopy. The microhardness and wear rate have been analyzed by Vickers microhardness and dry sliding wear test, respectively. The investigations reveal that the influence of heat input on the wear resistance and hardness of the coated layer was significant. The microhardness value increases with increase in wt.% of TiB2 coating powder when TIG parameter is constant. The microhardness value also increases with decrease in heat input of the TIG when composition of the coating is kept constant. The maximum microhardness value was achieved up to 2563 HV0.1 which was 15 times higher than the substrate hardness value of 170 HV0.1. From the wear test result, it was noticed that the minimum wear rate found was 8.24 × 10–8 g Nm−1 for the coating composed by lower heat input (720 J mm−1) and higher wt.% of TiB2 (90 wt.%).