Abrasive Wear Behavious of Iron Based Hard Serfacing Alloy Coatings Developed by Welding

Abstract

The influence of the welding process and post-welding heat treatment on the abrasive wear resistance of iron based hardfacing overlays (Fe–6Cr–0.5C) is reported. Overlays were deposited by shielded metal arc (SMA) and tungsten inert gas (TIG) welding processes on structural steel using a commercially available surfacing electrode (BOR-C) 3.15 mm in diameter. Overlays were deposited by the SMA welding process using 250 A dc (straight and reverse polarity) at a constant welding speed ∼15 cm min^–1. The abrasive wear resistance of overlays in as welded and heat treated conditions was tested on a pin on disc system against 300 grade waterproof SiC polishing paper at different normal loads (1–5 N). Optical microscopy was used to study the microstructure of the overlays. SEM study of the wear surfaces was done to analyse the wear mechanism. It was found that the wear resistance of the coating produced by TIG welding is better than that of coatings deposited by SMA welding. The hardness of the coating adjacent to the interface is found to be comparatively lower than that away from the interface. Post-weld heat treatment improves the abrasive wear resistance. SE/S278