Wear resistance of Fe-Cr-C hardfacing deposited by flux-core double-wire GTAW in rubber wheel abrasion test

Abstract

The wear resistance of metals can be improved by using the hardfacing technique. Different processes can produce it with the desirable microstructures and mechanical properties. This study presents an original method, flux-core-double-wire of gas-shielded tungsten arc welding, in which wires of different compositions are used simultaneously to obtain different microstructures. The deposition was controlled through the following parameters: welding speed, deposition current, standoff distance, torch angle, and pulse frequency of wire feed. Four coatings were deposited on AISI 1020 steel substrate by combining the cored wires: Fe–Cr–C, Fe– Cr–C–Nb, Fe–Cr–C–Mo–Nb, and Fe–Cr–C–Mo–Ti. The combination of these wires resulted in a hypoeutectic microstructure with niobium and titanium carbides, with an average hardness of 650 HV0.3. The hypereutectic microstructures were formed by different niobium contents, with a microhardness range from 820 to 1,020 HV0.3. The performance of the hardfacing was evaluated in the rubber wheel abrasion test described by ASTM G65, Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Wheel Apparatus (Superseded), procedure B. The results revealed that the carbide cracking distinguished the wear resistance, and the hardness was not enough to separate the wear behavior. Still, the volume fraction of carbides was a decisive microstructural parameter.