Microstructure and wear characteristics of hypoeutectic, eutectic and hypereutectic (Cr,Fe) 23C 6 carbides in hardfacing alloys

Abstract

This study investigates the microstructure and wear characteristics of hypoeutectic, eutectic and hypereutectic (Cr,Fe) 23C 6 carbides in hardfacing alloy cladding by using gas tungsten arc welding (GTAW). Chromium and graphite alloy fillers were used to clad ASTM A36 steel substrates. These coatings were specially designed to vary the size and proportion of the (Cr,Fe) 23C 6 carbides that are present in the microstructure at room temperature. Depending on the amount of graphite used in the alloy filler, a hypoeutectic, eutectic or hypereutectic microstructure was obtained on the coated surface. The wear behavior indicated that the abrasive wear resistance is not only simply related to the hardness of the deposit but that it is also determined by the carbides and matrix structure of the coating. The hypereutectic carbides have the largest (Cr,Fe) 23C 6 carbide content and the maximum hardness; however, they show the worst wear resistance due to the large particles were dug out during wearing. ©2007 The Japan Institute of Metals.