INVESTIGATION ON MECHANICAL PROPERTIES AND CORROSION RESISTANCE OF COBALT-BASED ALLOY CLADDING LAYER

摘要

Austenitic stainless steel was cladded with Cobalt-based alloy by means of Tungsten inert gas (TIG) welding to improve the performance of the working parts such as the thrust bearing plates under dynamic loads and corrosive liquid. Specimens were prepared with different welding parameters, namely the cladding current, preheating temperature, inter-layer temperature and post heat treatment temperature, so as to investigate their influence on micro-hardness, as well as tensile and bending strength. It is revealed that the lower welding current coincides with higher micro-hardness as well as tensile and bending strength. The higher inter-layer temperature will result inhigher overlay micro-hardness. The post weld heat treatment temperature influences the bending strength of the overlay weld specimens. In addition, the accumulation of Cr and Ni compounds on weldment surface is found to coincide with higher corrosion resistance in over-layers by means of XRD.