Ni-Fe-C ALLOY EFFECT ON η PHASE FORMED DURING TIG WELDING OF WC-Co WITH 45 STEEL

摘要

＜正＞Ni-Fe-C filler metal based on WC-30Co/Ni-Fe-C/45 steel is developed using TIG welding method. The weld joints are studied by means of optical microscope, SEM, EPMA, X-rays and micro hardness test etc. The results show that the weld joints of WC-30Co and 45 steel can be obtained by TIG welding using Ni-Fe-C alloys as filler metals. The harmful η phase formed in the joints is M6C, M12C type carbides. The poor carbon content of the W-Co-C system resulted from the carbon diffusion and the high ingredient Fe are the two vital factors inducing to η phase formation. It could be restricted by the addition of carbon element into Ni-Fe alloys.