Characterization of Dissimilar Welds of Carbon Steels and Ni-Filler Alloy

A weldment made of two different carbon steel plates using a nickel-based filler alloy was characterized. The studies involved microhardness testing, light optical and scanning electron microscopy, energy-dispersive x-ray spectroscopy and electron backscattered diffraction analyses in selected areas that included the base metal and heat-affected zones. It was found that welding promoted the mixture of the molten liquids from the filler alloy with those from the steel plates yielding to different chemical profiles. Microstructural changes within the steel plates were observed to occur, and these were attributed to the characteristics of the steels. The increase in hardness in the heat-affected zone of one of the steels was detected.