Prevent cracking in deposition of Carbon steel on Inconel 625

Abstract

The welding procedure of clad steel, including the deposition of carbon steel on a nickel-base alloy, usually gives unacceptable mechanical properties. Cracks were formed along the type II boundary in the nickel-base alloy pass, and a martensitic layer was formed in the carbon steel pass. In this paper, cracks along the type II boundary were prevented by lowering the martensitic start temperature (TMs) of the martensitic layer. Decreasing of TMs was obtained by two methods: the dilution method and the grain refining method. Three levels of TMs (approximately 350, 200, and 50°C) are obtained. The results showed that cracks along type II boundary were prevented at TMs lower than 200°C; however, the type II boundary itself was prevented at TMs lower than 50°C. Also, post-weld heat treatment was necessary to achieve accepted impact properties.