Method to eliminate weld solidification cracking of 312 stainless steel overlay and to minimize the overlay's thermal expansion mismatch with carbon steel or low alloy steel substrate

Abstract

A method for applying a stainless steel weld overlay on a substrate, e.g., a carbon steel or low alloy steel, uses an arc welding process. The process includes welding a stainless steel weld overlay onto the substrate using a shielding gas mixture including greater than 2% nitrogen by volume with balance being an inert gas or a mixture of inert gases. The nitrogen is of a sufficient concentration so as to eliminate solidification cracking in the weld overlay. In addition, the nitrogen may help to eliminate a mismatch in me coefficient of thermal expansion between the weld overlay and the substrate. Furthermore, if the weld overlay comprises only a single layer, the nitrogen concentration in the shielding gas mixture may be less than 2%.

Dependencies are inferred from the claim text.