Nitrogen absorption and desorption by steels during arc and laser welding

Abstract

There are many occasions during the fusion welding process where a molten weld metal is isolated from the air by means of a shielding gas. If air is enveloped into the welding atmosphere and the molten weld metal actively reacts with the gas, the absorbed gas may affect various weld zone properties. Hydrogen, nitrogen and oxygen are considered typical examples of such gases. They are all key gaseous elements which affect weld metal properties. The focus of this article is the reaction of nitrogen gas with steel weld metal and a description is provided of nitrogen absorption and desorption by steel weld metal during the arc and laser welding processes.