Prediction and optimisation of parameters influencing cold crack in gas metal arc welding of hsla 950a

Abstract

High strength low alloy steel (HSLA) has been in use in workshops since the 1980s. Cold cracking is a common problem associated with welding of HSLA steels. Hydrogen-induced cold cracking (HICC) is associated with the Heat Affected Zone (HAZ) of HSLA weld metal. Various researchers aim the improvement of the weldability of structural steel. HICC occurs by a complex interaction of the diffusible hydrogen content, residual stress, and susceptible microstructure. It is thus becoming mandatory to have a novel method of welding to minimize the effects of HICC. Cold cracking is limited to steels and is associated with the formation of martensite as the weld cools. The cracking occurs in the heat-affected zone as well as weld metal. The microstructural constituent of the weld metal plays a significant role in determining the cold crack susceptibility of the weld metal. Hence an attempt has been made to change the microstructure having high resistance to cold cracking. Acicular ferrite microstructure in the weld metal increases the cold cracking strength of the welded joint. newline