Performance characterization studies of SA 515 GR 70 carbon steel welds by alternating shielding gases using GMAW process

Abstract

Use of SA515 Grade 70 carbon steel in high-temperature components newlinesuch as boiler pressure vessels, furnaces, and coils is common. newlineConventionally CO2 is used as shielding gas to weld carbon steel by GMAW newline(Gas Metal Arc Welding). Eventually, spatters that appear in the weld lead to newlineless arc stability. In enhancing the efficiency of the conventional Gas Metal newlineArc Welding process, two shielding gases, namely Argon and CO2, are newlineutilized. These gases are independently supplied to the GMAW torch through newlinea gas alternator unit developed by the Welding Research Institute (WRI) and newlineBharat Heavy Electricals Limited (BHEL) in Trichy, Tamil Nadu, India. The newlineflow and the frequency of the shielding gases are predetermined by the flow newlinemeter and alternator, respectively. The novel process paved the way for the newlinedesired transient arc characteristics ensuring weld quality. Alternate shielding newlinegases generate periodic variations in weld-pool dynamics and impact weld newlinequality. Alternate shielding resulted in efficient shielding and improved the newlinemetallurgical and mechanical properties of the weld metal. The main newlineobjectives of this res newline