LIE Home • Issue Contents

Comparative Studies on the Metallurgical and Mechanical Behaviour of CO2 Laser Beam and Pulsed Current Gas Tungsten Arc Welded Stainless Steel
G. Shubham, S.M. Muthu, N. Arivazhagan, K.V. Phani Prabhakar and M. Arivarasu

A comparative assessment of the metallurgical and mechanical properties of AISI 321 stainless steel weldments produced by pulsed current gas tungsten arc welding (PCGTAW) and CO2 laser beam welding (LBW) is conducted and described. Microhardness test data reveal that the hardness value in the weld zone (WZ) is greater for the CO2 LBW weldments (259 HV) compared to PCGTAW weldments (131 HV). The results of the tensile test showed that for the PCGTAW weldments the fracture occurred in the WZ, whereas for CO2 LBW weldments in the base metal (BM). The ultimate tensile strength for CO2 LBW weldments was found to be 640 MPa, whereas for PCGTAW weldments it was 580 MPa. The tensile strength of laser weldment is increased to 4% as compared to the BM. The joint efficiencies of the welding employed by CO2 LBW and PCGTAW processes are found to be 104% and 94%, respectively. It can be observed that laser weldments have better mechanical strength. Fractography analysis confirmed the occurrence of ductile fracture in both the weldments. The residual stress measurements performed on the weldments to ensure the mode of stress revealed the tensile nature of stresses for the PCGTAW sample and compressive nature for the CO2 LBW samples, which support the superior mechanical properties of the latter process.

Keywords: CO2 laser, pulsed current gas tungsten arc, AISI 321 stainless steel, laser beam welding (LBW), pulsed current gas tungsten arc welding (PCGTAW), weld zone (WZ), fusion zone (FZ), heat affected zone (HAZ), microhardness, tensile strength, residual stress, fractography

Full Text (IP)