Optimization of process parameters for shielded metal arc welding for ASTM A 572 grade 50

Abstract

The quality of a weld significantly depends on the mechanical characteristics of the welded joint, the welding process, and its associated input parameters. Insufficient parameter values can lead to welding defects and distortion that adversely affect mechanical properties. Consequently, carefully selecting appropriate parameters at an optimal level becomes crucial to mitigate defects, enhance productivity, and achieve desirable mechanical attributes in shielded metal arc welding (SMAW). This study explores optimizing SMAW parameters for ASTM A572 Grade 50 steel joints, vital in heavy machinery. Using Taguchi L16 array, parameters were varied across four levels. Grey relational and principal component analysis guided optimization. Results reveal groove angle's impact on tensile strength, electrode diameter on impact strength, and welding current on hardness and angular distortion. Optimal parameters were: 160 A welding current, 60° groove angle, 3.25 electrode diameter, 3 mm root gap, and 3 mm root face. Implementation of optimal parameters led to significant improvements: 10.53% higher tensile strength, 14.28% increased impact toughness, 8.55% reduced hardness, and a remarkable 33.33% decrease in angular distortion.