Investigations on microstructural and mechanical properties of BSK 46 steel weldments

Abstract

BSK 46 is a low alloy structural steel with excellent mechanical and corrosion properties and is widely used in many applications, including tipper bodies of heavy-duty trucks. Optimizing the welding parameters to reduce defects and improve productivity is critical for the users. The present work addresses optimizing the welding process parameters to improve productivity with adequate weld quality during the pulsed gas metal arc welding (P-GMAW) process. Three BSK 46 weldments (weld-1, weld-2 and weld-3) were fabricated by varying the root gap, root face, filler pass and heat input. The metallographic and mechanical characterization of P-GMAW weldments were done through microstructures, Vickers micro-hardness, transverse tensile strength, Charpy toughness and three-point bend test. Subsequently, a correlation has been developed between the microstructural features and mechanical properties of the weld joints. The hardness was found to be incremental in nature from the base metal to the fusion zone. Maximum hardness of 215.81  ±  10 HV was observed in the weld-3 fusion zone. Tensile test results reveal that weld-3 weldments exhibit a higher tensile strength of 547.48  ±  2 MPa than weld-1 (537.46  ±  7 MPa) and weld-2 (533.67  ±  9 MPa) weldments. Maximum impact toughness of 136.33  ±  14 J was observed in the weld-3 weldments. Post-bend testing showed no cracks on the weld surfaces, indicating defect-free weld joints with good ductility. It is observed that weld-3 showed relatively better mechanical properties than weld-1 and weld-2 in lesser welding time and lower welding cost