Regular Article

Investigation of electrode pressure parameter on mechanical properties and microstructural characteristics of spot welded DP800 steel joints

¹ Department of Mechanical Engineering, Meenakshi Ramaswamy Engineering College, Thathanur 621804, India
² Centre for Materials Joining and Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar 608 002, India
³ Central Library, Alagppa University, Karaikudi 630 003, India

^* e-mail: rajachozhan93@gamil.com

Received: 4 December 2021
Accepted: 2 February 2022

Abstract

This investigation details the effect of electrode pressure on mechanical behavior and microstructural characteristics of Resistance Spot Welded (RSW) DP800 steel joints. The joints were fabricated for the range of 0.35–0.45 MPa electrode pressure. Tensile Shear Fracture Load (TSFL) and Cross Tensile Shear Fracture Load (CTSFL) recorded a maximum of 20.06 kN and 16.53 kN respectively for the joints. The hardness map revealed that the heat affected zone has lower hardness among other zones due to the presence of coarser grains. The Nugget Zone (NZ) microstructure consists of lath/needle-like martensite structures. The confirmed crystallography planes and intermetallics in the weld and nearer regions correspond to [101]_α/, [200]_γ, and cementite (Fe₃C), manganese carbide (Mn₃C). The above results concluded that the electrode pressure played a significant role in controlling the quality and integrity of the RSW joints.