The examination of microstructural and mechanical properties of friction stir welded XPF800 steel

This study investigates the friction stir welding properties and resulting microstructural and mechanical properties of XPF800 steel, which is commonly used in automotive chassis and suspension components. The welding parameters were optimized with a tungsten carbide (WC) tool at a downforce of 11 kN, traverse speed of 95 mm/min, and rotating speed of 750 rpm. Microstructural analysis was conducted using scanning electron microscopy (SEM), optical microscopy (OM), and Energy Dispersive X-ray Spectrometry (EDS). Mechanical properties were evaluated through tensile, Charpy impact, and microhardness tests. Results showed that acicular ferrite formed in the stir zone, contributing to an increase in strength, with a maximum hardness of approximately 350 HV 0.1 . However, the heat affected zone (HAZ) experienced softening, resulting in a decrease in both tensile strength and hardness by approximately 8% and 20%, respectively, compared to the base material.