Effect of Pressure on the Linear Friction Welding of a Tool Steel and a Low-Alloy Carbon Steel

Abstract

This study investigates the effect of pressure (burn-off and forging) on the mechanical properties of the joint between a wear-resistant tool steel and a low-alloy steel using linear friction welding. The authors have previously demonstrated the feasibility of joining these dissimilar materials, but the impact of pressure on the mechanical properties of the bimaterial joint remains unclear. To address this, weld samples are prepared using different pressures and are characterized through microstructural analysis, microhardness, tensile testing, and fractography. The results show that the strength of the joint between the wear-resistant tool steel and the low-alloy carbon steel increases as the pressure increases up to a certain point, after which a decrease is observed. The highest joint strength is achieved at a pressure of 360 MPa. The microhardness profile measurement reveals a distinct transition zone at the interface between the two materials, with varying hardness values. The hardness of the low-alloy carbon steel increases near the interface, while that of the wear-resistant tool steel decreases. This transition zone is found to be narrower at higher pressures. Microstructural characterization shows that the grain structure near the interface differs from that of the starting base materials.