Research on the Effect of Tempering Process on the Microstructure and Mechanical Properties of Low Matching Welded Joints of 45CrNiMoVA Steel
摘要
The microstructure and comprehensive mechanical properties of low-matched welded butt joints of 45CrNiMoVA steel were investigated under different tempering processes. It was found that high-temperature short-time tempering above 550 °C offers clear advantages over medium-temperature tempering below 500 °C. It not only yields welded joints with excellent comprehensive mechanical properties, but also significantly reduces the heat treatment cycle and cost. When the tempering temperature is controlled between 550 and 600 °C, the tensile strength of the welded joint exceeds 1400 MPa. The welding residual stress remains below 200 MPa, and the ductile‑brittle transition temperature is lower than − 60 °C. Such a combination of properties enables an equal‑load design under static load conditions.