Background

Hot work die steel has broad application prospects in fields such as hot forging dies, hot extrusion dies, die casting molds, and hot upsetting dies, making it an important research subject in die steel.

Purpose

With the increasing market demands for the performance of hot work die steel, there is an urgent need to further enhance its wear resistance and thermal fatigue properties. Alloying and forging are two effective approaches for material modification. To this end, different forging processes were applied to vanadium-containing hot work die steel, investigating the effects of forging techniques on the microstructure, wear resistance, and thermal fatigue properties of 5CrNiMoV, and a comparative analysis was conducted with commercial 5CrNiMo hot work die steel.

Conclusion

The experimental results show that (1) adding vanadium as an alloying element to 5CrNiMo die steel can refine its grain structure, improving its wear resistance and thermal fatigue performance. Forging can further refine the grain structure of the new vanadium-containing hot work die steel 5CrNiMoV sample, further enhancing the wear resistance and thermal fatigue performance of 5CrNiMoV die steel.

(2) Compared to 5CrNiMo mold steel, the vanadium-containing mold steel 5CrNiMoV exhibits a 14.7% reduction in wear volume. After forging, the wear volume of 5CrNiMoV is reduced by 35.3%, demonstrating superior wear resistance.

(3) Compared to 5CrNiMo mold steel, the vanadium-containing mold steel 5CrNiMoV shows a reduction of 2 levels in thermal fatigue crack rating, with a decrease of 28.6%. After forging, the vanadium-containing mold steel 5CrNiMoV exhibits a reduction of 4 levels in thermal fatigue crack rating, with a decrease of 57.1%. The vanadium-containing mold steel 5CrNiMoV demonstrates superior thermal fatigue performance after forging.