Optimization of the Die Forging Parameters of 21-4N Heat-Resistant Steel by Processing Maps

The valve is one of the important parts of the engine, and 21-4N is the main material of the engine valve. In the die forging process, accurate process parameters are required to ensure that the engine valve parts that meet the requirements can be obtained. In this paper, the thermal simulation experiments are conducted to obtain stress–strain data of 21-4N heat-resistant steel at a deformation temperature of 1273–1453 K and a deformation rate of 0.01–10 s−1. And hot processing maps are used to optimize the die forging process of 21-4N. The numerical simulation of valve die forging based on the optimized parameters obtained from the thermal processing maps is conducted, and the forming rules are studied. The influence law of die forging temperature, die forging speed, and friction coefficient is analyzed and finally verified in valve processing enterprises.