Analysis of Precision Forging Process and Die Design for a Multi-Step Double-Pass Connection Joint

The study focuses on a multi-step double-pass connecting joint to address issues such as incomplete forming, partial punching, and low dimensional accuracy in its hot forging process. Numerical simulation experiments were conducted using the rigid-plastic finite element method and Deform-3D software to simulate the metal flow and temperature evolution of various forming schemes. The analysis evaluated forging filling quality, forming load, and temperature differences, providing optimization suggestions for process parameters. Based on the results, an optimal multi-station hot forging process scheme was selected, followed by the design and trial production of a three-station mold. In the multi-station forming scheme, metal flow was normal, with no abnormalities such as convection or backflow. Node distribution was uniform, and no underfilling occurred. A comparison of the two schemes revealed that the two-station final forging forming load was 3430.69 kN, with a temperature difference of 227 °C, while the three-station final forging forming load was 2909.96 kN, with a temperature difference of 123 °C. The three-station scheme demonstrated lower forming loads, smaller internal temperature differences, reduced residual stress after cooling, and a lower risk of cracking. Trial production using the three-station process confirmed that the forgings formed well, exhibited clear punching, and met the precision dimensional requirements.