Research on Forging Process of Segmented Sleeve of High-Pressure Grinding Roll

The segmented sleeve is a critical load-bearing and wear-resistant component of high-pressure grinding rolls (HPGRs), whose forging quality directly governs the equipment’s operational stability, transmission efficiency and service life. 34CrNi3MoVA steel is widely used for such heavy-duty components owing to its high strength, excellent toughness and outstanding hardenability. However, the large cross-section and irregular fan-shaped segmented geometry of the part pose formidable challenges to conventional forging processes, and dedicated mature forming routes for such components remain insufficiently studied. In this work, aiming to address the drawbacks of the current industrial manufacturing route, where segmented sleeves are fabricated by heavy mechanical machining from large free-forged blanks, three forging schemes—single-cavity die forging, two-cavity die forging, and a newly developed multi-step incremental die forging—were systematically designed for 34CrNi3MoVA steel segmented sleeves. Thermo-mechanical coupled finite element simulations were performed to compare and analyze the metal filling behavior, temperature field distribution, effective strain characteristics and forming load of each process. The optimal process was further verified through industrial production trials. The results show that the two-cavity die forging is engineeringly unfeasible due to its excessive peak load of 213,925 t, far beyond the capacity of mainstream forging presses. The single-cavity die forging, with a peak load of 70,824.8 t, suffers from severely insufficient core forging penetration, with over 60% of the forging volume below the critical strain threshold. In contrast, the multi-step incremental die forging reduces the peak load to only 6620.67 t, which is well compatible with conventional industrial forging equipment. It also achieves full through-thickness forging with uniformly distributed strain and temperature fields, effectively eliminating low-strain dead zones in the core. The industrial trial results agree well with the simulation predictions, and the forgings present satisfactory dimensional accuracy and forming quality without macroscopic defects. This study provides a practical and cost-effective process solution for the fabrication of large-scale HPGR segmented sleeves, with important engineering application value.