Technology Optimization Analysis of Three-Roll Rotary Piercing Process for Seamless Steel Pipe

A three-roll rotary piercing process (TRPP) with severe plastic deformation was conducted to fabricate stainless steel seamless tubes with high mechanical properties. To address production issues such as front stuck (FS) where the front end of the tube blank cannot be accessed, back stuck (BS) where the back end of the tube blank cannot be penetrated and steel-heaping, the process parameters were optimized through simulation and testing in this study. Additionally, a novel structure for the three-roll piercing machine was designed and developed. The changes in roll feed angle and plug advance were systematically analyzed for defects in the tubular billet. Numerical simulations of the TRPP were performed using commercially available Finite Element Method (FEM) software (Simufact Forming) to analyze the stress, strain, temperature, friction stress and contact pressure distributions in the pierced tubes. Experimental analysis was conducted on seamless tubes with different diameter defects, leading to the discovery of optimal rules. Based on the experimental and numerical investigations, it was found that optimizing plug advance and roll feed angle can enhance the forming quality of the tubes.