Core damage mechanism and effects of shaft parts by warm cross-wedge rolling

Warming rolling is the development direction of CWR (cross-wedge rolling). How to control the core defects is the key to popularize WCWR (warm cross-wedge rolling) technology. In this paper, the 42CrMo shaft part is taken as the research object and a three-dimensional plastic-thermo-mechanical coupling numerical model is established. DEFORM-3D software is used to simulate HCWR (hot cross-wedge rolling) and WCWR. The stress distribution at the symmetrical center is analyzed by clarifying the core damage mechanism of the shaft. The effects of forming angle (alpha), spreading angle (beta), section shrinkage (psi), and rolling temperature (T) on the core quality by WCWR are analyzed. The results show that the core quality with the section shrinkage of 40-60% is better. The core quality is excellent due to the short rolling time and lower transverse stress fluctuation range when the alpha is bigger than 28 degrees, beta is bigger than 8 degrees, and T is bigger than 750 celcius. The rolling experiment was carried out on H630 CWR mill. The results provide a theoretical basis for controlling the core defects and improving the quality of the workpiece.