基于损伤因子优化变形参数的超细晶管斜轧穿孔工艺

To make full use of the Mannesmann effect to improve the penetration, taking 45 steel as the research object, with the help of rigid-plastic finite element simulation technology, the influence law of deformation parameters on the damage factor was revealed through the crack initiation control model based on the Oyane damage criterion. The results show that along the forward direction of rolled piece, the damage factor increases with the increase of plastic deformation during the cross rolling of solid bar with tapered roller, and then decreases with the decrease of plastic deformation degree. The damage factor increases gradually from the edge to the center of the blank. The change rule of damage factor during cross rolling piercing of hollow tube is similar to solid bar with tapered roller. The optimized parameters are as follows: the feeding angle of 14°, the rolling angle of 13°, the rolling speed of 50 r·min^-1, the diameter reduction rate of 17%, the rolling temperature of 1000 ℃, and the pre-plug reduction rate of 12%. The shape of the plug is determined. An ultra-fine-grained tube with outer diameter of (Φ66. 2±0. 1986) mm, wall thickness of (6. 0±0. 126) mm and diameter-thickness ratio of 11 is prepared, and the grain size is refined from 29 μm (7 grade grain size) to 9. 8 μm (10 grade grain size), the tensile strength and elongation increases by 9. 0% and 17. 9%, respectively.