空心钢锭空洞缺陷锻合研究

Research on the cavity defect closure of hollow ingot

大型筒形件锻造过程中,利用空心钢锭进行生产相比于传统工艺具有偏析少、材料利用率高、短流程、能耗低等优点。由于空心钢锭铸造时内外同时进行冷却,其最终凝固位置大约在壁厚的1/2处,此处存在的主要缺陷之一为空洞型缺陷。通过Deform-3D数值模拟软件,分析了镦粗、芯轴拔长、马杠扩孔对空心钢锭球形及径向、轴向、切向空洞型缺陷闭合的作用效果和影响规律,镦粗压下量为40%时可以锻合径向空洞缺陷但不能锻合轴向空洞缺陷,并对径向和轴向空洞缺陷闭合进行了实验验证。研究表明,空心钢锭制坯工艺可不选用镦粗,直接进行拔长或扩孔即可避免空洞缺陷的产生。

During the forging of large cylinder, the production using hollow steel ingot has the advantages of less segregation, higher material utilization rate, shorter production cycle and lower energy consumption compared with the traditional process. Both the inside and outside are cooling at the same time when hollow steel ingot is casted, and the position of the final solidification location is about the middle of the hollow steel ingot, while one of the main defects is cavity defect there. With the numerical simulation software of Deform -3D, the deformation effect and influence law were studied including upsetting, drawing and enlarging in the process of hollow ingot＇s spherical, radial, axial and tangential cavity defect closure. Under 40% deformation of upsetting, the radial cavity defect could be closed but the axial cavity defect could not, and the experimental verifications for radial and axial cavity defects closure were done. The research shows that drawing or enlarging can be conducted directly without upsetting for the hollow steel ingot blocking process, which avoids the generation of cavity defect.