核电用SA508-3钢大型锻件的内部裂纹缺陷分析及工艺优化  

Internal crack defect analysis and process optimization on heavy forgings steel SA508-3 used for unclear power

作　　者：门正兴[1] 马亚鑫 周杰[2] 岳太文[1] 

机构地区：[1]成都航空职业技术学院机电工程学院,四川成都610021 [2]重庆大学材料科学与工程学院,重庆400044

出　　处：《锻压技术》2017年第8期1-6,共6页Forging & Stamping Technology

基　　金：国家自然科学基金资助项目(51275543);四川省教育厅科研资助项目(17ZB0035)

摘　　要：SA508-3钢是目前大型核反应堆压力容器的主要材料,从材料成形角度提高SA508-3钢大型锻件整体性能从而提高零件安全性是大型铸锻件研究的重要方向。通过对传统锥板镦粗+平板旋转展平工艺成形的SA508-3钢大型锻件的超声波探伤密集型缺陷进行失效分析,得到缺陷为呈断续锯齿状的裂纹缺陷,缺陷产生的原因与微观偏析带引起的金属材料组织和性能不均有关。采用数值模拟方法,对传统工艺与锥板镦粗+胎模旋转展平新工艺进行比较分析。结果表明,采用新工艺时,锻件内部金属在三向压应力下发生大变形,可避免新裂纹产生,有利于已有闭合裂纹的焊合,锻件组织更加均匀。实际生产过程中,该方法可有效减少SA508-3钢大型锻件中的密集型裂纹缺陷。Steel SA508-3 is the main material of large-scale nuclear reactor pressure vessel. Improving the overall forming performance of large forgings of steel SA508-3 in order to improving the security of part is one of the most important research directions in large-scale casting and forging industry. For large forgings of steel SA508-3 formed by conventional cone plate upsetting and flat plate rotate flattening process,the failure analysis of intensive internal defects was performed by ultrasonic inspection,and the intensive defects with intermittent serrated cracks were obtained resulting from the non-uniform microstructure and performance of metal material caused by the microscopic segregation. Then,a new process of the coneplate upsetting and rotate flattening in the die was compared with the conventional process by the finite element method. The result shows that large deformations under three-dimensional compressive stress state are produced in the forging,which is beneficial to avoid new cracks,weld the existing close cracks and homogeneous microstructure in the large forgings.Thus,in the actual production process,the above new process can effectively reduce the intensive crack defects in the large forgings of steel SA508-3.

关 键 词：SA508-3钢 大型锻件 裂纹缺陷 偏析 展平 

分 类 号：TG316[金属学及工艺—金属压力加工] TM623.2[电气工程—电力系统及自动化]