Transactions of Materials and Heat Treatment

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

Authors： Men Zhengxing Ma Yaxin Zhou Jie Yue Taiwen

Unit： Chengdu Aeronautic Polytechnic Chongqing University

KeyWords： SA508-3 steel heavy forging crack defects segregation flattening

ClassificationCode：TG316.2

year,vol(issue):pagenumber：2017,42(8):1-5

Abstract：

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.

Funds：

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）

门正兴（1980-），男，博士，高级工程师

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