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核反应堆压力容器接管安全端异种金属焊接接头在服役中通常会产生高温高压水环境中的应力腐蚀裂纹扩展。目前减轻和修复这种裂纹的技术是在安全端管接头外表面堆焊一层更抗腐蚀的镍基合金(Alloy52M)材料。本文通过三维结构的有限元断裂力学分析,计算得到了堆焊修复结构的“先漏后断”(Leak-before-break,LBB)曲线和韧带失稳线,并分析了堆焊层厚度对LBB安全边际的影响。结果表明,堆焊修复后结构的LBB曲线和韧带失稳线在没有堆焊层结构的曲线上方,且随堆焊层厚度的增加,LBB曲线和韧带失稳线上移,表明堆焊修复及堆焊层厚度的增加使安全端结构的LBB安全边际增大。
Nuclear reactor pressure vessels take over safety-end dissimilar metal welded joints that typically experience stress corrosion crack propagation in high temperature and pressure water environments during service. The current technique to mitigate and repair this type of crack is to overlay a more corrosion resistant nickel-based alloy (Alloy52M) material on the outer surface of the safety end fitting. In this paper, the “Leak-before-break” (LBB) curve and the ligament failure curve of the overlay repaired structure are calculated through the finite element fracture mechanics analysis of the three-dimensional structure. The thickness of the overlay Impact on LBB Security Margin. The results show that the LBB curve and the ligament instability curve of the structure after surfacing welding are above the curve without surfacing layer structure, and the LBB curve and the ligament instability line go up with the increase of the thickness of the surfacing layer, Increasing the thickness of the overlay increases the LBB safety margin of the safety end structure.