核电站波动管对接焊缝微裂纹分析

Study on mic-cracking in girth weld of connecting pipe used in nuclear power station

针对核电站复合钢波动管对接焊缝所出现的裂纹,从焊接冶金和力学的角度分析了微裂纹的形成。分析指出:奥氏体钢焊缝的导热系数小而线膨胀系数大,凝固过程中收缩量大,波动管的拘束度大,在奥氏体焊缝内形成较大的拉伸力,增加了复合钢波动管焊接的热裂纹敏感性,在波动管焊接施工过程中应采取有效措施防止热裂纹的产生。

Based on welding metallurgy and mechanics theory,the analysis was carried on the cracking in the girth weld of connecting pipe used in nuclear power station.The results show that the weld of austenite steel has larger thermal expansivity and small thermal conductivity leading to more contraction during solidification.The connecting pipe exhibit high restraining and tension stress formed in weld.The hot cracking sensitivity may be increase and the procedure corresponding to prevention should be used in the connecting pipe welding.