P92钢焊接接头蠕变损伤与裂纹扩展数值模拟

高温焊接接头由于蠕变损伤而提前失效的案例频频发生，准确预测焊接接头的蠕变损伤和裂纹扩展行为对于保证高温装备的结构完整性具有重要意义.文中基于延性耗竭模型并结合有限元方法，考察了结构因素对厚壁圆管焊接接头蠕变失效行为的影响.结果表明，蠕变裂纹萌生/扩展行为受热影响区宽度影响，细晶热影响区宽度对蠕变裂纹的萌生时间影响不大，但会改变裂纹萌生位置；相比之下，粗晶热影响区的宽度变化对裂纹萌生时间影响略大.不同坡口形式展现出不同的裂纹萌生/扩展行为，而X形坡口是四种坡口形式中的较优选择.

Numerical simulations of creep damage and crack growth in P92 steel welded joints

Premature failures caused by creep damage occurred frequently in high-temperature steam pipes welded joints. Therefore, it is of great significance to predict the evolution of creep damage and crack growth behaviors in order to ensure structural integrity of high-temperature equipment. This paper investigated the effects of structural factors to creep failure behaviors of thick-wall welded joints using finite element methods based on a ductility exhaustion model. It is shown that the width of heat affected zone would affect the creep crack initiation and growth behavior. The width of fine grain heat affected zone (FGHAZ) had little effect on the crack initial time, but it would change the initial location of the crack. In comparison, the width of coarse grain heat affected zone (CGHAZ) had slightly larger effect on the crack initial time. Four welded joints with different groove types exhibited different crack initiation and growth behaviors. Double V type groove was considered to be an optimal choice in four groove types.