马氏体/贝氏体耐热钢焊接接头的界面蠕变损伤行为

BEHAVIORS OF INTERFACICAL CREEP DAMAGE OF DISSIMILAR WELDED JOINT BETWEEN MARTENSITIC AND BAINITIC HEAT-RESISTANT STEELS

采用脉冲氩弧焊接工艺、高温加速模拟、高温持久实验研究了不同焊缝蠕变强度匹配条件下马氏体耐热钢9Cr1MoVNbN与贝氏体耐热钢12Cr2MOWVTiB异种钢焊接接头的高温强度、界面蠕变损伤及破坏特征．研究结果表明，焊前523K预热、焊后1023K×1h回火条件下，接头的力学性能优异．加速模拟运行500，1000和1500h后低匹配焊接接头的界面蠕变损伤最严重，发生了界面蠕变断裂，早期失效倾向较大；中匹配接头的蠕变损伤最小，仅发现个别孤立蠕变孔洞，早期失效倾向最小，中匹配接头在923K下的持久强度（σ10^5）与低匹配接头比较接近；高匹配接头在923K下的持久强度（σ10^5）最低，蠕变孔洞几乎连成裂纹，蠕变损伤和早期失效较大．因此，对于上述异种钢焊接接头采用中匹配焊缝较为合理．

The creep rupture strength, creep damage and characteristics of interracial failure of dissimilar welded joint between martensitic heat-resistant steel （9Cr1MoVNbN） and bainitic heatresistant steel （12Cr2MoWVTiB） were investigated by means of argon gas shielded tungsten pulsed arc welding, high temperature accelerated simulation and creep rupture test. The research results indicate that the interfacial creep damage of undermatching welded joint is very serious, the interfacial failure occurred and the early failure tendencies are higher than those of overmatching and mediummatching welded joints. The creep damage and early failure tendency of medium-matching joint are lower than those of overmatching and undermatching welded joints, and only isolated holes are found in the test. The creep rupture strength （σl0^5） of medium matching joint is almost the same as that of undermatching joint. The creep rupture strength of overmatching joint is the least one, therefore, using medium-matching joint is reasonable for the dissimilar welded joint between martensitic and bainitic steels.