马氏体/贝氏体异种耐热钢焊接接头的力学性能及界面失效

MECHANICAL PROPERTIES AND INTERFACICAL FAILURE OF DISSIMILAR WELDED JOINT BETWEEN MARTENSITE AND BAINITE HEAT-RESISTANT STEEL

采用脉冲氩弧焊接工艺、高温加速模拟工况、高温持久、常温力学性能试验研究了不同焊缝强度匹配条件下,马氏体耐热钢9Cr1MoVNbN与贝氏体耐热钢12Cr2MoWVTiB异种钢焊接接头的力学性能、高温强度、蠕变损伤及界面破坏特征。研究结果表明,焊前预热250℃,焊后回火750℃×1 h条件下,加速模拟运行500h、1 000 h、1 500 h后低匹配焊接接头的界面蠕变损伤较严重,力学性能下降明显,失效倾向较大;而中匹配接头的蠕变损伤及失效倾向较小,中匹配与低匹配接头的持久强度比较接近:而高匹配接头的持久强度最低。因此,对于9Cr1MoVNbN/12Cr2MoWVTiB异种钢焊接接头采用中匹配比较合适。

The mechanical properties , creep rupture strength , creep damage and characteristics of interfacial failure of dissimilar welded joint between martensite (9CrlMoVNbN) and bainite steel (12Cr2MoWVTiB) are investigated by means of argon gas shielded tungsten pulsed arc welding, high temperature accelerated simulation, creep rupture, mechanical properties test. The research results indicate that the interfacial creep damage of overmatched and undermatched welded joint is serious, and the reductions of mechanical properties are obvious, the failure tendencies are higher than that of medium welded joint. The creep rupture strength of medium matched joint is almost the same as that of undermatched joint, and the creep rupture strength overmatched joint is the least one, therefore, it is reasonable that the medium matched is used for dissimilar welded joint between martensite and bainite steel.