异种铁素体耐热钢接头界面组织及其影响

综述了铁素体与铁素体异种金属焊缝（dissimilar metal welds，DMWs）接头界面组织及其影响。结果表明，在焊后热处理或运行温度下的铁素体钢DMWs接头的不均匀界面组织中，通常会形成脱碳层和增碳层。在铁素体钢DMWs焊接接头界面组织影响因素中，焊缝金属的化学成分有重要影响；焊后热处理规范（温度和时间）、工作温度下运行时间的影响较为突出；焊接工艺参数的影响亦不可忽略。异种钢接头界面处近缝区裂纹的产生，以及接头的蠕变强度随Larson Miller 参数增大而下降等不利影响，均为异种钢界面碳迁移行为所导致。焊缝成分控制法是接头界面组织控制或改善的必要条件，而脱碳层部位转移法能有效防止裂纹发生，亦是接头安全运行的重要工艺措施之一。

Interface Microstructure and its Influence of Dissimilar Ferrite Heat Resistant Steel Joint

The interface microstructure and its influence in ferritic dissimilar metal weld joints were reviewed. The results show that in the heterogeneous interface structure of ferritic DMWs joints for post-weld heat treatment and long-term service at elevated temperatures, carbon-denuded and carbon-enriched layers are usually formed. Among the influencing factors on the interface structure of ferrite DMWs joints, the chemical composition of the weld metal has an important impact; the influence of post weld heat treatment specification (temperature and time) and operation time at high service temperature is very prominent; the influence of welding process parameters can not be ignored.The formation of cracks near the interface of dissimilar steel joints and the decrease of creep strength with the increase of L-M parameters are all caused by carbon migration at the interface of dissimilar steels.The control method of weld composition is a necessary condition for the control or improvement of the joint interface structure, and the transfer method of the decarburized layer position can effectively prevent the occurrence of cracks, and is also one of the important process measures for the safe operation of the joint.