某火电厂超超临界机组锅炉用T91钢蒸汽采样管焊接接头在使用约4200 h后出现了开裂，通过宏观检验、显微组织分析、拉伸试验、拉伸断口分析以及硬度检测等对开裂的原因进行了分析。结果表明：在焊接接头靠近母材的热影响区中，马氏体组织出现典型的索氏体化，粗大的析出相(Laves相和M23 C6相)在晶界上呈链状分布，导致该区域的强度和硬度降低，并引起晶界弱化，在高温和多向应力的共同作用下该区发生开裂。
Crack was found on welded joint of a T91 steel steam sampling tube in power plant ultra-supercritical unit boiler after using about 4 200 h.The cracking causes were analyzed through macroscopic inspection,microstructure analysis,tensile test,fracture analysis and micro-hardness testing.The results show that the martensitic structure of the heat affected zone near base metal was obviously decomposed into sorbite,and the coarse Laves phase and M23 C6 phase distributed on the grain boundaries continuously.These changes in microstructure not only resulted in the decrease of strength and hardness of the area,but also brought about grain boundary weakening.Under the combined action of high temperature and multiaxial stress,the welded joint eventually generated type IV crack failure.
参考文献
| [1] | 杨富;李为民;任永宁.超临界、超超临界锅炉用钢[J].电力设备,2004(10):41-46. |
| [2] | 史轩.超超临界电站锅炉关键材料的新进展[J].机械工程材料,2009(9):1-5. |
| [3] | 王学;潘乾刚;陶永顺;章应霖;曾会强;刘洪.P92钢焊接接头Ⅳ型蠕变断裂特性[J].金属学报,2012(4):427-434. |
| [4] | Ladislav Falat;Milan Suoboda;Anna Vyrostkova.Microstructure and creep characteristics of dissimilar T91/TP316H martensitic/austenitic welded joint with Ni-based weld metal[J].Materials Characterization,2012:15-23. |
| [5] | 范长信;张红军;周荣灿;董雷.超超临界机组锅炉用新型耐热钢的焊接[J].电力设备,2006(4):11-14. |
| [6] | 柯浩;张晓昱;欧阳杰;孙涛;徐雪霞;阎光宗.长时运行后高温再热器T91钢管的冲击韧性[J].机械工程材料,2013(9):45-48. |
| [7] | 崔正强;王延峰;赵双群;李强.T91钢管在600℃长期时效后的组织及力学性能[J].机械工程材料,2014(12):78-81. |
| [8] | 胡新芳;岳增武;傅敏;于光强;王金海;刘国刚.高温再热器T91钢焊接接头裂纹分析[J].热力发电,2009(2):74-77. |
| [9] | 章应霖;王学;张建强.P91钢焊接接头性能及其存在问题的讨论（续）[J].水利电力机械,2001(2):23-25. |
| [10] | 王宝才;王志伟;焦荣格.P91钢焊接工艺研究[J].河北电力技术,2006(4):20-22. |
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