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研究发现,焊缝是由粗晶、细晶等不同尺寸的晶粒组成,组织形貌为回火马氏体,这将会导致焊缝的性能发生波动,其硬度试验表明焊缝中存在不同程度的由于焊缝组织结构引起的波动。高温持久试验后再次进行硬度分析,发现经过高温持久试验后焊缝区硬度比试验前硬度略低,同时热影响区、母材等硬度也存在降低的现象。经分析发现,这与母材及焊缝中析出的碳化物相关,特别是晶界处碳化物的大量析出、聚集导致了接头性能的降低。本文的研究结果可为窄间隙热丝TIG焊过程参数控制及探讨高温服役过程中的失效行为提供依据。利用窄间隙热丝TIG焊对X10CrMoVNb9-1钢汽轮机阀门进汽接管进行多层全位置焊接,对焊接接头各微区组织与性能的相关性展开研究。
The study found that the weld is composed of grains of different sizes, such as coarse grains and fine grains. The morphology of the weld is tempered martensite, which will cause fluctuations in the performance of the weld. The hardness test shows that there are differences in the weld The degree of fluctuation due to the microstructure of the weld. After long-term high-temperature test hardness analysis again and found that after the endurance test after the hardness of the weld zone hardness slightly lower than before the test, while the heat-affected zone, the base material and other hardness also decreased phenomenon. The analysis shows that this is related to the precipitation of carbides in the base metal and the weld, especially the precipitation of a large amount of carbides at the grain boundaries, leading to a decrease in joint performance. The results of this paper can provide the basis for parameter control of narrow gap hot wire TIG welding process and the failure behavior during high temperature service. The use of narrow gap hot wire TIG welding of X10CrMoVNb9-1 steel steam turbine inlet manifold multi-level all-position welding, weld micro-zone organization and performance of the correlation study.