Creep Rupture Behavior in Dissimilar Weldment between FB2 and 30Cr1Mo1V Heat-Resistant Steel

• Published in: International journal of photoenergy 2021-12, Vol.2021, p.1-11
• Main Authors: Xiong, Jiankun, Yang, Jianping, Zhao, Haiyan, Yang, Lin, Guo, Yang, Nie, Fuheng, Xu, Dexing, Yu, Liping, Cao, Fenghong
• Format: Article
• Language: English
• Subjects: Coalescing; Crack initiation; Creep (materials); Creep tests; Dimpling; Dislocation density; Ductile fracture; Ductility; Fracture mechanics; Fracture surfaces; Heat resistant steels; High temperature; Laves phase; Metals; Morphology; Precipitates; Rupture; Scanning electron microscopy; Steel; Stress concentration; Transgranular fracture; Weld metal; Weldments
• ISSN: 1110-662X; 1687-529X
• DOI: 10.1155/2021/1143989

Creep rupture behavior of dissimilar weldments between FB2 and 30Cr1Mo1V heat-resistant steel by multipass welding at 783 K (510°C) under different stresses (260 to 420 MPa) was researched. The fitted creep rupture exponent is 14.53, and the 10,000 h extrapolating strength values predicted by the power law and Larson-Miller parameter show good agreement with experimental data. The samples exhibit a ductile fracture character and fracture in the weld fusion zone, which has a highly heterogeneous microstructure and grains with different morphologies and sizes and an obvious softening. There exist a decrease in the dislocation and precipitate density and an increase in the subgrain size in the weld metal after creep. The rupture is a transgranular fracture characterized by dimples as a result of microvoid coalescence. Laves phases along with copper-rich precipitates are observed in the vicinity of fracture surface, which creates a stress concentration that can cause transgranular fracture initiation.