Welding heat input for synergistic improvement in toughness and stress corrosion resistance of X65 pipeline steel with pre-strain. (September 2022)

• Record Type: Journal Article
• Authors: Han, Yongdian; Zhong, Shifang; Tian, Lei; Fei, Jiyuan; Sun, Youhui; Zhao, Lei; Xu, Lianyong
• Is Part Of: Corrosion science. Volume 206(2022)
• Publication Date: 2022-09
• Subjects: X65 pipeline steel -- Coarse-grained heat-affected zone -- Microstructure -- Hydrogen embrittlement -- Stress corrosion -- Effects of pre-strain; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2022.110478
• Languages: English
• ISSNs: 0010-938X

Abstract

Abstract: The microstructure, hydrogen embrittlement sensitivity, fracture toughness, and influence of pre-strain on the sulfide stress corrosion cracking (SSCC) sensitivity of the coarse-grained heat-affected zone of X65 pipeline steel with large deformation were studied to determine the optimal welding heat input in an acidic H2 S environment. After pre-straining, the microstructures of the specimens changed insignificantly, but their ductility decreased. The acicular ferrite microstructure obtained under a low heat input demonstrated the synergistic improvement in the SSCC resistance and fracture toughness under pre-strain, especially at t 8/5 = 20 s. The M/A constituents interface potentially causes microcrack initiation and interconnection under pre-strain. Highlights: The microstructures of CGHAZ with different welding heat input are observed. When t8/5 = 20, 25, 30, and 60 s, the CGHAZ has excellent fracture toughness and HE sensitivity. The morphology and distribution of the microstructure do not change significantly after 5% pre-straining. The CGHAZ with a t8/5 of 20 s can synergistically improve SSCC resistance and fracture toughness with pre-strain.