EFFECT OF HEAT TREATMENT ON THE SUSCEPTIBILITY OF ENVIRONMENTAL CRACKING FOR SPV50Q STEEL WELDMENT
SPV50Q steel is often used to fabricate spherical tanks for holding liquefied petroleum gas (LPG) and those tanks are designed to free post weld heat treatment (PWHT) for avoiding the possible reduction in strength. However, the welded parts, especially the heat-affected zone, are found to be susceptible to sulfide stress corrosion cracking (SSCC) in LPG environment contaminated accidentally by wet H2S. The failure analysis showed, besides the presence of wet H2S, the existence of welding residual stress in weldment plays a major role in the occurrence of SSCC. Therefore, in order to explore the effect of PWHT on SSCC susceptibility of SPV50Q steel weldment, some experiments were performed for the crosswelded specimens which are heat treated at 590 ℃ for one or multiple times. The susceptibility to environmental cracking were evaluated by slow strain rate testing (SSRT) in H2S-containing solution. The feature of fracture and the morphologies of cracks were observed by scanning electrode microscope and optical microscope. The results indicate that the susceptibility of environmental cracking for the specimens with heat treatment is decreased as compared with specimens without heat treatment, which can provides technology support for the remanufacturing of the LPG spherical tanks having suffered from SSCC.
Jian-Qun Tang Jian-Ming Gong Jie Tang Yong Jiang
School of Mechanical and Power Engineering, Nanjing University of Technology, Nanjing 210009, China
国际会议
第九届工程结构完整性国际会议(The Ninth International Conference on Engineering Structural Integrity Assessment)
北京
英文
2007-10-15（万方平台首次上网日期，不代表论文的发表时间）