国内大口径、高钢级管道焊接及焊缝检测技术现状

Current status of welding and weld testing technologies for large-diameter high-grade pipelines in China

针对国内大口径、高钢级管道普遍采用半自动焊技术而逐渐暴露的焊接质量问题,研究了大口径、高钢级管道的焊接技术及焊缝检测技术。分析了半自动焊与全自动焊对大口径、高钢级管道环焊缝质量的影响因素,并通过西气东输高钢级管道焊口泄漏事故失效分析报告、管材低温冲击试验与金相分析报告及环焊缝焊接工艺试验,验证了影响焊接质量的因素;开展了半自动焊与全自动焊经济性对比,得到了焊接机组成本与完成工作量的关系;研究了自动超声波检测技术的可靠性,提出了国内全自动焊焊缝检测的方法。由此可得:对于大口径、高钢级管道,全自动焊能够有效避免半自动焊环焊缝低温冲击功值偏低且离散的问题,具有质量可靠、工效提升的优势,但从经济性角度考虑,只有当全自动焊工作量大于经济焊接工作量时,全自动焊的经济效益才会超过半自动焊;全自动焊焊缝质量可采用自动超声波检测技术检验。因此,建议在大口径、高钢级管道的建设施工中,全面推行全自动焊技术。

In China, semi-automatic welding technology is commonly used at large-diameter high-grade pipelines, and the issues related to its welding quality emerge gradually. To solve these problems, the welding technologies and the weld testing technology for large-diameter high-grade pipelines were explored. First, the effects of semi-automatic welding and automatic welding on the girth weld quality of large-diameter high-grade pipelines were investigated. And the factors affecting the welding quality were verified based on the failure analysis report of high-grade pipeline joint leakage in West- to-East Gas Pipeline Project, the low-temperature impact test ＆ metallographic examination report of tabular goods and the girth welding test. Second, semi-automatic welding and automatic welding were economically compared, and the relationship between the cost and the fulfilled work load of welding outfit was clarified. Third, the reliability of automatic ultrasonic testing technology was studied and the automatic weld testing method suitable for domestic conditions was proposed. It is indicated that as for large-diameter high-grade pipelines, automatic welding can avoid effectively the low and discrete low-temperature impact energy of semi-automatic girth weld, and it is advantageous with reliable quality and efficiency improvement. However, the automatic welding is economically superior to the semi-automatic welding so long as its work load is higher than the economic value. The weld quality of automatic welding can be inspected by the automatic ultrasonic testing technology. To sum up, it is recommended to implement fully the automatic welding technology in the construction of large-diameter high-grade pipelines. （2 Figures, 1 Table, 21 References）