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对钢结构而言,诸如海洋平台、船舶、桥梁、建筑和油气管线等,焊接后的性能直接决定了其服役寿命和安全性,重要性不言而喻.在针对焊接相关问题的研究中,焊接热影响区的韧性提升一直是重点和难点.焊接热影响区会经历高达1400℃的高温,从而形成粗大的奥氏体晶粒,如果焊接参数控制不当,不能通过后续冷却过程中的相变细化组织,就会造成韧性的降低.而多道次焊接的情况更为复杂,前一道次形成的粗晶区还会在后续焊接过程中经历二次热循环,从而形成链状M-A,造成韧性的急剧下降.本文旨在对一些现有焊接热影响区的相关研究结果进行总结,探讨母材的成分、第二相及焊接工艺等因素对热影响区微观组织和性能的影响,为低温环境服役的大型钢结构的焊接性能改善提供一些设计思路.
For steel structures, such as offshore platforms, ships, bridges, buildings and oil and gas pipelines, the performance after welding directly determines the service life and safety of its importance, it goes without saying that in the study of welding-related issues, The toughness improvement of HAZ has always been the key and difficult issue.The HAZ will experience high temperature up to 1400 ℃ to form coarse austenite grain, and if the welding parameters are not properly controlled, it can not pass the phase change in the subsequent cooling process Refine the organization, will result in the reduction of toughness, while the multi-pass welding is more complicated, the former formed a coarse grain region will be in the subsequent welding process through the second heat cycle, resulting in chain MA, resulting in Toughness of the sharp decline.This paper aims to summarize some of the existing research results of the welded heat affected zone to explore the composition of the base metal, the second phase and welding process and other factors on the microstructure and properties of the heat affected zone for low temperature Environmental service of large-scale steel structure to improve the welding performance to provide some design ideas.