A Comparative Analysis on Microstructure and Fracture Mechanism of X100 Pipeline Steel CGHAZ Between Laser Welding and Arc Welding
A Comparative Analysis on Microstructure and Fracture Mechanism of X100 Pipeline Steel CGHAZ Between Laser Welding and Arc Welding
复制标题
X100管线钢CGHAZ激光焊与电弧焊显微组织及断裂机理对比分析
DOI：
10.1007/s11665-019-04412-5
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发表时间：
2019-11-04
影响因子：
2.3
通讯作者：
Liu, Zhenguang
中科院分区：
文献类型：
--
作者：
Qi, Xiaonan;Di, Hongshuang;Liu, Zhenguang
本研究的目的是比较和对比X100管线钢激光焊接和埋弧焊焊接热影响区组织和断裂机制的差异。在MMS-200型热模拟试验机上，采用自制夹具进行了激光焊和埋弧焊的单道焊热模拟试验。结果表明，激光焊接CGHAZ和埋弧焊CGHAZ的组织分别为板条马氏体和粒状贝氏体。激光焊接CGHAZ的冲击能为27J，断裂模式为延性断裂；埋弧焊CGHAZ的冲击能为7.7J，断裂模式为脆性断裂。建立了不同焊接方式下裂纹的形核和扩展机理。激光焊接CGHAZ过程中，微裂纹在位错聚集位置形核，残余奥氏体形核抑制裂纹形核。埋弧焊CGHAZ的形核位置在M-A组分。激光焊接CGHAZ的主要裂纹是由一个或少量微裂纹形成的。埋弧焊CGHAZ的主要裂纹是由大量微裂纹形成的。裂纹形核和扩展机制的不同是激光焊接CGHAZ的冲击能高于埋弧焊CGHAZ的原因。
The objective of this study is to compare and contrast the differences in microstructure and fracture mechanism between CGHAZ of laser welding and submerged arc welding in X100 pipeline steel. The single-pass welding thermal simulation test of laser welding and submerged arc welding was carried out in MMS-200 thermal simulation test machine using self-made fixtures. The results indicated that the microstructure of laser welding CGHAZ and submerged arc welding CGHAZ was lath martensite and granular bainite, respectively. The impact energy of laser welding CGHAZ was 27 J, and the fracture mode was ductile fracture; the impact energy of submerged arc welding CGHAZ was 7.7 J, and the fracture mode was brittle fracture. The nucleation and propagation mechanism of cracks in different welding modes was established. Microcracks nucleated at the position of dislocation accumulation and remained austenite suppressed crack nucleation in laser welding CGHAZ. The nucleation site was at the M–A constituents in submerged arc welding CGHAZ. The main crack of laser welding CGHAZ was formed by one or a small number of microcracks. The main crack in submerged arc welding CGHAZ was formed by a large number of microcracks. The difference between crack nucleation and propagation mechanism is the reason why the impact energy of laser welding CGHAZ is higher than of submerged arc welding CGHAZ.