Effect of heat input on M-A constituent and toughness of coarse grain heat-affected zone in a X100 pipeline steel
Effect of heat input on M-A constituent and toughness of coarse grain heat-affected zone in a X100 pipeline steel
复制标题
热输入对X100管线钢粗晶热影响区M-A成分及韧性的影响
DOI：
10.1007/s11665-019-03941-3
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发表时间：
2019
影响因子：
2.3
通讯作者：
Chang-Jun Chen
中科院分区：
文献类型：
--
作者：
Xiao-Nan Wang;Yan-Jun Zhao;Peng-Fei Guo;Xiao-Nan Qi;Hong-Shuang Di;Min Zhang;Chang-Jun Chen
对不同马氏体含量的DP590、DP780和DP980三种双相钢板进行了激光焊接。采用光学显微镜和扫描电镜观察了激光焊接接头的显微组织，并用显微硬度计测量了焊接接头的硬度。采用拉力试验机和Erichsen试验机分别测量焊接接头的拉伸性能和成形性能。微观组织模型表明，三种不同材料的焊接接头均存在由熔合区、粗晶热影响区和细晶热影响区组成的硬化区（HZ）。其显微组织以马氏体为主，焊接接头的平均马氏体含量提高了1.9 ~ 9.8%，显微硬度是母材（BM）的1.2 ~ 1.9倍。随着BM中马氏体含量的降低，焊接接头的伸长率也随之降低，其中DP590焊接接头的伸长率较其他两种焊接接头的影响更为严重（21.8%）。在Erichsen试验中，不同马氏体含量的焊接接头的变形破坏是不同的，这是由HZ和软化区决定的。DP980焊接接头断裂发生在软化区，沿软化区平行，其余两个焊接接头断裂发生在HZ区，沿软化区垂直。DP590、DP780和DP980焊接接头的Erichsen值分别为BM的81.1、91.7和85.0%。
Laser welding was applied to three types of dual-phase (DP) steel sheets (DP590, DP780, and DP980) with different martensite contents. The microstructure of laser welded joints was observed by optical microscope and scanning electron microscope, and the hardness of welded joints was measured by a microhardness tester. The tensile testing machine and the Erichsen test machine were employed to measure the tensile properties and forming properties of welded joints, respectively. The microstructure model showed that the welded joints of three different materials all contained a hardened zone (HZ) that was composed of a fusion zone, a coarse-grained heat-affected zone, and fine-grained heat-affected zone. The microstructure of the HZ contained mainly martensite such that the average martensite content of welded joints was increased by 1.9-9.8%, and the microhardness of the HZ was 1.2-1.9 times that of the base metal (BM). Moreover, the elongation of welded joints decreased with decreasing martensite content in the BM, and the effect was severe for the DP590 welded joint (21.8%) compared to the other two welded joints. During the Erichsen test, deformation failure varied among the welded joints with different martensite contents, and it was determined by the HZ and softened zone. The fracture occurred in the softened zone and ran parallel along the zone for DP980 welded joints, whereas the fracture occurred in the HZ and ran perpendicular to this zone for the other two welded joints. The Erichsen values of the DP590, DP780, and DP980 welded joints were 81.1, 91.7, and 85.0% of the BM, respectively.