Microstructure and mechanical properties of fiber laser welded QP980 steel
Microstructure and mechanical properties of fiber laser welded QP980 steel
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光纤激光焊接QP980钢的显微组织与力学性能
DOI：
10.1016/j.jmatprotec.2018.02.015
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发表时间：
2018-06-01
影响因子：
6.3
通讯作者：
Peng, Yun
中科院分区：
文献类型：
--
作者：
Guo, Wei;Wan, Zhandong;Peng, Yun
QP980激光焊接熔合区为全马氏体组织，具有较高的硬度(493Hv)。亚临界热影响区含有部分回火马氏体，硬度下降21Hv。在动态应变率下，接头和母材表现出正应变率相关的抗拉强度、屈服强度和能量吸收，而延伸率响应因热软化效应而不同。所有接头均在母材处失效，表现为典型的延性断裂。接头疲劳极限低于母材疲劳极限(分别为171 Mpa和261 Mpa)。接头疲劳试件由于对应力集中的敏感性高于母材，在焊缝区失效。疲劳裂纹起源于试件表面，并与二次裂纹一起沿疲劳条纹扩展。
The fusion zone of laser welded QP980 composed of fully martensitic structure exhibited high hardness (493 Hv). The sub-critical heat affected zone contained partially tempered martensite with a hardness drop (21 Hv). The joints and base metal showed positive strain rate dependent tensile strength, yield strength and energy absorption in dynamic strain rate regime, while elongation responded differently because of thermal softening effect. All the joints failed at base metal showing a typical ductile fracture. Fatigue limit of the joints was lower than that of base metal (171 MPa and 261 MPa, respectively). Fatigue specimens of Joints failed at weld area because of their higher sensitivity to stress concentration than base metal. Fatigue crack originated from the specimen surface, and propagated through fatigue striations together with secondary cracks.