Constitutive relationship of fusion zone in the spot welds of advance high strength steels
Constitutive relationship of fusion zone in the spot welds of advance high strength steels
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DOI：
10.1016/j.jmapro.2019.08.007
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发表时间：
2019-09
影响因子：
6.2
通讯作者：
Cheng Luo;Yansong Zhang
中科院分区：
文献类型：
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作者：
Cheng Luo;Yansong Zhang
熔合区的本构关系是研究高强度钢电阻点焊断裂行为的实用数值模型的基础。在本文中，直接测量本构关系，通过开发一个简单而有效的实验装置与新的小拉伸试样，可以在典型的通用拉伸机。采用该试样对DP590钢、Q&P980钢和22MnB5钢点焊熔合区的主要性能进行了表征。与DP 590钢和22MnB5钢熔合区1100 MPa的极限抗拉强度相比，Q & P980钢熔合区由于残余奥氏体的形成，其强度高达1700 MPa。应变分布结果表明，Q&P980钢熔合区晶粒取向差较小的非均匀组织导致其断裂应变大于其它熔合区。结果表明，Q&P980钢的熔合区具有比DP590钢和22MnB5钢更好的上级强度和塑性。
Constitutive relationship of fusion zone is essential for a practical numerical model to analyze the fracture behavior of resistance spot welded advance high strength steels. In this paper, the constitutive relationship was directly measured by developing a simple but effective experimental setup with the new small tensile specimen that could be available in typical universal tensile machines. This new specimen was used to characterize the key properties of fusion zones in the spot welds of DP590 steels, Q&P980 steels and 22MnB5 steels. Compared to the ultimate tensile strength in the fusion zone of DP590 steels and 22MnB5 steels with the value of 1100 MPa, the strength was up to 1700 MPa in the fusion zone of Q&P980 steels due to the formation of retained austenite. Strain distribution results indicate that the heterogenous microstructure with smaller grain misorientation in the fusion zone of Q&P980 steels leads to the larger fracture strain in a comparison to other fusion zones. These results revealed that the fusion zone of Q&P980 steels exhibited a superior strength and ductility compared to that of DP590 steels and 22MnB5 steels.