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针对DP980双相高强钢激光拼焊接头进行动态拉伸实验,对比分析不同应变速率下接头的力学性能和变形规律.结果表明:接头热影响区存在明显马氏体回火软化,接头抗拉强度与母材相当,屈服强度稍高于母材,但断后延伸率降低50%左右.在1×10~(-3)~1×10~3 s~(-1)应变速率范围,接头强度随应变速率增加而增大,断后延伸率呈先上升后下降趋势;在1×10~(-3)~1×10~1 s~(-1)应变速率范围,接头拉伸断裂位置位于热影响区外边缘;在1×10~2~1×10~3 s~(-1)高应变速率范围,断口位于软化区,接头不同分区组织性能差异是主要原因.
The dynamic tensile test of DP980 high-strength steel laser welded joints was carried out and the mechanical properties and deformation rules of joints under different strain rates were compared.The results show that there are obvious martensitic temper softening, joint tensile strength Compared with the base metal, the yield strength is slightly higher than that of the base metal, but the elongation at break is reduced by about 50% .In the strain rate range of 1 × 10 -3 ~ 1 × 10 -3 s -1, The strain rate increases and the elongation at break increases first and then descends; in the range of 1 × 10 -3 ~ 1 × 10 -1 s -1, the tensile fracture location of the joint is located in the thermal influence In the high strain rate range of 1 × 10 ~ 2 ~ 1 × 10 ~ 3 s ~ (-1), the fracture is located in the softening zone, which is the main reason for the difference in microstructure and properties of the joints.