利用连续光纤激光器进行了800 MPa级和1000 MPa级双相钢的激光拼焊试验,研究了马氏体含量对双相钢焊接接头组织和性能的影响。结果表明,不同马氏体含量双相钢的焊接接头均由全马氏体区和不完全相变区组成。两种焊接接头不完全相变区的宽度和显微硬度的降幅较小,其拉伸断裂位置均位于母材。1000 MPa级双相钢焊接接头在杯突试验中沿不完全相变区直接开裂并扩展,杯突值达到母材的85.0%;800 MPa级双相钢焊接接头则垂直于全马氏体区方向开裂,杯突值达到母材的91.7%,成形性能好。

A continuous fiber laser is used for the tailored blank laser welding of 800 MPa and 1000 MPa dual-phase (DP) steels and the effects of martensite content on the microstructure and properties of laser welded DP steel joints are investigated. The results show that the laser welded DP steel joints with different martensite contents are all composed of the full-martensite area and the non-full-phase-transformation area. The widths and microhardness of two laser welded joints are relatively reduced, and their tensile fracture positions are both in the base materials (BMs). The 1000 MPa welded DP steel joint directly cracks and expands along the non-full transformation area during the erichson test and its erichson value is 85.0% that of the BM. In contrast, the 800 MPa welded DP steel joint cracks perpendicular to the full-martensite area and its erichson value is up to 91.7% that of the BM.