DP980与22MnB5激光拼焊接头性能

Properties of Laser Tailor-Welded Joints of DP980 and 22MnB5

通过激光焊接技术,制备了DP980和22MnB5的拼焊接头,并研究了其组织和性能。结果表明,DP980侧的焊接热影响区(HAZ)存在明显的软化现象,软化区的最低硬度约为DP980母材的75%;22MnB5侧的HAZ无软化现象,HAZ的硬度提高到了22MnB5母材的2~2.4倍。拼焊接头的拉伸断裂发生在22MnB5侧的母材中,抗拉强度为670 MPa左右。DP980侧HAZ的软化区由回火马氏体和铁素体组成,两相区由少量的淬火马氏体和铁素体组成,硬化区基本由板条马氏体组成;22MnB5侧HAZ不完全淬火区的组成跟DP980两相区的相似,完全淬火区全部为板条马氏体;焊缝区为粗大的板条马氏体。

By use of the laser-welding technique, the tailor-welded joints of DP980 and 22MnB5 are fabricated, and their microstructures and properties are researched. The results show that an obvious softening occurs in the heat-affected zone （HAZ） of DP980 and the minimum hardness of the softening zone is about 75% of that of the DP980 base material, however, there is no softening phenomenon in the HAZ of 22MnB5 where the hardness is increased to 2-2.4 times that of 22MnB5 base material. The tailor-welded joints have fractures at the 22MnB5 base material, whose tensile strength is around 670 MPa. The softening zone of the HAZ of DP980 is composed of temper martensite and ferrite, the two-phase zone is of a small amount of quenched martensite and ferrite, and the hardening zone is basically of lath martensite. The incomplete quenching zone of the HAZ of 22MnB5 has a similar composition with the two-phase zone of DP980 side, the complete quenching zone is of all lath martensite, and the weld zone is of coarse lath martensite. Key words laser technique; tailored blank laser welding; 22MnB5 hot-formed steel; DP980 dual-phase steel; microstructure; mechanical properties