22MnB5/DP980激光拼焊板热成形淬火组织与性能

    Microstructure and Properties of 22MnB5/DP980 Laser Tailored Blank after Hot Stamping

    • 摘要: 对1.6 mm厚的22MnB5热成形钢板和DP980双相钢板进行激光拼焊后,开展了拼焊板热成形淬火实验,研究了拼焊板淬火前后的组织与性能。结果表明:焊接接头淬火前不同区域的组织在淬火后均转化为板条马氏体。拼焊接头淬火后的平均抗拉强度为1294 MPa,比淬火前提高了97%;强塑积比淬火后的整体22MnB5热成形钢板提高了23%。淬火前拼焊接头硬度呈“几”字形分布,硬度峰值位于焊接区,22MnB5母材区硬度值最低,22MnB5侧热影响区存在硬化区,DP980侧热影响区有软化区。拼焊接头淬火后,22MnB5侧的硬化区和DP980侧的软化区消失,整体硬度分布趋于平缓,硬度值由22MnB5母材区向DP980母材区先升高后降低;拼焊接头的平均硬度比淬火前提高了60%,22MnB5母材区硬度比淬火前提高了330%。

       

      Abstract: The 1.6mm thick 22MnB5 hot-formed steel sheet and DP980 dual-phase steel sheet were laser tailor-welded,and then the hot-forming quenching test of the tailor-welded plate was conducted. The microstructure and properties of the tailor-welded plate before and after quenching were studied. The results show that the microstructures of different areas of the welded joint before quenching are transformed into lath martensite after quenching; the average tensile strength of the welded joint after quenching is 1294 MPa, which is 97% higher than that before quenching; in addition, compared with that of the 22MnB5 whole hot-formed steel plate after quenching, its strength plasticity product is increased by 23%. The hardness of the welded joint before quenching is distributed in the shape of " 几 ". The peak value of the hardness distribution is located in the weld zone. The heat affected zone at 22MnB5 side has hardened zone, the heat affected zone at DP980 side has softened zone. After quenching, the hardness distribution of the welded joint tends to be flat, and the hardness firstly increases then decreases from the 22MnB5 base material area to the DP980 base material area. The tempering softening area on the DP980 side and the hardening area on the 22MnB5 side disappear. The average hardness of the welded joint is 60% higher than that before quenching. The hardness of the 22MnB5 base metal zone is 330% higher than that before quenching.

       

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