TWIP_IF激光拼焊板的组织性能与成形性研究.pdf

TWIP/IF 激光拼焊板的组织性能与成形性研究 1 米振莉，杨 林，江海涛，李 辉，唐 荻 （北京科技大学冶金工程研究院，北京市 100083 ） 摘要：本文对 1.5mm 厚 Fe-Mn-C 系 TWIP 钢和 1.2mm 厚 IF 钢进行了激光拼焊实验，用光学显微镜观察了焊接接 头微观组织，EDX 分析了碳和锰元素的分布，区分出焊缝区、热影响区和母材的成分与微观相的不同，测试了其 维氏硬度的分布曲线，对拼焊板进行了拉伸和埃里克森杯突试验。实验结果表明，焊缝区的成分和组织与 TWIP 钢和 IF 钢母材都不同；拉伸试验均断裂在 IF 钢一侧，TWIP 钢母材及焊缝基本上未发生变形；焊缝的高硬度和 组织不均匀性，造成了拼焊板的成形性低于 TWIP 钢和 IF 钢母材。 关键词：金属材料；拼焊；微观组织；成形性 Investigation on Microstructure ，Mechanical Properties and Formability of Laser-welded Joints of TWIP and IF Steels MI Zhenli, YANG Lin, JIANG Haitao, LI Hui, TANG Di （Engineering Research Institute，University of Science and Technology Beijing ， Beijing, 100083, China ） Abstract: Tailor welded blanks （TWB ）are essential to meet the demands of safety and fuel efficiency in vehicles. Whether TWBs are used or not ，attaching panels made of different materials such as IF and TWIP remains a challenge. In this paper, the results of laser welding of Fe-Mn-C series TWIP steel and IF steel were presented. A 1.5kw HS-40 CO2 laser beam was used to join 1.5mm thickness TWIP with 1.2mm thickness IF steel. The microstructures were characterized by means of optical metallorgraphy to differentiate the fusion zone (FZ)，heat affected zone (HAZ) ，and the base metal ；microhardness ，tensile and erichsen tests were performed to evaluate the mechanical properties of the joints. The results indicate that the composition and microstructure of fusion zone are different from TWIP and IF base metal which are not suitable for the formability of the steels; the HAZ zone in IF steel is greater than in the TWIP steel; fracture all occurred in the IF