原位内生TiC对激光-电弧复合焊接高强钢接头组织和性能的影响.pdfVIP

第 51 卷第 12 期 机 械 工 程 学 报 Vol.51 No.12 2 0 1 5 年 6 月 JOURNAL OF MECHANICAL ENGINEERING Jun. 2 0 1 5 DOI ：10.3901/JME.2015.12.076 原位内生 TiC 对激光-电弧复合焊接高强钢接头 组织和性能的影响* 宋丙文 刘双宇 刘凤德 徐春鹰 张 宏 (长春理工大学机电工程学院 长春 130025) 摘要：以高强钢为试验材料，采用CO2 激光-熔化极活性气体保护焊(Metal active gas arc welding，MAG)复合焊接方法，研究 原位内生 TiC 对高强钢焊接接头组织和性能的影响。研究结果表明：原位内生 TiC 颗粒能够细化焊缝组织，对高强钢焊接接 头的综合性能有很大的提高，其中 wCNT ∶wTi=15% 的焊缝上部中心区主要由树枝晶组成，二次枝晶平均宽度为 8.4 μm 。焊缝 下部主要由大量的等轴晶组成。而未加粉焊缝上部中心区主要由大量柱状晶组成，柱状晶平均宽度为 13.25 μm 焊缝下部主 要由大量细小柱状晶组成。通过断口分析知，wCNT ∶wTi=15%焊缝处的断口处产生大量细小韧窝，焊接接头主要是韧性断裂， 而未加粉的焊接接头主要是脆性+韧性断裂。通过力学性能测试知，原位内生 TiC 对高强钢激光- 电弧复合焊接接头的冲击吸 收能量、弯曲能量度及硬度都有明显提高，但是对抗拉强度影响不大。 关键词：激光- 电弧复合焊接；微观组织；力学性能 中图分类号：TG456 Effect of in Situ TiC on Microstructure and Properties of the Laser-arc Hybrid Welding Joints of High Strength Steels SONG Bingwen LIU Shuangyu LIU Fengde XU Chunying ZHANG Hong (College of Mechanical Engineering, Changchun University of Science and Technology, Changchun 130025) Abstract ：A CO laser-metal active gas arc welding(MAG) hybrid welding technology is used to weld the high strength steel. The 2 effects of in situ TiC on microstructure and properties of welded joints are investigated. Results indicate that microstructure can be refined by TiC particles. The overall performance of high strength steel welded joints has been greatly improved. When the wCNT ∶ wTi=15%, the upper center part of the weld is composed mainly by dendrites. The average width of secondary dendrite is 8.4 μm. The bottom of weld is composed mainly by large numbers of small equiaxed. When the wCNT ∶wTi=0%, the upper center part of weld is mainly composed by large numbers of columnar grains. The average width of the columnar