轴向压力对异种钢水下摩擦锥塞焊接头组织及力学性能的影响

Effects of axial force on microstructures and mechanical properties of underwater friction taper plug welding for dissimilar steel

在X52管线钢上采用Q345塞棒进行水下摩擦锥塞焊工艺试验研究,讨论轴向压力对塞焊接头组织和力学性能的影响.结果表明,对给定7 000 r/min焊接转速在30 kN轴向压力下,塞焊缝底部圆角过渡处易产生未结合缺陷,随着轴向压力增加达到35 kN以上,可以获得完全结合的致密塞焊缝,焊缝顶锻区及底部圆角过渡处的热影响区也不断扩大.由于水介质快速冷却作用,焊缝区组织特征比较复杂,主要由板条状马氏体和板条状贝氏体组成,硬度分布不均匀并产生明显淬硬现象其硬度可达450 HV1.在0℃下焊缝中心冲击吸收能量也会随着轴向压力的增加而不断提高,最高可以达到62 J,但远低于母材的267 J.

In this study,friction taper plug welding(FTPW)experiments were performed using X52 pipeline steel as base material and Q345 steel as plug.The effects of axial force on microstructures and mechanical properties for FTPW weld were discussed.The results showed that lack of bonding defect formed in the weld at the bottom corner under the conditions of 7 000 r/min rotating speed and 30 kN axial force.With the axial force increasing to 35 kN,the weld defect was avoided,and the width of forged zone and HAZ at the corner near bottom hole expanded.Due to the effect of quick water cooling,the microstructure of the FTPW weld was complex,which consisted of lath martensite and lath bainite.The hardening tendency of FTPW weld was obvious,and the hardness value reached 450 HV1.The V-notch impact absorbed energy at 0°C in the center of the weld continuously increased as the axial force increase,which reached up to 62 J and was much lower than that of the base material(267 J).