塞棒材料和尺寸对摩擦叠焊接头成形缺陷的影响

Eeffect of plug material and geometry on the defect of friction stitch welded joint

采用天津大学自主研制的水下摩擦塞焊设备,通过改变塞棒材料和塞孔塞棒形状尺寸,研究其对DH36钢水下摩擦叠焊接头成形缺陷的影响。结果表明,端部接触面积与塞孔塞棒间隙较小的A类塞孔塞棒形状尺寸,采用DH36,5A02 (LF2),Q235,Q345作为塞棒材料,均无法获得无缺陷的摩擦叠焊接头质量。塞棒的端部与塞孔的底部完全贴合的塞孔塞棒设计尺寸虽可在焊接初始阶段直接在容易出现缺陷的底部拐角处产热,但塞孔与塞棒之间间隙很小,焊接时间短,摩擦叠焊接头质量未得到提高。建议增大塞孔底部接触面积和塞孔塞棒之间的空间。

The effect of plug material and geometry on the defect of friction stitch welded joint of DH36 was investigated using the underwater friction taper plug welding system developed by Tianjin University. Experimental results showed that no matter DH36, 5 A02, Q235 and Q345 was employed as plug material, qualified welds could not be obtained using the plug and hole combination with undersize contact area and narrow gap between the plug and hole. The joint designed, with the tight fitting of the tip of plug and the bottom of the hole, was beneficial to heat the corner of friction taper plug welds, where the defect usually occured, at the start phase of welding but did little contribution to the weld quality due to the short welding time and the narrow gap between the plug and hole. The contact area and gap between the plug and hole were suggested to be enlarged to improve the weld quality. A qualified friction stitch welded DH36 joint could be obtained by using 5 A02, which had a good weldability and a low hardenability, as plug material and by using an optimized plug and hole combination in geometry.