采用Cu-xTi合金焊材的紫铜厚大结构件He-TIG焊缝组织及性能研究

Microstructure and mechanical performance of the welds by He-TIG welding of copper using Cu-xTi welding alloys

通过在焊材中添加合金元素Ti可以有效抑制紫铜厚大结构件焊接时热裂纹的问题,焊材中的钛与溶入熔池的氧反应生成TiO2上浮至熔池表面,凝固形成焊渣,从而避免裂纹源的产生。针对紫铜厚大结构件He-TIG焊自行研发了Cu-xTi合金焊材。焊材中Ti含量对紫铜焊接热裂倾向的影响明显,Ti含量应控制在2%左右。当Ti含量达到4%时,由于焊缝中形成了(β-TiCu4+TiCu)2的低熔共晶液膜从而增加了焊缝金属的热裂倾向。力学性能试验表明,采用Cu-xTi合金焊材可以获得良好力学性能的焊缝金属和接头,通过Ti元素的添加,在不降低焊缝金属及接头冲击韧性和塑性的情况下,可以大大提高强度和硬度。

.The hot cracking in copper welding is eliminated by adding element Ti in the welding materials. It has been found that element Ti melt in welding pool combines with oxygen to generate TiO2 which flow up to the surface of the welding pool and form as slag on the weld bead after solidification. The new welding matetials Cu-xTi welding alloys special for copper welding are investigated and developed. The degree of addition of Ti is critical if the susceptibility to cracking is to be reduced. If the level is allowed to exceed 4wt%, more low-melting point eutectics （TiCu2＋13-TiCu4） will be formed in the weld,and cracking susceptibility will increase. Although adding Ti increases the strength and hardness of the weld compared to the copper base, the plastic properties and the impact ductility are not significantly decreased.