送丝速度对铝/钢激光填丝熔钎焊性能的影响

采用光纤激光器对铝/钢异种金属搭接接头进行激光填丝熔钎焊试验研究。分析了送丝速度对焊缝成形质量、金属间化合物层厚度及力学性能的影响。试验结果表明,选择适当的送丝速度,利用铝和钢的不同熔点,使铝母材刚好熔化但是钢母材不熔化,熔化的铝母材与填充金属一起铺展在钢母材表面并与其实现钎焊连接,可形成优质的熔钎焊接头。当送丝速度小于3. 5 m/min时,易形成硬脆性金属间化合物而导致焊缝开裂。金属间化合物层厚度应控制在一定范围内,方可保证接头性能。当送丝速度为4. 5 m/min时,焊接接头强度有所提高,其线载荷达到203. 5 N/mm,约为铝合金母材抗拉强度的83. 7%。

Influence of wire feeding speed on properties of laser weld-brazed joints of aluminum/steel

Experimental study on weld-brazing of aluminum/steel dissimilar metal by fiber laser was carried out. The influences of wire feeding velocity on weld performance, intermetallic compounds thickness and mechanical properties were studied. The test results showed that high quality weld-brazed joints could be obtained by choosing the appropriate filler velocity. By using different melting points of aluminum and steel, the aluminum was just melted but the steel was not melted. The melted aluminum and the filler metal spread on the surface of steel, brazed weld was achieved. When the wire feeding velocity is less than 3.5 m/min, it is easy to form hard and brittle intermetallic compounds and lead to weld cracking. The thickness of the intermetallic compounds should be controlled within a certain range to ensure joint quality. When the wire feeding velocity is 4.5 m/min, the strength of the joint is improved, and the linear load can reach 203.5 N/mm, which is about 83.7% of that of aluminum alloy.