EP/EN模数对铝合金VP-CMT焊熔滴过渡及焊道成形的影响

Effect of EP/EN Balance on droplet transfer and weld formation of Al alloy by VP-CMT

利用变极性冷金属过渡技术对铝合金进行平板堆焊,改变参数EP/EN Balance以调整正/负极性的比例。通过高速摄像及电信号采集系统对熔滴过渡过程和焊接过程电信号进行采集分析。通过金相分析,研究EP/EN Balance对焊道成形的影响。结果表明:变极性冷金属过渡堆焊过程中,正极阶段的热输入明显高于负极阶段,从而实现了"冷"和"热"的交替;通过调节EP/EN Balance参数,可以改变正/负极的比例,从而对焊接热输入进行调控;利用变极性冷金属过渡技术对铝合金进行堆焊,焊道外观成性良好;随着EP/EN Balance增加,熔深和接触角增大,余高降低。

Al alloy was deposited by using variable polarity cold metal transfer technique. The welding parameter of EP/EN Balance was varied to control the ratio of positive numbers to negative numbers in a weld cycle. During welding process,a high speed camera and an electrical signal acquisition system were used for observing the dynamic droplet transfer behavior and obtaining the electrical signals,respectively.The effect of EP/EN Balance on the formation of the welded joint was analyzed by the metallographic pictures. The results show that the heat input in positive period was higher than that in negative period. The alternation of"cold"and"heat"was realized during the variable polarity cold metal transfer welding process. The numbers of positive and negative periods were adjusted by altering EP/EN Balance,which could dominate the heat input to the welded joints. The weld bead with good appearance can be fabricated using variable polarity cold metal transfer technique. Weld depth and contact angle increased and reinforcement decreased with the increase in EP/EN Balance.