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激光热丝焊热输入小,填丝效率高,焊缝熔合比小,特别适合于表面堆焊及厚板的窄间隙焊接,如何获得稳定的焊丝过渡是其关键问题。采用高速摄像观察了不同工艺参数下的焊丝过渡行为,将其分为滴状过渡、熔断过渡、连续过渡、顶丝过渡4种类型,连续过渡是稳定的焊丝过渡,是获得良好焊缝成形的前提。不同焊丝过渡行为的区别表现为焊丝熔化位置不同,这是由焊丝获得热量的大小不同所导致的。获得稳定焊丝过渡的工艺控制原则是:电阻热小于焊丝熔化热,且电阻热与熔池传热之和大于焊丝熔化热。通过理论推导对熔池外焊丝温度进行了计算,发现当电阻热将熔池外焊丝加热至接近熔点时,有利于获得稳定的焊丝过渡。
Laser heat wire welding heat input is small, wire filling efficiency, weld fusion ratio is small, especially for surface welding and thick plate narrow gap welding, how to obtain a stable wire transition is the key issue. The high-speed camera was used to observe the transition behavior of wire under different process parameters. It was divided into four types of droplet transition, fusing transition, continuous transition and top wire transition. The continuous transition was a steady wire transition, premise. The difference between the transition behavior of different wire performance for the wire melting position is different, which is caused by the wire size difference caused by the heat. The process control principle for obtaining a stable wire transition is that the resistance heat is less than the heat of fusion of the wire, and the sum of the heat of resistance and the heat transfer of the puddle is greater than the heat of fusion of the wire. By theoretical derivation, the temperature of welding wire outside the weld pool was calculated. It was found that when the resistance heat heated the welding wire outside the melting pool to near the melting point, it was in favor of obtaining stable welding wire transition.