Development of the Space Gas Hollow Tungsten Arc Welding Process for the Space Development of the World

1993年，我们提出了一种独特的、安全的空间GHTA(气体空心钨极弧)焊接技术，可以在真空中进行。我们对该技术在空间上的应用进行了研究和开发。建立了在空间环境压力10^~(-5)~(-5)帕下安全启动弧光放电的技术和真空去除铝合金熔池氧化膜的技术。为空间GHTA焊接在本研究中的应用奠定了基础。直流高压引弧法和接触式引弧法的引弧现象由于电磁噪声的影响，高频引弧法在焊接引弧时可能会对放置在空间站上的电子设备造成阻碍。为此，我们在国际空间站在轨运行的Pre-…空间GHTA焊机上进行了直流高压引弧法和接触引弧法焊接铝合金的启动试验更有把握。结果表明，采用这些引弧方法可以实现铝合金焊接的引弧，并阐明了真空引弧的特点。直流高压和接触引弧方法中焊接参数对引弧现象的影响研究了这些引弧方法中的焊接参数对引弧现象的影响。证实了触摸启动方式在性能、重量、安全性等方面均优于直流高压启动方式。铝合金熔池氧化膜的焊接现象及去除机理研究发现，采用逆变式脉冲直流GHTA焊机可以在真空中去除铝合金熔池上的氧化膜。通过高速摄像机的观察，阐明了氧化膜的去除机理。我们还证明了铝合金在去除氧化膜的情况下，采用填充焊丝焊接的对接接头具有足够的强度。较少

In 1993, we proposed a unique and safe space GHTA (Gas Hollow Tungsten Arc) welding technology which can be performed in a vacuum. We carry out the research and development for the space applications of this technology. We established the technologies which safely surely start the arc discharge at space environmental pressure 10^<-5> Pa and technology which removes the oxide film on the molten pool of aluminum alloy in a vacuum. As a result, we were able to establish the basic technology for applying the space GHTA welding in this research.1. Phenomena of arc start by DC high-voltage starting method and touch starting methodThe high-frequency starting method which was employed for the arc star of welding may be obstacle for electric devices placed on the ISS due to electromagnetic noise. Therefore, we conducted the start experiments of welding on an aluminum alloy by the DC high-voltage starting method and touch starting method with the space GHTA welding machine at the ISS orbital pre … More ssure. The arc starts of welding on aluminum alloy were shown to be possible by use of these starting methods, and the characteristics of these arc starts in a vacuum were clarified.2. Effects of welding parameters in DC high-voltage and touch starting methods on arc starting phenomenaWe investigated the effects of the welding parameters in these starting methods on the starting phenomena. We confirmed that the touch starting method excels the DC high-voltage starting method in performance, weight, safety.3. Welding phenomena and removal mechanism of oxide films on molten pool in aluminum alloyWe discovered that the oxide films on molten pool in aluminum alloy could be removed by using the inverter-controlled pulsed DC GHTA welding machine in a vacuum. The removal mechanism of oxide films was clarified by the observation with high-speed video camera. We also demonstrated that the butt welding joints on aluminum alloy welded by supplying a filler wire under removing the oxide film, having the enough strength. Less