GHTA Starting Experiments Using DC High Voltage Process in the ISS Orbital Pressure

Abstract

As a feasible welding method in space, the authors have proposed the Space GHTA (Gas Hollow Tungsten Arc) welding method in the previous papers. The Space GHTA welding using the high frequency power source may have an electro-magnetic noise problems of computer equipments placed on the ISS. In this report, the Space GHTA welding experiment using the DC high voltage power source was carried out in the ISS orbital pressure 10^—5 Pa.
The results are summarized as follows,
1) It is made clear that there is a shifting phenomenon in which a glow or an arc is formed after the spark at starting phenomenon of the Space GHTA welding in high vacuum condition, and the feature of those starting phenomenon are demonstrated.
2) The arc ignition unit of GHTA by DC high voltage power source can be used in the ISS orbital pressure.
3) The arc formation ratio increases with increasing the stating voltage, but the starting current has no effect on the arc formation ratio.
4) The arc formation ratio increases in order of arc operating gas Ne, Ar and Kr under the same starting conditions.