Abstract
Currently, plasma gouging machines supplied by domestic equipment manufacturers are classified according to orifice gases used in them; some use mixtures of 30% hydrogen and argon, whereas some use only nitrogen. Stainless steel and aluminum alloy, which were previously used in arc welding, are used with a carbon steel for plasma gouging, thus resulting in high efficiency and high quality gouging. The plasma gouging process using only nitrogen allows carbon steel to be processed with a single gas, which is a potential selling point. However, plasma gouging or cutting using a mixture of gases is more expensive owing to the consumption of the two orifice gases. In order to use hydrogen, which is a combustible gas, special safety control is necessary in the storage of hydrogen gas cylinders. Compressed air can be easily used as an orifice gas; therefore, the author investigated various properties of the plasma gouging method using compressed air. In this lecture, we will report on the results of the investigation on the weldability in a groove formed by the air plasma gouging method.
