Measurement of Arc Temperature during Automatic Welding Torch Control by Multi-point High-speed Spectroscopy

TIG arc welding is often used because this welding has high quality and strength. However, when the distance between electrodes is changed, the arc length and arc voltage are displaced, and the heat transfer rises or falls, causing welding defects. Therefore, it is necessary to adjust and control the distance between the electrodes automatically, because the number of special artisan is quite limited. In this research, the arc temperature displacement with respect to the displacement of the interelectrode distance was calculated by driving the welding torch vertically, automatically controlling the interelectrode distance, and measuring the arc temperature during the control. Specifically, the welding torch was controlled up and down by a microcomputer, and the arc voltage was measured. At the same time, the temperature was calculated from the spectra using the multi-point high-speed spectroscopy of the arc near the base metal and the gas vapor generated when the base metal melted down. As a result, it was possible to measure the arc temperature when welding defects occurred because of the displacement of the distance between electrodes.