Temperature measurement of asymmetrical pulsed TIG arc plasma by multidirectional monochromatic imaging method

Abstract

Arc plasma diagnostics by spectroscopy have been often used to measure the arc properties, such as the temperature. Measurements of an axially asymmetrical arc plasma require the optical computed tomography technique. This study constructed the simultaneous and multidirectional measurement system by six sets of CCD camera and interference filter with monochromatic imaging method. The deviation of the central wavelength of the filters was calibrated by tilting operation, and the sensitivity of detectors was calibrated by referencing the stationary and axially symmetric tungsten inert gas (TIG) arc plasma. We could perform the temperature measurement of the transient and asymmetrical TIG arc plasma such as in the transition period between the peak 150 A and base 10 A current of a 50 Hz pulsed TIG arc with 30°t ilted torch. It was revealed that the high-temperature area of 30°tilted arc is larger than that of perpendicular arc. The comparison of pulsed and continuous arcs shows that the arc shape and the temperature variation reasonably followed the current change as long as the changing rate was about −113 A/ ms.

3D measurement of temperature and metal vapor concentration in MIG arc plasma using a multidirectional spectroscopic method

“…Although there are some studies of plasma diagnostics using the tomographic method [11][12][13][14][15][16][17], no study has shown axially asymmetric diagnostics for MIG arc welding processes. Our previous studies developed a tomographic measurement system for a magnetized deformed TIG arc [18], tandem TIG arc [19], and inclined pulsed TIG arc [20]. Our recent report shows the behavior of argon and iron vapor in MIG arc welding, focusing on the difference of droplet transfer [21].…”

Pulsed arc light monitoring and temperature reconstruction with arc welding

“…Compared with the literature [20-22] and our previous work, the maximum temperature was considered as 19,000 –20000 K during 80 –200 A, and the difference was region scale. Simultaneously, the arc boundary was compared and minimum intensity was recognised as 7000 K at 100 A.…”

Visualization of electromagnetic-thermal-fluid phenomena in arc welding

“…Hiraoka et al 6) compared the temperature distribution of arc plasma measured using various spectroscopic methods, and investigated the quantitative evaluation of plasma characteristics. Konishi et al 7) and Nomura et al 8) evaluated the three-dimensional temperature distribution of non-axisymmetric arc plasma using image reconstruction. Regarding GMA welding, Zielinska et al 9) determined the distribution of electron temperature and electron density by measuring Stark broadening, although only in one dimension.…”