NUMERICAL SIMULATION AND MEASUREMENT OF MAGNETIC FIELD IN ARC WELDING

Recently, the human exposure to electromagnetic fields has become an important problem. A magnetic field is established due to the welding current during welding. Generally, the welding cable is not parallel to the return welding cable depending on the layout of the work place. Moreover the welding current is over 300 A. Pulsed welding current is used in MIG welding for aluminium and stainless steel. But, in the welding system, the measurement becomes unstable due to the effect of the metal plates. In order to evaluate the effect on a magnetic field due to the welding current and the metal plates, numerical simulations and measurements are carried out. The authors use an electromagnetic equation to make the simulation. Since the welding current frequency is low and the arc voltage is less than 50 V, the wavelength of the electromagnetic wave becomes long and the effect of the electrical field is small. The magnetic flux was calculated in the transient state. An L-shaped, 900 mm wide metal plate is considered as the work space size for the calculation and the measurement The comparison between 1998 ICNIRP guideline and magnetic flux density was carried out The hazard area related to human exposure in the L-shaped metal plate was estimated.