Visualizations of 2D Temperature Distribution of Molten Metal in Arc Welding Process

In the present research, a general-purpose method for measurement and visualization of the temperature distribution of an object in arc welding, such as a tungsten electrode and a weld pool in GTA welding, and also a metal droplet and a weld pool in GMA welding, was conducted. Two-color pyrometry is utilized to obtain the temperature of the object. The object is photographed by high speed camera during arc welding. Two wave lengths (950 nm and 980 nm) in the infrared range are selected from the thermal radiation emitted from the object by using an imaging spectroscope, and the temperature is obtained from the intensity ratio of the two waves of radiation. Consequently, it was seen that in CO 2 arc welding, the 2D temperature distribution of the metal droplet is not uniform, namely, ranging from 2000 K to over 3000 K, while the 2D temperature distribution of the weld pool is more uniform, about 1800 K. It was found that there is a great difference between the temperature of the metal droplet and that of the weld pool in GMA welding process.