Investigation of the relationship between voltage and arc length of K-TIG welding under penetrated condition.

Due to the strong requirement of keyhole TIG (K-TIG) welding for arc length stability and the advantages of voltage sensing, it is necessary to discuss the relationship between the voltage and arc length. In this paper, based on several groups of experiments, a nonlinear transition point between the relationship of voltage and arc length was found with increasing arc length. Then, to analyze the formation mechanism of the nonlinear transition, a simplified arc physical model was developed. After considering the variations in the welding parameter, the reduction in arc pressure was found to be the main factor leading to a nonlinear relationship, while the shielding gas flow rate is the most effective parameter. This work lays a foundation for better understanding the welding arc and real-time control of arc length by voltage sensing in K-TIG welding. [ABSTRACT FROM AUTHOR]