A Control System for Keyhole Plasma Arc Welding of Stainless Steel Plates with Medium Thickness

作者：Wu C S^*; Jia C B; Chen M A

来源：Welding Journal, 2010, 89(11): 225S-231S.

• Plasma Arc Welding
• Keyhole
• Control System
• Pulse Current Waveform
• Efflux Plasma Voltage
• Stainless Steel Plates
• Medium Thickness

Keyhole plasma are welding (PAW) has the potential to achieve deep, narrow penetration with low cost and high tolerance of joint preparation. However, the narrow parameter window associated with the keyhole condition limits its wide application, especially for welding thicker plates. To reach its full potential, a control system for keyhole PAW is developed. The offlux plasma voltage signal is detected in real-time to characterize the keyhole size and dimension. The welding current waveform with two slow dropping substages and variable slope is designed to improve the controllability of keyhole dynamics via reducing both heat input and arc force when a keyhole transforms from its opening status to the closure status. The keyhole PAW experiments are conducted to examine the control effectiveness of the system. The developed system operates in the mode of "one keyhole per pulse" reliably. Closed-loop control tests of varied-thickness plates show that even if the plate thickness changes as much as 50% (from 8 to 4 mm), the developed system adjusts the peak current and its dropping slopes automatically to keep both weld width and penetration consistent.

• 出版日期2010-11
• 单位山东大学