Spatter reduction in GMAW of stainless steel sheets using CBT process

Abstract

In non-pulsed gas metal arc welding (GMAW), spatter can be reduced by lowering the short-circuit current to a low level just before the re-arcing. The controlled bridge transfer (CBT) process, which optimizes accuracy of predicting the re-arcing in real time in response to the molten metal transfer, realizes stable, low spatter level. In this paper, the methods for controlling short-circuit transfers to minimize spatter and to realize stable arcs in GMAW of stainless sheet using argon-rich shielded gases are investigated. The new CBT process has been developed by applying the specific arc length control that is not affected by abnormal rise in arc voltage in argon-rich shielded gas welding. This process can suppress the spatter generation caused by fluctuation in the vibratory motion of the weld pool or inaccurate prediction of the re-arcing in the succeeding short-circuit/re-arcing cycle, and thereby spatter-free GMAW in the short-circuit transfer mode can be carried out even on stainless steels.

Keywords:

• GMA
• welding
• spattering
• short circuit
• stainless steel