2009 Volume 27 Issue 3 Pages 215-221
It hasn't been well known which heat of joule and arc discharge is dominant factor in flash welding process. The objective of this study is to clarify heating mechanism of flashing. The flashing is a cycle consisting of local contact, joule heating, melting, spattering and arc discharge. Numerical model of flashing cycles was developed by assuming initial contact conditions. It has been evaluated heat input and welding parameters of DC flash welding. As the results, arc discharge heat is higher than joule heat for a wide range of flash current. Optimum flashing of DC is large contact and low frequency compared with general continuous flashing of AC. Heat input and platen velocities are 50% higher than those of AC at the same conditions and welding quality. The calculated velocities and crater depth of DC flashing are in good agreement with hot-billets welding data. It was found that DC flash welding compares very favorably with AC for short-time welding.
