Heat development of the contact area during capacitor discharge welding

Abstract

Capacitor discharge welding primarily applies to projection welding. Components with ring projections up to 200 mm diameter can be welded with peak currents up to 1000 kA and welding times less than 10 ms. Weld nuggets are expected to occur, as the CD-Welding belongs to resistance welding. Although the required strength is given, welding nuggets in cross-sections cannot invariably be verified. According to recent researches, joining occurs without a welding nugget, but with metal vaporisation and linked activation of the surfaces. This process is called short-time welding with high thermal current density. The type of the welded joint depends on the heating properties in the weld zone. Different welding energies, electrode forces and welding times result in different welded joints. The process-specific advantages can be taken, and new application areas for CD welding can be developed by knowing the cause-and-effect relationships.