With the use of high-strength and hot-formed steel sheets in the automotive and sheet metal industries, the advantages of the capacitor discharge welder for projection welding are becoming more and more apparent. Due to the discharge characteristics of the capacitor discharge welder, which releases a high current in a very short time, it is well suited for projection welding with the same hard specification requirements. The following are the main process adjustments for the capacitor discharge welder:
The main process parameters to be adjusted by the capacitor discharge welder are: charging voltage, welding pressure, forging pressure and tempering voltage; the welding current output of the capacitor discharge welder is changed by the charging voltage setting due to the instantaneous peak discharge of the capacitor discharge welder and the welding time is not used; the charging voltage is proportional to the welding pressure according to the needs of the projection welded products.
When setting the welding pressure and forging pressure, the characteristics of projection welding should be considered. The pressure speed of the bump welding is very important. Too fast a pressure will result in insufficient heat generation to produce a qualified molten core. Therefore, the welding pressure should be sufficient to compact the workpiece in the initial stage, but should not crush it. Forging pressure should follow in time for discharge to ensure both heat generation and the formation of a full molten core under pressure.
Tempering voltage will be used for welding high-carbon steels and materials with a high tendency to quench. The small energy tempering setting refines the thick crystals produced by welding and effectively improves the strength of the welded joint.
