Projection welding method of double pulse high capacity capacitance for energy storage

Abstract

Disclosed is a method for double-pulse high capacity condenser energy storage projection welding in the field of welding technique, which contains: overlapping and locating the two low-alloy steel workpieces on the static lower-electrode, the upper-electrode down to compact the joint of workpieces, charging the condenser bank to Uc1, after first-time discharging to welding transformer by the closure of the commutator and the trigger of thyristors which are controlled by a program, breaking the commutator; cooling, and charging the condenser bank to Uc2, and generating the second-time discharging to welding transformer by the closure of the commutator and the trigger of thyristors; breaking the commutator after the energisation, releasing the upper-electrode after constant pressure-maintaining, and the welding process being completed. The invention realizes welding and tempering double-pulse welding in the energy storage resistance projection welding, especially applies to the point welding (projection welding) of thick low-alloy steel, and it has a key action to the joint strength, the joint tenacity and the surface quality. And, compared with other resistance welding power, it decreased the capacity requirement to the power of live wire entanglement.

Description

technical field [0001] The invention relates to a method in the field of welding technology, in particular to a double-pulse large-capacity capacitor energy storage projection welding method. Background technique [0002] In automobile production, in order to reduce the overall mass of the automobile and save energy consumption during the operation of the automobile, more and more low-alloy medium-high-strength steels are now used. Since the resistance projection welding or spot welding process is often used in the assembly of automobile body and parts, compared with ordinary low carbon steel, the resistance welded joint of low alloy steel often has the phenomenon of decreased toughness and increased brittleness. At present, the commonly used AC single pulse resistance point (convex) welding method is used to weld low alloy steel, not only the surface quality of the joint is low and the toughness is poor, but also the grid power required for welding workpieces with large con...

AI Technical Summary

Problems solved by technology

Since the resistance projection welding or spot welding process is often used in the assembly of automobile body and parts, compared with ordinary low carbon steel, the resistance welding joint of low alloy steel often has the phenomenon of decreased toughness and increased brittleness.

The AC single-pulse resistance point (convex) welding method commonly used at present is used to weld low-alloy steel, not only the surface quality of the joint is low, the toughness is poor, but also the grid power required for the workpiece with a large welding contact surface is relatively large.

[0003] After searching the existing technical literature, it was found that Yang Siqian et al. wrote an article "Experimental Research on Double Pulse Spot Welding of TC3 Titanium Alloy" in "Aviation Manufacturing Technology" 2002 (11). A large amount of titanium martensitic structure is produced in the welded joints and heat-affected zones, which significantly reduces the plasticity of the joints. Heat treatment of the spot-welded joints with the second pulse can improve the plasticity of the joints, but this paper uses conventional The power frequency AC spot welding machine can only be used for spot welding of steel plate thickness and small welding area

The large-capacity capacitor energy storage projection welding method can generate concentrated heat, ensure the strength of joints with thick plates and large welding areas, and has low requirements on the input power of the grid. See the research and application of double-pulse large-capacity capacitor energy storage projection welding method