Aluminum alloy and steel optimized welding method based on magnetic control resistance spot welding

Abstract

An aluminum alloy and steel optimized welding method based on magnetic control resistance spot welding comprises the steps that a steel plate and an aluminum alloy plate are arranged between an electrode and a controllable magnetic field, Joule heat is generated in the steel plate by applying welding current, and the temperature of the side, close to the steel plate, of the aluminum alloy plate is evenly increased through the blocking effect of a high-resistivity oxidation film between the steel plate and the aluminum alloy plate; and the side, close to the steel plate, of the aluminum alloy plate is molten to form molten aluminum alloy, the molten aluminum alloy flows and is stirred at a high speed under the action of Lorentz force generated by a magnetic field and current, aggregation of oxide film defects near an interface is inhibited, and thin and uniform intermetallic compounds are formed by heterogeneous materials on the two sides of the interface. By heating a steel side resistor, the heat input of the aluminum side is reduced, the thinning of the aluminum plate is reduced, the surface indentation of the aluminum plate is eliminated, and the thickness of an interface intermetallic compound layer is controlled; and lorentz force is generated through interaction of an external magnetic field and current, molten aluminum alloy is driven to flow at a high speed, the aluminum side nugget structure and defect distribution are improved, and the mechanical performance of a welded joint is improved. By avoiding direct contact between a copper electrode and an aluminum plate, electrode abrasion is reduced, and the performance, appearance quality and welding spot quality stability of an aluminum steel spot welding joint are improved.

Description

technical field [0001] The invention relates to a technology in the field of welding, in particular to an optimized welding method for aluminum alloy and steel based on magnetron resistance spot welding. Background technique [0002] The mixed use of aluminum alloy and steel is an important means to reduce the weight of the car body and realize energy saving and emission reduction. Resistance spot welding is the main process for manufacturing thin-walled structures of vehicles such as automobiles and rail transit carriages. However, the thermal conductivity, resistivity, thermal expansion coefficient and other properties of aluminum alloy and steel are quite different. During resistance spot welding, the aluminum alloy is seriously thinned due to its low melting point, and the quality of the joint is difficult to guarantee. Marks are obvious and the surface quality is poor. The traditional resistance spot welding of aluminum alloy and steel tends to form thicker intermetal...

AI Technical Summary

Problems solved by technology

However, the thermal conductivity, resistivity, thermal expansion coefficient and other properties of aluminum alloy and steel are quite different. During resistance spot welding, the aluminum alloy is seriously thinned due to its low melting point, and the quality of the joint is difficult to guarantee. Obvious marks, poor surface quality

The traditional resistance spot welding of aluminum alloy and steel tends to form thicker intermetallic compounds and oxide film defects at the interface of dissimilar metals, which seriously affects the mechanical properties of solder joints

In addition, because the aluminum alloy is easy to react with the copper electrode, the electrode on the aluminum side is severely worn and the quality of the solder joint is unstable.

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