Connecting method for aluminum-steel dissimilar materials

Abstract

The invention discloses a novel connecting method for aluminum-steel dissimilar joints and relates to a connecting method for aluminum-steel dissimilar materials. The connecting method is characterized in that alloy interlayer adding and mechanical inlaying are combined to achieve connection between aluminum-steel dissimilar materials. The method comprises the steps of cleaning the contact surface and the periphery of a part to be welded; using an organic solvent or a cleaning agent for wiping; surfacing uniformly-distributed columns on the contact surface of a steel part through steel welding wires; depositing a nickel base alloy layer on the contact surface of the steel part through nickel base alloy welding wires; surfacing uniformly-distributed nickel base alloy columns on the surface of the nickel base alloy layer through nickel base alloy welding wires; and surfacing an aluminum layer on the nickel base alloy surface, and performing further machining molding on an aluminum-steel joint. According to the connecting method, the defects of embrittlement of connecting joints, low connecting strength and the like caused by inter-metallic compounds during aluminum-steel welding are overcome, and the problem of failure of joints caused by overlarge differences of heat expansion coefficients of aluminum-steel materials is solved.

Description

technical field [0001] The invention relates to the field of welding technology, in particular to a method for connecting dissimilar materials of aluminum and steel with simple operation, good welding effect and fast manufacturing based on cold metal transition arc. Background technique [0002] As we all know, in order to meet the needs of high strength, light weight, and corrosion resistance of product structures, the connection of aluminum-steel dissimilar materials has been widely used in automobile manufacturing, mechanical parts, building structural materials, aerospace and other fields. However, when aluminum-steel materials are welded, brittle intermetallic compounds are easily formed at the interface, which will greatly reduce the connection strength of the joint; the wettability of liquid aluminum on the steel side is not good, which will affect the aluminum on the steel layer. The spread of the surface reduces the stability of the welding process and causes poor w...

AI Technical Summary

Problems solved by technology

However, when aluminum-steel materials are welded, brittle intermetallic compounds are easily formed at the interface, which will greatly reduce the connection strength of the joint; the wettability of liquid aluminum on the steel side is not good, which will affect the aluminum on the steel layer. The spread of the surface reduces the stability of the welding process and makes the weld poorly formed; in addition, the difference in physical and chemical properties such as the thermal expansion coefficient of aluminum and steel will also cause the welded joint to fail under extreme working conditions

[0003] At present, the main ways to realize the connection of aluminum and steel are as follows. One is to add brazing flux, brazing filler metal or alloy components, etc., so that a transition layer is formed between the aluminum and steel interfaces during welding, reducing the generation of brittle compounds between aluminum and steel, thereby Realize the welding of aluminum-steel joints, such as MIG fusion brazing, brazing, flux cored wire welding, resistance spot welding, laser powder filling fusion brazing, etc., but such methods have problems such as high welding costs and unstable joint performance; The second is to rely on hot rolling, cold pressing and other methods to combine aluminum and steel at the interface under the action of heat and force, such as hot rolling and welding. This method has low production costs, but inclusions are likely to exist at the interface of aluminum and steel. Reduce the combination of aluminum-steel interface, and the service life is short; the third is to adopt the method of mechanical connection, relying on rivets, bolts, etc. to realize the connection between aluminum and steel, but this method has problems such as poor sealing and low reliability

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