Aluminum-steel brazing method

Abstract

The invention discloses an aluminum-steel brazing method which comprises the following steps: firstly chromizing the surface of an aluminum material, then taking an aluminum-based welding flux as a filling material, and connecting the aluminum material with a chromized layer and a steel material by a brazing process. The aluminum-steel brazing method provided by the invention is simple, convenient, low in cost and easy to operate, and solves the problems that an aluminum-steel fusion welding and pressure welding process is complicated, high in cost and hard to precisely control; a brazing flux is not needed to be used, so that the interface of an aluminum-steel brazed joint contains almost no impurities generated by the brazing flux, and is high in cleanness; no AlFe fragile compounds are generated on the aluminum-steel welding interface, so that the intensity of an aluminum-steel joint is improved; the tensile strength is 182 to 205MPa, and the shear strength is 131 to 146MPa; the aluminum-steel brazed joint with uniform welding line tissues and excellent mechanical properties can be obtained; and efficient and reliable connection of aluminum-steel heterogeneous metals is realized.

Description

technical field [0001] The invention relates to a welding method, in particular to a brazing method for connecting dissimilar materials of aluminum and steel. Background technique [0002] Aluminum-steel connection is one of the difficult problems in the field of welding due to the low solid solubility and large difference in thermophysical properties between the two. At present, aluminum-steel connection methods are roughly divided into two categories: one is pressure welding, mainly friction welding, diffusion welding, explosive welding, etc. This method is beneficial to the welding of steel, aluminum and aluminum alloys, and the connection surface must be thoroughly cleaned before welding , Eliminate oxides and films, but the disadvantage of this method is that the shape of the weldment is limited to a certain extent, and the joint has a certain deformation; the other type is fusion welding, mainly argon arc welding, carbon arc welding, electron beam welding, etc. Method...

AI Technical Summary

Problems solved by technology

At present, aluminum-steel connection methods are roughly divided into two categories: one is pressure welding, mainly friction welding, diffusion welding, explosive welding, etc. This method is beneficial to the welding of steel, aluminum and aluminum alloys, and the connection surface must be thoroughly cleaned before welding , Eliminate oxides and films, but the disadvantage of this method is that the shape of the weldment is limited to a certain extent, and the joint has a certain deformation; the other type is fusion welding, mainly argon arc welding, carbon arc welding, electron beam welding, etc. method; using this method, a layer of transition metal must be coated on the steel surface, and this metal must be well combined with aluminum to obtain a good joint

In short, with the fusion welding method, a large amount of brittle compounds are likely to be produced during the welding process, which seriously deteriorates the quality and performance of the joint; with the pressure welding method, the size of the workpiece and the shape of the joint are strictly limited, the process conditions are complex and harsh, and the equipment is expensive

[0003] Patent 201310171686.6 discloses the cold metal transition welding method (CMT) of aluminum-steel dissimilar materials through the nickel interlayer, which uses the nickel cladding layer to improve the aluminum-steel connection interface and improve the joint strength, but the CMT welding machine of this method is expensive, and the nickel-based alloy column The accuracy is not easy to control, which affects the connection quality and performance of aluminum-steel joints

Aluminizing on the surface of steel can realize the connection of aluminum-steel dissimilar metal materials, but the strength of the joint is low, which cannot guarantee the actual application requirements of the aluminum-steel connection.

Therefore, there is still no good aluminum-steel brazing connection method