Automatic wire-feeding friction stir welding method for butt joint of dissimilar metal materials

Abstract

The invention discloses an automatic wire-feeding friction stir welding method for butt joint of dissimilar metal materials. The automatic wire-feeding friction stir welding method comprises the following steps that 1, welding pieces are in butt joint with each other and are clamped, an interval is formed between the welding pieces, strip-shaped welding wires are led out from a wire-feeding gun, a straightening wheel set, a pre-buried wheel and a leveling wheel are sequentially placed on the interval, the strip-shaped welding wires are straightened through the straightening wheel set, then obliquely downwards fed into the interval through the pre-buried wheel and later leveled through the leveling wheel, and the ends of the strip-shaped welding wires are arranged under a stirring head; 2, a welding machine is started, the stirring head starts vertical downwards feeding, later a stirring needle is pressed into the interval where the strip-shaped welding wires are stored, welding is started, and in the welding process, the wire-feeding speed keeps consistent with the welding speed; and 3, the stirring head is lifted, then wire feeding is stopped, and the strip-shaped welding wires are cut off. According to the automatic wire-feeding friction stir welding method for butt joint of the dissimilar metal materials, generation of chemical compounds between metal can be reduced, the interface temperature is decreased, the residual stress is reduced, a welding joint is prevented from generating holes, and the mechanical property and the welding efficiency of welding connectors are improved.

Description

technical field [0001] The invention relates to welding technology, in particular to an automatic wire-feeding friction stir welding method for butt jointing of dissimilar metal materials. Background technique [0002] With the further strengthening of the demand for infrastructure construction in our country, more engineering projects no longer choose a single material, but prefer dissimilar metal composite materials with better comprehensive performance, in which the dissimilar metal connection of aluminum alloy and steel It has broad application prospects and is being gradually applied to more and more industrial production departments such as vehicle manufacturing and ship production. Due to the large difference in physical properties between aluminum alloy and steel, traditional fusion welding techniques such as fusion welding are difficult to obtain welded joints with good shape and excellent performance. However, aluminum alloy and steel can obtain higher strength th...

AI Technical Summary

Problems solved by technology

[0007] CN102941414A discloses a pre-filled wire friction stir welding method, which cladding a layer of metal on the surface of the base metal by TIG or MIG welding during the welding process, followed by friction stir welding to solve the problem of the existing friction stir welding process. The problem of thinning the effective thickness of the weld seam, but only cladding the strip-shaped intermediate layer on the surface of the workpiece to be welded does not improve the strength of the aluminum / steel interface

[0008] CN103157903A discloses a strip-shaped welding wire that can eliminate the thinning of the weld and send it into the friction stir welding method. It is in contact with the end of the strip-shaped intermediate layer and drilled into the base metal, and the welding of the base metal is realized through the stirring and heating action of the stirring pin and the shoulder, so as to solve the problem of thinning of the weld seam that cannot be solved by the traditional friction stir welding technology

However, since the intermediate layer is required to be melted, only pure zinc or zinc-aluminum solder with a low melting point can be used as the intermediate transition layer. Under the action of pressure during the welding process, part of the liquid intermediate transition layer is squeezed out of the welding area, resulting in a thin middle layer. , Both sides are thick, and there are welding defects such as holes and incomplete fusion in the weld

In addition, friction stir lap brazing also has problems such as limited welding thickness and easy wear of the stirring head.

[0010] To sum up, in view of the poor weldability of aluminum alloy and steel, it is urgent to develop a medium and low temperature welding technology that can effectively reduce the thickness of intermetallic compounds at the interface and reduce the interface stress.

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