Welding wire special for 7XXX series aluminum alloy and manufacturing method thereof

Abstract

The invention discloses a welding wire special for 7XXX series aluminum alloy and a manufacturing method thereof. The special welding wire is composed of, by mass, 2.0%-6.0% of Ni, 0-5.0% of Mg, 0.1%-0.3% of Zr, 0.1%-0.3% of Ti, 0.1%-0.3% of Cr, 0-0.1% of Fe, 0-0.1% of Si, and the balance Al. The manufacturing steps comprise burdening, smelting, sampling analysis, semicontinuous casting, homogenizing heat treatment, extruding, wire drawing, surface treatment, cleaning, drying and packaging. According to the welding wire, the element Ni which can be subjected to the eutectic reaction with the Al is selected, so that the hot tearing tendency of welds is reduced by forming eutectic structures. The welding wire is suitable for all 7XXX series aluminum alloy and is mainly specific to welding of the high-strength 7XXX series aluminum alloy with poor welding performance. By adopting the welding wire for fusion welding of the 7XXX series aluminum alloy, welding cracks can be effectively avoided, and the weldability of the high-strength 7XXX series aluminum alloy is improved. Through proper heat treatment of welding joints, the strength of the welds is not lower than 260 MPa, and elongation is not lower than 3%.

Description

technical field [0001] The invention belongs to the technical field of aluminum alloy processing, and in particular relates to a special welding wire for 7XXX series aluminum alloys and a manufacturing method thereof. Background technique [0002] The 7XXX series aluminum alloys are mainly Al-Zn-Mg series and Al-Zn-Mg-Cu series aluminum alloys, which have high strength and are widely used in aviation, aerospace, weapons, transportation and other fields. Some medium-strength 7XXX series aluminum alloys that do not contain copper, such as 7017, 7020 and 7039, have no crack defects in the welded joints during fusion welding, and the strength of the heat-affected zone of the weld is reduced, but it can be restored by appropriate heat treatment. The weld strength is 245-300MPa, elongation 2%-10%; some high-strength 7XXX series aluminum alloys with copper content greater than 1%, such as 7022, 7075, etc., are prone to thermal cracks or stress corrosion cracking in welded joints du...

AI Technical Summary

Problems solved by technology

This welding wire is a low-hydrogen fine-grained aluminum alloy welding wire suitable for rail vehicles. The aluminum alloy body of rail vehicles mostly uses 6XXX and 7XXX aluminum alloys, but this welding wire is not suitable for welding all 7XXX series aluminum alloys, especially for copper-containing alloys. High-strength 7XXX series aluminum alloys with a content greater than 1% are not effective, and cracks are likely to occur in welded joints

[0004] In order to further improve the weld strength of 7XXX series aluminum alloys and solve the problem of cracking of welded joints of 7XXX series aluminum alloys with copper content greater than 1%, it is necessary to develop a special welding wire material for welding 7XXX series aluminum alloys

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