Diffusion welding method of dissimilar metal

Abstract

The invention relates to a diffusion welding method of dissimilar metal. A specially designed outer side limiting tool and an inner support tool are adopted for thermal expansion constraint in the welding process of an assembled to-be-welded dissimilar metal part, thus, sufficient and even welding pressure on the radial welding face is obtained, and reliable welding guarantee is provided for diffusion welding of the dissimilar metal. The expansion constraint pressurizing idea is provided by the invention for dissimilar metal interface radial pressurizing, radial expansion of the to-be-welded part is constrained through an inner side limiting tool and the outer side limiting tool, and axial expansion of the to-be-welded part is constrained through axial pressure applied by a diffusion welding device or tool, so that expansion pressure is effectively applied to the welding interface of the dissimilar metal, and the dissimilar metal weld part with good joint performance and airtightness is obtained; and the seaming condition of the whole welding interface is good, obvious concentration gradient of the welding interface exists, and the diffusion characteristic is met.

Description

technical field [0001] The invention relates to a diffusion welding method for dissimilar metals, belonging to the technical field of welding. Background technique [0002] Diffusion welding (Diffusion Welding) is an advanced solid-phase connection technology, which can be used to connect internal multi-point and large-area components, as well as connections with poor arc accessibility, or which are difficult or impossible to achieve by fusion welding. Since the weldment does not melt, diffusion welding technology has a strong advantage in the connection of dissimilar metals, and can obtain welded joints with better overall performance than conventional fusion welding. Welding temperature, pressure and holding time are the main parameters of the diffusion welding process, and the pressure is generally axial pressure. [0003] In order to improve the reliability of the launch vehicle and meet the weight reduction requirements of the valve, the launch vehicle filling valve ad...

AI Technical Summary

Problems solved by technology

Technologies that can realize the large-area connection of aluminum alloy and stainless steel include brazing, explosive welding, diffusion welding, etc. The aluminum-steel brazing joint is not resistant to air corrosion, and the reliability of the joint is relatively low; the process of explosive welding is relatively complicated; "Groove Vacuum Diffusion Welding Process for Cylindrical Connectors" 201310301515.0 patent proposes the use of cylindrical pressure to realize vacuum diffusion welding of grooved copper nozzles. Welding is easier to connect than dissimilar materials, and copper has good plasticity and toughness. It is easier to realize the close fit of the surface to be welded through the small-angle assembly proposed in the patent, but the connection of dissimilar materials is much more complicated. The physical and chemical properties of the two materials are huge. The difference in performance makes it difficult to connect by welding; in the 201310301515.0 patent, the connection between the two can be realized only by the expansion constraint of the copper jacket, and for dissimilar materials, such as aluminum alloy and stainless steel dissimilar materials, only the outer Expansion constraints are simply impossible to achieve a connection between the two

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