Low temp. and low pressure reaction type diffusion welding for aluminium and copper sheets

Abstract

The present invention relates to a low-temp. low-pressure diffusion welding process of aluminium-copper dimetal sheet, and is characterized by that said welding process has no need of adding any intermediate layer, and utilizes Al-Cu-Mg three-component cocrystallization reaction between Al-Mg system alloy and Cu to form liquid phase and connect them together, its temp. is 470 deg.C-520 deg.C, time is 3 min-10 min., pressure is 3MPa-5Mpa and the degree of vacuum is 1X10 to minus second Pa-1X10 to the minus third Pa. Before welding, the surfaces of Al-Mg alloy and Cu have no need of strict surface treatment, only have need of removing greasy dirt, oxide and other impurity from their surface by using mechanical grinding process. Its operation is simple and its welding efficiency is high.

Description

technical field [0001] The invention relates to a low-temperature and low-pressure diffusion welding of an aluminum-copper bimetal sheet used for aluminum-copper metal materials. Background technique [0002] For the welding process of aluminum-copper bimetallic materials, methods such as friction welding, cold pressure welding, explosive welding, brazing and solid phase diffusion are currently used. Among them, friction welding is only suitable for the butt joint structure of aluminum and copper bars. For aluminum Welding of copper sheets cannot be used; brazing has a great influence on the joint performance of aluminum-copper materials; and explosive welding and cold-press welding are not suitable for ultra-small aluminum-copper due to factors such as difficult control of process parameters and easy deformation of workpieces. Welding of bimetal sheets; although solid-phase diffusion welding has a good welding effect on aluminum-copper bimetal materials, its welding time is...

AI Technical Summary

Problems solved by technology

[0002] For the welding process of aluminum-copper bimetallic materials, methods such as friction welding, cold pressure welding, explosive welding, brazing and solid phase diffusion are currently used. Among them, friction welding is only suitable for the butt joint structure of aluminum and copper bars. For aluminum Welding of copper sheets cannot be used; brazing has a great influence on the joint performance of aluminum-copper materials; and explosive welding and cold-press welding are not suitable for ultra-small aluminum-copper due to factors such as difficult control of process parameters and easy deformation of workpieces. Welding of bimetal sheets; although solid-phase diffusion welding has a good welding effect on aluminum-copper bimetal materials, its welding time is longer, welding pressure is higher, and welding temperature is higher. The surface preparation is generally more demanding, and the oxide film and pollutants should be removed as much as possible in advance, and the roughness of the contact surface must match the selected process parameters to achieve reliable metal-to-metal contact on the surface of the weldment. There are strict requirements on the surface cleaning and roughness of the workpiece to be welded. Usually, the welding temperature of aluminum-copper diffusion welding is above 520°C, the welding pressure is 5MPa-10MPa, and the holding time is 10min-30min. The weldment must also be welded Before rigorous cleaning and maintain a high roughness