Nickel-titanium shape memory alloy composite pipe joint forming method

Abstract

The object of the present invention is to provide a method for forming a nickel-titanium shape memory alloy composite pipe joint, comprising the following steps: assembling two layers of nickel-titanium shape memory tubes together in a clearance fit or interference fit mode to form a double-layer pipe, the double-layer pipe The inner diameter d0 of the pipe is smaller than the outer diameter d2 of the two pipes to be connected; the inner diameter of the double-layer pipe is increased to d1 through diameter expansion deformation, so that the two layers of nickel-titanium shape memory pipes are composited into one body, and d1 is larger than the outer diameter of the pipes to be connected Diameter d2; put the pipe joint with expanded diameter on the outside of the two pipes to be connected; the shape of the pipe joint is restored by low-temperature heating, and the pipe joint automatically shrinks to connect the two pipes together to complete the forming. The invention makes up for the deficiency that the wall thickness of the traditional nickel-titanium shape memory alloy pipe joint is too thin or too thick. Alloy pipe joints have excellent connection performance.

Description

technical field [0001] The invention relates to a pipe joint forming method, in particular to a pipe joint forming method in the technical field of precision manufacturing of pipe joint parts. Background technique [0002] Nickel-titanium shape memory alloys have been widely used in engineering fields because of their good shape memory effect and superelasticity. The shape memory effect of shape memory alloy refers to plastic deformation in a certain low temperature phase, and then heated to a certain temperature, the material undergoes a phase change and can return to the state before plastic deformation. The most typical application of nickel-titanium shape memory alloy in shape memory effect is shape memory alloy pipe joint. Nickel-titanium shape memory alloy pipe joints can realize the connection of two pipes, which is different from threaded mechanical connection and welding. In the application of nickel-titanium shape memory alloy pipe joints, the pipe joint whose in...

AI Technical Summary

Problems solved by technology

In particular, the wall thickness of the nickel-titanium shape memory alloy pipe joint is very important to the connection performance of the pipe joint. If the wall thickness is too thin, the strength of the pipe joint is insufficient, and the fastening force cannot meet the use requirements. During the expansion process of the joint, there is a gradient deformation problem, that is, the inner metal has a large deformation, while the outer metal has a small deformation, which will affect the subsequent shape recovery of the nickel-titanium shape memory alloy pipe joint, resulting in fastening Therefore, optimizing the wall thickness of nickel-titanium shape memory alloy pipe joints has always been a research topic in the engineering field.

Images