Application of a Titanium-Based Shape Memory Alloy as a Room-Temperature Reaming and Preservation Pipe Joint

Abstract

The invention relates to application of a titanium-based shape memory alloy as room temperature reaming and a saving pipe connector. The alloy is smelted and forged into a bar material and then is manufactured into the needed structure and shape in a machined manner. The manufactured pipe joint is broached under the room temperature martensitic phase state, and is heated to the temperature of 200 DEG C or above to be subject to inverse martensite conversion, the pipe connector becomes a parent phase, about 4% shape memory effect recovery is generated, and a connected pipefitting is tied firmly; in the process of cooling the alloy to the temperature of minus 100 DEG C, a reversible martensite phase change is not generated, and the alloy is still kept to be of a parent phase structure, and it is ensured that the pipe joint still has the higher connecting strength at the low temperature of minus 60 DEG C. In the broaching and storing process of the pipe joint, the liquid nitrogen environment is not needed, the density is lower than that of an NiTiFe and NiTiNb pipe joints, weight reduction of a connection system is facilitated, the cost is reduced, and use convenience is improved.

Description

technical field [0001] The invention relates to the application of a titanium-based shape memory alloy as a room temperature reaming and preservation pipe joint, and is used as a new pipe joint for connecting with various pipe fittings in the fields of aerospace, aviation, refrigeration and energy. Background technique [0002] At present, the shape memory alloy pipe joints used in the fields of aerospace, aviation, refrigeration and energy are all made of Ni-Ti-Fe (such as CN1614056A) or Ni-Ti-Nb (such as CN105132749A) alloy. In order to ensure the stability of pipe joints made of these alloys at low temperatures (generally -55°C), the phase transition temperatures of Ni-Ti-Fe and Ni-Ti-Nb alloys are generally -150 to -60°C; Ni- Both Ti-Fe and Ni-Ti-Nb alloy pipe joints must be reamed at low temperature before use. The typical reaming temperatures are -196°C (liquid nitrogen temperature) and -65°C (liquid nitrogen + ethanol temperature), and The reamed Ni-Ti-Fe alloy pipe ...

AI Technical Summary

Problems solved by technology

In the process of use and storage, these two types of pipe joints require a liquid nitrogen environment, which not only increases the cost, but also seriously limits their scope of use.

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