PURPOSE: To simplify the connection and disconnection of pipes and as well to make it possible to repeatedly use the pipes, in a method of connecting pipes more than two in number with the use of shape memory alloy, by making the shape memory alloy have a remarkable reversibility with the use of an ageing treatment under restraining.
CONSTITUTION: A rod-like member 13 is inserted in a cylinder 10 made of water- quenched shape memory alloy at a temperature below a martensitic transformation point (under dipping in liquefied nitrogen) in order to enlarge the diameter of the cylinder 10 so that a cylinder 20 having a diameter which is slightly larger than the inner diameter of a pipe to be connected therewith, is obtained. In a temperature atmosphere less than 600°C the cylinder 20 is shifted onto a retainer tool slightly less than the core rod of the rod-like member 13 under dipping in liquefied nitrogen, and is subjected to an ageing treatment under such a restrained condition that the strain is left to be applied to the shape memory alloy in the cylinder 20. When the retainer tool is removed at a temperature above an reverse transformation point, the diameter of a joint for the cylinder 10 spontaneously repeats expansion and retraction during heating and cooling cycles.
TOITA MASAYUKI
YAMAUCHI KIYOSHI
| JPS5822630A | 1983-02-10 |