Development of a new technological scheme to produce NiTi seamless tubes

In the present study a new technological scheme for the production of seamless tubes from Ti-50.7 at.% Ni shape memory alloy is performed. The initial shell is obtained from the NiTi rod by electrical discharge method allowing to decrease metal consumption. Plugging of the shell is carried out on a screw rolling mill. The deformation-temperature regimes of a shell plugging on a floating mandrel is described in detail. With the application of developed technological scheme NiTi seamless tubes with various outer diameters from 40 to 27.5 mm and a tube schedule from 10 mm to 4.0 mm were produced. The analysis of mechanical and functional properties of obtained tubes reveals that they are quite stable and comparable with properties of initial SMA rods. The suggested technological scheme of NiTi seamless tubes production is promising in terms of simplified processing and potential cost reduction.