The TC4 titanium pipes on the market are mainly high-strength thick walled pipes produced by hot extrusion or oblique perforation methods. This warm rolling process requires an improvement on the traditional rolling mill by installing an induction heating device on the rolling mill. This processing equipment has a complex structure, complicated process, and high production cost. The main reason for the current situation is the high strength of TC4 titanium alloy and the difficulty of cold rolling forming. To solve the key technology of TC4 seamless tube cold rolling forming, titanium tube manufacturers have jointly conducted a series of studies. If the direct cold rolling forming process is used to produce high-strength titanium alloy pipes, it not only greatly reduces production costs, but also meets the requirements for high-performance applications of titanium alloys.

By using different deformation methods to open the billet, the billet is rolled into a pipe with a total deformation of 70% through two and three passes of rolling, respectively. Perform 800 ℃ × 1h vacuum annealing between passes, and the cooling method is to cool the furnace to 500 ℃ and then air cool it to room temperature to observe the changes in its microstructure and properties. The conclusion drawn is:

In the case of small deformation, the deviation of wall thickness is small and the surface roughness gradually decreases; The large deformation of the billet results in a large deviation in wall thickness, which will affect the wall thickness deviation of the pipe obtained from subsequent passes of rolling.

When the total deformation is the same, the more rolling passes, the greater the elongation and hardness of the pipe, and the higher the strength. Good overall performance.

When rolling with large deformation, the material flows in a strip shape, while when rolling with small deformation, the material flows in a bundle shape. Under the same heat treatment conditions between passes and subsequent rolling processes, the microstructure distortion of the pipe obtained by cutting with large deformation is more severe.