Titanium Corrugated Tube Gr2

Hydraulic forming is suitable for processing pure titanium bellows, it is the use of pumps injected into the billet medium pressure (oil or water), forcing the billet in the restriction of the module expansion, and then removed from the module between the positioning support, the use of hydraulic presses or other similar role of the equipment, compression of the billet to the desired final length, remove the module, and then the forming of the corrugated pipe. The characteristics of hydroforming are: during the forming process, the billet is compressed uniformly and the amount of thinning is moderate. Hydroforming is divided into two types: multi-wave one-time forming and single-wave continuous forming.

Roll forming is to put the billet in the forming machine, through the rotation of the working wheel, the working wheel and the contact surface of the billet to produce friction, and rely on the force to drive the whole billet rotary, and then through the downward feeding of the working wheel, that is, the billet on the gradual formation of bumps, that is, the initial wave. At the same time, the shaping wheel gradually axial close, and slow feeding of the working wheel corresponds to, and finally in the circumference of the billet rolled out U-shaped corrugations. Roll forming can be rolled into one or more ripples each time, suitable for processing larger diameter titanium bellows, but due to the large diameter seamless titanium tube is difficult to produce, the molding method is less used. This method can also be placed on the working wheel outside the tube to reduce the size of the forming, suitable for processing titanium bellows with a diameter of <100 mm.

Spin forming is currently the most widely used method of producing titanium bellows, mainly for the production of spiral bellows. Its mold is composed of a working diaphragm and a spacer. After the billet enters the rotating mold, under the action of the diaphragm and spacer, the billet is extruded in both radial and axial directions, resulting in plastic deformation, and gradually shaped into a spiral corrugated pipe. This method generally produces small titanium bellows, for example, Japan with the production of this method for the diameter of 9. 52 mm ~ 28. 6 mm, wall thickness of 0. 3 mm ~ 0. 7 mm, tube length of 6 m within the titanium bellows.

Expansion forming is pre-installed in the billet with a circular internal mold, the mold is composed of a number of flaps of the module combination, the center of the internal mold has a cylinder to promote the up and down movement of the cone. When the cone down, on the block to produce side pressure, in the force, the module to make the billet by the expansion of the waveform, the cone up after the module by the spring force reset.

Welding is the use of precision welding technology, a number of sheet metal stamping ring diaphragm, alternately welded along its inner and outer edges of the tubular shell with transverse corrugated welded into shape. Its characteristics are: as a result of welding bellows in the manufacturing process, wall thickness and other geometric dimensions are easy to control, so it works better for the production of high-precision bellows; axial compensation is quite large, the maximum can reach 80% of the total length of the bellows, but not pressure-resistant, and the production of high-cost, mostly used for larger sizes, requires a large amount of compensation for the low-pressure titanium bellows. Welding process generally used argon arc welding and plasma arc welding.

Superplastic forming is a new bellows forming process, mainly using many titanium alloys such as Ti- 6Al - 4V in the supply state that has superplastic properties of this feature to form the wave depth parameters of titanium alloy bellows. Forming blanks are seamless titanium alloy tubes or welded cylinders made by high-energy beam welding (plasma arc welding, laser welding and vacuum electron beam welding), and the diameter of the titanium alloy bellows that can be produced depends only on the capacity of the superplastic forming machine, which is generally 50-800 mm. The forming process adopts the composite forming process of superplastic pneumatic expansion and axial loading, which is made up of three phases: the expansion phase, the clamping phase and the filling phase.
Super-plastic expansion process is as follows:
(1) Expansion stage: The press does not move, filling argon gas in the billet, so that the billet to produce the appropriate plastic deformation, even if the billet slightly bulging, can make the middle of the template is fixed in the cylinder.
(2) Close the mold stage: Open the press down, press the module.
(3) Filling stage: Continue to press and hold pressure for a period of time, so that all parts of the formed bellows tightly molded. The dimensions of the superplasticized bellows are accurate and there is no residual stress. The disadvantage is that the molding process is a hot process, energy consumption is higher, and the unevenness of wall thickness of the formed parts is higher than that of the hydroformed parts.