The emergence of superplastic forming technology provides a new technical approach for the formation of certain titanium alloys with superplastic properties.
Forming plan includes: forming device, mold material mold structure, heating method, charging method, wall thickness control and protective measures, etc. The main factors that should be considered in determining the forming plan are:

1. The structural characteristics of the parts, such as the size, the complexity of the shape, the smallest arc and its location, etc .;
2. Technical wood requirements, such as shape and dimensional accuracy, wall thickness uniformity requirements and mechanical performance index requirements, etc .;
3. The state of the selected material, such as the type of alloy, the state of thickness structure, etc.,
4. Existing molding conditions, such as molding equipment, heating means and control, detection means, etc.
   According to the above points, consider comprehensively to determine a reasonable plan. The titanium alloy spherical gas cylinder is a spherical part with a diameter of 370mm, which is welded by two hemispheres, and has high requirements on dimensional accuracy, wall thickness uniformity and shape accuracy. Using concave die forming, overall heating, vacuum argon filling, bidirectional forming to control the amount of thinning, the use of 950 ℃ high temperature resistant materials in the mold design, with sufficient high temperature strength, rigidity and dimensional stability.
   The bottom of the ball is a large thin shell with a diameter of 1502mm and a depth of 381mm. There are two steps up and down and a small arc of R = 5mm. According to the domestic production status of titanium rods, the plates need to be welded together, so that large parts cannot be heated integrally. A large-scale internally heated forming device must be designed and manufactured. This device can achieve the clamping of the plate, high temperature tightness Heating and temperature control can achieve argon filling. Slab protection uses a combination of paint and argon filling.
   Titanium foil corrugated board adopts TB 20.25mm TB2 foil material, and the vacuum forming method is adopted for the small size of the material’s sensitivity to hydrogen and oxygen pollution.