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All-titanium container: An all-titanium container refers to one in which the main components, such as the shell, head, and nozzles, are made of titanium, while the secondary components need not be made of titanium; for example, the swivel flanges and their connecting bolts can also be made of carbon steel. The minimum thickness of the all-titanium container shell is 2 mm, which is primarily intended to meet the thickness requirements of welding processes during manufacturing, as well as the requirements regarding geometric dimension tolerances. It also ensures the stiffness necessary for manufacturing, transportation, and lifting ； As well as saving titanium material and reducing costs. Design selection principles: Since the mechanical strength of titanium decreases significantly at temperatures of 200°C or higher, and its elastic modulus is low as well, all-titanium structures are not suitable for use in high-temperature, high-pressure, or medium-pressure environments, as well as in large-scale equipment. The allowable temperature for all-titanium pressure vessels should not exceed 250°C, and it is considered that for small and medium-sized vessels operating at a pressure of 0.5 MPa and at temperatures below 150°C, an all-titanium structure is a more economical choice. Considering investment costs, using pure titanium may not be economical when the thickness is greater than 13 mm. Structural requirements: Although fully titanium containers have a structural design that is somewhat similar to that of stainless steel, the special properties of titanium itself result in unique considerations in terms of design and manufacturing. Therefore, the following points must be taken into account during structural design: 1) When designing welded structures, it is necessary to ensure that the welding areas are suitable for welding with hydrogen arc welders, and that all welding joints exposed to high temperatures (above 400°C) are properly protected. In its molten state, titanium can react chemically with almost any element; therefore, special protection measures must be taken during welding and heat treatment processes. To achieve effective protection, the structural shape of the components should be simple, and the openings in the housing for connecting pipes should be as vertical as possible with respect to the axis of the housing, so as to facilitate the fabrication of the protective fixture and improve the level of protection. 2) Strictly avoid welding structures where steel and titanium intermelt. Since other metals such as iron, when melted into titanium welds, form hard and brittle intermetallic compounds that greatly reduce the plasticity of the welds, titanium and steel cannot be welded together except through explosive welding or brazing. 3) The root gap of the butt weld joint should be appropriate. The root gap of the butt weld joints in all-titanium pressure vessels is smaller than that in steel, due to titanium’s high melting point, poor thermal conductivity, low heat capacity, high electrical resistivity, and high fluidity of the molten metal in the weld pool. 4) The design of titanium containers should ensure structural continuity and a smooth transition at welding joints, while minimizing stress concentration. 5) For bending and flanging titanium components, a larger bending radius should be used (compared to steel), and a smaller expansion ratio should be employed when expanding tubes. 6) Industrially pure titanium is prone to crevice corrosion in certain media; when designing and fabricating containers that come into contact with such media, it is necessary to avoid the formation of crevices and areas of stagnant flow. At these crevices, titanium alloys resistant to crevice corrosion (such as titanium-palladium alloys) or coatings should be used. 7) When designing and manufacturing containers that come into contact with conductive corrosive media, if it is found that contact between titanium and other metals can lead to galvanic corrosion, structural measures should be taken (such as using a third material as a transition layer) or anodic protection should be employed. 8) When designing equipment prone to corrosion, the flow velocity of the corrosive medium should be below the critical flow velocity, and sudden changes in flow velocity or direction should be avoided as much as possible ； Or install protective shields in areas prone to corrosion and abrasion. ①When the medium is corrosive or abrasive and ρv2>740 kg/(m·s2), or when the medium is neither corrosive nor abrasive but ρv2>2355 kg/(m·s2) (where ρ is the density of the medium in kg/m3 and v is the linear velocity of the material flow in m/s), an anti-erosion plate should be installed at the material inlet. ②A protective plate should be installed when the corrosive medium enters the equipment tangentially, or when the inlet pipe is aligned directly with the device wall at a distance of less than 2 times the outer diameter of the pipe.