Pure tantalum has good plasticity, small deformation resistance and low processing hardening rate. All kinds of profiles and shaped parts can be produced by plastic processing method. Pure tantalum can be rolled into sheets, sheets, sheets, sheets, pipes, and bars at room temperature. To reduce oxidation, pure tantalum plastic processing at room temperature or below 500 ℃. Tantalum alloy with high strength and ingot casting low plasticity, must be sufficiently above 1200 ℃, the processing technology of the same as the pure tantalum. The extrusion ratio should be greater than 4 and the forging ratio should be greater than 2. When the billet is heated, the plasticity of the material should be decreased due to gas pollution. Cross rolling is used to ensure good stamping and spinning properties. The rate of cross - rolling should be maintained at about 80%. Tantalum plate can be made into cup, cap, pipe, cone, nozzle and other parts of different shapes by spinning and deep-drawing. The diameter of the rotary forging rod for drawing is generally 2.5mm. Because tantalum is soft, it is easy to bond and scratch the surface of the die, the surface of the wire is often anodized to form an oxide film and lubricated with beeswax before drawing.
Tantalum and its alloy blank can be produced by powder metallurgy process or smelting process. Powder metallurgy technology is mainly used to produce small tantalum products and blank for processing. The raw materials of powder tantalum obtained by thermal reduction or electrolysis were pressed and then vacuum sintered. The sintering process depends on the requirements of the product. A sintering (1600 ~ 2200 ℃) used in the production of smelting with electrodes and the porous anode. Secondary sintering is used to produce blank for forging, rolling and drawing. Forging or rolling is often carried out between sintering, and the processing rate is about 50%. Secondary sintering temperature is 2000 ~ 2700 ℃.
Vacuum consumable arc and electron beam melting process are common methods to make tantalum and its alloy ingots. Electron beam smelting process is mainly used for the purification of tantalum. The consumable arc smelting process can produce ingots with large diameter and more uniform alloy composition. The electrode of consumable arc smelting can be made by sintering rod or electron beam smelting ingot. Electron beam regional melting method can be used to further purify tantalum or prepare single crystal.
