Tantalum tube manufacturing process

Tantalum cannot be processed in the same way as ordinary metals. Generally, the initial process is forging and heat treatment, which is used to make flat billet or round medium and small billet by hammering and stamping.

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Tantalum cannot be processed in the same way as ordinary metals. Generally, the initial process is forging and heat treatment,

The plate blank or round medium and small blank is made by hammering and stamping. Unlike ordinary metals, tantalum cannot be hot worked. If the recrystallization temperature of tantalum exceeds 1000 ~ C, excessive oxidation will occur even if the general protective coating is applied. What's more, if tantalum is exposed to such a high temperature, not only excessive oxidation will occur on the surface of tantalum, but also oxygen will invade into the atoms inside the matrix, making tantalum brittle. Not only oxygen, but also nitrogen, carbon and hydrogen can make tantalum brittle. Due to the above reasons, tantalum is generally not hot processed. When hot working is necessary, protective coating or inert gas atmosphere should be used.

heat treatment

Because of the active reaction between tantalum and oxygen, it is necessary to avoid the atmosphere with little air

Heat treatment. Therefore, almost all annealing is carried out in a high vacuum, and the air tightness of the furnace must be very high. Generally, the heat treatment temperature of tantalum is 950 ~ 1300 ℃. Tantalum and other commonly used Tantalum Alloys do not undergo phase transformation in this temperature range. The heat treatment is only used for annealing, so the heating temperature and cooling rate are not important. In order to produce complete recrystallization, a longer heat treatment time is better.

Tantalum is commercially produced with high purity. The grains become very large by annealing. The size of crystallite is determined by cold working, purity, temperature and process steps. Therefore, temperature control and process control are important means to determine the crystal size.

Tantalum, unlike many other metals, must be very clean before heat treatment. If it is not cleaned very well, the surface pollution caused by hydrogen, oxygen, nitrogen and carbon will occur and become brittle (hardening) structure. Because hydrogen, oxygen, nitrogen and carbon are very active intrusive elements in the temperature range of tantalum annealing, once they are polluted by these elements, they can not be removed except by remelting.