Processing method for large size tantalum or tantalum alloy seamless pipe. It is characterized by the following steps: the first step: the tantalum or tantalum alloy ingot cut hole, get hollow tube blank; The second step: tube billet extrusion, that is, the hollow tube billet preheated to 150-230℃, and then heated by intermediate frequency furnace after extrusion into a diameter of 90-130mm tube billet, tube wall thickness of 10-25mm, extrusion temperature of 800℃-900℃; The third step: the obtained tube blank will be pickled to remove surface impurities. The invention provides a processing method for large-size seamless pipe, which is mainly suitable for the production of large-diameter thick-wall pipe with anticorrosive outer diameter ≥φ60-90mm and wall thickness ≥3-6mm in chemical industry. With appropriate heat treatment process, the required performance of the product can be obtained and the utilization rate of the material can be greatly improved.
Pure tantalum and tantalum tungsten alloy is a kind of high density, high melting point, high intensity of rare metal materials, has the very high temperature strength, good ductility, weldability and corrosion resistance, suitable for high temperature and high pressure, corrosion resistance and so on work environment, in the chemical anti-corrosion industry develops very fast in recent years, is a kind of very important engineering and functional materials. The excellent corrosion resistance of tantalum and tantalum tungsten alloys is due to the formation of a very thin, impermeable and protective layer of Ta2O5 oxide on the metal surface. This layer is resistant to strong alkali, HF, chloride and sulfuric acid corrosion up to 190°C -- 250°C. The structure of the film varies with the environment. Ta-2.5%w alloy is characterized by not only improving the strength of the material itself, but also has good corrosion ability. The comparison of immersion test with 96% industrial sulfuric acid and recycled nitrifying waste acid shows that the corrosion resistance of Ta2.5W in sulfuric acid is better than that of unalloyed tantalum. When the sulfuric acid concentration reaches above 96%, ta2.5W material is mainly used.
It provides a processing method of large size tantalum or tantalum alloy seamless pipe, which can meet the quality requirements of large diameter thick wall pipe products and significantly improve the material utilization rate.
