A method for producing superconducting niobium tube. Its characteristics are, including the following steps: cylindrical high purity niobium ingot for drilling, get hollow ingot, at room temperature on the hollow ingot extrusion to get the tube blank, and then the tube blank rolling, that is, get finished niobium pipe. The invention adopts the pressure processing mode of "room temperature forward extrusion + pipe rolling" to realize the production of pure niobium pipe for superconducting accelerator, and can process high purity niobium pipe with RRR ≥300 under the premise of simple process and no need to make tooling. The present invention uses the room temperature forward extrusion method to squeeze the tube blank, and controls the temperature rise degree of the material in the extrusion process by controlling the extrusion speed, which can effectively avoid the serious loss of RRR value. Multi-roll pipe mill can be used to produce finished pipe with high dimensional accuracy and small ellipticity.
The key parameter of superconducting performance of high purity niobium pipe for superconducting accelerator is RRR value (residual resistivity of material at 4.2K temperature). Generally,RRR value is required to be greater than 300. The higher RRR value, the better superconducting performance of pipe. The main factor affecting the superconducting performance of high purity niobium pipe is the degree of temperature rise during the process from the ingot to the finished product. The higher the temperature rise during the process, the more serious the RRR value attenuation. Therefore, the processing method is very important for the production of pure niobium pipe used in the superconducting accelerator.
Superconducting acceleration is used at present, the global production technology of pure niobium tube sheet welding method, the backward extrusion method, main forging deep reaming method and rafa four categories, but the following drawbacks: (1) sheet of plate straightness, welding technology and welding method roundness by such as the demand is higher, and need to ingot casting processing onto a plate for welding, production cycle is long; 2) The reverse extrusion method requires high precision of extrusion equipment tooling and lubrication system, and the finished products need machining, and the material utilization rate is low; 3) The problems of low material utilization rate, slow production efficiency and high tooling cost exist in forging and deep reaming method. In addition, the above four methods are difficult to achieve the diameter of pipe less than 9 50mm, wall thickness of more than 3mm.
A method of producing superconducting niobium pipe, its special lies in, including the following steps: take cylindrical high purity niobium ingot for drilling, get hollow ingot, at room temperature on the hollow ingot extrusion to get tube blank, and then the tube blank rolling, that is, get finished niobium pipe.
