Method for preparing high-purity niobium wire for nuclear fuel from general industrial niobium rod as raw material

Abstract

The invention provides a method of preparing high-purity niobium wire for nuclear fuels with a general industrial niobium bar as a raw material. The method comprises the following steps: 1, carrying out electron beam melting on the general industrial niobium bar to obtain an ingot; 2, turning processing; 3, extruding to obtain an extruded bar billet; 4, after turning processing, carrying out first-stage annealing treatment; 5, rotating forging to obtain a rotating forged bar billet; 6, carrying out second-stage annealing treatment, and then carrying out surface sanding to obtain a sanded bar billet; 7, drawing a roller die to obtain a rough wire billet; 8, after surface treatment, carrying out fixed die drawing and shaping to obtain a half finished wire product; and 9, after surface treatment, carrying out straightening to obtain the high-purity niobium for the nuclear fuels with the diameter being 1.5-3.0mm and the straightness being smaller than 3mm / m. The method is less in thermal treatment fire times, little in thermal processing and high in rate of finished product. According to the high-purity niobium wire prepared by the invention, the size, surface inspection and components of the high-purity niobium wire all accord with the requirement on a nuclear material, and the high-purity niobium wire can be directly used for preparing uranium-niobium alloy for the nuclear fuels.

Description

technical field [0001] The invention belongs to the technical field of material processing, and in particular relates to a method for preparing high-purity niobium wire for nuclear fuel by using general industrial niobium bars as raw materials. Background technique [0002] Metal niobium is a rare metal with a high melting point. It is not only a good structural material, but also a special functional material, which can be widely used in metallurgy, chemical industry, aerospace and atomic energy and other fields. Niobium has a low neutron capture cross section, good thermal conductivity, and high thermal strength, making it a very suitable material for atomic energy reactors. With the development of science and technology and the progress of society in our country, the development and utilization value of nuclear industry, especially nuclear energy, has become more and more significant, and metal niobium has also been more widely used in the field of atomic energy. Metal u...

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Problems solved by technology

This type of traditional preparation process has the following disadvantages: if forging is used to open the blank, ordinary forging hammer die forging cannot guarantee the surface quality during the forging process, and it is easy to form a large number of forging defects such as inclusions and folding. In addition, if a precision forging machine is used, the cost is higher In addition, the surface is also easy to form a large number of folds and other defects. The above two forging blanking methods are likely to cause uneven surface and core structures of the forged billet. Based on the heredity of material processing, it will directly affect the subsequent wire drawing. ; The forged rod is rolled to obtain thin niobium rods. During the rolling process, rolling defects such as ears are easy to form. If they are not eliminated in time, defects such as folding will be formed and directly affect the subsequent wire drawing; traditional niobium and In the preparation process of niobium alloy wire, after repeated vacuum annealing, on the one hand, the content of gas impurity elements such as O will increase excessively, on the other hand, the process will be lengthened and the processing cost will be increased. Considering the safety of nuclear power, nuclear grade The content of impurity elements in the material needs to be strictly controlled, and the risk of unnecessary increase in impurity content should be avoided as far as possible. Therefore, it is not advisable to produce nuclear niobium wires by multiple firing processes; Surface treatment is only simple treatment such as pickling and cleaning agent washing, which cannot remove surface oxides and impurities. Such treatments will directly affect the surface quality and impurity content of the finished wire.

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