The processing accuracy of tantalum niobium products can be controlled within the standard tolerance range by the method of repeated rotary forging. The feed speed of the rotary forging machine and the number of repeated forging of the finished product determine the dimensional accuracy of the finished product. The slower the feed speed, the more forging times, the smaller the ellipticity and standard deviation of the diameter, and the greater the vice versa. The machining method of rotary forging + rolling can realize the machining of large-diameter thin-wall thickness to small-diameter thick-wall pipe. The wall thickness tolerance of ordinary pipe can be controlled within ±10%, and the wall thickness tolerance of high-precision pipe can be controlled within ±8% by the method of point and line surface repair and rolling mill trig principle. It is found that the number of distinguishable classes of the outer diameter of the niobium zirconium wire is = 5, and the measuring system is acceptable.
Compared with the traditional drawing and cutting machining methods, the rotary forging of tantalum niobium bar has better surface finish, higher material utilization rate and efficiency. The main stress state of the deformation area is three-way compressive stress, and the main deformation state is three-way compression extension, which is conducive to improving the plasticity of the forging blank. As the equipment adopts manual feeding method, it cannot guarantee the uniform speed of the bar feeding, which results in large fluctuations in the size of the finished product, and poor precision control of the size of the finished product. By properly adjusting the thickness of the equipment gasket and adopting multi-pass rotary forging through minitab data statistics, it is found that the diameter tolerance of the finished pipe bar rotary forging can be controlled within the standard deviation range. The length tolerance can be controlled to + 6.35mm. The wall thickness of the ordinary tantalum niobium pipe can be controlled within ±10% by the method of rotary forging + rolling, and the processing accuracy of the high-precision pipe can be controlled within ±8% by manual debugging of the principle of point, line, surface repair and trig.
For pipes with large outer diameter and small wall thickness, the wall can be increased by spinning forging and then finished product rolling [3]. The f19 × 1.2mm pipes rolled by two or three rollers can be spun and rolled to produce f10 × 1.5mm niobium zirconium pipes. The spinning forging process is adopted for 5 passes and the diameter reduction is 1 mm. When the outer diameter is f12 mm, the measured wall thickness is 1.7~1.8 mm. After the subsequent straightening, f7mm mandrel three-roll finished rolling is adopted, and the wall thickness tolerance of the finished product can reach ±7%. In order to ensure a certain speed ratio between the speed V1 of the slide and the speed of the roll V2, the length and height of the connecting rod can be adjusted by adjusting the upper and lower positions of the slider in the guide groove of the rocker.
