GB1308679A - Method of manufacturing rotary anodes for use in x-ray tubes - Google Patents

Abstract

1308679 Making anodes; welding by pressure PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 5 Nov 1970 [8 Nov 1969] 52715/70 Headings B3A and B3R A rotary anode for an X-ray tube is made by heating in a non-oxidizing atmosphere an anode portion 6, Fig. 1, consisting mainly of tungsten and a support portion 1 mainly of molybdenum, and subjecting the portions to an impact which joins them together at their contacting machines surfaces, the resulting assembly of increased diameter then being stress-relieved by annealing. Sintered tungsten starting material may be used from which a wafer is sawn and then rolled to increase its density. A circular disc 6 is then cut which is ground and/or polished on at least one side. Molybdenum for the support 1 contains at least one constituent capable of raising the recrystallization temperature, e.g. titanium, zirconium or carbon, or of reducing the recystallization rate, e.g. potassium silicate. A known alloy may be used having the following percentages by weight: Ti-0À55 to 0À40, Zr-0À12 to 0À06 and C-0À03 to 0À01. The portions 1, 6 were assembled in a double box 3, 4 of molybdenum and heated to 1650‹ C. in a nitrogen or hydrogen atmosphere for impact between a hammer and anvil. Layers 10, 11, Fig. 2, produced by the boxes are removed by grinding or polishing. Stress-relief annealing is carried out in a non-oxidizing atmosphere, e.g. at 1000‹ C. for 1À5 hours. The assembly may be cold-formed at 1000‹ C. into a dish, Fig. 4 (not shown), and drilled centrally. Starting material for the support may be formed by sintering a mixture of Mo powder and 0À001-0À005% potassium silicate. The material may be compacted by a forging or flattening operation. Both starting materials may be porous, matching of the deformability being by adjustment of the sintering. The support may be stiffened by silicon carbide needles or a grid of tungsten wire.