Abstract: The grain size of vanadium is related to the degree of deformation and to the temperature of the subsequent annealing process. After purifying with cerium in an arc furnace with a nonconsumable tungsten electrode in an atmosphere of pure helium, the initial vanadium contained 0.07% oxygen, 0.21% carbon, 0.01% nitrogen, and about 0.2% metallic impurities. The vanadium was cold-rolled without breaking to a high degree of deformation. The metal was cold-rolled with a 50% reduction and annealed in vacuum for 1 hour in order to break up the large- grain structure. The average grain size was 63 mu after this treatment. Samples were cold-rolled with reductions of 5, 10. 15, 25, 50, 75, and 90% without an intermediate anneal. The hardness of the initial vanadium is 120 kg/ mm/sup 2/. and increases with increasing reduction (136 kg/mm/sup 2/ at 5% reduction, 156 kg/mm/sup 2/ at 25% reduction, and 165 kg/mm/sup 2/ at 50 to 95% reduction). The reduced samples were annealed in vacuum at 750 to 1300 deg C for one hour. The initial recrystallization temperature of vanadium decreases with increasing degree of deformation. It is 900 deg C at 5% reduction, 800 deg C at 50% reduction. and 775more » deg C at 95% reduction. Recrystallization results in complete removal of the cold-rolled structure. The average grain size is about 20 mu . No increase in grain size is observed on annealing the cold-rolled samples at temperatures up to 1050 deg C, but a sharp increase in grain size is noted at 1100 deg C with the samples which had been reduced by 10%, and at 1200 deg C for the 15% reduced samples. The average grain size increases from 20 mu to 40 mu at an annealing temperature of 1200 deg C for the samples with 25% reduction. The optinium treatment of vanadium. which gives a fine-grained structure and good mechanical properties, is cold-rolling with a reduction of 50 to 955, and an anneal at a temperature of 850 to 1050 deg C in an inert atmosphere. (TTT)« less
Publication Year: 1962
Publication Date: 1962-07-21
Language: en
Type: article
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