| 摘要 |
PURPOSE:To decrease the incidence of accidents wherein pressed green compacts are fractured and cracked in the stage of pressing W powder by mixing two kinds of W powders of specific grain sizes and pressing the mixture. CONSTITUTION:After green compacts of W powder is produced in the stage of producing W filaments, the green compacts are made into W filaments by sintering, rotary forging and drawing. In the stage of producing the green compacts of the W powder in this case, two kinds of W powders of large and small grain sizes, like 3.5mu and 4.5mu grain sizes measured with a Fischer Sub Sieve Sizer are mixed at 10:90-90:10 ratio and further, K2O which is a dopant, as well as Al2O3, SiO2, etc. are mixed therewith at proper ratios, and the mixture is pressed in dies, whereby the green compacts are produced. If the mixture of 2.0-6.0mu the W powders are used in the above-mentioned way, the ratios at which fractures, cracks, etc. arise in the molded green compacts are markedly reduced, and the decrease in the yield of the products in the stage of W filaments is prevented. |
