ВПЛИВ ТРИВАЛОСТІ ДІЇ ЗОВНІШНЬОГО ОДНООСЬОВОГО ТИСКУ НА ГУСТИНУ ТВЕРДИХ СПЛАВІВ ВК20 ТА ВН20 ПРИ ЇХ КІНЦЕВОМУ СПІКАННІ У ВАКУУМІ
The influence of the uniaxial pressure on the density of previously sintered wolfram carbide cylindrical specimens from VK20 and VN20 hard alloys with cobalt and nickel ligaments, respectively, during sintering in vacuum at temperatures of 1400 and 1460 ° C was investigated. The difference between t...
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| Date: | 2019 |
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| Main Authors: | , , , |
| Format: | Article |
| Language: | Ukrainian |
| Published: |
Институт сверхтвердых материалов им. В. Н. Бакуля Национальной академии наук Украины
2019
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| Subjects: | |
| Online Access: | http://altis-ism.org.ua/index.php/ALTIS/article/view/54 |
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| Journal Title: | Tooling materials science |
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Tooling materials science| Summary: | The influence of the uniaxial pressure on the density of previously sintered wolfram carbide cylindrical specimens from VK20 and VN20 hard alloys with cobalt and nickel ligaments, respectively, during sintering in vacuum at temperatures of 1400 and 1460 ° C was investigated. The difference between the above method of producing alloys and the widely used method of hot pressing lies in the fact that during sintering of the carbide blank under pressure, a graphite mold is not used, which leads to excessive carburization of the blank. The parameters of sintering of these alloys under the action of external uniaxial pressure are given: compression stress (from 0 to 0.7 MPa) during final sintering, rubber ejection temperature, as well as temperature of preliminary, re-preliminary and final sintering of alloys in a methane-hydrogen environment. Graphs were plotted for the density of alloys previously sintered in different variants as a function of the duration of the compression stress during final sintering in vacuum at different temperatures. The maximum density values of the VK20 and VN20 alloys, which were 13.77 and 13.75 g/cm3, respectively, were obtained by sintering at a temperature of 1460 °C and an external compressive stress of 0.6 MPa (for 30 minutes). Increase the specified voltage to the maximum (0.7 MPa) at a sintering temperature of 1400 °C in 30 minutes the action of the load did not lead to an increase in the density of the alloys to the maximum value. |
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