Tungsten bar has the characteristics of high melting point, high density, low vapor pressure and low thermal expansion properties. It also offers good thermal conductivity, sufficient electrical resistance, and high modulus of elasticity. It can be sintered or swaged. And it is available in thicknesses of 0.1~15mm and size up to 450x1000mm.
Forging and Annealing Process of Pure Tungsten Bar
The sintered pure tungsten bar was forged by different average forging ratio and forging method, then was annealed with different annealing process. The microstructure and physical and mechanical properties of the samples were determined by metallurgical microscope, hardness tester and density tester, etc. The results showed as follows:
1. Both the hardness and the density of pure tungsten bar have been improved remarkably by forging, but the tungsten bar could be cracked once the average forging ratio is too big.
2. Compared with the tungsten bar forged with smaller average forging ratio and one heating and one end, the tungsten bar forged with bigger average forging ratio and one heating and two ends has finer grain structure and bigger density. And it needs higher annealing temperature and longer annealing time to recrystallize completely during annealing.
3. The tungsten bar prepared by this kind of process has higher hardness before annealing and at the beginning of annealing. With the recrystallization being completed, the hardness of the two kinds of tungsten bars decreases gradually and there is no obvious difference between them.
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