The methods of preparing tungsten carbide by tungsten powder
by Lee Dora noneTungsten carbide is largely used for high-speed cutting tools, furnace structural materials, jet engine parts, metal ceramic materials, resistance heating elements and so on. For the manufacture of cutting tools, wear parts, copper, cobalt, bismuth and other metal melting crucible, wear-resisting semiconductor thin film. As superhard cutting tool materials, wear-resistant materials, it can form a solid solution with various carbides. It also can be used as additives of NbC-C and TaC-C ternary carbides, not only reduced the sintering temperature, but also maintaining excellent performance, can be used as aerospace materials.
From metal powder supplier we known that tungsten carbide was produced in two ways, one is
used tungsten metal powder and charcoal as raw material, dry mixed the average
particle diameter of 3 ~ 5μm tungsten powder and the same amount of substance
carbon black with a ball mill, after thorough mixing, compression molding and
put into a graphite plate, then heated to 1400 ~
Another
is WO3 hydrogenation obtained tungsten powder (average particle size is 3 ~ 5μm). Then pressure molding the
tungsten powder and carbon black at the equimolar mixture (dry mixing in a ball
mill for 10h) under a pressure of about 1t/cm2. Put the press molding material
into the graphite disk or block crucible, heated with the graphite resistance
furnace or induction furnace in a hydrogen gas stream to 1400 ~
Tungsten dust can cause peribronchitis, peribronchiolar, blocking bronchiolitis and atrophic emphysema. Tungsten carbide may cause lung lymphoid tissue cell proliferative response, and gradually emergence sclerosis. Vascular wall was thickening and homogenization. People exposure to tungsten carbide dust in work will cause gastrointestinal disorders, kidney suffered irritation, upper respiratory tract appeared catarrhal inflammation. The maximum allowable concentration of tungsten carbide is 6mg/m3.
Staff should use the satisfactory gas mask, dust-proof clothing, gloves, glasses. Prevent dust leakage in all stages of production. Workers should do pre-employment physical examination, periodic inspection once every year. When the upper respiratory tract appears obvious symptoms must temporarily transfer work, do not contact with tungsten. If show up lung hardening or respiratory function disorders should be removed from the work. Tungsten carbide should be stored in a cool, dry depot, pay attention to check whether the packaging containers in good condition during transport, prevent rain and sunlight exposure.
Article Source:http://www.mhcmp.com
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Created on Dec 31st 1969 18:00. Viewed 0 times.