Tungsten carbide manufacture involves a complex sequence of operation, unique to this industry, in which almost every factor is critical to success.
The original, and still the basic, product consists of fine tungsten carbide particles-the hard and abrasion-resistant constituent-bonded with tough, comparatively soft, metallic cobalt. Tungsten carbide can be supplemented or substituted by other hard constituents, such as the carbides or nitrides of other refractory metal, typically titanium, tantalum, niobium, chromium, vanadium, molybdenum or hafnium, independently or in combination, whilst the cobalt may similarly be alloyed with, or substituted by, nickel, nickel-molybdenum or similar metallic elements.
The sintered product has often been compared to bricks or mortar, the comparison being true to the extent that the mortar (cobalt) is liquid during the final sintering and set solidly on being cooled from the sintering temperature. However, carbide is very much harder than brick and cobalt substantially tougher than mortar.
Typical stages of manufacture are:
Production of tungsten metal powder (tungsten ore refine to tungsten metal). Preparation of tungsten carbide (the progression from tungsten powder to tungsten monocarbide WC_generally termed tungsten carbide)
Preparation of alloyed and other carbides (mix many kinds of metal according to certain proportion)
Admixture of cobalt to Produce grade powders
Addition of Pressing lubricant.
Pressing
Pre-sintering
Sharpening
Final sintering (usually use vacuum sintering)
Hot isostatic Pressing(HIP)
The Product is rarely used as sintered, but is generally ground, polished ,shot-blasted, plated or coated to create a more accurate form or a still harder and more wear-resistant surface.
