Tungsten Carbide Washington DC

Tungsten carbide is a chemical compound that contains carbon and tungsten and is similar to titanium carbide. In most cases, tungsten carbide is simply referred to as carbide. Tungsten carbide alloys are prepared by reacting carbon and tungsten at a temperature of between 1400-2000ºC. The other method involves using a patented fluid bed process to mix Hydrogen and tungsten elements at a temperature of not less than 900ºC. Other methods are by the use of vapor deposition, which are still under investigation.

Tungsten carbide has melting point of 2870ºC and a low electrical resistivity of between 1.7-2.2 10¯ 7 ohm-m. For practical applications, it is alloyed with cobalt, a softer metal. This ceramic material is highly resistant to wear and its hard property makes it ideal for use in wear parts of machines or surfaces subject to corrosion, abrasion or high temperatures. The material has low ductility at high temperatures. It is also known for its high strength properties. As shown above, it exhibits good thermal and electrical conductivity. Adding 6-30% titanium carbide increases the above properties.

Carbide tools for cutting are used in machines that are intended to get into contact with carbon steel and stainless steel. Most of the time tungsten carbide is used as the first material to run through a surface, leaving a finer finish for other machines. In situations where high exposures to high temperatures are to be expected, tungsten carbide is employed since it can withstand extremely high temperatures that would melt industry strong steel or other metals. In such situations, the tungsten carbide is referred to as cemented carbide. During manufacture, cobalt is melted and once in the liquid stage, the cobalt combined with tungsten carbide alloys or particles, which act as the aggregate while the cobalt, forms the metal matrix composite. This process is called sintering or hot isostatic pressing. Addition of the naturally ductile cobalt metal goes a long way to ensuring that the tungsten carbide exhibits the characteristic brittle behavior. This process raises the durability and toughness f the final product. Machining of carbide is a difficult undertaking since the carbide tends to be brittle compared to other tool materials. As a result, it is prone to breaking and chipping. To counteract this problem, manufacturers have resorted to selling carbide inserts or simply carbide matching insert holders. With this configuration, the carbide insert is held firmly in place by the larger tool that is made of less brittle material. This combination is usually between tungsten carbide and steel. This arrangement has the benefit of incorporating carbide use without having to worry about the high cost of manufacturing the entire tool purely of tungsten carbide. Most modern face mills are using carbide inserts as well as some lather tools and end mills. To increase their lifespan, the tools are coated with Tin, Tic or TiAIN. Most of these coatings have enabled the tool to be harder and/or have more lubricity. Use of a coating also has the advantage of lowering the temperature associated with the cutting and it increases the life of the tool under use.

Talley Jewelry, Inc.

301-645-5144
3035 Festival Way
Waldorf, MD
www.talleyjewelry.com