Tungsten Carbide Material

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Tungsten Carbide Material

What is tungsten carbide?

Tungsten carbide is a compound of tungsten and carbide that creates an extremely dense crystalline structure called hexagonal crystals. It is press-formed by a technique known as sintering. The sintered and manufactured carbide has compressive strength, extremely high thermal hardness, as called Solid carbide, with wear resistance, corrosion resistance and impact resistance.

Solid carbide refers to metal carbides. Fine grains of tungsten carbide are combined or cemented with cobalt. Powder metallurgy technology is cleverly used to produce solid carbide.

Tungsten carbide is often called carbide because of its extraordinarily high hardness relative to other metals. There are currently more than 20 different grades of tungsten carbide with varying grain size, hardness, tensile strength and melting point characteristics. Tungsten carbide is comparable to diamond as the hardest material available. It is used in major industries around the world and is widely used in machining applications requiring excellent wear resistance or impact resistance, such as in the manufacture of cutting and wear tools, molds and wear-resistant machine parts.

Factors affecting the performance of tungsten carbide

Adhesive

The adhesive for most tungsten carbides is cobalt, which contains a number of rare elements. The amount of the adhesive is the most important factor in determining the performance of each grade.

Cobalt content

The lower the cobalt content, the harder the material, according to experimental results. With the addition of cobalt, it becomes harder and more impact resistant. With less cobalt added, the more resistant it is to abrasion, whereas the parts are prone to breakage when hit.

Grain size

The micron grains we use, which range in size from 0.2 to 0.6μm, are harder than standard grains materials with the same cobalt content. The more uniform size of the micron grains increases the hardness and carbide strength. Smaller grains have better milling resistance; larger grains have better anti-impact performance. Ultra fine grains of tungsten carbide are exceptionally hard, and ultra coarse grains are best suited for extreme abrasion and impingement applications.
Minimum Transverse Fracture Strength (TRS), TRS is a measure of the strength of tungsten carbide that increases with cobalt content.

Density

Density is determined by the ratio of mass to volume and indicated as g/cm3. Higher densities indicate better protection against abrasion and tougher tungsten carbide. They can withstand longer machining time and are better polished. Neither the cobalt percentage nor the grain size alone determines the performance of a grade, but by varying the grain size and cobalt percentage, solid carbide can be made stronger.

Mixed Materials

Tungsten carbide conducts heat much faster than tool steel, but the thermal conductivity decreases as the binder content increases.

Manufacturing Technology

Tungsten carbide has high corrosion resistance and is an extraordinarily stable material that does not oxidize in atmospheric air.

Production of CNC machining tools from tungsten carbide

Tungsten carbide is one of the few materials that can be considered for machining jobs in industry, with excellent machinability and thermal properties and is extremely hard with a melting point in excess of 1800°C. End mills made from cemented tungsten carbide are highly wear-resistant and can withstand higher temperatures than ordinary high-speed steel (HSS) tools. Its hardness is close to diamond and it is mainly used to produce workpieces that are resistant to high pressure and high temperature.

Carbide cutting is typically used to machine carbon steel and stainless steel workpieces. Compared with steel workpieces, carbide cutting tools can provide a better finish on the parts because of their high sharpness, high temperature resistance, and increased machining speed. Tungsten carbide end mills make the drilling, grinding and milling of metals more efficient and economical.

Type of Solid Carbide Material	WC %	CO %	Average Grain Size/ µm	GPA T.R.S. N/mm²	Desity ISO 3369 [g/cm³]	Hardness Vickers HV30	Coating	Working Material’s Hardness
A	90	10	0.6	3600	14.5	1600	X-CEED	HRC 55
B	86.65	13	0.4	3900	13.9	1700	X-CEED	HRC 60
C	89.8	9	0.2	4000	14.3	2000	NACO	HRC 68