Tungsten carbide
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| Tungsten carbide | |
|---|---|
| |
| General | |
| Molecular formula | WC |
| Molar mass | 195.86 g/mol |
| Appearance | grey-black solid |
| CAS number | [12070-09-9] |
| Properties | |
| Density and phase | 15.8 g/cm3, solid |
| Solubility in water | Insoluble |
| Melting point | 2870 °C, 5198 °F (3143K) |
| Boiling point | 6000°C, 10832 °F (6273K) |
| Thermal conductivity | 84.02 W/(m K) |
| Tensile strength | 0.3448 GPa |
| Mohs hardness | 9 |
| Structure | |
| Coordination geometry | ? |
| Crystal structure | Hexagonal |
| Thermodynamic data | |
| Standard enthalpy of formation ΔfH°solid | ? kJ/mol |
| Standard molar entropy S°solid | ? J.K−1.mol−1 |
| Hazards | |
| EU classification | not listed |
| NFPA 704 | |
| Supplementary data page | |
| Structure and properties | n, εr, etc. |
| Thermodynamic data | Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Other anions | Tungsten boride Tungsten nitride |
| Other cations | Molybdenum carbide Titanium carbide Silicon carbide |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) [Chemical infoboxInfobox disclaimer and references] | |
Tungsten carbide, WC, or W2C, is a chemical compound containing tungsten and carbon, similar to titanium carbide. Its extreme hardness makes it useful in the manufacture of cutting tools, abrasives and bearings, as a cheaper alternative to diamond. Tungsten carbide is also used as a scratch-resistant material for jewelry including watch bands and wedding rings.
Uses in machine tools
Carbide cutting surfaces are often useful when machining tough materials, such as carbon steel or stainless steel, as well as in situations where other tools would wear away, such as high-quantity production runs. Sometimes, carbide will leave a better finish on the part, and allow faster machining. Carbide tools can also withstand higher temperatures than standard high speed steel tools.Machining with carbide can be difficult, as carbide is more brittle than other tool materials, making it susceptible to chipping and breaking. To offset this, many manufacturers sell carbide inserts and matching insert holders. With this setup, the small carbide insert is held in place by a larger tool made of a tougher material (usually steel). This gives the benefit of using carbide without the high cost of making the entire tool out of carbide. Also, the inserts can be changed without losing much accuracy, allowing the machinist to simply swap out a broken insert without re-zeroing the machine. Most modern face mills use carbide inserts, as well as some lathe tools and endmills.
To increase the life of carbide tools, they are sometimes coated. Two such coatings are TiN (titanium nitride) and TiC (titanium carbide). Most coatings generally increase a tool's hardness and or lubricity. A coating allows the cutting edge of a tool to cleanly pass through the material without having the material gall (stick) to it. The coating also helps to decrease the temperature associated with the cutting process and increase the life of the tool.
External links
- [International Chemical Safety Card 1320]
- [NIOSH Pocket Guide to Chemical Hazards]
- [Memsnet: Properties of tungsten carbide]
- For a full list of external links to MSDSs, spectroscopic data, commercial chemicals suppliers etc. for this compound, see [Chemical sources].
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