Abrasion Resistance
Carbide's exceptional resistance to abrasion is its most important property. In abrasive applications, carbides can outlast some wear-resistant steel alloys by a factor of 100 to 1.Compressive Strength
Compressive strength is measured by compressing a right cylinder test piece between two tungsten carbide blocks held in line by an outer sleeve assembly. The CS of tungsten carbide is higher than for virtually all metals and alloys. Some grades of carbide with cobalt binder perform flawlessly under ultra-high compression and have been used very successfully in pressure applications at up to one million psi.
Corrosion Resistance
Since carbides are generally chemically inert (considering binding material as a factor), they can be used successfully in many chemical and corrosive environments. However, the cobalt binders are vulnerable to certain concentrated acids. It may also be subject to galvanic corrosion, for example, when assembled with copper-bearing materials in the presence of fluids, which act as electrolytes. Such applications are extremely rare, but when they arise it is again the cobalt binder that is vulnerable. Under highly corrosive conditions, the cobalt binder can be replaced with nickel. However, this increase in corrosion resistance is accompanied by a detrimental effect on the mechanical properties. Many corrosive fluids contain abrasives, and tungsten carbides combined resistance to corrosion and abrasion is often the governing factor in choosing this material.
Deflection Resistance
Cemented carbides have a high modulus of elasticity that provides minimum deflection when exposed to bending forces. In fact, the modulus of elasticity is three times that of steel.
Electrical Conductivity
Electrical conductivity of tungsten carbide is determined by comparing it to that of copper. Thereby the copper standard being 100% . Generally the conductivity of tungsten carbide increases as the cobalt content increases.
Electrical Resistivity
Determined by voltage drop for known current over known cross section area and test piece length
High Temperature Wear Resistance
At 1,000°F, carbides still maintain over 90% hardness. Certain grades can even retain significant strength at 2,000°F (higher at intermittent temperatures).
Impact Strength
This measures the resistance of tungsten carbide to shock loading by a drop weight impact test. This is a more reliable indication of toughness than TRS readings.
Low Temperature Wear Resistance
Even at cryogenic temperatures as low as -453°F, carbides retain good wear resistance and offer a relatively low coefficient of friction where lubricants cannot be used.
Mean Coefficient of Thermal Expansion
This indicates the amount of expansion which might be expected when heat is applied to the material. The expansion rate increases with temperature increase. The more binder present the higher the expansion rate. Tungsten carbide is about 1/3 to 1/2 that of tool steel.
Minimum Transverse Rupture Strength (TRS)
TRS is a measure of the strength of tungsten carbide. Tensile strength is not used on tungsten carbide because it is too brittle and accurate readings cannot be obtained. As a rule of thumb the tensile strength of tungsten carbide is approx. half of the transverse rupture strength.Transverse rupture strength values are determined by the amount of force needed to break standard test pieces under the same test conditions.
Poisson's Ratio
Poisson's ratio may most easily be described by thinking of a marshmallow held between two flat plates. As the plates are pushed together the marshmallow is compressed and squashes out. All metals, even tungsten carbide, squash out at least a very small amount. The ratio varies only slightly with the amount of cobalt binder.
Rockwell Hardness
The hardness of grades is determined by using the Rockwell hardness tester. A pointed diamond indenter is forced into the carbide. The depth of the hole is a measure of the hardness. The Rockwell "A" scale is used for tungsten carbide. Rockwell "C" readings are only shown on the data sheet so that tooling people can compare values of carbide against tool steel. The "A" scale is used on tungsten carbide because the lower indenting force of 60 KGs is less likely to damage the diamond than the 150 KGs force used on the "C" scale.
Specific gravity
Specific gravities range from 11.5 to a little over 15, depending on the composition. The lower end of the scale is associated with a high titanium-carbide content, and the upper end of the scale with a very low binder content. To put this in context, this is 1.3 to 1.9 times heavier than mild steel.
Thermal Conductivity
Tungsten carbide conducts heat much more rapidly than tool steel. Thermal conductivity rates go down as the binder content goes up.
Torsional Strength
With a torsion modulus twice that of high-speed steel, carbide is the preferred material for rotating applications.
Toughness
Carbide grades with higher binder contents have excellent resistance to impact.
Young's Modulus of Elasticity
Young's Modulus of Elasticity is an indication of the elasticity or bendability of tungsten carbide. Bendability increases with the increase in binder.Tungsten carbide is generally regarded as a non-ductile material, with a Young’s modulus about 2-3 times that of steel. However, this very high stiffness is advantageous in solid carbide tooling, boring bars, precision spindles and other components where rigidity must be maintained under heavy loads.