Raw hard metal materials

OUR MATERIALS - TUNGSTEN CARBIDE

We are a Precision Engineering Company, we machine parts from Tungsten Carbide, if you would like us to provide a quote from your technical drawing please click here: contact us

The rest of this page provides general purpose information on Tungsten Carbide.

We use Tungsten Carbide everyday in a variety of products, for use in a number of different applications throughout many industries. It is an incredibly versatile and useful material due to its unique properties which are outlined below:

General

When evaluating or finding equivalents of Tungsten Carbide grades the important criteria is to specify two of three factors. Binder content, hardness or grain size. In straight matrix materials any two of these will match the third. A 15% binder with hardness of 88.0 RA would have to be fine grain material whereas with a hardness of 86.0 RA would need a very coarse grade to achieve it. Specifying cobalt binder only can be a dangerous game. Take control of each situation and ensure you know what you are using and why so that consistency of specification can be obtained from whatever source. We can achieve hardness differential on 15% cobalt: purely by varying the grain size, that would need a spread of 11% cobalt over same gain size materials. I.e. We can manufacture 15% material with a hardness of a 6% or 18% grade just by using sub micron or coarse grains !!

The Tungsten Carbide properties chart below shows basic data for each grade manufactured. All specifications are designed and engineered for a purpose and rigid controls are kept throughout production processes to ensure adherence to grade engineering.

Quality control properties such as hardness, density, and minimum transverse rupture strength were determined from tests made on each batch of powder before it is used in the manufacturing process. Other properties such as Young's modulus of Elasticity , Poisson's ratio , Coefficient of Thermal Expansion, Thermal Conductivity and Electrical Conductivity are used by engineers for design calculations. Properties such as compressive strength, grain size and abrasion resistance give the designer additional information about the suitability of the grade for the part being designed.

Binder

The binder in most grades of Tungsten Carbide is cobalt. The other binder used is nickel. The binder is added as a percentage by weight varying from 3% to 30%. The amount of binder used is a very important factor in determining the properties of each grade. As a rule of thumb the lower the cobalt content the harder the material will become. However variation in grain size and additives can upset this rule.

Density

Determined by comparison of mass with volume and usually stated in g/cm3.

Grain Size

The majority of grades we manufacture are made with standard size grains varying between 1 and 3 microns in size. Using larger grains of 2 - 6 microns will greatly increase the strength and toughness of the material because the larger grains interlock better. The trade off is that larger grain materials do not offer as much resistance to wear as finer grain sized materials. Sub micron materials that vary between 0.4 and 1.0 micron grain size are harder than standard grain materials with the same cobalt content. The sub micron grains are much more uniform in size and hence give improved hardness as well as increased carbide strength. However, as specs show the transverse rupture strength is perhaps 20% improved on 15% sub micron compared to 15% fine grain material but this can give a false impression as sub micron carbide is not as resistant to impact and may chip more easily.

Rockwell Hardness

The hardness of Tungsten Carbide 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.

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.

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. This high compressive strength makes it possible to compress carbon at one million P.S.I. from man made diamonds.

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.

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.

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.

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.

Thermal Conductivity

Tungsten Carbide conducts heat much more rapidly than tool steel. Thermal conductivity rates go down as the binder content goes up.

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 but the most conductive tungsten carbide grade we manufacture would only make 10.7% of copper.

Electrical Resistivity

Determined by voltage drop for known current over known cross section area and test piece length.

Detailed Grades

Please see charts below showing more detailed values for specific Tungsten Carbide grades.

Grade Binder Grain Hardness Density TRS CS Mod of E Poisson's Electrical Thermal Electrical Coeff thermal expansion
  % Av RA g/cm³ psi psi x10 psi Ratio Conductivity Conductivity resistivity 20-400 C 20-800 C
                  % of copper W/mK µohmcm 10e-6/K 10e-6/K
CD20 3.0 1.3 91.8-92.8 15.1-15.3 180,000 660,000 94.2 0.22 5.0 80 20 4.7 4.9
CD24X 5.0 1.3 91.5-92.5 14.9-15.1 240,000 680,000 93.0 0.22 5.0 80 20 4.7 4.9
CD30 6.0 1.3 90.5-92.0 14.8-15.0 260,000 690,000 91.8 0.22 7.8 85 19 4.9 5.3
CD35F 9.0 1.0 90.2-91.2 14.5-14.7 300,000 700,000 84.2 0.22 7.8 95 19 5.3 5.5
CD35 9.0 2.0 89.8-90.8 14.5-14.7 275,000 682,000 84.0 0.23 9.2 90 19 5.2 5,4
CD36 10.0 2.0 89.5-90.5 14.4-14.6 280,000 675,000 82.4 0.22 8.4 95 19 5.4 5.6
CD337 11.0 4.0 88.0-89.0 14.3-14.5 420,000 650,000 82.2 0.26 10.7 100 18 5.5 5.7
CD38 12.0 1.5 88.8-89.8 14.2-14.4 320,000 650,000 79.5 0.23 8.6 95 18 5.7 5.9
CD18 12.0 1.3 89.0-90.0 14.2-14.4 340,000 660,000 79.5 0.23 8.6 85 18 5.7 5.9
CD40 13.0 1.5 88.5-89.5 14.1-14.3 340,000 639,000 78.0 0.24 8.8 90 18 5.7 5.9
CD45 14.0 1.5 88.0-89.0 14.0-14.2 360,000 600,000 76.7 0.24 8.8 85 17 5.8 6
CD50 15.0 1.5 87.5-88.5 13.9-14.1 375,000 639,000 75.2 0.24 9.0 100 17 6.0 6.2
CD53 16.0 1.5 87,0-88.0 13.8-14.0 375,000 600,000 74.0 0.24 9.2 90 17 6.1 6.3
CD55 17.0 2.0 86.0-87.0 13.7-13.9 375,000 554,000 72.6 0.24 9.2 90 17 6.2 6.4
CD60 20.0 4.0 83.0-84.5 13.4-13.6 380,000 483,000 68.9 0.26 10.1 90 16 6.5 6.9
CD70 25.0 4.0 81.5-83.0 13.2-13.4 370,000 454,000 64.5 0.26 8.7 90 16 7 7.2
                           
CD630 6.0 0.8 92.0-93.5 14.8-15.0 325,000 880,000   0.22   80 20 5.2 5.5
CD636 10.0 0.8 90.5-91.5 14.4-14.6 410,000 775,000   0.22   85 19 5.4 5.6
CD640 13.0 0.8 90.5-91.5 14.0-14.2 440,000 685,000   0.22   90 18 5.7 5.9
CD650 15,0 0.8 89.0-90.5 13.9-14.1 500,000 650,000   0.23   90 17 6.2 6.4
CD750 15.0 0.6 90.5-91.5 13.9-14.1 600,000 725,000   0.23   90 17 6.3 6.5
                           
CD3WJ 3.0 0.8 93.6-94.5 15.2-15.4 160,000 550,000   0.21   80 20    
CDRMR11 11.0 5.0 86.0-87.5 14.3-14.5 410,000 640,000   0.23   100 18    
CDRMR15 15.0 5.0 85.0-86.5 13.9-14.1 370,000 530,000   0.23   100 17    
Grade Binder Grain Hardness Density TRS CS Mod of E Poisson's Electrical Thermal Electrical Coeff thermal expansion
  % Av RA g/cm³ N/mm² N/mm² x10 psi Ratio Conductivity Conductivity resistivity 20-400 C 20-800 C
          minimum       % of copper W/m K µohmcm 10e-6/K 10e-6/K
CD20 3.0 1.3 91.8-92.8 15.1-15.3 1250 4600 94.2 0.22 5.0 80 20 4.7 4.9
CD24 5.0 1.3 91.5-92.5 14.9-15.1 1650 4700 93.0 0.22 5.0 80 20 4.7 4.9
CD30 6.0 1.3 90.5-92.0 14.8-15.0 1800 4750 91.8 0.22 7.8 85 19 4.9 5.3
CD35F 9.0 1.0 90.2-91.2 14.5-14.7 2075 4900 84.2 0.22 7.8 95 19 5.3 5.5
CD35 9.0 2.0 89.8-90.8 14.5-14.7 1900 4750 84.0 0.23 9.2 90 19 5.2 5.4
CD36 10.0 2.0 89.5-90.5 14.4-14.6 1950 4700 82.4 0.22 8.4 95 19 5.4 5.6
CD337 11.0 4.0 88.0-89.0 14.3-14.5 2900 4500 82.2 0.26 10.7 100 18 5.5 5.7
CD38 12.0 1.5 88.8-89.8 14.2-14.4 2200 4500 79.5 0.23 8.6 95 18 5.7 5.9
CD18 12.0 1.3 89.0-90.0 14.2-14.4 2350 4600 79.5 0.23 8.6 85 18 5.7 5.9
CD40 13.0 1.5 88.5-89.5 14.1-14.3 2350 4500 78.0 0.24 8.8 90 18 5.7 5.9
CD45 14.0 1.5 88.0-89.0 14.0-14.2 2500 4250 76.7 0.24 8.8 85 17 5.8 6
CD50 15.0 1.5 87.5-88.5 13.9-14.1 2600 4500 75.2 0.24 9.0 100 17 6.0 6.2
CD53 16.0 1.5 87.0-88.0 13.8-14.0 2600 4200 74.0 0.24 9.2 90 17 6.1 6.3
CD55 17.0 2.0 86.0-87.0 13.7-13.9 2600 3950 72.6 0.24 9.2 90 17 6.2 6.4
CD60 20.0 4.0 83.0-84.5 13.4-13.6 2600 3400 68.9 0.26 10.1 90 16 6.5 6.9
CD70 25.0 4.0 81.5-83.0 13.2-13.4 2550 3200 64.5 0.26 8.7 90 16 7 7.2
                           
CD630 6.0 0.8 92.0-93.5 14.8-15.0 2600 6000   0.22   80 20 5.2 5.5
CD636 10.0 0.8 90.5-91.5 14.4-14.6 2850 5350   0.22   85 19 5.4 5.6
CD640 13.0 0.8 90.5-91.5 14.0-14.2 3050 4800   0.22   90 18 5.7 5.9
CD650 15.0 0.8 89.0-90.5 13.9-14.1 3150 4500   0.23   90 17 6.2 6.4
CD750 15.0 0.8 90.5-91.5 13.9-14.1 3850 5000   0.23   90 17 6.3 6.5
                           
CD3WJ 3.0 0.8 93.6-94.5 15.2-15.4 1150 3800   0.21   80 20    
CDRMR11 11.0 5.0 86.0-87.5 14.3-14.5 2050 4450   0.23   100 18    
CDRMR15 15.0 5.0 85.0-86.5 13.9-14.1 2550 3700   0.23   100 17    

 

 

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