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|
materials used in metrology
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Black granite |
 |
Used for all precision measuring instruments. |
 |
Absolute black granite |
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Used on request for small or medium high precision instruments |
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Blue Lanhelin |
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Used for big granite benches and plates, comes from France. |
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CELITH - composite granite |
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Especially used for machine tools bases for its innovative and technical properties. |
 |
SI-SIC silicon carbide |
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Extremely suitable, due to its unique properties like hardness, elasticity modulus, lenght expantion, for sliding guides manufacturing, also with the use of air bearings system. |
COMPARATIVE TABLE
| |
Black granite |
Absolute black |
Blue
Lanhelin |
Celith |
SiSic |
Cast iron |
| Density (Kg/dm3) |
2.85 |
3.0 |
2.7 |
2.3 |
3.1 |
7.2 |
| Porosity (%) |
0.09 |
0.15 |
0.35 |
- |
0.0 |
- |
| Elasticity modulus (Gpa) |
60 - 105 |
90 - 103 |
44 - 58 |
30 - 40 |
370 |
- |
| Compression resistance (Mpa) |
244 |
270 |
188 |
120 - 150 |
850 |
500 |
| Tensile strenght (Mpa) |
24 |
25 |
21.5 |
10 - 15 |
- |
150 - 250 |
| Thermal expantion coeff. |
6.5 x 10-6
m/m° C |
5.9 x 10-6
m/m° C |
7.4 x 10-6
m/m° C |
10-15 x 10-6
m/m° C |
3.7 x 10-6
m/m° C |
10-13 x 10-6
m/m° C |
| Thermal conductivity (W/m°K) |
2 |
2.5 |
2 |
1-3 |
160 |
50 |
| Hardness Vikers (Mpa) |
8140 |
8000 |
8800 |
- |
25000 |
- |
| Origine |
Afrika |
India |
France |
France |
Germany |
- |
| Colour |
Dark grey |
Black |
Grey |
Natural |
Grey |
- |
|
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