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 PRODUCT LIST |
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Ceramic Bearing Character |
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 Compare Ceramic materials and steel materials
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Items |
Unit |
Bearing steel |
Stainless steel |
Si3N4
Silicon nitride |
Zro2 Zirconia |
SiC Silicon carbide |
Al2O3Alumina |
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Technical Property |
Density D |
g/cm3 |
7.85 |
7.90 |
3.20 ～ 3.30 |
6.00 |
3.10 |
3.95 |
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Coeff.of linear expansion α |
10-6/K |
10.0 |
11.0 |
3.2 |
10.5 |
4.5 |
8.5 |
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Young's
modulus E |
GPa |
208 |
200 |
300～ 320 |
210 |
≥350 |
380 |
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Poisson's ratio |
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0.30 |
0.30 |
0.26 |
0.30 |
0.20 |
0.22 |
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Hardness
Hv H RC |
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700 62 |
≤300 |
1300～ 1600
75 ～80 |
1000～1200
70 |
≥2500
85～90 |
1600～1800/ 80 |
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Bending strength
σ RT |
MPa |
2400 |
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600～1000 |
950 ～ 1200 |
≥450 |
300～ 500 |
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Fracture toughness KⅠ C |
MPam1/2 |
25 |
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5.0 ～ 7.0 |
8.0 ～ 10.0 |
3.0 ～ 4.0 |
3.0～4.0 |
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Thermal conductivity λ |
W/mk |
30 ～ 40 |
15 |
35 |
2 ～ 3 |
150 |
30 |
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Special electrical resistance |
Ωmm2/m |
0.1～ 1 |
0.75 |
1018 |
1015 |
101-3 |
1018 |
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Working property |
Max working temperature |
℃ |
120 |
300 |
800 |
800 |
1400 |
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Corrosion resistance |
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poor |
poor |
good |
good |
good |
good |
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Stress cycles (50% failed) |
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107 |
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107～ 109 |
105 |
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Nonlubrication friction |
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large |
large |
little |
little |
little |
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Magnetism |
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magnetic |
magnetic |
non-magnetic |
non-magnetic |
non-magnetic |
Non-magnetic |
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Centrifugal force |
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very large |
very large |
little |
large |
little |
middle |
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Operate temp. increasing |
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high |
high |
low |
- |
low |
- |
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Size stability |
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unstable |
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stable |
unstable |
stable |
unstable |
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Conductivity |
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conductor |
conductor |
insulator |
insulator |
conductor |
insulator |
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Rolling contact failure form |
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spalling |
- |
spalling |
crush |
crush |
crush |
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