Table of Common Bearing Material Characteristics
Technical data Unit SUJ2 SUS440C Si3N4 ZrO2
Density (ρ) g/cm3 7.8 7.9 3.2 6
Coefficient of expansion 10-6℃ 11.5 17 3 10.5
Poisson ratio (μ) 　 0.3 0.3 0.26 0.3
Εmodulus of elastcity Gps 208 200 320 210
HV Haedness 　 800 700 1700 1300
Indetation strength Mpa 　 　 3600 2000
Flexural strength(σ) Mpa 2400 2600 900 1000
Impact strength(Kc) Nm/cm2 20 25 7 11
Specific resistivity(Ω) mm2/m 1 0.7 1018 1015
Thermal conductivity(λ) W/mk 30-40 15 3.5 2.5
Specific heat j/KgK 450 450 800 400
MAX temperature ℃ 120 150 1000 800
Anti-cortossion 　 None Week Strong Stong
Fatigue failure conditions 　 Peel off Peel off Peel off Peeling  breakage/
Magnetism 　 Yes Yes None None
Dimension stability 　 Not good Not good Good Good
Insulation 　 Not good Not good Good Good
Engineering plastic bearing materials
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Material Unit HDPE PP POM PA6 PA66 PVDF PPS PTFE PEEK PI
Long term working temperature ℃ 90 100 110 100 100 150 230 240 260 300
Density (ρ) - 0.96 0.91 1.42 1.13 1.14 1.7 1.35 2.2 1.3 1.35
Tensile strength at yieid Mpa 25 30 70 85 80 50 75 25 95 　
Tensile strength at break Mpa 35 　 　 　 　 4.6 　 　 　 116
Ball indentation headn Mpa 50 80 170 160 170 80 190 30 　 　
Sliding friction coefficient - 0.29 0.3 0.34 0.38-0.45 0.35-0.45 0.3 　 0.08-0.1 0.3-0.38 0.3-0.38
Impact characteristics KJ/m2 None None None None None None 50 None None 75
Siding wear μ/km 　 11 1.6 0.23 0.9 　 　 21 　 0.3-0.38
Vicat softening temp ℃ 130 165 175 220 260 172 280 327 343 　
Glass transition temperature ℃ -95 -18 -60 -60 -72 -18 -90 -20 -143 　
MAX  temperature ℃ 90 140 150 160 170 150 260 260 300 350
Linear expansion coefficient 10-5/K 13-15 17 10 8 8 13 5 12 5 4.9
Dielectric constant 106HZ 2.4 2.3 3.7 3.7-7 3.6-5 8 　 2.1 3.3 3.1
Volume resistance Ω.cm ＞1015 ＞1014 ＞1014 ＞1013 ＞1012 ＞1014 ＞1013 ＞1016 ＞1016 ＞1017
Natural weathering tolerance - Intolerance Intolerance Intolerance Intolerance Intolerance Tolerable Intolerance Tolerable Intolerance Tolerable