Dental Bearings

Miniature Ball Bearings

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Bearing Material

Standard material for rings and balls is a vacuum degassed high carbon chromium steel allowing for high efficiency, low torque, low noise level and long bearing life. For bearings requiring anti-corrosion or heat-resistance properties, martensitic stainless steel is used.

CHEMICAL COMPOSITION OF BEARING MATERIALS


Chemical Composition of Bearing Material
Material High Carbon Chromium Steel Stainless Steel
Symbol Gcr15 SUS440C
KS440
AISI304
AISI316
Chemical Composition
%
C 0.95 ˜ 1.10 0.95 ˜ 1.20 0.60 ˜ 0.75 ≤0.08 ≤0.08
Si 0.15 ˜ 0.35 ≤1.00 ≤1.00 ≤0.75 ≤0.75
Mn ≤0.50 ≤1.00 ≤1.00 ≤2.0 ≤2.0
P ≤0.025 ≤0.04 ≤0.030 ≤0.45 ≤0.45
S ≤0.025 ≤0.03 ≤0.020 ≤0.03 ≤0.03
Cr 1.30 ˜ 1.60 16.00 ˜ 18.00 11.50 ˜ 13.50 18.00 ˜20.00 16.00 ˜ 18.00
Mo ≤0.08 ≤0.75 ≤0.30   2.0 ˜ 3.0
Ni 10.5 ≤0.01
N ≤0.10 ≤0.10
Hardness HRC 60-64 HRC58-62 HRC58-62 HRB92 HRB95
EQUIVALENT SAE52100, 100Cr6, SUJ2 AISI440C,
X105CrMo17
X65Cr13,KS440
(ACD34)
SUS304
X5CrNi1810
SUS316
X5CrNiMo17-12-2

Bearing Material Selection

Non-Corrosive environment:
Normal use, low to moderately high speed, all loads, low to medium temperature (less than 120C constant and/or 150C intermittent).
Use chrome steel bearings. Check grease capabilities if in the higher temperature or higher speed range. Nylon or polyamide cage not desirable for 110C or more.
High speed use, low to medium temperature (less than 120C constant and/or 150C intermittent).
Use chrome steel bearings with high speed grease. Consider polyamide cage and/or ceramic balls for higher speeds. Consider high temperature grease if in the higher temperature range.
High temperature use (121C to 250C constant and/or 151C to 300C intermittent).
Use 440 stainless steel bearings with stainless steel cage. Check grease speed rating if in the higher speed range.
High speed & high temperature use (121C to 250C constant and/or 151C to 300C intermittent).
Use 440 stainless steel bearings with stainless steel cage and ceramic balls.
Very high temperature use (up to 1200C).
Use unlubricated full complement (no cage) all-ceramic bearings. The maximum working temperature for Zirconia (ZRO2) is approx 1100C and for Silicon Nitride (Si3N4) it is 1200C


Moderately corrosive environment:
Depending on the amount of moisture or liquid present, it may be necessary to use a water resistant or chemical resistant lubricant for corrosive environments.
Normal use, low to high speed, all loads, low to medium temperature (less than 120C constant and/or 150C intermittent).
Use corrosion resistant 440 stainless steel bearings..
Low load and speed use, low to medium temperature (up to 100C constant).
Use corrosion resistant 440 stainless steel bearings or plastic (acetal) corrosion resistant bearings. Beware lower rolling accuracy of plastic bearings. Also check load/speed ratings for plastic bearings.
High speed use, low to medium temperature (less than 120C constant and/or 150C intermittent).
Use corrosion resistant 440 stainless steel bearings. Consider polyamide cage and/or ceramic balls for higher speeds.
High temperature use (up to 250C constant), very low load/speed.
Use corrosion resistant 440 stainless steel bearings with high temp grease or unlubricated plastic PTFE/PEEK bearings. Beware lower rolling accuracy of plastic bearings. Check load/speed ratings for plastic bearings.
High temperature use (up to 250C constant), medium to high load/speed.
Use corrosion resistant 440 stainless steel bearings with high temp grease

Highly corrosive environment (more highly concentrated acids & alkalis, saltwater):
Highly corrosive environment, very low load/speed.
Use unlubricated corrosion resistant plastic or all-ceramic bearings or 316 stainless steel bearings with a chemical or saltwater resistant lubricant. Beware lower rolling accuracy of plastic and 316 stainless steel bearings. Consider more corrosion resistant bearing materials such as PEEK, PTFE or HDPE for acids/alkalis.
Highly corrosive environment, moderate to high load, low speed.
Use unlubricated all-ceramic bearings with PEEK or PTFE cage or full complement type (no cage).


Non magnetic environment:
Very low load/speed.
Use plastic, 316 stainless steel or full ceramic bearings. Beware lower rolling accuracy of plastic and 316 stainless steel bearings.
Moderate to high load, low speed.
Use full ceramic bearings with nylon or PTFE cage or full complement type (no cage).


Food environment:
Depending on the location of the bearings, some type of USDA approved lubricant will be required in the bearings. H1 grade lubricants are used where there is a possibility of incidental contact with food and H2 where there is no possibility of contact.
Normal use, low to high speed, all loads, low to medium temperature (less than 120C constant and/or 150C intermittent).
Use corrosion resistant 440 stainless steel bearings with food grease.
Low load and speed use, low to medium temperature (up to 100C constant).
Use corrosion resistant 440 stainless steel bearings with food grease or plastic (acetal) bearings with no lubrication. Beware lower rolling accuracy of plastic bearings. Also check load/speed ratings for plastic bearings.
High speed use, low to medium temperature (less than 120C constant and/or 150C intermittent).
Use corrosion resistant 440 stainless steel bearings with food grease. Consider polyamide cage and/or ceramic balls for higher speeds.
High temperature use (up to 250C constant), very low load/speed.
Use corrosion resistant 440 stainless steel bearings with high temp food grease or unlubricated plastic PTFE/PEEK bearings. Beware lower rolling accuracy of plastic bearings. Check load/speed ratings for plastic bearings.
High temperature use (up to 250C constant), medium to high load/speed.
Use corrosion resistant 440 stainless steel bearings with high temp food grease


Vacuum environment:
Normal use, low speed, all loads, low to medium temperature (less than 120C constant and/or 150C intermittent).
Use 440 stainless steel bearings with stainless steel cage, either unlubricated or with vacuum grease or with MOS treatment. Consider hybrid bearings (stainless steel rings & ceramic balls) or all-ceramic bearings.
High speed use, low to medium temperature (up to 150C constant).
Use 440 stainless steel bearings with stainless steel cage, ceramic balls and vacuum grease.
High temperature use (up to 250C constant), medium to high load/speed.
Use 440 stainless steel bearings with stainless steel cage and high temp vacuum grease. Consider ceramic balls or unlubricated all-ceramic bearings
Very high temperature use (up to 1200C).
Use unlubricated full complement (no cage) all-ceramic bearings. The maximum working temperature for Zirconia (ZRO2) is approx 1100C and for Silicon Nitride (Si3N4) it is 1200C


Bearing Material -Bearing Closures - Lubricants - Noise - Internal Clearance - Retainer(cage) - Tolerance

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