ASTM F2730/F2730M-08

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Designation: F2730/F2730M – 08
Standard Specification for
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Silicon Nitride Cylindrical Bearing Rollers
ThisstandardisissuedunderthefixeddesignationF2730/F2730M;thenumberimmediatelyfollowingthedesignationindicatestheyear
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
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1. Scope 2.5 CEN Standards:
EN 843-1 Advanced Technical Ceramics—Monolithic
1.1 This specification covers the establishment of the basic
Ceramics—Mechanical Properties at Room Temperature,
quality, physical/mechanical property, and test requirements
Part 1, Determination of Flexural Strength
for silicon nitride rollers Classes I, II, and III to be used for
ENV 843-5 Advanced Technical Ceramics—Monolithic
cylindrical roller bearings.
Ceramics—Mechanical Properties at Room Temperature,
1.2 The values stated in either SI units or inch-pound units
Part 5, Statistical Analysis
are to be regarded separately as standard. The values stated in
each system are not exact equivalents; therefore, each system
3. Terminology
must be used independently of the other. Combining values
3.1 Definitions of Terms Specific to This Standard:
from the two systems may result in nonconformance with the
3.1.1 chips—break-outs of material greater in extent than
specification.
0.25 mm typically at the corner chamfers or the junction of the
2. Referenced Documents chamfers with the cylindrical surface or end face.
3.1.2 cracks—irregular, narrow breaks in the surface of the
2.1 Order of Precedence:
roller typically having a visible width of less than 0.002 mm.
2.1.1 In the event of a conflict between the text of this
Most cracks are formed after densification but occasionally
document and the references herein, the text of this document
may be present as material faults. Some cracks may not be
takes precedence. Nothing in this document, however, super-
visiblewithnormalwhitelightmicroscopyandmayonlyshow
sedes applicable laws and regulations unless a specific exemp-
up under ultraviolet light after processing with a suitable
tion has been obtained.
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fluorescent penetrant.
2.2 ASTM Standards:
3.1.3 cuts—short linear or circumferential grooves having a
C1161 Test Method for Flexural Strength of Advanced
width of more than 0.005 mm and a length of more than 0.20
Ceramics at Ambient Temperature
mm. Cuts are normally assessed under roller surface appear-
C1421 Test Methods for Determination of Fracture Tough-
ance but large and/or numerous cuts can be considered defects.
ness of Advanced Ceramics at Ambient Temperature
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3.1.4 flats—flat bands running along the length of the
2.3 ASME Standard:
cylindrical part of the roller, usually caused by a stop in
B 46.1 Surface Texture (Surface Roughness, Waviness, and
rotation of the roller during machining. Flats can also be
Lay)
4 formed at one end only by incorrect approach into a machining
2.4 JIS Standards:
operation.
R 1601 Testing Method for Flexural Strength (Modulus of
3.1.5 grooves—shallow machining marks having a width of
Rupture) of High Performance Ceramics
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more than 0.005 mm extending more than ⁄4 of the circum-
R 1607 Testing Method for Fracture Toughness of High
ference on the cylindrical surface or having a length of more
Performance Ceramics
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than ⁄4 of the roller diameter on the end faces.
3.1.6 inclusions—isolated areas of ceramic second phases
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ThisspecificationisunderthejurisdictionofASTMCommitteeF34onRolling
or metallic appearing phases. Inclusions are often the result of
Element Bearings and is the direct responsibility of Subcommittee F34.01 on
contamination by foreign material during the roller blank
Rolling Element.
manufacturing process.
Current edition approved Nov. 15, 2008. Published January 2009. DOI: 10.1520/
F2730_F2730M-08.
3.1.7 material lot—single process lot of silicon nitride raw
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
powder received from a material supplier.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3.1.8 mean roller diameter—one half the sum of the largest
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. andsmallestofindividualdiametersmeasuredinasingleradial
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Available from American Society of Mechanical Engineers (ASME), ASME
plane.
International Headquarters, Three Park Ave., New York, NY 10016-5990, http://
www.asme.org.
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Available from Japanese Standards Organization (JSA), 4-1-24 Akasaka Available from European Committee for Standardization (CEN), 36 rue de
Minato-Ku, Tokyo, 107-8440, Japan, http://www.jsa.or.jp. Stassart, B-1050, Brussels, Belgium, http://www.cenorm.be.
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