1、Designation: F2094/F2094M 11F2094/F2094M 13Standard Specification forSilicon Nitride Bearing Balls1This standard is issued under the fixed designation F2094/F2094M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year of last r
2、evision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers the establishment of the basic quality, physical/mechanical property, and test requirements forsil
3、icon nitride balls Classes I, II, and III to be used for ball bearings and specialty ball applications.1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be
4、 used independently of the other. Combining values from thetwo systems may result in non-conformance with the standard.2. Referenced Documents2.1 Order of Precedence:2.1.1 In the event of a conflict between the testtext of this document and the references herein, the text of this document takesprece
5、dence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has beenobtained.2.2 ASTM Standards:2C1161 Test Method for Flexural Strength of Advanced Ceramics at Ambient TemperatureC1421 Test Methods for Determination of Fracture Toughness of Advan
6、ced Ceramics at Ambient Temperature2.3 ANSI Standard:ANSI/ASQC Z1.4 Sampling Procedures and Tables for Inspection by Attributes32.4 ABMA Standards:STD 10 Metal Balls42.5 ASME Standard:B 46.1 Surface Texture (Surface Roughness, Waviness, and Lay)52.6 ISO Standards:4505 HardmetalsMetallographic Determ
7、ination of Porosity and Uncombined Carbon32.7 JIS Standards:R 1601 Testing Method for Flexural Strength (Modulus of Rupture) of High Performance Ceramics6R 1607 Testing Method for Fracture Toughness of High Performance Ceramics62.8 CEN Standards:EN 843-1 Advanced Technical CeramicsMonolithic Ceramic
8、sMechanical Properties at Room Temperature, Part 1.Determination of Flexural Strength7ENV 843-5 Advanced Technical CeramicsMonolithic CeramicsMechanical Properties at Room Temperature, Part 5,Statistical Analysis71 This specification is under the jurisdiction of ASTM Committee F34 on Rolling Element
9、 Bearings and is the direct responsibility of Subcommittee F34.01 on RollingElement.Current edition approved May 1, 2011Oct. 1, 2013. Published May 2011October 2013. Originally approved in 2001. Last previous edition approved in 20082011 asF2094/F2094M 08.F2094/F2094M11. DOI: 10.1520/F2094_F2094M-11
10、.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Application for copies should be addressed to the American
11、 National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.4 Application for copies should be addressed to the American Bearing Manufacturers Association, 1200 19th Street NW, Suite 300, Washington, DC 20036-2401.5 Application for copies should be address
12、ed to the American Society of Mechanical Engineers (ASME), ASME International Headquarters, Three Park Ave., New York,NY 10016-5990, http:/www.asme.org.6 Application for copies should be addressed to the Japanese Standards Organization (JSA), 4-1-24 Akasaka Minato-Ku, Tokyo, 107-8440, Japan, http:/w
13、ww.jsa.or.jp.7 Application for copies should be addressed to the British Standards Institute (BSI), 389 Chiswick High Rd., London W4 4AL, U.K., http:/www.bsi-.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been ma
14、de to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Cop
15、yright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 ball diameter variation (Vdws)variation, Vdws, nball diameter variation is the difference between the largest andsmall
16、est diameter measured on the same ball.3.1.2 ball gage (S)gage, S, nprescribed small amount by which the lot mean diameter should differ from nominal diameter,this amount being one of an established series of amounts. A ball gage, in combination with the ball grade and nominal balldiameter, should b
17、e considered as the most exact ball size specification to be used by a customer for ordering purposes.3.1.3 ball gage deviation (S)deviation, S, ndifference between the lot mean diameter and the sum of the nominaldiameter and the ball gage.3.1.4 ball grade (G)grade, G, nspecific combination of dimen
18、sional form and surface roughness tolerances. A ball gradeis designated by a grade number followed by the letter “C” indicating Silicon Nitride Ceramic.3.1.5 blank lotlot, nsingle group of same-sized ball blanks processed together from one material lot through densification.3.1.6 ceramic second phas
19、e, nadditive phases, for example, yttria and alumina, which appear darker or lighter than the siliconnitride matrix, but are not highly reflective in nature.3.1.7 deviation from spherical form (Rw)form, Rw, ngreatest radial distance in any radial plane between a spherecircumscribed around the ball s
20、urface and any point on the ball surface.3.1.8 finish lotlot, nsingle group of same-sized balls (which may be derived from multiple blank lots of the same materiallot) processed together through finishing.3.1.9 inclusion, nany discrete imhomogeneity in the microstructure that is not intended to be i
21、ncluded in the material.3.1.9.1 DiscussionInclusions typically consist of foreign material as a result of unintended external powder contamination and resulting reactionproduct after sintering.3.1.10 lot diameter variation (Vdwl)variation, Vdwl, ndifference between the mean diameter of the largest b
22、all and that ofthe smallest ball in the lot.3.1.11 lot mean diameter (Dwml)diameter, Dwml, narithmetic mean of the mean diameter of the largest ball and that of thesmallest ball in the lot.3.1.12 material lotlot, nsingle process lot of silicon nitride raw powder received from a material supplier.3.1
23、.13 mean diameter of a ball (Dwm)ball, Dwm, narithmetic mean of the largest and the smallest actual single diametersof the ball.3.1.14 metallic phase, nmaterial phase that is highly reflective when viewed by light microscopy3.1.15 nominal diameter (Dw)diameter, Dw, nsize ordered that is the basis to
24、 which the nominal diameter tolerances apply.The nominal diameter is specified in inches or millimeters (decimal form).3.1.16 nominal diameter tolerancetolerance, nmaximum allowable deviation from true specified nominal diameter for theindicated grade.3.1.17 single diameter of a ball (Dws)ball, Dws,
25、 nthe distance between two parallel planes tangent to the surface of the ball.3.1.18 surface roughness (Ra)Ra, nsurface irregularities with relative small spacings, which usually include irregularitiesresulting from the method of manufacture being used or other influences, or both.3.1.19 unit contai
26、nercontainer, ncontainer identified as containing balls from the same manufacture lot of the samecomposition, grade, and nominal diameter, and within the allowable diameter variation per unit container for the specified grade.4. Classification4.1 Silicon nitride materials for bearing and specialty b
27、all applications are specified according to the following material classes(see Appendix X1 for typical current applications):4.1.1 Class IHighest grade of material in terms of properties and microstructure. Suitable for use in the most demandingapplications. This group adds high reliability and dura
28、bility for extreme performance requirements.4.1.2 Class IIGeneral class of material for most bearing and specialty ball applications. This group addresses the concerns ofball defects as is relative to fatigue life, levels of torque, and noise.4.1.3 Class IIILower grade of material for low duty appli
29、cations only. This group of applications primarily takes advantageof silicon nitride material properties. For example: Light weight, chemical inertness, lubricant life extension due to dissimilaritywith race materials, etc.and so forth.F2094/F2094M 1325. Ordering Information5.1 Acquisition documents
30、 should specify the following:5.1.1 Title, number, and date of this specification.5.1.2 Class, grade, and size (see 4.1, 8.6, and 8.7).6. Material6.1 Unless otherwise specified, physical and mechanical property requirements will apply to all material classes.6.2 Silicon nitride balls should be produ
31、ced from either silicon nitride powder having the compositional limits listed in Table1 or from silicon metal powder, which after nitridation complies with the compositional limits listed in Table 1.6.3 Composition is measured in weight percent. Testing shall be carried out by a facility qualified a
32、nd approved by the supplier.Specific equipment, tests, and/or methods are subject to agreement between suppliers and their customers.6.4 Compounds may be added to promote densification and enhance product performance and quality.6.5 Iron oxides may be added to promote densification with the total ir
33、on content for the final product not to exceed 1.0 weight%.6.6 Precautions should be taken to minimize contamination by foreign materials during all stages of processing up to andincluding densification.6.7 A residual content of up to 2 % tungsten carbide from powder processing is allowable.6.8 Fina
34、l composition shall meet and be reported according to the specification of the individual supplier.6.9 Notification will be made upon process changes.6.10 Specific requirements such as specific material grade designation, physical/mechanical property requirements (forexample, density) or quality or
35、testing requirements shall be established by specific application. The special requirements shall bein addition to the general requirements established in this specification.6.11 Typical mechanical properties will fall within the range listed in Table 2. Individual requirements may have tighter rang
36、es.The vendor shall certify that the silicon nitride material supplied has physical and mechanical properties within the range givenin Table 2. In the case of properties indicated by (+), the provision of the data is not mandatory.7. Physical Properties7.1 The following physical properties shall be
37、measured, at a minimum, on each material lot.7.1.1 Average values for room temperature rupture strength (bend strength/modulus of rupture) for a minimum of 20 individualdeterminations shall exceed the minimum values given in Table 3. Either 3-point or 4-point test methods may be used for flexuralstr
38、ength, which should be measured in accordance with Test Method C1161 (size B), CEN 843-5, or JIS R 1601. Weibull modulusfor each test series shall also exceed the minimum permitted values given in Table 3. If a sample set of specimens for a materiallot does not meet the Weibull modulus requirement i
39、n Table 3, then a second sample set may be tested to establish conformance.7.1.2 The hardness (HV) shall be determined by the Vickers method (see Annex A1) using a load of at least 5 kg but notexceeding 20 kg. Fracture resistance shall be measured by either an indentation technique (see AnnexA1) or
40、by a standard fracturetoughness test method. Average values for hardness and fracture resistance shall exceed the minimum of values for the specifiedmaterial class given in Table 4.7.1.3 Microstructure constituents visible at magnification in the range 100 to 200 shall not exceed the maximum values
41、givenin Table 5 for the specified material class.7.1.4 The number of ceramic metallic or mixed inclusions observed in transverse sections shall not exceed the limits given inTable 6.7.1.5 Macrostructure variation visible at 1 on a polished section is not permissible.7.1.6 Density variation from the
42、mean value of a sample of at least 10 pieces taken from a batch of components manufacturedunder the same conditions shall not exceed the values for 3 times the standard deviation (3 sigma) given in Table 7, accordingTABLE 1 Compositional Limits for Starting Silicon NitridePowders or Silicon Powder C
43、onverted to Silicon NitrideAConstituents Limits (wt %)Silicon nitride 97.0 min.Free silicon 0.3 max.Carbon 0.3 maxIron 0.5 max.A Other impurities or elements such as sodium, potassium, chlorine, etc. individu-ally shall not exceed 0.02 wt % max.F2094/F2094M 133to the volume of the component after an
44、y finishing operations and the specified material class. Density variation testing will applyto all lots of material for the initial 50 lots. If consistent results are achieved, the testing will be optional.8. Inspection and Verification8.1 The intent of this section is to list potential defects and
45、 methods of inspection of finished balls. As the spectrum ofapplications for silicon nitride balls is very broad, this is not intended to define requirements, but to highlight these points. Thetype of defects, methods of inspection, and limits should be agreed upon by the customer and vendor to meet
46、 the specificrequirements for a given application.8.2 Unless otherwise specified, all dimensional and form inspections shall be performed under the following conditions:8.2.1 TemperatureRoom ambient 20 to 25C 68 to 77F.8.2.2 Humidity50 % relative, maximum.8.3 Unless otherwise required, product shall
47、 be capable of passing acceptance inspection in accordance withANSI/ASQC Z1.4as specified in Table 8.TABLE 2 Typical Mechanical PropertiesAProperties Minimum MaximumDensity, g/cc lb/ft3 3.0 187 3.4 212Elastic modulus, GPa ksi 270 39 150 330 47 850Poissons ratio 0.23 0.29Thermal conductivity, W/m-K B
48、tu/h-ft-F 20C (room temp.)20 11.5 38 21.9Specific heat, J/kg-K Btu/Ibm-F 650 0.167 800 0.191Coefficient of thermal expansion, 10-6/C(room temp. to 500C)2.3 3.4+ Resistivity, Ohm-m 1010 1016+ Compressive strength, MPa ksi 3000 435A Special material data should be obtained from individual suppliers.TA
49、BLE 3 Minimum Values for Mean Flexural Strength andWeibull ModulusMaterial ClassUnit I II IIITransverse-rupturestrengthA3 point 3,40(3,30)MPa 900 920 800 825 600 625Weibullmodulus12 9 7Transverse-rupturestrengthA4-point 4,40(4,30)MPa 765 805 660 705 485 530Weibullmodulus12 9 7A The Flexural strength equivalents are based on Weibull volume or surfacescaling using the value of m for each cell and are rounded to the nearest 5 MPa.n,L = denotes the f
