1、Designation: F799 11Standard Specification forCobalt-28Chromium-6Molybdenum Alloy Forgings forSurgical Implants (UNS R31537, R31538, R31539)1This standard is issued under the fixed designation F799; the number immediately following the designation indicates the year of originaladoption or, in the ca
2、se of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers requirements of cobalt-28chromium-6molybdenum alloy (UNS R31537
3、, R31538,R31539) high-strength forgings for the manufacture of surgicalimplants. The properties specified in this document specificallyapply to finished or semifinished parts that receive no subse-quent thermomechanical processing.1.2 Wrought material to be used as forging stock in themanufacture of
4、 forgings conforming to this specification,typically hot worked and unannealed with a surface finishsuitable for forging, shall be fabricated and supplied inaccordance with F1537.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated
5、ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.2. Referenced Documents2.1 ASTM Standards:2E8 Test Methods for Tension Testing of Metallic MaterialsE18 Test
6、 Methods for Rockwell Hardness of Metallic Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE112 Test Methods for Determining Average Grain SizeE165 Practice for Liquid Penetrant Examination for GeneralIndustryE930 Test Methods for Estimatin
7、g the Largest Grain Ob-served in a Metallographic Section (ALA Grain Size)F75 Specification for Cobalt-28 Chromium-6 MolybdenumAlloy Castings and Casting Alloy for Surgical Implants(UNS R30075)F601 Practice for Fluorescent Penetrant Inspection of Me-tallic Surgical ImplantsF981 Practice for Assessme
8、nt of Compatibility of Biomate-rials for Surgical Implants with Respect to Effect ofMaterials on Muscle and BoneF1537 Specification for Wrought Cobalt-28Chromium-6MolybdenumAlloys for Surgical Implants (UNS R31537,UNS R31538, and UNS R31539)ASTM SI 10 American National Standard for Use of theInterna
9、tional System of Units (SI): The Modern MetricSystem2.2 ISO Standards:3ISO 6892 Metallic MaterialsTensile Testing at AmbientTemperatureISO 9001 Quality Management SystemsRequirements2.3 American Society for Quality Standard:4ASQ C1 Specification of General Requirements for a Qual-ity Program3. Termi
10、nology3.1 Definitions of Terms Specific to This Standard:3.1.1 lot, nthe total number of forgings produced from thesame heat of starting material under the same conditions atessentially the same time.4. Ordering Information4.1 Inquiries and orders for material under this specificationshall include t
11、he following information:4.1.1 Quantity, number of pieces4.1.2 ASTM designation, date of issue, and alloy number,4.1.3 Condition,4.1.4 Mechanical properties,4.1.5 Finish,4.1.6 Applicable dimensions or drawing number,4.1.7 Special tests, if any, and1This specification is under the jurisdiction of AST
12、M Committee F04 onMedical and Surgical Materials and Devices and is the direct responsibility ofSubcommittee F04.12 on Metallurgical Materials.Current edition approved June 1, 2011. Published June 2011. Originallyapproved in 1982. Last previous edition approved in 2006 as F799 06. DOI:10.1520/F0799-
13、11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANS
14、I), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.4Available from American Society for Quality (ASQ), 600 N. Plankinton Ave.,Milwaukee, WI 53203, http:/www.asq.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Driv
15、e, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.1.8 Other requirements.5. Materials and Manufacture5.1 Materials for forgings shall be bar, rod, or wire fabri-cated in accordance with Specification F1537.5.2 The material shall be forged by hammering, pressing,rolling, extruding, or
16、 upsetting, and shall be processed, ifpractical, so as to cause metal flow during the hot-workingoperation to be in the most favorable direction for resistingstresses encountered in service, as may be indicated to thesupplier by the purchaser.5.3 Forgings shall be free of splits, scale, cracks, flaw
17、s, andother imperfections not consistent with good commercialpractice (see Note 1). Offset or mismatch allowance, dependentupon part size and configuration, shall be within standardforging tolerances.5.4 Optional indentification marks, including the purchas-ers logo, material designation, heat code
18、number, and impres-sion number, may be placed upon each forging, the method andlocation of which shall be as specified by the purchaser.NOTE 1Compliance to these requirements may be verified by TestMethod E165 or Practice F601 or other suitable methods.6. Chemical Requirements6.1 The cobalt-28chromi
19、um-6molybdenum alloy forgingsshall conform to the chemical requirements prescribed inTable 1 of Specification F1537. The supplier shall not shipmaterial that is outside the limits specified in Table 1 ofSpecification F1537 for the applicable alloys. SpecificationF1537 contains three alloys:Alloy 1 L
20、ow Carbon (UNS R31537)Alloy 2 High Carbon (UNS R31538)Alloy 3 Dispersion Strengthened (UNS R31539)7. Mechanical Requirements7.1 Tensile Properties:7.1.1 Tensile properties shall be determined in accordancewith Test Methods E8.7.1.2 The mechanical properties of test specimens preparedfrom finished or
21、 semifinished parts shall conform to therequirements in Table 1.7.1.3 Tension test specimens shall be produced from fin-ished or semifinished parts or from material having the sameprocess history as that which exists in the final forging. Tensionspecimens may have a ground finish on the reduced sect
22、ion andmay be taken in a direction parallel to the long axis of thefinished or semifinished part.7.1.4 A minimum of two tension test specimens shall betested. Should either of the two specimens not meet thespecified requirements, two additional specimens shall betested and both must pass.7.1.5 If an
23、y fracture takes place outside the middle half ofthe gauge length or in a punched or scribed gauge mark withinthe reduced section, the elongation value obtained may not berepresentative of the material. In acceptance testing, if theelongation so measured meets the minimum requirementsspecified, no f
24、urther testing is required, but if the elongation isless than the minimum requirements, discard the test and retest.7.1.6 In some instances, mechanical test pieces may not beobtainable directly from forged parts due to their configurationor small size. Instead of mechanical testing, these parts shal
25、lexhibit hardness of HRC 35 to 45 when tested in accordancewith Test Methods E18.7.2 HardnessForgings conforming to this specificationshall have a minimum Rockwell C hardness of 35 HRC. Thehardness determination shall be performed in accordance withTest Methods E18.8. Dimensions and Permissable Vari
26、ations8.1 Units of Measure:8.1.1 SelectionThis specification requires that the pur-chaser selects the units (SI or inch-pound) to be used forproduct certification. In the absence of a stated selection ofunits on the purchase order, this selection may be expressed bythe purchaser in several alternate
27、 forms listed in order ofprecedence.8.1.1.1 If the purchaser and supplier have a history of usingspecific units, these units shall continue to be certified untilexpressly changed by the purchaser.8.1.1.2 In the absence of historic precedence, if the unitsused to define the product on the purchasers
28、PO, specification,and engineering drawing are consistent, these units shall beused by the supplier for product certification8.1.1.3 If the purchasers selection of units is unclear, theunits of measure shall be agreed upon between the purchaserand supplier.8.1.2 Conversion of UnitsIf the suppliers te
29、st equipmentdoes not report in the selected units, the test equipment unitsmay be converted to the selected units for certification pur-poses. Accurate arithmetic conversion and proper use ofsignificant digits should be observed when performing thisconversion. ASTM SI 10 provides guidelines for the
30、use of SIunits. Annex A of that standard provides conversion tables andAnnex B provides rules for conversion and significance.9. Special Tests9.1 The average grain size of forgings shall be ASTM No. 5or finer when tested in accordance with Test Methods E112.InTABLE 1 Mechanical RequirementsUltimate
31、TensileStrength, min,psi, (MPa)Yield Strength(0.2 % offset),min, psi (MPa)Elongation,Ain 2 in. or4D or 4W, min %Reduction inArea, min, %Hardness,HRC, min170 000 (1172) 120 000 (827) 12 12 35AElongation of material 0.063 in. (1.6 mm) or greater in diameter (D) or width (W) shall be measured using a g
32、auge length of 2 in. or 4D or 4W. The gauge length mustbe reported with the test results. The method for determining elongation of material under 0.063 in. (1.6 mm) in diameter or thickness may be negotiated. Alternately, agauge length corresponding to ISO 6892 may be used when agreed upon between s
33、upplier and purchaser. (5.65 sqaure root So, where So is the original cross sectionalarea.)F799 112forgings it may not be possible to fully recrystallize the entiremicrostructure to a fine grain size. Duplex microstructuresexhibiting areas of unrecrystallized grains as large as ASTMNo. 2 (or ALA No.
34、 2, as applicable, see Test Method E930)shall be acceptable provided a minimum of 50 % of the area ofeach section examined displays an average grain size ofASTMNo. 5 or finer; and the average microhardness of the largergrained regions is the equivalent of HRC 38 or greater. Inquantities of 10 % (by
35、area of the metallographic section inquestion) or less, unrecrystallized grains as large asASTM No.0 (or ALA No. 0, as applicable) shall be acceptable providedthe average microhardness of the larger grained regions is theequivalent of HRC 40 or greater.9.2 When specified by the purchaser, fluorescen
36、t penetrantinspection shall be performed on forgings. These penetrantinspections shall be performed in accordance with PracticesE165 and F601.10. Significance of Numerical Limits10.1 The following applies to all specified limits in thisspecification. To determine conformance to these limits, anobser
37、ved calculated value shall be rounded to the nearest unitin the last right hand digit used in expressing the specificationlimit, in accordance with the rounding method of Practice E29.11. Certification11.1 The supplier shall provide a certification of confor-mance that the material was tested in acc
38、ordance with thisspecification and met all requirements. A report of the testresults shall be furnished to the purchaser at the time ofshipment.12. Quality Program Requirements12.1 The alloy suppliers and any processors shall maintain aquality program as defined in ASQ C1 or ISO 9001.13. Keywords13.
39、1 cobalt alloys; cobalt alloys (for surgical implants);cobalt-chromium-molybdenum; forgings; metals (for surgicalimplants)APPENDIXES(Nonmandatory Information)X1. RATIONALEX1.1 The purpose for this specification is to characterizecomposition and properties to assure consistency in thermo-mechanically
40、 processed cobalt-28chromium-6molybdenumforgings used in the manufacturing of medical devices thatreceive no subsequent metallurgical processing.X1.2 Published data5,6indicate that material with a fine-grained homogeneous metallurgical structure resulting fromforging will be superior with respect to
41、 tensile strength andfatigue resistance compared to material conforming to Speci-fication F75. Based upon this, requirements include fine-grained microstructure and high tensile strength.X1.3 Some complex metallic phases, such as carbides,oxides, or carbonitrides, or combinations thereof, may bepres
42、ent in the microstructure of this alloy.X1.4 ISO standards are listed for reference only. Althoughthe ISO standards listed in Section 2 are similar to thecorrespondingASTM standards, they may not be identical. Useof an ISO standard in addition to or instead of a preferredASTM standard may be negotia
43、ted between the purchaser andsupplier.X1.5 Units of MeasureX1.5.1 ASTM PolicyASTM is promoting the use ofrationalized SI (metric) units in their standards. The F12.04Committee has modified this specification to facilitate thetransition by the medical materials industry to SI between nowand 2018. In
44、the first phase of this transition, running to 2013,the specifications will be structured to allow the use of either SIor inch-pound units. The choice of primary units in eachspecification will be determined by the industry using thespecification. The change to SI units during this period may beinit
45、iated by the purchaser through his purchase documentation.In the second phase of this transition the specifications will bewritten with SI as the primary units. Harmonization withcorresponding ISO documents should be considered whenassigning the SI values.5Bardos, D. I., “High Strength Co-Cr-Mo Allo
46、y for Prostheses,” CurrentConcepts of Internal Fixation of Fractures, edited by H. Uhthoff, Springer Verlag,New York, NY, 1980, p 111.6Weisman, S., “Vitallium FHS Forged High-Strength Alloy,” Current Conceptsof Internal Fixation of Fractures,p118.F799 113X2. BIOCOMPATIBILITYX2.1 The alloy compositio
47、n covered by this specificationhas been successfully employed in human implants for over adecade. This material has been found to produce a well-characterized level of local biological response when tested inaccordance with Practice F981 or equivalent.X2.2 The material composition conforming to this
48、 specifi-cation has been evaluated for biocompatibility and corrosionresistance and has been found to be comparable to materialconforming to Specification F75.X2.3 No known surgical implant material has ever beenshown to be completely free of adverse reactions in the humanbody; however, long-term cl
49、inical experience has shown anacceptable level of biological response can be expected, if thismaterial is used in appropriate applications.SUMMARY OF CHANGESCommitte F04 has identified the location of selected changes to this standard since the last issue (F799 06)that may impact the use of this standard. (Approved June 1, 2011)(1) Changed units of measure throughout the standard, so thatSI and inch-pound units are both considered to be standard.(2) Added Section 8 for Dimensions and Permissable Varia-tions, regarding units of measure.(3) Added X1.5 regarding units
