ASTM F2886-17(2023)
(Specification)Standard Specification for Metal Injection Molded Cobalt-28Chromium-6Molybdenum Components for Surgical Implant Applications
Standard Specification for Metal Injection Molded Cobalt-28Chromium-6Molybdenum Components for Surgical Implant Applications
ABSTRACT
This specification covers chemical, mechanical, and metallurgical general requirements for metal injection molded (MIM) cobalt-28chromium-6molybddenum components to be used in manufacturing surgical implants. In this specification, the MIM components covered may have been densified beyond their as-sintered density by post-sinter processing. For the chemical requirements, the components supplied in this specification must conform in accordance to the chemical requirements specified herein in Table 1. The product analysis tolerances must also conform to the product tolerances presented in Table 2. The specification also enumerates the mechanical requirements for MIM components wherein the tensile properties of the MIM must conform to the mechanical properties in Table 3. The microstructural requirements and specimen preparation shall be in accordance with Guide E3 and Practice E407.
SCOPE
1.1 This specification covers chemical, mechanical, and metallurgical requirements for metal injection molded (MIM) cobalt-28chromium-6molybdenum components to be used in the manufacture of surgical implants
1.2 The MIM components covered by this specification may have been densified beyond their as-sintered density by post-sinter processing.
1.3 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F2886 − 17 (Reapproved 2023)
Standard Specification for
Metal Injection Molded Cobalt-28Chromium-6Molybdenum
Components for Surgical Implant Applications
This standard is issued under the fixed designation F2886; the number immediately following the designation indicates the year 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.
1. Scope E29 Practice for Using Significant Digits in Test Data to
Determine Conformance with Specifications
1.1 This specification covers chemical, mechanical, and
E165/E165M Practice for Liquid Penetrant Testing for Gen-
metallurgical requirements for metal injection molded (MIM)
eral Industry
cobalt-28chromium-6molybdenum components to be used in
E354 Test Methods for Chemical Analysis of High-
the manufacture of surgical implants
Temperature, Electrical, Magnetic, and Other Similar Iron,
1.2 The MIM components covered by this specification may
Nickel, and Cobalt Alloys
have been densified beyond their as-sintered density by post-
E407 Practice for Microetching Metals and Alloys
sinter processing.
F75 Specification for Cobalt-28 Chromium-6 Molybdenum
Alloy Castings and Casting Alloy for Surgical Implants
1.3 Units—The values stated in either SI units or inch-
pound units are to be regarded separately as standard. The (UNS R30075)
F601 Practice for Fluorescent Penetrant Inspection of Me-
values stated in each system may not be exact equivalents;
therefore, each system shall be used independently of the other. tallic Surgical Implants
F629 Practice for Radiography of Cast Metallic Surgical
Combining values from the two systems may result in noncon-
formance with the standard. Implants
F1537 Specification for Wrought Cobalt-28Chromium-
1.4 This international standard was developed in accor-
6Molybdenum Alloys for Surgical Implants (UNS
dance with internationally recognized principles on standard-
R31537, UNS R31538, and UNS R31539)
ization established in the Decision on Principles for the
IEEE/ASTM SI 10 American National Standard for Use of
Development of International Standards, Guides and Recom-
the International System of Units (SI): The Modern Metric
mendations issued by the World Trade Organization Technical
System
Barriers to Trade (TBT) Committee.
2.2 ISO Standards:
ISO 6892 Metallic Materials Tensile Testing at Ambient
2. Referenced Documents
Temperature
2.1 ASTM Standards:
ISO 9001 Quality Management Systems—Requirements
B243 Terminology of Powder Metallurgy
2.3 AMS Standards:
B311 Test Method for Density of Powder Metallurgy (PM)
AMS 2269 Chemical Check Analysis Limits, Nickel, Nickel
Materials Containing Less Than Two Percent Porosity
Alloys and Cobalt Alloys
B923 Test Method for Metal Powder Skeletal Density by
AMS 2248 Chemical Check Analysis Limits, Corrosion and
Helium or Nitrogen Pycnometry
Heat Resistant Steels and Alloys, Maraging and Other
E3 Guide for Preparation of Metallographic Specimens
Highly-Alloyed Steels, and Iron Alloys
E8/E8M Test Methods for Tension Testing of Metallic Ma-
2.4 MPIF Standards:
terials
MPIF Standard 10 Determination of the Tensile Properties of
Powder Metallurgy Materials
MPIF Standard 42 Determination of Density of Compacted
This specification is under the jurisdiction of ASTM Committee F04 on
or Sintered Powder Metallurgy Products
Medical and Surgical Materials and Devices and is the direct responsibility of
Subcommittee F04.12 on Metallurgical Materials.
Current edition approved Sept. 1, 2023. Published September 2023. Originally
approved in 2010. Last previous edition approved in 2017 as F2886 – 17. DOI Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/F2886-17R23. 4th Floor, New York, NY 10036, http://www.ansi.org.
2 4
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from American Society for Quality (ASQ), 600 N. Plankinton Ave.,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Milwaukee, WI 53203, http://www.asq.org.
Standards volume information, refer to the standard’s Document Summary page on Available from Metal Powder Industries Federation (MPIF), 105 College Road
the ASTM website. East, Princeton, New Jersey 08540, http://www.mpif.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2886 − 17 (2023)
MPIF Standard 50 Preparing and Evaluating Metal Injection 4.1.2 ASTM specification and date of issue,
Molded Sintered/Heat Treated Tension Specimens 4.1.3 Alloy 1 (low carbon) or Alloy 2 (high carbon),
MPIF Standard 63 Density Determinations of MIM Compo- 4.1.4 Units to be certified—SI or inch-pound,
nents (Gas Pycnometry) 4.1.5 Component configuration (engineering drawing
MPIF Standard 64 Terms Used in Metal Injection Molding and/or 3D solid model) and dimensional requirements,
4.1.6 Condition (5.3),
3. Terminology 4.1.7 Mechanical properties (if applicable),
4.1.8 Finish (5.3),
3.1 Definitions of Terms Specific to This Standard:
4.1.9 Special tests (Section 9, Section 10), if any, and
3.1.1 Definitions of powder metallurgy and MIM terms can
4.1.10 Other requirements.
be found in Terminology B243 and MPIF Standard 64.
Additional descriptive information is available in the Related
5. Materials and Manufacture
Material Section of Vol 02.05 of the Annual Book of ASTM
5.1 Components conforming to this specification shall be
Standards.
produced by the metal injection molding process using preal-
3.1.2 absolute density, n—the value of density used to
loyed metal powders with major elemental composition meet-
characterize a powder material with a particular chemical
ing the chemical requirements of Table 1.
composition as if it were a fully dense material, completely
free of porosity.
5.2 Post-sintering operations may be employed to achieve
3.1.2.1 Discussion—For the purposes of this specification,
the desired density, shape, size, surface finish, or other com-
the skeletal density (also referred to as pycnometer density)
ponent properties. The post-sintering operations to be used
measured on the raw material powders using the pycnometry
shall be agreed upon between the supplier and purchaser.
method of Test Method B923 will be used to represent the
5.3 The condition and finish of the components shall be
absolute density of the particular chemical composition.
agreed upon between the supplier and purchaser.
3.1.3 debinding, n—a step between molding and sintering
where the majority of the binder used in molding is extracted
6. Chemical Requirements
by heat, solvent, a catalyst, or other techniques.
6.1 The components supplied under this specification shall
3.1.4 feedstock, n—in metal injection molding, a moldable
conform to the chemical requirements in Table 1. The supplier
mixture of metal powder and binder.
shall not ship components with chemistry outside the require-
3.1.5 feedstock batch, n—a specified quantity of feedstock ments specified in Table 1.
made up of the same lot of metallic powders and the same lot 6.1.1 Chemical analysis of a finished component or repre-
of binder materials mixed under the same conditions at sentative sample shall be used for reporting all chemical
essentially the same time. requirements. Any representative samples shall be produced
from the same feedstock batch, debound, sintered, and post
3.1.6 lot, n—a specified quantity of components made up of
processed concurrently with the finished components they
the same batch of feedstock, debound, sintered, and post
represent.
processed under the same conditions at essentially the same
6.1.2 Requirements for the major and minor elemental
time.
constituents are listed in Table 1. Also listed are important
3.1.7 metal injection molded component, n—product fabri-
cated by a metal injection molding process consisting of
mixing metal powders with binders to make a feedstock,
TABLE 1 Chemical Requirements
introducing this feedstock into a mold by injection or other
Chemical Composition Chemical Composition
means, debinding to remove the binders, and sintering.
Alloy 1 Alloy 2
Element (Low Carbon) (High Carbon)
3.1.8 pre-alloyed powder, n—powder composed of two or
(% mass/mass) (% mass/mass)
more elements that are alloyed in the powder manufacturing
min max min max
process in which the particles are of the same nominal
Carbon . 0.14 0.15 0.35
Chromium 27.0 30.0 27.0 30.0
composition throughout.
Molybdenum 5.0 7.0 5.0 7.0
3.1.9 relative density, n—the density ratio, often expressed
Nickel . 0.5 . 0.5
Iron . 0.75 . 0.75
as a percentage, of the density of a porous material to the
Silicon . 1.0 . 1.0
absolute density of the same material, completely free of
Manganese . 1.0 . 1.0
porosity.
Tungsten . 0.20 . 0.20
Phosphorus . 0.020 . 0.020
3.1.10 sintering—the metallurgical bonding of particles in a
Sulfur . 0.010 . 0.010
MIM component resulting from a thermal treatment at a
Nitrogen . 0.25 . 0.25
Aluminum . 0.10 . 0.10
temperature below the melting point of the main constituent.
Titanium . 0.10 . 0.10
Boron . 0.010 . 0.010
A
4. Ordering Information Cobalt . Balance . Balance
A
Approximately equal to the difference of 100 % and the sum percentage of the
4.1 Include with inquiries and orders for material under this
other specified elements. The percentage of the cobalt difference is not required to
specification the following information:
be reported.
4.1.1 Quantity,
F2886 − 17 (2023)
residual elements. The percentage of cobalt is determined by 7.1.1 The components supplied under this specification
difference and need not be determined or certified. shall conform to the mechanical property requirements in Table
6.1.3 All commercial metals contain small amounts of 3.
elements other than those which are specified. It is neither 7.1.2 Test specimens shall be taken from a MIM component
practical nor necessary to specify limits for unspecified if possible, or from a representative sample or molded tensile
elements, whether residual elements or trace elements, that can specimen. A representative sample or molded tensile specimen
be present. The producer is permitted to analyze for unspecified may only be used if the component configuration is such that
elements and is permitted to report such analyses. The presence a tensile specimen cannot be obtained from the component.
of an unspecified element and the reporting of an analysis for
7.2 Representative samples or molded tensile specimens
that element shall not be a basis for rejection.
shall be produced from the same feedstock batch, debound,
6.1.4 Intentional elemental additions other than those speci-
sintered, and post processed concurrently with the finished
fied in Table 1 are not permitted.
components that they represent.
6.1.5 Analysis for elements not listed in Table 1 is not
7.2.1 Test specimens machined from components or repre-
required to verify compliance with this specification.
sentative samples shall be ground or machined to final dimen-
6.2 Product Analysis: sions in accordance Test Methods E8/E8M.
6.2.1 Product analysis tolerances do not broaden the speci- 7.2.2 Alternate tensile specimen geometries may be agreed
fied heat analysis requirements, but cover variations in the upon by the purchaser and supplier. Some examples of the
measurement of chemical content between laboratories. The configurations for molded tensile specimens are described in
product analysis tolerances shall conform to the product MPIF Standard 10 and MPIF Standard 50.
tolerances in Table 2.
7.3 Specimens for tensile tests shall be tested in accordance
6.2.2 The product analysis is either for the purpose of
with Test Methods E8/E8M.
verifying the composition of the manufacturing lot or to
7.4 Should any test piece not meet the specified
determine variations in the composition within the lot. Accep-
requirements, test two additional representative test pieces, in
tance or rejection of the manufacturing lot of components may
the same manner, for each failed test piece. The lot shall be
be made by the purchaser on the basis of this product analysis.
considered in compliance only if all additional test pieces meet
6.2.3 Samples for chemical analysis shall be representative
the specified requirements.
of the components being tested.
6.2.4 Product analysis outside the tolerance limits allowed
7.5 Tensile test results for which any specimen fractures
in Table 2 is cause for rejection of the product. A referee outside the gauge length shall be considered valid if both the
analysis may be used if agreed upon by the supplier and
elongation and reduction of area meet the minimum require-
purchaser. ments specified. Refer to subsections 7.11.4 and 7.11.5 of Test
6.2.5 For referee purposes, use Test Methods E354 or other
Methods E8/E8M. If either the elongation or reduction of area
analytical methods agreed upon between the purchaser and the is less than the minimum requirement, invalidate the specimen
supplier. and retest. Retest one specimen for each invalidated specimen.
8. Dimensions and Permissible Variation
7. Mechanical Requirements
8.1 Units of Measure:
7.1 Tensile Properties:
8.2 Selection—This specification requires that the purchaser
selects the units (SI or inch-pound) to be used for product
A,B
certification. In the absence of a stated selection of units on the
TABLE 2 Product Analysis Tolerance
purchase order, this selection may be expressed by the pur-
Tolerance Under the Minimum or
Element Over the Maximum Limit chaser in several alternate forms listed in order of precedence.
C
Composition (% mass/mass)
Carbon 0.02
Chromium 0.30
TABLE 3 Mechanical Requirements
Molybdenum 0.15
Nickel 0.05
Relative Density
Iron 0.03 Alloy 1 (Low Carbon) Alloy 2 (High Carbon)
Silicon 0.05 MPa [psi] MPA [psi]
Manganese 0.03 Ultimate Tensile 725 [105 000] min 825 [120 000] min
Tungsten 0.04 Strength
Phosphorus 0.005 Yield Strength (0.2 % 450 [65 000] min 480 [70 000] min
Sulfur 0.003 offset)
D A
Nitrogen 0.02 Elongation 10 % min 10 % min
Aluminum 0.02 Reduction of Area 10 % min 10 % min
Titanium 0.02
A
Elongation of material 1.575 mm [0.062 in.] or greater in diameter (D) or width
Boron 0.002
(W) shall be measured using a gauge length of 2 in. or 4D or 4W. The gauge length
A
See Test Methods E354. shall be reported with the test results. The method for determining elongation of
B
See AMS 2269 for chemical check analysis limits except nitrogen. material unde
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