ASTM A839-02(2008)
(Specification)Standard Specification for Iron-Phosphorus Powder Metallurgy (P/M) Parts for Soft Magnetic Applications
Standard Specification for Iron-Phosphorus Powder Metallurgy (P/M) Parts for Soft Magnetic Applications
ABSTRACT
This specification covers parts produced from pressing and sintering of iron-phosphorus powders. The specification does not cover parts produced by metal injection molding. These parts are used in magnetic applications requiring higher permeability and electrical resistivity and lower coercive field strength than routinely attainable in parts produced from unalloyed iron powder. Two powder types are covered: Type I containing nominally 0.45% phosphorus, and Type II containing nominally 0.8% phosphorus. Apart from chemistry, parts produced to this specification shall have a minimum sintered density and maximum allowable coercive field strength. The minimum sintered density shall be 6.8 g/cm3 (6800 kg/m3) in the magnetically critical section of the part. Three grades with increasing maximum allowable coercive field strength are defined for each powder type. Detailed appendices showing the effect of sintering conditions on the magnetic and mechanical properties of parts made from both powders are included in this specification.
SCOPE
1.1 This specification covers parts produced from iron-phosphorus powder metallurgy materials. These parts are used in magnetic applications requiring higher permeability and electrical resistivity and lower coercive field strength than attainable routinely from parts produced from iron powder.
1.2 Two powder types are covered; Type I containing nominally 0.45 % phosphorus, and Type II containing nominally 0.8 % phosphorus.
1.3 This specification deals with P/M parts in the sintered or annealed condition. Should the sintered parts be subjected to any secondary operation that causes mechanical strain, such as machining or sizing, they should be resintered or annealed.
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
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Designation:A839 −02(Reapproved 2008)
Standard Specification for
Iron-Phosphorus Powder Metallurgy (P/M) Parts for Soft
Magnetic Applications
This standard is issued under the fixed designation A839; 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 Oil-Impregnated Bearings (Withdrawn 2009)
E1019 Test Methods for Determination of Carbon, Sulfur,
1.1 This specification covers parts produced from iron-
Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt
phosphorus powder metallurgy materials. These parts are used
Alloys by Various Combustion and Fusion Techniques
in magnetic applications requiring higher permeability and
electrical resistivity and lower coercive field strength than
3. Ordering Information
attainable routinely from parts produced from iron powder.
3.1 Purchase orders for parts conforming to this specifica-
1.2 Two powder types are covered; Type I containing
tion shall include the following information:
nominally 0.45 % phosphorus, and Type II containing nomi-
3.1.1 Reference to this specification and year of issue/
nally 0.8 % phosphorus.
revision.
3.1.2 The type of powder to be used (see 4.1 and Table 1).
1.3 This specification deals with P/M parts in the sintered or
3.1.3 Reference to an applicable part drawing.
annealed condition. Should the sintered parts be subjected to
3.1.4 Quantity required.
any secondary operation that causes mechanical strain, such as
3.1.5 Acritical cross section of the part shall be defined and
machining or sizing, they should be resintered or annealed.
so indicated on the applicable part drawing.The location of the
1.4 The values stated in inch-pound units are to be regarded
critical section is by mutual agreement between the user and
as standard. The values given in parentheses are mathematical
the producer (see 5.2).
conversions to SI units that are provided for information only
3.1.6 Magnetic property requirements if they are other than
and are not considered standard.
stated in Table 2.
3.1.7 Whethercertificationofchemicalanalysisormagnetic
2. Referenced Documents
property evaluation is required (see Sections 4 and 6).
2 3.1.8 Markingandpackagingrequirements(seeSection 11).
2.1 ASTM Standards:
3.1.9 Whether testing for magnetic aging is required.
A34/A34M Practice for Sampling and Procurement Testing
3.1.10 Exceptions to this specification or special require-
of Magnetic Materials
ments such as functional testing, as mutually agreed upon
A596/A596M Test Method for Direct-Current Magnetic
between the producer and the user.
Properties of Materials Using the Ballistic Method and
Ring Specimens
4. Chemical Composition
A773/A773M Test Method for dc Magnetic Properties of
4.1 The chemical composition of the parts shall conform to
Materials Using Ring and Permeameter Procedures with
the requirements prescribed in Table 1.
dc Electronic Hysteresigraphs
B328 Test Method for Density, Oil Content, and Intercon- 4.2 Chemical analysis for phosphorus shall be determined
nected Porosity of Sintered Metal Structural Parts and
by wet chemistry in accordance with a method to be agreed
upon between the user and the producer. Analysis of carbon,
oxygen, and nitrogen shall be done in accordance with Test
Methods E1019.
This specification is under the jurisdiction of ASTM Committee A06 on
Magnetic Properties and is the direct responsibility of Subcommittee A06.02 on
5. Sintered Density Requirements
Material Specifications.
Current edition approved May 1, 2008. Published June 2008. Originally
5.1 Magnetic and residual induction of P/M parts strongly
approved in 1985. Last previous edition approved in 2002 as A839–02. DOI:
depend on density. The density of P/M parts is determined by
10.1520/A0839-02R08.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
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A839−02 (2008)
TABLE 1 Chemical Composition Requirements (in Weight
Therefore, when requested by the user, the producer shall test
Percent)
for aging. To determine the susceptibility of the parts to aging,
Element Type I Type II
the test ring(s) should be heated for either 100 h at 150°C or
Phosphorus 0.40/0.50 0.75/0.85
600 h at 100°C and the coercive field strength remeasured. A
Carbon, max 0.03 0.03
change in coercive field strength of 10 % or more of the
Oxygen, max 0.10 0.10
original value is evidence that aging has occurred.
Nitrogen, max 0.01 0.01
A
Iron balance balance
6.7 Since magnetic properties are strongly affected by
A
Iron is the balance by difference. Quantitative analysis of this element is not
process conditions, refer to the Appendix X1-Appendix X3 for
required.
typical values and explanatory notes.
7. Workmanship, Finish, and Appearance
TABLE 2 Maximum Coercive Field Strength Requirements
7.1 The parts shall be uniform in composition and uniform
Grade Powder Type I (0.45 % P) Powder Type II (0.8 % P)
in density within critical sections.
1 1.4 Oe (110 A/m) 1.2 Oe (96 A/m)
2 1.8 Oe (140 A/m) 1.4 Oe (110 A/m)
7.2 If parts are sectioned or fractured, there shall be no
3 2.0 Oe (160 A/m) 1.7 Oe (140 A/m)
readily recognizable defects.
8. Sampling
the compressibility of the powder, the compacting pressure,
8.1 A lot shall consist of parts of the same form and
and sintering practice (temperature, time, and atmosphere).
dimensions, produced from a single mixed powder batch and
5.2 Parts produced in conformance with this specification from an unchanged process, without discontinuity in produc-
shall have a minimum sintered density of 6.8 g/cm (6800 tion, and submitted for inspection at one time.
kg/m ) in the critical section of the part. The critical section
8.2 The user and the producer shall agree upon a represen-
shall be defined by agreement between the user and the
tative number of specimens for testing.
producer.
9. Rejection and Rehearing
5.3 Sintered density shall be determined in accordance with
9.1 Parts that fail to conform to the requirements of this
Test Method B328.
specification may be rejected. Rejection should be reported to
6. Magnetic Property Requirements
the producer or supplier promptly and in writing. In case of
dissatisfaction with the results of the test, the producer or
6.1 Due to the nature of P/M parts production, magnetic
supplier may make claim for a rehearing.
testing of each lot is not required by this specification.
However, it is strongly recommended that the user require the
9.2 The disposition of rejected parts shall be subject to
producer to conduct periodic magnetic evaluations and to
agreement between the user and the producer.
certify the results obtained. Such magnetic property evalua-
10. Certification
tions shall be conducted in the following manner.
10.1 When specified in the purchase order or contract, the
6.2 When requested, each lot of parts should be sintered
user shall be furnished certification that samples representing
withatleastoneandpreferablythreeringtestspecimenswhich
each lot have either been tested or inspected as directed in this
comply with the geometric requirements listed in Practice
specification and the requirements have b
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