ASTM A811-97

Standard Specification for Soft Magnetic Iron Parts Fabricated by Powder Metallurgy (P/M) Techniques

SCOPE
1.1 This specification covers parts produced from iron powder metallurgy materials.

General Information

• Status: Historical
• Publication Date: 09-Apr-1997
• ICS: 77.160 - Powder metallurgy
• Technical Committee: A06 - Magnetic Properties
• Drafting Committee: A06.02 - Material Specifications

Relations

• Replaced By: ASTM A811-03 - Standard Specification for Soft Magnetic Iron Parts Fabricated by Powder Metallurgy (P/M) Techniques
• Effective Date: 10-May-2003
• Referred By: ASTM A848-17 - Standard Specification for Low-Carbon Magnetic Iron
• Effective Date: 10-Apr-1997
• Referred By: ASTM A1126-23 - Standard Specification for Magnetic Pure Iron
• Effective Date: 10-Apr-1997
• Referred By: ASTM B925-15(2022) - Standard Practices for Production and Preparation of Powder Metallurgy (PM) Test Specimens
• Effective Date: 10-Apr-1997

Standards Content (Sample)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: A 811 – 97
Standard Specification for
Soft Magnetic Iron Parts Fabricated by Powder Metallurgy
(P/M) Techniques
This standard is issued under the fixed designation A 811; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
1.1 This specification covers parts produced from iron 3.1 The terms and symbols used in this specification are
powder metallurgy materials. defined in Terminology A 340.
1.2 This specification deals with P/M parts in the sintered or
4. Ordering Information
annealed condition. Should the sintered parts be subjected to
4.1 Purchase orders for parts conforming to this specifica-
any secondary operation that causes mechanical strain, such as
machining or sizing, they should be resintered or annealed. tion shall include the following information.
4.1.1 Reference to this specification and year of issue/
1.3 The values stated in either customary (cgs-emu and
inch-pound) units or SI units are to be regarded separately as revision.
4.1.2 Reference to an applicable part drawing.
standard. Within the text, the SI units are shown in brackets.
The values stated in each system are not exact equivalents; 4.1.3 Quantity required.
4.1.4 A critical cross section of the part shall be defined and
therefore, each system shall be used independently of the other.
Combining values from the two systems may result in noncon- so indicated on the applicable part drawing. The location of the
critical section is by mutual agreement between the purchaser
formance with this specification.
and the producer (6.2).
2. Referenced Documents
4.1.5 Magnetic property requirements if they are other than
2.1 ASTM Standards: stated in Table 1.
A 34 Practice for Sampling and Procurement Testing of 4.1.6 Whether certification of chemical analysis or magnetic
Magnetic Materials property evaluation is required (Sections 5 and 7).
A 340 Terminology of Symbols and Definitions Relating to 4.1.7 Marking and packaging requirements (Section 12).
Magnetic Testing 4.1.8 Exceptions to this specification or special require-
A 596 Test Method for Direct-Current Magnetic Properties ments such as functional testing as mutually agreed upon
of Materials Using the Ballistic Method and Ring Speci- between the producer and the purchaser.
mens
5. Chemical Composition
A 773 Test Method for D-C Magnetic Properties of Mate-
5.1 The chemical composition of the parts shall conform to
rials Using Ring and Permeameter Procedures with D-C
Electronic Hysteresigraphs the requirements prescribed in Table 2.
5.2 Determination of metallic constituents shall be by a
B 328 Test Method for Density, Oil Content, and Intercon-
nected Porosity of Sintered Metal Structural Parts and method acceptable to both the producer and the purchaser.
Analysis of carbon, oxygen, sulfur, and nitrogen shall be done
Oil-Impregnated Bearings
E 1019 Test Methods for Determination of Carbon, Sulfur, in accordance with Test Methods E 1019.
Nitrogen, and Oxygen in Steel and in Iron, Nickel, and
6. Sintered Density Requirements
Cobalt Alloys
6.1 Magnetic and residual induction of P/M parts strongly
depend on density. The density of P/M parts is determined by
This specification is under the jurisdiction of ASTM Committee A-6 on
the compressibility of the powder, the compacting pressure,
Magnetic Properties and is the direct responsibility of Subcommittee A06.02 on
and sintering practice (temperature, time, and atmosphere).
Material Specifications.
6.2 Parts produced in conformance with this specification
Current edition approved April 10, 1997. Published December 1997. Originally
shall have a minimum sintered density of 6.6 g/cm [6600
published as A 811 – 83. Last previous edition A 811 – 90.
2 3
Annual Book of ASTM Standards, Vol 03.04.
kg/m ] in the critical section of the part. The critical section
Annual Book of ASTM Standards, Vol 02.05.
Annual Book of ASTM Standards, Vol 03.06.
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
A811
TABLE 1 Maximum Coercive Field Strength Requirements
6 5°C or 600 h at 100 6 5°C and the coercive field strength
Grade Coercive Field Strength remeasured. A change in coercive field strength of 10 % or
more of the original value is evidence that aging has occurred.
1 1.8 Oe [140 A/m]
2 2.0 Oe [160 A/m]
7.7 Since magnetic properties are strongly affected by
3 2.3 Oe [180 A/m]
process conditions, refer to Appendix X1 for typical values and
explanatory notes.
TABLE 2 Chemical Requirements (weight percent)
8. Workmanship, Finish and Appearance
Element %
8.1 The parts shall be uniform in composition and uniform
Carbon, max 0.03
in density within critical sections.
Oxygen, max 0.10
8.2 If parts are sectioned or fractured, there shall be no
Nitrogen, max 0.01
A
Others 0.50, max
readily recognizable defects.
B
Iron balance
A
9. Sampling
Others refers to trace elements which are to be regarded as incidental and not
deliberate additions.
9.1 A lot shall consist of parts of the same form and
B
Iron is the balance by difference. Quantitative analysis of this element is not
required. dimensions, produced from a single mixed powder batch and
from an unchanged process, without discontinuity in produc-
shall be defined by agreement between the purchaser and the tion, and submitted for inspection at one time.
9.2 The purchaser and producer shall agree upon a repre-
producer.
6.3 Sintered density shall be determined in accordance with sentative number of specimens for testing.
Test Method B 328.
10. Rejection and Rehearing
7. Magnetic Property Requirements
10.1 Parts that fail to conform to the requirements of this
7.1 Because of the nature of P/M parts production, magnetic specification shall be rejected. Rejection should be reported to
testing of each lot is not required by this specification.
the producer or supplier promptly and in writing. In case of
However, it is strongly recommended that the purchaser dissatisfaction with the results of the test, the producer or
require the producer to conduct periodic magnetic evaluations
supplier may make claim for a rehearing.
and to certify such results. Such magnetic property evaluations 10.2 The dis
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