1、Designation: A 811 03 (Reapproved 2008)Standard Specification forSoft Magnetic Iron Parts Fabricated by Powder Metallurgy(P/M) Techniques1This standard is issued under the fixed designation A 811; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、 of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers parts produced from ironpowder metallurgy materials.1.2 This speci
3、fication deals with P/M parts in the sintered orannealed condition. Should the sintered parts be subjected toany secondary operation that causes mechanical strain, such asmachining or sizing, they should be resintered or annealed.1.3 The values stated in customary (cgs-emu and inch-pound) units are
4、to be regarded as standard. The values givenin parentheses are mathematical conversions to SI units whichare provided for information only and are not consideredstandard.2. Referenced Documents2.1 ASTM Standards:2A 34/A 34M Practice for Sampling and Procurement Test-ing of Magnetic MaterialsA 340 Te
5、rminology of Symbols and Definitions Relating toMagnetic TestingA 596/A 596M Test Method for Direct-Current MagneticProperties of Materials Using the Ballistic Method andRing SpecimensA 773/A 773M Test Method for dc Magnetic Properties ofMaterials Using Ring and Permeameter Procedures withdc Electro
6、nic HysteresigraphsB 328 Test Method for Density, Oil Content, and Intercon-nected Porosity of Sintered Metal Structural Parts andOil-Impregnated BearingsE 1019 Test Methods for Determination of Carbon, Sulfur,Nitrogen, and Oxygen in Steel, Iron, Nickel, and CobaltAlloys by Various Combustion and Fu
7、sion Techniques3. Terminology3.1 The terms and symbols used in this specification aredefined in Terminology A 340.4. Ordering Information4.1 Purchase orders for parts conforming to this specifica-tion shall include the following information:4.1.1 Reference to this specification and year of issue/rev
8、ision,4.1.2 Reference to an applicable part drawing,4.1.3 Quantity required,4.1.4 A critical cross section of the part shall be defined andso indicated on the applicable part drawing. The location of thecritical section is by mutual agreement between the purchaserand the producer (6.2),4.1.5 Magneti
9、c property requirements if they are other thanstated in Table 1,4.1.6 Whether certification of chemical analysis or magneticproperty evaluation is required (Sections 5 and 7),4.1.7 Marking and packaging requirements (Section 12),and4.1.8 Exceptions to this specification or special require-ments such
10、 as functional testing as mutually agreed uponbetween the producer and the purchaser.5. Chemical Composition5.1 The chemical composition of the parts shall conform tothe requirements prescribed in Table 2.5.2 Determination of metallic constituents shall be by amethod acceptable to both the producer
11、and the purchaser.Analysis of carbon, oxygen, sulfur, and nitrogen shall be donein accordance with Test Methods E 1019.6. Sintered Density Requirements6.1 Magnetic and residual induction of P/M parts stronglydepend on density. The density of P/M parts is determined bythe compressibility of the powde
12、r, the compacting pressure,and sintering practice (temperature, time, and atmosphere).1This specification is under the jurisdiction of ASTM Committee A06 onMagnetic Properties and is the direct responsibility of Subcommittee A06.02 onMaterial Specifications.Current edition approved Nov. 1, 2008. Pub
13、lished December 2008. Originallyapproved in 1983. Last previous edition approved in 2003 as A 811 03.2For 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 D
14、ocument Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.2 Parts produced in conformance with this specificationshall have a minimum sintered density of 6.6 g/cm3(6600kg/m3) in the critical section of
15、 the part. The critical sectionshall be defined by agreement between the purchaser and theproducer.6.3 Sintered density shall be determined in accordance withTest Method B 328.7. Magnetic Property Requirements7.1 Because of the nature of P/M parts production, magnetictesting of each lot is not requi
16、red by this specification.However, it is strongly recommended that the purchaserrequire the producer to conduct periodic magnetic evaluationsand to certify such results. Such magnetic property evaluationsshall be conducted in the following manner.7.2 When requested, each lot of parts should be sinte
17、redwith at least one and preferably three ring test specimens whichcomply with the geometric requirements listed in PracticeA 34/A 34M. The ring specimen(s) shall be produced from thesame mixed lot of powder used to produce the parts.7.3 The magnetic properties shall be determined in accor-dance wit
18、h Test Methods A 596/A 596M or A 773/A 773M.7.4 For the purpose of this specification, only the coercivefield strength determined from a maximum applied magneticfield strength of 15 Oe (1200 A/m) needs to be determined.Other magnetic properties may be specified by mutual agree-ment between the purch
19、aser and the producer.7.5 Coercive Field Strength RequirementsThree grades,defined by coercive field strength, are stipulated by thisspecification and are listed in Table 1. The coercive fieldstrength requirement for Grade 3 was developed from inter-laboratory study. The values for Grades 1 and 2 ar
20、e based on aliterature review and are believed to reflect the current industrycapabilities.7.6 Magnetic AgingNitrogen introduced during sinteringcan cause time-dependent degradation of magnetic properties.Therefore, when requested by the purchaser, the producer shalltest for aging. To determine the
21、susceptibility of the parts toaging, the test ring(s) should be heated for either 100 h at 1506 5C or 600 h at 100 6 5C and the coercive field strengthremeasured. A change in coercive field strength of 10 % ormore of the original value is evidence that aging has occurred.7.7 Since magnetic propertie
22、s are strongly affected byprocess conditions, refer toAppendix X1 for typical values andexplanatory notes.8. Workmanship, Finish and Appearance8.1 The parts shall be uniform in composition and uniformin density within critical sections.8.2 If parts are sectioned or fractured, there shall be noreadil
23、y recognizable defects.9. Sampling9.1 A lot shall consist of parts of the same form anddimensions, produced from a single mixed powder batch andfrom an unchanged process, without discontinuity in produc-tion, and submitted for inspection at one time.9.2 The purchaser and producer shall agree upon a
24、repre-sentative number of specimens for testing.10. Rejection and Rehearing10.1 Parts that fail to conform to the requirements of thisspecification shall be rejected. Rejection should be reported tothe producer or supplier promptly and in writing. In case ofdissatisfaction with the results of the te
25、st, the producer orsupplier may make claim for a rehearing.10.2 The disposition of rejected parts shall be subject toagreement between the purchaser and the producer.11. Certification11.1 When specified in the purchase order or contract, thepurchaser shall be furnished certification that samples rep
26、re-senting each lot have either been tested or inspected as directedin this specification and the requirements have been met.11.2 When specified in the purchase order or contract, areport of the test results shall include the following:11.2.1 Chemical composition,11.2.2 Part density in the critical
27、section,11.2.3 Magnetic test results, if required by purchaser, and11.2.4 The results of any other tests stipulated in thepurchase order or contract.12. Packaging and Package Marking12.1 Packaging shall be subject to agreement between thepurchaser and the producer.12.2 Parts furnished under this spe
28、cification shall be in acontainer identified by the name or symbol of the partsproducer.13. Keywords13.1 coercive field strength; iron; P/M parts; powder met-allurgy (P/M)TABLE 1 Maximum Coercive Field Strength RequirementsGrade Coercive Field Strength1 1.8 Oe (140 A/m)2 2.0 Oe (160 A/m)3 2.3 Oe (18
29、0 A/m)TABLE 2 Chemical Requirements (weight percent)Element %Carbon, max 0.03Oxygen, max 0.10Nitrogen, max 0.01OthersA0.50, maxIronBbalanceAOthers refers to trace elements which are to be regarded as incidental and notdeliberate additions.BIron is the balance by difference. Quantitative analysis of
30、this element is notrequired.A 811 03 (2008)2APPENDIX(Nonmandatory Information)X1. TYPICAL MAGNETIC AND MECHANICAL PROPERTIESX1.1 Typical magnetic and mechanical properties, based oninterlaboratory studies, are listed in Table X1.1, Table X1.2,and Table X1.3. Table X1.1 contains properties typicallya
31、chieved when sintering is conducted at 1120C in dissociatedammonia. Table X1.2 contains properties typically achievedwhen sintering is conducted at 1120C in dry hydrogen or in avacuum. Table X1.3 contains properties typically achievedwhen sintering is conducted at 1260C in dry hydrogen or in avacuum
32、. The influence of sintered density is shown in all threetables. The data provided are for information only and are notrequirements in this specification.X1.2 Maximum flux density, residual induction, and coer-cive field strength are measured from a maximum appliedmagnetic field strength of 15 Oe (1
33、200 A/m).TABLE X1.1 1120C Sinter in Dissociated AmmoniaSintered Density (g/cm3) (kg/m3)6.666006.969007.27200(Relative) maximum permeability 1 700 2 100 2 700Maximum flux density (G) 9 000 10 500 12 000(T) 0.90 1.05 1.20Residual induction (G) 7 800 9 000 10 500(T) 0.78 0.90 1.05Coercive field strengt
34、h (Oe) 2.1 2.1 2.1(A/m) 170 170 1700.2 % offset yield strength (psi) 11 000 17 000 22 500(MPa) 76 120 155Ultimate tensile strength (psi) 18 000 27 500 37 000(MPa) 120 190 260Percent elongation, 1 in. (25.4 mm) 6 11 16Apparent hardness (HRF) 40 50 55A 811 03 (2008)3ASTM International takes no positio
35、n respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.
36、This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM I
37、nternational Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address sho
38、wn below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832
39、-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE X1.2 1120C Sinter in Dry Hydrogen or VacuumSintered Density (g/cm3) (kg/m3)6.666006.969007.27200(Relative) maximum permeability 1 800 2 300 2 900Maximum flux density (G) 9 500 10 500 12 000(T) 0.95 1.05 1.20Res
40、idual induction (G) 8 200 9 700 11 000(T) 0.82 0.97 1.10Coercive field strength (Oe) 1.8 1.8 1.8(A/m) 140 140 1400.2 % offset yield strength (psi) 11 000 17 000 22 500(MPa) 76 120 155Ultimate tensile strength (psi) 19 000 28 000 37 500(MPa) 130 190 259Percent elongation in 1 in. (25.4 mm) 8 12 17App
41、arent hardness (HRF) 40 50 55TABLE X1.3 1260C Sinter in Dry Hydrogen or VacuumSintered Density (g/cm3) (kg/m3)6.666006.969007.27200(Relative) maximum permeability 2 800 3 300 3 800Maximum flux density (G) 10 000 11 500 13 000(T) 1.05 1.20 1.30Residual induction (G) 8 500 10 000 11 500(T) 0.85 1.0 1.15Coercive field strength (Oe) 1.6 1.6 1.6(A/m) 120 120 1200.2 % offset yield strength (psi) 10 000 16 000 21 000(MPa) 69 110 140Ultimate tensile strength (psi) 20 000 29 000 38 000(MPa) 140 200 260Percent elongation in 1 in. (25.4 mm) 10 15 20Apparent hardness (HRF) 38 45 50A 811 03 (2008)4
