1、Designation: A 811 03Standard 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 of revision, the
2、year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 specification deals wi
3、th 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 to be regarded as
4、 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:A 34/A 34M Practice for Sampling and Procurement Test-ing of Magnetic Materials2A 340 Terminology of Symb
5、ols and Definitions Relating toMagnetic Testing2A 596 Test Method for Direct-Current Magnetic Propertiesof Materials Using the Ballistic Method and Ring Speci-mens2A 773 Test Method for dc Magnetic Properties of MaterialsUsing Ring and Permeameter Procedures with dc Elec-tronic Hysteresigraphs2B 328
6、 Test Method for Density, Oil Content, and Intercon-nected Porosity of Sintered Metal Structural Parts andOil-Impregnated Bearings3E 1019 Test Methods for Determination of Carbon, Sulfur,Nitrogen, and Oxygen in Steel and in Iron, Nickel, andCobalt Alloys43. Terminology3.1 The terms and symbols used
7、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/revision,4.1.2 Reference to an applicable part drawing,4.1.3 Qu
8、antity 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 Magnetic property requirements if they are other thanstated in Tabl
9、e 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 as functional testing as mutually agreed uponbetween the pr
10、oducer 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 and the purchaser.Analysis of carbon, oxygen, sulfur, and ni
11、trogen 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 powder, the compacting pressure,and sintering practice (temperatu
12、re, 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 May 10, 2003. Published June 2003. Originallyapproved in 1983. Last previous
13、edition approved in 1997 as A 811 97.2Annual Book of ASTM Standards, Vol 03.04.3Annual Book of ASTM Standards, Vol 02.05.4Annual Book of ASTM Standards, Vol 03.05.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.2 Parts produced in
14、conformance with this specificationshall have a minimum sintered density of 6.6 g/cm3(6600kg/m3) in the critical section of 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
15、. Magnetic Property Requirements7.1 Because of the nature of P/M parts production, magnetictesting of each lot is not required by this specification.However, it is strongly recommended that the purchaserrequire the producer to conduct periodic magnetic evaluationsand to certify such results. Such ma
16、gnetic property evaluationsshall be conducted in the following manner.7.2 When requested, each lot of parts should be sinteredwith 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 fr
17、om thesame mixed lot of powder used to produce the parts.7.3 The magnetic properties shall be determined in accor-dance with Test Methods A 596 or A 773.7.4 For the purpose of this specification, only the coercivefield strength determined from a maximum applied magneticfield strength of 15 Oe (1200
18、A/m) needs to be determined.Other magnetic properties may be specified by mutual agree-ment between the purchaser 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 fiel
19、dstrength requirement for Grade 3 was developed from inter-laboratory study. The values for Grades 1 and 2 are based on aliterature review and are believed to reflect the current industrycapabilities.7.6 Magnetic AgingNitrogen introduced during sinteringcan cause time-dependent degradation of magnet
20、ic properties.Therefore, when requested by the purchaser, the producer shalltest for aging. To determine the 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 s
21、trength of 10 % ormore of the original value is evidence that aging has occurred.7.7 Since magnetic properties are strongly affected byprocess conditions, refer to Appendix X1 for typical values andexplanatory notes.8. Workmanship, Finish and Appearance8.1 The parts shall be uniform in composition a
22、nd uniformin density within critical sections.8.2 If parts are sectioned or fractured, there shall be noreadily 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 discontinui
23、ty in produc-tion, and submitted for inspection at one time.9.2 The purchaser and producer shall agree upon a 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 rep
24、orted tothe producer or supplier promptly and in writing. In case ofdissatisfaction with the results of the test, 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 Wh
25、en specified in the purchase order or contract, thepurchaser shall be furnished certification that samples repre-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
26、 the test results shall include the following:11.2.1 Chemical composition,11.2.2 Part density in the critical 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 Pac
27、kaging shall be subject to agreement between thepurchaser and the producer.12.2 Parts furnished under this specification 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 Coe
28、rcive Field Strength RequirementsGrade Coercive Field Strength1 1.8 Oe (140 A/m)2 2.0 Oe (160 A/m)3 2.3 Oe (180 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 re
29、garded as incidental and notdeliberate additions.BIron is the balance by difference. Quantitative analysis of this element is notrequired.A811032APPENDIX(Nonmandatory Information)X1. TYPICAL MAGNETIC AND MECHANICAL PROPERTIESX1.1 Typical magnetic and mechanical properties, based oninterlaboratory st
30、udies, are listed in Table X1.1, Table X1.2,and Table X1.3. Table X1.1 contains properties typicallyachieved 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 con
31、tains properties typically achievedwhen sintering is conducted at 1260C in dry hydrogen or in avacuum. 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
32、, and coer-cive field strength are measured from a maximum appliedmagnetic field strength of 15 Oe (1200 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 0
33、00(T) 0.90 1.05 1.20Residual induction (G) 7 800 9 000 10 500(T) 0.78 0.90 1.05Coercive field strength (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.
34、 (25.4 mm) 6 11 16Apparent hardness (HRF) 40 50 55A811033ASTM International takes no position 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 paten
35、t rights, and the riskof infringement of such rights, are entirely their own responsibility.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 eithe
36、r for revision of this standard or for additional standardsand should be addressed to ASTM International 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 he
37、aring you shouldmake your views known to the ASTM Committee on Standards, at the address shown 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 standar
38、d may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (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 per
39、meability 1 800 2 300 2 900Maximum flux density (G) 9 500 10 500 12 000(T) 0.95 1.05 1.20Residual 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
40、 (psi) 19 000 28 000 37 500(MPa) 130 190 259Percent elongation in 1 in. (25.4 mm) 8 12 17Apparent 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
41、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 50A811034
