1、Designation: A904 09Standard Specification for50 Nickel-50 Iron Powder Metallurgy Soft Magnetic Parts1This standard is issued under the fixed designation A904; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. 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 the magnetic properties of 50nickel-50 iron parts fabricated by powder metallurgy tech-niques and is in
3、tended for parts that require high magneticpermeability, high electrical resistivity, low coercive fieldstrength, and low hysteresis loss. It differs from the wroughtalloy specification (see SpecificationA753) because these partsare porous. A number of magnetic properties such as perme-ability are p
4、roportional to the sintered density.1.2 This specification deals with powder metallurgy parts inthe sintered or annealed condition. Should the sintered parts besubjected to any secondary operation that causes mechanicalstrain, such as machining or sizing, they should be resintered orannealed.1.3 The
5、 values stated in customary (cgs-emu and inch-pound) units are to be regarded separately as standard. Thevalues given in parentheses are mathematical conversions to SIunits, which are provided for information only and are notconsidered standard.2. Referenced Documents2.1 ASTM Standards:2A34/A34M Pra
6、ctice for Sampling and Procurement Testingof Magnetic MaterialsA340 Terminology of Symbols and Definitions Relating toMagnetic TestingA596/A596M Test Method for Direct-Current MagneticProperties of Materials Using the Ballistic Method andRing SpecimensA753 Specification for Wrought Nickel-Iron Soft
7、MagneticAlloys (UNS K94490, K94840, N14076, N14080)A773/A773M Test Method for dc Magnetic Properties ofMaterials Using Ring and Permeameter Procedures withdc Electronic HysteresigraphsB328 Test Method for Density, Oil Content, and Intercon-nected Porosity of Sintered Metal Structural Parts andOil-Im
8、pregnated Bearings3B962 Test Methods for Density of Compacted or SinteredPowder Metallurgy (PM) Products Using ArchimedesPrincipleE1019 Test Methods for Determination of Carbon, Sulfur,Nitrogen, and Oxygen in Steel, Iron, Nickel, and CobaltAlloys by Various Combustion and Fusion Techniques3. Termino
9、logy3.1 The terms and symbols used in this specification aredefined in Terminology A340.4. Ordering Information4.1 Orders for parts conforming to this specification shallinclude the following information.4.1.1 Reference to this standard and year of issue/revision.4.1.2 Reference to an applicable par
10、t 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 user andproducer (see 6.2).4.1.5 Magnetic property requirements if they are other thans
11、tated in 7.5.4.1.6 Certification of chemical composition or magneticproperty evaluation, or both (Sections 5 and 7).4.1.7 Marking and packaging requirements (Section 12).4.1.8 Exceptions to this specification or special require-ments such as functional testing as mutually agreed upon bythe producer
12、and user.5. Chemical Composition5.1 The chemical composition of the parts shall conform tothe requirements prescribed in Table 1.5.2 Determination of metallic constituents shall be by amethod acceptable to both producer and user. Analysis of1This specification is under the jurisdiction of ASTM Commi
13、ttee A06 onMagnetic Properties and is the direct responsibility of Subcommittee A06.02 onMaterial Specifications.Current edition approved Nov. 1, 2009. Published December 2009. Originallyapproved in 1990. Last previous edition approved in 2004 as A90404. DOI:10.1520/A0904-09.2For referenced ASTM sta
14、ndards, 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 Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www
15、.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.carbon, nitrogen, sulfur, and oxygen shall be done in accor-dance with Test Methods E1019.6. Sintered Density Requirements6.1 Magnetic and residual induction of powder metallu
16、rgyparts strongly depend on density. The density of powdermetallurgy parts is determined by the compressibility of thepowder, the compacting pressure, and sintering practice (tem-perature, time, and atmosphere).6.2 Parts produced in conformance with this specificationshall have a minimum sintered de
17、nsity of 6.99 g/cm3(6990 kg/m3) in the critical section of the part. The critical section shallbe defined by agreement between the user and producer.6.3 Sintered density shall be determined in accordance withTest Method B328 (which has been replaced by Test MethodsB962).7. Magnetic Property Requirem
18、ents7.1 Because of the nature of powder metallurgy partsproduction, magnetic testing of each lot is not required by thisspecification. Nevertheless, it is strongly recommended that theuser require the producer to conduct periodic magnetic evalu-ations and to certify such results. Such magnetic prope
19、rtyevaluations shall be conducted in the manner described below.7.2 When requested, each lot of parts should be sinteredwith at least one and preferably three ring test specimens thatcomply with the geometric requirements listed in PracticeA34/A34M. The ring specimen(s) shall be produced from thesam
20、e mixed lot of powder used to produce the parts.7.3 The magnetic properties shall be determined in accor-dance with Test Methods A596/A596M or A773/A773M.7.4 For the purpose of this specification, only the coercivefield strength determined from a maximum applied magneticfield strength of 15 Oe (1200
21、 A/m) needs to be determined.Other magnetic properties may be specified by mutual agree-ment between the user and producer.7.5 Coercive Field Strength RequirementsParts suppliedto this specification shall exhibit a maximum coercive fieldstrength of 0.4 Oe (32 A/m).7.6 Since magnetic properties are s
22、trongly affected byprocess conditions, refer to the appendixes for typical valuesand explanatory 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 noreadily r
23、ecognizable 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 user and producer shall agree upon the number
24、 ofspecimens 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 promptly and in writing. In case of dissatisfactionwith the results of the test, the producer may make claim for
25、 arehearing.10.2 The disposition of rejected parts shall be subject toagreement between the user and producer.11. Certification11.1 When specified in the purchase order or contract, theuser shall be furnished certification that samples representingeach lot have either been tested or inspected as dir
26、ected in thisspecification and the requirements have been met.11.2 When specified in the purchase order or contract, areport of the test results shall include:11.2.1 Chemical composition,11.2.2 Part density in the critical section,11.2.3 Magnetic test results, if required by user, and11.2.4 The resu
27、lts of any other tests stipulated in thepurchase order or contract.12. Packaging and Package Marking12.1 Packaging shall be subject to agreement between theuser and producer.12.2 Parts furnished under this specification shall be in acontainer identified by the name or symbol of the partsproducer.13.
28、 Keywords13.1 50 Ni-50 Fe; coercive field strength; powdermetallurgyTABLE 1 Chemical Composition Requirements(in Weight Percent)Element %Nickel 46 -51Carbon 0.02 maxOxygen 0.10 maxNitrogen 0.01 maxOthersA0.5 maxIronBbalanceAOthers refers to trace elements that are to be regarded as incidental and no
29、tdeliberate additions.BIron is the balance by difference. Quantitative analysis of this element is notrequired.A904 092APPENDIXES(Nonmandatory Information)X1. TYPICAL MAGNETIC PROPERTIESX1.1 Typical dc magnetic properties, based on interlabora-tory studies, are listed in Table X1.1. These results we
30、reobtained using a sintering practice of 2300F (1260C) in dryhydrogen or in vacuum. The influence of sintered density isshown. 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 meas
31、ured from a maximum appliedmagnetic field strength of 15 Oe (1200 A/m).X2. HEAT TREATMENT OF MAGNETIC TEST SPECIMENS AND PARTSX2.1 The magnetic properties within this specification arefor as-sintered parts. As such, the magnetic properties may notbe at optimum values especially the relative maximum
32、perme-ability and coercive field strength. To achieve optimum prop-erties, the parts need to be annealed to promote grain growth.X2.2 A general heat treatment to improve magnetic prop-erties is as follows:X2.2.1 Place parts in a sealed retort or equivalent,X2.2.2 Introduce a circulated dry hydrogen
33、atmospherehaving an entrance dewpoint of 60F (51C) or lower,X2.2.3 Heat to a temperature of 2050 to 2160F (1120 to1180C) and hold for4hattemperature, andX2.2.4 Cool to room temperature at a rate not to exceed200F/h (110C/h).ASTM International takes no position respecting the validity of any patent r
34、ights 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.This standard is subject to revision at a
35、ny 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 International Headquarters. Your comments
36、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 shown below.This standard is copyrighted by
37、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), 610-832-9555 (fax), or serviceastm.org (e-mail);
38、 or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).TABLE X1.1 Typical dc Magnetic PropertiesSintered Density,g/cm3(kg/m3)7.0 (7000) 7.3 (7300) 7.5 (7500)Relative MaximumPermeability8100 9400 9900Maximum flux density, G 9000 10000 11000(T) 0.9 1.0 1.1Residual Induction, G 7500 8500 9000(T) 0.75 0.85 0.90Coercive Field Strength, Oe 0.3 0.3 0.3(A/m) 24 24 24A904 093
