1、Designation: A904 09A904 14Standard 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
2、 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 the magnetic properties of 50 nickel-50 iron parts fabricated by powder metallurgy techniques an
3、dis intended for parts that require high magnetic permeability, high electrical resistivity, low coercive field strength, and lowhysteresis loss. It differs from the wrought alloy specification (see Specification A753) because these parts are porous. A numberof magnetic properties such as permeabili
4、ty are proportional to the sintered density.1.2 This specification deals with powder metallurgy parts in the sintered or annealed condition. Should the sintered parts besubjected to any secondary operation that causes mechanical strain, such as machining or sizing, they should be resintered oranneal
5、ed.1.3 The values stated in customary (cgs-emu and inch-pound) units are to be regarded separately as standard. The values givenin parentheses are mathematical conversions to SI units, which are provided for information only and are not considered standard.1.4 This standard does not purport to addre
6、ss all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A34/A34M Practice
7、 for Sampling and Procurement Testing of Magnetic MaterialsA340 Terminology of Symbols and Definitions Relating to Magnetic TestingA596/A596M Test Method for Direct-Current Magnetic Properties of Materials Using the Ballistic Method and Ring SpecimensA753 Specification for Wrought Nickel-Iron Soft M
8、agnetic Alloys (UNS K94490, K94840, N14076, N14080)A773/A773M Test Method for dc Magnetic Properties of Materials Using Ring and Permeameter Procedures with dc ElectronicHysteresigraphsB328 Test Method for Density, Oil Content, and Interconnected Porosity of Sintered Metal Structural Parts and Oil-I
9、mpregnatedBearings (Withdrawn 2009)3B962 Test Methods for Density of Compacted or Sintered Powder Metallurgy (PM) Products Using Archimedes PrincipleE1019 Test Methods for Determination of Carbon, Sulfur, Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt Alloys byVarious Combustion and Fusion
10、Techniques3. Terminology3.1 The terms and symbols used in this specification are defined in Terminology A340.4. Ordering Information4.1 Orders for parts conforming to this specification shall include the following information.4.1.1 Reference to this standard and year of issue/revision.4.1.2 Referenc
11、e to an applicable part drawing.4.1.3 Quantity required.1 This specification is under the jurisdiction of ASTM Committee A06 on Magnetic Properties and is the direct responsibility of Subcommittee A06.02 on MaterialSpecifications.Current edition approved Nov. 1, 2009May 1, 2014. Published December 2
12、009May 2014. Originally approved in 1990. Last previous edition approved in 20042009 asA90404.09. DOI: 10.1520/A0904-09.10.1520/A0904-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume in
13、formation, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been
14、 made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.
15、Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.1.4 A critical cross section of the part shall be defined and so indicated on the applicable part drawing. The location of thecritical section is by mutual agreement between the user a
16、nd producer (see 6.2).4.1.5 Magnetic property requirements if they are other than stated in 7.5.4.1.6 Certification of chemical composition or magnetic property evaluation, or both (Sections 5 and 7).4.1.7 Marking and packaging requirements (Section 12).4.1.8 Exceptions to this specification or spec
17、ial requirements such as functional testing as mutually agreed upon by the producerand user.5. Chemical Composition5.1 The chemical composition of the parts shall conform to the requirements prescribed in Table 1.5.2 Determination of metallic constituents shall be by a method acceptable to both prod
18、ucer and user. Analysis of carbon,nitrogen, sulfur, and oxygen shall be done in accordance with Test Methods E1019.6. Sintered Density Requirements6.1 Magnetic and residual induction of powder metallurgy parts strongly depend on density. The density of powder metallurgyparts is determined by the com
19、pressibility of the powder, the compacting pressure, and sintering practice (temperature, time, andatmosphere).6.2 Parts produced in conformance with this specification shall have a minimum sintered density of 6.99 g/cm3 (6990 kg/m3)in the critical section of the part. The critical section shall be
20、defined by agreement between the user and producer.6.3 Sintered density shall be determined in accordance with Test Method B328 (which has been replaced by Test MethodsB962).7. Magnetic Property Requirements7.1 Because of the nature of powder metallurgy parts production, magnetic testing of each lot
21、 is not required by thisspecification. Nevertheless, it is strongly recommended that the user require the producer to conduct periodic magnetic evaluationsand to certify such results. Such magnetic property evaluations shall be conducted in the manner described below.7.2 When requested, each lot of
22、parts should be sintered with at least one and preferably three ring test specimens that complywith the geometric requirements listed in Practice A34/A34M. The ring specimen(s) shall be produced from the same mixed lotof powder used to produce the parts.7.3 The magnetic properties shall be determine
23、d in accordance with Test Methods A596/A596M or A773/A773M.7.4 For the purpose of this specification, only the coercive field strength determined from a maximum applied magnetic fieldstrength of 15 Oe (1200 A/m) needs to be determined. Other magnetic properties may be specified by mutual agreement b
24、etweenthe user and producer.7.5 Coercive Field Strength RequirementsParts supplied to this specification shall exhibit a maximum coercive field strengthof 0.4 Oe (32 A/m).7.6 Since magnetic properties are strongly affected by process conditions, refer to the appendixes for typical values andexplanat
25、ory notes.8. Workmanship, Finish, and Appearance8.1 The parts shall be uniform in composition and uniform in density within critical sections.8.2 If parts are sectioned or fractured, there shall be no readily recognizable defects.TABLE 1 Chemical Composition Requirements(in Weight Percent)Element %N
26、ickel 46 -51Carbon 0.02 maxOxygen 0.10 maxNitrogen 0.01 maxOthersA 0.5 maxIronB balanceA Others refers to trace elements that are to be regarded as incidental and notdeliberate additions.B Iron is the balance by difference. Quantitative analysis of this element is notrequired.A904 1429. Sampling9.1
27、A lot shall consist of parts of the same form and dimensions, produced from a single mixed powder batch and from anunchanged process, without discontinuity in production, and submitted for inspection at one time.9.2 The user and producer shall agree upon the number of specimens for testing.10. Rejec
28、tion and Rehearing10.1 Parts that fail to conform to the requirements of this specification shall be rejected. Rejection should be reported to theproducer promptly and in writing. In case of dissatisfaction with the results of the test, the producer may make claim for arehearing.10.2 The disposition
29、 of rejected parts shall be subject to agreement between the user and producer.11. Certification11.1 When specified in the purchase order or contract, the user shall be furnished certification that samples representing eachlot have either been tested or inspected as directed in this specification an
30、d the requirements have been met.11.2 When specified in the purchase order or contract, a report 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 results of any other tests stipu
31、lated in the purchase order or contract.12. Packaging and Package Marking12.1 Packaging shall be subject to agreement between the user and producer.12.2 Parts furnished under this specification shall be in a container identified by the name or symbol of the parts producer.13. Keywords13.1 50 Ni-50 F
32、e; coercive field strength; powder metallurgyAPPENDIXES(Nonmandatory Information)X1. TYPICAL MAGNETIC PROPERTIESX1.1 Typical dc magnetic properties, based on interlaboratory studies, are listed in Table X1.1. These results were obtained usinga sintering practice of 2300F (1260C) in dry hydrogen or i
33、n vacuum. The influence of sintered density is shown. The dataprovided are for information only and are not requirements in this specification.X1.2 Maximum flux density, residual induction, and coercive field strength are measured from a maximum applied magnetic fieldstrength of 15 Oe (1200 A/m).X2.
34、 HEAT TREATMENT OF MAGNETIC TEST SPECIMENS AND PARTSTABLE 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 0.8
35、5 0.90Coercive Field Strength, Oe 0.3 0.3 0.3(A/m) 24 24 24A904 143X2.1 The magnetic properties within this specification are for as-sintered parts. As such, the magnetic properties may not be atoptimum values especially the relative maximum permeability and coercive field strength.To achieve optimu
36、m properties, the partsneed to be annealed to promote grain growth.X2.2 A general heat treatment to improve magnetic properties is as follows:X2.2.1 Place parts in a sealed retort or equivalent,X2.2.2 Introduce a circulated dry hydrogen atmosphere having an entrance dewpoint dew point of 60F (51C) o
37、r lower,X2.2.3 Heat to a temperature of 2050 to 2160F (1120 to 1180C) and hold for 4 h at temperature, andX2.2.4 Cool to room temperature at a rate not to exceed 200F/h (110C/h).ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item men
38、tionedin 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 any time by the responsible technical committee
39、 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 will receive careful consideration at a meeting
40、 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 ASTM International, 100 Barr Harbor Drive, PO B
41、ox 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); 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/).A904 144
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