1、Designation: A848 01 (Reapproved 2011)A848 17Standard Specification forLow-Carbon Magnetic Iron1This standard is issued under the fixed designation A848; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、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 requirements for wrought low-carbon iron typically having a carbon content of 0.015 % or lesswith the rem
3、ainder of the analysis chemical composition being substantially iron.1.1.1 Two alloy types are covered: Type 1 is a low-phosphorous grade and Type 2 contains a phosphorous addition to improvemachinability.1.2 This specification also covers alloys supplied by a producer or converter in the form and c
4、ondition suitable for fabricationinto parts which will be subsequently heat treated to create the desired magnetic characteristics. It covers alloys supplied in theform of forging billets, hot-rolled products, and cold-finished bar, wire, and strip.1.3 This specification does not cover iron powders
5、capable of being processed into magnetic components. Please refer to thefollowing ASTM Standards for information regarding powdered metal materials and magnetic components: Specifications A811,A839, and A904.1.4 This specification does not cover flat-rolled, low-carbon electrical steels. Please refe
6、r to Specification A726 for informationregarding these materials.1.5 The values stated in customary (cgs-emu and inch-pound) SI units are to be regarded as standard. The values given inparentheses are mathematical conversions to SI customary (cgs-emu and inch-pound) units which are provided for info
7、rmationonly and are not considered standard.1.6 This standard does not purport to address 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 regulato
8、rylimitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organizati
9、on Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2A34/A34M Practice for Sampling and Procurement Testing of Magnetic MaterialsA340 Terminology of Symbols and Definitions Relating to Magnetic TestingA341/A341M Test Method for Direct Current Magnetic Properties
10、of Soft Magnetic Materials Using D-C Permeameters and thePoint by Point (Ballistic) Test MethodsA596/A596M Test Method for Direct-Current Magnetic Properties of Materials Using the Ballistic Method and Ring SpecimensA726 Specification for Cold-Rolled Magnetic Lamination Quality Steel, Semiprocessed
11、TypesA773/A773M Test Method for Direct Current Magnetic Properties of Low Coercivity Magnetic Materials Using Hysteresig-raphsA811 Specification for Soft Magnetic Iron Parts Fabricated by Powder Metallurgy TechniquesA839 Specification for Iron-Phosphorus Powder Metallurgy Parts for Soft Magnetic App
12、licationsA904 Specification for 50 Nickel-50 Iron Powder Metallurgy Soft Magnetic Parts1 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 May 1, 2011Apr
13、il 1, 2017. Published May 2011May 2017. Originally approved in 1985. Last previous edition approved in 20062011 asA848 01 (2011). (2006). DOI: 10.1520/A0848-01R11.10.1520/A0848-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org.
14、 For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.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 made to the previous version. Becauseit ma
15、y 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.Copyright ASTM International, 100 Barr Harb
16、or Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.2 Other:IEC Publication 60404-7 Ed. 1 Magnetic Materials Part 7: Method of Measurement of the Coercivity of Magnetic Materialsin an Open Magnetic Circuit33. Terminology3.1 The terms and symbols used in this specification, unles
17、s otherwise noted, are defined in Terminology A340.4. Ordering Information4.1 Orders to this specification shall include as much of the following information as is required to describe the desired material:4.1.1 ASTM specification number and alloy type.4.1.2 Dimensions and TolerancesTheDimensional t
18、olerances are to be mutually agreed upon between the user and theproducer.4.1.3 Quantity (weight or number of pieces).4.1.4 Form and condition.4.1.5 Magnetic property requirements if they are other than stated herein.4.1.6 Certification of chemical analysis or magnetic property evaluation, or both.4
19、.1.7 Marking and packaging.4.1.8 End UseWhenever possible, the user should specify whether the product will be machined, blanked into flat pieces,blanked and formed, or deep drawn to shape. This information will help the producer provide the most suitable product for theusers fabrication practice.4.
20、1.9 Exceptions to this specification or special requirements.5. Chemical Composition5.1 Alloys supplied to this specification shall conform to the alloy percentage requirements in Table 1. Three of the elementslisted in Vanadium, Table 1, namely vanadium, titanium, and aluminum,aluminum are not requ
21、ired but may be added to suppressmagnetic aging. Ifaging; if present, they mustshall be analyzed and reported.reported and shall meet the requirements in Table 1.6. Form and Condition6.1 TheseThe two alloys alloy types are capable of being produced in a wide variety of forms and conditions for fabri
22、cationinto magnetic components. The desired form and condition shall be discussed with the producer to assure receiving the correctproduct. Available forms and conditions are:6.1.1 Forging BilletHot worked and surface conditioned by grinding.6.1.2 Hot-Rolled ProductHot rolled; hot rolled and acid cl
23、eaned; hot rolled and annealed; hot rolled, annealed, and acidcleaned; hot rolled and mechanically cleaned; mechanical properties as specified.6.1.3 Cold-Finished BarsCold drawn, centerless ground, mechanical properties as specified; or relay condition.6.1.3.1 Relay condition applies to 1 in. (25.4
24、mm) round and Relay condition applies to round bars of 25.4 mm (1.00 in.) orless in diameter and certain other special shapes supplied in the cold-worked condition having up to 25 % reduction in area andcapable of meeting Class 2 magnetic property requirements as defined in 6.57.5.6.1.4 StripCold ro
25、lled, cold rolled and annealed, deep draw quality, mechanical properties as specified; or relay condition.6.1.4.1 Relay condition Relay condition applies to cold-rolled strip 0.020 to 0.200 in. (0.51 to 5.1 mm)0.51 to 5.1 mm (0.020to 0.20 in.) thick having up to 25 % reduction in thickness and capab
26、le of meeting Class 2 magnetic property requirements asdefined in 6.57.5 and Table 2.3 Available from American National Standards Institute, 25 W. 43rd St., 4th Floor, New York, NY 10036.International Electrotechnical Commission (IEC), 3, rue deVaremb, 1st Floor, P.O. Box 131, CH-1211, Geneva 20, Sw
27、itzerland, http:/www.iec.ch.TABLE 1 Chemical Composition Requirements (Weight Percent)Alloy Type 1 Alloy Type 2Carbon, max 0.020 0.020Manganese, max 0.35 0.35Silicon, max 0.15 0.15Phosphorous 0.030 max 0.10/0.18Phosphorous 0.030 max 0.10 to 0.18Sulfur, max 0.025 0.025Chromium, max 0.20 0.20Nickel, m
28、ax 0.15 0.15Vanadium, max 0.10 0.10Titanium, max 0.10 0.10Aluminum, max 0.10 0.10Iron balance balanceA848 1726.1.4.2 Ordering information for strip must include edge condition and mechanical property requirements.6.1.5 WireCold drawn, annealed, mechanical properties as specified or relay condition.6
29、.1.5.1 Relay condition applies to cold-drawn wire when capable of being supplied having up to 25 % reduction in area andcapable of meeting Class 2 magnetic property requirements as defined in 6.57.5 and Table 2.7. Magnetic Property Requirements7.1 DensityThe density for test purposes is 7.86 gcm3 (7
30、860 kg/m3).7.2 Test SpecimenWhenever possible, The test specimen size and shape shall conform to Practice A34/A34M. Shapes suchas ring laminations, solid rings, Epstein specimens, or straight lengths having a uniform cross section are preferred. If, however,it is impossible to prepare a preferred te
31、st specimen shape from the as-manufactured product, specimen shape and size shall bemutually agreed upon by the user and the producer.7.3 Heat TreatmentIt is recommended that the user specify the desired heat treatment method to be applied to the testspecimens.7.3.1 When relay condition“relay condit
32、ion” is specified, the test specimen shall be heat treated in a dry forming gas atmosphere(5 to 15 % hydrogen in nitrogen with a dew point less than 40C) than 40C (40F) at a temperature of 845C (1550F) for1 hone hour at temperature and cooled at a rate from 55 to 100C/h to 500C 100C per hour (99 to
33、180F per hour) to 500C(930F) and cooled at any rate thereafter.7.3.2 If relay condition“relay condition” is not specified and no heat-treating procedure is specified by the user, the produceris free to choose a heat treatment procedure. Refer to Appendix X3 for heat treatment recommendations.7.4 Tes
34、t MethodMagnetic testing shall be conducted in accordance with Test Methods A341/A341M, A596/A596M, orA773/A773M, or by use of a coercimeter. coercimeter as described in 7.5.1. Under this specification only the coercive field strength(HccB) must be measured.7.5 RequirementsThe coercive field strengt
35、h (Coercive field strength, HccB,) measured from a maximum shall be measuredat a magnetic flux density of 15 kG (1.5 T)1.5 T (15 kG) or higher and must meet not exceed the required maximum values listedin Table 2 when the test specimen is heat treated in accordance with 6.3.17.3.1.7.5.1 When a coerc
36、imeter is used, the supplier must be able to demonstrate that the flux density in the test specimen reachesat least 15 kG (1.5T)1.5T(15 kG) during the magnetization cycle. In addition, the test equipment and method shouldshall conformto those specified in IEC Publication 60404-7.8. Packaging and Mar
37、king8.1 Packaging shall be subject to agreement between the producer and the user.8.2 Material furnished under this specification shall be identified by the name or symbol of the producer, by alloy type, meltnumber, and material size. Each lot appliedsupplied on a given order must be identified and
38、packaged separately.8. Investigation of Claim8.1 Where any order fails to meet the requirements of this specification, disposition of the material so designated shall be subjectto agreement between the user and the producer.9. Rejection and Rehearing9.1 Parts that fail to conform to the requirements
39、 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 a claim for arehearing.9.2 The disposition of rejected parts shall be subject to agreement between the produce
40、r and user.10. Keywords10.1 coercive field strength; magnetic iron; relay steelTABLE 2 Direct Current Coercive Field Strength RequirementsClass 1 0.75 Oe (60 A/m)Class 2 (Relay Condition) 1.0 Oe (80 A/m)Class 3 1.5 Oe (120 A/m)TABLE 2 Maximum Direct Current Coercive Field Strength, HcBClass 1 60 A/m
41、 (0.75 Oe)Class 2 (Relay Condition) 80 A/m (1.0 Oe)Class 3 120 A/m (1.5 Oe)A848 173APPENDIXES(Nonmandatory Information)X1. TYPICAL MAGNETIC PROPERTIESX1.1 Typical magnetic properties of these alloys are shown in Fig. X1.1, Fig. X1.2, and Fig. X1.3, and are listed in Table X1.1.There is no statistica
42、lly significant difference in magnetic properties between Type 1 and Type 2 alloys for a given product size,condition, and heat treatment. The data provided are for information only and are not requirements in this specification. Fig. X1.1,Fig. X1.2, and Fig. X1.3 include supplemental x-axes showing
43、 magnetic field strength in oersteds, Oe, to maintain informationalreferences to these charts in prior versions of this specification.FIG. X1.1 Direct Current Hysteresis Loops for Specimen of Low-Carbon Magnetic Iron Exhibiting Class 1 Behavior. Coercive FieldStrength, HcB, is 0.534 Oe (42.5 A/m)42.
44、5 A/m (0.534 Oe)A848 174FIG. X1.2 Direct Current Hysteresis Loops for Specimen of Low-Carbon Magnetic Iron Exhibiting Class 3 Behavior. Coercive FieldStrength, HcB, is 1.18 Oe (93.9 A/m)93.9 A/m (1.18 Oe)TABLE X1.1 Typical dc Magnetic PropertiesNOTE 1Data for solid ring specimens machined from hot-r
45、olled bar,annealed at 843C (1550F) for 4 hfour hours in wet hydrogen and testedin accordance with Test Method A596/A596M. Residual induction (Br)and coercive field strength (strength, HccB,) are measured from a maxi-mum flux density of 15 kG (1.5 T).1.5 T (15 kG).Maximum relative permeability 9400Re
46、sidual induction 14 400 G (1.44 T)Residual induction 1.44 T (14.4 kG)Coercive field strength 0.85 Oe (68 A/m)Coercive field strength 68 A/m (0.85 Oe)A848 175X2. TYPICAL PHYSICALAND MECHANICALADDITIONAL PROPERTIESX2.1 Typical physical properties other than magnetic are shown in Table X2.1. Typical me
47、chanical properties are shown in TableX2.2. The data provided in these tables are for information only and are not requirements in this specification.X3. HEAT TREATMENT OF LOW-CARBON MAGNETIC IRONX3.1 Magnetic test specimens shall be heat treated in accordance with the procedure listed in 6.3.17.3.1
48、 for qualifying materialto meet this specification.X3.2 Parts fabricated from magnetic iron can be heat treated in several different manners depending on the application and theheat-treating equipment available. General comments regarding the heat treatment procedure are as follows:FIG. X1.3 Direct
49、Current Normal Induction Curves to 50 Oe (4 kA/m)4000 A/m (50 Oe) for Low-Carbon Magnetic Iron Exhibiting Class 1and Class 3 PropertiesTABLE X2.1 Typical Room Temperature Physical PropertiesSpecific gravity 7.86Electrical resistivity 13 cm (130 mm)Electrical resistivity 0.13 m (13 cm)Specific heat 0.108 cal/gC (452 J/kgK)Specific heat 452 J/kgK (0.108 cal/gC)Thermal conductivity 0.175 cal/cmsC (73.2 W/mK)Thermal conductivity 73.2 W/mK (0.175 cal/cmsC)Thermal expansivity (20200C) 12.6 10 6/CThermal expansivity (2
