1、Designation: A1070 16Standard Specification forCast and Sintered Alnico Permanent Magnets1This standard is issued under the fixed designation A1070; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe
2、r 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 technically important, com-mercially available, magnetically hard, cast and sintered per-manent magnets known comm
3、only as Alnico.1.2 Alnico magnets have approximate magnetic propertiesof residual magnetic induction, Br, from 0.52 T (5200 G) to1.35 T (13500 G) and coercivity, HcB, from 38 kA/m (475 Oe)to 175 kA/m (2200 Oe). Their specific magnetic hysteresisbehavior (demagnetization curves) can be characterized
4、usingTest Method A977/A977M.1.3 The values stated in SI units are to be regarded asstandard. The values given in parentheses are mathematicalconversions to customary (cgs-emu and inch-pound) unitswhich are provided for information only and are not consideredstandard.1.4 This standard does not purpor
5、t to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A340
6、Terminology of Symbols and Definitions Relating toMagnetic TestingA977/A977M Test Method for Magnetic Properties of High-Coercivity Permanent Magnet Materials Using Hyster-esigraphs2.2 Other Standards:MMPA Standard No. 0100-00 Standard Specifications forPermanent Magnet Materials3IEC 60404-8-1 Magne
7、tic Materials Part 8: Specifications forIndividual Materials Section 1 Standard Specificationsfor Magnetically Hard Materials43. Terminology3.1 The terms and symbols used in this specification aredefined in Terminology A340, except as noted in 3.2.3.2 Terms that are not defined in Terminology A340 b
8、ut arein common usage and used herein are as follows.3.2.1 Recoil permeability, (rec), is the permeability corre-sponding to the slope of the recoil line. For reference seeincremental, relative, and reversible permeabilities as definedin Terminology A340. In practical use, this is the slope of theno
9、rmal hysteresis loop in the second quadrant and in proximityto the B-axis. The value of recoil permeability is dimension-less. Note that in producers product literature recoil perme-ability is sometimes represented by the symbol r, which isdefined by Terminology A340 as relative permeability.3.2.2 M
10、agnetic characteristics change with temperature.Two key metrics of permanent magnet performance are re-sidual induction, Br, and intrinsic coercive field strength, HcJ.The change in characteristic over a defined and limitedtemperature range can be reversible, that is, non-destructive.This change is
11、represented by values called reversible tempera-ture coefficients. The symbol for reversible temperature coef-ficient of induction is (Br) and for (intrinsic) coercivity is(HcJ). They are expressed in percent change per degreeCelsius, %/C, or the numerically equivalent percent perKelvin, %/K. The ch
12、anges in magnetic characteristics arenon-linear so it is necessary to specify the temperature rangeover which the coefficient applies.3.2.3 The maximum recommended working temperature,Tw, of a permanent magnet is a semi-arbitrary value sometimesassigned by magnet manufacturers to their products. Twi
13、s notnormative. See Appendix X3 for a more complete discussion.4. Classification4.1 The classification of Alnico permanent magnets is givenin Table 1, and Appendix X1, Table X1.1, with cross-referenceto MMPA Standard No. 0100-00 and IEC 60404-8-1.1This specification is under the jurisdiction of ASTM
14、 Committee A06 onMagnetic Properties and is the direct responsibility of Subcommittee A06.02 onMaterial Specifications.Current edition approved Nov. 1, 2016. Published November 2016. DOI:10.1520/A1070-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Se
15、rvice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3MMPA Standard No. 0100-00 is now available from the Permanent MagnetDivision of the SMAA (www.smma.org). It was previously available from TheInternational M
16、agnetics Association (IMA). The IMA had been the successor to theMMPA and both organizations no longer exist.4Available from International Electrotechnical Commission (IEC), 3, rue deVaremb, 1st Floor, P.O. Box 131, CH-1211, Geneva 20, Switzerland, http:/www.iec.ch.Copyright ASTM International, 100
17、Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Ordering Information5.1 Orders for parts conforming to this specification shallinclude the following information:5.1.1 Reference to this specification and year of issue/revision.5.1.2 Reference to an applicable part d
18、rawing.5.1.3 Magnetic property requirements if they are morestringent than the minimum values listed in the tables.5.1.4 Quantity required.5.1.5 The required magnetization state of the providedmaterial (unmagnetized, fully magnetized, magnetized andthermally stabilized, magnetized and then partially
19、demagnetizedsee Appendix X3 for an explanation of terms).This information should appear on the part drawing wheneverpossible.5.1.6 Certification of magnetic property evaluation.5.1.7 Marking and packaging requirements.5.1.8 Exceptions to this specification or special require-ments such as plating, c
20、oating, or functional testing as mutuallyagreed upon by the producer and user.6. Chemical Composition6.1 The general chemical composition of Alnico magnets isaluminum, nickel, and cobalt with selected transition metalsand minor constituents and the balance of the compositionbeing iron. Approximate c
21、hemical compositions for each gradeare listed in Table 1 and are typical but not mandatory.7. Physical and Mechanical Properties7.1 Typical thermal and physical properties are listed inAppendix X2, Table X2.1.TABLE 1 Alnico Magnets: Minimum Magnetic Property RequirementsANOTE 1“.” indicates that the
22、re is no known published data.ASTMDesignationBChemical CompositionCMaximum EnergyProduct(BH)maxResidual InductionBrCoercive FieldStrengthHcBIntrinsic CoerciveField StrengthHcJAl Ni Co Cu Ti kJ/m3(MGOe) mT (G) kA/m (Oe) kA/m (Oe)CAST ISOTROPIC ALNICOAL-CI-9/47 . . . . . 9.0 (1.1) 550 (5500) 44.0 (553
23、) 47.0 (591)AL-CI-10/38 12 25 . 3 . 9.7 (1.2) 665 (6650) 36.3 (456) 37.8 (475)AL-CI-12/55 . . . . . 11.6 (1.5) 630 (6300) 52.0 (653) 55.0 (691)AL-CI-12/44 10 19 13 3 . 12.2 (1.5) 713 (7125) 42.3 (532) 43.8 (551)AL-CI-17/86 . . . . . 17.0 (2.1) 580 (5800) 80.0 (1005) 86.0 (1081)CAST ANISOTROPIC ALNIC
24、OAL-CA-28/61 8 16 24 3 1 27.9 (3.5) 998 (9975) 59.0 (741) 60.5 (760)AL-CA-36/148 . . . . . 36.0 (4.5) 700 (7000) 140.0 (1759) 148.0 (1860)AL-CA-37/49 . . . . . 37.0 (4.6) 1180 (11 800) 48.0 (603) 49.0 (616)AL-CA-38/112 . . . . . 38.0 (4.8) 800 (8000) 110.0 (1382) 112.0 (1407)AL-CA-36/164 8 14 38 3 8
25、 35.8 (4.5) 684 (6840) 143.6 (1805) 164.1 (2062)AL-CA-38/141 7 15 35 4 5 38.0 (4.8) 779 (7790) 124.7 (1568) 140.6 (1767)AL-CA-39/49 8 14 24 3 . 39.4 (5.0) 1216 (12 160) 48.4 (608) 48.8 (613)AL-CA-44/53 . . . . . 44.0 (5.5) 1200 (12 000) 52.0 (653) 53.0 (666)AL-CA-47/51 8 14 24 3 . 46.6 (5.9) 1264 (1
26、2 635) 50.7 (637) 51.0 (641)AL-CA-58/53 . . . . . 58.0 (7.3) 1300 (13 000) 52.0 (653) 53.0 (666)AL-CA-54/56 8 14 24 3 . 53.7 (6.8) 1283 (12 825) 55.9 (703) 56.3 (708)AL-CA-60/112 . . . . . 60.0 (7.5) 900 (9000) 110.0 (1382) 112.0 (1407)AL-CA-65/115 7 15 35 4 5 64.5 (8.1) 1007 (10 070) 113.4 (1425) 1
27、14.5 (1439)AL-CA-72/120 . . . . . 72.0 (9.0) 1050 (10 500) 118.0 (1483) 120.0 (1508)SINTERED ISOTROPIC ALNICOAL-SI-9/47 . . . . . 9.0 (1.1) 550 (5500) 44.0 (553) 47.0 (591)AL-SI-12/55 . . . . . 11.6 (1.5) 630 (6300) 52.0 (653) 55.0 (691)AL-SI-11/43 10 19 13 3 . 10.7 (1.4) 675 (6745) 41.6 (523) 43.1
28、(542)AL-SI-17/86 . . . . . 17.0 (2.1) 580 (5800) 80.0 (1005) 86.0 (1081)SINTERED ANISOTROPIC ALNICOAL-SA-21/62 8 15 24 3 1 20.8 (2.6) 893 (8930) 59.7 (751) 62.0 (779)AL-SA-26/58 . . . . . 26.0 (3.3) 900 (9000) 56.0 (704) 58.0 (729)AL-SA-28/48 8 14 24 3 . 27.9 (3.5) 1036 (10 355) 46.9 (589) 47.6 (599
29、)AL-SA-31/111 . . . . . 31.0 (3.9) 760 (7600) 107.0 (1345) 111.0 (1395)AL-SA-29/128 7 15 35 4 5 28.6 (3.6) 703 (7030) 113.4 (1425) 127.8 (1606)AL-SA-33/150 . . . . . 33.0 (4.1) 650 (6500) 135.0 (1696) 150.0 (1885)AL-SA-34/48 . . . . . 34.0 (4.3) 1120 (11 200) 47.0 (591) 48.0 (603)AL-SA-32/153 7 14 3
30、8 3 8 32.2 (4.1) 637 (6365) 136.1 (1710) 152.7 (1919)AMagnetic properties are minimum for +20 2 C (+68 4 F) and for a fully magnetized specimen.BASTM Designations are of the form MM-TT-XX/YY where:MM = material (AL = Alnico),TT = type of processing and orientation (CI = cast isotropic (non-oriented)
31、, CA = cast anisotropic (oriented), SI = sintered isotropic (non-oriented),SA = sintered anisotropic (oriented),XX = energy product in k/J/m3rounded to the nearest integer, andYY = intrinsic coercivity in kA/m rounded to the nearest integer.CComposition are representative and approximate and are non
32、-mandatory information. The numbers presented here are weight percent.A1070 1627.2 Physical density values are given for information pur-poses only and are not mandatory.7.3 Alnico magnets are used for their magnetic characteris-tics. The end-use application should not rely on them forstructural pur
33、poses due to low tensile and flexural strength.These materials are brittle and can chip or break easily.Magnetic properties may also be affected by physical stress.8. Magnetic Property Requirements8.1 Magnetic properties are listed in Table 1.8.2 The values of essential magnetic properties listed in
34、 thetable are specified minimum values at +20 6 2 C (+68 64 F), determined after magnetizing to saturation in closedmagnetic circuit.8.3 The specified values of magnetic properties are validonly for magnet test specimens with a uniform cross-sectionalong the axis of magnetization. Properties for ani
35、sotropic(magnetically oriented) magnets are measured along the axis ofpreferred orientation.8.4 Because of the nature of permanent magnet production,magnetic testing of each lot is strongly recommended, espe-cially for applications where the magnet performance is closelyspecified. Such magnetic prop
36、erty evaluations shall be con-ducted in the manner described below. Where the magnet shapeis not suitable for magnetic testing, a specimen shall be cutfrom the magnet using appropriate slicing and grindingtechniques, paying attention to any magnetic orientation withinthe magnet.8.4.1 The magnetic pr
37、operties shall be determined in accor-dance with Test Method A977/A977M, or by using a suitable,mutually agreed upon magnetometric method.8.4.2 When magnets are being purchased in the fullymagnetized condition, the testing shall determine the magneticproperties from the as-received magnetization sta
38、te, followedby magnetization to saturation and testing of the magneticproperties from the fully magnetized condition.8.4.3 When magnets are being purchased in the unmagne-tized condition or in an unknown state of magnetization, thetest laboratory shall magnetize the test specimen(s) to satura-tion i
39、n the same orientation as the received specimensindicated direction of magnetization and measure the magneticproperties from this fully magnetized condition.8.4.4 When magnets are being purchased in a calibrated,stabilized, or “knocked-down” condition, magnets should behandled with care to prevent e
40、xposure to externally appliedfields. Refer to Appendix X3 for an explanation of these terms.During testing using Test Method A977/A977M and to avoidchanging the magnetization state of the material prior to test,the measurement should proceed in the second quadrant onlywithout attempting to saturate
41、the magnet specimen.8.4.5 Other test methods may be utilized as agreed tobetween producer and user. Such tests may include open circuitmagnetization Helmholtz test (refer to Appendix X3), fieldstrength measurements in a defined magnetic circuit or mag-netic flux density measurements adjacent to the
42、magnet sur-face.8.4.6 Due to the ease with which the magnetic field ofAlnico magnets can be affected, the producer and user shouldagree on methods to prevent unintended changes from occur-ring. These preventive measures may include the use ofkeepers across the magnet poles, spacing within packaging
43、toprevent like poles from affecting each other, or other agreed-tomethods.9. Workmanship, Finish, and Appearance9.1 Dimensions and tolerances shall be as specified on themagnet drawing and must be agreed upon between the pro-ducer and user.9.2 Porosity and voids are common in Alnico magnets andshall
44、 not in themselves constitute reason for rejection unlessagreed upon between producer and user. Allowable defectsshall be defined and documented in writing as part of theordering or contracting process.9.3 Magnets shall be free of loose chips and surface residuewhich may interfere with assembly or p
45、roper device function.9.4 Chips shall be acceptable if no more than 10 % of anysurface identified as a magnetic pole surface is removed unlessotherwise agreed to by producer and user.9.5 Cracks visible to the naked eye shall not be permittedunless otherwise agreed to by producer and user.10. Samplin
46、g10.1 Unless otherwise agreed to between producer and user,a lot shall consist of parts of the same form and dimensions,produced from a single furnace melt (cast Alnico) or mixedpowder batch or sintering run (sintered Alnico), and from anunchanged process, without discontinuity in production, andsub
47、mitted for inspection at one time.10.2 The producer and user shall agree upon a representa-tive number of specimens for testing. Typically, a suitablenumber of parts, as mutually agreed upon between producerand user, shall be randomly selected from each lot. It isadvisable to test a minimum of two p
48、arts from each lot, andmore if there is reason to suspect that the magnetic propertiesare not uniform throughout the lot.11. Rejection and Rehearing11.1 Parts that fail to conform to the requirements of thisspecification shall be rejected. Rejection should be reported tothe producer promptly and in
49、writing. In case of dissatisfactionwith the results of the test, the producer may make a claim fora rehearing.11.2 The disposition of rejected parts shall be subject toagreement between the producer and user.12. Certification12.1 When specified in the purchase order or contract, theuser shall be furnished certification that samples representingeach lot have been either tested or inspected as directed in thisspecification and that the requirements have been met.12.2 When specified in the purchase order or contract, areport of the test results shall include:A1070
