ASTM A848-01(2011)
(Specification)Standard Specification for Low-Carbon Magnetic Iron
Standard Specification for Low-Carbon Magnetic Iron
ABSTRACT
This specification covers the standard requirements for wrought low-carbon iron having a carbon content of 0.015% or less with the remainder of the analysis being substantially iron. These alloys are not electrical steels such as are described in Specifications A 726 and A 840 but are instead primarily used in dc magnetic applications and are produced in a wide variety of mill forms such as forging billet and cold finished bar and wire as well as strip. Two alloy types are covered: Type 1 is a low-phosphorus grade and Type 2 contains a phosphorus addition to improve machinability. Apart from chemical requirements, alloy produced to this specification must exhibit guaranteed maximum values of coercive field strength when heat treated according to this specification. This specification has several useful appendices dealing with typical magnetic, physical and mechanical properties, heat treatment and magnetic aging.
SCOPE
1.1 This specification covers the requirements for wrought low-carbon iron having a carbon content of 0.015 % or less with the remainder of the analysis 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 improve machinability.
1.2 This specification also covers alloys supplied by a producer or converter in the form and condition suitable for fabrication into parts which will be subsequently heat treated to create the desired magnetic characteristics. It covers alloys supplied in the form of forging billets, hot-rolled products, and cold-finished bar, wire, and strip.
1.3 This specification does not cover iron powders capable of being processed into magnetic components.
1.4 This specification does not cover flat-rolled, low-carbon electrical steels.
1.5 The values stated in customary (cgs-emu and inch-pound) units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units which are provided for information only and are not considered standard.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:A848 −01 (Reapproved 2011)
Standard Specification for
Low-Carbon Magnetic Iron
This standard is issued under the fixed designation A848; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope A773/A773MTest Method for Direct Current Magnetic
Properties of Low Coercivity Magnetic Materials Using
1.1 This specification covers the requirements for wrought
Hysteresigraphs
low-carbon iron having a carbon content of 0.015% or less
2.2 Other:
with the remainder of the analysis being substantially iron.
IEC Publication 60404-7 Ed. 1Method of Measurement of
1.1.1 Two alloy types are covered: Type 1 is a low-
theCoercivityofMagneticMaterialsinanOpenMagnetic
phosphorousgradeandType2containsaphosphorousaddition
Circuit
to improve machinability.
1.2 This specification also covers alloys supplied by a
3. Ordering Information
producer or converter in the form and condition suitable for
3.1 Orders to this specification shall include as much of the
fabricationintopartswhichwillbesubsequentlyheattreatedto
following information as is required to describe the desired
create the desired magnetic characteristics. It covers alloys
material:
suppliedintheformofforgingbillets,hot-rolledproducts,and
3.1.1 ASTM specification number and alloy type.
cold-finished bar, wire, and strip.
3.1.2 Dimensions and Tolerances—The tolerances are to be
1.3 This specification does not cover iron powders capable mutually agreed upon between the user and the producer.
of being processed into magnetic components. 3.1.3 Quantity (weight or number of pieces).
3.1.4 Form and condition.
1.4 This specification does not cover flat-rolled, low-carbon
3.1.5 Magnetic property requirements if they are other than
electrical steels.
stated herein.
1.5 The values stated in customary (cgs-emu and inch-
3.1.6 Certification of chemical analysis or magnetic prop-
pound) units are to be regarded as standard. The values given
erty evaluation, or both.
in parentheses are mathematical conversions to SI units which
3.1.7 Marking and packaging.
are provided for information only and are not considered
3.1.8 EndUse—Whenever possible, the user should specify
standard.
whethertheproductwillbemachined,blankedintoflatpieces,
blanked and formed, or deep drawn to shape.This information
2. Referenced Documents
willhelptheproducerprovidethemostsuitableproductforthe
2.1 ASTM Standards:
user’s fabrication practice.
A34/A34MPractice for Sampling and Procurement Testing
3.1.9 Exceptions to this specification or special require-
of Magnetic Materials
ments.
A341/A341MTest Method for Direct Current Magnetic
Properties of Materials Using D-C Permeameters and the 4. Chemical Composition
Ballistic Test Methods
4.1 Alloyssuppliedtothisspecificationshallconformtothe
A596/A596MTest Method for Direct-Current Magnetic
requirements in Table 1. Three of the elements listed in Table
Properties of Materials Using the Ballistic Method and
1, namely vanadium, titanium, and aluminum, are not required
Ring Specimens
but may be added to suppress magnetic aging. If present, they
must be analyzed and reported.
This specification is under the jurisdiction of ASTM Committee A06 on
5. Form and Condition
Magnetic Properties and is the direct responsibility of Subcommittee A06.02 on
Material Specifications.
5.1 These two alloys are capable of being produced in a
Current edition approved May 1, 2011. Published May 2011. Originally
wide variety of forms and conditions for fabrication into
approved in 1985. Last previous edition approved in 2006 as A848–01 (2006).
DOI: 10.1520/A0848-01R11. magneticcomponents.Thedesiredformandconditionshallbe
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from American National Standards Institute, 25 W. 43rd St., 4th
the ASTM website. Floor, New York, NY 10036.
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A848−01 (2011)
TABLE 1 Chemical Requirements (Weight Percent)
shape from the product, specimen shape and size shall be
Alloy Type 1 Alloy Type 2 mutually agreed upon by the user and the producer.
Carbon, max 0.020 0.020
6.3 Heat Treatment—It is recommended that the user
Manganese, max 0.35 0.35
specify the desired heat treatment method to be applied to the
Silicon, max 0.15 0.15
Phosphorous 0.030 max 0.10/0.18
test specimens.
Sulfur, max 0.025 0.025
6.3.1 When relay condition is specified, the test specimen
Chromium, max 0.20 0.20
shall be heat treated in a dry forming gas atmosphere (5 to
Nickel, max 0.15 0.15
Vanadium, max 0.10 0.10
15% hydrogen in nitrogen with a dew point less than−40°C)
Titanium, max 0.10 0.10
at a temperature of 845°C for1hat temperature and cooled at
Aluminum, max 0.10 0.10
a rate from 55 to 100°C/h to 500°C and cooled at any rate
Iron balance balance
thereafter.
6.3.2 If relay condition is not specified and no heat-treating
procedure is specified by the user, the producer is free to
discussed with the producer to assure receiving the correct
choose a heat treatment procedure. Refer to
Appendix X3 for
product. Available forms and conditions are:
heat treatment recommendations.
5.1.1 Forging Billet—Hot worked and surface conditioned
by grinding.
6.4 Test Method—Magnetic testing shall be conducted in
5.1.2 Hot-Rolled Product—Hot rolled; hot rolled and acid
accordance with Test Methods A341/A341M, A596/A596M,
cleaned;hotrolledandannealed;hotrolled,annealed,andacid
or A773/A773M or by use of a coercimeter. Under this
cleaned; hot rolled and mechanically cleaned; mechanical
specification only the coercive field strength (H ) must be
c
properties as specified.
measured.
5.1.3 Cold-Finished Bars—Cold drawn, centerless ground,
6.5 Requirements—The coercive field strength (H ) mea-
c
mechanical properties as specified; or relay condition.
sured from a maximum magnetic flux density of 15 kG (1.5T)
5.1.3.1 Relayconditionappliesto1in.(25.4mm)roundand
or higher must meet the maximum values listed in Table 2
lessindiameterandcertainshapessuppliedinthecold-worked
whenthetestspecimenisheattreatedinaccordancewith6.3.1.
condition having up to 25% reduction in area and capable of
6.5.1 When a coercimeter is used, the supplier must be able
meeting Class 2 magnetic property requirements as defined in
todemonstratethatthefluxdensityinthetestspecimenreaches
6.5.
at least 15 kG (1.5 T) during the magnetization cycle. In
5.1.4 Strip—Cold rolled, cold rolled and annealed, deep
addition, the test equipment and method should conform to
draw quality, mechanical properties as specified; or relay
those specified in IEC Publication 60404-7.
condition.
5.1.4.1 Relay condition applies to cold-rolled strip 0.020 to
7. Packaging and Marking
0.200 in. (0.51 to 5.1 mm) thick having up to 25% reduction
7.1 Packaging shall be subject to agreement between the
in thickness and capable of meeting Class 2 magnetic property
producer and the user.
requirements as defined in 6.5.
7.2 Material furnished under this specification shall be
5.1.4.2 Ordering information for strip must include edge
identifiedbythenameorsymboloftheproducer,byalloytype,
condition and mechanical property requirements.
melt number, and material size. Each lot applied on a given
5.1.5 Wire—Colddrawn,annealed,mechanicalpropertiesas
order must be identified and packaged separately.
specified or relay condition.
5.1.5.1 Relay condition applies to cold-drawn wire when
8. Investigation of Claim
capable of being supplied having up to 25% reduction in area
and capable of meeting Class 2 magnetic property require- 8.1 Where any order fails to meet the requirements of this
specification, disposition of the material so designated shall be
ments as defined in 6.5.
subject to agreement between the user and the producer.
6. Magnetic Property
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