ASTM A848-01(2006)
(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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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 2006)
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 dc Electronic Hysteresigraphs
2.2 Other:
1.1 This specification covers the requirements for wrought
IEC Publication 60404-7 Ed. 1 Method of Measurement of
low-carbon iron having a carbon content of 0.015% or less
theCoercivityofMagneticMaterialsinanOpenMagnetic
with the remainder of the analysis being substantially iron.
Circuit
1.1.1 Two alloy types are covered: Type 1 is a low-
phosphorousgradeandType2containsaphosphorousaddition
3. Ordering Information
to improve machinability.
3.1 Orders to this specification shall include as much of the
1.2 This specification also covers alloys supplied by a
following information as is required to describe the desired
producer or converter in the form and condition suitable for
material:
fabricationintopartswhichwillbesubsequentlyheattreatedto
3.1.1 ASTM specification number and alloy type.
create the desired magnetic characteristics. It covers alloys
3.1.2 Dimensions and Tolerances—The tolerances are to be
suppliedintheformofforgingbillets,hot-rolledproducts,and
mutually agreed upon between the user and the producer.
cold-finished bar, wire, and strip.
3.1.3 Quantity (weight or number of pieces).
1.3 This specification does not cover iron powders capable
3.1.4 Form and condition.
of being processed into magnetic components.
3.1.5 Magnetic property requirements if they are other than
1.4 This specification does not cover flat-rolled, low-carbon
stated herein.
electrical steels.
3.1.6 Certification of chemical analysis or magnetic prop-
1.5 The values stated in customary (cgs-emu and inch-
erty evaluation, or both.
pound) units are to be regarded as standard. The values given
3.1.7 Marking and packaging.
in parentheses are mathematical conversions to SI units which
3.1.8 EndUse—Wheneverpossible,theusershouldspecify
are provided for information only and are not considered
whethertheproductwillbemachined,blankedintoflatpieces,
standard.
blanked and formed, or deep drawn to shape.This information
2. Referenced Documents willhelptheproducerprovidethemostsuitableproductforthe
user’s fabrication practice.
2.1 ASTM Standards:
3.1.9 Exceptions to this specification or special require-
A34/A34M Practice for Sampling and ProcurementTesting
ments.
of Magnetic Materials
A341/A341M Test Method for Direct Current Magnetic
4. Chemical Composition
Properties of Materials Using D-C Permeameters and the
4.1 Alloyssuppliedtothisspecificationshallconformtothe
Ballistic Test Methods
requirements in Table 1. Three of the elements listed in Table
A596/A596M Test Method for Direct-Current Magnetic
1, namely vanadium, titanium, and aluminum, are not required
Properties of Materials Using the Ballistic Method and
but may be added to suppress magnetic aging. If present, they
Ring Specimens
must be analyzed and reported.
A773/A773M Test Method for dc Magnetic Properties of
Materials Using Ring and Permeameter Procedures with
5. Form and Condition
5.1 These two alloys are capable of being produced in a
This specification is under the jurisdiction of ASTM Committee A06 on wide variety of forms and conditions for fabrication into
Magnetic Properties and is the direct responsibility of Subcommittee A06.02 on
magneticcomponents.Thedesiredformandconditionshallbe
Material Specifications.
discussed with the producer to assure receiving the correct
Current edition approved May 1, 2006. Published May 2006. Originally
product. Available forms and conditions are:
approved in 1985. Last previous edition approved in 2001 as A848–01. DOI:
10.1520/A0848-01R06.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
A848 – 01 (2006)
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.
6.3 Heat Treatment—It is recommended that the user
Carbon, max 0.020 0.020
Manganese, max 0.35 0.35
specify the desired heat treatment method to be applied to the
Silicon, max 0.15 0.15
test specimens.
Phosphorous 0.030 max 0.10/0.18
6.3.1 When relay condition is specified, the test specimen
Sulfur, max 0.025 0.025
Chromium, max 0.20 0.20
shall be heat treated in a dry forming gas atmosphere (5 to
Nickel, max 0.15 0.15
15% hydrogen in nitrogen with a dew point less than−40°C)
Vanadium, max 0.10 0.10
at a temperature of 845°C for1hat temperature and cooled at
Titanium, max 0.10 0.10
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
5.1.1 Forging Billet—Hot worked and surface conditioned
choose a heat treatment procedure. Refer to Appendix X3 for
by grinding.
heat treatment recommendations.
5.1.2 Hot-Rolled Product—Hot rolled; hot rolled and acid
6.4 Test Method—Magnetic testing shall be conducted in
cleaned;hotrolledandannealed;hotrolled,annealed,andacid
accordancewithTestMethodsA341/A341M,A596/A596M,or
cleaned; hot rolled and mechanically cleaned; mechanical
A773/A773M or by use of a coercimeter. Under this specifi-
properties as specified.
cation only the coercive field strength (H ) must be measured.
c
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 Relay condition applies to 1 in. (25.4 mm) round
or higher must meet the maximum values listed in Table 2
and less in diameter and certain shapes supplied in the
whenthetestspecimenisheattreatedinaccordancewith6.3.1.
cold-workedconditionhavingupto25%reductioninareaand
6.5.1 When a coercimeter is used, the supplier must be able
capable of meeting Class 2 magnetic property requirements as
todemonstratethatthefluxdensityinthetestspecimenreaches
defined in 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—Cold drawn, annealed, mechanical properties
order must be identified and packaged separately.
as 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
8.1 Where any order fails to meet the requirements of this
and capable of meeting Class 2 magnetic property require-
specification, disposition of the material so designated shall be
ments as defin
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