ASTM A1086-20

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it 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 version
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Designation: A1086 − 13 A1086 − 20
Standard Specification for
Thin-Gauge Nonoriented Electrical Steel Fully Processed
Types
This standard is issued under the fixed designation A1086; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This specification covers the detailed requirements to which flat-rolled thin-gauge nonoriented fully processed electrical
steel shall conform. Nominal thicknesses included in this specification are 0.004 in. (0.10 mm) to 0.012 in. (0.30 mm).0.10 mm
(0.004 in.) to 0.30 mm (0.012 in.).
1.1.1 Refer to Specification A677 for properties of flat-rolled nonoriented fully processed electrical steel in nominal thicknesses
of 0.014 in. (0.36 mm) to 0.025 in. (0.64 mm).0.36 mm (0.014 in.) to 0.64 mm (0.025 in.).
1.1.2 Refer to Specification A876 for properties of flat-rolled grain-oriented fully processed electrical steel.
1.1.3 Thin-gauge nonoriented electrical steels with a high silicon content (typically 6½ %)6 ⁄2 %) manufactured using silicon
vapor-deposition or similar processes are not included in this specification.
1.2 The steel covered in this specification is produced to specified maximum core loss values and is intended primarily for use
in rotating electrical machinery and other electromagnetic devices operating at moderate to elevated frequencies (100 Hz and
greater). Desirable core loss and permeability characteristics are developed during mill processing; however, lamination
manufacturing processes may adversely affect these mill-produced properties. Additional stress-relief heat treatment by the user
may therefore be helpful in remediating these properties in the manufactured laminations. Stress-relief annealing is discussed
further in Appendix X2.
1.3 These thin-gauge nonoriented fully processed electrical steels are low-carbon, silicon-iron, or silicon-aluminum-iron alloys
typically containing 2.5 to 3.5 % silicon and a small amount of aluminum.
1.4 The values stated in customary (cgs-emu and inch-pound) SI units are to be regarded as standard. The values given in
parentheses are mathematical conversions to SI customary (cgs-emu and inch-pound) units which are provided for information
only and are not considered standard.
1.4.1 There are selected values presented in two units, both of which are in acceptable SI units. These are differentiated by the
3 3
word “or,” as in “g/cm , or, (kg/m ).”
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
A34/A34M Practice for Sampling and Procurement Testing of Magnetic Materials
A340 Terminology of Symbols and Definitions Relating to Magnetic Testing
A343/A343M Test Method for Alternating-Current Magnetic Properties of Materials at Power Frequencies Using Wattmeter-
Ammeter-Voltmeter Method and 25-cm Epstein Test Frame
This specification is under the jurisdiction of ASTM Committee A06 on Magnetic Properties and is the direct responsibility of Subcommittee A06.02 on Material
Specifications.
Current edition approved Aug. 1, 2013June 1, 2020. Published August 2013July 2020. Originally approved in 2013. Last previous edition approved in 2013 as A1086 – 13.
DOI: 10.1520/A1086–13.10.1520/A1086-20.
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 the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A1086 − 20
A348/A348M Test Method for Alternating Current Magnetic Properties of Materials Using the Wattmeter-Ammeter-Voltmeter
Method, 100 to 10 000 Hz and 25-cm Epstein Frame
A664 Practice for Identification of Standard Electrical Steel Grades in ASTM Specifications
A677 Specification for Nonoriented Electrical Steel Fully Processed Types
A700 Guide for Packaging, Marking, and Loading Methods for Steel Products for Shipment
A717/A717M Test Method for Surface Insulation Resistivity of Single-Strip Specimens
A719/A719M Test Method for Lamination Factor of Magnetic Materials
A876 Specification for Flat-Rolled, Grain-Oriented, Silicon-Iron, Electrical Steel, Fully Processed Types
A927/A927M Test Method for Alternating-Current Magnetic Properties of Toroidal Core Specimens Using the Voltmeter-
Ammeter-Wattmeter Method
A937/A937M Test Method for Determining Interlaminar Resistance of Insulating Coatings Using Two Adjacent Test Surfaces
A971/A971M Test Method for Measuring Edge Taper and Crown of Flat-Rolled Electrical Steel Coils
A976 Classification of Insulating Coatings for Electrical Steels by Composition, Relative Insulating Ability and Application
E18 Test Methods for Rockwell Hardness of Metallic Materials
E384 Test Method for Microindentation Hardness of Materials
3. Terminology
3.1 Definitions—See Terminology A340.
4. Classification
4.1 The thin-gauge nonoriented electrical steel types described by this specification are as shown in Table 1.
5. Ordering Information
5.1 Orders for material under this specification shall include as much of the following information as necessary to describe the
desired material adequately:
5.1.1 ASTM specification number.
5.1.2 Core-loss type designation.
A B
TABLE 1 Core-Loss Types and Maximum Specific Core Losses
at a Magnetic Flux Density of 10 kG (1.0 T) for As-Sheared
C
Epstein Specimens
Maximum Core Loss Maximum Core Loss
Thickness
Core-Loss Type at 400 Hz at 1000 Hz
in. (mm)
W/lb (W/kg) W/lb (W/kg)
0.004 (0.10) 10T590 5.90 (13.0) 12.0 (26.4)
0.005 (0.12) 12T610 6.10 (13.5) 15.3 (33.7)
0.006 (0.15) 15T640 6.40 (14.0) 17.4 (38.3)
0.007 (0.18) 18T650 6.50 (14.4) 19.5 (43.0)
0.008 (0.20) 20T680 6.80 (15.0) 22.4 (49.4)
0.009 (0.22) 22T700 7.00 (15.4) 25.0 (55.1)
0.010 (0.25) 25T730 7.30 (16.0) 28.0 (61.7)
0.011 (0.27) 27T770 7.70 (17.0) 30.2 (66.6)
0.012 (0.30) 30T820 8.20 (18.0) 32.8 (72.3)
A B
TABLE 1 Core-Loss Types and Maximum Specific Core Losses
at a Magnetic Flux Density of 1.0 T (10 kG) for As-Sheared
C
Epstein Specimens
Maximum Core Loss Maximum Core Loss
Thickness
Core-Loss Type at 400 Hz at 1000 Hz
mm (in.)
W/kg (W/lb) W/kg (W/lb)
0.10 (0.004) 10T590 13.0 (5.90) 37.5 (17.0)
0.12 (0.005) 12T610 13.5 (6.10) 39.7 (18.0)
0.15 (0.006) 15T640 14.0 (6.40) 43.0 (19.5)
0.18 (0.007) 18T650 14.4 (6.50) 46.0 (21.0)
0.20 (0.008) 20T680 15.0 (6.80) 49.4 (22.4)
0.22 (0.009) 22T700 15.4 (7.00) 55.1 (25.0)
0.25 (0.010) 25T730 16.0 (7.30) 61.7 (28.0)
0.27 (0.011) 27T770 17.0 (7.70) 66.6 (30.2)
0.30 (0.012) 30T820 18.0 (8.20) 72.3 (32.8)
A
See Practice A664
B
The test density shall be the correct ASTM assumed density (in accordance with
13.2) for the chemistry used by the producer to meet the property requirements of
the specification.
C
One half of strips cut parallel to the steel rolling direction, one half of strips cut
perpendicular to the steel rolling direction. Refer to Section 13 for applicable test
methods.
A1086 − 20
5.1.3 Surface coating type.
5.1.4 Thickness, width, and length (if in cut lengths instead of coils).
5.1.5 Total weight of ordered item.
5.1.6 Limitations in coil size or lift weights.
5.1.7 End Use—The user shall disclose as much pertinent information as possible about the intended application to enable the
producer to provide material characteristics most suitable for specific fabricating practices.
5.1.8 Special requirements or exceptions to the provisions of this specification shall be negotiated between the user and the
producer.
6. Manufacture
6.1 Typical Melting and Casting:
6.1.1 These thin-gauge fully processed nonoriented electrical steels may be made by basic-oxygen, electric-furnace, or other
steel making practices.
6.1.2 These thin-gauge fully processed nonoriented electrical steels are characterized by low carbon content, usually less than
0.02 %. The principal alloying element is commonly silicon, but aluminum up to about 0.8 % is sometimes used instead of or in
addition to silicon, depending on mill-processing practice for the desired magnetic grade. Individual producers will often have
different silicon or aluminum contents for a particular grade because of intrinsic mill processing procedures.
6.1.3 Additional alloying elements that may be present depending on mill processing procedures include sulfur, typically less
than 0.025 %, manganese in amounts between 0.10 and 0.40 %, and phosphorus, copper, nickel, chromium, molybdenum,
antimony, and tin in residual amounts.
6.1.4 The producer is not required to report the chemical composition of each lot except when a clear need for such information
has been shown. In such cases, the information to be reported shall be negotiated between the producer and the user.
6.2 Typical Rolling and Annealing—The processing sequence for thin-gauge fully processed, nonoriented electrical steel
comprises hot-rolling, annealing, pickling, cold-rolling, and decarburizing annealing.
6.2.1 Commercial Rerolling—When commercial practice calls for the cold-rolling to finished thickness and the development of
the final annealed and coated condition to take place at a production facility other than the original melting and hot-rolling mill,
this rerolling facility should prepare final test data and certifications as well as package and ship the finished material to the user
in accordance with the requirements for producers stated in this standard.
6.3 When changes in the manufacture of the material are believed to exert possible significant effects upon the user’s fabricating
practices and upon the magnetic performance to be obtained in the specified end use, the producer shall notify the user before
shipment is made so the user has an opportunity to evaluate the effects.
7. Magnetic Properties
7.1 Specific Core Loss—Each core-loss type of electrical steel is identified by the maximum core loss requirements as shown
in Table 1.
7.2 Permeability—The permeability at all magnetic flux density levels shall be as high as possible, consistent with the required
core loss limits that govern the grade. Typical relative peak permeability (μ ) values are given in Appendix X1.
p
7.3 Minimum Magnetic Flux Density—The minimum magnetic flux density of materials at specified magnetic field strengths is
frequently useful to the user. Typical values of minimum magnetic flux density are given in Appendix X1.
7.4 Magnetic Aging—Although steel sold to this specification is considered non-aging, the maximum core loss values of Table
1 are based on tests of freshly sheared specimens. The guarantee of magnetic properties after an aging treatment is subject to
negotiation between the user and the producer. The definition of aging coefficient and the aging treatments usually specified are
given in Terminology A340.
8. Surface Insulation Characteristics
8.1 Unless otherwise specified, thin-gauge fully processed nonoriented electrical steels are supplied with a smooth surface finish
and a thin, tightly adherent surface oxide (coating type C-0 in Classification A976) which has sufficient insulating ability for many
small cores.
8.2 Applied Coatings:
8.2.1 Several types of thin, tightly adherent applied coatings with higher levels of insulating ability, including coating type C-5
in Classification A976 as well as other standard and proprietary coating types are available on thin-gauge fully processed
nonoriented electrical steels. If an applied coating is needed, the user shall specify the coating type.
8.2.2 If the insulating ability of the applied coating is unusually critical to the application, the user shall specify not only the
coating type, but also the test method (either Test Method A717/A717M or Test Method A937/A937M) and test conditions to be
used to evaluate the insulating ability of the coating as well as the corresponding minimum value of insulating ability.
8.2.3 A thinner than usual applied coating may be preferred when the core fabricating practice involves welding or die casting.
In such cases the coating type and characteristics shall be determined by agreement of the user and producer.
A1086 − 20
9. Mechanical Requirements
9.1 Lamination Factor—The lamination factor shall be as high as practicable. It is greatest for thicker gages and when the
surface is smooth, uncoated, and without significant amounts of oxide. Lamination factors can be determined using Test Method
A719/A719M. Typical values of lamination factor are given in Appendix X1.
9.2 Hardness—The hardness of these materials can be determined using Test Methods E18 or Test Method E384. Hardness is
affected by chemistry and by the grain size and microstructure of the final product and may differ between producers. If tests for
hardness are to be included with a production order, the test method or methods to be used and acceptable hardness values shall
be negotiated between the user and the producer.
10. Dimensions and Permissible Variations
10.1 Thickness—Nominal thicknesses of each core-loss type are shown in Table 2.
10.2 Thickness Variations—The average thickness of the material supplied shall be as close as possible to the ordered thickness.
Measurements made with a contacting micrometer at points no closer than 0.375 in. (0.95 mm)0.95 mm (0.375 in.) from the edge
of a sheet or coil of specified width shall not differ from the specified thickness by more than the values (which include taper)
shown in Table 2.
10.3 Taper—The rolling of flat-rolled sheets inherently produces an edge which is thinner than the rest of the sheet. This
characteristic is termed “tapered edge,” “feather,” or gamma and occurs primarily within 1 to 2 in. (25 to 51 mm)25 to 51 mm (1
to 2 in.) from the as-rolled edge of the material. The thickness variation involved in edge taper sometimes is the major portion of
the total overall thickness variation permitted by 10.2. Edge taper is defined and may be measured in accordance with Test Method
A971/A971M; allowable taper as measured along a straight line perpendicular to the mill edge within the first 2 in. (51 mm)51
mm (2 in.) or less from either edge of the ordered width is presented in Table 3. It may be expected that the following limits on
the differences in thickness measured will apply.
TABLE 2 Thickness Tolerances
Nominal Thickness Thickness Tolerance
Core-Loss Type
in. (mm) in. (mm)
10T590 0.004 (0.10) ± 0.0003 (0.008)
12T610 0.005 (0.12) ± 0.0004 (0.010)
15T640 0.006 (0.15) ± 0.0005 (0.013)
18T650 0.007 (0.18) ± 0.0005 (0.013)
20T680 0.008 (0.20) ± 0.0006 (0.015)
22T700 0.009 (0.22) ± 0.0007 (0.018)
25T730 0.010 (0.25) ± 0.0008 (0.020)
27T770 0.011 (0.27) ± 0.0009 (0.023)
30T820 0.012 (0.30) ± 0.0012 (0.030)
TABLE 3 Maximum Taper
Nominal Thickness Maximum Taper
Core-Loss Type
in. (mm) in. (mm)
10T590 0.004 (0.10) 0.0003 (0.008)
12T610 0.005 (0.12) 0.0003 (0.008)
15T640 0.006 (0.15) 0.0004 (0.010)
18T650 0.007 (0.18) 0.0005 (0.013)
20T680 0.008 (0.20) 0.0005 (0.013)
22T700 0.009 (0.22) 0.0006 (0.015)
25T730 0.010 (0.25) 0.0007 (0.018)
27T770 0.011 (0.27) 0.0007 (0.018)
30T820 0.012 (0.30) 0.0008 (0.02)
10.4 Width Tolerances—Maximum deviations from the ordered width shall be as shown in Table 4. Allowable deviations for
widths ˃40 in. (1.0 m)˃1.0 m (40 in.) shall be negotiated between the producer and the user.
TABLE 2 Thickness Tolerances
Nominal Thickness Thickness Tolerance
Core-Loss Type
mm (in.) mm (in.)
10T590 0.10 (0.004) ± 0.008 (0.0003)
12T610 0.12 (0.005) ± 0.010 (0.0004)
15T640 0.15 (0.006) ± 0.013 (0.0005)
18T650 0.18 (0.007) ± 0.013 (0.0005)
20T680 0.20 (0.008) ± 0.015 (0.0006)
22T700 0.22 (0.009) ± 0.018 (0.0007)
25T730 0.25 (0.010) ± 0.020 (0.0008)
27T770 0.27 (0.011) ± 0.0
...