ASTM B373-19

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.
Designation:B373 −19
Standard Specification for
Aluminum Foil for Capacitors
This standard is issued under the fixed designation B373; 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 B881 Terminology Relating toAluminum- and Magnesium-
Alloy Products
1.1 This specification covers nine thicknesses (0.00017 to
B985 Practice for SamplingAluminum Ingots, Billets, Cast-
0.00050 in. (0.0043 to 0.0127 mm)) of annealed aluminum foil
ings and Finished or Semi-Finished Wrought Aluminum
used in the manufacture of capacitors.
Products for Compositional Analysis
1.2 Foil to be used as anodes in electrolytic capacitors is
E29 Practice for Using Significant Digits in Test Data to
beyond the scope of this specification.
Determine Conformance with Specifications
E252 Test Method for Thickness of Foil, Thin Sheet, and
1.3 Alloy designations are in accordance with ANSI
H35.11/H35.1(M). The equivalent Unified Numbering System Film by Mass Measurement
E345 Test Methods of Tension Testing of Metallic Foil
alloy designations are those of Table 1 preceded by A9, for
example, A91145 for Aluminum 1145 in accordance with E527 Practice for Numbering Metals and Alloys in the
Unified Numbering System (UNS)
Practice E527.
E607 Test Method for Atomic Emission Spectrometric
1.4 For acceptance criteria for inclusion of new aluminum
Analysis Aluminum Alloys by the Point to Plane Tech-
and aluminum alloys in this specification, see Annex A1.
nique Nitrogen Atmosphere (Withdrawn 2011)
1.5 The values stated in inch-pound units are to be regarded
E716 Practices for Sampling and Sample Preparation of
as the standard. The values given in parentheses are for
Aluminum and Aluminum Alloys for Determination of
information only.
Chemical Composition by Spark Atomic Emission Spec-
1.6 This international standard was developed in accor- trometry
dance with internationally recognized principles on standard- E1251 Test Method for Analysis of Aluminum and Alumi-
ization established in the Decision on Principles for the num Alloys by Spark Atomic Emission Spectrometry
Development of International Standards, Guides and Recom- E3061 Test Method for Analysis of Aluminum and Alumi-
mendations issued by the World Trade Organization Technical numAlloys by Inductively Coupled PlasmaAtomic Emis-
Barriers to Trade (TBT) Committee. sion Spectrometry (Performance Based Method)
2.3 ANSI Standard:
2. Referenced Documents
H35.1/H35.1(M) AlloyandTemperDesignationSystemsfor
2.1 The following documents of the issue in effect on the Aluminum
date of material purchase form a part of this specification to the
2.4 Other Standards:
extent referenced herein.
CEN EN 14242 Aluminum and aluminum alloys. Chemical
analysis. Inductively coupled plasma optical emission
2.2 ASTM Standards:
spectral analysis
B193 Test Method for Resistivity of Electrical Conductor
Materials
3. Terminology
B666/B666M Practice for Identification Marking of Alumi-
num and Magnesium Products 3.1 Definitions:
3.1.1 Refer to Terminology B881 for definitions of product
terms used in this specification.
This specification is under the jurisdiction of ASTM Committee B07 on Light
3.2 Definitions of Terms Specific to This Standard:
Metals and Alloys and is the direct responsibility of Subcommittee B07.03 on
Aluminum Alloy Wrought Products.
Current edition approved July 1, 2019. Published July 2019. Originally approved
in 1961. Last previous edition approved in 2006 as B373 – 00 (2006) which was The last approved version of this historical standard is referenced on
withdrawn January 2015 and reinstated in July 2019. DOI: 10.1520/B0373-19. www.astm.org.
2 4
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from Aluminum Association, Inc., 1400 Crystal Drive Suite 430,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Arlington, VA 22202. http://www.aluminum.org.
Standards volume information, refer to the standard’s Document Summary page on Available from European Committee for Standardization, Central Secretariat
the ASTM website. (CEN), rue de Stassart 36, B1050 Brussels, Belgium. www.cen.eu.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B373−19
A,B,C,F
TABLE 1 Chemical Requirements
D
Aluminum Silicon Other Elements
Copper Manganese Magnesium Zinc Vanadium Titanium Aluminum
Designation plus Iron Each Total
E
1235 0.65 0.05 0.05 0.05 0.10 0.05 0.06 0.03 . 99.35 min
E
1145 0.55 0.05 0.05 0.05 0.05 0.05 0.03 0.03 . 99.45 min
A
Limits are in percent maximum unless stated otherwise.
B
Analysis shall be made for the elements for which limits are shown in this table, except Aluminum.
C
For purposes of determining the conformance to these limits, an observed value or a calculated value attained from analysis shall be rounded to the nearest unit in the
last right-hand place of figures used in expressing the specified limit, in accordance with the rounding method of Practice E29.
D
Others includes all unlisted metallic elements. The producer may analyze samples for trace elements not specified in the specification. However, such analysis is not
required and may not cover all metallic Others elements. Should any analysis by the producer or the purchaser establish that an Others element exceeds the limit of Each
or that the aggregate of several Others elements exceeds the limit of Total, the material shall be considered nonconforming.
E
The minimum content shall be calculated by subtracting from 100.00 %, the sum of all metallic elements present in amounts of 0.010 % or more, each roundedtothe
second decimal before determining the sum.
F
In case there is a discrepancy in the values listed in Table 1 with those listed in the “International Alloy Designations and Chemical Composition Limits for Wrought
AluminumandWroughtAluminumAlloys”(knownasthe“TealSheets”),thecompositionlimitsregisteredwiththeAluminumAssociationandpublishedinthe“TealSheets”
shall be considered the controlling composition. The “Teal Sheets” are available at www.aluminum.org.
3.2.1 capable of—The term capable of as used in this 4.2.2 Whether certification is required (Section 18), and
specification means that the test need not be performed by the
4.2.3 Whether marking for identification is required (see
producer of the material. However, should subsequent testing
19.1).
by the purchaser establish that the material does not meet these
requirements, the material shall be subject to rejection.
5. Manufacturing Process Changes
3.2.2 dry annealed A—having a test dryness of 100/0, free
5.1 No process changes shall be made in the manufacture of
from residual rolling oil, as determined by the water test
this material after initially approved by the purchaser, except
(10.2.1).
by prior agreement between the purchaser and the producer.
3.2.3 dry annealed B—having a test dryness of 90/10, a
slight film of residual rolling oil, as determined by the
6. Responsibility for Quality Assurance
wateralcohol test (10.2.2).
6.1 Responsibility for Inspection and Tests—Unless other-
3.2.4 dry annealed C—having a test dryness of 80/20, a
wise specified in the contract or purchase order, the producer is
slight film of residual rolling oil, as determined by the
responsible for the performance of all inspection and test
wateralcohol test (10.2.3).
requirements specified herein. Except as otherwise specified in
3.2.5 slick annealed—having a uniform film of residual the contract or order, the producer may use his own or any
rolling oil or applied oil as determined by the water test other suitable facilities for the performance of the inspection
(10.2.4). and test requirements specified herein, unless disapproved by
the purchaser. The purchaser shall have the right to perform
3.2.6 producer—the primary manufacturer of the material.
any of the inspections and tests set forth in this specification
3.2.7 supplier—includes only the category of jobbers and
where such inspections are deemed necessary to assure that the
distributors as distinct from producers.
material conforms to prescribed requirements.
4. Ordering Information
6.2 Lot Definition—An inspection lot shall consist of an
identifiable quantity of material of the same alloy, temper, and
4.1 Orders for material to this specification shall include the
nominal dimensions subjected to inspection at one time.
following information:
4.1.1 This specification designation (which includes the
7. Chemical Composition
number, the year, and the revision letter, if applicable),
4.1.2 Quantity in pounds,
7.1 Limits—The foil shall conform to the chemical compo-
4.1.3 Aluminum designation (Section 7),
sition limits prescribed in Table 1. Conformance shall be
4.1.4 Nominal thickness and width (Section 11),
determined by the producer by taking samples in accordance
4.1.5 Surface condition (Section 10),
with Practices E716 when the ingots are poured and analyzing
4.1.6 Outside diameter of rolls (Section 13),
those samples in accordance with Test Methods E607, E1251,
4.1.7 Inside diameter of cores (Section 13);
E3061, or EN14242. At least one sample shall be taken for
4.2 Additionally, orders for material to this specification each group of ingots poured simultaneously from the same
shall include the following information when required by the source of molten metal. If the producer of the foil or the
purchaser: producer of the material from which the foil is produced has
4.2.1 Whether inspection or witness of inspection and tests determined the chemical composition of the material during
by the purchaser’s representative is required prior to material pouring of the ingots, they shall not be required to sample and
shipment (Section 16), analyze the finished product.
B373−19
NOTE 1—It is standard practice in the United States aluminum industry NOTE2—Experienceoftestingoffoilhasdemonstratedthatfailuresare
to determine conformance to the chemical composition limits prior to more likely due to faulty test specimens, or to misalignment of the
further processing of ingots into wrought products. Due to the continuous specimen in the testing machine, than is the case with material having a
nature of the process, it is not practical to keep a specific ingot analysis greater section thickness. Care must be exercised to discard test results
identified with a specific quantity of finished material. where the evidence indicates that the specimen failure may be related to
testing conditions.
7.2 If it becomes necessary to analyze foil for conformance
to chemical composition limits, the methods of sampling and
9. Electrical Properties
methods of analysis shall be as provided in the following:
9.1 Electrical Resistance—The foil shall be capable of
7.2.1 Methods of Sampling—Samples for chemical analysis
conforming to the direct current electrical resistance require-
shall be taken in accordance with Practice B985.
ments prescribed in Table 3 when measured at a temperature
7.2.2 Methods of Analysis—Analysis shall be performed in
between 60 and 80 °F (15 and 25 °C).
accordance with E607, E1251, E3061, or EN 14242.
NOTE 3—Direct-current electrical resistance values listed in Table 3 are
7.3 Other methods of analysis or in the case of dispute may
based on a minimum electrical conductivity of 58.5 % IACS and the
be by agreement between the producer and the purchaser.
minimum permissible foil thickness corresponding with each nominal
thickness.
8. Mechanical Properties
9.2 Number of Specimens—When electrical resistance is
8.1 Tensile Breaking Load—The foil shall be capable of
determined, tests shall be made on samples from each 1000 lb
conforming to the tensile breaking load requirements pre-
(454 kg), or fraction thereof, of each thickness and width of
scribed in Table 2. Splices shall be capable of developing 80 %
coil in a lot. Not less than two samples shall be selected with
of the breaking load specified for unspliced foil.
each sample from a different roll of foil except that if the lot
8.2 Number of Specimens—When tensile breaking load is
consists of only one roll of foil, one sample shall be selected.
determined, tests shall be made on samples from each 1000 lb
9.3 Method of Test—When electrical resistance is
(454 kg), or fraction thereof, of each thickness and width of
determined, this determination shall be made by any method
coil in a lot. Not less than two samples shall be selected with
having an accuracy of 60.001Ω, provided that in the case of
each sample from a different roll of foil except that if the lot
dispute, the results obtained by Test Method B193 shall be the
consists of only one roll of foil, one sample shall be selected.
basis for acceptance.
Each sample shall consist of either a single-thickness or
multiple-thickness specimen from one roll of foil.
10. Surface Condition
8.3 Test Method—For determination of tensile breaking
10.1 The foil shall be supplied with the finish bright on one
load, tests shall be made in accordance with Test Methods
side and matte on the other.
E345. If b
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