ASTM B491/B491M-23

Standard Specification for Aluminum and Aluminum-Alloy Extruded Round Tubes for General-Purpose Applications

ABSTRACT
This specification covers aluminum and aluminum-alloy extruded round tubes either in coils or straight lengths, for general purpose applications such as refrigeration service, gas lines, oil lines, and instrument lines, in the alloys and tempers. Chemical composition: silicon, iron, copper, manganese, magnesium, chromium, zinc, vanadium, titanium, and aluminum. Tubes produced shall be cooled from an elevated temperature shaping process and naturally aged to a substantially stable condition. The specimen shall then undergo tests to check leakage and any evidence of leak shall be a cause for rejection. The ends of tubes in selected tempers shall be capable of being expanded by forcing a steel pin into the tube without signs of cracks, ruptures, or other defects clearly visible by normal vision. The tubes shall be supplied in the mill finish and shall be uniform as defined by the requirements of this specification and shall be commercially sound. Each tube shall be examined to determine conformance to this specification with respect to general quality and identification marking.
SCOPE
1.1 This specification covers aluminum and aluminum-alloy extruded round tubes either in coils or straight lengths, for general purpose applications such as refrigeration service, gas lines, oil lines, and instrument lines, in the alloys (Note 2) and tempers shown in Table 2 [Table 3], in outside diameters of 0.250 in. through 0.750 in. [6.00 mm through 20.00 mm]. For diameters over 0.500 in. through 0.750 in. [over 12.50 mm through 20.00 mm], the diameter and wall-thickness tolerances and eddy-current test parameters, if required, shall be agreed upon by the producer and the purchaser. Only tubes in aluminum 1200-H111 and 1235-H111 are sized after extrusion to minimize ovalness.  
1.2 Alloy and temper designations are in accordance with ANSI H35.1/H35.1(M). The equivalent Unified Numbering System alloy designations are those of Table 1 preceded by A9 (for example, A91050 for aluminum 1050), in accordance with Practice E527.  
Note 1: For extruded tubes see Specifications B221 or B221M, and for drawn tubes for general-purpose applications see Specification B483/B483M.
Note 2: Throughout this specification the term alloy  in the general sense includes aluminum as well as aluminum alloy.
Note 3: For inch-pound orders specify B491; for metric orders specify B491M. Do not mix units.  
1.3 For acceptance criteria for inclusion of new aluminum and aluminum alloys in this specification, see Annex A2.  
1.4 The values stated in either inch-pound or SI units are to be regarded separately as standards. The SI units are shown either in brackets or in separate tables. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from two systems will result in nonconformance with the specification.  
1.5 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.

General Information

• Status: Published
• Publication Date: 31-Oct-2023
• ICS: 23.040.15 - Non-ferrous metal pipes
• Technical Committee: B07 - Light Metals and Alloys
• Drafting Committee: B07.03 - Aluminum Alloy Wrought Products

Relations

• Replaces: ASTM B491/B491M-15 - Standard Specification for Aluminum and Aluminum-Alloy Extruded Round Tubes for General-Purpose Applications
• Effective Date: 01-Nov-2023
• Refers: ASTM B660-23 - Standard Practices for Packaging/Packing of Aluminum and Magnesium Products
• Effective Date: 01-Nov-2023
• Refers: ASTM B660-21 - Standard Practices for Packaging/Packing of Aluminum and Magnesium Products
• Effective Date: 01-Sep-2021
• Referred By: ASTM B881-17 - Standard Terminology Relating to Aluminum- and Magnesium-Alloy Products
• Effective Date: 01-Nov-2023

Overview

ASTM B491/B491M-23 is the standard specification for aluminum and aluminum-alloy extruded round tubes designed for general-purpose applications. Developed by ASTM International, this standard applies to extruded tubes supplied in either coils or straight lengths and covers a range of alloys and tempers. Typical applications include uses in refrigeration, gas and oil lines, and instrument piping, where lightweight, durable, and corrosion-resistant tubing is critical. The specification defines requirements for chemical composition, mechanical properties, dimensional tolerances, performance, and quality assurance to ensure reliable and consistent aluminum tubing for both inch-pound and metric systems.

Key Topics

• Coverage and Scope:
  • Applies to round, extruded aluminum and aluminum-alloy tubes in outside diameters from 0.250 in. to 0.750 in. [6.00 mm to 20.00 mm].
  • Includes tubes in both coils and straight lengths.
  • Addresses alloys and tempers in accordance with ANSI H35.1/H35.1(M), with unified numbering as per ASTM Practice E527.
• Chemical Composition:
  • Specifications for elements such as silicon, iron, copper, manganese, magnesium, chromium, zinc, vanadium, titanium, and aluminum.
  • Ensures conformity to registered composition limits for all relevant alloys.
• Mechanical Properties:
  • Provides minimum tensile and yield strength, and elongation requirements, with reference to specified wall thicknesses and temper conditions.
  • Tubes are required to be substantially stable, having been cooled from an elevated temperature shaping process and naturally aged.
• Testing and Quality Assurance:
  • Mandatory tests may include leak testing, expansion tests for tube ends, and tests for internal cleanliness in selected tempers.
  • All tubes must be free from cracks, ruptures, and other defects.
  • Production quality, marking, and certification approaches are defined for traceability and reliability.
• Dimensional and Tolerance Requirements:
  • Defines precise tolerances for diameter, wall thickness, and length, ensuring compatibility with assembly and end-use requirements.

Applications

Aluminum and aluminum-alloy extruded round tubes covered by ASTM B491/B491M-23 are used widely due to their strength, lightweight properties, and corrosion resistance. Primary industries and uses include:

• Refrigeration: Tubes provide durability and efficient heat transfer for refrigeration and air conditioning systems.
• Gas and Oil Lines: The material's corrosion resistance and integrity make it ideal for conveying gases and fluids in commercial and industrial settings.
• Instrument Lines: Used in precise applications, such as scientific instruments and control systems, where reliability and dimension control are essential.
• General Fluid Delivery: Suitable for general-purpose piping and tubing needs in manufacturing, automotive, and infrastructure.

Related Standards

For comprehensive implementation and accurate specification, the following related standards should be considered alongside ASTM B491/B491M-23:

• ASTM B221 / B221M: Standard Specification for Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes.
• ASTM B483/B483M: Standard Specification for Aluminum and Aluminum-Alloy Drawn Tube and Drawn Pipe.
• ANSI H35.1/H35.1(M): Alloy and Temper Designation Systems for Aluminum.
• ASTM B557/B557M: Methods for Tension Testing Wrought and Cast Aluminum- and Magnesium-Alloy Products.
• ASTM B660: Practices for Packaging/Packing of Aluminum and Magnesium Products.
• ASTM B666/B666M: Practice for Identification Marking of Aluminum and Magnesium Products.
• EN 14242: Aluminium and Aluminium Alloys-Chemical Analysis-Inductively Coupled Plasma Optical Emission Spectral Analysis.

Practical Value

Compliance with ASTM B491/B491M-23 ensures that aluminum round tubes meet stringent industry standards for chemical composition, mechanical performance, and dimensional accuracy. This supports manufacturers and end-users in achieving reliable, safe, and durable installations across a range of general-purpose applications-facilitating quality assurance, project specification, and international trade.

Keywords: ASTM B491, aluminum extruded round tubes, aluminum-alloy tubing, general-purpose applications, mechanical properties, chemical composition, dimensional tolerances, refrigeration tubing, gas lines, oil lines, instrument tubing.

Standards Content (Sample)

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: B491/B491M − 23
Standard Specification for
Aluminum and Aluminum-Alloy Extruded Round Tubes for
General-Purpose Applications
This standard is issued under the fixed designation B491/B491M; 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* ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.1 This specification covers aluminum and aluminum-alloy
mendations issued by the World Trade Organization Technical
extruded round tubes either in coils or straight lengths, for
Barriers to Trade (TBT) Committee.
general purpose applications such as refrigeration service, gas
lines, oil lines, and instrument lines, in the alloys (Note 2) and
2. Referenced Documents
tempers shown in Table 2 [Table 3], in outside diameters of
2.1 The following documents of the issue in effect on the
0.250 in. through 0.750 in. [6.00 mm through 20.00 mm]. For
date of material purchase form a part of this specification to the
diameters over 0.500 in. through 0.750 in. [over 12.50 mm
extent referenced herein:
through 20.00 mm], the diameter and wall-thickness tolerances
and eddy-current test parameters, if required, shall be agreed
2.2 ASTM Standards:
upon by the producer and the purchaser. Only tubes in
B221 Specification for Aluminum and Aluminum-Alloy Ex-
aluminum 1200-H111 and 1235-H111 are sized after extrusion
truded Bars, Rods, Wire, Profiles, and Tubes
to minimize ovalness.
B221M Specification for Aluminum and Aluminum-Alloy
Extruded Bars, Rods, Wire, Profiles, and Tubes (Metric)
1.2 Alloy and temper designations are in accordance with
B483/B483M Specification for Aluminum and Aluminum-
ANSI H35.1/H35.1(M). The equivalent Unified Numbering
Alloy Drawn Tube and Drawn Pipe for General Purpose
System alloy designations are those of Table 1 preceded by A9
Applications
(for example, A91050 for aluminum 1050), in accordance with
B557 Test Methods for Tension Testing Wrought and Cast
Practice E527.
Aluminum- and Magnesium-Alloy Products
NOTE 1—For extruded tubes see Specifications B221 or B221M, and
B557M Test Methods for Tension Testing Wrought and Cast
for drawn tubes for general-purpose applications see Specification B483/
Aluminum- and Magnesium-Alloy Products (Metric)
B483M.
NOTE 2—Throughout this specification the term alloy in the general B660 Practices for Packaging/Packing of Aluminum and
sense includes aluminum as well as aluminum alloy.
Magnesium Products
NOTE 3—For inch-pound orders specify B491; for metric orders specify
B666/B666M Practice for Identification Marking of Alumi-
B491M. Do not mix units.
num and Magnesium Products
1.3 For acceptance criteria for inclusion of new aluminum
B881 Terminology Relating to Aluminum- and Magnesium-
and aluminum alloys in this specification, see Annex A2.
Alloy Products
B945 Practice for Aluminum Alloy Extrusions Press Cooled
1.4 The values stated in either inch-pound or SI units are to
from an Elevated Temperature Shaping Process for Pro-
be regarded separately as standards. The SI units are shown
duction of T1, T2, T5 and T10-Type Tempers
either in brackets or in separate tables. The values stated in
B985 Practice for Sampling Aluminum Ingots, Billets, Cast-
each system are not exact equivalents; therefore, each system
ings and Finished or Semi-Finished Wrought Aluminum
must be used independently of the other. Combining values
Products for Compositional Analysis
from two systems will result in nonconformance with the
E29 Practice for Using Significant Digits in Test Data to
specification.
Determine Conformance with Specifications
1.5 This international standard was developed in accor-
E215 Practice for Standardizing Equipment and Electromag-
dance with internationally recognized principles on standard-
netic Examination of Seamless Aluminum-Alloy Tube
This specification is under the jurisdiction of ASTM Committee B07 on Light
Metals and Alloys and is the direct responsibility of Subcommittee B07.03 on
Aluminum Alloy Wrought Products. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2023. Published December 2023. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1969. Last previous edition approved in 2015 as B491/B491M – 15. Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/B0491_B0491M-23. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B491/B491M − 23
E527 Practice for Numbering Metals and Alloys in the 4.2.1 Whether testing for leaks is required (Section 10), and
Unified Numbering System (UNS) frequency of testing required,
E716 Practices for Sampling and Sample Preparation of 4.2.2 For aluminum 1200-H111 and 1235-H111, whether
Aluminum and Aluminum Alloys for Determination of inside cleanliness test is required (11.2), and frequency of
Chemical Composition by Spark Atomic Emission Spec- testing required,
trometry 4.2.3 Whether inspection or witness of inspection and tests
E1251 Test Method for Analysis of Aluminum and Alumi- by the purchaser’s representative is required prior to material
num Alloys by Spark Atomic Emission Spectrometry shipment (Section 14),
4.2.4 Whether certification is required (Section 16),
2.3 ANSI Standards:
4.2.5 Whether marking for identification is required (Sec-
H35.1/H35.1(M) Alloy and Temper Designation Systems for
tion 17), and
Aluminum
4.2.6 Whether Practices B660 apply and, if so, the levels of
H35.2 Dimensional Tolerances for Aluminum Mill Products
preservation packaging, and packing required (18.4).
H35.2M Dimensional Tolerances for Aluminum Mill Prod-
ucts (Metric)
5. Manufacture
2.4 Federal Standard:
5.1 The tubes covered by this specification shall be pro-
Fed. Std. No. 123 Marking for Shipment (Civil Agencies)
duced by the hot-extrusion method. The tube ends shall be
2.5 Military Standard:
crimped or otherwise sealed to avoid contamination during
MIL-STD-129 Marking for Shipment and Storage
shipping. When sized tube in aluminum 1200-H111 or 1235-
2.6 CEN Standard:
H111 is required the extruded tube may be lightly cold drawn.
EN 14242 Aluminium and Aluminium Alloys—Chemical
Analysis—Inductively Coupled Plasma Optical Emission
6. Responsibility for Quality Assurance
Spectral Analysis
6.1 Responsibility for Inspection—Unless otherwise speci-
fied in the contract or purchase order, the producer is respon-
3. Terminology
sible for the performance of all inspection and test require-
3.1 Definitions—Refer to Terminology B881.
ments specified herein. Except as otherwise specified in the
3.2 Definitions of Terms Specific to This Standard:
contract or order, the producer may use his own or any other
3.2.1 capable of—The term capable of as used in this
suitable facilities for the performance of the inspection and test
specification means that the test need not be performed by the
requirements specified herein, unless disapproved by the pur-
producer of the material; however, should testing by the
chaser. The purchaser shall have the right to perform any of the
purchaser establish that the material does not meet these
inspections and tests set forth in this specification where such
requirements, the material shall be subject to rejection.
inspections are deemed necessary to assure that material
conforms to prescribed requirements.
4. Ordering Information
6.2 Lot Definition—An inspection lot shall be defined as
4.1 Orders for material to this specification shall include the
follows:
following information:
6.2.1 For heat-treated tempers, an inspection lot shall con-
4.1.1 This specification designation (which includes the
sist of an identifiable quantity of material of the same mill
number, the year, and the revision letter, if applicable),
form, alloy, temper, and nominal dimensions traceable to a
heat-treated lot or lots, and subjected to inspection at one time.
NOTE 4—For inch-pound orders specify B491, for metric orders specify
B491M. Do not mix units.
6.2.2 For nonheat-treated tempers, an inspection lot shall
consist of an identifiable quantity of material of the same mill
4.1.2 Quantity in pieces or pounds [kilograms],
form, alloy, temper, and nominal dimensions subjected to
4.1.3 Alloy (Section 7),
inspection at one time.
4.1.4 Temper (Section 8),
4.1.5 Cross-sectional dimensions (outside diameter and wall
7. Chemical Composition
thickness, or inside diameter and wall thickness),
7.1 Limits—The extrusions shall conform to the chemical
4.1.6 Length, random or specific,
4.1.7 Nominal inside diameter of coils, and weight or composition limits in Table 1. Conformance shall be deter-
mined by the producer, by taking samples in accordance with
maximum outside diameter, if applicable (18.3),
Practices E716 when the ingots are poured and analyzing those
4.2 Additionally, orders for material to this specification
samples in accordance with Test Methods E1251 or EN 14242.
shall include the following information when required by the
At least one sample shall be taken for each group of ingots
purchaser:
poured simultaneously from the same source of molten metal.
If the producer has determined the chemical composition
during pouring of the ingots, they shall not be required to
Available from Aluminum Association, Inc., 1400 Crystal Drive, Suite 430,
Arlington, VA 22202, http://www.aluminum.org.
sample and analyze the finished product.
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
NOTE 5—It is standard practice in the United States aluminum industry
Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098.
Available from European Committee for Standardization (CEN), Avenue to determine conformance to the chemical composition limits prior to
Marnix 17, B-1000, Brussels, Belgium, http://www.cen.eu. further processing of ingots into wrought products. Due to the continuous
B491/B491M − 23
A,B,C,H
TABLE 1 Chemical Composition Limits
Other
Magne- Chro- Vana- Tita- D
Elements
Alloy Silicon Iron Copper Manganese Zinc Aluminum
sium mium dium nium
E
Each Total
G F
1050 0.25 0.40 0.05 0.05 0.05 . 0.05 0.05 0.03 0.03 . 99.50
F
1100 0.95 Si + Fe 0.05–0.20 0.05 . . 0.10 . . 0.05 0.15 99.00
F
1200 1.00 Si + Fe 0.05 0.05 . . 0.10 . 0.05 0.05 0.15 99.00
G F
1235 0.65 Si + Fe 0.05 0.05 0.05 . 0.10 0.05 0.06 0.03 . 99.35
3003 0.6 0.7 0.05–0.20 1.0–1.5 . . 0.10 . . 0.05 0.15 remainder
3102 0.40 0.7 0.10 0.05–0.40 . . 0.30 . 0.10 0.05 0.15 remainder
6063 0.20–0.6 0.35 0.10 0.10 0.45–0.9 0.10 0.10 . 0.10 0.05 0.15 remainder
A
Limits are in percent maximum unless shown as a range or otherwise stated.
B
Analysis shall be made for the elements for which limits are shown in this table.
C
For purposes of determining conformance to these limits, an observed value or a calculated value attained from analysis shall be rounded off 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 listed elements for which no specific limit is shown as well as 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
Other Elements—Total shall be the sum of unspecified metallic elements 0.010 % or more, rounded to the second decimal before determining the sum.
F
The aluminum content shall be calculated by subtracting from 100.00 % the sum of all metallic elements present in amounts of 0.010 % or more each, rounded to the
second decimal before determining the sum.
G
Vanadium 0.05 %, maximum.
H
In case there of a discrepancy in the values listed in Table 1 with those listed in the “International Alloy Designations and Chemical Composition Limits for Wrought
Aluminum and Wrought Aluminum Alloys” (known as the “Teal Sheets”), the composition limits registered with the Aluminum Association and published in the “Teal Sheets”
should be considered the controlling composition. The “Teal Sheets” are available at http://www.aluminum.org/tealsheets.
A,B
TABLE 2 Tensile Property Limits
Yield Strength
Tensile Strength, ksi
Specified Wall Elongation in
Alloy Temper (0.2 % Offset)
Thickness, in. 2 in. min, %
min max
min, ksi
C
1050 H112 0.032–0.050 8.5 14.5 2.5 25
C
D
H112 0.032–0.050 11.0 17.0 3.0 25
C
1200 H111 0.032–0.050 11.0 17.0 9.5 25
H112 0.032–0.050 10.0 16.0 3.0 25
C
1235 H111 0.032–0.050 11.0 . 7.5 30
H112 0.032–0.050 9.0 15.0 3.0 25
C D
3003 H112 0.032–0.050 14.0 20.0 5.0 25
3102 H112 0.032–0.050 11.0 18.0 4.0 25
6063 T1 0.032–0.050 17.0 . 9.0 12
A
The basis for establishment of mechanical property limits is shown in Annex A1.
B
To determine conformance to this specification, each value for tensile strength and for yield strength shall be rounded to the nearest 0.1 ksi and each value for elongation
to the nearest 0.5 %, both in accordance with the rounding method of Practice E29.
C
Tubes in this alloy are also available in the F (as extruded) temper. Tensile properties for F temper are not specified or guaranteed.
D
Maximum tensile strength for coils. No maximum limit for extruded lengths.
A,B
TABLE 3 Tensile Property Limits [SI Units]
Yield Strength Elongation
Tensile Strength, MPa
Specified Wall
Alloy Temper (0.2 % Offset) in 50 mm
Thickness, mm
min max
min, MPa min, %
C
1050 H112 0.80–1.30 60 100 15 25
C D
1100 H112 0.80–1.30 75 115 20 25
C
1200 H111 0.80–1.30 75 115 65 25
H112 0.80–1.30 70 110 20 25
C
1235 H111 0.80–1.30 75 . 50 30
H112 0.80–1.30 60 105 20 25
C D
3003 H112 0.80–1.30 95 140 35 25
3102 H112 0.80–1.30 95 125 30 25
6063 T1 0.80–1.30 115 . 60 12
A
The basis for establishment of mechanical property limits is shown in Annex A1.
B
To determine conformance to this specification, each value for tensile strength and for yield strength shall be rounded to the nearest 1 MPa and each value for elongation
to the nearest 0.5 %, both in accordance with the rounding method of Practice E29.
C
Tubes in this alloy are also available in the F (as extruded) temper. Tensile properties for F temper are not specified or guaranteed.
D
Maximum tensile strength for coils. No maximum limit for extruded lengths.
B491/B491M − 23
nature of the process, it is not practical to keep a specific ingot analysis
eter) drill holes shall be used to standardize the equipment.
identified with a specific quantity of finished material.
Tubes that produce eddy-current indications less than those
7.2 If it becomes necessary to analyze the fi
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
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
of the standard as published by ASTM is to be considered the official document.
Designation: B491/B491M − 15 B491/B491M − 23
Standard Specification for
Aluminum and Aluminum-Alloy Extruded Round Tubes for
General-Purpose Applications
This standard is issued under the fixed designation B491/B491M; 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 aluminum and aluminum-alloy extruded round tubes either in coils or straight lengths, for general
purpose applications such as refrigeration service, gas lines, oil lines, and instrument lines, in the alloys (Note 2) and tempers
shown in Table 2 [Table 3], in outside diameters of 0.2500.250 in. through 0.750 in. [6.00[6.00 mm through 20.00 mm]. For
diameters over 0.500 through 0.750 in. [over 12.500.500 in. through 0.750 in. [over 12.50 mm through 20.00 mm], the diameter
and wall-thickness tolerances and eddy-current test parameters, if required, shall be agreed upon by the producer and the purchaser.
Only tubes in aluminum 1200-H111 and 1235-H111 are sized after extrusion to minimize ovalness.
1.2 Alloy and temper designations are in accordance with ANSI H35.1/H35.1(M). The equivalent Unified Numbering System
alloy designations are those of Table 1 preceded by A9 (for example, A91050 for aluminum 1050), in accordance with Practice
E527.
NOTE 1—For extruded tubes see SpecificationSpecifications B221 or B221M, and for drawn tubes for general-purpose applications see Specification
B483B483/B483M.
NOTE 2—Throughout this specification the term alloy in the general sense includes aluminum as well as aluminum alloy.
NOTE 3—For inch-pound orders specify B491; for metric orders specify B491M. Do not mix units.
1.3 For acceptance criteria for inclusion of new aluminum and aluminum alloys in this specification, see Annex A2.
1.4 The values stated in either inch-pound or SI units are to be regarded separately as standards. The SI units are shown either
in brackets or in separate tables. The values stated in each system are not exact equivalents; therefore, each system must be used
independently of the other. Combining values from two systems will result in nonconformance with the specification.
1.5 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 The following documents of the issue in effect on the date of material purchase form a part of this specification to the extent
referenced herein:
This specification is under the jurisdiction of ASTM Committee B07 on Light Metals and Alloys and is the direct responsibility of Subcommittee B07.03 on Aluminum
Alloy Wrought Products.
Current edition approved Jan. 1, 2015Nov. 1, 2023. Published January 2015December 2023. Originally approved in 1969. Last previous edition approved in 20062015
as B491/B491M – 06.B491/B491M – 15. DOI: 10.1520/B0491_B0491M-15.10.1520/B0491_B0491M-23.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B491/B491M − 23
2.2 ASTM Standards:
B221 Specification for Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
B221M Specification for Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes (Metric)
B483/B483M Specification for Aluminum and Aluminum-Alloy Drawn Tube and Drawn Pipe for General Purpose Applications
B557 Test Methods for Tension Testing Wrought and Cast Aluminum- and Magnesium-Alloy Products
B557M Test Methods for Tension Testing Wrought and Cast Aluminum- and Magnesium-Alloy Products (Metric)
B660 Practices for Packaging/Packing of Aluminum and Magnesium Products
B666/B666M Practice for Identification Marking of Aluminum and Magnesium Products
B881 Terminology Relating to Aluminum- and Magnesium-Alloy Products
B945 Practice for Aluminum Alloy Extrusions Press Cooled from an Elevated Temperature Shaping Process for Production of
T1, T2, T5 and T10-Type Tempers
B985 Practice for Sampling Aluminum Ingots, Billets, Castings and Finished or Semi-Finished Wrought Aluminum Products for
Compositional Analysis
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E34 Test Methods for Chemical Analysis of Aluminum and Aluminum-Base Alloys (Withdrawn 2017)
E215 Practice for Standardizing Equipment and Electromagnetic Examination of Seamless Aluminum-Alloy Tube
E527 Practice for Numbering Metals and Alloys in the Unified Numbering System (UNS)
E607 Test Method for Atomic Emission Spectrometric Analysis Aluminum Alloys by the Point to Plane Technique Nitrogen
Atmosphere (Withdrawn 2011)
E716 Practices for Sampling and Sample Preparation of Aluminum and Aluminum Alloys for Determination of Chemical
Composition by Spark Atomic Emission Spectrometry
E1251 Test Method for Analysis of Aluminum and Aluminum Alloys by Spark Atomic Emission Spectrometry
2.3 ANSI Standards:
H35.1/H35.1(M) Alloy and Temper Designation Systems for Aluminum
H35.2 Dimensional Tolerances for Aluminum Mill Products
H35.2M Dimensional Tolerances for Aluminum Mill Products (Metric)
2.4 Federal Standard:
Fed. Std. No. 123 Marking for Shipment (Civil Agencies)
2.5 Military Standard:
MIL-STD-129 Marking for Shipment and Storage
2.6 CEN Standard:
EN 14242 Aluminium and Aluminium Alloys—Chemical Analysis—Inductively Coupled Plasma Optical Emission Spectral
Analysis
3. Terminology
3.1 Definitions—Refer to Terminology B881.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 capable of—The term capable of as used in this specification means that the test need not be performed by the producer of
the material. However,material; however, should testing by the purchaser establish that the material does not meet these
requirements, the material shall be subject to rejection.
4. Ordering Information
4.1 Orders for material to this specification shall include the following information:
4.1.1 This specification designation (which includes the number, the year, and the revision letter, if applicable),
NOTE 4—For inch-pound orders specify B491, for metric orders specify B491M. Do not mix units.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from Aluminum Association, Inc., 1525 Wilson Blvd., Suite 600, Arlington, VA 22209,1400 Crystal Drive, Suite 430, Arlington, VA 22202,
http://www.aluminum.org.
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098.
Available from European Committee for Standardization (CEN), Avenue Marnix 17, B-1000, Brussels, Belgium, http://www.cen.eu.
B491/B491M − 23
4.1.2 Quantity in pieces or pounds [kilograms],
4.1.3 Alloy (Section 7),
4.1.4 Temper (Section 8),
4.1.5 Cross-sectional dimensions (outside diameter and wall thickness, or inside diameter and wall thickness),
4.1.6 Length, random or specific,
4.1.7 Nominal inside diameter of coils, and weight or maximum outside diameter, if applicable (18.3),
4.2 Additionally, orders for material to this specification shall include the following information when required by the purchaser:
4.2.1 Whether testing for leaks is required (Section 10), and frequency of testing required,
4.2.2 For aluminum 1200-H111 and 1235-H111, whether inside cleanliness test is required (11.2), and frequency of testing
required,
4.2.3 Whether inspection or witness of inspection and tests by the purchaser’s representative is required prior to material shipment
(Section 14),
4.2.4 Whether certification is required (Section 16),
4.2.5 Whether marking for identification is required (Section 17), and
4.2.6 Whether Practices B660 appliesapply and, if so, the levels of preservation packaging, and packing required (18.4).
5. Manufacture
5.1 The tubes covered by this specification shall be produced by the hot-extrusion method. The tube ends shall be crimped or
otherwise sealed to avoid contamination during shipping. When sized tube in aluminum 1200-H111 or 1235-H111 is required the
extruded tube may be lightly cold drawn.
6. Responsibility for Quality Assurance
6.1 Responsibility for Inspection—Unless otherwise specified in the contract or purchase order, the producer is responsible for the
performance of all inspection and test requirements specified herein. Except as otherwise specified in the contract or order, the
producer may use his own or any other suitable facilities for the performance of the inspection and test requirements specified
herein, unless disapproved by the purchaser. The purchaser shall have the right to perform any of the inspections and tests set forth
in this specification where such inspections are deemed necessary to assure that material conforms to prescribed requirements.
6.2 Lot Definition—An inspection lot shall be defined as follows:
6.2.1 For heat-treated tempers, an inspection lot shall consist of an identifiable quantity of material of the same mill form, alloy,
temper, and nominal dimensions traceable to a heat-treated lot or lots, and subjected to inspection at one time.
6.2.2 For nonheat-treated tempers, an inspection lot shall consist of an identifiable quantity of material of the same mill form,
alloy, temper, and nominal dimensions subjected to inspection at one time.
7. Chemical Composition
7.1 Limits—The extrusions shall conform to the chemical composition limits in Table 1. Conformance shall be determined by the
producer, by taking samples in accordance with Practices E716 when the ingots are poured and analyzing those samples in
accordance with Test Methods E34, E607, E1251, or EN 14242. At least one sample shall be taken for each group of ingots poured
simultaneously from the same source of molten metal. If the producer has determined the chemical composition during pouring
of the ingots, they shall not be required to sample and analyze the finished product.
B491/B491M − 23
A,B,C,H
TABLE 1 Chemical Composition Limits
Other
Magne- Chro- Vana- Tita- D
Elements
Alloy Silicon Iron Copper Manganese Zinc Aluminum
sium mium dium nium
E
Each Total
G F
1050 0.25 0.40 0.05 0.05 0.05 . 0.05 0.05 0.03 0.03 . 99.50
F
1100 0.95 Si + Fe 0.05–0.20 0.05 . . 0.10 . . 0.05 0.15 99.00
F
1200 1.00 Si + Fe 0.05 0.05 . . 0.10 . 0.05 0.05 0.15 99.00
G F
1235 0.65 Si + Fe 0.05 0.05 0.05 . 0.10 0.05 0.06 0.03 . 99.35
3003 0.6 0.7 0.05–0.20 1.0–1.5 . . 0.10 . . 0.05 0.15 remainder
3102 0.40 0.7 0.10 0.05–0.40 . . 0.30 . 0.10 0.05 0.15 remainder
6063 0.20–0.6 0.35 0.10 0.10 0.45–0.9 0.10 0.10 . 0.10 0.05 0.15 remainder
A
Limits are in percent maximum unless shown as a range or otherwise stated.
B
Analysis shall be made for the elements for which limits are shown in this table.
C
For purposes of determining conformance to these limits, an observed value or a calculated value attained from analysis shall be rounded off 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 listed elements for which no specific limit is shown as well as 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
Other Elements—Total shall be the sum of unspecified metallic elements 0.010 % or more, rounded to the second decimal before determining the sum.
F
The aluminum content shall be calculated by subtracting from 100.00 % the sum of all metallic elements present in amounts of 0.010 % or more each, rounded to the
second decimal before determining the sum.
G
Vanadium 0.05%,0.05 %, maximum.
H
In case there of a discrepancy in the values listed in TableTable 1 1 with those listed in the “International Alloy Designations and Chemical Composition Limits for Wrought
Aluminum and Wrought Aluminum Alloys” (known as the “Teal Sheets”), the composition limits registered with the Aluminum Association and published in the “Teal Sheets”
should be considered the controlling composition. The “Teal Sheets” are available at http://www.aluminum.org/tealsheets.
A,B
TABLE 2 Tensile Property Limits
Yield Strength
Tensile Strength, ksi
Specified Wall Elongation in
Alloy Temper (0.2 % Offset)
Thickness, in. 2 in. min, %
min max
min, ksi
C
1050 H112 0.032–0.050 8.5 14.5 2.5 25
C
D
H112 0.032–0.050 11.0 17.0 3.0 25
C
1200 H111 0.032–0.050 11.0 17.0 9.5 25
H112 0.032–0.050 10.0 16.0 3.0 25
C
1235 H111 0.032–0.050 11.0 . 7.5 30
H112 0.032–0.050 9.0 15.0 3.0 25
C D
3003 H112 0.032–0.050 14.0 20.0 5.0 25
3102 H112 0.032–0.050 11.0 18.0 4.0 25
6063 T1 0.032–0.050 17.0 . 9.0 12
A
The basis for establishment of mechanical property limits is shown in Annex A1.
B
To determine conformance to this specification, each value for tensile strength and for yield strength shall be rounded to the nearest 0.1 ksi and each value for elongation
to the nearest 0.5 %, both in accordance with the rounding method of Practice E29.
C
Tubes in this alloy are also available in the F (as extruded) temper. Tensile properties for F temper are not specified or guaranteed.
D
Maximum tensile strength for coils. No maximum limit for extruded lengths.
NOTE 5—It is standard practice in the United States aluminum industry to determine conformance to the chemical composition limits prior to further
processing of ingots into wrought products. Due to the continuous nature of the process, it is not practical to keep a specific ingot analysis identified with
a specific quantity of finished material.
7.2 If it becomes necessary to analyze the finished or semi-finished product for conformance to chemical composition limits, the
methods of sampling and methods of analysis shall be as provided in the following:
7.2.1 Methods of Sampling—Samples for chemical analysis shall be taken in accordance with Practice B985.
7.2.2 Methods of Analysis—Analysis shall be performed in accordance with Test Methods E34, E607, or E1251, or CEN EN 14242
(ICP Method).
7.3 Other methods of analysis or in the case of dispute may be by agreement between the producer and purchaser.
B491/B491M − 23
A,B
TABLE 3 Tensile Property Limits [SI Units]
Yield Strength Elongation
Tensile Strength, MPa
Specified Wall
Alloy Temper (0.2 % Offset) in 50 mm
Thickness, mm
min max
min, MPa min, %
A
1050 H112 0.80–1.30 60 100 15 25
C
1050 H112 0.80–1.30 60 100 15 25
A B
1100 H112 0.80–1.30 75 115 20 25
C D
1100 H112 0.80–1.30 75 115 20 25
A
1200 H111 0.80–1.30 75 115 65 25
C
1200 H111 0.80–1.30 75 115 65 25
H112 0.80–1.30 70 110 20 25
A
1235 H111 0.80–1.30 75 . 50 30
C
1235 H111 0.80–1.30 75 . 50 30
H112 0.80–1.30 60 105 20 25
A B
3003 H112 0.80–1.30 95 140 35 25
C D
3003 H112 0.80–1.30 95 140 35 25
3102 H112 0.80–1.30 95 125 30 25
6063 T1 0.80–1.30 115 . 60 12
A
The basis for establishment of mechanical property limits is shown in Annex A1.
B
To determine conformance to this specification, each value for tensile strength and for yield strength shall be rounded to the nearest 1 MPa and each value for elongation
to the nearest 0.5 %, both in accordance with the rounding method of Practice E29.
C
Tubes in this alloy are also available in the F (as extruded) temper. Tensile properties for F temper are not specified or guaranteed.
D
Maximum tensile strength for coils. No maximum limit for extruded lengths.
8. Tensile Properties
8.1 Limits—Tubes shall conform to the tensile property requirements specified in Table 2 [Table 3].
8.2 Number of Specimens:
8.2.1 One tension test specimen shall be taken for each 1000 lb [500 kg] or fraction thereof in a lot.
8.2.2 Other procedures for selecting samples may be employed if agreed upon by the producer and the purchaser.
8.3 Test Specimens—The tension test specimens shall be as specified in Test Methods B557 [B557M].
8.4 Test Methods—The tension tests shall be made in accordance with Test Methods B557 [B557M].
9. Heat Treatment
9.1 Tubes produced in alloy 6063–T1 shall be cooled from an elevated temperature shaping process and naturally aged to a
substantially stable condition in accordance with Practice B945.
10. Test for Leaks
10.1 When specified by the purchaser at the time of placing the order, tubes shall be tested for leaks by one of the following
methods, at the option of the producer:
10.1.1 Method 1—Tubes shall be tested pneumatically at not less than 60 psig [400 kPa] air pressure while immersed in water or
other suitable liquid. Any evidence of leakage shall be cause for rejection.
10.1.2 Method 2—Tubes shall be tested pneumatically at not less than 90 psig [600 kPa] air pressure with a gauge which will
indicate loss of pressure. There shall not be any loss of pressure during a test period of at least 15-s15 s duration.
10.1.3 Method 3—Tubes of 0.250 through 0.500-in. [6.000.250 in. through 0.500 in. [6.00 mm through 12.50 mm] diameter shall
be subjected to an eddy-current test in accordance with the procedures described in Practice E215. Reference standards or
secondary standards having equivalent eddy-current response shall serve to define acceptance-rejection limits. For tubes over
B491/B491M − 23
0.5000.500 in. through 0.750 in. [over 12.5012.50 mm through 20.00 mm] in diameter eddy-current test parameters, if required,
shall be agreed upon between the producer and the purchaser.
10.1.3.1 For coiled tube, secondary standards having an equivalent eddy-current response to No. 70 (0.028-in. [0.70-
mm](0.028 in. [0.70
...