ASTM B491/B491M-00 - 10.5.2000
 
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 [2M], in outside diameters of 0.250 through 0.750 in. [6.00 through 20.00 mm]. For diameters over 0.500 through 0.750 in. [over 12.50 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 [H35.1M]. 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 Specification B221, and for drawn tubes for general-purpose applications see Specification B483. 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.

 
2. Referenced Documents

E607-02

Standard Test Method for Atomic Emission Spectrometric Analysis Aluminum Alloys by the Point to Plane Technique Nitrogen Atmosphere

B660-23

Standard Practices for Packaging/Packing of Aluminum and Magnesium Products

B557-15(2023)

Standard Test Methods for Tension Testing Wrought and Cast Aluminum- and Magnesium-Alloy Products

B557M-15(2023)

Standard Test Methods for Tension Testing Wrought and Cast Aluminum- and Magnesium-Alloy Products (Metric)

E34-11

Standard Test Methods for Chemical Analysis of Aluminum and Aluminum-Base Alloys

B666/B666M-20

Standard Practice for Identification Marking of Aluminum and Magnesium Products

B985-24

Standard Practice for Sampling Aluminum Ingots, Billets, Castings and Finished or Semi-Finished Wrought Aluminum Products for Compositional Analysis

E1251-25

Standard Test Method for Analysis of Aluminum and Aluminum Alloys by Spark Atomic Emission Spectrometry

E716-16(2021)e2

Standard Practices for Sampling and Sample Preparation of Aluminum and Aluminum Alloys for Determination of Chemical Composition by Spark Atomic Emission Spectrometry (Includes all amendments and changes 9/7/2022).

E527-23

Standard Practice for Numbering Metals and Alloys in the Unified Numbering System (UNS)

E215-22

Standard Practice for Standardizing Equipment and Electromagnetic Examination of Seamless Aluminum-Alloy Tube

E29-22

Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications

B881-25a

Standard Terminology Relating to Aluminum- and Magnesium-Alloy Products (Includes all amendments and changes 1/8/2026).

B945-21

Standard Practice for Aluminum Alloy Extrusions Press Cooled from an Elevated Temperature Shaping Process for Production of T1, T2, T5 and T10-Type Tempers