Designation: B68/B68M − 11

Standard Specification for

1
Seamless Copper Tube, Bright Annealed
This standard is issued under the fixed designation B68/B68M; 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.
This standard has been approved for use by agencies of the Department of Defense.

1. Scope* B251M Specification for General Requirements for Wrought

1.1 This specification establishes the requirements for bright Seamless Copper and Copper-Alloy Tube (Metric)
annealed seamless copper tube suitable for use in refrigeration, B577 Test Methods for Detection of Cuprous Oxide (Hydro-
oil lines, gasoline lines, and so forth, where tube with an gen Embrittlement Susceptibility) in Copper
interior surface essentially free from scale and dirt is required. B601 Classification for Temper Designations for Copper and
1.1.1 Tubes made from any of the following Copper UNS Copper Alloys—Wrought and Cast
No. designations shall be supplied, unless otherwise specified B846 Terminology for Copper and Copper Alloys
in the contract or purchase order: B968/B968M Test Method for Flattening of Copper and
Copper-Alloy Pipe and Tube
Copper UNS No.2 Type of Copper
E3 Guide for Preparation of Metallographic Specimens
C10200 Oxygen-free without residual deoxidants E8/E8M Test Methods for Tension Testing of Metallic Ma-
C10300 Oxygen-free, extra low phosphorus terials
C10800 Oxygen-free, low phosphorus
C12000 Phosphorus deoxidized, low residual phosphorus E29 Practice for Using Significant Digits in Test Data to
C12200 Phosphorus deoxidized, high residual phosphorus Determine Conformance with Specifications
1.2 Units—The values stated in either SI units or inch- E53 Test Method for Determination of Copper in Unalloyed
pound units are to be regarded separately as standard. The Copper by Gravimetry
values stated in each system may not be exact equivalents; E62 Test Methods for Chemical Analysis of Copper and
therefore, each system shall be used independently of the other. Copper Alloys (Photometric Methods) (Withdrawn 2010)4
Combining values from the two systems may result in non- E112 Test Methods for Determining Average Grain Size
conformance with the standard. E243 Practice for Electromagnetic (Eddy-Current) Examina-
tion of Copper and Copper-Alloy Tubes
1.3 This standard does not purport to address all of the
E255 Practice for Sampling Copper and Copper Alloys for
safety concerns, if any, associated with its use. It is the
the Determination of Chemical Composition
responsibility of the user of this standard to establish appro-
E527 Practice for Numbering Metals and Alloys in the
priate safety and health practices and determine the applica-
Unified Numbering System (UNS)
bility of regulatory limitations prior to use.
E2575 Test Method for Determination of Oxygen in Copper
2. Referenced Documents and Copper Alloys
2.1 ASTM Standards:3 3. General Requirements
B153 Test Method for Expansion (Pin Test) of Copper and
Copper-Alloy Pipe and Tubing 3.1 The following sections of Specification B251 or B251M
B251 Specification for General Requirements for Wrought are a part of this specification.
Seamless Copper and Copper-Alloy Tube 3.1.1 Terminology, General,
3.1.2 Material and Manufacture,
3.1.3 Workmanship, Finish, and Appearance,
1
This specification is under the jurisdiction of ASTM Committee B05 on Copper 3.1.4 Significance of Numerical Limits,
and Copper Alloys and is the direct responsibility of Subcommittee B05.04 on Pipe 3.1.5 Inspection,
and Tube.
Current edition approved Feb. 15, 2011. Published March 2011. Originally 3.1.6 Rejection and Rehearing,
approved in 1922. Last previous edition approved in 2002 as B68 – 02. DOI: 3.1.7 Certification,
10.1520/B0068_B0068M-11.
2
3.1.8 Test Reports,
Refer to Practice E527 for explanation of unified numbering system (UNS).
3
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
4
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.

*A Summary of Changes section appears at the end of this standard

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 B68/B68M − 11
3.1.9 Packaging and Package Marking, and 6.2.1 The tube shall be manufactured by such hot- or
3.1.10 Supplementary Requirements. cold-working processes as to produce a homogeneous uniform
3.2 In addition, when a section with an identical title to wrought structure in the finished product. The tube shall be
those referenced in 3.1 appears in this specification, such cold drawn to the finished diameter and wall thickness, and
section may contain requirements which supersede those shall be bright annealed to meet the specified temper.
appearing in Specification B251 or B251M. In case of conflict,
this specification prevails. 7. Chemical Composition
7.1 The material shall conform to the chemical composition
4. Terminology requirements prescribed in Table 1 for the specified copper
4.1 Definitions: [alloy] UNS No. designation specified in the ordering infor-
4.1.1 See Terminology B846 for definitions of terms related mation.
to copper and copper alloys. 7.2 These composition limits do not preclude the presence
4.1.2 bright anneal, n—the surface obtained by annealing of other elements. By agreement between the manufacturer and
under conditions of controlled atmosphere to prevent oxidation the purchaser, limits may be established and analysis required
and to retain the original luster of the product. for unnamed elements.
5. Ordering Information 8. Temper
5.1 Include the following information when placing orders
8.1 The tube shall be furnished in either of two annealed
for products under this specification, as applicable:
tempers as follows:
5.1.1 ASTM designation and year of issue (for example,
Annealed (O) Temper Designation
B68/B68M – 11),
5.1.2 UNS copper number (for example, C10200), O50 (Light annealed)
5.1.3 Temper (Section 8), O60 (Soft annealed)
5.1.4 Dimensions, diameter, and wall thickness (Section 8.1.1 Tempers are defined in Classification B601.
16),
5.1.5 How furnished: straight lengths or coils, 9. Grain Size
5.1.6 Total length, or number of pieces, of each size,
9.1 Tube in the tempers O50 (light annealed) and O60 (soft
5.1.7 Total weight, each size, and
annealed) shall conform to the requirements of Table 2.
5.1.8 When product is purchased for agencies of the U.S.
Government.
10. Mechanical Property Requirements
5.2 The following options are available and shall be speci-
fied at the time of placing the order, when required: 10.1 Tensile Strength:
5.2.1 Electromagnetic (eddy-current) test, 10.1.1 The tube shall have a minimum tensile strength of 30
5.2.2 Embrittlement test, ksi (210 MPa) when tested in accordance with Test Methods
5.2.3 Expansion test, E8/E8M.
5.2.4 Flattening test, 10.2 Elongation:
5.2.5 Certification, and 10.2.1 The tensile elongation of the tube shall be a mini-
5.2.6 Mill test report. mum 40 % (2-in. or 50 mm gage length) when tested in
accordance with Test Methods E8/E8M.
6. Materials and Manufacture
6.1 Materials: 11. Performance Requirements
6.1.1 The material of manufacture shall be billets, bars, or 11.1 Expansion Test:
tube of the Copper UNS No. C10200, C10300, C10800, 11.1.1 When specified in the contract or purchase order, the
C12000, or C12200 and shall be of such soundness as to be outside diameter of the tube furnished shall be capable of being
suitable for processing into the tubular products described. expanded as follows when tested in accordance with Test
6.2 Manufacture: Method B153.

TABLE 1 Chemical Composition

Composition, %
Element Copper UNS No.
A
C10200 C10300 C10800 C12000 C12200
Copper,B min 99.95 ... ... 99.90 99.9
CopperB ... 99.95 99.95 ... ...
+ phosphorus, min
Phosphorus ... 0.001–0.005 0.005–0.012 0.004–0.012 0.015–0.040
A
Oxygen in C10200 shall be 10 ppm max. in accordance with E2575.
B
Silver counting as copper.

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 B68/B68M − 11
TABLE 2 Average Grain Size Requirements 16. Dimensions and Permissible Variations
Temper Grain Size, mm
O50 0.015 to 0.040
16.1 The dimensions and tolerances for product covered by
O60 0.040, min this specification shall be as specified in the following tables
and related paragraphs of Specification B251 or B251M:
16.1.1 Wall Thickness Tolerance—Table 1.
16.1.2 Diameter Tolerances—Table 3.
Outside Diameter, in. (mm) Expansion, %
16.1.3 Length Tolerances—Tables 5 and 6.
16.1.4 Squareness of Cut—Refer to Squareness of Cut
3⁄4 (19) and under 40 section 5.6.
over 3⁄4 (19) 30
16.2 Coils, Length Tolerances—Refer to Table 3, Table 4,
11.1.1.1 The expanded tube shall show no cracks or ruptures
and Table 5 of this specification.
seen through visual inspection without the use of special
equipment or enhancement excepting the use of corrective 17. Workmanship, Finish, and Appearance
lenses.
11.1.2 A flattening test is an optional alternative to the 17.1 Workmanship:
expansion test for annealed tube over 4 in. (100 mm) in 17.1.1 The tube furnished shall be clean, free of dirt, scale,
diameter. and other defects, but blemishes of a nature that do not
interfere with the intended application are acceptable.
11.2 Flattening Test: 17.1.2 The tube shall be bright annealed after the last
11.2.1 When specified in the contract or purchase order, the drawing operation or, when required, after coiling.
tube shall be capable of being flattened in accordance with the
test method described in B968/B968M. 17.2 Finish and Appearance:
17.2.1 The interior and exterior surfaces of the tube shall be
12. Microscopical Examination typical in appearance to that of bright annealed copper.
12.1 Samples of Copper UNS Nos. C10200, C10300, and 18. Sampling
C12000 shall be free of cuprous oxide as determined by
Procedure A of Test Methods B577. When Copper UNS Nos. 18.1 The lot size, portion size, and selection of sample
C10800 or C12200 are supplied, examination is not required. portions shall be as follows:
In case of a dispute, a referee method shall be used in 18.1.1 Lot Size—The lot size shall be 10 000 lb (5000 kg) or
accordance with Procedure C of Test Methods B577. fraction thereof.
18.1.2 Portion Size—Sample portions shall be selected as to
13. Hydrogen Embrittlement be representative of the lot according to the following sched-
ule:
13.1 Samples of Copper UNS Nos. C10200, C12000, and
Number of Sample Portions to Be
C12200 shall be capable of passing the embrittlement test of Number of Pieces in Lot TakenA
Procedure B of Test Methods B577. The actual performance of
this test is not mandatory under the terms of this specification 1 to 50 1
51 to 200 2
unless definitely specified in the ordering information. In case 201 to 1500 3
of a dispute, a referee method shall be used in accordance with Over 1500 0.2 % of the total number of pieces in
Procedure C of Test Methods B577. the lot, but not to exceed 10 pieces
_______________
A
Each sample portion shall be taken from a separate tube.
14. Nondestructive Testing
14.1 Upon agreement between the manufacturer and the 18.1.2.1 In case of tube furnished in coils, a length sufficient
purchaser, each tube up to 31⁄8 in. (80 mm) in outside diameter for all necessary tests shall be cut from each coil selected for
shall be subjected to electromagnetic (eddy-current) test. For testing. The remaining portion of the selected coils shall be
this test, the tube shall be examined in the final drawn or included in the shipment and the permissible variation in length
annealed temper, before coiling or in straight lengths. on such coils shall be waived.
14.2 Electromagnetic (Eddy-Current) Test: 18.2 Chemical Composition:
14.2.1 When examined in accordance with Practice E243,
tubes that do not actuate the signaling device of the testing unit
shall be considered as conforming to the requirements of the TABLE 3 Coil Length Tolerances (Specific Lengths)
test. Tolerances, in., All Plus, for Nominal
Tube Outside Diameter, in. Lengths in Feet
Up to 50, incl Over 50 to 100, incl
15. Purchases for U.S. Government Agencies Up to 2, incl 12 24

15.1 When the contract or purchase order stipulates the Tube Outside Diameter, mm Tolerances, mm, All Plus, for Nominal Lengths,
purchase is for an agency of the U.S. Government, the tubes mm
furnished shall conform to the conditions specified in the Up to 15 000, Incl. Over 15 000 to 30 000,
incl.
Supplementary Requirements of Specification B251 or Up to 50, incl 300 610
B251M.

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 B68/B68M − 11
TABLE 4 Coil Length Tolerances (Mill Lengths) 18.2.4 When samples are taken from the semifinished prod-
(Applicable only full-length pieces) uct, a sample shall be taken to represent each 10 000 lb (5000
Tube Outside Tolerances, %, for Nominal Lengths in Feet kg) or fraction thereof, except that not more than one sample
Diameter, in. Up to 100, incl Over 100 to 2000, incl
Up to 1, incl 5A or 2 ft, whichever is 10A
per piece shall be required.
greater
A
Over 1 to 2, incl 5 or 2 ft, whichever is No tolerances
greater established
19. Number of Tests and Retests
A
Expressed to the nearest 1 ft. 19.1 Tests:
19.1.1 Chemical Composition—Shall be determined as the
Tube Out- Tolerances, %, for Nominal Lengths, mm arithmetic mean of results from at least two replicate determi-
side
Up to 30 000, Over 30 000 to
nations for each specified element.
Diameter,
mm incl 600 000, incl 19.1.2 Tensile, Elongation, and Grain Size—Shall be re-
Up to 25, 5A or 600 mm, 10A ported as the average of results from test specimens and each
incl whichever is
greater specimen must conform to specification requirements.
Over 25 to 5A or 600 mm, No tolerances 19.1.3 Other Tests—At least two specimens shall be pre-
50, incl whichever is established
greater pared for each of the other tests and each must meet test
A
Expressed to the nearest 300 mm.
requirements.
19.2 Retest:
19.2.1 When test results obtained by the purchaser fail to
TABLE 5 Coil Schedule of Mill Lengths with Ends conform to the product specification requirement(s), the manu-
Shortest Maximum Permis- facturer or supplier shall have the option to perform a retest.
Tube Outside Nominal Permissible sible Weights of
Diameter, in. Length, ft Length, % of Ends, % of Lot
19.2.2 Retesting shall be as directed in this specification for
Nominal Length Weight the initial test except for the number of test specimens which
Up to 1, incl up to 100, incl 70A 10 shall be twice that normally required for the test.
Over 1, to 2, incl up to 100, incl 60A 20 19.2.3 Test results for all specimens shall conform to the
Up to 1, incl over 100 to 50 50B
2000, incl
requirement(s) of this specification in retest. Failure to comply
A
shall be cause for lot rejection.
Expressed to the nearest 1 ft.
B
Short pieces shall, at the option of the supplier, be included as follows: up to
10 % of lot weight between 50 ft and one quarter of full length and up to 40 % 20. Specimen Preparation
between one quarter and full length.
20.1 Chemical Composition:
Maximum 20.1.1 Preparation of the analytical specimens for the deter-
Shortest
Tube Outside Nominal Permissible
Permissible mination of chemical composition shall be the responsibility of
Weights of the reporting laboratory.
Diameter, mm Length, mm Length, % of
Ends, % of Lot
Nominal Length
Weight 20.2 Grain Size, Microscopical Examination, and Hydrogen
Up to 25, incl up to 30 000, 70A 10 Embrittlement:
incl
Over 25 to 50, incl up to 30 000, 60A 20
20.2.1 Test specimens shall be prepared in accordance with
incl Guide E3.
Up to 25, incl over 30 000 to 50 50B 20.2.1.1 The surface of the specimen shall approximate a
60 000, incl
A
radial longitudinal section of the tube.
Expressed to the nearest 300 mm.
B
Short pieces shall, at the option of the supplier, be included as follows: up to 20.3 Tensile and Elongation Test:
10 % of lot weight between 15 m and one quarter of full length and up to 40 % 20.3.1 The test specimens shall be of the full section of the
between one quarter and full length.
tube and shall conform to the requirements specified in the
section ’Specimens for Pipe and Tube’ in Test Methods
E8/E8M, unless the limitations of the testing machine pre-
cludes the use of such specimens.
18.2.1 The composite sample shall be prepared from ap- 20.3.2 Test specimens conforming to Specimen No. 1 in
proximate equal weights taken from the sample portions and Fig. 13, of Test Methods E8/E8M are acceptable for use when
prepared in accordance with Practice E255. The minimum a full-section specimen cannot be used.
weight of the composite sample shall be 150 g. 20.4 Expansion (Pin) Test:
18.2.2 The manufacturer shall have the option of sampling 20.4.1 Test specimens shall be prepared in accordance with
at the time castings are poured or from the semifinished Test Method B153.
product. When composition has been determined during the
manufacturing process, sampling of the finished product is not 20.5 Flattening Test:
required. 20.5.1 Test specimens, 4 in. in length, shall be cut from one
18.2.3 When sampled at the time castings are poured, at end of two lengths of tube. No special preparation is required.
least two samples shall be taken, one after the start and one
near the end of the pour, for each group of castings poured 21. Test Methods
simultaneously from the same source of molten metal. 21.1 Chemical Analysis:

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 B68/B68M − 11
21.1.1 In case of disagreement, chemical composition shall following and shall not be larger than +0.001 in. (+ 0.025 mm),
be determined as follows: of the hole diameter specified.
Element Test Method Diameter of Drilled
Tube Outside Diameter, in. Holes, in. Drill Number
Copper E53
Phosphorus E62 1⁄4 to 3⁄4 , incl 0.025 72
Over 3⁄4 to 1, incl 0.031 68
21.1.2 Test method(s) for the determination of element(s) Over 1 to 11⁄4, incl 0.036 64
required by contractual or purchase order agreement shall be as Over 11 ⁄4 to 11⁄2 , incl 0.042 58
agreed upon between the manufacturer or supplier and the Over 11 ⁄2 to 13⁄4 , incl 0.046 56
Over 13 ⁄4 to 2, incl 0.052 55
purchaser.
21.2 The tubes furnished shall conform with the physical Diameter of Drilled
Tube Outside Diameter, mm Holes, mm Drill Number
and mechanical properties and all other requirements of this
specification when tested or examined in accordance with the 6.0 to 19.0, incl 0.635 72
following appropriate test method or practice: Over 19.0 to 25, incl 0.785 68
Over 25 to 32, incl 0.915 64
Test Test Method or Practice Over 32 to 38, incl 1.07 58
Over 38 to 45, incl 1.17 56
Grain size E112 Over 45 to 50, incl 1.322 55
Tensile E8/E8M
Elongation E8/E8M 21.2.5.2 Alternatively, at the option of the manufacturer,
Expansion (pin test) B153 using speed insensitive eddy-current units that are equipped to
Microscopical examination B577
Procedure A
select a fraction of the maximum imbalance signal, the
Hydrogen embrittlement B577 following maximum imbalance signals shall be used:
Procedure B
Standard Tube Size, in. Maximum Percent
Flattening test B968/B968M
Imbalance Signal Magnitude
Electromagnetic (eddy-current) examination E243
Determination of Oxygen E2575
Up to 3⁄8, incl 0.2
21.2.1 Grain Size—In case of dispute, grain size shall be 1⁄2 to 2, incl 0.3
Over 2 to 3, incl 0.4
determined by the intercept method.
21.2.2 Tensile Strength—In case of dispute, tensile strength Standard Tube Size, mm Maximum Percent
shall be determined in accordance with Test Methods E8/E8M. Imbalance Signal Magnitude
21.2.3 Microscopical Examination:
Up to 9, incl 0.2
21.2.3.1 Procedure A shall be followed; however, in case of 13 to 50, incl 0.3
dispute, Procedure C of Test Methods B577 shall be followed. Over 50 to 76, incl 0.4
21.2.4 Hydrogen Embrittlement: 21.2.5.3 Tubes that do not activate the signaling device of
21.2.4.1 Procedure B shall be followed; however, in case of the eddy-current tester shall be considered as conforming to the
dispute, Procedure C of Test Methods B577 shall be followed. requirements of this test. Tubes with discontinuities indicated
21.2.5 Electromagnetic (Eddy-Current) Test—Each tube up by the testing unit shall, at the option of the manufacturer, be
to and including 31⁄8 in. (80 mm) in outside diameter shall be reexamined or retested to determine whether the discontinuity
subjected to an eddy-current test. Testing shall follow the is cause for rejection. Signals that are found to have been
procedures in Practice E243. Tubes shall be passed through an caused by minor mechanical damage, soil, or moisture, shall
eddy-current test unit adjusted to provide information on the not be cause for rejection of the tubes provided the tube
suitability of the tube for the intended application. dimensions are still within prescribed limits and the tube is
21.2.5.1 Either notch or drilled hole standards shall be used. suitable for its intended application.
(a) Notch standards, rounded to the nearest 0.001 in. (0.025 21.2.6 Flattening Test:
mm) shall be 22 % of the wall thickness. The notch depth 21.2.6.1 The specimen shall be slowly flattened by a press
tolerance shall be + 0.0005 in. (+ 0.013 mm). so a gage set at three times the tube wall thickness shall pass
(b) Drilled holes shall be drilled radially through the wall freely over the flattened section of the tube.
using a suitable drill jig that has a bushing to guide the drill,
care being taken to avoid distortion of the tube while drilling. 22. Keywords
The diameter of the drilled hole shall be in accordance with the 22.1 bright annealed; copper tube; seamless tube

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 B68/B68M − 11
SUMMARY OF CHANGES

Committee B05 has identified the location of selected changes to this standard since the last issue (B68 – 02)
that may impact the use of this standard. (Approved Feb. 15, 2011.)

(1) 1.2 Units section was modified. (13) In Section 21.2.5.1.b, the +/- tolerance (“vary”) for drilled
(2) 1.3 Reference to B68M was deleted. hole diameter was changed to a plus tolerance (“not be larger
(3) 4.1.2 The definition for “bright anneal” was changed to than”).
agree with the one found in B846. (14) Section 21.2.5.1.a, similar to Section 21.2.5.1.b above, the
(4) The definition for “capable of” was removed since it is +/- notch depth tolerance was changed to a plus only (+)
found in B846. tolerance.
(5) 6.2.1 “size” was changed to “diameter.” (15) 21.2.5.3 Typo was corrected.
(6) 7.1, 7.2 The wording has been changed to agree with B950 (16) B251/B251M was changed to B251 or B251M in several
A.1, 8.1. places since this is not a combined document.
(7) 10.1.1 MPa value was added. (17) E8 was changed to E8/E8M in several places since it is a
(8) In Section 11.2.1, the text for the flattening test procedure combined document.
was replaced with test method B 968/B 968M.
(18) General Requirements were placed directly below Refer-
(9) 16.1.4 Added section number.
enced Documents.
(10) 16.2 Removed Table 2 from list.
(11) B968/B968M was also added to chart in 21.2.
(12) Test Method E2575 was added to Referenced Documents,
21.2, and Table 1 since oxygen concentration is referenced in
Table 1.

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