ASTM A787-00
(Specification)Standard Specification for Electric-Resistance-Welded Metallic-Coated Carbon Steel Mechanical Tubing
Standard Specification for Electric-Resistance-Welded Metallic-Coated Carbon Steel Mechanical Tubing
SCOPE
1.1 This specification covers round, square, rectangular, and special shape, electric-resistance-welded mechanical tubing, either zinc-coated (galvanized) after welding or produced from aluminum-coated, zinc-coated (galvanized), zinc-iron alloy-coated (galvannealed), or 55 % aluminum-zinc alloy-coated steel sheet. Tubing for use as electrical conduit (EMT) or intermediate metallic conduit (IMC) is not covered by this specification.
1.2 This specification covers mechanical tubing with outside diameters or maximum outside dimensions ranging from 1/2 to 8 in. (12.7 to 203.2 mm) and wall thickness from 0.028 to 0.134 in. (0.71 to 3.40 mm).
1.3 Sizes outside the ranges listed above may be ordered provided all other requirements of the specification are met.
1.4 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: A 787 – 00 An American National Standard
Standard Specification for
Electric-Resistance-Welded Metallic-Coated Carbon Steel
Mechanical Tubing
This standard is issued under the fixed designation A 787; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope B 6 Specification for Zinc
1.1 This specification covers round, square, rectangular, and
3. Classification
special shape, electric-resistance-welded mechanical tubing,
3.1 The types of tubing covered by this specification are:
either zinc-coated (galvanized) after welding or produced from
Type Code Description
aluminum-coated, zinc-coated (galvanized), zinc-iron alloy-
Number Letters
coated (galvannealed), or 55 % aluminum-zinc alloy-coated
steel sheet. Tubing for use as electrical conduit (EMT) or 1 AWAC electric-resistance-welded aluminum-
coated carbon steel mechanical tubing
intermediate metallic conduit (IMC) is not covered by this
2 AWG electric-resistance-welded galvanized car-
specification.
bon steel mechanical tubing
1.2 This specification covers mechanical tubing with out- 3 AWPG electric-resistance-welded carbon steel
mechanical tubing, post-hot dipped gal-
side diameters or maximum outside dimensions ranging from
vanized
⁄2 to 8 in. (12.7 to 203.2 mm) and wall thickness from 0.028
4 AWGA electric-resistance-welded carbon steel
mechanical tubing, zinc-iron alloy-
to 0.134 in. (0.71 to 3.40 mm).
coated (galvannealed)
1.3 Sizes outside the ranges listed above may be ordered
5 AWGZ electric-resistance-welded carbon steel
provided all other requirements of the specification are met.
mechanical tubing, 55 % aluminum-zinc
alloy-coated
1.4 The values stated in inch-pound units are to be regarded
as the standard. The values given in parentheses are for
4. Ordering Information
information only.
4.1 The ordered wall thickness of the tubing shall be the
2. Referenced Documents total of the base metal and the metallic coating.
4.2 Orders for material under this specification shall in-
2.1 ASTM Standards:
clude the following:
A 90/A 90M Test Method for Weight [Mass] of Coating on
4.2.1 Quantity (feet, metres, or number of lengths),
Iron and Steel Articles with Zinc or Zinc-Alloy Coatings
4.2.2 Type, code letters, and description (Sections 1 and 3),
A 370 Test Methods and Definitions for Mechanical Testing
4.2.3 Applicable ASTM designation number(s),
of Steel Products
4.2.4 Coating designation and type of coating,
A 428/A 428M Test Method for Weight of Coating on
4.2.5 Chemically treated or not chemically treated raw
Aluminum-Coated Iron or Steel Articles
material,
A 463/A 463M Specification for Steel Sheet, Aluminum-
4.2.6 Oiled or dry (Section 16),
Coated by the Hot-Dip Process
4.2.7 Extra smooth coating (if required),
A 653/A 653M Specification for Steel Sheet, Zinc-Coated
4.2.8 Customer application, including fabrication,
(Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed)
4.2.9 Flash condition (7.1),
by the Hot-Dip Process
4.2.10 Steel grade designation (Sections 5 and 9),
A 792/A 792M Specification for Steel Sheet, 55 Aluminum-
4.2.11 Report of chemical analysis if required (Sections 10
Zinc Alloy-Coated by the Hot-Dip Process
and 11),
A 924/A 924M Specification for General Requirements for
4.2.12 Shape (round, square, rectangular, or special),
Steel Sheet, Metallic-Coated by the Hot-Dip Process
4.2.12.1 Dimensions: round—any two of the following:
inside diameter, outside diameter, or wall thickness; square or
rectangular—outside dimension, wall thickness, and corner
This specification is under the jurisdiction of ASTM Committee A01 on Steel,
radii, if required. (See 12.1 and 13.1 and 13.2.)
Stainless Steel, and Related Alloys and is the direct responsibility of Subcommittee
4.2.13 Length: round tubing—mill lengths or definite cut
A01.09 on Carbon Steel Tubular Products.
lengths (see 12.2); square and rectangular tubing—mill cut
Current edition approved Sept. 10, 2000. Published November 2000. Originally
published as A 787 – 81. Last previous edition A 787 – 96.
Annual Book of ASTM Standards, Vol 01.06.
3 4
Annual Book of ASTM Standards, Vol 01.03. Annual Book of ASTM Standards, Vol 02.04.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
A 787
A
TABLE 2 Chemical Requirements for Other Carbon Steels
lengths and specified length (see 13.4).
4.2.14 Squareness of cut: round tubing, if required (see Composition, %
Grade
12.3); square and rectangular tubing, if required (see 13.7),
Phos-
Designa-
Sulfur,
Carbon Manganese phorus,
4.2.15 Burrs removed, if required (see 15.2), tion
max
max
4.2.16 Special packaging (Section 19),
1008 0.10 max 0.50 0.035 0.035
4.2.17 Customer specification number, if applicable,
1010 0.08 to 0.13 0.30 to 0.60 0.035 0.035
4.2.18 Special requirements,
1015 0.12 to 0.18 0.30 to 0.60 0.035 0.035
1016 0.12 to 0.19 0.60 to 0.90 0.035 0.035
4.2.19 Special marking (Section 18), and
1017 0.14 to 0.21 0.30 to 0.60 0.035 0.035
4.2.20 Recoating of outside diameter weld and heat-
1018 0.14 to 0.21 0.60 to 0.90 0.035 0.035
affected area, on precoated steel, if required.
1019 0.14 to 0.21 0.70 to 1.00 0.035 0.035
1021 0.17 to 0.24 0.60 to 0.90 0.035 0.035
5. Process
A
Chemistry represents heat analysis. Product analysis, except for rimmed or
5.1 The steel shall be made from any process.
capped steel, is to be in accordance with usual practice as shown in Table 5.
5.1.1 If a specific type of melting is required by the
purchaser, it shall be stated on the purchase order.
6.2 Special manufacturing practices allow for post-hot
5.1.2 The primary melting may incorporate separate degas-
dipped galvanizing of welded tubing. If this product is desired
sing or refining and may be followed by secondary melting,
all sections of this specification will apply except Table 3. Wall
using electroslag remelting or vacuum remelting. If secondary
thickness tolerances shall be determined by agreement between
melting is employed, the heat shall be defined as all of the
the producer and purchaser.
ingots remelted from a single primary heat.
5.1.3 Steel may be cast in ingots or may be strand cast. 7. Flash Conditions
When steel of different grades is sequentially strand cast,
7.1 The flash conditions under which tubing may be
identification of the resultant transition material is required.
furnished are as follows: The flash shall be removed from the
The producer shall remove the transition material by an
outside diameter of tubing covered by this specification.
established procedure that positively separates the grades.
Tubing furnished to this specification may have the following
5.2 For tubing produced from precoated steel sheet, the
conditions of welding flash on the inside diameter.
composition of the coating shall comply with the applicable
7.1.1 Flash-In— All tubing in which the inside diameter
specification.
welding flash does not exceed the wall thickness or ⁄32 in. (2.4
5.2.1 Specification A 463/A 463M—Coating designation for
mm), whichever is less.
aluminum coated-sheet.
7.1.2 Flash Controlled to 0.010 in. (0.254 mm),
5.2.2 Specification A 653/A 653M—Coating designation for
Maximum— Tubing in which the height of the remaining
galvanized and galvannealed steel sheet.
welding flash is controlled so as not to exceed 0.010 in. This
5.2.3 Specification A 792/A 792M—Coating designation for
condition is available in over 0.750 in. (19.05 mm) outside
55 % aluminum-zinc alloy-coated steel sheet.
diameter and gages consistent with Table 4.
5.2.4 Other grades of coated steel sheet, as listed in Table 1
7.1.3 Flash Controlled to 0.005 in. (0.127 mm),
and Table 2, may be used as the precoated material for the steel
Maximum—When the inside diameter flash is controlled to
tubing upon agreement between the manufacturer and the
0.005 in. (0.127 mm) maximum in tubing produced to outside
purchaser. Such steel sheet shall meet the requirements of
diameter and wall thickness, inside diameter and wall thick-
Specification A 463/A 463M, A 653/A 653M, A 792/A 792M,
ness, or outside diameter and inside diameter tolerances, the
and A 924/A 924M, except for the chemical requirements.
remaining inside diameter flash, if any, is part of the applicable
6. Manufacture inside diameter tolerance. This controlled flash is available in
0.750 in. (19.05 mm) outside diameter or greater.
6.1 Tubes shall be made by the electric-resistance welding
7.2 Tubes shall be furnished in the following shapes, as
process and shall be made from hot or cold-rolled precoated
specified by the purchaser: round, square, rectangular, or
steel.
special shapes (as negotiated).
A,B
TABLE 1 Chemical Requirements for Low-Carbon Steels
7.3 Recoating of the outside diameter weld-heat-affected
Composition, %
area on precoated steel tubing may be performed at the
Grade
Phos-
manufacture’s option, if not specifically requested by the
C Sulfur,
Designation
Carbon Manganese phorus,
max purchaser.
max
MT1010 0.05 to 0.15 0.30 to 0.60 0.035 0.035
8. Surface Finish
MT1015 0.10 to 0.20 0.30 to 0.60 0.035 0.035
MTX1015 0.10 to 0.20 0.60 to 0.90 0.035 0.035 8.1 Special surface finishes as may be required for specific
MT1020 0.15 to 0.25 0.30 to 0.60 0.035 0.035
applications shall be provided in the purchase order by
MTX1020 0.15 to 0.25 0.70 to 1.00 0.035 0.035
agreement between the producer and purchaser.
A
Rimmed or capped steels that may be used for the above grades are
characterized by a lack of uniformity in their chemical composition, and for this
9. Base Metal Chemical Composition
reason product analysis is not technologically appropriate unless misapplication is
clearly indicated.
9.1 The chemical composition of the sheet steel base metal
B
Chemistry represents heat analysis. Product analysis, except for rimmed or
shall conform to the requirements of Table 1.
capped steel, is to be in accordance with usual practice as shown in Table 5.
C
The letters MT indicate mechanical tubing. 9.2 Copper-bearing steel, with 0.20 % minimum copper,
A 787
A
TABLE 3 Wall Thickness Tolerance for Premetallic Coated As-Welded Tubing
Outside Diameter, in.
15 3 1
Over 1 to Over 1 ⁄16 to Over 3 ⁄4 to Over 4 ⁄2 to Over 6 to
Wall Thickness ⁄2 to 1, incl
15 3 1
1 ⁄16, incl 3 ⁄4, incl 4 ⁄2, incl 6, incl 8, incl
Wall Thickness Tolerance, in., Plus and Minus
B C
BWG in. Plus Minus Plus Minus Plus Minus Plus Minus Plus Minus Plus Minus
22 0.028 0.002 0.006 0.002 0.006
20 0.035 0.003 0.006 0.002 0.006 0.002 0.006
18 0.049 0.004 0.007 0.003 0.008 0.003 0.008
16 0.065 0.005 0.007 0.004 0.008 0.003 0.009 0.003 0.009 0.002 0.010
14 0.083 0.006 0.008 0.006 0.008 0.005 0.009 0.005 0.009 0.004 0.010 0.004 0.010
13 0.095 0.008 0.010 0.008 0.010 0.007 0.011 0.007 0.011 0.006 0.012 0.006 0.012
12 0.109 0.008 0.010 0.008 0.010 0.007 0.011 0.007 0.011 0.006 0.012 0.006 0.012
11 0.120 0.009 0.011 0.009 0.011 0.008 0.012 0.008 0.012 0.007 0.013 0.007 0.013
10 0.134 0.009 0.011 0.009 0.011 0.008 0.012 0.008 0.012 0.007 0.013 0.007 0.013
A
Post-hot dipped galvanized welded tubing wall thickness tolerances shall be determined by agreement between the producer and purchaser (6.2).
B
Birmingham Wire Gage.
C
1 in. = 25.4 mm.
may be ordered in any of the grades shown in Table 1 or Table specification; otherwise, all remaining material in the heat or
2. lot shall be rejected or, at the option of the producer, each
9.3 An analysis of each heat of steel shall be made by the length of flat-rolled stock or tube may be individually tested for
basic steel producer to determine the percentage of the ele- acceptance. Any retested material not meeting the requirements
ments specified. The heat analysis, as supplied by the steel of this specification shall be rejected.
melter, shall conform to the requirements of Table 1 or Table 2.
12. Permissible Variations in Dimensions for Round
9.4 When a grade is ordered under this specification,
Tubing
supplying an alloy grade that specifically requires the addition
of any element other than those listed for the ordered grade in
12.1 Wall Thickness and Diameter— Wall thickness toler-
Table 1 and Table 2 is not permitted. ances for tubing made from precoated steel are shown in Table
3. All wall thickness tolerances include both the base steel and
10. Coating Bath Chemical Composition
the coating (inside and outside surfaces). Variations in outside
10.1 When tubing is produced from precoated sheet steel, diameter and inside diameter of as-welded tubing made from
the tubing manufacturer shall furnish, upon request, a report precoated steel are shown in Table 4.
stating that the tubing has been manufactured from precoated 12.2 Length— Mechanical tubing is commonly furnished in
sheet steel meeting one of the following specifications: A 463/ mill lengths 5 ft (1.5 m) and over. Mill length tolerances are
A 463M, A 653/A 653M, A 792/A 792M, and A 924/A 924M. given in Table 6. Definite cut lengths are furnished when
10.2 For post-coated tubing the zinc used for coating shall specified by the purchaser. Tolerances for definite length round
be any grade of zinc conforming to Specification B 6. tubing are given in Table 7.
12.3 Squareness of Cut— When specified, the tolerance for
11. Product Analysis
squareness of cut of round mechanical tubing is shown in Table
11.1 When requested on the purchase order, a product 8. Measurements are made with the use of an “L” square and
analysis shall be made by the supplier. The number and source feeler gage. The contact length of the side leg of the square
of samples for a product analysis shall be based on the along the tube will be equal to or greater than the tube outside
individual heat or lot identity of one of the following forms: diameter, but not less than 1 in. (25.4 mm) nor greater than 4
11.1.1 Heat Identity Maintained— One product analysis per in. (101.6 mm). The other leg shall always be equal to or
heat shall be made on either the flat-rolled stock or tube. greater than the tube outside diameter.
11.1.2 Heat Identity Not Maintained— One product analy- 12.4 Straightness:
sis shall be made from each 2000 ft (610 m) or fraction thereof 12.4.1 Post-Coated Tubing— The straightness tolerance for
for sizes over 3 in. (76.2 mm) outside diameter, and from each round mechanical tubing shall be 0.030 in. (0.762 mm)
5000 ft (1524 m) or fraction thereof for sizes 3 in. (76.2 mm) maximum in any 3-ft (0.914-m) length of tubing. The straight-
outside diameter and under. ness tolerance on shorter lengths and on special requirements
11.2 Samples for product spectroch
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