Designation: A 789/A 789M – 00a An American National Standard

Standard Specification for

Seamless and Welded Ferritic/Austenitic Stainless Steel
Tubing for General Service1
This standard is issued under the fixed designation A 789/A 789M; 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 TABLE 1 Tensile and Hardness Requirements

1.1 This specification2 covers grades of nominal wall thick- Tensile Yield Elongation Hardness, max
Strength, Strength, in 2 in. or
ness, stainless steel tubing for services requiring general UNS Designation
min, ksi min, ksi 50 mm, Brinell Rock-
corrosion resistance, with particular emphasis on resistance to [MPa] [MPa] min, % well C
stress corrosion cracking. These steels are susceptible to S31803 90 [620] 65 [450] 25 290 30.5
embrittlement if used for prolonged periods at elevated tem- S32205 90 [620] 65 [450] 25 290 30.5
S32205 95 [655] 70 [485] 25 290 30.5
peratures. S31500 92 [630] 64 [440] 30 290 30.5
S32550 110 [760] 80 [550] 15 297 31.5
NOTE 1—For tubing smaller than 1⁄2in. [12.7 mm] in outside diameter,
S31200 100 [690] 65 [450] 25 280 ...
the elongation values given for strip specimens in Table 1 shall apply. S31260A 100 [690] 65 [450] 25 290 30.5
Mechanical property requirements do not apply to tubing smaller than S32304
1⁄8in. [3.2 mm] in outside diameter or with walls thinner than 0.015 in. [0.4 OD 1 in. [25 mm] and
mm]. Under 100 [690] 65 [450] 25 ... ...
OD over 1 in. [25 mm] 87 [600] 58 [400] 25 290 30.5
1.2 The values stated in either inch-pound units or SI units S39274 116 [800] 80 [550] 15 310 ...
are to be regarded separately as standard. Within the text, the S32750 116 [800] 80 [550] 15 310 32
S32760 109 [750] 80 [550] 25 300 ...
SI units are shown in brackets. The values stated in each
system are not exact equivalents; therefore, each system must S32900 90 [620] 70 [485] 20 271 28
be used independently of the other. Combining values from the S32950B 100 [690] 70 [480] 20 290 30.5
S39277 120 [825] 90 [620] 25 290 30
two systems may result in nonconformance with the specifi- S32520 112 [770] 80 [550] 25 310 ...
cation. The inch-pound units shall apply unless the M desig- A
Prior to A 789/A 789M – 87, the values for S31260 were: 92 ksi tensile
nation of this specification is specified in the order. strength, 54 ksi yield strength, and 30 % elongation.
B
Prior to A 789/A 789M – 89, the tensile strength value was 90 ksi for UNS
2. Referenced Documents S32950.

2.1 ASTM Standards: include the following, as required, to describe the desired
A 450/A 450M Specification for General Requirements for material adequately:
Carbon, Ferritic Alloy, and Austenitic Alloy Steel Tubes3 3.1.1 Quantity (feet, metres, or number of lengths),
A 480/A 480M Specification for General Requirements for 3.1.2 Name of material (seamless or welded tubes),
Flat-Rolled Stainless and Heat-Resisting Steel Plate, 3.1.3 Grade (see Table 2),
Sheet, and Strip4 3.1.4 Size (outside diameter and nominal wall thickness),
E 527 Practice for Numbering Metals and Alloys (UNS)3 3.1.5 Length (specific or random),
2.2 SAE Standard:5 3.1.6 Optional requirements (product analysis for welded
SAE J 1086 tubes, Section 8; hydrostatic test or nondestructive electric test,
Section 10),
3. Ordering Information
3.1.7 Test report required (section on inspection of Specifi-
3.1 Orders for material under this specification should cation A 450/A 450M),
3.1.8 Specification designation, and
1
This specification is under the jurisdiction of ASTM Committee A01 on Steel, 3.1.9 Special requirements.
Stainless Steel, and Related Alloys and is the direct responsibility of Subcommittee
A01.10 on Stainless and Alloy Steel Tubular Products. 4. General Requirements
Current edition approved July 10, 2000. Published September 2000. Originally
published as A 789 – 81. Last previous edition A 789/A 789M – 00. 4.1 Material furnished under this specification shall con-
2
For ASME Boiler and Pressure Vessel Code applications see related Specifi- form to the applicable requirements of Specification A 450/
cation SA–789 in Section II of that Code. A 450M, unless otherwise provided herein.
3
Annual Book of ASTM Standards, Vol 01.01.
4
Annual Book of ASTM Standards, Vol 01.03. 5. Manufacture
5
Available from Society of Automotive Engineers, 400 Commonwealth Drive,
Warrendale, PA 15096. 5.1 The tubes shall be made by the seamless or welded

Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.

1
 A 789/A 789M
TABLE 2 Chemical Requirements
UNS
C Mn P S Si Ni Cr Mo N Cu Others
DesignationA
S31803 0.030 max 2.0 max 0.030 max 0.020 max 1.0 max 4.50–6.50 21.0–23.0 2.50–3.50 0.08–0.20 ... ...
S31500 0.030 max 1.20–2.00 0.030 max 0.030 max 1.40–2.00 4.25–5.25 18.0–19.0 2.50–3.00 0.05–0.1 ... ...
S32550 0.040 1.5 max 0.040 max 0.030 max 1.0 max 4.50–6.50 24.0–27.0 2.90–3.90 0.10–0.25 1.5–2.5 ...
S31200 0.030 max 2.0 max 0.045 max 0.030 max 1.0 max 5.50–6.50 24.0–26.0 1.20–2.00 0.14–0.20 ... ...
S31260 0.030 max 1.00 max 0.030 max 0.030 max 0.75 max 5.50–7.50 24.0–26.0 2.50–3.50 0.10–0.30 0.20–0.80 W 0.10–0.50
S32304 0.030 max 2.50 max 0.040 max 0.040 max 1.0 max 3.0–5.5 21.5–24.5 0.05–0.60 0.05–0.20 0.05–0.60 ...
S39274 0.030 max 1.0 max 0.030 max 0.020 max 0.80 max 6.0–8.0 24.0–26.0 2.50–3.50 0.24–0.32 0.20–0.80 W 1.50–2.50
S32750 0.030 max 1.2 max 0.035 max 0.020 max 0.8 max 6.0–8.0 24.0–26.0 3.0–5.0 0.24–0.32 0.5 max ...
S32760 0.05 max 1.00 max 0.030 max 0.010 max 1.00 max 6.00–8.00 24.00–26.00 3.00–4.00 0.20–0.30 0.50–1.00 W 0.50–1.00
40 minB
S32900 0.08 max 1.00 max 0.040 max 0.030 max 0.75 max 2.50–5.00 23.00–28.00 1.00–2.00 ... ... ...
S32950 0.03 max 2.00 max 0.035 max 0.010 max 0.60 max 3.50–5.20 26.00–29.00 1.00–2.50 0.15–0.35 ... ...
S39277 0.025 max 0.80 max 0.025 max 0.002 max 0.80 max 6.50–8.00 24.00–26.00 3.00–4.00 0.23–0.33 1.2–2.0 W 0.8–1.2
S32520 0.030 max 1.50 max 0.035 max 0.020 max 0.80 max 5.5–8.0 23.0–25.0 3.0–5.0 0.20–0.35 0.50–3.00 ...
A
New designation established in accordance with Practice E 527 and SAE J1086.
B
% Cr + 3.3 3 % Mo + 163 % N.

process with no filler metal added. chemical composition thus determined shall conform to the
requirements specified.
6. Heat Treatment 8.2 A product analysis tolerance of Table labeled A1.1 in
6.1 All tubes shall be furnished in the heat-treated condition Specification A 480/A 480M shall apply. The product analysis
in accordance with the procedures shown in Table 3. For tolerance is not applicable to the carbon content for material
seamless tubes, as an alternate to final heat treatment in a with a specified maximum carbon of 0.04 % or less.
continuous furnace or batch-type furnace, immediately follow- 8.3 If the original test for product analysis fails, retests of
ing hot forming while the temperature of the tubes is not less two additional billets, lengths of flat-rolled stock, or tubes shall
than the specified minimum solution treatment temperature, be made. Both retests for the elements in question shall meet
tubes may be individually quenched in water or rapidly cooled the requirements of this specification; otherwise, all remaining
by other means. material in the heat or lot (see Note 2) shall be rejected or, at
7. Chemical Composition the option of the producer, each billet or tube may be
individually tested for acceptance. Billets, lengths of flat-rolled
7.1 The steel shall conform to the chemical requirements stock, or tubes that do not meet the requirements of this
prescribed in Table 2. specification shall be rejected.
8. Product Analysis NOTE 2—For flange and flaring requirements, the term lot applies to all
8.1 An analysis of either one billet or one length of tubes prior to cutting of the same nominal size and wall thickness that are
flat-rolled stock or one tube shall be made from each heat. The produced from the same heat of steel. When final heat treatment is in a
batch-type furnace, a lot shall include only those tubes of the same size
TABLE 3 Heat Treatment and from the same heat that are heat treated in the same furnace charge.
When the final heat treatment is in a continuous furnace, or when heat
UNS treated condition is obtained directly by quenching after hot forming, the
Temperature Quench
Designation
number of tubes of the same size and from the same heat in a lot shall be
S31803 1870–2010°F rapid cooling in air or water determined from the size of the tubes as prescribed in Table 4.
[1020–1100°C] NOTE 3—For tension and hardness test requirements, the term lot
S31500 1800–1900°F rapid cooling in air or water
[980–1040°C]
applies to all tubes prior to cutting, of the same nominal diameter and wall
S32550 1900°F rapid cooling in air or water thickness that are produced from the same heat of steel. When final heat
[1040°C] min treatment is in a batch-type furnace, a lot shall include only those tubes of
S31200 1920–2010°F rapid cooling in water the same size and the same heat that are heat treated in the same furnace
[1050–1100°C] charge. When the final heat treatment is in a continuous furnace, or when
S31260 1870–2010°F rapid cooling in water heat treated condition is obtained directly by quenching after hot forming,
[1020–1100°C]
S32304 1700–1920°F rapid cooling in air or water
a lot shall include all tubes of the same size and heat, heat treated in the
[925–1050°C]
S39274 1920–2060°F rapid cooling in air or water
[1025–1125°C] TABLE 4 Number of Tubes in a Lot Heat Treated by the
S32750 1880–2060°F rapid cooling in air or water Continuous Process or by Direct Quench after Hot Forming
[1025–1125°C]
S32760 2010–2085°F rapid cooling in air or water
Size of Tube Size of Lot
[1100–1140°C]
S32900 1700–1750°F rapid cooling in air or water 2 in. [50.8 mm] and over in outside diameter not more than 50 tubes
[925–955°C] and 0.200 in. [5.1 mm] and over
S32950 1820–1880°F air cool in wall thickness
[990–1025°C] Less than 2 in. [50.8 mm] but over 1 in. [25.4 not more than 75 tubes
S39277 1975–2155°F rapid cooling in air or water mm] in outside diameter or over 1 in.
[1080–1180°C] [25.4 mm] in outside diameter and under
S32520 1975–2050°F rapid cooling in air or water 0.200 in. [5.1 mm] in wall thickness
[1080–1120°C] 1 in. [25.4 mm] or less in outside diameter not more than 125 tubes

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 A 789/A 789M
same furnace at the same temperature, time at heat, and furnace speed, or specified in the purchase order.
all tubes of the same size and heat, hot formed and quenched in the same 10.2 The hydrostatic test shall be in accordance with Speci-
production run. fication A 450/A 450M, except that in the calculation of the
hydrostatic test pressure 64000(441.2) shall be substituted for
9. Mechanical Tests Required 32000(220.6).
9.1 Tension Tests—One tension test shall be made on a 11. Tensile and Hardness Properties
specimen for lots of not more than 50 tubes. Tension tests shall
11.1 The material shall conform to the tensile and hardness
be made on specimens from two tubes for lots of more than 50
properties prescribed in Table 1.
tubes (see Note 3).
12. Permissible Variations in Dimensions
9.2 Flaring Test (for Seamless Tubes)—One test shall be
made on specimens from one end of one tube from each lot 12.1 Variations in outside diameter, wall thickness, and
(see Note 2) of finished tubes. The minimum expansion of the length from those specified shall not exceed the amounts
inside diameter shall be 10 %. prescribed in Table 5.
12.2 The permissible variations in outside diameter given in
9.3 Flange Test (for Welded Tubes)—One test shall be made
Table 5 are not sufficient to provide for ovality in thin-walled
on specimens from one end of one tube from each lot (see Note tubes, as defined in the table. In such tubes, the maximum and
2) of finished tubes. minimum diameters at any cross section shall deviate from the
9.4 Hardness Test—Brinell or Rockwell hardness tests shall nominal diameter by no more than twice the permissible
be made on specimens from two tubes from each lot (see Note variation in outside diameter given in Table 5; however, the
3). mean diameter at that cross section must still be within the
9.5 When more than one heat is involved, the tension, given permissible variation.
flaring, flanging, and hardness test requirements shall apply to 13. Surface Condition
each heat. 13.1 All tubes shall be free of excessive mill scale, suitable
9.6 Reverse Flattening Test—For welded tubes, one reverse for inspection. A slight amount of oxidation will not be
flattening test shall be made on a specimen from each 1500 ft considered as scale. Any special finish requirements shall be
[450 m] of finished tubing. subject to agreement between the manufacturer and the pur-
chaser.
10. Hydrostatic or Nondestructive Electric Test 14. Product Marking
10.1 Each tube shall be subjected to the nondestructive 14.1 In addition to the marking prescribed in Specification
electric test or the hydrostatic test. The type of test to be used A 450/A 450M, the marking shall indicate whether the tubing
shall be at the option of the manufacturer, unless otherwise is seamless or welded.
15. Keywords
15.1 duplex stainless steel; ferritic/austenitic stainless steel;
seamless steel tube; stainless steel tube; steel tube; welded steel
tube

TABLE 5 Permissible Variations in Dimensions

Size, Outside Permissible Variations in Permissible Permissible Variations in Cut
Group Diameter, in. Outside Diameter, in. Variations in Wall Length, in.B [mm] Thin Walled TubesC
[mm] [mm] Thickness,A % Over Under
1 Up to 1⁄2 [12.7], excl 60.005 [0.13] 615 ⁄ [3]
18 0 ...
2 ⁄ to 11⁄2 [12.7 to 38.1], excl
12 60.005 [0.13] 610 ⁄ [3]
18 0 less than 0.065 in. [1.6 mm] nominal
3 11⁄2 to 31⁄2 [38.1 to 88.9], excl 60.010 [0.25] 610 ⁄ [5]
3 16 0 less than 0.095 in. [2.4 mm] nominal
4 31⁄2 to 51⁄2 [88.9 to 139.7], excl 60.015 [0.38] 610 3⁄16 [5] 0 less than 0.150 in. [3.8 mm] nominal
5 51⁄2 to 8 [139.7 to 203.2], incl 60.030 [0.76] 610 3⁄16 [5] 0 less than 0.150 in. [3.8 mm] nominal
A
When tubes as ordered require wall thicknesses 3⁄4 in. [19 mm] or over, or an inside diameter 60 % or less of the outside diameter, a wider variation in wall thickness
is required. On such sizes a variation in wall thickness of 12.5 % over or under will be permitted.
For tubes less than 1⁄2 in. [12.7 mm] in inside diameter that cannot be successfully drawn over a mandrel, the wall thickness may vary 615 % from that specified.
B
These tolerances apply to cut lengths up to and including 24 ft [7.3 m]. For lengths greater than 24 ft [7.3 m], the above over-tolerances shall be increased by 1⁄8 in.
[3 mm] for each 10 ft [3 m] or fraction thereof over 24 ft or 1⁄2 in. [13 mm], whichever is the lesser.
C
Ovality provisions of 12.2 apply.

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 A 789/A 789M
SUPPLEMENTARY REQUIREMENTS

The following supplementary requirement shall apply only when specified by the purchaser in the
inquiry, contract, or order.

S1. Air-Underwater Pressure Test plings shall be corrected prior to testing.

S1.1 Each tube, with internal surface clean and dry, shall be S1.4 After holding the pressure for not less than 5 s after the
internally pressurized to 150 psi [1000 kPa] minimum with surface of the water has become calm, an inspection shall be
clean and dry compressed air while being submerged in clear made of the entire external surface of the tube.
water. S1.5 If any tube leaks during the air-underwater test, it shall
S1.2 The tube shall be well-lighted, preferably by underwa- be rejected. Any leaking areas may be cut out and the tube
ter illumination. retested as in S1.1 through S1.4.
S1.3 Any evidence of air leakage of the pneumatic cou-

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