|A249/ A249M||A269||A270||A778||A335/ A335M||A691|
|A790||A312||A409||A554||A358/ A358M||A928/ A928M|
CS pipe Grades
Standard Specification for
Welded Austenitic Steel Boiler, Superheater, Heat-
Exchanger, and Condenser Tubes
This standard is issued under the fixed designation A 249/A 249M; 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.
This standard has been approved for use by agencies of the Department of Defense.
1.1 This specification2 covers nominal-wall-thickness
welded tubes and heavily cold worked welded tubes made from
the austenitic steels listed in Table 1, with various grades
intended for such use as boiler, superheater, heat exchanger, or
1.2 Grades TP304H, TP309H, TP309HCb, TP310H,
TP310HCb, TP316H, TP321H, TP347H, and TP348H are
modifications of Grades TP304, TP309S, TP309Cb, TP310S,
TP310Cb, TP316, TP321, TP347, and TP348, and are intended
for high-temperature service such as for superheaters and
1.3 The tubing sizes and thicknesses usually furnished to
this specification are 1⁄8 in. [3.2 mm] in inside diameter to 12 in.
[304.8 mm] in outside diameter and 0.015 to 0.320 in. [0.4 to
8.1 mm], inclusive, in wall thickness. Tubing having other
dimensions may be furnished, provided such tubes comply
with all other requirements of this specification.
1.4 Mechanical property requirements do not apply to
tubing smaller than 1⁄8 in. [3.2 mm] in inside diameter or 0.015
in. [0.4 mm] in thickness.
1.5 Optional supplementary requirements are provided and,
when one or more of these are desired, each shall be so stated
in the order.
1.6 The values stated in either inch-pound units or SI units
are to be regarded separately as standard. Within the text, the
SI units are shown in brackets. The values stated in each
system are not exact equivalents; therefore, each system must
be used independently of the other. Combining values from the
two systems may result in nonconformance with the specification.
The inch-pound units shall apply unless the “M”
designation of this specification is specified in the order.
1.7 The following safety hazards caveat pertains only to the
test method described in the Supplementary Requirements of
this specification. This standard does not purport to address all
of the safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appropriate
safety and health practices and determine the applicability
of regulatory limitations prior to use. A specific warning
statement is given in Supplementary Requirement S7, Note
2. Referenced Documents
2.1 ASTM Standards: 3
A 262 Practices for Detecting Susceptibility to Intergranular
Attack in Austenitic Stainless Steels
A 480/A 480M Specification for General Requirements for
Flat-Rolled Stainless and Heat-Resisting Steel Plate,
Sheet, and Strip
A 1016/A 1016M Specification for General Requirements
for Ferritic Alloy Steel, Austenitic Alloy Steel, and Stainless
E 112 Test Methods for Determining Average Grain Size
E 213 Practice for Ultrasonic Examination of Metal Pipe
E 273 Practice for Ultrasonic Examination of the Weld
Zone of Welded Pipe and Tubing
E 527 Practice for Numbering Metals and Alloys (UNS)
2.2 ASME Boiler and Pressure Vessel Code:
Section VIII 4
2.3 Other Standard:
SAE J1086 Practice for Numbering Metals and Alloys
3. Ordering Information
3.1 It is the responsibility of the purchaser to specify all
requirements that are necessary for material ordered
under this specification. Such requirements may include,
but are not limited to, the following:
3.1.1 Quantity (feet, metres, or number of lengths),
3.1.2 Name of material welded tubes (WLD) or heavily cold
worked tubes (HCW),
3.1.3 Grade (Table 1),
3.1.4 Size (outside diameter and nominal wall thickness),
3.1.5 Length (specific or random),
3.1.6 Optional requirements (13.6),
3.1.7 Test report required (see Certification Section of
Specification A 1016/A 1016M),
3.1.8 Specification designation, and
3.1.9 Special requirements and any supplementary requirements
4. General Requirements
4.1 Material furnished under this specification shall conform
to the applicable requirements of the current edition of
Specification A 1016/A 1016M, unless otherwise provided
5.1 The welded (WLD) tubes shall be made from flat-rolled
steel by an automatic welding process with no addition of filler
5.1.1 Subsequent to welding and prior to final heat treatment,
the tubes shall be cold worked either in both weld and
base metal or in weld metal only. The method of cold working
may be specified by the purchaser. When cold drawn, the
purchaser may specify the minimum amount of reduction in
cross-sectional area or wall thickness, or both.
5.1.2 Heavily cold worked (HCW) tubes shall be made by
applying cold working of not less than 35 % reduction in both
wall and weld to a welded tube prior to the final anneal. No
filler metal shall be used in the making of the weld. Prior to
cold working, the weld shall be 100 % radiographically inspected
in accordance with the requirements of ASME Boiler
and Pressure Vessel Code, Section VIII, Division 1, latest
revision, Paragraph UW 51.
|TABLE 1 Chemical Requirements, %|
6. Heat Treatment
6.1 All material shall be furnished in the heat-treated
condition in accordance with the requirements of Table 2.
6.2 A solution annealing temperature above 1950 °F [1065
°C] may impair the resistance to intergranular corrosion after
subsequent exposure to sensitizing conditions in TP309HCb,
TP310HCb, TP321, TP321H, TP347, TP347H, TP348, and
TP348H. When specified by the purchaser, a lower temperature
stabilization or re-solution anneal shall be used subsequent to
the initial high temperature solution anneal (see Supplementary
7. Chemical Composition
7.1 The heat analysis shall conform to the requirements as
to chemical composition given in Table 1.
8. Product Analysis
8.1 An analysis of either one length of flat-rolled stock or
one tube shall be made for each heat. The chemical composition
thus determined shall conform to the requirements given in
8.2 A product analysis tolerance of Table A1.1 in Specification
A 480/A 480M shall apply. The product analysis tolerance
is not applicable to the carbon content for material with a
specified maximum carbon of 0.04 % or less.
8.3 If the original test for product analysis fails, retests of
two additional lengths of flat-rolled stock or tubes shall be
made. Both retests for the elements in question shall meet the
requirements of the specification; otherwise all remaining
material in the heat or lot (See Note 1) shall be rejected or, at
the option of the producer, each length of flat-rolled stock or
tube may be individually tested for acceptance. Lengths of
flat-rolled stock or tubes that do not meet the requirements of
the specification shall be rejected.
NOTE 1—For flattening and flange requirements, the term lot applies to
all tubes prior to cutting of the same nominal size and wall thickness
which are 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 and from the same heat which are heat treated in the same furnace
charge. When the final heat treatment is in a continuous furnace, the
number of tubes of the same size and from the same heat in a lot shall be
determined from the size of the tubes as prescribed in Table 3.
NOTE 2—For tension and hardness test requirements, the term lot
applies to all tubes prior to cutting, of the same nominal diameter and wall
thickness which are 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 and the same heat which are heat treated in the same furnace
charge. When the final heat treatment is in a continuous furnace, a lot shall
include all tubes of the same size and heat, annealed in the same furnace
at the same temperature, time at heat, and furnace speed.
9. Tensile Requirements
9.1 The material shall conform to the tensile properties
prescribed in Table 4.
10. Hardness Requirements
10.1 The tubes shall have a Rockwell hardness number not
exceeding the values specified in Table 4.
11. Reverse-Bend Test Requirement
11.1 A section 4 in. [100 mm] minimum in length shall be
split longitudinally 90° on each side of the weld. The sample
shall then be opened and bent around a mandrel with a
maximum thickness of four times the wall thickness, with the
mandrel parallel to the weld and against the original outside
surface of the tube. The weld shall be at the point of maximum
bend. There shall be no evidence of cracks, or of overlaps
resulting from the reduction in thickness of the weld areas by
cold working. When the geometry or size of the tubing make it
difficult to test the sample as a single piece, the sample may be
sectioned into smaller pieces provided a minimum of 4 in. of
weld is subjected to reverse bending.
NOTE 3—The reverse bend test is not applicable when the specified
wall is 10 % or more of the specified outside diameter, or the wall
thickness is 0.134 in. [3.4 mm] or greater, or the outside diameter size is
less than 0.375 in. [9.5 mm]. Under these conditions the reverse flattening
test of Specification A 1016/A 1016M shall apply.
12. Grain Size Requirement
12.1 The grain size of Grades TP309H, TP309HCb,
TP310H and TP310HCb, as determined in accordance with
Test Methods E 112, shall be No. 6 or coarser.
12.2 The grain size of Grades TP304H, TP316H, TP321H,
TP347H and TP348H, as determined in accordance with Test
Methods E 112, shall be No. 7 or coarser.
13. Mechanical Tests and Grain Size Determinations
13.1 Tension Test—One tension test shall be made on a
specimen for lots of not more than 50 tubes. Tension tests shall
be made on specimens from two tubes for lots of more than 50
tubes (See Note 2).
13.2 Flattening Test—One flattening test shall be made on
specimens from each end of one finished tube, not the one used
for the flange test, from each lot (See Note 1).
13.3 Flange Test—One flange test shall be made on specimens
from each end of one finished tube, not the one used for
the flattening test, from each lot (See Note 1).
13.4 Reverse-Bend Test—One reverse-bend test shall be
made on a specimen from each 1500 ft [450 m] of finished
13.5 Hardness Test—Brinell or Rockwell hardness tests
shall be made on specimens from two tubes from each lot (See
13.6 Hydrostatic or Nondestructive Electric Test—Each
tube shall be subjected to either the hydrostatic or the nondestructive
electric test. The purchaser may specify which test is
to be used.
13.7 Grain Size—Grain size determinations on grades
TP309H, TP309HCb, TP310H and TP310HCb shall be made
on the same number of tubes as prescribed for the flattening
13.8 Heavily cold worked tubes (HCW) shall be capable of
passing the weld decay test listed in Supplementary S7 with a
weld metal to base metal loss ratio of 0.90 to 1.10. The test is
not required unless S7 is specified in the purchase order.
14. Permissible Variations in Dimensions
14.1 Dimensional tolerances other than wall thickness tolerances
shall be in accordance with Specification A 1016/
A 1016M. Wall thickness tolerances shall be 610 % of nominal
wall for all tubing sizes.
14.2 The wall thickness of the weld shall not exceed the
wall thickness measured 90° from the weld by more than 6 %
of the specified wall thickness or 0.004 in. [0.1 mm], whichever
14.2.1 Requirements of 14.2 are not applicable when any of
the following apply:
184.108.40.206 When the specified wall thickness exceeds 12 % of
the specified outside diameter;
220.127.116.11 When the specified wall thickness exceeds 0.165
in. [4.2 mm];
18.104.22.168 When the specified OD exceeds 3 in. [76.2 mm]; or
22.214.171.124 When the specified minimum yield strength given
in Table 4 for the specified grade is 35 ksi [240 MPa] or greater.
15. Workmanship, Finish, and Appearance
15.1 Finished tubes shall have smooth ends free of burrs and
shall not deviate from straightness by more than 0.030 in. [0.8
mm] in 3 ft (900 mm] of length.
16. Surface Condition
16.1 The tubes, after final heat treatment, shall be chemically
descaled or pickled free of scale. When bright annealing
is used, pickling or chemical descaling is not necessary.
17. Forming Operations
17.1 Tubes when inserted in the boiler shall stand expanding
and beading without showing cracks or flaws. All tubes, when
properly manipulated, shall be able to stand expanding and
beading without showing cracks and flaws, and also shall stand
all forging, welding, and bending operations necessary for
application without developing defects.
18. Product Marking
18.1 In addition to the marking prescribed in Specification
A 1016/A 1016M, the marking for Grades TP304H, TP309H,
TP309HCb, TP310H, TP310HCb, TP316H, TP321H, TP347H,
and TP348H shall also include the heat number and the
heat-treatment lot identification.
19.1 austenitic stainless steel; boiler tubes; condenser tube;
heat exchanger tube; high temperature applications; steel tube;
superheater tubes; temperature service applications, high;
welded steel tube and heavily cold worked (HCW) tubes
The following supplementary requirements shall apply only when specified by the purchaser in the
inquiry, contract, or order.
S1. Stress-Relieved Annealed Tubes
S1.1 For use in certain corrosives, particularly chlorides
where stress corrosion may occur, tubes in Grades TP304L,
TP316L, TP321, TP347, and TP348 may be specified in the
stress-relieved annealed condition. Details of these supplemental
requirements shall be agreed upon by the manufacturer and
S1.2 When stress-relieved tubes are specified, tubes shall be
given a heat treatment at 1550 to 1650 °F [845 to 900 °C] after
roll straightening. Cooling from this temperature range may be
either in air or by slow cooling. No mechanical straightening is
permitted after the stress-relief treatment.
S1.3 Straightness of the tubes shall be a matter of negotiation
between the purchaser and manufacturer.
S2. Minimum Wall Tubes
S2.1 When specified by the purchaser, tubes shall be furnished
on a minimum wall basis. Such tubes shall satisfy the
minimum wall thickness requirements of SpecificationA 1016/
A 1016M rather than the nominal wall requirements of this
specification. In addition to the marking required by Section
18, the tubing shall be marked S2.
S3. Air Underwater Pressure Test
S3.1 When specified, the tubing shall be examined by the air
underwater pressure test.
S4. Stabilizing Heat Treatment
S4.1 Subsequent to the solution anneal required in Section
6, Grades TP309HCb, TP310HCb, TP321, TP321H, TP347,
TP347H, TP348, and TP348H shall be given a stabilization
heat treatment at a temperature lower than that used for the
initial solution annealing heat treatment. The temperature of
stabilization heat treatment shall be at a temperature as agreed
upon between the purchaser and vendor.
S5. Unstraightened Tubes
S5.1 When the purchaser specifies tubes unstraightened
after final heat treatment (such as coils), the straightness
requirement of Section 12 shall not apply and the minimum
yield strength of Table 3 shall be reduced by 5 ksi [35 MPa].
S5.2 On the certification, and wherever the grade designation
for unstraightened tubing appears, it shall be identified
with the suffix letter “U” (for example, 304-U, 321-U, etc.).
S6. Intergranular Corrosion Test
S6.1 When specified, material shall pass intergranular corrosion
tests conducted by the manufacturer in accordance with
Practices A 262, Practice E.
NOTE S6.1—Practice E requires testing on the sensitized condition for
low carbon or stabilized grades, and on the as-shipped condition for other
S6.2 A stabilization heat treatment in accordance with
Supplementary Requirement S4 may be necessary and is
permitted in order to meet this requirement for the grades
containing titanium or columbium, particularly in their H
S7. Weld Decay Test
S7.1 This test is not applicable to alloys with a nickel
content $ 19.0 % or a molybdenum content $ 4.00 %, or both.
S7.2 When specified by the purchase order, one sample
from each lot of tubing (See Note 2) shall be subjected to
testing in a boiling mixture of 50 % reagent grade hydrochloric
acid and 50 % water.
S7.3 Approximately 2-in. long samples shall be prepared
from a production length of tubing. Shorter, 1-in. samples may
be used for small diameter (1/2-in. and below) tubing. Split the
sample longitudinally to allow for easy micrometer measurements.
The sample may be one piece which contains the weld
and at least 90° of base-metal to one side of the weld.
Alternately, the sample may be two separate pieces with one
containing the weld and a similar size section from the balance
of the tube opposite the weld consisting of 100 % base metal.
Remove all burrs and sharp edges by lightly grinding. Remove
dust and grease by cleaning with soap and water or other
suitable solvents. Then, place sample(s) in the flask. It is not
recommended to test more than four samples together, or to
mix alloy types.
S7.4 Prepare the hydrochloric acid solution by slowly adding
reagent grade (approximately 37 %) hydrochloric acid to
an equal volume of distilled water. (Warning—Protect eyes
and use rubber gloves when handling acid. Mixing shall be
done under a hood and testing shall be run under a hood.)
S7.5 The test container shall be a 1-L Erlenmeyer flask
equipped with ground-glass joints and an Ahlin condenser. The
volume of the solution shall be approximately 700 mL.
S7.6 Measure the thickness of the tube at five locations
along the weld area and at five locations along the base-metal
section. In both cases, take measurements at approximately
equal longitudinal intervals along the section lengths. Make
these measurements with a sharp pointed micrometer accurate
to at least 0.001 in. The micrometer must be suitable for
measuring the small features in the surface after testing.
Typical pin micrometers have tapered anvils with a tip radius
of less than 0.015 in.
S7.7 Immerse the samples into the solution. Add boiling
chips and bring to a boil. Allow the chips to remain boiling
throughout the test. The time of testing shall be that which is
required to remove 40 to 60 % of the original base-metal
thickness (usually 2 h or less). If more than 60 % of the
base-metal thickness remains, the sample may be removed
after 24 h.
S7.8 At the end of the test period, remove the samples from
the solution, rinse with distilled water, and dry.
S7.9 After exposure to the test solution, repeat the tubethickness
measurement as in S7.6. If the thinning is not
uniform across the width of the weld, then two sets of
weld-metal measurement are required. One set of measurements
is to be taken along the centerline of the weld. The
second set of measurements is to be taken in the thinnest area
of the weld.
S7.10 Calculate the corrosion ratio, R, for both sections of
the weld as follows in Eq 1:
Wo 2 W
Bo 2 B (1)
Wo = average weld-metal thickness before the test,
W = average weld-metal thickness after the test,
Bo = average base-metal thickness before the test, and
B = average base-metal thickness after the test.
S7.10.1 A corrosion ratio of 1.25 or less for the thinnest
section of the weld is permissible. Other criteria, such as a ratio
of 1.00 or less, may be specified upon agreement between the
producer and the purchaser.
S8. Special Applications
S8.1 For special applications, such as hydraulic expansion
of tubes into tube sheets, there shall be no dimensional
indication of the weld. Tubes ordered to this requirement shall
bear the additional marking of NB.
S9. Additional Testing of Welded Tubing per ASME
S9.1 Each tube shall be subjected to an ultrasonic inspection
employing Practices E 273 or E 213 with the rejection criteria
referenced in Specification A 1016/A 1016M.
S9.2 If Practice E 273 is employed, a 100 % volumetric
inspection of the entire length of each tube shall also be
performed using one of the nondestructive electric tests permitted
by Specification A 1016/A 1016M.
S9.3 The test methods described in the supplement may not
be capable of inspecting the end portions of tubes. This
condition is referred to as end effect. This portion, as determined
by the manufacturer, shall be removed and discarded.
S9.4 In addition to the marking prescribed in Specification
A 1016/A 1016M, “S9” shall be added after the grade designation.
Committee A01 has identified the location of selected changes to this specification since the last issue,
A 249/A 249M – 04a, that may impact the use of this specification. (Approved September 1, 2007)
(1) Added UNS 31727 and S32053 to Table 1, Table 2, and