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SS pipe grades.

A249/ A249M A269 A270 A778 A335/ A335M A691
A790 A312 A409 A554 A358/ A358M A928/ A928M


CS pipe Grades

A 106 A53 API5L A671 A672

Designation: A 335/A 335M – 06

Standard Specification for
Seamless Ferritic Alloy-Steel Pipe for High-Temperature
Service

This standard is issued under the fixed designation A 335/A 335M; 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. Scope*
1.1 This specification2 covers nominal wall and minimum
wall seamless ferritic alloy-steel pipe intended for hightemperature
service. Pipe ordered to this specification shall be
suitable for bending, flanging (vanstoning), and similar forming
operations, and for fusion welding. Selection will depend
upon design, service conditions, mechanical properties, and
high-temperature characteristics.
1.2 Several grades of ferritic steels (see Note 1) are covered.
Their compositions are given in Table 1.
NOTE 1—Ferritic steels in this specification are defined as low- and
intermediate-alloy steels containing up to and including 10 % chromium.
1.3 Supplementary requirements (S1 to S7) of an optional
nature are provided. These supplementary requirements call for
additional tests to be made, and when desired, shall be so stated
in the order together with the number of such tests required.
1.4 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.
NOTE 2—The dimensionless designator NPS (nominal pipe size) has
been substituted in this standard for such traditional terms as “nominal
diameter,” “size,” and “nominal size.”

2. Referenced Documents
2.1 ASTM Standards: 3

1 This specification is under the jurisdiction of ASTM Committee A01 on Steel,
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
A01.10 on Stainless and Alloy Steel Tubular Products.
Current edition approved May 1, 2006. Published May 2006. Originally
approved in 1951. Last previous edition approved in 2005 as A 335/A 335M-05a.
2 For ASME Boiler and Pressure Vessel Code applications see related Specification
SA-335 in Section II of that Code.
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
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.

A 999/A 999M Specification for General Requirements for
Alloy and Stainless Steel Pipe
E 213 Practice for Ultrasonic Examination of Metal Pipe
and Tubing
E 309 Practice for Eddy-Current Examination of Steel Tubular
Products Using Magnetic Saturation
E 381 Method of Macroetch Testing Steel Bars, Billets,
Blooms, and Forgings
E 527 Practice for Numbering Metals and Alloys (UNS)
E 570 Practice for Flux Leakage Examination of Ferromagnetic
Steel Tubular Products
2.2 ASME Standard:
B36.10M Welded and Seamless Wrought Steel Pipe
2.3 Other Documents:
SNT-TC-1A Recommended Practice for Nondestructive
Personnel Qualification and Certification4
SAE J 1086 Practice for Numbering Metals and Alloys
(UNS)5
3. Ordering Information
3.1 Orders for material under this specification should
include the following, as required, to describe the desired
material adequately:
3.1.1 Quantity (feet, metres, or number of lengths),
3.1.2 Name of material (seamless alloy steel pipe),
3.1.3 Grade (Table 1),
3.1.4 Manufacture (hot-finished or cold-drawn),
3.1.5 Size using one of the following:
3.1.5.1 NPS and schedule number,
3.1.5.2 Outside diameter and nominal wall thickness,
3.1.5.3 Outside diameter and minimum wall thickness,
3.1.5.4 Inside diameter and nominal wall thickness, and
3.1.5.5 Inside diameter and minimum wall thickness.
3.1.6 Length (specific or random),
3.1.7 End finish (Ends Section of Specification A 999/
A 999M),

4 Available from The American Society for Nondestructive Testing (ASNT), P.O.
Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518.
5 Available from Society of Automotive Engineers (SAE), 400 Commonwealth
Dr., Warrendale, PA 15096-0001.

3.1.8 Optional requirements (Section 8, 12 and 13 of this
specification. See the Sections on Hydrostatic Test Requirements
and Permissible Variation inWeight for Seamless Pipe in
Specification A 999/A 999M),
3.1.9 Test report required (Certification Section of Specification
A 999/A 999M),
3.1.10 Specification designation, and
3.1.11 Special requirements or any supplementary requirements
selected, or both.

4. General Requirements
4.1 Material furnished to this specification shall conform to
the applicable requirements of the current edition of Specification
A 999/A 999M, unless otherwise provided herein.

5. Materials and Manufacture
5.1 Pipe may be either hot finished or cold drawn with the
finishing treatment as required in 5.3.
5.2 Grade P2 and P12—The steel shall be made by coarsegrain
melting practice. Specific limits, if any, on grain size or
deoxidation practice shall be a matter of agreement between
the manufacturer and purchaser.
5.3 Heat Treatment:
5.3.1 All pipe shall be reheated for heat treatment and heat
treated in accordance with the requirements of Table 2.
NOTE 3—It is recommended that the temperature for tempering should
be at least 100 °F [50 °C] above the intended service temperature;
consequently, the purchaser should advise the manufacturer if the service
temperature is to be over 1100 °F [600 °C].
NOTE 4—Certain of the ferritic steels covered by this specification will
harden if cooled rapidly from above their critical temperature. Some will
air harden, that is, become hardened to an undesirable degree when cooled
in air from high temperatures. Therefore, operations involving heating
such steels above their critical temperatures, such as welding, flanging,
and hot bending, should be followed by suitable heat treatment.

6. Chemical Composition
6.1 The steel shall conform to the requirements as to
chemical composition prescribed in Table 1.

7. Workmanship, Finish, and Appearance
7.1 The pipe manufacturer shall explore a sufficient number
of visual surface imperfections to provide reasonable assurance
that they have been properly evaluated with respect to depth.
Exploration of all surface imperfections is not required but may
be necessary to ensure compliance with 7.2
7.2 Surface imperfections that penetrate more than 121⁄2 %
of the nominal wall thickness or encroach on the minimum
wall thickness shall be considered defects. Pipe with such
defects shall be given one of the following dispositions:
7.2.1 The defect may be removed by grinding provided that
the remaining wall thickness is within specified limits.
7.2.2 Repaired in accordance with the repair welding provisions
of 7.6.
7.2.3 The section of pipe containing the defect may be cut
off within the limits of requirements on length.
7.2.4 Rejected.
7.3 To provide a workmanlike finish and basis for evaluating
conformance with 7.2, the pipe manufacturer shall remove
by grinding the following:
7.3.1 Mechanical marks, abrasions (see Note 5) and pits,
any of which imperfections are deeper than 1⁄16 in. [1.6 mm].

TABLE 2 Heat Treatment RequirementsA

Grade

Heat Treat Type

Normalizing Temperature, min or range
°F [°C]

Cooling Media

Subcritical Annealing or Tempering Temperature, min or range
°F [°C]

P1

full or isothermal anneal

. . .

. . .

. . .

 

normalize and temper

. . .

. . .

1200 [650]

 

subcritical anneal

. . .

. . .

1200-1300 [650-705]

P2

full or isothermal anneal

. . .

. . .

. . .

 

normalize and temper

. . .

. . .

1250 [675]

 

subcritical anneal

. . .

. . .

1200-1300 [650-705]

P5

full or isothermal anneal

. . .

. . .

. . .

 

normalize and temper

. . .

. . .

1250 [675]

P5b

full or isothermal anneal

. . .

. . .

. . .

 

normalize and temper

. . .

. . .

1250 [675]

P5c

subcritical anneal

. . .

. . .

1325-1375 [715-745]

P9

full or isothermal anneal

. . .

. . .

. . .

 

normalize and temper

. . .

. . .

1250 [675]

P11

full or isothermal anneal

. . .

. . .

. . .

 

normalize and temper

. . .

. . .

1200 [650]

P12

full or isothermal anneal

. . .

. . .

. . .

 

normalize and temper

. . .

. . .

1200 [650]

 

subcritical anneal

. . .

. . .

1200-1300 [650-705]

P15

full or isothermal anneal

. . .

. . .

. . .

 

normalize and temper

. . .

. . .

1200 [650]

P21

full or isothermal anneal

. . .

. . .

. . .

 

normalize and temper

. . .

. . .

1250 [675]

P22

full or isothermal anneal

. . .

. . .

. . .

 

normalize and temper

. . .

. . .

1250 [675]

P23

normalize and temper

1900-1975 [1040-1080]

air or

1350-1470 [730-800]

 

 

 

accelerated

 

 

P36

 

normalize and temperB

 

1650 [900]

cooling
. . .

 

1100 [595]

P91

normalize and temper

1900-1975 [1040-1080]

. . .

1350-1470 [730-800]C

 

quench and temperD

1900-1975 [1040-1080]

. . .

1350-1470 [730-800]

P92

normalize and temper

1900-1975 [1040-1080]

. . .

1350-1470 [730-800]

P122

normalize and temper

1900-1975 [1040-1080]

. . .

1350-1470 [730-800]

P911                           normalize and temper                         1900-1975 [1040-1080]                                  E                                                         1365-1435 [740-780]

AWhere ellipses (…) appear in this table there is no requirement.
BAlternatively, Grade P36, Class 2 shall be cooled from the austenitizing temperature by accelerated cooling in air or by liquid quenching.
CExcept when Supplementary Requirement S7 is specified by the purchaser.
D When mutually agreed upon between the manufacturer and the purchaser, quenching and tempering shall be permitted for thicknesses greater than 3 in. [75 mm].
E Accelerated cooling from the normalizing temperature shall be permitted for section thicknesses greater than 3 in. [75 mm].

NOTE 5—Marks and abrasions are defined as cable marks, dinges, guide
marks, roll marks, ball scratches, scores, die marks, and the like.
7.3.2 Visual imperfections, commonly referred to as scabs,
seams, laps, tears, or slivers, found by exploration in accordance
with 7.1 to be deeper than 5 % of the nominal wall
thickness.
7.4 At the purchaser’s discretion, pipe shall be subject to
rejection if surface imperfections acceptable under 7.2 are not
scattered, but appear over a large area in excess of what is
considered a workmanlike finish. Disposition of such pipe shall
be a matter of agreement between the manufacturer and the
purchaser.
7.5 When imperfections or defects are removed by grinding,
a smooth curved surface shall be maintained, and the wall
thickness shall not be decreased below that permitted by this
specification. The outside diameter at the point of grinding may
be reduced by the amount so removed.
7.5.1 Wall thickness measurements shall be made with a
mechanical caliper or with a properly calibrated nondestructive
testing device of appropriate accuracy. In case of dispute, the
measurement determined by use of the mechanical caliper shall
govern.
7.6 Weld repair shall be permitted only subject to the
approval of the purchaser and in accordance with Specification
A 999/A 999M.
7.6.1 After weld repair, Grades P23, P91, P92, and P122
shall be heat treated at 1350-1470 ºF [730-800 ºC].
7.6.2 After weld repair, Grade P911 shall be heat treated at
1365-1435 ºF [740-780 ºC].
7.7 The finished pipe shall be reasonably straight.8. Product Analysis
8.1 At the request of the purchaser, an analysis of two pipes
from each lot shall be made by the manufacturer. A lot (see
Note 6) of pipe shall consist of the following:

NPS Designator
Under 2                                                        400 or fraction thereof
2 to 5                                                           200 or fraction thereof
6 and over                                                   100 or fraction thereof

NOTE 6—A lot shall consist of the number of lengths specified in 8.1 of
the same size and wall thickness from any one heat of steel.
8.2 The results of these analyses shall be reported to the
purchaser or the purchaser’s representative, and shall conform
to the requirements specified in Table 1.
8.3 For grade P 91 the carbon content may vary for the
product analysis by −0.01 % and +0.02 % from the specified
range as per Table 1.

8.4 If the analysis of one of the tests specified in 8.1 does
not conform to the requirements specified in 6.1, an analysis of
each billet or pipe from the same heat or lot may be made, and
all billets or pipe conforming to the requirements shall be
accepted.
9. Tensile and Hardness Requirements
9.1 The tensile properties of the material shall conform to
the requirements prescribed in Table 3.
9.2 Table 4 lists elongation requirements.
9.3 Pipe of Grades P91, P92, P122, and P36 shall have a
hardness not exceeding 250 HB/265 HV [25 HRC].
9.4 Table 5 gives the computed minimum elongation values
for each 1⁄32-in. [0.8-mm] decrease in wall thickness. Where the
wall thickness lies between two values above, the minimum
elongation value is determined by the following formula:
Direction of Test EquationB
Longitudinal, all grades except P23, P91,
P92, P122, and P911
E = 48t + 15.00
[E = 1.87t + 15.00]
Transverse, all grades except P23, P91,
P92, P122, and P911
E = 32t + 10.00
[E = 1.25t + 10.00]
Longitudinal, P23, P91, P92, P122, and
P911
E = 32t + 10.00
[E = 1.25t + 10.00]
Longitudinal, P36 E = 32t + 5.0
[E = 1.25t + 5.0]
where:
E = elongation in 2 in. or 50 mm, %, and
t = actual thickness of specimens, in. [mm].
10. Permissible Variations in Diameter
10.1 For pipe ordered to NPS [DN] or outside diameter,
variations in outside diameter shall not exceed those specified
in Table 6.
10.2 For pipe ordered to inside diameter, the inside diameter
shall not vary more than 6 1 % from the specified inside
diameter.
11. Permissible Variations in Wall Thickness
11.1 In addition to the implicit limitation of wall thickness
for pipe imposed by the limitation on weight in Specification
A 999/A 999M, the wall thickness for pipe at any point shall be
within the tolerances specified in Table 7. The minimum wall
thickness and outside diameter for inspection for compliance
with this requirement for pipe ordered by NPS [DN] and
schedule number is shown in ASME B36.10M.
12. Hydrostatic Test
12.1 Each length of pipe shall be subjected to the hydrostatic
test, except as provided for in 12.2 or 12.3.

12.2 Unless otherwise specified in the purchase order, each
length of pipe shall, at the option of the manufacturer, be
subjected to the nondestructive electric test as shown in Section
13 in lieu of the hydrostatic test.
12.3 When specified by the purchaser, pipe shall be furnished
without hydrostatic test and without nondestructive
examination.
12.4 When specified by the purchaser, pipe shall be furnished
with both the hydrostatic test and a nondestructive
examination having been performed.
13. Nondestructive Examination
13.1 When selected by the manufacturer or when specified
in the order, as an alternative to the hydrostatic test (12.2), or
when specified in the purchase order in addition to the
hydrostatic test (12.4), each pipe shall be examined by a
nondestructive examination method in accordance with Practice
E 213, Practice E 309 or Practice E 570. The range of pipe
sizes that may be examined by each method shall be subject to
the limitations in the scope of the respective practices.
13.2 The following information is for the benefit of the user
of this specification:
13.2.1 The reference standards defined in 13.8 are convenient
standards for standardization of nondestructive examination
equipment. The dimensions of these standards should not
be construed as the minimum size imperfection detectable by
such equipment.
13.2.2 Ultrasonic examination can be performed to detect
both longitudinally and transversely oriented discontinuities. It
should be recognized that different techniques should be
employed to detect differently oriented imperfections. The
examination may not detect short, deep imperfections.

13.2.3 The eddy current examination referenced in this
specification has the capability to detect significant discontinuities,
especially of the short abrupt type.
13.2.4 The flux leakage examination referred to in this
specification is capable of detecting the presence and location
of significant longitudinally or transversely oriented discontinuities.
It should be recognized that different techniques should
be employed to detect differently oriented imperfections.
13.2.5 The hydrostatic test of Section 12 has the capability
to find imperfections of a size that permit the test fluid to leak
through the pipe wall so that it may be either visually seen or
detected by a loss of fluid pressure. This test may not detect
very tight, through-wall imperfections, or imperfections that
extend into the wall without complete penetration.
13.2.6 A purchaser interested in ascertaining the nature
(type, size, location, and orientation) of discontinuities that can
be detected in the specific application of these examinations
should discuss this with the manufacturer of the tubular
products.
13.3 Time of Examination:
Nondestructive examination for specification acceptance
shall be performed after all mechanical processing, heat
treatments and straightening operations. This requirement does
not preclude additional testing at earlier stages in the processing.
13.4 Surface Conditions:
13.4.1 All surfaces shall be clean and free of scale, dirt,
grease, paint, or other foreign material that could interfere with
interpretation of test results. The methods used for cleaning
and preparing the surfaces for examination shall not be
detrimental to the base metal or the surface finish.
13.4.2 Excessive surface roughness or deep scratches can
produce signals that interfere with the test (see 13.10.2.3).
13.5 Extent of Examination:
13.5.1 The relative motion of the pipe and the transducer(s),
coil(s), or sensor(s) shall be such that the entire pipe surface is
scanned, except for end effects as noted in 13.5.2.
13.5.2 The existence of end effects is recognized, and the
extent of such effects shall be determined by the manufacturer,
and, if requested, shall be reported to the purchaser. Other
nondestructive tests may be applied to the end areas, subject to
agreement between the purchaser and the manufacturer.
13.6 Operator Qualifications—The test unit operator shall
be certified in accordance with SNT-TC-1A, or an equivalent,
recognized and documented standard.
13.7 Test Conditions:
13.7.1 For examination by the ultrasonic method, the minimum
nominal transducer frequency shall be 2.25 MHz.
13.7.2 For eddy current testing, the excitation coil frequency
shall be 10 kHz, or less.
13.8 Reference Standards:
13.8.1 Reference standards of convenient length shall be
prepared from a length of pipe of the same grade, size (NPS or
outside diameter and schedule or wall thickness), surface finish
and heat treatment condition as the pipe to be examined.
13.8.2 For ultrasonic testing, the reference notches shall be
any one of the three common notch shapes shown in Practice
E 213, at the option of the manufacturer. The depth of the notchshall not exceed 121⁄2 % of the specified nominal wall
thickness of the pipe or 0.004 in. (0.1 mm), whichever is
greater. The length of the notch shall be at least twice the
diameter of the transducer(s). The width of the notch shall not
exceed the depth.
13.8.3 For eddy current testing, the reference standard shall
contain, at the option of the manufacturer, any one of the
following discontinuities:
13.8.3.1 Drilled Hole—The reference standard shall contain
three or more holes, equally spaced circumferentially around
the pipe and longitudinally separated by a sufficient distance to
allow distinct identification of the signal from each hole. The
holes shall be drilled radially and completely through the pipe
wall, with care being taken to avoid distortion of the pipe while
drilling. The hole diameter shall vary with NPS as follows:

13.8.3.2 Transverse Tangential Notch—Using a round tool
or file with a 1⁄4 in. (6.4 mm) diameter, a notch shall be filed
or milled tangential to the surface and transverse to the
longitudinal axis of the pipe. Said notch shall have a depth not
exceeding 121⁄2 % of the specified nominal wall thickness of
the pipe or 0.004 in. (0.1 mm), whichever is greater.
13.8.3.3 Longitudinal Notch—A notch 0.031 in. or less in
width shall be machined in a radial plane parallel to the tube
axis on the outside surface of the pipe, to have a depth not
exceeding 121⁄2 % of the specified nominal wall thickness of
the pipe or 0.004 in. (0.1 mm), whichever is greater. The length
of the notch shall be compatible with the testing method.
13.8.4 For flux leakage testing, the longitudinal reference
notches shall be straight-sided notches machined in a radial
plane parallel to the pipe axis. For wall thickness less than 1⁄2
in. (12.7 mm), outside and inside notches shall be used; for
wall thicknesses equal to or greater than 1⁄2 in., only an outside
notch shall be used. Notch depth shall not exceed 121⁄2 % of
the specified nominal wall thickness or 0.004 in. (0.1 mm),
whichever is greater. Notch length shall not exceed 1 in. (25.4
mm), and the width shall not exceed the depth. Outside and
inside notches shall have sufficient separation to allow distinct
identification of the signal from each notch.
13.8.5 More or smaller reference discontinuities, or both,
may be used by agreement between the purchaser and the
manufacturer.
13.9 Standardization Procedure:
13.9.1 The test apparatus shall be standardized at the
beginning and end of each series of pipes of the same size
(NPS or diameter and schedule or wall thickness), grade and
heat treatment condition, and at intervals not exceeding 4 h

during the examination of such pipe. More frequent standardizations
may be performed at the manufacturer’s option or may
be required upon agreement between the purchaser and the
manufacturer.
13.9.2 The test apparatus shall also be standardized after
any change in test system settings, change of operator, equipment
repair, or interruption due to power loss, shutdown or
operator breaks.
13.9.3 The reference standard shall be passed through the
test apparatus at same speed and test system settings as the pipe
to be tested.
13.9.4 The signal-to-noise ratio for the reference standard
shall be 2.5 to 1 or greater and the reference signal amplitude
for each discontinuity shall be at least 50 % of full scale of the
display.
13.9.5 If upon any standardization, the reference signal
amplitude has decreased by 25 % (2 db), the test apparatus
shall be considered out of standardization. The test system
settings may be changed, or the transducer(s), coil(s) or
sensor(s) adjusted, and the unit restandardized, but all pipe
tested since the last acceptable standardization must be retested.
13.10 Evaluation of Imperfections:
13.10.1 Pipes producing a signal equal to or greater than the
signal produced by the reference standard shall be positively
identified and they shall be separated from the acceptable
pipes. The area producing the signal may be reexamined.
13.10.2 Such pipes shall be subject to one of the following
three dispositions:
13.10.2.1 The pipes may be rejected without further examination,
at the discretion of the manufacturer.
13.10.2.2 The pipes shall be rejected, but may be repaired,
if the test signal was produced by imperfections which cannot
be identified, or was produced by cracks or crack-like imperfections.
These pipes may be repaired by grinding (in accordance
with 7.2.1), welding (in accordance with 7.6) or sectioning
(in accordance with 7.2.3). To be accepted, a repaired pipe
must pass the same nondestructive examination by which it
was rejected, and it must meet the remaining wall thickness
requirements of this specification.
13.10.2.3 Such pipes may be evaluated in accordance with
the provisions of Section 7, if the test signals were produced by
visual imperfections such as those listed below:
(1) Scratches,
(2) Surface roughness,
(3) Dings,
(4) Straightener marks,
(5) Cutting chips,
(6) Steel die stamps,
(7) Stop marks, or
(8) Pipe reducer ripple.
14. Mechanical Tests Required
14.1 Transverse or Longitudinal Tension Test and Flattening
Test, Hardness Test, or Bend Test—For material heat
treated in a batch-type furnace, tests shall be made on 5 % of
the pipe from each treated lot (see Note 7). For small lots, at
least 1 pipe shall be tested. For material heat treated by the

continuous process, tests shall be made on a sufficient number
of pipe to constitute 5 % of the lot (see Note 7), but in no case
less than 2 pipe.
NOTE 7—The term “lot” applies to all pipe of the same nominal size
and wall thickness (or schedule) which is produced from the same heat of
steel and subjected to the same finishing treatment in a continuous
furnace; when final heat treatment is in a batch-type furnace, the lot shall
include only that pipe which is heat treated in the same furnace charge.
14.2 Hardness Test:
14.2.1 For pipe of Grades P91, P92, P122, P911, and P36,
Brinell, Vickers, or Rockwell hardness tests shall be made on
a specimen from each lot (see Note 7).
14.3 Bend Test:
14.3.1 For pipe whose diameter exceeds NPS 25 and whose
diameter to wall thickness ratio is 7.0 or less shall be subjected
to the bend test instead of the flattening test. Other pipe whose
diameter equals or exceeds NPS 10 may be given the bend test
in place of the flattening test subject to the approval of the
purchaser.
14.3.2 The bend test specimens shall be bent at room
temperature through 180° without cracking on the outside of
the bent portion. The inside diameter of the bend shall be 1 in.
[25 mm].
14.3.3 Test specimens for the bend test specified in 14.3
shall be cut from one end of the pipe and, unless otherwise
specified, shall be taken in a transverse direction. One test
specimen shall be taken as close to the outer surface as possible
and another from as close to the inner surface as possible. The
specimens shall be either 1⁄2 by 1⁄2 in. [12.5 by 12.5 mm] in
section or 1 by 1⁄2 in. [25 by 12.5 mm] in section with the
corners rounded to a radius not over 1⁄16 in. [1.6 mm] and need
not exceed 6 in. [150 mm] in length. The side of the samples
placed in tension during the bend shall be the side closest to the
inner and outer surface of the pipe, respectively.
15. Certification
15.1 In addition to the information required by Specification
A 999/A 999M, the certification shall state whether or not the
pipe was hydrostatically tested. If the pipe was nondestructively
examined, the certification shall so state and shall show
which practice was followed and what reference discontinuities
were used. In addition, the test method information as given in
Table 8 shall be appended to the specification number and
grade shown on the certification.
16. Product Marking
16.1 In addition to the marking prescribed in Specification
A 999/A 999M, the marking shall include the length, an
additional symbol “S”, if the pipe conforms to any of the
Supplementary Requirements S1 to S6, the schedule number, if
the pipe is ordered to a schedule number, and the heat number

TABLE 8   Test Method Information for Certification and Marking

Hydrostatic

Nondestructive

Marking

YES NO NO YES

NO YES NO YES

Test Pressure
NDE NH
Test Pressure/NDE

or manufacturer’s number by which the heat can be identified.
Furthermore, the marking designated in Table 8 to indicate the
test method(s) shall be included. Marking may be by stenciling,
stamping, or rolling. Pipe that has been weld repaired in
accordance with 7.6 shall be marked “WR.”
17. Government Procurement
17.1 Scale Free Pipe:
17.1.1 When specified in the contract or order, the following
requirements shall be considered in the inquiry contract or
order, for agencies of the U.S. Government where scale free
pipe is required. These requirements shall take precedence if
there is a conflict between these requirements and the product
specification.
17.1.2 The requirements of Specification A 999/A 999M for
pipe shall be applicable when pipe is ordered to this specification.
17.1.3 Pipe shall be one of the following grades as specified
herein:

Grade                                             UNS Designation
P11                                                       K11597
P22                                                       K21590
P5                                                        K41545

17.1.4 Part Number:
17.1.4.1 Pipe shall be ordered to nominal pipe size and
schedule specified in ASME B36.10M
Example: A 335/A 335M Pipe P-11 NPS 12 Sch 40

Specification Number                                      ASTM A 335/A 335M Pipe                                                                  P
Grade                                                               P-11
NPS                                                                 12
Wall                                                                  0.375

17.1.4.2
Specification Number                                      ASTM A 335/A 335 M Tube                                                               
Grade                                                               P-11
Outside Diameter                                             0.250
Wall                                                                  0.035

17.1.5 Ordering Information—Orders for material under
this specification shall include the following in addition to the
requirements of Section 3:
17.1.5.1 Pipe or tube,
17.1.5.2 Part number,
17.1.5.3 Ultrasonic inspection, if required,
17.1.5.4 If shear wave test is to be conducted in two
opposite circumferential directions, and
17.1.5.5 Level of preservation and packing required.
18. Keywords
18.1 alloy steel pipe; high temperature service; seamless
steel pipe; steel pipe; temperature service applications

SUPPLEMENTARY REQUIREMENTS

One or more of the following supplementary requirements shall apply only when specified in the
purchase order. The purchaser may specify a different frequency of test or analysis than is provided
in the supplementary requirement. Subject to agreement between the purchaser and manufacturer,
retest and retreatment provisions of these supplementary requirements may also be modified.

S1. Product Analysis
S1.1 Product analysis shall be made on each length of pipe.
Individual lengths failing to conform to the chemical composition
requirements shall be rejected.
S2. Transverse Tension Tests
S2.1 A transverse tension test shall be made on a specimen
from one end or both ends of each pipe NPS 8 and over. If this
supplementary requirement is specified, the number of tests per
pipe shall also be specified. If a specimen from any length fails
to meet the required tensile properties (tensile, yield, and
elongation), that length shall be rejected subject to retreatment
in accordance with Specification A 999/A 999M and satisfactory
retest.
S3. Flattening Test
S3.1 The flattening test of Specification A 999/A 999M
shall be made on a specimen from one end or both ends of each
pipe. Crop ends may be used. If this supplementary requirement
is specified, the number of tests per pipe shall also be
specified. If a specimen from any length fails because of lack
of ductility prior to satisfactory completion of the first step of
the flattening test requirement, that pipe shall be rejected
subject to retreatment in accordance with Specification A 999/
A 999M and satisfactory retest. If a specimen from any length
of pipe fails because of a lack of soundness that length shall be
rejected, unless subsequent retesting indicates that the remaining
length is sound. The bend test of 13.2 shall be substituted
for the flattening test for pipe whose diameter exceeds NPS 25
and whose diameter to wall thickness ratio is 7.0 or less.
S4. Metal Structure and Etching Tests
S4.1 The steel shall be homogeneous as shown by etching
tests conducted in accordance with the appropriate portions of
Method E 381. Etching tests shall be made on a cross section
from one end or both ends of each pipe and shall show sound
and reasonably uniform material free from injurious laminations,
cracks, and similar objectionable defects. If this supplementary
requirement is specified, the number of tests per pipe
required shall also be specified. If a specimen from any length

shows objectionable defects, the length shall be rejected,
subject to removal of the defective end and subsequent retests
indicating the remainder of the length to be sound and
reasonably uniform material.
NOTE S4.1—Pending development of etching methods applicable to the
product covered by this specification, it is recommended that the Recommended
Practice for a Standard Macro Etch Test for Routine Inspection of
Iron and Steel, described in the Metals Handbook, Am. Soc. for Metals,
1948 edition, p. 389, be followed.
S5. Photomicrographs
S5.1 When requested by the purchaser and so stated in the
order, the manufacturer shall furnish one photomicrograph at
100 diameters from a specimen of pipe in the as-finished
condition for each individual size and wall thickness from each
heat, for pipe NPS 3 and over. Such photomicrographs shall be
suitably identified as to pipe size, wall thickness, and heat. No
photomicrographs for the individual pieces purchased shall be
required except as specified in Supplementary Requirement S6.
Such photomicrographs are for information only, to show the
actual metal structure of the pipe as finished.
S6. Photomicrographs for Individual Pieces
S6.1 In addition to the photomicrographs required in accordance
with Supplementary Requirement S5, the purchaser may
specify that photomicrographs shall be furnished from each
end of one or more pipes from each lot of pipe NPS 3 and
larger in the as-finished condition. The purchaser shall state in
the order the number of pipes to be tested from each lot. When
photomicrographs are required on each length, the photomicrographs
from each lot of pipe in the as-finished condition
which may be required under Supplementary Requirement S5
may be omitted. All photo-micrographs required shall be
properly identified as to heat number, size, and wall thickness
of pipe from which the section was taken. Photomicrographs
shall be further identified to permit association of each photomicrograph
with the individual length of pipe it represents.
S7. Alternative Heat Treatment—Grade P91
S7.1 Grade P91 shall be normalized in accordance with
Table 2 and tempered at a temperature, to be specified by the
purchaser, less than 1350 °F [730 °C]. It shall be purchaser’s
responsibility to subsequently temper at 1350-1470 °F [730-
800 °C] minimum. All mechanical tests shall be made on
material heat treated in accordance with Table 2. The certification
shall reference this supplementary requirement indicating
the tempering temperature applied. The notation “S7” shall
be included with the required marking of the pipe.

SUMMARY OF CHANGES

Committee A01 has identified the location of selected changes to this specification since the last issue,
A 335/A 335M-05a, that may impact the use of this specification. (Approved May 1, 2006)

(1) Reduced Cr maximum for Grade 122 in Table 1.
(2) Reduce Al maximum and added maximums for Ti and Zr
for Grades P91, P92, P122, and P911 in Table 1.

Committee A01 has identified the location of selected changes to this specification since the last issue,
A 335/A 335M-05, that may impact the use of this specification. (Approved May 1, 2005)

(1) Revised Table 1, Table 3, Table 4, and Table 5 and modified
9.3 and 13.2.1 to provide for new grade P36, Classes 1 and 2.
(2) Revised 5.3, Supplementary Requirement S7, and added
Table 2, to tabularize the heat treatment requirements and to
provide ranges of normalizing and tempering temperatures for
Grades P23, P91, P92, P911, and P122. Added permission to
use quenching and tempering for P911 over 3 in. [75mm] in
thickness.
(3) Added 7.6.1 and 7.6.2 to require post-weld heat treatment
(PWHT) after weld repair, and to specify temperature ranges
for PWHT, for Grades P23, P91, P92, P911, and P122.

Committee A01 has identified the location of selected changes to this specification since the last issue,
A 335/A 335M-03, that may impact the use of this specification. (Approved March 1, 2005)

(1) Added ASME B36.10M to Referenced Documents and
corrected the reference from ANSI B36.10 to ASME B36.10M
in 17.1.4.1.
(2) Revised Chromium content of Grade P911 in Table 1.
(3) Added DN SI-unit designator to 10.1 and Table 6.
(4) Added new Section 11 and Table 7 to address maximum
wall thickness of pipe and renumbered subsequent paragraphs
and tables accordingly.