ASTM A335 P91 Pipe , Seamless Carbon Steel Pipe For High Temperature Service

Product Specification

ASTM A335 P91 seamless alloy steel boiler pipe for high temperature service

Seamless alloy steel pipe for high temperature service

Ordering Information

Orders for material under this specification should include the following, as required, to describe the desired material adequately:

1 Quantity (feet, centimetres, or number of lengths),

2 Name of material (seamless alloy steel pipe),

3 Grade,

4 Manufacture (hot-finished or cold-drawn),

5 Size (NPS or outside diameter and schedule number or average wall thickness),

6 Length (specific or random),

7 End finish (Ends Section of Specification A 999/A 999M),

8 Optional requirements (Section 8, 11 and 12 of specification ASTM A335. See the Sections on Hydrostatic Test Requirements and Permissible Variation in Weight for Seamless Pipe in Specification A 999/A 999M),

9 Test report required (Certification Section of Specification AA 999/A 999M),

10 Specification designation, and

11 Special requirements or any supplementary requirements selected, or both.

Materials and Manufacture

1 Pipe may be either hot finished or cold drawn with the finishing treatment as required in 3.

2 Grade P12—The steel shall be made by coarse grain melting practice. Specific limits, if any, on grain size or deoxidation practice shall be a matter of agreement between the manufacturer and purchaser.

3 Heat Treatment:

3.1 All pipe of grades except P5, P91, P92, shall be reheated and furnished in the full-annealed, isothermal annealed, or normalized and tempered condition. If furnished in the normalized and tempered condition, the minimum tempering temperature for Grades P5, P5b, P9, P21, and P22 shall be 1250°F [675°C], the minimum tempering temperature for Grades P1, P2, P11, P12, and P 15 shall be 1200°F [650°C].

NOTE—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].

3.2 Pipe of Grades P12, either hot finished or cold drawn, may be given a final heat treatment at 1200°F [650°C] to 1300°F [705°C] instead of heat treatments specified in 3.1.

3.3 All pipe of Grades P5c shall be given a final heat treatment in the range from 1325°F [715°C] to 1375°F [745°C].

NOTE—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.

3.4 Grade T92 shall be normalized at 1900°F [1040°C] minimum and tempered at 1350°F [730°C] minimum as a final heat treatment.

5.4 Except when Supplementary Requirement S7 is specified by the purchaser, Grade P91 shall be normalized at 1900°F [1040°C] minimum, and tempered at 1350°F [730°C] minimum as a final heat treatment. Alternatively, liquid quenching and tempering is allowed for thicknesses above 3 in. when mutually agreed upon between the manufacturer and the purchaser. In this case the pipe shall be quenched from 1900°F [1040°C] minimum and tempered at 1350°F [730°C] minimum as final heat treatment.

Chemical composition, %

Tensile requirements

Elongation requirements

Hydrostatic Test

1 Each length of pipe shall be subjected to the hydrostatic hydrostatic test, except as provided for in 2 or 3.

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 12 of ASTM A335 in lieu of the hydrostatic test.

3 When specified by the purchaser, pipe shall be furnished without hydrostatic test and without nondestructive examination.

4 When specified by the purchaser, pipe shall be furnished with both the hydrostatic test and a nondestructive examination having been performed.

Nondestructive Examination

1 When selected by the manufacturer or when specified in the order, as an alternative to the hydrostatic test, or when specified in the purchase order in addition to the hydrostatic test, 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.

2 The following information is for the benefit of the user of this specification:

2.1 The reference standards defined in 12.8 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.

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.

2.3 The eddy current examination referenced in this specification has the capability to detect significant discontinuities, especially of the short abrupt type.

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.

2.5 The hydrostatic test of Section 11 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.

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.

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.

4 Surface Conditions:

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.

4.2 Excessive surface roughness or deep scratches can produce signals that interfere with the test

Mechanical tests required

Transverse or longitudinal tension test

Flattening test

Hardness test

Bend test

Product Marking

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 ANSI schedule number and the heat number or manufacturer’s number by which the heat can be identified. Furthermore, the marking designated in Table 6 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 in ASTM A335 shall be marked “WR.”

Seamless Pipe Specifications

Standard : ASTM A335 / ASME SA335

Outside Diameter: 325-1067 mm

Wall Thickness: 9.53-140 mm

Length: On the request

Production procedure