1.1 This specification covers seamless carbon steel pipe for high-temperature service (Note 1) in NPS 1/8 to NPS 48 [DN 6 to DN 1200] (Note 2) inclusive, with nominal (average) wall thickness as given in ASME B 36.10M. It shall be permissible to furnish pipe having other dimensions provided such pipe complies with all other requirements of this specification. Pipe ordered under this specification shall be suitable for bending, flanging, and similar forming operations, and for welding. When the steel is to be welded, it is presupposed that a welding procedure suitable to the grade of steel and intended use or service will be utilized.

NOTE 1—It is suggested, consideration be given to possible graphitization.

NOTE 2—The dimensionless designator NPS (nominal pipe size) [DN (diameter nominal)] has been substituted in this standard for such traditional terms as "nominal diameter," "size," and "nominal size."

1.2 Supplementary requirements of an optional nature are provided for seamless pipe intended for use in applications where a superior grade of pipe is required. These supplementary requirements call for additional tests to be made and when desired shall be so stated in the order.

1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.4 The following precautionary caveat pertains only to the test method portion, Sections 11, 12, and 13 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

3.1 The inclusion of the following, as required will describe the desired material adequately, when ordered under this specification:

1. Quantity (feet, metres, or number of lengths),
2. Name of material (seamless carbon steel pipe),
3. Grade (Table 1),
4. Manufacture (hot-finished or cold-drawn),
5. Size (NPS [DN] and weight class or schedule number, or both; outside diameter and nominal wall thickness; or inside diameter and nominal wall thickness),
6. Special outside diameter tolerance pipe (16.2.2),
7. Inside diameter tolerance pipe, over 10 in. [250 mm] ID (16.2.3),
8. Length (specific or random, Section 17),
9. Optional requirements (S1 to S9),
10. Test report required (Section on Certification of Specification A530/A530M),
11. Specification designation (A106 or A106M, including year-date),
12. End use of material,
13. Hydrostatic test in accordance with Specification A530/A530M or 13.3 of this specification, or NDE in accordance with Section 14 of this specification.
14. Special requirements.

4.1 The steel shall be killed steel, with the primary melting process being open-hearth, basic-oxygen, or electric-furnace, possibly combined with separate degassing or refining. If secondary melting, using electroslag remelting or vacuum-arc remelting is subsequently employed, the heat shall be defined as all of the ingots remelted from a single primary heat.

4.2 Steel cast in ingots or strand cast is permissible. When steels of different grades are sequentially strand cast, identification of the resultant transition material is required. The producer shall remove the transition material by any established procedure that positively separates the grades.

4.3 For pipe NPS 1½ [DN 40] and under, it shall be permissible to furnish hot finished or cold drawn.

4.4 Unless otherwise specified, pipe NPS 2 [DN 50] and over shall be furnished hot finished. When agreed upon between the manufacturer and the purchaser, it is permissible to furnish cold-drawn pipe.

5.1 Hot-finished pipe need not be heat treated. When hot-finished pipe is heat treated, it shall be heat treated at a temperature of 1200 °F [650 °C] or higher.

5.2 Cold-drawn pipe shall be heat treated after the final cold draw pass at a temperature of 1200 °F [650 °C] or higher.

6.1 Material furnished to this specification shall conform to the applicable requirements of the current edition of Specification A530/A530M unless otherwise provided herein.

7.1 The steel shall conform to the requirements as to chemical composition prescribed in Table 1.

8.1 An analysis of each heat of steel shall be made by the steel manufacturer to determine the percentages of the elements specified in Section 7. If the secondary melting processes of 5.1 are employed, the heat analysis shall be obtained from one remelted ingot or the product of one remelted ingot of each primary melt. The chemical composition thus determined, or that determined from a product analysis made by the manufacturer, if the latter has not manufactured the steel, shall be reported to the purchaser or the purchaser's representative, and shall conform to the requirements specified in Section 7.

9.1 At the request of the purchaser, analyses of two pipes from each lot (see 20.1) shall be made by the manufacturer from the finished pipe. The results of these analyses shall be reported to the purchaser or the purchaser's representative and shall conform to the requirements specified in Section 7.

9.2 If the analysis of one of the tests specified in 9.1 does not conform to the requirements specified in Section 7, analyses shall be made on additional pipes of double the original number from the same lot, each of which shall conform to requirements specified.

10.1 The material shall conform to the requirements as to tensile properties given in Table 2.

11.1 For pipe NPS 2 [DN 50] and under, a sufficient length of pipe shall stand being bent cold through 90° around a cylindrical mandrel, the diameter of which is twelve times the outside diameter (as shown in ASME B 36.10M) of the pipe, without developing cracks. When ordered for close coiling, the pipe shall stand being bent cold through 180° around a mandrel, the diameter of which is eight times the outside diameter of the pipe, without failure.

11.2 For pipe over NPS 2 [DN 50] to NPS 4 [DN 100] inclusive, when specified on the order, the pipe shall be capable of being bent cold through 90° around a mandrel having a diameter twelve times the outside diameter of the pipe.

11.3 For pipe NPS 4 [DN 100] and over, when specified on the order, transverse bend tests of the base metal shall be made on specimens from one end of each length of pipe.

14.1 The purchaser may specify that the pipe be subjected to one of the following types of nondestructive examination in place of the hydrostatic test of Section 13:

• 14.1.1 Ultrasonic examination in accordance with Practice E213,
• 14.1.2 Eddy current examination in accordance with Practice E309, or
• 14.1.3 Flux leakage examination in accordance with Practice E570.

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

• 14.2.1 The reference standards defined in 14.4 through 14.6 are convenient standards for calibration of nondestructive testing equipment. The dimensions of such standards are not to be construed as the minimum sizes of imperfections detectable by such equipment.
• 14.2.2 The ultrasonic testing referred to in this specification is capable of detecting the presence and location of significant longitudinally or circumferentially oriented imperfections; however, different techniques need to be employed for the detection of such differently oriented imperfections. Ultrasonic testing is not necessarily capable of detecting short, deep imperfections.
• 14.2.3 The eddy current examination referenced in this specification has the capability of detecting significant imperfections, especially of the short abrupt type.
• 14.2.4 The flux leakage examination referred to in this specification is capable of detecting the presence and location of significant longitudinally or transversely oriented imperfections; however, different techniques need to be employed for the detection of such differently oriented imperfections.
• 14.2.5 The hydrostatic test referred to in Section 13 has the capability of finding defects of a size permitting the test fluid to leak through the tube wall and may be either visually seen or detected by a loss of pressure. Hydrostatic testing is not necessarily capable of detecting very tight, through-the-wall imperfections or imperfections that extend an appreciable distance into the wall without complete penetration.
• 14.2.6 A purchaser interested in ascertaining the nature (type, size, location, and orientation) of discontinuities that can be detected in the specific applications of these examinations is directed to discuss this with the manufacturer of the tubular product.

The mass of any length of pipe shall not vary more than 10% over and 3.5% under that specified. Unless otherwise agreed upon between the manufacturer and the purchaser, pipe in NPS 4 [DN 100] and smaller may be weighed in convenient lots; pipe larger than NPS 4 [DN 100] shall be weighed separately.

Except as provided for thin-wall pipe in paragraph 12.2 of Specification A530/A530M, the tolerances for diameter shall be in accordance with the following:

• 16.2.1 Except for pipe ordered as special outside diameter tolerance pipe or as inside diameter tolerance pipe, variations in outside diameter shall not exceed those given in Table 3.
• 16.2.2 For pipe over 10 in. [250 mm] OD ordered as special outside diameter tolerance pipe, the outside diameter shall not vary more than 1% over or 1% under the specified outside diameter.
• 16.2.3 For pipe over 10 in. [250 mm] ID ordered as inside diameter tolerance pipe, the inside diameter shall not vary more than 1% over or 1% under the specified inside diameter.

The minimum wall thickness at any point shall not be more than 12.5% under the specified wall thickness.

17.1 Pipe lengths shall be in accordance with the following regular practice:

• The lengths required shall be specified in the order, and
• No jointers are permitted unless otherwise specified.
• If definite lengths are not required, pipe may be ordered in single random lengths or in double random lengths meeting the following requirements:
  1. Single random lengths shall be 16 to 22 ft [4.8 to 6.7 m] in length, except that 5% shall be permitted to be less than 16 ft [4.8 m] and none shall be less than 12 ft [3.7 m].
  2. Double random lengths shall have a minimum average length of 35 ft [10.7 m] and shall have a minimum length of 22 ft [6.7 m], except that 5% shall be permitted to be less than 22 ft [6.7 m] and none shall be less than 16 ft [4.8 m].

18.1 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 consideration should be given to the necessity of exploring all surface imperfections to assure compliance with 18.2.

18.2 Surface imperfections that penetrate more than 12½% 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:

1. The defect shall be removed by grinding, provided that the remaining wall thickness is within the limits specified in 16.3.
2. Repaired in accordance with the repair welding provisions of 18.6.
3. The section of pipe containing the defect may be cut off within the limits of requirements on length.
4. Rejected.

18.3 To provide a workmanlike finish and basis for evaluating conformance with 18.2 the pipe manufacturer shall remove by grinding the following noninjurious imperfections:

1. Mechanical marks and abrasions—such as cable marks, dings, guide marks, roll marks, ball scratches, scores, and die marks—and pits, any of which imperfections are deeper than 1/16 in. [1.6 mm].
2. Visual imperfections commonly referred to as scabs, seams, laps, tears, or slivers found by exploration in accordance with 18.1 to be deeper than 5% of the nominal wall thickness.

18.4 At the purchaser's discretion, pipe shall be subjected to rejection if surface imperfections acceptable under 18.2 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.

18.5 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 is permitted to be reduced by the amount so removed.

18.5.1 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.

18.6 Weld repair shall be permitted only subject to the approval of the purchaser and in accordance with Specification A530/A530M.

18.7 The finished pipe shall be reasonably straight.

19.1 The pipe shall be furnished to the following practice, unless otherwise specified:

• 19.1.1 NPS 1½ [DN 40] and Smaller—All walls shall be either plain-end square cut, or plain-end beveled at the option of the manufacturer.
• 19.1.2 NPS 2 [DN 50] and Larger—Walls through extra strong weights, shall be plain-end-beveled.
• 19.1.3 NPS 2 [DN 50] and Larger—Walls over extra strong weights, shall be plain-end square cut.

19.2 Plain-end beveled pipe shall be plain-end pipe having a bevel angle of 30°, +5° or -0°, as measured from a line drawn perpendicular to the axis of the pipe with a root face of 1/16 ± 1/32 in. [1.6 ± 0.8 mm]. Other bevel angles may be specified by agreement between the purchaser and the manufacturer.