ASTM A369 Standard Specification

/ A369M – Specification for Carbon and Ferritic Alloy Steel Forged and Bored Pipe for High-Temperature Service

Seamless tube process

First, a red-hot stainless steel forged hollow rod is formed with a pilger. After the bar has cooled, the tube is cold drawn through a die, and if needed over a plug or mandrel for further sizing.

ASTM A369 standard specification for heavy-wall carbon and alloy steel pipe made from turned and bored forgings and is intended for high-temperature service. Heat and product analysis shall be conducted on several grades of ferritic steels, wherein the material shall conform to the required chemical composition for carbon, manganese, phosphorus, sulfur, silicon, chromium, and molybdenum. The steel pipe shall conform to the required tensile properties like tensile strength, yield strength, and elongation. Required mechanical tests for the steel pipe include transverse or longitudinal tension test, flattening test, and bend test.

This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.


1.1 This specification covers heavy-wall carbon and alloy steel pipe (Note 1) made from turned and bored forgings and is intended for high-temperature service. Pipe ordered under this specification shall be suitable for bending and other forming operations and for fusion welding. Selection will depend on design, service conditions, mechanical properties and high-temperature characteristics.

Note 1—The use of the word “pipe” throughout the several sections of this specification is used in the broad sense and intended to mean pipe headers, or leads.

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.”

1.2 Several grades of ferritic steels are covered. Their compositions are given in Table 1.

1.3 Supplementary requirements (S1 to S6) 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 SI units or inch-pound units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. 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. The inch-pound units shall apply unless the “M” designation of this specification is specified in the order.

Chemical Requirements

Grade Composition, %
Carbon 0.25 max 0.30 max 0.100.20 0.100.20
Manganese 0.270.93 0.291.06 0.300.80 0.300.61
Phosphorus, max 0.035 0.035 0.025 0.025
Sulfur, max 0.035 0.035 0.025 0.025
Silicon 0.10 min 0.10 min 0.100.50 0.100.30
Chromium 0.500.81
Molybdenum 0.440.65 0.440.65
Grade FP5 FP9 FP11 FP12
Carbon 0.15 max 0.15 max 0.050.15 0.050.15
Manganese 0.300.60 0.300.60 0.300.60 0.300.61
Phosphorus, max 0.025 0.03 0.025 0.025
Sulfur, max 0.025 0.03 0.025 0.025
Silicon 0.50 max 0.501.00 0.501.00 0.50 max
Chromium 4.006.00 8.0010.00 1.001.50 0.801.25
Molybdenum 0.450.65 0.901.10 0.440.65 0.440.65
Grade FP21 FP22 FP91 FP92
Carbon 0.050.15 0.050.15 0.080.12 0.070.13
Manganese 0.300.60 0.300.60 0.300.60 0.300.60
Phosphorus, max 0.025 0.025 0.025 0.02
Sulfur, max 0.025 0.025 0.025 0.01
Silicon 0.50 max 0.50 max 0.200.50 0.50 max
Chromium 2.653.35 1.902.60 8.009.50 8.509.50
Molybdenum 0.801.06 0.871.13 0.851.05 0.300.60

Others composition % :

Ni 0.40 max, V 0.18–0.25, Cb 0.06–0.10, N 0.03–0.07, Al 0.02 max, Ti 0.01 max, Zr 0.01 max
W 1.50–2.00, V 0.15–0.25, Cb 0.04–0.09, N 0.030–0.070, Ni 0.40 max, Al 0.02 max, Ti 0.01 max, Zr 0.01 max, B 0.001–0.006

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