ASTM A369/A369M-24
Standard Specification for Carbon and Ferritic Alloy Steel Forged and Bored Pipe for High-Temperature Service

Standard No.

ASTM A369/A369M-24

Release Date

2024

Published By

American Society for Testing and Materials (ASTM)  US  /  ASTM

Latest

ASTM A369/A369M-24

Introduction

Standard Overview and Technical Evolution

ASTM A369/A369M-24 specifies the technical requirements for heavy-walled carbon and alloy steel forged, bored tubing intended for high-temperature service. Since its initial publication in 1953, the standard has undergone numerous revisions. The 2024 edition primarily adjusts the cooling rate requirements (Supplementary Requirement S7) for FP91 Type 2 material and the wording of heat treatment provisions. 1.5% Cr 0.1-1.5%, Mo 0.6-1.7% 550-650℃ FPA/FPB C≤0.30%, Mn 0.27-1.06% ≤450℃ Cr-Mo alloy FP11/FP22 Cr 1-9.5%, Mo 0.44-1.13% 550-650℃ Advanced high strength steel FP91/FP92 Cr 8-9.5%, W 1.5-2%, V/Nb microalloy ≤650℃

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Key performance requirements

Mechanical properties

According to Table 2, different grades of materials must meet the following minimum requirements:

• FP91/FP92: tensile strength ≥85ksi(585MPa), yield strength ≥60ksi(415MPa)
• FP115: elongation ≥30% in longitudinal direction, ≥20% in transverse direction
• All grades must pass the 180° bend test (when the wall thickness/diameter ratio is ≤7)

Special process control

For FP91 Type 2 and FP115 materials, the standard specifically stipulates:

1. Normalizing temperature 1900-1975°F(1040-1080°C)
2. Tempering temperature 1350-1470°F(730-800°C)
3. Cooling rate ≥9°F/min(5°C/min) in the range of 1650-900°F

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Implementation recommendations

Welding repair specifications

Note that for welding repairs of FP91/FP92 materials:

Processing methods	Applicable welding material standards	Ni+Mn content limit
SMAW	AWS A5.5 E90XX-B9	≤1.0%
SAW	AWS A5.23 EB9+neutral flux

After repair, post weld heat treatment of 730-800°C must be carried out, and FP115 needs to be controlled in the range of 730-780°C.

Purchasing Technical Points

The following parameters should be specified when ordering:

• Material grade (specified in Table 1)
• Dimensions (inside diameter and minimum wall thickness)
• Medium thickness performance verification requirements for FP91/FP92
• Whether to adopt supplementary requirements S1-S7
• Special marking requirements (such as S6 instead of heat treatment)