ASME SA335 P91 Alloy steel pipe
ASTM A335 P91 Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service
This specification covers seamless ferritic alloy-steel pipe for high-temperature service. The pipe shall be suitable for bending, flanging (vanstoning), and similar forming operations, and for fusion welding. Grade P2 and P12 steel pipes shall be made by coarse-grain melting practice. The steel material shall conform to chemical composition, tensile property, and hardness requirements. Each length of pipe shall be subjected to the hydrostatic test. Also, each pipe shall be examined by a non-destructive examination method in accordance to the required practices. The range of pipe sizes that may be examined by each method shall be subjected to the limitations in the scope of the respective practices. The different mechanical test requirements for pipes, namely, transverse or longitudinal tension test, flattening test, and hardness or bend test are presented.
1. Scope
1.1 This specification covers nominal wall and minimum wall seamless ferritic alloy-steel pipe intended for high-temperature 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”.
ASTM A335 P91 Chemical Compositions(%)
| Compositions | Data |
| UNS Designa-tion | K91560 |
| Carbon(max.) | 0.08-0.12 |
| Manganese | 0.30-0.60 |
| Phosphorus(max.) | 0.025 |
| Silicon(max.) | 0.50 |
| Chromium | 4.00-6.00 |
| Molybdenum | 0.45-0.65 |
| Other Elements | … |
Mechanical properties for ASTM A335 P91
| Properties | Data |
| Tensile strength, min, (MPa) | 415 Mpa |
| Yield strength, min, (MPa) | 205 Mpa |
| Elongation, min, (%), L/T | 30/20 |
