Alloy steel pipe material specifications are governed primarily by standards like ASTM A335, which covers seamless ferritic alloy-steel pipe for high-temperature service. Common grades include P11, P22, and P91 (chrome-moly grades), tailored for high pressure and temperature applications in power plants and refineries. [1, 2, 3] Key Standards and Specifications • ASTM A335 / ASME SA335: Seamless ferritic alloy-steel pipe for high-temperature use. • ASTM A333: Seamless and welded steel pipe for low-temperature service. • ASTM A213: Seamless ferritic and austenitic alloy-steel boiler, superheater, and heat-exchanger tubes. • ASTM A691: Carbon and alloy steel pipe, electrically fusion-welded for high-pressure service at high temperatures. [1, 4, 5, 6, 7] Common Chrome-Moly Grades (ASTM A335) • P11: Offers good tensile strength and high-temperature endurance; contains about 1.00–1.50% chromium and 0.44–0.65% molybdenum. • P22: Widely used in power generation; contains roughly 1.90–2.60% chromium and 0.87–1.13% molybdenum. • P91: Advanced high-strength grade containing vanadium, niobium, and roughly 8.0–9.5% chromium for extreme temperature environments. [2, 8, 9, 10, 11] Mechanical and Physical Properties • Alloying Elements: Chromium (for corrosion and oxidation resistance) and Molybdenum (for high-temperature strength and hardness). • Fabrication: Suitable for bending, flanging, and fusion welding operations. [1, 2, 3] If you'd like, let me know:The operating temperature and pressureThe specific grade or standard you needI can provide more detailed chemical breakdowns or mechanical property limits.