China Suppliers Factory for ASME B16.5 Class 150 Carbon Steel Lap Joint Flanges (LJF) - Quality Forged Steel Flanges
ASTM A105 / A105N | ASTM A350 LF2 / LF3 | ASTM A694 F42 / 46 / 56 / 60 / 65
ASTM A182 F304 / 304L / 304H, 316 / 316L, 310S, 317, 347, 904L | ASTM A182 F51, F53, F44
ASTM A182 F11 / 12 / 5 / 9 / 91 / 92
RF | FF | FTJ
ASTM A105 is the standard specification for carbon steel forgings for piping applications. The suffix "N" in A105N indicates that the material has been normalized — a heat treatment process that improves mechanical properties and relieves internal stresses, making it more suitable for high-pressure or critical service conditions.
ASTM A350 LF2 and LF3 are low-temperature carbon steel grades designed for cryogenic or sub-zero service environments. If your application involves temperatures below -20°F (-29°C), these grades are preferred over A105 due to their enhanced notch toughness and impact resistance at low temperatures.
ASTM A182 F316L contains molybdenum (typically 2–3%), which significantly improves corrosion resistance, especially against chlorides and acidic environments. Compared to 304L, 316L is better suited for marine, chemical processing, and pharmaceutical applications where exposure to aggressive media is a concern.
ASTM A182 F51 is a duplex stainless steel (UNS S31803 / S32205) known for its high strength and excellent resistance to stress corrosion cracking and pitting. It is commonly used in offshore oil and gas, desalination plants, and chemical processing industries where both strength and corrosion resistance are critical.
RF (Raised Face) is the most common sealing face, concentrating bolt load on a smaller gasket area for a reliable seal. FF (Flat Face) is used when connecting to cast iron or brittle flanges to avoid bending stress. FTJ (Female and Tongue & Groove) provides a self-aligning, high-integrity seal ideal for critical or high-pressure applications where leakage prevention is paramount.
For high-temperature service, ASTM A182 F91 and F92 are widely recommended. These chrome-molybdenum-vanadium alloy steels offer superior creep resistance and long-term strength at elevated temperatures (up to 600°C / 1112°F), making them ideal for power generation, petrochemical, and high-temperature steam piping systems.