ALLOY STEEL FLANGE WN RF ASME SA182 GR F11 CL2 B16.5

ALLOY STEEL FLANGE WN RF ASME SA182 GR F11 CL2 B16.5

This is a 1.25Cr-0.5Mo chrome-moly alloy steel weld neck flange, designed for high-temperature and high-pressure service.

ASTM A182 F11 Class 2 is a forged chromium-molybdenum alloy steel with 1.25% chromium and 0.5% molybdenum. The Class 2 designation refers to a specific mechanical property level: minimum yield strength of 275 MPa and tensile strength of 485 MPa, with hardness capped at 197 HBW.

Usage

This flange is specified wherever carbon steel loses strength above 425°C due to creep. Its primary applications include:

- Refinery piping: crude/vacuum distillation overhead, FCC reactor effluent, reformer charge heaters

- Power generation: boiler superheater/reheater headers, main steam branch connections

- Petrochemical: high-temperature process units and transfer lines

It is typically paired with A335 P11 pipe and A234 WP11 fittings to maintain alloy compatibility.

Advantages

- Creep strength at temperature: Molybdenum provides resistance to slow deformation under sustained stress, extending reliable service to 565°C (1050°F) continuously and up to 593°C (1100°F) under ASME B16.5 ratings.

- Oxidation and sulfidation resistance: Chromium content protects against high-temperature oxidation and sulfur attack.

- Hydrogen attack resistance: Suitable for moderate hydrogen service per API 941 Nelson curves.

- Cost-effective chrome-moly: As the lowest-chromium grade in the common chrome-moly family, F11 offers the most economical solution when higher alloys like F22 or F5 are not required.

Product Range:

WNRF Flanges Size : 1/8" NB TO 48"NB.

WNRF Flanges Class : 150#, 300#,400 #,600#,900#, 1500# & 2500 #.

Alloy Steel WNRF Flanges : ASTM A 182, GR F1, F11, F22, F5, F9, F91

Weld Neck Flanges Weld Neck Flanges (WN flanges) are a type of pipe flange designed for high-pressure and high-temperature applications. They are widely used in industries such as oil and gas, petrochemical, power generation, and chemical processing due to their strength, reliability, and ability to handle extreme conditions.