ASTM A182 F11 Flanges | ASME B16.5 | ASME B16.47

The ASME B16.5 and ASME B16.47 flanges can be made from ASTM A182 Gr.F11 Class 2 steels by a forging process. They may be furnished in various flange types covering welding neck, slip on, and blind, etc. Both ASME B16.5 and ASME B16.47 have endorsed the use of ASTM A182 Gr. F11 Class 2 in Material Group 1.9, which has the nominal chemical composition of 1.25Cr-0.5Mo-Si. Flanges made from this steel are generally used with maximum working temperature limit of 590°C [1100°F]. It is permissible but not recommended for prolonged use above 590°C [1100°F].

Chemical Composition Requirements

Element	Composition, %
C	0.10-0.20
Mn	0.30-0.80
P	≤0.040
S	≤0.040
Si	0.50-1.00
Cr	1.00-1.50
Mo	0.44-0.65

*The UNS number of ASTM A182 Gr. F11 Cl. 2 is K11572.

Mechanical Properties

Tensile Strength min. ksi [MPa]	70 [485]
Yield Strength min. ksi [MPa]	40 [275]
Elongation in 2", min. %	20
Reduction of Area, min. %	30
Brinell Hardness HBW	143-207

*Tensile and hardness requirements.

Manufacture & Heat Treatment

The starting material of the ASTM A182 Gr. F11 Cl. 2 flange shall be low-alloy ferritic steels made by the open-hearth, electric-furnace, or basic-oxygen process with the option of separate degassing and refining processes in each case. The material shall be forged as close as practicable to the specified flange shape and size. After hot forging, the flange sahll be cooled to a temperature below 538°C [1000°F] prior to heat treating. ASME B16.5 or ASME B16.47 flanges made of ASTM A182 Gr. F11 Cl. 2 steels shall be furnished in normalizing and tempering condition only. The minimum austenitizing temperature is 900°C [1650°F]. The normalizing requires air cooling, which is followed by tempering with minimum tempering temperature of 620°C [1150°F].

Pressure-Temperature Ratings

*Pressure-Temperature ratings for ASTM A182 Gr. F11 Cl. 2 flanges of Class 75, 150 and 300; Values in “75#” column only applies to ASME B16.47 Series B Class 75 flanges; Values in columns “150#” and “300#” are applicable to both ASME B16.5 and B16.47 flanges of Class 150 and Class 300, respectively.

*Pressure-Temperature ratings for ASTM A182 Gr. F11 Cl. 2 flanges of Class 400, 600 and 900; applicable to both ASME B16.5 and B16.47 flanges.

*Pressure-Temperature ratings for ASTM A182 Gr. F11 Cl. 2 flanges of Class 1500 and 2500; applicable to ASME B16.5 flanges only.