ASTM-A182-F1-F5-F9-F11-F12-F22-F91-F92-Low-Alloy-Steels-Specification-for-Flange-Specification

ASTM A182 F1 F5 F9 F11 F12 F22 F91 F92 Low Alloy Steels Specification for Flange Specification

ASTM A182 / A182M – Standard Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service

Download ASTM A182 2024 pdf

ASTM A182 covers:

  • Forged or rolled alloy steel materials
  • For use in pressure systems and high-temperature services
  • Commonly applied in:
    • Petrochemical plants
    • Oil & gas processing
    • Power generation (thermal, nuclear)
    • Marine and offshore industries

ASTM A182 Flange Types Available

ASTM A182 alloy steel flanges are manufactured in compliance with:

  • ASME B16.5 (sizes up to 24″)
  • ASME B16.47 (for larger diameters)
  • Pressure Classes: 150#, 300#, 600#, 900#, 1500#, 2500#

Available types:

  • Weld Neck Flange (WN)
  • Blind Flange (BL)
  • Slip-On Flange (SO)
  • Socket Weld Flange (SW)
  • Threaded Flange (TH)
  • Lap Joint Flange (LJ)
  • Orifice Flanges

ASTM A182 Low Alloy Steel Grades

GradeUNS NumberTypical CompositionDescription / Use Case
F1K128220.5% Cr – 0.5% MoLow chromium-moly steel, basic high-temp alloy
F5K415455% Cr – 0.5% MoBetter heat and corrosion resistance
F9K909419% Cr – 1% MoHigher creep strength, used in power plants
F11K115971.25% Cr – 0.5% MoWidely used in oil, gas, and steam systems
F12K115621.0% Cr – 0.5% MoSimilar to F11 with slightly different properties
F22K215902.25% Cr – 1% MoCommon in high-pressure steam and hydrogen services
F91K909019% Cr – 1% Mo – V – NbHigh strength for supercritical steam and power applications

ASTM A182 F1 F5 F9 F11 F12 F22 F91 F92 Flange Manufacture

The low-alloy ferritic steels shall be made by the open-hearth, electric-furnace, or basic-oxygen process with the option of separate degassing and refining processes in each case.

Low Alloy steel heating treatment requirment

GradeHeat Treat TypeAustenitizing/Solution Heat Treatment Temperature, Minimum or Range, °F [°C]Cooling MediaQuenching Cool Below °F [°C]Tempering Temperature, Minimum or Range, °F [°C]
Low Alloy Steels     
F1anneal1650 [900]furnace cool
F5, F5anormalize and temper1650 [900]air cool1150 [620]
 anneal1750 [955]furnace cool
 normalize and temper1750 [955]air cool1250 [675]
F9anneal1750 [955]furnace cool
 normalize and temper1750 [955]air cool1250 [675]
F 91 Types 1 and 2normalize and temper or quench and temper1900–1975 [1040–1080]air cool, accelerated air cool, or liquid1350–1470 [730–800]
F92normalize and temper1900–1975 [1040–1080]air cool1350–1470 [730–800]
F 11, Class 1, 2, 3anneal1650 [900]furnace cool
 normalize and temper1650 [900]air cool1150 [620]
F 12, Class 1, 2anneal1650 [900]furnace cool
 normalize and temper1650 [900]air cool1150 [620]
 normalize and temper1750 [955]air cool1250 [675]
F 22, Class 1, 3anneal1650 [900]furnace cool

ASTM A182 Low Alloy steel Chemical Composition

Chemical heat analysis shall be performed and consistent with the chemical composition requirements of Table 1.

Grades that add lead, selenium or other elements to make the material easier machined, it should not be used.

Grade/Identification SymbolUNS DesignationComposition, %
CarbonManganesePhosphorusSulfurSiliconNickelChromiumMolybdenumNiobiumTitaniumOther Elements
Low Alloy Steels
F1K128220.280.60–0.900.0450.0450.15–0.350.44–0.65
F 2K121220.05–0.210.30–0.600.020.030.10–0.600.50–0.810.44–0.65
F 5K415450.150.30–0.600.020.030.50.54.0–6.00.44–0.65
F 5aK425440.250.60.040.030.50–1.000.54.0–6.00.44–0.65
F 9K909410.150.30–0.600.030.030.50–1.008.0–10.00.90–1.10
F 10S331000.10–0.200.50–0.800.040.031.00–1.4019.0–22.07.0–9.00.06–0.10N 0.03–0.07
F 91 Type 1K909010.08–0.120.30–0.600.020.010.10–0.500.48.0–9.50.85–1.050.06–0.10V 0.18–0.25
Ti 0.02
Al 0.025
Cu 0.01
F 91 Type 2K909010.08–0.120.30–0.500.0200.050.20–0.400.208.0–9.50.85–1.050.06–0.100.01N 0.03–0.07
V 0.18–0.25
Zr 0.01
Al 0.020
Cu 0.10
W 0.05
Sn 0.01
As 0.01
Sb 0.003<sup>E</sup>
N/A ratio, min 1.0
F 11K115970.05–0.150.30–0.600.030.030.50–1.001.00–1.500.44–0.65
Class 1
F 11K115720.10–0.200.30–0.800.040.040.50–1.001.00–1.500.44–0.65
Class 2
F 11K115720.10–0.200.30–0.800.040.040.50–1.001.00–1.500.44–0.65
Class 3
F 12K115620.05–0.150.30–0.600.0450.0450.50 max0.80–1.250.44–0.65
Class 1
F 12K115640.10–0.200.30–0.800.040.040.10–0.600.80–1.250.44–0.65
Class 2
F 21K315450.05–0.150.30–0.600.040.040.50 max2.7–3.30.80–0.960.015–0.035V 0.20–0.30
F 3VK318300.05–0.180.30–0.600.020.020.12.8–3.20.90–1.10V 0.20–0.30
F 3VCbK313900.10–0.150.30–0.600.020.010.10.252.7–3.30.90–1.100.015–0.0700.0150.001–0.003
V 0.20–0.30
Cu 0.25
Ca 0.0005–0.0150
F 22K215900.05–0.150.30–0.600.040.040.52.00–2.500.87–1.13
Class 1
F 22K215900.05–0.150.30–0.600.040.040.52.00–2.500.87–1.13
Class 3

Tensile and Hardness Requirements of A182 low alloy steel grade

Grade SymbolTensile Strength, min, ksi [MPa]Yield Strength, min, ksi [MPa]<sup>B</sup>Elongation in 2 in. [50 mm] or 4D, min, %Reduction of Area, min, %Brinell Hardness Number, HBW, unless otherwise indicated
Low Alloy Steels
F170 [485]40 [275]2030143–192
F270 [485]40 [275]2030143–192
F570 [485]40 [275]2035143–217
F5a90 [620]65 [450]2250187–248
F985 [585]55 [380]2040179–217
F 91 Types 1 and 290 [620]60 [415]2040190–248
F9290 [620]64 [440]2045269 max
F 11 Class 160 [415]30 [205]2045121–174
F 11 Class 270 [485]40 [275]2030143–207
F 11 Class 375 [515]45 [310]2030156–207
F 12 Class 160 [415]32 [220]2045121–174
F 12 Class 270 [485]40 [275]2030143–207
F 22 Class 160 [415]30 [205]2035170 max

ASTM A182 alloy steel F1 F5 F9 F11 F12 F22 F91 F92 Heat treatment

After hot working, forgings shall be cooled to a temperature below 1000 °F [538 °C] prior to heat treating in accordance with the requirements of Table 1.

The low alloy steels and ferritic and martensitic stainless steels shall be heat treated in accordance with the requirements of 7.1 and Table 1. When more than one heat treatment option is listed for a Grade in Table 1, any one of the heat treatments listed shall be performed. The selection of the heat treatment shall be at the manufacturer’s option, unless otherwise stated in the purchase order.

Liquid Quenching

Except as permitted in 7.2.2, for F 1, F 2, and F 3, and when agreed to by the purchaser, liquid quenching followed by tempering shall be permitted provided the temperatures in Table 1 for each grade are used.

  • 7.2.1.1 Marking—Parts that are liquid quenched and tempered shall be marked “QT.”

Alternatively, Grade F 1, F 2, and F 12, Classes 1 and 2 may be given a heat treatment of 1200 °F [650 °C] minimum after final hot or cold forming.

Nondestructive Test Requirements of ASTM A182

Hollow forgings of Grades F 91 Types 1 and 2, F 92, F 115, F 122, and F 911, with NPS 4 [DIN 100] and larger, whose finished internal surfaces are not accessible to magnetic particle or liquid penetrant examination, shall be examined by an ultrasonic test in accordance with Practice A388/A388M after all forging, mechanical processing, and heat treatment operations have been completed.


Hollow forgings of Grades F 91 Types 1 and 2, F 92, F 115, F 122, and F 911, with NPS 4 [DIN 100] and larger, whose finished internal surfaces are accessible to magnetic particle or liquid penetrant examination, shall be examined on their internal surfaces by either a magnetic particle test in accordance with Practice A275/A275M or by a liquid penetrant examination in accordance with Test Method E165/E165M, as applicable, after all heat treatment, machining, and other mechanical processing operations are completed.

A182 Alloy steel flanges Marking Requirements

Each flange is marked with:

  • ASTM A182
  • Grade (e.g., F22, F11)
  • Heat number
  • Pressure rating (e.g., 600#)
  • Manufacturer’s logo
  • Size and schedule