ASTM A182 F11, F22, F304, F316 (Alloy and Stainless Flange) Specification

ASTM A182/A182M specifies forged or rolled alloy and stainless steel piping components for pressure systems, including pipe flanges, forged fittings, valves and similar parts. The specification controls material grade, chemical composition, mechanical properties, heat treatment and applicable testing requirements rather than defining a complete flange solely by size or pressure Class.

For flanges, commonly specified ASTM A182 grades include chromium-molybdenum alloy steels such as F11 and F22 and austenitic stainless steels such as F304/F304L and F316/F316L. Grade selection changes the material chemistry, heat-treatment route and resulting service characteristics, while flange dimensions, facing, bolt pattern and pressure-temperature Class are established by the applicable dimensional standard, such as ASME B16.5 or ASME B16.47.

Standard Scope

ASTM A182/A182M covers forged low-alloy and stainless steel piping components manufactured to purchaser-specified dimensions or to referenced dimensional standards. The material families include low-alloy steels together with ferritic, martensitic, austenitic and ferritic-austenitic stainless steels, so the required grade needs to be selected according to the design temperature, pressure system and service environment.

Products supplied to ASTM A182/A182M are limited to a maximum individual weight of 10,000 lb [4540 kg]. Products machined directly from bar or hollow bar are subject to separate material-specification provisions except where specifically addressed by ASTM A182/A182M.

Supplementary inspection or testing requirements apply only when they are individually specified in the purchase order. ASTM A182/A182M is available in inch-pound and SI forms; unless the “M” designation is specified in the order, material is furnished to the inch-pound requirements of the specification.

Common Grades

Alloy grade: ASTM A182 F5, F9, F91, F92, F11, F12, F21, F22
Stainless steel grade: ASTM A182 F304, F304L, F316, F316L

Alloy Flange: ASTM A182 F11, F22

ASTM A182 Grades F11 and F22 are chromium-molybdenum low-alloy steel grades used for forged piping components where elevated-temperature strength and the specified heat-treatment condition are important to material selection.

Stainless Steel Flange: ASTM A182 F316

ASTM A182 F316 and F316L are austenitic stainless steel grades used for forged flanges where the material specification calls for a molybdenum-bearing stainless grade. The material may be applied to flange forms such as weld neck, slip-on, blind and socket-weld flanges when permitted by the applicable dimensional and project specification.

Flange size and pressure Class are determined by the applicable dimensional standard rather than ASTM A182/A182M alone. ASME B16.5 covers flanges through NPS 24, with Class 2500 limited to NPS 12, while ASME B16.47 covers large-diameter steel flanges from NPS 26 through NPS 60 in Classes 75 through 900.

Units

ASTM A182/A182M provides both inch-pound and SI requirements. Unless the purchase order specifies the ASTM A182M designation, material is furnished using the inch-pound requirements. Values from the two unit systems should not be combined when determining compliance.

Manufacture Types

For Low Alloy Ferritic Steels

Low alloy ferritic steels should be smelted in one of the following methods:
a. Open hearth furnaces
b. Electric furnaces
c. Basis -oxygen process (with the option of separate degassing and refining processes).

For Stainless Steel

Stainless steel should be smelted in one of the following ways:
a. Electric furnace (with separate deoxidation and refining (optional))
b. Vacuum furnace
c. One of the above, followed by vacuum or electroslag self-consumption remelting.
The discard should be removed sufficiently, so as to ensure the elimination of harmful shrinkage and excessive segregation.

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.

It is not permissible to add any element that exceeds the corresponding material grade listed in Table 2 for the raw materials produced in accordance with a certain standard.
Except for nitrogen in stainless steel, the ordered grade shall not contain unspecified elements to the extent that the content meets the requirements of another grade, which have the specified element with the minimum required content.

Table 1:

C: The present grade F 5a (0.25 max carbon) previous to 1995 eas assigned the identification symbol F 5. Identification symbol F 5 in 1955 was assigned to the 0.15 max carbon grade to be consistent with ASTM soecification for other products such as pipe, tubing, bolting, welding fittings, and the like.

D: Applies to both heat and product analysises.

I: Grade F 321 shall have a titanium content of not less than five times the carbon content and not more than 0.70%.

Mechanical Properties

For the grade ordered as listed in Table 2, the mechanical properties of the material shall comply with the requirements.

Table 2:

C: For sections over 5 in. [130 mm] in thickness, the minimum tensile strength shall be 70 ksi [485 MPa].

D: For sections over 5 in. [130 mm] in thickness, the minimum tensile strength shall be 65 ksi [450 MPa].

Tension Test

For low alloy steel, ferritic and martensitic stainless steel, one tension test shall be performed for each heat in each heat treatment charge.

When the heat treating cycle are the same and the furnace is controlled within ±25°F[±14℃]. And it is equipped with a recording pyrometer, so as to obtain a complete heat treatment record. However, only one tensile test is performed for each heat of each forging type and section size, rather than the per heating in each heat treatment charge.

Retreatment

If the results of the mechanical properties test do not meet the specified requirements,  and the forgings may be performed heat treatment again. Meanwhile the mechanical properties test should comply with requirement.

Nondestructive Test Requirements

For hollow forgings of grades F91, F92, F122 and F911, greater than or equal to NPS 4 (DIN 100). The inner surface of which cannot be inspected by magnetic particle or liquid penetration, the ultrasonic inspection shall be carried out in accordance with A388 / A388M.

If the inner surface is accessible, it shall be examined by the magnetic particle in accordance with regulation A275/A275M, or by the penetration test according to test method E165.

Main point of Manufacture

The material should be forged as close to the actual specified shape and size as possible.
Elbows, U-bends, tees, connecting tees and any type of flange should not be processed directly from bars.

Cylindrical shaped parts can be machined using forged or rolled solution annealed austenitic stainless steel without the need for additional thermal processing.

Cylindrical shaped low-alloy, martensite, ferrite and ferrite-austenitic stainless steel parts that less than or equal to NPS-4 [DN 100], may be machined using forged or rolled bars without additional hot processing.

Heat Treatment

Heat Treatment for Forgings

After hot working, and the forgings shall be cooled to a temperature less than 1000 °F [538 ℃] before heat treatment as specified in Heat treatment Table 3.

Table 3:

A: Minimum unless temperature range is listed
B: Not applicable
E: Forged or rolled bar meeting the requirements of 7.5 shall be liquid quenched or rapid-cooled by other means in accordance with Specification A484/ A484M

Low-alloy steels, ferritic and martensitic stainless steels

Low-alloy steels, ferritic and martensitic stainless steels shall be heat-treated in accordance with table 3. When more than one heat treatment is listed (optional) for a grade in table 3, any one of these is acceptable. The choice of heat treatment should be determined by the manufacturer, unless otherwise specified in the order.

Liquid Quenching

Except for F1, F2 and F3 in 3.2.2, if the temperature of each grade in Table 3 is used with the consent of purchaser. So the liquid should be allowed to quench, then tempered.
Marking
Parts that are liquid quenched and tempered, and shall be marked with the letter ''QT''.

Grades F1, F2 and F12

In addition, grades F1, F2 and F12, Class 1 and 2 can be done a heat treatment with a minimum temperature of 1200°F, (650℃) after final cold or hot forming.

Austenitic and ferritic-austenitic stainless steels

Austenitic and ferritic-austenitic stainless steels shall be heat treated and liquid quenched in accordance with Table 3.

Time for Heat Treatment

Heat treatment of forgings can be carried out before machining.

Forged or Rolled Bar

Forged or rolled austenitic stainless steel rods for cylindrical shaped parts as specified in mechanical properties requirement. And the parts machined from bar without heat treatment after processing. It shall comply with annealing and quenching or rapid cooling requirements of A484 / A484M or this specification, and also allows for subsequent light cold drawing and straightening.

Surface Finish, Appearance and Corrosion Protection

Forgings and finished parts shall be free of scale and machined burrs that may interfere with installation, and other harmful defects as referred to in this standard. They shall have good processing quality, and the roughness of machined surfaces (except for special requirements) shall not exceed 250AA (arithmetic mean).

Welding Repair Requirements

ASTM A182 Flange Grade Selection and RFQ Information

ASTM A182/A182M identifies the material grade and its manufacturing, chemical, mechanical and heat-treatment requirements, but it does not by itself completely define a finished flange. Grade selection and flange configuration need to be considered separately in the purchase specification.

For alloy-steel grades such as F11 and F22, material selection needs to account for the specified temperature range and heat-treatment condition. For stainless grades such as F304/F304L and F316/F316L, corrosion environment, temperature and project material requirements remain important selection inputs.

The flange pressure-temperature rating should be checked against the applicable ASME dimensional standard and material group rather than inferred from the ASTM A182 grade alone. Large-diameter flanges also need the correct standard boundary: ASME B16.5 covers flanges through NPS 24, while ASME B16.47 covers NPS 26 through NPS 60.

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