Flange Materials Specification

Dimensions from carbon steel and stainless steel flanges are defined in the ASME B16.5 standard. The material qualities for these flanges are defined in the ASTM standards.
These ASTM standards, define the specific manufacturing process of the material and determine the exact chemical composition of pipes, fittings and flanges, through percentages of the permitted quantities of carbon, magnesium, nickel, etc., and are indicated by "Grade".
For example, a carbon steel flange can be identified with Grade F9 or F11, a stainless-steel flange with Grade F316 or Grade F321 etc..
Below you will find as an example a table with chemical requirements for fittings ASTM A403 Grade WP304, WP304L, WP316L and a table with frequent Grades, arranged on pipe and pipe-components, which belong together as a group. As you may be have noted, in the table below, ASTM A105 has no Grade. Sometimes ASTM A105N is described;
"N" stands not for Grade, but for normalized. Normalizing is a type of heat treatment, applicable to ferrous metals only. The purpose of normalizing is to remove the internal stresses induced by heat treating, casting, forming etc.
Carbon Steel Flange
ASTM A105, ASTM A350 LF1, LF2 CL1/CL2, LF3 CL1/CL2
ASTM A694 F42, F46, F48, F50, F52, F56, F60, F65, F70
Stainless Steel Flange
ASTM A182 F304/304L, F316/316L, F316H, F310, F321, F44 (UNS S31254)
Alloy Steel Flange
ASTM A182 F1, F5a, F9, F11, F12, F22, F91
Chemical Requirements (Composition, %, max)
Material SymbolCMnPSSiNiCrMoCuNVCo
ASTM A1050.350.60-1.050.0350.0400.10-0.350.400.300.120.40_0.08_
ASTM A350 LF20.300.60-1.350.0350.0400.15-0.300.400.300.120.40_0.080.02
ASTM A182 F3040.082.000.0450.0301.008.0-11.018.0-20.0_____
ASTM A182 F304L0.032.000.0450.0301.008.0-13.018.0-20.0_____
ASTM A182 F3160.082.000.0450.0301.0010.0-14.016.0-18.02.00-3.00____
ASTM A182 F316L0.032.000.0450.0301.0010.0-15.016.0-18.02.00-3.00____
ASTM A182 F3210.082.000.0450.0301.009.0-12.017.0-19.0_____
EN 10025 S235JR0.201.400.0450.045_____0.009__
20Mn0.17-0.230.70-1.000.0350.0350.17-0.370.300.25 0.25   
200.17-0.230.60-1.000.0300.0200.17-0.370.250.25 0.25   
16Mn0.13-0.191.20-1.600.0300.0200.20-0.600.300.30 0.25   
Mechanical Requirements
Material SymbolTensile Strength, min, MPaYield point, min, MpaElongation, min, %Reduction of area, min, %Hardness, max, HBMin. Impact
Average, J
Test Temperature, °C
ASTM A1054852502230187  
ASTM A350 LF2485-6552502230 20-46
ASTM A182 F3045152053050   
ASTM A182 F304L4851703050   
ASTM A182 F3165152053050   
ASTM A182 F316L4851703050   
ASTM A182 F3215152053050   
20Mn4502752450197  
204102452555156  

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