Flange materials acc. to ASTM

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.

Stainless Steel Flanges

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.

Chemical requirements composition, %

Chemical elements	Grade F304 (A)	Grade F304L (A)	Grade F316L (A-B)
Carbon, max	0.08	0.035	0.035
Manganese, max	2.00	2.00	2.00
Phosphorus, max	0.045	0.045	0.045
Sulfur, max	0.03	0.03	0.03
Silicon, max	1.00	1.00	1.00
Nickel	8-11	8-13	10-15
Chrome	18 – 20	18 – 20	16 – 18
Molybdenum	-	-	2.00-3.00

(A) Carbon 0.040% max. is necessary where many drawing passes are required, as with outside
diameter <0.5 inch (12.7 mm), or nominal wall thickness <0.049 inch (1.2 mm).
(B) On pierced tube, Nickel may be 11 – 16.00%.

ASTM Grades

Material	Fittings	Flanges	Valves	Bolts & Nuts
Carbon Steel	A234 Gr WPA	A105	A216 Gr WCB	A193 Gr B7 A194 Gr 2H
	A234 Gr WPB	A105	A216 Gr WCB
	A234 Gr WPC	A105	A216 Gr WCB

Carbon Steel Alloy High-Temp	A234 Gr WP1	A182 Gr F1	A217 Gr WC1	A193 Gr B7 A194 Gr 2H
	A234 Gr WP11	A182 Gr F11	A217 Gr WC6
	A234 Gr WP12	A182 Gr F12	A217 Gr WC6
	A234 Gr WP22	A182 Gr F22	A217 Gr WC9
	A234 Gr WP5	A182 Gr F5	A217 Gr C5
	A234 Gr WP9	A182 Gr F9	A217 Gr C12

Carbon Steel Alloy Low-Temp	A420 Gr WPL6	A350 Gr LF2	A352 Gr LCB	A320 Gr L7 A194 Gr 7
Carbon Steel Alloy Low-Temp	A420 Gr WPL3	A350 Gr LF3	A352 Gr LC3

Austenitic Stainless Steel	A403 Gr WP304	A182 Gr F304	A182 Gr F304	A193 Gr B8 A194 Gr 8
	A403 Gr WP316	A182 Gr F316	A182 Gr F316
	A403 Gr WP321	A182 Gr F321	A182 Gr F321
	A403 Gr WP347	A182 Gr F347	A182 Gr F347

ASTM Materials

FITTINGS

ASTM A234 = This specification covers wrought carbon steel and alloy steel fittings of seamless and welded construction.
ASTM A420 = Standard specification for piping fittings of wrought carbon steel and alloy steel for low-temperature service.
ASTM A403 = Standard specification for wrought austenitic stainless steel piping fittings.

FLANGES

ASTM A105 = This specification covers standards for forged carbon steel piping components, that is, flanges, fittings, Valves, and similar parts, for use in pressure systems at ambient and higher-temperature service conditions.
ASTM A182 = This specification covers forged or rolled alloy and stainless steel pipe flanges, forged fittings, and Valves and parts for high-temperature service.
ASTM A350 = This specification covers several grades of carbon and low alloy steel forged or ring-rolled flanges, forged fittings and Valves for low-temperature service.

VALVES

ASTM A216 = This specification covers carbon steel castings for Valves, flanges, fittings, or other pressure-containing parts for high-temperature service and of quality suitable for assembly with other castings or wrought-steel parts by fusion welding.
ASTM A217 = This specification covers steel castings, martensitic stainless steel and alloys steel castings for Valves, flanges, fittings, and other pressure-containing parts intended primarily for high-temperature and corrosive service.
ASTM A352 = This specification covers steel castings for Valves, flanges, fittings, and other pressure-containing parts intended primarily for low-temperature service.
ASTM A182 = This specification covers forged or rolled alloy and stainless steel pipe flanges, forged fittings, and Valves and parts for high-temperature service.

BOLDS & NUTS

ASTM A193 = This specification covers alloy and stainless steel bolting material for pressure vessels, Valves, flanges, and fittings for high temperature or high pressure service, or other special purpose applications.
ASTM A320 = Standard Specification for Alloy-Steel and Stainless Steel Bolting Materials for Low-Temperature Service.
ASTM A194 = Standard specification for nuts in many different material types.

Read your tape measure, in inches. The distance you have found is the diameter of your flange.