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What is a Flange?

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.

What are ASTM Grades?
For example, a carbon steel pipe can be identified with Grade A or B, a stainless-steel pipe with Grade TP304 or Grade TP321, a carbon steel fitting with Grade WPB etc.

Stainless Steel

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%.

FREQUENTLY USED ASTM GRADES
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".
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
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

ASTM International, known until 2001 as the American Society for Testing and Materials (ASTM), is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services.

FITTINGS

Pipe fittings are used to connect pipes. There are different varieties of pipe fittings made of various materials and available in various shapes and sizes.

  • 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

A flange is a method of connecting pipes, valves, pumps and other equipment to form a piping system.

  • 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

A valve is a device that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways.

  • 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
Flange bolts

Flange bolts are those type of bolts having a ridge or skirt around the bolt head. They are also know as frame bolts and are designed to provide the holding power as if a washer was installed.

  • 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.


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