Miscellaneous

What is serration in flange?

What is serration in flange?

The flange face has small grooves as you can see in the image. This machining is known as a serration. Flange face can be smooth or serrated type. Soft material of gaskets is set in this serration and prevent liquid or gas from passing from flange joint.

Why does my face flange serration?

A serrated finish, either concentric or spiral, is required with 30 to 55 grooves per inch and a resultant roughness between 125 and 500 micro inches. This allows for various grades of surface finish to be made available by flange manufactures for the gasket contact surface of metal flanges.

Are flat face flanges serrated?

The most common flange face surface designs are smooth and serrated. Flat face (FF) flange surfaces and raised face (RF) flange surfaces require serrations if built to industry standards.

Can you connect a flat face flange to a raised face flange?

Flat face flanges are never to be bolted to a raised face flange. ASME B31. 1 says that when connecting flat face cast iron flanges to carbon steel flanges, the raised face on the carbon steel flange must be removed, and that a full face gasket is required.

What is difference between RF and RTJ flanges?

Answer: RF means “Raised Face.” RTJ means “Ring Type Joint.” RF flanges seal with a flat gasket, formerly made of asbestos but now made of more environmentally friendly material, designed for installation between the raised faces of two mating flanges (both with raised faces).

Can you mate a raised face flange to a flat face flange?

Flat face flanges are never to be bolted to a raised face flange. 1 says that when connecting flat face cast iron flanges to carbon steel flanges, the raised face on the carbon steel flange must be removed, and that a full face gasket is required.

How big is a flat face flange surface?

6.4.5.3 Other Flange Facings. Either a serrated concentric or serrated spiral finish having a resultant surface finish from 3.2 µm to 6.3 µm (125 µin. to 250 µin.) average roughness shall be furnished.

Do you need a serration for a flat face flange surface?

If you use ASME codes & standards, there must be a serration for flange facing as clearly indicated at Para. 6.4.5 of ASME B16.5: 6.4.5 Flange Facing Finish. Flange facing finishes shall be in accordance with paras. 6.4.5.1 through 6.4.5.3, except that other finishes may be furnished by agreement between the user and the manufacturer.

How can flanges be classified based on face finish?

The ASME b16.5 code requires that the flange face (raised face and flat face) has a specific roughness to ensure that this surface be compatible with the gasket and provide a high quality seal. A serrated finish, either concentric or spiral, is required with 30 to 55 grooves per inch and a resultant roughness between 125 and 500 micro inches.

What should the roughness be on a gasket flange?

The ASME B16.5 code requires that the flange face (raised face and flat face) has a specific roughness to ensure that this surface be compatible with the gasket and provide a high quality seal. A serrated finish, either concentric or spiral, is required with 30 to 55 grooves per inch and a resultant roughness between 125 and 500 micro inches.