Why does my face flange serration?

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.

What is serration on flanges?

Serration on the Flange Face 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.

What is serrated surface?

Serration is a saw-like appearance or a row of sharp or tooth-like projections. A serrated cutting edge has many small points of contact with the material being cut. For example, the teeth on a saw or other serrated blade serves a similar cutting or scraping purpose as the serration of an animal tooth.

What does RTJ flange mean?

Ring-Type Joint
The Ring Type Joint flanges are typically used in high pressure (Class 600 and higher rating) and/or high temperature services above 800°F (427°C). An RTJ flange may have a raised face with a ring groove machined into it. This raised face does not serve as any part of the sealing means.

What do serrations do?

Slicing uses a coarse micro edge or a serrated edge to cut. This is one of the most common serrated knife uses, as the serrations help the knife bite into the surface. The toothiness of the edge also allows the knife to cut into the substrate, allowing it to quickly work through fibers.

What is flange face?

The flange face is the surface area that hosts the gasket. Flanges with different faces require different gaskets and shall never be mated to prevent leakage of the joint. RF and FF flanges may have different types of “finish” (i.e. roughness on top the surface): smooth, stock and serrated.

Can you use a raised face flange with a flat 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.

How do raised face flanges work?

Raised Face and Flat Face The raised face is intended to decrease the surface area of the seal, thus concentrating the surface pressure applied when mating the flange. The result is a stronger seal. The raised face has a machined serrated finish that will bite into the gasket whenever pressure is applied.