What is serrated face in flange?
What is serrated face in flange?
Serrated flange surfaces consist of concentric circular grooves, or a continuous spiral groove (also known as ‘phonographic’) machined onto the flange sealing surface. Serrated flange surfaces use non-metallic (soft) and semi-metallic gaskets.
Which gasket is preferred for serrated finish flange finds its use?
This machining is known as a serration. Flange face can be smooth or serrated type. Which type of face to use is depends on the type of the gasket and service of the fluid. Smooth finish is used with metallic gasket whereas serrated finish is used with non-metallic gasket.
When would you use a serrated flange?
Serrated tooth nuts work well for oversized or irregularly shaped holes, since the flange covers any discrepancies and serrations cover the entire bearing surface.
Do you need washers with flange nuts?
On a serrated flange nut, the serrations are angled such that they keep the nut from rotating in the direction that would loosen the nut. Because of the serrations they cannot be used with a washer or on surfaces that must not be scratched. Flange nuts (and bolts) are widely used in automobiles and electronic products.
Are flange nuts the same as lock nuts?
“Flange nuts” are a type of fastener with a wide bottom circular flange. While the flange locknuts are prevailing torque type locknuts and serrated flange nuts are free spinning. But, they feature a serrated bearing surface to grip the mating surface.
How does a RTJ flange work?
RING JOINT FLANGE (RTJ) A ring joint flange features a circular groove to accommodate a ring joint gasket (oval, or rectangular). As the two ring joint flanges are bolted together and then tightened, the applied bolting force deforms the gaskets inside the flange groove creating a very tight metal-to-metal seal.
What does 125 aarh mean on a finish?
Serrated finishing 125 – 250 micro inches (Ra = 3.2 – 6.3 micro meter = 125 – 250 AARH). As said above,AARH stands for Arithmetic Average Roughness Height. It is used to measure the roughness (rather smoothness) of surfaces. 125 AARH means 125 micro inches.there is a Surface roughness Conversion chart
What type of finish should I use on the flange faces?
We recommend that metal flange faces be machined with a concentric-serrated finish of 125-500 AARH, with 250 AARH being the optimum for non-metallic gaskets. Phonographic serrations can also be used with our materials.
What is the aarh value of spiral serrated finish?
The resulting “Ra” value (AARH) for the surface ranges from 125µinch to 500 µinch (125 µm to 12.5 µm). Spiral serrated finish is a phonographic spiral groove type that differs from the stock finish as the groove is crafted by a 90 degrees tool (instead of a round nosed one) that creates a “V” geometry with a 45-degree serration angle.
What is the typical finish of a hydrogen flange?
The finish for flanges in hydrogen service is very smooth, typically between Ra 2 and 3.2 micrometers (79 – 125 microinch). Cold Water Finish. The flange face appears as mirror like. This flange finish is usually expected to be used with metal to metal contact, i.e. without a gasket.
