Flange (ASME, MSS, API AWWA spec)details including sizes over 24 inch are well covered by Tube Turns Catalog 411. Bolt dia and lenght, flange marking, flange surface finish are some of the info you'll find in the catalog.
According to tube turns (page 94 of the catalog). raised faces are furnished from stock with modified spiral serrated gasket surface finish having from 24 to 40 grooves per inch. the cutting tool employed has an approxinate raduis of 0.06 in. the finish is judege using the visual comparison and not by stylus tracer (here the accuracy is not important) The finijhshes have a 500 micro inch max. roughness for class 150 and 300 and 250 microinch for class 400 and higher.
The other surface finish available (at extra cost - this is what i mean by economics) are smooth plane produced by machining to proudcued (guess what) a smooth surface and cold water fininsh produuced by using a formed tool at high speeds resulting in mirrorlike finish (this is what you may call a rollsroyce finish).
maybe the above would be of help. the definistion of the rms can be found at the url address given by paul.
-----Original Message-----
From: Paul Bowers [mailto:pbowers@pipingdesign.com]
Sent: 05 May, 2002 8:10 AM
To: PipingDesign@yahoogroups.com
Subject: Re: [PipingDesign] Flange Facings.
Maybe Rajesh wanted RMS definitions and a long reply about the dis/advantages regarding spiral vs. circumferential grooving of the face?
Most of these questions are covered by various codes, but digging deeper never hurts. Received on Sun May 05 01:54:00 2002
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