RF Smooth Finish

[tigeralum]

I referred to an old thread here on this subject.

http://www.eng-tips.com/viewthread.cfm?qid=142842

I am still not clear on this.

I read somewhere that RF smooth finish is perfectly flat and smooth and does not have any serrations.

http://www.wermac.org/flanges/flanges_general_part6.html

The link different RF types like concentric serrations, spiral serrations and smooth finish with no serrations.

Is it correct?

what is the acronym for this smooth finish?

 

[JLSeagull]

Flat face and smooth finish are not the same. A raised face ASME B16.5 flange finish details changed with the 1996 edition fo the standard. See section 6.4.5 for flange finish details.

The required standard serrated concentric or serrated spiral finish ranges from 3.2 micro meter 6.3 micro meter (125 micro inch to 250 micro inch) average roughness. I used to see the 125 to 250 micro inch as smooth finish. This is now the required standard finish. The flanges are also to be judged using the Ra standards described in ASMB B46.1. Perhaps anything better than 3.2 micro meter roughness is regarded as smooth finish.

 

[tigeralum]

Thanks for the reply JLSeagull

what do you call it, that has a raised face but no serrations and is perfectly smooth?

 

[racookpe1978]

A "Likely to get scratched and leak like a sieve" surface? 8<)