surface roughness on tube hole?

[UserAK]

Dear Sirs,

I can not find on ASME either on TEMA a reference about the surface roughness tolerances on a tube hole of a tube-sheet.
I mean, I would except something like: tube-hole OD=19mm then surface roughness max. 5micron.
It seems very strange to me since tube-hole surface roughness is very important for a tight sealed expanded joint.
Please advise.

Regards,

A.K

 

[metengr]

Look here

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCkQFjAA&url=http://

http://www.venus-boiler.com/technic...xYH4BQ&usg=AFQjCNEu_N1gDWe64KbU6zBmuYmrEnnNLg

 

[EdStainless]

In many cases people deliberately roughen the holes with a wire brush.
roughness in good as long as it is all circumferential.


= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[muld0020]

There are more than 1 type of tubesheet (boiler tubes, condensers, heat exchangers, etc..). If you have a HEI Condenser then HEI says 500 RMS, typically TEMA heat exchangers have 125-250 RMS tubesheet hole finish. If you are looking at enhancing the tubejoint with a surface finish then you probably want to look at your push out loads. Roughness and Grooves don't always make the tightest seal it is highly dependent on the materials of the tube and tubesheet. I have seen some tubesheet-tube combinations where a smooth hole has better push-out loads compared to grooved holes. I couldn't imagine the ASME code would specify the surface finish since there are so many possibilities and it should be left to the design engineers.