Not logged inAmerican Welding Society Forum
Forum AWS Website Help Search Login
Up Topic Welding Industry / Technical Discussions / Lap Joint Flanges
- - By Shane Feder (****) Date 02-14-2007 22:49
Good morning everyone,
Can somebody please tell me what standard I need to locate for tolerances on Lap joint stub ends.
I have got an 800nb S/S Sch 20 stub end with a 300# backing flange. Prior to my arrival on site a defect was found on the stub end flange face and this was machined off. My concern is that they have taken too much off but I cannot find tolerances anywhere.
Any help would be greatly appreciated.
Regards,
Shane
Parent - By hogan (****) Date 02-14-2007 23:05
would that be ansi B16 ? it's been a while since i've looked at that
Parent - - By G.S.Crisi (****) Date 02-15-2007 18:10
800 nb means that the Nominal Bore is 800 millimeters. So, that stub end doesn't follow any American standard.
Now, Shane is from Australia, so I'd guess that the standard is a British one. I used to have the British standards for pipíng at home years ago, but I don't know if they're still there. I'll take a look this night and come back tomorrow.
Giovanni S. Crisi
Sao Paulo - Brazil
Parent - - By G.S.Crisi (****) Date 02-16-2007 19:24
Sorry, Shane, what I've got at home is not the complete British standard but just an excerpt of it published by an English piping fittings manufacturer. The publication goes up to 8 inches, which is the maximum diameter he makes.
800 millimeters is approximately 34 inches, so your stub end doesn't fall under any American standard. ANSI B36 goes up to 24 inches.
Now, looking for the British standard, I've found an old Taylor Forge catalog describing the special fittings they manufacture, including stainless steel stub ends and backing flanges. It's important to point out that those fittings, from 26 to 36 inches, doesn't follow any published standard; they're made "under Taylor Forge internal standards". Now, being Taylor Forge a well known, highly respected manufacturer, we can safely take for granted what he says.
Having said all that, I'll tell you that the maximum underthickness tolerance for a 34 inches, stainless steel stub end facing is 20 thousanths of an inch, about 0.5 millimeters.
Does this informations help you in any manner?
Giovanni S. Crisi
Parent - - By Shane Feder (****) Date 02-16-2007 20:11
Giovanni,
Greetings from "downunder".
Thank you for your assistance,I managed to find some info in B16.9.
Basically what it is telling me is the stub end (flange face) must be at least as thick as the pipe it is being welded to.
Thanks again,
Regards,
Shane
Parent - - By G.S.Crisi (****) Date 02-21-2007 22:01
Shane,
we've got one thing in common: both of us live in the southern hemisphere, where Christmas and New Year are in summer, an incredible thing for those who live in the upper part of the planet.
Giovanni 
Parent - By Shane Feder (****) Date 02-21-2007 23:26
Hello Giovanni,
I am currently working in New Caledonia on the Goro Nickel Project which is the largest Laterite Nickel Mine in the world. The owners (Inco) have just been bought out by CVRD which as you are aware is rather a large company from your neck of the woods. Quite an exciting project as we have piping and tanks being made from carbon, s/s,chromolly,duplex, super-duplex and titanium.
Beautiful place to work and I can see why they call French the language of romance, the women are superb and I could listen to them talk all day long.
Au revoir mon ami,
Shane
Parent - - By JM_VRCIC (*) Date 02-03-2010 17:12
Shane, good afternoon, sorry to bother and get from the deads this thread but I have a question about lap joint stub ends. In my company, we're welding this kind of fittings and we assume they are according to B16.9, are we wrong? Our inspection says that this material is not covered by this ANSI/ASME Std so we are using fittings not covered by their pipe class. Are they wrong? Are lap joint stub ends covered by the std? As I read the ASME B16.9 in para 1.3 I guess they are covered, but I might be wrong...

Hope you or anyone can give some info.

Best regards,
Parent - - By Shane Feder (****) Date 02-03-2010 23:55
JM_VRCIC,
What does your mill certificate / material certificate state ?
This should tell you what standard they are manufactured to.
Regards,
Shane
Parent - - By Steve.E (**) Date 02-04-2010 09:58
Hi Shane our company has done a few Titanium clad vessels for that project (W.E. Smith Eng. ) let me know if you see any .
Parent - - By Shane Feder (****) Date 02-05-2010 00:52
Hi Steve,
We had nine huge titanium clad Fleater Vessels that were fabricated in Australia but were rejected and are now sitting in a paddock (in WA I think).
They refabricated them in Korea (about 2 years work) and the job went completely "pear shaped"
Cheers,
Shane
Parent - - By ssbn727 (*****) Date 02-05-2010 02:52
They should have gone to the Titanium Fabrication Corporation... Here's their homepage:

http://www.tifab.com/

Here's an interesting article regarding clad vessels as well as methods of cladding, etc.

http://www.tifab.com/pdf/Clad%20Construction%20-%20TiFab.pdf

I used to do a bunch of work for these folks both out in the field as well as on the shop floor... So I know these folks are second to none!!! ;) A real class outfit IMHO!!! :) :) :)

Respectfully,
Henry
Parent - - By Steve.E (**) Date 02-05-2010 10:10
Just a little one we did for Ravensthorp
Attachment: Autoclave1.jpg (0B)
Parent - - By ssbn727 (*****) Date 02-05-2010 16:24
Hi Steve!

May I ask what was the wall thickness of the autoclave and was it cladded material or just Ti throughout??? Also, what grade of material was used for the shell?

Respectfully,
Henry
Parent - By Steve.E (**) Date 02-06-2010 07:07
Hi Henry... Didn't mean to hijack your thread Shaun.. sorry mate, Henry this was an internal clad unit 100mm carbon wall A516-70 from memory with 10mm grade 17 Ti lining, 400 tone all up. Something I'm sure you will be interested in Henry is a little project we have in the pipeline , Its a navsea rescue pod for US Navy hope those submariners never have to use it . Info is a bit sketchy at the moment but will let you know more at a later date.
Parent - - By Steve.E (**) Date 02-05-2010 10:22
Hay Shane .. Goro must have money to burn we fabricated 16 clad vessels for them about 6 years back , we were paid in full 2 million a pop and then they decided to change the process system which rendered the units obsolete. They sat in our compound for a couple of years , they even paid for storage. those units have now been sold for scrap.
Parent - - By Jim Hughes (***) Date 02-09-2010 00:22 Edited 02-09-2010 23:47
Shane its ASME B16.5. Gives you all the dimensional info your looking for in Annex F.

Jim
Parent - By Shane Feder (****) Date 02-09-2010 05:34
Cheers Jim,
Thank you for the response.
Regards,
Shane
Up Topic Welding Industry / Technical Discussions / Lap Joint Flanges

Powered by mwForum 2.29.2 © 1999-2013 Markus Wichitill