Welding different schedules of pipe

By jarsanb (***)

Date 09-18-2007 19:50

Yes. Not sure exactly where in the ASME it is but others will likely have the reference #. Our company is allowed to copy this info and add it into our Inspection Manuals. In short, you are allowed 1/16 misalignment on same wt joints. On joints where there are unequal wt's, 3/32" is allowed if it is evenly spaced - and root edges completely fused. For wt's greater than 3/32, back-beveling 14 deg. to 30 deg is required or backwelding. Seeing the chart will obviously be more useful.

By js55

Date 09-18-2007 20:01

You need to be careful when asking questions such as "any code". And if I may disagree, there is no restriction under AWS or ASME that I know of for differential thicknesses as long as the transition envelope is within that required by the governing code. Especially when talking about ASME where forgings meant to match up to piping may have a thickness 3, 4 or considerably more times that of the piping it matches to in ID. Especially power piping where they will block forge fittings and then bore the ID to specification.
I believe there is a misunderstanding here between thickness limitation and fit up high low, or ID mismatch, in which case certain transition requirements are imposed as well.

By jarsanb (***)

Date 09-18-2007 20:38

Correct. I was thinking strictly high low & unequal wall thicknesses of butt joints. My apologies...

By ndshinde Date 09-18-2007 23:22

Sorry for giving incomplete information. I wanted to know about guidelines to be followed while butt welding pipe ends of same size but different thicknesses. In such case what is the allowed difference in the thicknesses? Even ASME B16.25 also doesn't say anything about it. But JARSANB, you gave me a better guideline about it. Thanks a lot for that.
It will be helpfull if a chart or something of that sort, which lists all the possible combinations of pipe schedules, which can be weld easily, is available. I am sure it will be difficult to butt-weld SCH 160 pipe with a SCH 40 and this cases is less likely to happen in practical life also.
Thanks for the reply

By dbigkahunna (****)

Date 09-18-2007 23:17

Typically 1/16 is the maximum without transition. I have put together 0.500 to 0.188 but it requires a machined transition for the heavy to thinner.
BABRT's

By ndshinde Date 09-18-2007 23:27

Thats what i am looking for. Thanks a lot. i am just looking if ASME code has any restriction for such kind of welding of pipes or fittings with two different thicknesses
Thanks

By CWI555

Date 09-19-2007 04:46

To my knowledge; the only limitation your going to find anywhere in ASME is related to pressure service. If pressures are not at issue, it is simply as JS55 stated, a factor of transition from thicker to thinner member. Assuming SH## May Explode varies in that as well depending on what part of the code your in.
I suggest getting more specifics for a more specific answer.

Regards,
Gerald

By ssbn727 (*****)

Date 09-19-2007 04:12

Hi Nand!

I could'nt agree more with Js55's post!!! I do remember vaguely somewhere in ASME B31.1 where they illustrate transition thicknesses, and bore angle tolerances but unless I look it up, I cannot quote you where to find it besides. you're query is referring to B31.3 so I'll just include a .pdf file which I'm sure will confuse you even more -that is unless you already read what Jeff posted. :) :) :)

If it helps any, especially if you do'nt have access to ASME B31.3 - Here's a .pdf file the might help you out:

http://engstandards.lanl.gov/engrman/6mech/pdfs/D20-AppA-ASME_B31.3-r1a.pdf

I hope this helps. :)

Respectfully,
Henry

By ctacker (****)

Date 09-19-2007 06:28

How about a new thread with all Henry's links? I find most if not all worth keeping for future reference!
Thanks Henry!

By RANDER

Date 09-19-2007 13:44

Forget "Ask Jeeves", Ask Henry!

By js55

Date 09-19-2007 14:15

Keep in mind that if you are welding differential sch's of pipe and you wish to match ID's in order to weld and reduce the transition what you are acutally doing is C(counter)-boring the ID of the heavy wall since increasing thickness will generally reduce the ID. Hopefully you have not cut the other end to dimension yet or you will lose your length as you C-bore.

By ssbn727 (*****)

Date 09-19-2007 21:13 Edited 09-19-2007 23:02

Hey fella's!!!

Thanks for the compliments but, are'nt we leaving a few names out???
The ones' that come to my mind are Aevald, the other Al: 803056, Chall, GRoberts, Swnorris with his always funny jokes and yet decieving expert knowledge in AWS structural fabrication issues, Js55, CWI555, Lawrence, John Wright, Chet Guilford, and Joe Kane when it comes to matters concerning AWS D1.1 & D1.5, Chall, My friend from across the pond in Germany - Stephan, Pipewelder1999, Professor Giavonni Crisi from a "First World" Country named Brazil, Yorkiepap, Dave Boyer, Brande who has always been there for me, and dbigkahunna with his API Knowledge, Medicine hawk, Bozaktwo1, Thirdeye, Jim Hughes,Tommyjoking, Kix, Bob Gardner, Gndchuck - A.K.A Charles Welch for his amazing looking underwater welding pictures, besides his knowledge & expertise in the subject, Sourdough for his blunt commentary and hardworking ethic that's second to none, and let's not forget one of the most helpful participants in here when it comes to Stainless steel and other materials as well involving their metallurgy, weldability and his way of making sense of it all for us to understand - the honorable Chuck Meadows, and good friend Jon 20013 who's always diligent & helpful when it comes to matters concerning ASME welding codes & standards the same goes for New Tito... Finally, where would we be at times without the help from Ken Coryell, Kip Mankenberg, or Marty Sims, Bmaas, Shane Feder's most interesting experiences from down under as well as Rodofgod's??? I almost forgot one of my favorites who always seems to inject wisdom at times when we could definitely use some: Bill Vanderhoof!!! I still Miss Niekie!!! oh well, I ca'nt remember everybody!!!:( Ohh yeah! Then there's Mblaha, Ron G., Molten Metal, JA who I think is Joseph Austrino or not?, Hogan, texredneck hwo has not been here for quite some time... That's it!! I done trying to include everyone!!! It's just too darn hard for this middle aged memory :(

I'm sure I left a few out but it was'nt intentional Believe me!!! It's more like, that's all my memory can recall these days because if it were 20 years ago, I'd know off the top of my head All of the participant's names in my all-time favorite Welding Forum - The BBS Grand Central!!! Besides, that "Butler" named "Ask Jeeves" does'nt even really exist as a person so how could I even attempt to compete with some of the world's most powerful sets of servers??? I do love using them to their ultimate potential however. ;)

Thanks again but, I respectfully disagree with you... Everyone of the folks I listed above off the top of my head, the one's I apologetically, forgot to mention, and myself are all spokes in this big wheel of knowledge and wisdom which makes this forum the place to go when one seeks answers regarding anything that has to do with the Art & Science of WELDING!!! We all deserve credit for all of our individual contributions here, and is what gives this special place such unity and singleness of purpose!!!

I can go on and on, and start to sound like one of those politician's out there but if I continued eventually, I would start to sound like a salesman selling snake oil to you so you can cure all that ail's you... However, that's NOT my style so, I'll end my post right here, right now!!! :) :) :)
Once again, thanks for the compliments but, the folks I mentioned above?
They all deserve equal billing too, including the ones I somehow forgot to mention. :) :) :)

Respectfully,
Henry

By ross

Date 09-19-2007 16:50

FYI You can always click on the poster's name (in blue at the top of the post), and that will take you to a screen that includes a blue link called "Posts," which will show you all the posts ever made by that person.

Ross
AWS Marketing