American Welding Society Forum
This may seem simple. It's been a while since I've been asked a question regarding the ASMEs.
Regarding the the set-back call out for socket welds. The min call out is 1/16" Per Fig 328.5.2B, B31-1-2002(Sorry old Rev).
The question was put to me this way. What is the MAX set back allowable.
(IMHO) A good craftsman would want to maintain as close to the Min as possible to maintain the best structural integrity. However, that is not how the question is being asked.
Thanks in advance for your input.
I am pretty sure there is no max - according to code.
I have worked for a few clients who had a requirement of "from 2 to 3 mm" LMAO
How does it give structural integrity the deeper it goes?
I could not find anything in the codes referring to a "MAX allowable gap" either.
Seems the worse case scenario for max gap would be 1/2 the depth of the sock-o-let on both ends of "boxed in" run. Jam the pipe in one end of the run, then barely clearing the opposite end, insert the pipe 1/2 way into the other end. Splitting the distance between the two.
There is no max only a min. Though the job specs. will tell you I would say, but if they don't there is no max distance.
If you read it closely, there is neither a minimum nor a maximum specified, only a nominal dimension that must be met. The words say to withdraw the pipe "approximately 1/16 inch". I would say 1/4 inch or even 1/8 inch is not "approximately 1/16 inch".
Here's what B31.1 says in 127.3(E):
(E) Socket Weld Assembly. In assembly of the joint
before welding, the pipe or tube shall be inserted into
the socket to the maximum depth and then withdrawn
approximately 1⁄16 in. (2.0 mm) away from contact
between the end of the pipe and the shoulder of the
socket [see Figs. 127.4.4(B) and (C)]. In sleeve-type joints
without internal shoulder, there shall be a distance of
approximately 1⁄16 in. (2.0 mm) between the butting ends
of the pipe or tube.
The fit between the socket and the pipe shall conform
to applicable standards for socket weld fittings and in
no case shall the inside diameter of the socket or sleeve
exceed the outside diameter of the pipe or tube by more
than 0.080 in. (2.0 mm).
My reading of this is that the words "shall be inserted into the socket to the maximum depth and then withdrawn approximately 1⁄16 in. (2.0 mm) away from contact between the end of the pipe and the shoulder of the socket" do not suggest it would be acceptable to withdraw the pipe more than "approximately" 1/16 inch prior to welding. No tolerance range is provided by B31.1, but I would say +/-1/32 inch is reasonable.
Many clients specify a minimum gap after welding. I can see a reason why there should be a maximum. If there is only the fillet weld holding the joint together the stresses from a bending moment will be greater on the fillet weld as compared to a pipe inserted deeper into the socket. When bending the pipe will contact the fitting internal surface and reduce stress on the fillet weld. Only my opinion.
A member of the piping committee once told me there is no minimum dimension for the engagement of the pipe into the socket (fitting or flange). There simply has to be enough engagement to ensure a sound fillet weld can be deposited all the way around the hub without burn-through. The fact that the pipe extends 1/8 inch, 1/4 inch, or 1/2 inch into the socket does not influence the strength of the welded joint.
Sounds reasonable to me when you think about it.
Best regards - Al
Powered by mwForum 2.29.2 © 1999-2013 Markus Wichitill