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Welding a pipe beveled end with SW elbow is possible?
- Thread starter danirem
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danirem,
Your question:
Is it possible to weld a beveled end pipe to a SW elbow?
The answer is Yes it is possible.
The only issue is, is it the right thing to do?
- Did you deliberately bevel the end of the pipe for this purpose?
- Or was it a case of the piece of pipe that was handy just happened to already be beveled?
- What is the commodity in the line?
- Is it a fluid that could cause problems because there is a slightly larger gap in the socket?
There are all kinds of questions and the answers to them could justify doing it or not doing it.
Sometimes its possible to do all the right things and still get bad results
Your question:
Is it possible to weld a beveled end pipe to a SW elbow?
The answer is Yes it is possible.
The only issue is, is it the right thing to do?
- Did you deliberately bevel the end of the pipe for this purpose?
- Or was it a case of the piece of pipe that was handy just happened to already be beveled?
- What is the commodity in the line?
- Is it a fluid that could cause problems because there is a slightly larger gap in the socket?
There are all kinds of questions and the answers to them could justify doing it or not doing it.
Sometimes its possible to do all the right things and still get bad results
It is acceptable to use bevel ends assuming that the service conditions are acceptable.
In assembly of the socket joint before welding, the pipe or tube is inserted into the socket to the maximum depth and then withdrawn approximately 1/16" away from contact between the end of the pipe and the shoulder of the socket. The bottoming clearance is to reduce the residual stress at the root of the weld that could occur during solidification of the weld metal, and to allow for differential expansion of the mating elements.
The expansion gap and internal crevices left in socket welded systems promotes corrosion and make them less suitable for corrosive or radioactive applications where solids buildup at the joints may cause operating or maintenance problems.
Socket welding systems are unacceptable in food industry application since they do not permit full penetration and leave overlaps and crevices that are very difficult to clean, creating virtual leaks.
In assembly of the socket joint before welding, the pipe or tube is inserted into the socket to the maximum depth and then withdrawn approximately 1/16" away from contact between the end of the pipe and the shoulder of the socket. The bottoming clearance is to reduce the residual stress at the root of the weld that could occur during solidification of the weld metal, and to allow for differential expansion of the mating elements.
The expansion gap and internal crevices left in socket welded systems promotes corrosion and make them less suitable for corrosive or radioactive applications where solids buildup at the joints may cause operating or maintenance problems.
Socket welding systems are unacceptable in food industry application since they do not permit full penetration and leave overlaps and crevices that are very difficult to clean, creating virtual leaks.
racookpe1978
Nuclear
The configuration of the pipe stub end inside the socket weld means that the joint stress "flow" is from the pipe wall through the fillet weld around the pipe into the end of the socket fitting of the elbow, then down into the socket weld fitting wall and around the corner.
Thus, the very end of the outside of the orginal pipe wall - which has been removed by the butt weld pipe preps in your case - does not "see" any of the pipe weld stress that is coming through the joint.
However! If your pipe wall is very thick, or the butt weld pipe wall prep is ground improperly (so the current prep IS going to be welded over), then you MUST fill out the pipe wall (butter it up to near-nominal in the vernacular) BEFORE fitting up the joint as described above. Remember to account for and maintain the 1/16 to 1/8 gap between the end of the pipe and the bottom of the socket weld fitting before welding begins..
Thus, the very end of the outside of the orginal pipe wall - which has been removed by the butt weld pipe preps in your case - does not "see" any of the pipe weld stress that is coming through the joint.
However! If your pipe wall is very thick, or the butt weld pipe wall prep is ground improperly (so the current prep IS going to be welded over), then you MUST fill out the pipe wall (butter it up to near-nominal in the vernacular) BEFORE fitting up the joint as described above. Remember to account for and maintain the 1/16 to 1/8 gap between the end of the pipe and the bottom of the socket weld fitting before welding begins..
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