details of weld size in drawings . . .?

By shubyjames Date 04-07-2011 17:16

I hope this the right section of the forums to post this . . .

I am trying to provide a detailed drawing of sections of skewed mechanical tubing (round) connections. I can’t find how to determine weld size or weld symbol (if one applies) to convey design requirements. Most round tubing we use has a wall of anywhere from .0625” to less than .1875”. The AWS specs we have do not deal with hollow connections, and other publications I’ve viewed deal mainly with structural tubing which have far greater wall thicknesses then we deal with. Can anyone provide some input or direct me to any publication, spec, or books that deal solely with mechanical tubing (round and square). That will show how to choose weld size, symbol, etc so we could properly convey joint connections on our drawings. And when it comes to drawing a detail of a skewed joint, it will be properly represented with the right dimensions and any other data needed to weld and inspect. I hope this makes sense because I’m using the least amount of words to describe a major headache. :mad:

Thanks,
Jim

By jwright650 (*****)

Date 04-07-2011 17:22

Hi Jim,
Welcome to the forum.

Can you post a sketch of your connection?...I'm picturing one thing in my mind, but a sketch or dwg may help determine what welding symbol you may need....as for the weld sizes, that is more of an engineering question.

By shubyjames Date 04-07-2011 18:15

Maybe I could explain it a little better. Picture 2 equal diameter tubes (1.5” for illustration) forming a Y joint that has been coped to fit. Because the plans change I just can’t call it a fillet, or a fb, or a square. What is the proper way of conveying a weld size all around? Is it based on the throat centerline? My actual case consists of a step. I have a 1.25” diameter base with a .75” dia branch at a 45 degree angle. The wall thickness of the .75 is about .0625, and the base is about .120 wall.
Hope that helps

By fschweighardt (***)

Date 04-07-2011 18:51

I know where you are coming from, you go from an acute tee geometry to a slightly obtuse, to a really obtuse as you travel around the branch. I have broken the weld up into segments depending on the geometry (where it changes from on to the other by code definition), and specified the weld in each segment.

By shubyjames Date 04-08-2011 13:15

Thanks for the input. A couple of questions for you. . . When detailing, do you divide your weld into toe, heel, and sides? Do you use an actual weld symbol or a welding symbol to callout a detail dimensioning the weld sizes. I understand that situations vary but I guess I’m looking for a path to follow.
Thanks again

By fschweighardt (***)

Date 04-08-2011 13:25

exactly, you end up with 3 weld symbols i each for toe, heel, and sides. Usually standard symbos and proctices suffice to spec the weld, stuff like Z-loss, specify leg, or effective throat, etc and so on. SOmetimes if it gets too weird, I draw a cross section of the weld and tell the vendor that he needs to make a weld as drawn.