Welding round bar to pipe 2

[mickAA]

I want to weld round bar (3/8" dia. H.R) to SCH. 40 pipe (1 1/4"), joining outside wall to outside wall so both pieces are running parrallel using FCAW.

My only concern is welding different diameter pieces together and getting the proper penetration.

1) Am I right in specifying a Flare V groove? If so,
2) Does AWS D1.1 apply? In particular Table 2.1 for selecting effective weld size and 4.10.5 qualifying this weld?

If not, can somebody point me in the right direction?

 

[Ron]

What is the application? If non-pressure, no petroleum product or no potable water, then AWS is appropriate, even if non-structural.

Flare V is about as close as you'll get, but with your description, I doubt you'll find a pre-qualified joint designation.

I would probably use SMAW as the penetration for this configuration would be a bit more controllable and I think you could get more weld deposition with less heat input, so distortion might be a bit less.

 

[racookpe1978]

With ANY "round-to-round" weld you will be unable to get "penetration" (melting) all the way through the joint.

That won't matter for "shear strength" and for resistance to ending/torsion forces since you will merely need to use a joint with enough weld material so the two materials will hold together. (Kind of like the calc's for a fillet weld - the weld needs to be large enough to carry all the forces, since the two surfaces are not melted into each other.)

But if the two surfaces are exposed to any kind of corrosion, the small voids behind the round-to-round weld will catch the corrosion products, or the corrosive liquid droplets, and trap them behind and below the weld. You may need to strongly consider requring a "seal weld" around the whole welded surface so there is no path from the outside to any pit or void below the main weld.

You won't want to include the seal weld in your strength calc since it is an irregular surface following an irregular path around the pipe, but you will need it before you try to paint the assembly.

 

[mickAA]

That wasnt a very good explanation. (My 1st post on here).

The set up is purely structural. I've attached a partial sketch of the orientation of the welds. I've shown them in tension but there is a possibility for a 10000 in.lb torque to be present.

Very good point racookpe1978, "the small voids behind the round-to-round weld will catch the corrosion", as there is the chance for super-saturated NaCl (pH = 4.0) to become trapped.

AWS D1.1 doesn's reference this type of weld (from what I've read) so I am assuming I will have to get it qualified but I'm unsure of an effective weld size due to the unequal geometries of the pipe and bar.

 

[stanweld]

What you have described fits a flare groove weld. Weld sizes must be defined to meet the torsional loads. Welding all around will limit the possibility of voids.