Fillet weld to pipe/round HSS 3

[phamENG]

Quick question - what are the limitations on a fillet weld to the side of the pipe? Particularly the diameter of the pipe. Welding a 3/8" plate to the side of an 8" round HSS probably isn't an issue, but what about to the side of a 3" pipe? The tighter radius creates a larger "angle" and the joint starts to look like a two-sided skewed fillet.

My thought is that it would be specified as a fillet but with the throat called out rather than the leg. For example, if I wanted a weld to develop the strength equivalent to a 90^o fillet welded joint, I would put (0.178) in the weld symbol rather than 0.25 or 1/4. Sound about right?

 

[CANPRO]

I think you're reasoning is correct. You could figure out the angle between plate and a line tangent to the pipe and use that as your "skewed" fillet angle. Outside of certain range of angles it will become a PJP. Specifying the required throat sounds like a good idea for design drawings, but for fabrication purposes I'd probably specify the leg size of the fillet.

 

[phamENG]

Thanks, CANPRO. These are design drawings, so I want to make sure my design intent is clearly conveyed and I'll let the fabricator's detailer translate it to the welder in the shop.

 

[dauwerda]

This is definitely a bit of a grey area as its a T-joint that has its parts meeting at 90° but as you get further away this angle increases, and just what the angle is depends on the overall size of the weld. AWS D1.1 indicates the following:

For fillet welds and skewed T-joints, the following shall
be provided on the contract documents.
(1) For fillet welds between parts with surfaces meeting
at an angle between 80° and 100°, contract documents
shall specify the fillet weld leg size.
(2) For welds between parts with the surfaces meeting
at an angle less than 80° or greater than 100°, the
contract documents shall specify the effective throat.

I would say you are taking the correct approach by specify the required effective throat.

 

[phamENG]

Thanks, dauwerda. I appreciate the confirmation.

 

[JStephen]

Part of the length could also be a "Single-Flare-Bevel-Groove" weld or "Double-Flare-Bevel-Groove" weld per the weld symbol book.
If you don't know how to put down the symbol, there's a good chance the person at the other end doesn't know how to interpret whatever symbol you come up with- and in that case a drawn detail or brief note as to the intent may be more helpful than the symbol itself.

 

[phamENG]

JStephen - sorry, a better description of the joint would have helped. Think shear tab on a pipe column. A t-joint, not a plate running past the pipe (which would absolutely be a flare bevel).

Thanks for your input.

 

[Agent666]

I'm just curious if people are mixing leg and throat definitions on drawings as suggested by AWS then how are ensuring that the two types of dimensions are being interpreted correctly? As it relies on the detailer and fabricator knowing this subtle difference (which I'm not convinced all would?).

 

[phamENG]

Well I certainly hope they do. Specifying a fillet weld by leg would be specifying by SIZE, which is indicated on the Standard Location of Elements of a Welding Symbol diagram as being S. Effective throat is (E). So, if I draw a weld symbol with 1/4 on the line next to my fillet symbol, I mean a 1/4" leg. If I do it with (1/4), I mean I want a 1/4" throat. Granted, that should only be applicable for skewed joints below 80 and above 100 degrees - or this seeming gray area.

As for whether or not it will be properly interpreted...I don't know. Hopefully the parenthetical notation will be enough to force an RFI out of the fabricator if they aren't familiar with it.

 

[dhengr]

PhamENG:
I’d show both, .25” and (.177” min.) with an ‘S’ below the .25” and an ‘E’ below the (.177” min.). I’ve never been bashful about using the symbol tail area to write a short book if it would help clarify things. I’ve also drawn a full size section through the immediate weld and shown the weld shape and dimensions in more detail, than a straight 45° line. The .25” leg is measured w.r.t. the face of the shear pl. and the .177” min. is dimensioned from the weld root. Show and .177” rad. arc from the root to represent the min. throat, and you see/show that a convex weld shape can arc down to the pipe face and will provide the req’rd. throat, and the detailer and welder can see that too. This can easily be inspected with a fillet weld gage, with the shear pl. face as the ref. plane. And, I don’t think it should generate a RFI, or be misunderstood. Also, draw yourself a full size section through your 3” pipe and a .5” shear pl. or a .75” shear pl., and at the root the opening is still within the fit-up allowance, thus no flare-bevel. For a 1” shear pl., I’d detail it (have them) grind a .125” bevel on the two edges of the shear pl., and then show the weld like a bevel weld with a fillet reinf’mt., fill the bevel and then build the fillet, essentially as above. I’m trying to show my intent, not exact AWS Symbols perfection.

 

[skeletron]

Agree with @dhengr: use the tail area to write any clarification. The fabricator should (...and most likely) will know the specifics of weld nomenclature.

 

[phamENG]

Thanks. Sage advice, dhengr. I'll certainly use it.