Flare-Bevel Weld Effective Throat When Not Welding Full Depth of Groove

[Ron247]

Not that I cannot weld the full depth of the groove for a Flare-Bevel weld, but assuming I did not want to, how do you calculate the effective throat? I have not found any actual examples.

In my case, I have a 5/8" diameter round rod to be welded to a flat plate. If I only wanted to go up 1/4" from the center of the rod and not the 5/16", what would I look at to calculate the effective weld? What 2 points do I measure from?

I know the full depth weld would be (5/16)*R = .0977.

 

[SJBombero]

I would guess that there are no examples because it is so rarely done. A flare-bevel is only prequalified if it is filled flush. Anything less than flush would require the fabricator to qualify a procedure. equivalent strength, and the welders. You would need to be laying down a LOT of weld to justify the process of qualification. I imagine it is less costly just to add the extra weld even though it is oversized in most cases.

 

[ProgrammingPE]

The effective throat of a PJP groove weld or flare groove weld filled less than flush shall be as shown in Table J2.1 or Table J2.2, less the greatest perpendicular dimension measured from a line flush to the base metal surface to the weld surface.

Effective throat = (5/16)*R - [Underfill Dimension] = 5/16*5/16" - (5/16"-1/4") = 0.035"

Here's a picture of a Flare-V Groove Weld showing the dimension from Steel Design Guide 21 (you have a flare-bevel-groove weld, but the dimension is still the same):

@pvchabot is correct, though, that if you specify a thickness other than filled, you will no longer be permitted to use the Prequalified Welding Procedure Specifications so will have do to tests for those welds.

...flare-bevel groove welds BTC-P10 and B-P11 minimum weld sizes shall be calculated from Figure 3.3.

(Figure 3.3 shows the same dimensions for the weld size as AISC 360-16, Table J2.2)


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[Ron247]

Thanks for the responses. I am not trying to use less weld, but was curious how the throat was calculated. I cannot see it being the same as the flair V-groove since the connection is not a mirror image. I can see the Flair-V being straight up but not the Flair Bevel. The 5/16 coefficient on the Bevel versus the 1/2 on the V-groove indicates to me there is some difference. It seems to me the throat would be running on some angle but I do not know from where.

I rotated a line from the highest point on the flat plate that the weld was placed to the surface of the round. I calculated several locations and took the one with the least length. It was about .08 versus .0977 for full. But as the posts indicated, I made this method up, I did not see it noted that way in some reference. The .0977 for full throat, where does that line exist on the actual weld of fully filled connection? I have never seen a sketch of that either.

 

[ProgrammingPE]

The effective throat dimension for the flare-v groove weld is larger than for the flare-bevel groove weld since the weld is able to get deeper into the narrow space between the two materials (the point of the V) since both sides are curved so it gets wider sooner.

The dimension you are looking for is from the point of the V to the other edge of the weld since this is the cross section where all the stress is carried by the weld alone.

Effective Throat for Flare Bevel and Flare-V Groove Welds

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[Ron247]

Thanks a lot. That clears up my main questions.