Weld C6x8.2 perpendicular to TS6x3x3/8

[pmkPE]

I would like your opinion regarding the potential impact of welding a C6 perpendicular to a tube steel member (C6x8.2 - TS6x3x3/8), the 6" dimensions match up. Assuming an equivalent weld size of 3/16" on both flanges and the web a direct weldment qualifies. One specific is that the weld on the top flange must be flush with the two members; this eliminates a plate that extends above the TS/C6. A flare bevel weld on both flanges results in an effective throat of more than 3/16" (5/8 x (t=.375) = .23" (per AWS D1.1, figure 3.3).
Even with an interstial plate between the channel and the tube wall the effective throat would be the same and adequate. I performed a rough check on the punching shear of the tube's wall using criteria in the AWS D1.1 and it checks out OK.

Does anyone have any anecdotal comments regarding similar joint configurations? One concern that I have is that the radius on the tube corner can range from less than the thickness of the wall to as much as three times the thickness, therby increasing the gap between flange and tube.

I would appreciate hearing from you, thanks in advance :>)

 

[JStephen]

You mean you're welding the back of the channel against the tubular piece?

One thing is you may get some weld distortion that will tend to curve the piece toward the channel side.

One thing to watch is that the outside radius of the tube can vary with manufacturer, which changes your weld geometry.

 

[Lutfi]

I think he is talking about welding a C6 perpendicular to the Tube steel. I see no issues with it. Check on the radius of the tube corner and make sure that the weld is that you will achieve is structurally is adequate. If the weld overfills the gap, it can be ground smooth to achieve the flush surface that you desire.

If the C6 is only carrying shear, you need not to weld the flanges. Fillet welds on both sides of the web will do.

Regards,


Lutfi

http://www.cdeco.com

 

[JStephen]

"the 6" dimensions match up"
"the weld on the top flange must be flush with the two members"

Those two lines made me think the channel was beside the tube, which is why I asked.

 

[pmkPE]

Thank you JStephen and Lutfi for your consideration, the C6 is to be welded to the TS to form a "TEE", i.e. two members at 90 degrees. Stating the match-up of the 6" dimensions was to indicate that the flanges of the channel are to be even with the top (or short sides) of the TS6x3.

 

[DaveAtkins]

Is the C6 "pulling" on the wall of the tube? Then I would be concerned with bending of the tube wall. It might be better to weld the channel flanges to the tube corners, and ignore the contribution of the channel web to tube wall weld.

DaveAtkins

 

[pmkPE]

DaveAtkins,
I have checked the stresses in the tube wall through use of the procedure in the AWS D1.1 for punching shear. Stresses are reasonably low. What my concern is are there any other issues (that I have not addressed in my initial post) that would negatively impact the joint connection.

What I mean to say is that I don't know what I don't (but should) know. :>)