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Up Topic Welding Industry / Technical Discussions / How to draw welding diagram
- - By Maggs47 (**) Date 06-06-2017 22:33
I've got a tube to fitting weld that I need to draw a weld diagram for.  The tube is 2" OD x 028 wall.  The fitting is 2" OD x .035 wall with a bevel on the inside down to .020-.025 root face.  The weld will be all around from the outside of the tube.  I don't know if this counts as a square butt (what the welder will see) or a single bevel.  I'll attach an image of a close-up of the joint.  Weld would be from above.
Attachment: WeldJointClose-up.jpg (3k)
Parent - - By Tyrone (***) Date 06-07-2017 11:09
Hey Maggs,
From what you described, here's what I think the weld symbol should be.  The "x" is the required depth of penetration.
Parent - By Maggs47 (**) Date 06-07-2017 15:12
Thanks.  That's where I ended up as well.  Its a melt through, so i added the filled dome above the square groove symbol.
Parent - - By welderbrent (*****) Date 06-08-2017 00:14
From your post and attachment I would concur with Tyrone but I have a question, or two...

So you have a tube with a wall thickness just less than 1/32" and a fitting with a wall thickness just over 1/32" that you are putting a bevel on? 

I would presume the bevel is to help avoid turbulence of some kind though I have trouble picturing that in my mind on such thin parts.  The weld penetration will give you more turbulence than the difference in the wall thickness would.  It is only .0035 per side. 

My questions: What code are you using?   What process are you using?  What material are you using? 

Can you tell us more about this project?  I am intrigued. 

He Is In Control, Have a Great Day,  Brent
Parent - - By 803056 (*****) Date 06-08-2017 01:26
Its a weld around a round part, so technically the weld all around symbol is not needed. The weld is CJP and as stated a melt thrugh symbol is added to the other side, so the weld size can be omitted. When the bevel and the weld size are not included, the weld is assumed to be CJP. The melt through symbol is a nice added touch.

The counter bore and taper on the ID is a nice touch if both the thin wall and the thick wall are concentric and the same thickness. I concur with Brent, that it is not ideal to have a bevel that is "thinner" than the thinner member. It may promote incomplete fusion where the bevel is located. A couple of mock-up will tell whether the counter bore and taper is actually needed.

A "0" root opening and purge will go a long way in ensuring the weld is just what you are looking for.

Best regards - Al
Parent - - By Maggs47 (**) Date 06-08-2017 15:16
We will be welding this per BAC 5975 (all aerospace work over here).  It is a GTAW weld on 6061-T6 aluminum.  I agree that the inside bevel isn't ideal, but that's the design of the stock Hydraflow fitting.  The OD is the same on both components, so the difference in wall thickness only shows up on the inside.

I will definitely have the welder perform a nice, long purge.  I've been trying to promote purging a little longer than they think is necessary.  Since we aren't a particularly high throughput shop, I'd rather err on the side of caution.  We have to qualify the weld with penetrant and X-ray examination, so I'll definitely know if we get CJP.  I'm thinking the bevel might even help us see the penetration better before we start in on NDT.
Parent - - By welderbrent (*****) Date 06-09-2017 00:51
Interesting.  Would love to hear how it turns out.

BB
Parent - - By Lawrence (*****) Date 06-09-2017 12:49
I agree with Brent... Would like to see how this turns out.

That is a tough weld and operator torch angle is going to be the key.

Don't understand the reason for the argon purge.
Parent - - By Maggs47 (**) Date 06-09-2017 15:05
Argon purge to prevent oxidation on the ID because the heat will get there before the material melts.
Parent - - By 803056 (*****) Date 06-10-2017 03:28
Aluminum is often welded without the benefit of an inert purge. The aluminum oxidizes immediately forming an oxide that melts at a higher temperature than the aluminum base metal. Once the oxide is formed, it acts as a protective layer.

Consider: pure aluminum melts at about 1220 degrees. Aluminum oxides melts at around 3200 to 3600 degrees F.

Al
Parent - - By Maggs47 (**) Date 06-12-2017 15:27
The oxide continues to grow with time, and even faster at an elevated temperature.  The purge is to help fight against oxide growth as the metal heats.  I agree that it isn't always necessary, but our shop seems to consistently have problems with incomplete fusion on aluminum joints, so I try to do anything I can from the weld schedule side to help them succeed.
Parent - By 803056 (*****) Date 06-13-2017 02:48
It is tough to argue with success.

Al
Parent - By 357max (***) Date 06-15-2017 21:27
Would this be a transition? versus a groove preparation?
Up Topic Welding Industry / Technical Discussions / How to draw welding diagram

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