Welding Tips and Tricks

Hi Guys
We are about to start the next project stage and have hit a bit of a wall. We have searched for a while but have not had any success so to speak with finding out any real life data on this material.
We are welding two sections of 6082 together but are using some plate in between the two as load displacement bearing. In the past we have used 6061 which has worked perfectly. However for the next project we cannot get this in a wide enough extrusion (and we aren't getting a mill run done for one job ). We have played with a bit of 5005 H34 and it bends up perfectly for the application. However we are a little concerned with it's sheer strength. The load isn't huge, we are talking 3500lbs over 8 mounting points, not big by any means.
Structure will be pulse mig welded with 5356F, and termination welds are all TIG'd.
It's hard to describe as we have our hands tied with red tape, and pic's are defiantly not possible. We do have metallurgist associated with the project, but they are very hard to get a hold of and take many days to get back to us, when they do. And as usual we are behind on this so need to move ahead.
What sort of loads would the 5005 H34 take realistically before starting to shear. All materials are 1/4".

Thanks in advance for any help or links people can provide.
Cheers

Without photos or specific details, your question is very hard to answer.
It would be best to consult with a structural engineer for your application.
http://www.suppliersonline.com/propertypages/5005.asp

My employer also forbids "recording devices", yet provides me with a very nice notepad and pen. Viola'..."Recording device"!!!

Take some notes, make a sketch, scan or photograph it at home (be carefull of identifiable details), and post it up.

My "gut reaction" is that you're fine... The heat effect on a successful weld on that heavy a section of 6061 would likely have "finished" properties similar to the 5005, but the devil is in the details.

Steve S

I am thinking you will be fine. Obviously the 5005 will be the "weak link". The only thing that would concern me is the 6082 is used as a structural alloy while the 5005 is more for aesthetics . I would also guess that this was specified by the customer and hopefully they already know this will work. Without a picture, I would have to say if the 5005 is in a shear load, the material itself will separate from the weld if it were to fail. If this is a concern maybe a re-engineer is in order. With 3500lbs spread out over 8 mounting holes, it is possible (if not engineered correctly) the holes would rip out first, although not likely.

Here is some more info for your reference.
5005
http://www.asecoltd.com/userfiles/clipa ... 205005.pdf

6082
http://www.wilsonsmetals.com/datasheets ... 1_148.ashx
http://aws.org/wj/supplement/WJ_1983_09_s243.pdf

And for fun...
http://www.aws.org/wj/supplement/04-2004-HUANG-s.pdf
-Jonathan

Haha, I thought my descriptions of a thousand words was worth one pic haha.

Hi Otto, yea sometimes the red tape can be a pain in the ass, I don't have the CAD on the home computer so MS paint to the rescue.

The black is heavyish C channel ( 6"x2-1/2") in 6082, the red is the 5005 H34 which is fully welded around the perimeter in a single pass pulse, and the blue is the 3" box in 1/4" 6082. The 5005 plate is about an inch wider both sides than the box so as to not to localize the heat.
We wern't worried too much about the 6061 softening during welding as we sit the structure outside for a week after welding to allow it to naturally temper. It was the fact that the 5005 would not harder any further after welding was niggling at me. All the weight is downward on the 3" box as the crayon pic sits.
The more I think on it the less worried I am about it, it was just one of those moments when the project was deviating away from the normal, change from proven processes worries me sometimes.
Cheers

NT Unique,

Studying the drawing, I'd say the 5005 serves a specific purpose, perhaps as a sort of "shock absorber", an alloy that won't work harden under vibration. A dampner, so to speak. This layout is clearly not arbitrary.

I think you're right to relax... Yes, it's not something I've encountered, perhaps not the "normal", but your rendering suggests it's well thought out.

Steve S

By the way, NT Unique,

I don't automatically trust "engineering" either, when what I'm presented with doesn't match my experience and/or expectations.

Questioning such things before putting your name on the weld is ALWAYS a good idea.

Steve S

Hi Otto
Thanks for your input, I appreciate and respect your advice and knowledge. So was hoping you were going to weigh in on this.
Oh by the way, I really should end my posts with my name seeing as I'm not a real regular on here.

Cheers
George

George,
I can't add to the discussion on 5005 but I will comment on the last part of your statement. I think everybody should use their first name in their posts, that way it seems like a more personal conversation, and I don't have to remember some 25 letter username, I'm getting old. Besides, George is a fine name, I know of as least 2 members here that use it for our middle name (GreinTime).

Len