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Up Topic Welding Industry / General Welding Discussion / Edge joint detail, which one is better?
- - By Metarinka (****) Date 01-15-2009 21:38
This has been bugging me for awhile as I've never heard a satisfactory answer one way or another.

When detailing and edge joint often times the edges will be offset (bottom sketch), so as to form a natural 45 degree included angle groove weld.  This saves on joint preparation costs as the edges often need no grinding and depending on the process and material thickness full penetration can be achieved with little to no difficulty.

however the "standard" practice for outside corner joints is two butted members (top sketch)  followed by beveling of some nature in order to achieve full penetration.

I have heard of an objection to using the offset detail due to the susceptability to bending forces about the root, indicated by the arrow. Is there any rule of thumb or guide to the application of either joint detail?  From a welding standpoint you can save a lot of time if the edge does not need to be beveled, but from a mechanical standpoint I'v always been interested to know if this is as strong as a traditional edge joint.
Parent - - By Metarinka (****) Date 01-15-2009 21:51
more day-dreaming... if the offset edge weld acts as a fillet weld, then the normal means of failure would be shear across the depth of the throat. However If a force is applied in the plane of the base material than the  it would transmit through the weld at perpendicular to the weld throat. Would that affect how the weld fails and it's design strength?
Parent - By DaveBoyer (*****) Date 01-16-2009 04:30
     Corner to corner is trickey to set up accurately if the parts are not fixtured, and there is the problem of getting full penetration without burnthrough if using low skill operators.

      I think with this corner to corner joint the ammount of weld reinforcement will be a greater variable due to operator skill, and will have a bearing on strength.

      I think that the traditional joint with proper edge prep for full penetration will be stronger in regard to the bending You mentioned , as there is more material in the outside corner.

       This is just what I think and worth what it cost You, I do eyeball engineering and work to FC 2002.
Parent - By bozaktwo1 (***) Date 01-16-2009 12:40
My somewhat uneducated mind would think first that the joint design selection would be based primarily on the material type and thickness, and then perhaps its potential application.  The bottom sketch, for instance, would be completely acceptable for cosmetic sheet metal work.  I prefer the joint design in the top sketch for anything structural, with a bevel in the horizontal member to aid penetration, and a fillet in the backside corner.  Of course, with some materials, this might not be advisable, such as on heat treatable aluminum alloys, where you must carefully control heat input.  Just my two pennies.
Parent - - By G.S.Crisi (****) Date 01-16-2009 18:47
I'd like to post another sketch, but I don't know how to do it.
Giovanni S. Crisi
Sao Paulo - Brazil
Parent - - By 803056 (*****) Date 01-16-2009 21:43
We worked through this same application several weeks ago. I bet we can find the thread with sketches somewhere.

Best regards - Al
Parent - - By 803056 (*****) Date 01-16-2009 21:52
Well, it wasn't the same problem, but similar.

Look at the discussion in this thread: http://www.aws.org/cgi-bin/mwf/topic_show.pl?pid=93971;hl=corner%20joint%20burn%20through

Best regards - Al
Parent - By Metarinka (****) Date 01-20-2009 18:09
thanks al, I remember looking at that post before, but unless I missed something it was more on whether the above detail is a groove weld or fillet weld
Parent - - By darren (***) Date 01-18-2009 04:33
do you have the sketch saved in your puter somewhere
if you do then ill try and walk you through it
darren
Parent - - By G.S.Crisi (****) Date 01-19-2009 20:12
Thankyou, darren, but I havn't got the sketch in electronic format, just printed.
Giovanni S. Crisi
Parent - By darren (***) Date 01-20-2009 11:40
well you could scan it into your puter.
or fax it to you puter if your set up for that.
you must have a great number of computer savvy individuals at your university.
or worst comes to worst mail it to me and ill put it on ;)
Up Topic Welding Industry / General Welding Discussion / Edge joint detail, which one is better?

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