Welded connections for aluminum

[broekie]

I am having trouble coming up with allowable stresses for welds in aluminum connections. I have the 2000 Aluminum Design Manual, but there is no information in there regarding welded connection allowable stresses (unless I am missing something), only welded built-up members. I know the member changes allowable stresses if it within an inch of the weld, but I can't find anything on the weld itself.

Does anyone have any information on this topic or can you steer me in the right direction?

 

[ishvaaag]

You can see the thing discussed with examples in

Aluminum Structures
A Guide to their Specifications and Design
J. Randolph Kissell and Robert L. Ferry

Wiley Interscience, John Wiley and Sons 1995

 

[CWIC]

Also check out Aluminum Design Manual: Specification for Aluminum Structures by the Aluminum Association.

 

[ERV]

What you may be looking for is "Structural Welding Code-Aluminum" , AWS, D1.2-97:

http://www.aws.org/catalogs/index.html

Try this link for any welding code or standard.

 

[CWIC]

ERV:
The D1.2 codes' section on design is minimal, about 3 pages. The reference I noted above is noted in the D1.2 code in Section 2 - Design of Welded Connections.

 

[bvi]

If you weld aluminum, you basically need to use the properties of annealed aluminum in the vincinity of the weld.

 

[boo1]

What alloy and rod are you using? Ill look it up for you.

Cheers

 

[dozer]

broekie,

It is in the 2000 Aluminum Design Manual. Sorry, I'm at home so I don't have the ADM handy. If I remember next week when I'm at work I'll tell you the section. (In other words your out of luck.)

I think I've seen you post several questions about aluminum so I assume your new to its design. Let me give you some advice on aluminum welding . . . don't. Just kidding, but seriously, where I work we avoid welding critical members like the plague. Our shop makes racks to store material for themselves (not sold) so they are not "engineered". I don't think I've ever seen one without a crack in at least one weld. FYI, the material is 6061-T6.

This is just anecdotal evidence to file in the back of your brain. Yes, I've been to the Smithsonian and NASA and have seen the beautiful aluminum welds on critical components like rocket engines, so it must be able to be done correctly. I'm just saying be careful 'cause it can sure be done incorrectly.

 

[Ron]

broekie...the info you're looking for is contained in Table 3.3-2 of the 2000 ADM. It varies with alloy. The stress reduction applies to an area within 1 inch of the weld. Note that there are several little nuances of the allowable stress application for welds as noted in Section 7 of Part 1A of the 2000 ADM, such as for sections with weld on part of the cross section, etc.

Good luck.

For two common alloys, 6061-T6 and 6063-T6, the allowables are 15 and 11 ksi respectively, but again, you should check the provisions for applicability, as thickness, proximity, and other issues may prevail.

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**Try this course...

http://pdhonline.org/cgi-bin/quiz/courses/courselist.cgi?class_name=p112

 

[Lutfi]

\Always remember that the allowable stress within one inch from the weld is considerably smaller than the rest of the structural element. This is due to strength loss due to (loss of heat treatment) due to welding.

 

[boo1]

What is 2000 ADM?

 

[broekie]

Thanks to everyone for your help. Between tables in Chapter 3 and Chapter 7 in the ADM, I think it has what I am looking for. I was confused as to whether those tables were for connections between two different members or for the welds of built-up members. We are finding some fatigue issues anyway, so we will probably be going to bolted connections. (This is for highway sign connections to bridges).

boo1, 2000 ADM is the 2000 Aluminum Design Manual.