Weld across the Flange 1

[JAE]

With a steel beam we've always been very careful about trying to avoid welding across a beam flange while it is under stress and carrying load.
The theory is that if you weld across the flange, you introduce excessive heat that can possibly affect the entire flange and possibly cause collapse.

The question we have is:
1. Is there a specification or AWS procedure out there that controls the weld process such that this doesn't happen?
2. Is the procedure such that it depends on the weld size, flange thickness, weld process, etc.?
3. Does it matter if the flange is in compression vs. tension in terms of the danger?




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[WARose]

1. Is there a specification or AWS procedure out there that controls the weld process such that this doesn't happen?

Not that I am aware of.....probably something they don't want to touch for liability purposes anyway.

2. Is the procedure such that it depends on the weld size, flange thickness, weld process, etc.?

I don't know about any AWS procedure......but a good article on this (that takes into account heat input by weld procedure, temperature vs. strength, tension vs. compression, etc.) is:

'Repair Welding Under Load', by: Haensch & Augustyn, published in: "Welding in the World", Vol. 28, No. 9/10, pp. 174-182, 1990.

You can come out of it with all sorts of approaches.....but typically what I have done (for design purposes, after studying the temperature contours in the article) is disregard the flange (and about 5" of the web) during welding for my strength check (if feasible). If that doesn't work, I start adjusting strength parameters based on reduced yield values.

I also direct them in the drawings (if they are welding across both flanges) to allow the first weld to cool before proceeding with the next one.

 

[SlideRuleEra]

AISC "Modern Steel Construction" magazine, May 2015

The link in the article above does not work, but the video is on AISC's YouTube page.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[ldeem]

I have used the procedure described in the AISC webinar few times.

Does anyone have a copy of the Welding in the World reference? I can not find it on line and would like to see an example of calculating the heat input versus temperature curves.

Blodgett also covers this topic in section 7.6

 

[WARose]

Does anyone have a copy of the Welding in the World reference? I can not find it on line and would like to see an example of calculating the heat input versus temperature curves.

I'd post it.....but I'm pretty sure I agreed to observe the copyright when I bought it. It has a pretty useful nomogram that reduces the cross sectional area based on heat input, cross sectional shape, velocity of weld, etc.

One thing about the temperature contours shown in some figures that I noted was: they tended to top out at about 1500^o C near the point of the weld. (And this was for a regular weld.) I always thought welding temps came in much higher than that. But is that for a area right at the tip of the stick? (Question for anyone interested or who knows.)

 

[ldeem]

I would be happy to pay for it if I could find it - do you recall where you purchased it?

 

[WARose]

...do you recall where you purchased it?

Not at this point. It might have been the International Institute of Welding.

 

[ldeem]

I sent them an email - if I get a copy that can be distributed I will post it here.

 

[ldeem]

This reference Repair Welding Under Load', by: Haensch & Augustyn, published in: "Welding in the World", Vol. 28, No. 9/10, pp. 174-182, 1990. is available for 25 euors from

http://www.iiwelding.org

 

[charliealphabravo]

I've never had to write a procedure for this situation so this may be from left field but pulse MIG welders are getting to be more common. They have a much lower heat input since the electrode never touches the puddle.