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Up Topic American Welding Society Services / Technical Standards & Publications / Max Fillet Leg Size
- - By welderla (*) Date 09-20-2010 02:58
What is the maximum fillet leg size allowable in D1.1;2000?  I found a note in the commentary that said it's ok as long as it doesn't infer with the end use of the member (C-15.3).  But is there any other reference to oversized welds?  If the drawing calls out for a 3/8" fillet weld and the spec calls out for D1.1:2000 then how large it too large?
Parent - - By waccobird (****) Date 09-20-2010 09:17
welderla
The correct answer is any larger than the engineer specifies is too large.
There are all kinds of scenarios. But the same answer.
When a weld is called for the estimators take that into consideration for their bid and if the person in the shop applies more weld than specified then the welder is cutting into Profit.
In some cases an over-sized weld in a structure can actually be detrimental by causing a stress riser.
Over 40 years I have been welding and I have learned that a welder isn't a welder if they cannot consistently produce the welds specified on the drawings.
Welding is not just a hand and eye coordination thing.
Just my observations and ΒΆΒΆ's.
Good Luck
Marshall
Parent - - By swnorris (****) Date 09-20-2010 17:03
D1.1 2000 limits the maximum fillet weld size at Figure 2.1, stating "details for prequalified fillet welds".  For the exact same Figure 2.1 in the current 2010 code, it specifically states that it's the "maximum fillet weld size along edges in lap joints".  I think this detail was intended for lap joints, period.

I also agree with everything Marshall has said.
Parent - - By 803056 (*****) Date 09-20-2010 18:37
The inquiry was specific to whether D1.1 limited the maximum size of the fillet weld. As noted SWN, the only size restriction is for the fillet weld along the edge of a lap joint and even that is for the purpose of design, not fabrication or inspection. As long as the position/location of the original edge can be established, the weld can be "oversized" and it is not prohibited by AWS D1.1. 

The issue of whether the weld is too large is one of workmanship. It is not addressed by D1.1 (remember, the commentary is not part of the code requirements). As long as the fillet weld is not undersized, the profile is acceptable, and the visual acceptance criteria of Table 6.1 are met, the requirements of D1.1 are satisfied.

Best regards - Al
Parent - By Milton Gravitt (***) Date 09-20-2010 19:17
Most prints that I have seen all weld size are minimum. 

    M.G.
Parent - - By Duke (***) Date 09-21-2010 02:23
Marshall said "In some cases an over-sized weld in a structure can actually be detrimental by causing a stress riser."
no kidding...
Take a look at this report.. note that welds joining 1/4" pole section to 1 1/2" baseplates are 3/4" fillet welds:
Now why in the hell do you need a 3/4" fillet weld on 1/4" material???
http://alt.coxnewsweb.com/statesman/pdf/04/2009_0412_pole.pdf
Parent - By waccobird (****) Date 09-21-2010 08:42
Dan
That was a good example for the O.P. to use.
Thank You for the Document.
Marshall
Parent - By MBSims (****) Date 09-22-2010 01:10
A good report and good reading.  I noticed the postulated cause of the failure was the use of a fillet weld instead of a full penetration weld.  It was not suggested that an oversize fillet was the cause.  A fillet weld geometry has a higher stress intensification factor (SIF) than a full penetration groove weld, which is probably why the FEA showed a load of 5,000 psi instead of the calculated allowable of 2,500 psi.  The SIF does not change with fillet size, it is a function of geometric shape.
Up Topic American Welding Society Services / Technical Standards & Publications / Max Fillet Leg Size

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