fillet weld sizes

[marmon]

what is a full strength weld? i have a dwg which this is required, the term seems pretty vaugue to me. I took it as being a full weld (not stitched). anyways does someone have a rule of thumb or table that has fillet weld sizes for different size plates?? im in canada so if possible to CWB standards

 

[corus]

Generally no bigger than the plate thickness but otherwise whatever size you want.

corus

 

[Scorch]

Give this website a try you should be able to find your answer there.

http://www.engineersedge.com/weld_design_menu.shtml

Don't worry about people stealing your ideas. If your ideas are any good, you'll have to ram them down people's throats.
--Howard Aiken, IBM engineer

 

[Goahead]

AWS Publication
FWSH Design Handbook for Calculating Fillet Weld Sizes
might give you what you look for.
Please note that fillet welds should be designed for stress in shear along the fillet, avoiding a moment developing across a one sided fillet weld.
Depending on the design, the requirement might also mean full penetration weld, with beveling of the transverse element (obviously depending on thickness) before welding the fillet on the whole thickness section.

http://www.welding-advisers.com/

 

[metengr]

First, you must define what is meant by "full strength" for your specific design application - shear and/or tensile loads. Fillet welds exhibit lower fatigue strength, and are highly dependent on load direction with respect to the weld axis, in comparison to full penetration butt welds.

 

[marmon]

these (brackets have misc plates in all directions all welds will be @ in 90 degree corners

 

[JStephen]

The "full strength" term is vague, check with whoever wrote it to see what they want.

As I recall, the AWS Structural Welding Code prohibits fillet welds that are as thick as the plate. Meanwhile, the tank codes require fillet welds that are as thick as the plate. The correct weld would be dependent upon the design code used, and need to come from whoever designed it.

"Full Strength" is not included in the AWS "Standard Welding Terms and Definitions".

 

[corus]

Full strength probably refers to a full penetration weld. That has the same strength as the plate thickness. I'd get that standard so named which will probably advise you on the welding procedure.

corus

 

[Cockroach]

Corus is correct. Full strength means full penetration of the weld and implies that weld performance does not compromise the plate at the joint.

The only thing that differs in Canada over our American counterparts is the quality of weld technician. This becomes apparent with testing, certification of welds and weld procedure approvals. Your local provincial Boiler Branch governs legislation of weld application, I strongly suggest you contact them for direction.

Also, a nice rule of thumb for weld sizes, measured at the throat of the weld, is not to exceed 75% plate thickness.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[JStephen]

Note that even when you have a full penetration weld, the assumed joint efficiency still varies depending on the code used. Under ASME, you'd have to do 100% radiograph to consider it a "full strength" weld.

Once again, I encourage you to contact whoever did that drawing and find out what they want. If it's not obvious from the drawing whether it's a lap joint or butt weld, or what, the drawing is the problem, not your interpretation.

 

[flamby]

"Full strength weld" only tells you that full capacity of plate becomes available. It doesn't tell you whether it is a butt of fillet weld. I do not consider it synonym of "full penetration weld" which is a butt weld.

As JStephen said, these words are not defined and may mean different things to different people. It is good to ask the place where these were drafted.

To me, a full strength fillet weld is about 71% of plate thickness fillet weld, on both sides. But, there are caveats as always.

Ciao.

 

[marmon]

71ish% when two plates are 90 degrees to eachother, or overlapped?

 

[flamby]

90 degree!

Ciao.