Weld size of butt welds
Weld size of butt welds
(OP)
Is there a limit on size of weld for butt welded joints at 90 degrees. Specifically I want to join a 1" plate at 90 degrees to a 1/4" plate with a fillet weld on one side. Is 1/4" weld acceptable?





RE: Weld size of butt welds
RE: Weld size of butt welds
Ciao.
RE: Weld size of butt welds
Smaller size welds are not very effective, and I would not recommend it. If you look at most Codes and Standards and the book Design of Weldments by Blodgett, 3/16” - 1/4" fillets are about it for 1/4" plate thickness. Anything smaller is a tack weld, and I wouldn't depend on this for load-carrying capability.
RE: Weld size of butt welds
There are specific requirements for non-low hydrogen that is outside the note below.
D1.1 Table 2.2
1/8" single pass Fillet Welds are acceptable for metals where the thickness is less than or equal to 1/4"
(note: the minimum size for dynamically loaded structures is 3/16in. - 5mm.) If these are sufficient to satisfy design requirements.
There are lots of variables like pre-qualified joints etc.
RE: Weld size of butt welds
Check the links in this post.
RE: Weld size of butt welds
Minimum: 1/8"
Maximum: 3/16"
RE: Weld size of butt welds
Can you cite the reference that states max fillet weld size is 3/16"? The reason I ask is that the codes and standards I am familar with have no problem with a full fillet weld size of 1/4" for this type of tee joint.
Steve Braune
Tank Industry Consultants
www.tankindustry.com
RE: Weld size of butt welds
From my old "Steel Structures Design & Behavior" Salmon & Johnson, "fillet weld sizes are governed by the thicker of the two pieces being joined, except the weld size need not exceed the thickness of the thinner piece joined unless a larger size is required by calculated stress.
It is my understanding that the thicker plate draws heat away from the joint so a larger fillet is required to avoid incomplete fussion.
If the use of an 1/8 fillet to join a 1/4" plate to a 1" plate is now allowed, I have a lot of applicatons where I could save on welding costs.
RE: Weld size of butt welds
Hg
Eng-Tips policies: FAQ731-376
RE: Weld size of butt welds
1 item to consider when joining 2 extremely different thicknesses of metals is preheat to minimize stress cracking etc. due to the larger metal robbing the heat input.
RE: Weld size of butt welds
I have a small understanding of welding procedures, but I don't get involved in specifying welding procedures.
In my work I just specify the type of weld. 98% of the welds I specify are fillet welds 3/8" and less. All my company's welding is done by other vendors.
In most case I work with even the minimum weld size allowed provideds more then the enough strength. I design mostly steel used in wood connectons, so the weak element is normally the wood.
With all the responses to the intial question I am still confused. Some of the responses seem to indicate that I could welded a 1/2 plate perpendicular to a 1" plate with a 1/8" if the 1/8" fillet had sufficient strength.
RE: Weld size of butt welds
Putting Human Factor Back in Engineering
RE: Weld size of butt welds
I am not familiar with the ASME VIII code so I rely on the AISC Manual.
In the applications I deal with the weld size is more dependent on the minimum size required than on strength. The weld configurations I deal with are also governed by company policy.
For example if I was welding up a base shoe that had a 12" x 12", 3/4" thick base plate with two 12" x 8", 3/" thick vertical side plates space 9" apart. I would call for a 3/8" fillet on the outside of the two vertical plates, which based on my understanding would be the minimum fillet allowed by the AISC code. Then following company policy I would use a 3/8" fillet on the inside. A "T" joint with two 3/8" fillets.
In a typical application the uplift on the vertical plates would be around 11 kips per plate.
There are a lot of times in the application above where I would like to call for a 1/8" fillet on the inside. Now I could just treat the inside weld as a tack weld and not depend on it for strength. However there are times when I would like to be able to assign a load value to it or even use 1/4" on the outside with 1/8" on the inside.
Now you might wonder why I need a 3/4" thick base plate. The problem I run into is that sometimes the EOR will specify minimum plate thickness. So where I could use a 3/8" plate, I may be required by the EOR to use 3/4" plate.
RE: Weld size of butt welds
You mention that you depend or rely on AISC for design.
I'm fairly sure that AISC refers to AWS D1.1 for materials starting at 1/8" minimum.
AWS is where I got the information above about usiing 1/8" single pass Fillet Welds being acceptable for metals where the thickness is less than or equal to 1/4"
You should try to get the latest edition of AWS D1.1 for reference.
RE: Weld size of butt welds
I will try to borrow the latest edition of AWS D1.1 from one of our consultants.