Finding the weld size

Date 08-11-2014 15:32

I struggle with finding the correct weld size for a joint. Is there any Standard for the same ?
I am reviewing a drawing where designer has asked me to do a fillet weld of size 0.18 inch on a 0.12 inch thick pipe with 0.25 inch plate. I think it will burn the pipe?
Thoughts?

By pipewelder_1999 (****)

Date 08-11-2014 16:36

Seems normal to me. If the weld sizes are specified by legs, then thats in the ball park. If specified by min throat it seems a bit much but still fine. The designer was the designer so I would check with him/her 1st.

If you are working with something that is sensitive to some overwelding you may need some face to face type help.

By Harman

Date 08-11-2014 18:01

Shouldn't my weld - leg size be smaller than thickness of the thinner material ?

By pipewelder_1999 (****)

Date 08-11-2014 18:13

An equal leg fillet weld will normally have a theoretical throat .707*Leg Size .

However that is something designers decide. Not all welds are designed to be or need to be "Full Strength".

In some countries, the fillet weld size is referring to the throat. That is NOT the case with AWS Welding Symbols.

Hope this helps

Gerald

By jwright650 (*****)

Date 08-11-2014 17:37

another thought....sometimes a welding code will spell out a minimum fillet weld size....ie. AWS D1.1:2010 calls out a 3/16 fillet as the smallest fillet weld size to be used on structural steel and sometimes the engineer of record will still call for weld sizes smaller than that. Like Gerald said, unless the material is sensitive to overwelding, it is permissible to have an oversize fillet weld as long as the extra weld material doesn't get in the way of something.

By 803056

Date 08-11-2014 18:48

The weld size specified by the drawing produces a throat dimension that is equivalent to the wall thickness of the pipe that is welded to the plate.

Depending on the design standard being used, it may be the weld size required to produce a "full" strength fillet weld. The design standard typically limits the stress on the weld as well as the base metal. AISC / AWS limits the stress on the base metal to 0.4 times the yield strength of the base metal for shear and 0.6 times the yield strength of the base metal for tensile stress. The allowable stress on the weld is 0.3 times the tensile strength of the filler metal. It balances so that the weld and the base metal are equally stressed at full design load.

Best regards - Al