Help With A Weld Size Calculation 5

[iam42]

Can anyone show me how to calculate the weld size required on the attached sketch.

Any help or direction would be greatly appreciated.

Thank You

IAM

 

[metengr]

See below for some guidance for weld calcs;

http://www.gowelding.com/calcs/

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

Make sure you understand the forces acting on the fillet weld - shear, tensile and treat the fillet weld throat(s) as a line in the circumferential direction to carry the load. Once you have evaluated the forces, you can use the above web sites for the appropiate formula(s).

 

[unclesyd]

iam42,

I believe that you are building a bomb based on the dimensions given in your sketch.

Can you come back with a little more information on what you are attempting?

 

[iam42]

unclesyd,

What is so unusual about the dimensions?

It is for a simple pressure test.

IAM

 

[unclesyd]

At your pressure there is nothing simple about pressure testing.

My first impression was the there is a disparity in the two flanges. The fixed flange is less than 1/2 the removable flange. Normally flanges fixed and removable are the same thickness to prevent rotation when pressure is applied.
The pressures you are talking about will require at least a Class 600 or more than likely a Class 900 ASME flange.


Can you comeback with the purpose of your test?

 

[iam42]

Unclesyd,

My question is theoritical. I am not actually testing anything. The purpose of the sketch was to show a basic layout.

I am looking for the required equations to calculate weld size.

IAM

 

[unclesyd]

Please keep this exercise theoretical.

Aside from the references from metengr you are into
into the strength of weldments here is an excellent book that is well worth the price of $15.00.

"Design of Weldments by Omer Blodgett"

https://ssl.lincolnelectric.com/lincoln/apdirect/item.asp?prodnum=DW

 

[desertfox]

Hi iam42

This site might help:-

http://www.mech.uwa.edu.au/DANotes/welds/traditional/traditional.html

desertfox

 

[desertfox]

Hi iam42

This seems to represent your configuration, stress the weld for bending and shear:-

http://www.gowelding.com/calcs/c4.html

regards

desertfox

 

[arto]

This should be designed & build by an ASME Code stampholder, or whatever agency has jurisdiction for your location.

 

[MJCronin]

iam42....

I agree with unclesyd and the the "bomb" comments he posted above..

Cmon,....Is this a homework problem of some type ?

Why is there no gasket on the "metal to metal" joint ?

Is the media a gas or liquid ?

Why not use a "slip-on" or "weld-neck" flange for this type of piping joint ? The weld size and pressure ratings are pre-qualified..

My opinion only...

-MJC

 

[iam42]

MJCronin,

All I am looking for is some constructive help with weld size calculation. I am not asking you to redesign my "sketch".

If you can help me with the calc that would be great.

IAM

 

[prex]

Well iam42, this appears to be a temporary cover for hydrotesting, so the worries of others above are perhaps a bit excessive.
However I concur with the others in that your assembly has something unusual: before questioning about the weld size you should be sure that the ring flange is correct (and I doubt about it).
Supposing you don't want the pipe to cooperate with the flange in resisting bolt moments (otherwise you would be started for a FEM analysis, as there are no formulae for that in the code), the weld has to resist shear only and the load is the same you use to design the flange. Hence the calculation of that weld is straightforward, at least for someone that professionally needs to insure the safety of a real thing of that sort. By the way your weld is equivalent to that of a slip on flange, and the code prescribes its minimum dimension.

prex

http://www.xcalcs.com

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