Calculate Weld Strength of Fillet Weld

[shoehorn6]

Right I have been thrown in at the deep end with weld calcs. Previously I have never dealt with them so could do with some help.
I am trying to calculate if my fillet weld is going to be strong enough.
I have a circular 6mm plate, diameter =144mm that is going to be weld inside a pipe. It will be welded at 3 tabs each 10mm in length.
At present I am using a 4mm double sided fillet weld and need to check if this will be strong enough.
There will be pressure of 5.4bar in the pipe.
The length of pipe is 200mm
Let me know if you need anything else.
Your help would be greatly appreciated.

Cheers

 

[Ron]

Is this a block-off plate or an orifice restrictor plate? Why only a partial circumferential weld? What is the material? Have you considered corrosion in your weld design?

 

[shoehorn6]

Its a baffle plate. Liquid will flow down between gaps around the edge and it will be weld at the 3 tabs. I don't have any flexibility in terms of actually design just need to confirm if the double 4mm fillet weld at each tab will be strong enough.

The material is SS NAG 18/10L

Shoe

 

[kingnero]

Is 4 mm the "a" or the "z" length (the leg length or the throat)?

And is there a pressure differential of 5.4 bar over the baffle plate itself? Or the total pressure in your system?

I don't quite understand the setup, will the round plate you'll weld in the pipe, be perforated or are there large gaps towards the pipe wall, so the fluid can pass easily?

Does the length of the pipe (200 mm) comes into play for the calcs? As there must be a tank or valve or something attached at least to one end I'd say...

 

[shoehorn6]

Ok so the 4mm I think is the leg length

The 5.4 bar is total pressure in the system.

The total length is actually 400mm with a nozzle at either end the baffle plate is in the middle.

There will be a gap between the round plate (baffle) and the pipe of 6mm except for the 3 weld tabs.

 

[kingnero]

If the total pressure is the same on both sides of the baffle, in theory you wouldn't even need welds.

Before starting the calcs, you do need to have an idea of the force that will be exerted by the fluid on the baffle plate! We really can't do that from here...

 

[shoehorn6]

Sorry got that wrong there will be a pressure difference across the baffle of 5.4bar.

 

[desertfox]

http://www.roymech.co.uk/Useful_Tables/Form/Weld_strength.html

desertfox

 

[nuche1973]

Take a look at ASME Section VIII Division 1, Subsection B, Part UW.

"I drank what?!" Socrates?

 

[JStephen]

Be aware that the ASME Code, the AWS Structural Welding Code, etc. will differ considerably in the allowable weld strength and also how weld strength is figured. So first step is to figure out what code, if any, is applicable to the weld.