Nominals for steel plates 2

[mariolucas75]

Dear forum,

Is there a chart / schedule like a pipe schedule for pipes (dia and wall thickness) for dimensions for the steel plates while manufacturing.

Another questions - normally general arrangement drawings for pressure vessels show nominal thickness i guess right?
However nominal thickness is thickness available from a vendor... and my design thickness (which is required thickness + Corr allowance) might be a little bit less right ? So i am looking for chart / weight / schedule for plates that pressure vessel are manufactured from like we have a pipe schedule for pipes with its manufacturer mill tolerances...

Thank you very much

 

[SnTMan]

Tolerances are in the plate specs. SA-20, SA-516, SA-240, etc. etc.

Plate thicknesses are generally available in 1/8" increments, up to, say 1 1/2" 1/4" over that. But not always. Check with your suppliers for avaiability.

... and my design thickness (which is required thickness + Corr allowance) might be a little bit less right ?

Well, you'd hope so

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[JStephen]

Check with local fabricators or plate/material vendors. Some vendors will publish stock lists online.
Tell us what part of the world, and that will narrow it down some.
Very large quantities- check with a mill.

Here locally, for example- 0.1875", 0.25", 0.3125", 0.375", 0.4375" (sometimes), 0.5", 0.5625" (sometimes), 0.625", 0.75", etc. Widths- 72", 96", 120". Lengths 240", 360", 480". Materials SA 36, SA 516-70. Not every combination of length/width/thickness/grade is available, though, so it takes some checking.
I would expect a similar variety (but completely different details) elsewhere in the world.

 

[SnTMan]

A knowledgeable buyer in your org can be a big help also.

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[racookpe1978]

You need to continue to find the answer to several equally important, if not more important questions:
Yes, "What is my minimum calculated thickness, with the correct corrosion allowance and Safety Factor for your company and your application/industry, at the minimum commercial margin?
Yes, "What is available commercially that is greater then that minimum calculated thickness?"

But there are more things to consider:
- What is the maximum thickness, maximum length, maximum width that can be rolled at EACH DIFFERENT fabricator shop?
- What thicknesses need to be special ordered (weeks or months of delay possible in today's world!) and what are available for fabrication immediately?
- What is the cost and supply implication if the vessel is one-of-a-kind, or a routine series of the same pressure vessels (4 each month needed for the next 36 months), or many copies of the same PV but only one order one-time (200 PV's needed in 3 weeks)? That will affect how the material ordered from the mill.
- What is the maximum (and minimum!) weight and shape that can be handled at each shop? A 1/4 thick walled vessel 12 ft long by 16 feet dia will need more support structure and bracing before and after each lift than the rolled steel itself will weigh.
- How will each PV be assembled, how many separate plates will be needed and what are the weld/rivet QA certs needed?