Maximum Allowable reduction in Sheet Thickness

[m.wasif]

Hello,
I am fabricating heat Exhanger through one of local contractor. As per drawing specification the thickness of Tube sheet is 30mm . However the available plate for tube sheet have thickness of 63mm. Please confirm that is it allowable to reduce thickness by 33mm through machining. Does this thickness reduction will effect on material integrity. Also please confirm through relevant ASME or TEMA standard that allows or quote any clause related to thickness reduction through machining.

Plate material: Carbon Steel

Regards,
Wasif

 

[EdStainless]

If I was going to remove 45% of the thickness I would start by take a few tensile bars at various depths.
What if the properties are very non-uniform?
There is no prohibition against this (after all people cut 1x4 bar from 4" thick plate all of the time).
But there is a real chance of ending up with different properties than you expect.

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P.E. Metallurgy, Plymouth Tube

 

[chicopee]

Run the calculations using the ASME code (VIII) on unfired pressure vessel to determine if the 30mm thickness is adequate.