Plate Thickness 1

[arvindpandit]

hi...

can anybody solve my problem?
There is a vessel (bullet) having the minimum required thickness (or we can say calculated) is 37.483 mm after adding CA as per ASME code formula. I have mentioned in my MDS shell thickness min 38 mm thk. Now vessel has been ordered to vendor and he is offering same thickness of 38 mm and going to procure 38 mm plate. We are asking vendor to add other tolerance like rolling tolerance fabrication tolerance etc. and consider min 40mm thk and procure accordingly. but vendor is keep saying it is as per our MDS and he checked that it is ok.
So please help me bcoz my senior and higher personal are not going to accept 38 mm thickness. How can i escape and make vendor to agree with 40 mm.

Also, vendor has offered the bid stage 40 mm min thk. Now he is saying that was tentative only.

Thanks in advance.

 

[EdStainless]

Your paperwork states 38mm minimum wall correct?
Then he can't order 38mm average thickness plate and make it meet spec.
If he buys plate that is 38mm min (all tol to the plus side) then he will be OK, and you should be fine.
As long as he realizes that when you do UT wall thickness measurements that you will reject it if you find any location thinner than 38.0mm.

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P.E. Metallurgy, Plymouth Tube

 

[Compositepro]

Arvindpandit, this forum is for engineering professionals, so please use correct grammar and spelling.

 

[KernOily]

I dunno, I kinda like 'bcoz'. This way, a guy can never get his texting and his perfeshunal communicashuns mixed up. You can just use one language for everything. <retch>

Being a non-native English speaker is one thing. Crappy/lazy spelling and grammar is something else entirely. <rant mode off>

 

[jte]

Arvind-

Well, along with Compositepro and KernOily, I will say that a professional post would get you a bit more respect. For example, in addition to poor presentation you are also being lazy in failing to tell us which code - specifically - you are using for your design. Great, you are using one of the ASME codes. I can think of at least five ASME codes which you might be using. But it would take too long for you to key in the few letters to let us know which one...

If you are using one of the most common ASME code for vessels, that would be ASME Section VIII Div. 1, then you cannot use the Code to force your fabricator to make you look good. Your concern for tolerances is noted, but have you ever been involved with procuring a vessel made of rolled plate before? Are you perhaps expecting the shell to be 12.5% under the specified thickness? Have you read the code yourself? If VIII-1 then get a copy and read UG-16(c). You'll discover that plate used in VIII-1 construction can be less than specified or nominal thickness - within limits - and still be fully compliant with the Code. Then write a nice note to your fabricator apologizing for your lack of understanding and your attempt to make him look bad instead of accepting a bit of personal responsibility.

Finally, this query would reach a more targeted audience at forum794. But don't double post. You've already started this thread here and it has generated a few replies, so don't re-post the same issue in another forum. Just remember it for next time.