khodabandeh; with all due respect, having read and responded to your other postings, it sounds like you have no control over your contractor.
As a Representative of the Owner, YOU must either gain that control, forcing your contractor to comply with codes and specifications or hire someone who will. Personally, if I were your manager, based on the other issues I've read, you would be terminated.
I'm sorry to sound so harsh, but it seems to me that you are using this Forum as a board to cry over your own faults, seeking some "magic" solution! The solution is simple; get contol of YOUR project!
Khodabandeh,
I'm also an engineer from a third world, underdeveloped country and I understand how you feel. You and me know that in third world, underdeveloped countries things are not as easy as, and do not work as well as they do in first world, superdeveloped ones.
One example among hundreds is the difficulty in getting the last edition of any Code or standard, which I mentioned in another posting and was not entirely understood by the other frequentors of this Forum. None of their fault, they just aren't accostumed to the hard times we are used to have.
So, I decided to give you a third world, underdeveloped hand to help you getting off the mess you're into.
It's a well known fact that residual stresses in metals increase their hardness. It's also a well known fact that an increase in hardness decreases the corrosion resistance of a metal.
This is not of a great concern in ASME/ANSI B31.1 Code for Power Piping, because in a power station there aren't highly corrosive services, but it's of a great concern in B31.3 Code for Chemical Plant Piping, because in chemical plants THERE ARE highly corrosive services.
So, B31.1 says nothing, but B31.3 requires that after stress relief the hardness of the weld metal and HAZ be lower that a certain value, usually 210 BHN (Brinell). Nowadays residual stresses can be measured by means of a portable x-ray difractometer, but when that Code was first written this equipment didn't exist and the only way to have an idea of the residual stress was by ANALOGY with hardness. The higher the hardness the higher the stress, and viceversa.
So far, the Code says nothing on x-ray difractometry and keeps on speaking of Brinell hardness.
So, what your contractor is trying to do is to convice you to make an analogy between ASME VIII and B31.3. The analogy is the following:
"We'll measure the hardness of the vessel weld, and if the hardness is less than 210 BHN we can assume that the residual stresses are below the safety allowable maximum. In this case, we don't need to make the PWHT of the vessel".
My opinion is the following: if the vessel has been designed and constructed according to ASME VIII and this is written in the contract documents, then ASME VIII is the same in first, second and third world countries, as well as in the Moon, Saturn and Jupiter: it must be followed and stop saying nonsenses. When the contractor signed the contract, he of course had read it and should have included in his price all the requirements of the codes and standards that were mentioned in it.
Now, Khodabandeh, I must say that you're trying to use this Forum as a source of free engineering advice, and this isn't fair. If you're having difficulty in understanding the Codes and standards, then you should hire a consultant and be prepared to pay a reasonable fee. A competent consultant will interpreter the applicable standards and will be ready to discuss them with the "difficult to talk with" contractor.
Giovanni S. Crisi
Sao Paulo - Brazil
Khod,
Your post presents no questions. All you are doing is showing your total lack of control and inability to make sound decisions. Sir, with respect, I cannot see how you are still employed. From reading this for the last 3 days, it appears that you are inviting us to your pity party, and I respectfully decline. From reading all the other posts you've left, it appears to me you are totally in the wrong line of work. Your contractor already has you in his scopes; you are not listened to and it doesn't appear that they respect you. At this point you are just wasting all our time with trivial nonsense. Instead of spending all your time in this forum, you need to be spending some time with people that have enough backbone to stand up to this contractor, if it's not too late.
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