Thursday, July 12, 2012

Re: [MW:14857] Heating/cooling rate requirement for PWHT

The cooling rate could be anything beyond 50 deg.C. but within 222 Deg. C.
Hence, it is not required to reheat the joint.

sridhar.
 
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Dear All,

As per ASME section Ⅲ NX-4623,Above 800°F(425℃) the rate of heating and
cooling in any hourly interval shall not exceed 400°F(222℃)divided by the
maximum thickness in inches of the material being heat treated,but shall
not exceed 400°F(222℃)and *need not to be less than 100**°F(56**℃)in an
hourly interval.*



Now the actual heating and cooling rate in our production we made is 50℃/hour
which is less than 56℃/hour required above. Our custom insist that this is
unacceptable and should be reheated. But my understanding is that the *56**℃is not a mandatory requirement
*and only the upper limitation is required. Do I understand this correctly?
PLZ guide me! Appreciate it!

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[MW:34820] RE: 34813] Clarification in Rate of heating and cooling.

Hello,   Please see the response below.   Regards.   P. Goswami, P. Eng, IWE.   From: materials-welding@googlegroups.com <materials-weld...