Re: [MW:6171] PWHT above Tempering Temperature

For higher-strength normalized and tempered materials, there is consequently a possibility of reducing tensile properties of the base material, particularly if long holding times at the higher temperatures are used. there is cautionary statement in B31.3 for P4/5 material in appendix F.

API 582 states  "For Q&T or N&T materials, the PWHT holding temperature shall be at least 25F below the original temperaing temperature of the base metal".

many licensor specifications (for e.g UOP it is 28 °C)  states between 20 - 30 °C.

On Wed, Jul 28, 2010 at 7:29 PM, limesh M <limesh78@gmail.com> wrote:

Dear All,

Is there any clause in ASME BPV  which ban performing PWHT above
material's tempering temperature?


Apart from ASME BPV, any other code restrict PWHT above tempering
temperature?


What would happen if we do PWHT above material's tempering
temperature?


What would be the maximum acceptable close range variations(For
example-50 to 100 Degree Celcius above tempering temp.) above
tempering temperature during PWHT?


Thanks and Regards,


Limesh

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