Re: [MW:6275] PWHT above Tempering Temperature

Dear All,

 

Thank you everybody for your valuable inputs.

 

I have reviewed B31.3 2008 edition and found that "Heat treatment temperature listed in 331.1.1 for some P No. 4 and P.No. 5 materials may be higher than the minimum tempering temperature specified in the ASTM specifications for the base material. For higher strength normalised and tempered materials,there is consequently a possibility of reducing tensile properties of the base materials,particularly if long holding times at the higher temperatures are used".

 

I think this is only a cautionary notice.In PWHT operation I am not crossing the lower critical temperature of steel during holding time.

is there any problem?

 

For eg.Construction code ASME B31.3, Material ASTM A 335 P11, 650 Degree C was the material tempering temperature,unfortunately PWHT completed with a holding point of  730 Degree C.Will it create a big problem?

 

Thanks and Regards,

 

 

Limesh

On Wed, Jul 28, 2010 at 11:36 PM, <george.dilintas@gr.bureauveritas.com> wrote:

In any case you have to stay below the lower transformation temperature

----- Original Message -----
From: limesh M [limesh78@gmail.com]
Sent: 28/07/2010 06:59 MST
To: "Materials & Welding" <materials-welding@googlegroups.com>
Subject: [MW:6170] PWHT above Tempering Temperature



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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