Re: [MW:12083] PWHT near to Tempering temperature for SA350 LF2 CL 1 Flanges

as long as PWHT temperature is lower than tempering temperature. there
will be no effect on mech properties.
since you are deviating from the contractual requirement, you need to
approach UOP with a specific deviation request. i have seen in the
past UOP approved such requests. you can even demonstrate by a
simulated test coupon. FYI, API recommends 15 °C difference (refer
Table 5 note a of API RP 582)

On Wed, Aug 3, 2011 at 2:57 PM, asad azmi <azmiasadayub@gmail.com> wrote:
> Dear All,
>
> Greetings.
>
> As per  UOP # 3-12-5 para 4.1.i.
> The tempering temperature for tempered material shall be at least 50 ºF (28
> ºC)
> greater than the maximum intermediate or postweld heat treatment
> temperature.
>
> Consttuction code - ASME SEC VIII DIV 1, Flanges are SS 316L overlaid in ID
> and Gasket face.
>
> During review of MTC for SA 350 LF2 CL 1, Flanges Tempering Temperature
> observed  greater by  10  deg celcius from PWHT Temperature.
>
> Details are as bleow --
>
> Flanges are supplied in Quenched and Tempered condition. Tempering
> temperature is 630 deg celcius.
>
> PWHT temperature for the vessel is  620 deg celcius( minimum).
>
> Please suggest whtether this can be accepted.
>
> Thanks & Regards
>
> Asad Azmi
>

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