holding time is 1hr x 3cycles (vessel thk considered as 25mm). Then
the test specimen should have the PWHT holding time between 2.4 hrs
(minimum) & 3.6 hrs (maximum) heat treated. ( 1hr x 3cycles x0.8= 2.4
hrs) & (1hr x 3cycles x1.2= 3.6 hrs).
But one think I do not understand .... vessel portion exposed to the
maximum vessel-portion temperature. (condition A)
.....vessel portion exposed to the minimum vessel-portion temperature.
(condition B) If the vessel soaking temp is 690+/-15 deg C then what
is meant by minimum vessel portion temperature & maximum vessel
portion temperature?
Thanks and Regards,
M.A.Mujeeb Ali
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
On Mar 15, 11:15 am, "sachin sankhe" <sachin.san...@rediffmail.com>
wrote:
> Note: Forwarded message attached
>
>
>
> -- Original Message --
>
> From: "sachin sankhe"sachin.san...@rediffmail.com
> To: sujeetsan...@gmail.com
> Subject: Re: Re: [MW:4557] Test Specimen Heat Treatment
>
>
>
>
>
> [ Attached Message ]From:"sachin sankhe"<sachin.san...@rediffmail.com>To:<sujeetsan...@gmail.com>Date:Subject:Re: Re: [MW:4557] Test Specimen Heat Treatment
>
> Hi,
> This clause is pertaining to all thermal treatment of material during fab stage exceeding 480 deg.C.This temp is not related to process temp of process fluid in vessel during operating condition
> Refer ASME sec VIII Div.1 UCS-85 B and 85 c.
> Clause which you are referring is Mandatory for specific grade of Low alloy steel as per ASMESec VIII Div 1 Mandatory Appendix 31
> As an example lets say as for certain grade of LAS PWHT temp is 690 Deg. C ,then for test specimen(25 mm) temp can be 690-15=675 deg.c.
> Holding time may be 80 % of total time that vessel is going to see in its entire life cycle.i.e
>
> Vessel in its entire life cycle may be subjected to undermentioned cycle
> 1.Actual PWHT CYCLE(Holding time 1 hr for 25 mm thk)
> 2.PWHT for shop repair carried out after actual PWHT of entire equipment(Holding time 1 hr for 25 mm thk)
> 3.Site Repair(Holding time 1 hr for 25 mm thk)
> 4.One additional cylce of PWHT for any future requirement(Holding time 1 hr for 25 mm thk)
>
> So in all test specimen is to be subjetced to 4 cycle i.e Holding time 4 * 0.85=3.4 hrs
> So same aspect may be extended to other clause with 120% holding time
>
> Regards
> Sachin
>
> On Sat, 13 Mar 2010 22:27:52 +0530 >Hi ,
> Â
> It stated you should hold the Speciment minimum at 80 % of the Maximum Vessel Portion Temp For condition A Â ( This information you will get from the Data sheet which give the max exposure of the vessel ) i.e if the Max Vessel Temp is 100 Dec C you should hold the specimen minimum at 80 Degree C and the range can be ( 80 to 100 Degree C )
>
> Â
> Same for the minimum Temp , the holding Temp for condition B should be minimum 120 % of the Minimum Vessel Temp . i.e if the Minimum Temp is - 40 you should hold at - 48 Deg and the range will be ( - 40 to - 48 Deg C )
>
> Â
> Thanks
> Â
> Sujeet
>
> On Mon, Mar 8, 2010 at 12:19 PM, qaqcmpm wrote:
>
> 3.4.3 Test Specimen Heat Treatment
> 3.4.3.1 Two sets of tension specimens and one set of Charpy impact
>
> specimens shall be tested. One set each of the tension specimens shall
> be exposed to heat treatment condition A. The second set of tension
> specimens and the set of Charpy specimens shall be exposed to heat
> treatment Condition B.
>
> a) Condition A â€" ....... Time at temperature shall be no less than 80%
> of the actual holding time of the vessel portion exposed to the
> maximum vessel-portion temperature.
> b) Condition B â€" ....... Time at temperature shall be no more than
>
> 120% of the actual hold time of the vessel portion exposed to the
> minimum vessel-portion temperature
>
> Can anybody explain this 80% & 120% with simple example?
>
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