RE: [MW:25937] PWHT T-T Cycle Range for WPS with Impact Requirement

It is not a maximum but is a minimum.  As the DBTT increases with increased time at temperature, the concern is that the procedure qualification coupon must see at least 80% of the time at temperature to be used in actual fabrication.  If your qualification was performed with greater time than the minimum, it is assumed that this a worse case scenario than will be experienced in fabrication.  Often, therefore, PQR test plates will be held for extended periods of time to allow for fabrication and a repair cycle or two, greatly exceeding the anticipated fabrication PWHT time.

 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Amit Vishwakarma
Sent: Wednesday, January 18, 2017 9:00 AM
To: Materials & Welding
Subject: Re: [MW:25924] PWHT T-T Cycle Range for WPS with Impact Requirement

 

Dear Experts

 

for e.g, PWHT of 30mm thk is heat treated at 610 degC for 150min then maximum soaking temp would be 150*(100/80) =  187.5min, if supplementary variables are considered

Please correct if I misinterpreted QW-407.2

 

Regards

Amit Vishwakarma

On Tuesday, November 15, 2016 at 4:10:50 PM UTC+5:30, Vivek Pandey wrote:

Dear sir,
if supplementary essential not required,then can we use existing 3 times PWHT cycle PQR for production weld thickness 25mm with SR cycle 1 hour.

1) What will be the effect of soaking time range higher on production weld if same existing 40mm thk PQR used on 25mm production weld with same soaking time as per PQR..

As per QW-407.2 .Soaking time and temp equivalent or at least 80% aggregate of encounter production weld.Soaking time not restricted for exceeding higher side.
please correct me if my interpretation is wrong.

Regards,
Vivek Pandey


On Tuesday, 15 November 2016 09:04:08 UTC+5:30, George Dilintas wrote:

your range in case impact test is a requirement starts from 16 mm and not from 5mm (since your test coupon is 40 mm)

Assuming the test coupon was Pno1 then the mandatory holding time was 1,6 hours and not 3 hours. Since you have used much more time than required you have to requalify your WPS

 

2016-11-14 11:40 GMT+02:00 Bhavesh Patil <bhavesh...@gmail.com>:

Dear Sir,

If we have PQR with PWHT for T-T 610°C & 3 Hrs. for Thickness 40mm as per ASME Sec. IX. for SMAW. Consequently we have WPS for Range of 5 to 200mm Thickness (PQR is tested for Impact at -27°C).

Now the Confusion is can we use same PQR to Prepare WPS for 25mm thick Production weld with T-T 610°C & 1Hrs if supplementary essentials are applicable? Now as per Table QW253 & QW 407.2 the production weld PWHT T-T cycle essentially Equivalent or at least 80%.

QW-407.2 A change in the postweld heat treatment
(see QW-407.1) temperature and time range
The procedure qualification test shall be subjected to
PWHT essentially equivalent to that encountered in the
fabrication of production welds, including at least 80%
of the aggregate times at temperature(s). The PWHT total
time(s) at temperature(s) may be applied in one heating
cycle.

Thanks & Regards,

Bhavesh

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--

Dr. Georgios Dilintas,

Dipl. Ing. In Aeronautic and Space Engineering

Ph.D in Mechanics of Solids - Computational Mechanics

A.I.S, A.N.I, IRCA Lead Auditor

Welding, Stress Analysis, Corrosion, QA/QC, Failure Analysis, Risk Analysis

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