[MW:2633] RE: 2616] Re: QW 407.3

(1)  QW-407.2 is, typically, a supplementary essential variable - see tables QW-252 through QW-265.  That is, it applies only if impact testing is required. 

 

(2)  The DBTT is typically shifted to higher temperatures with greater time at temperature during sub-critical PWHT. (DBTT = ductile to brittle transition temperature)

 

(3)  Therefore, the Code is concerned that, at a minimum, the PQR PWHT time at temperature must be at least 80% of the actual fabrication PWHT time.  The PQR PWHT time can be longer than but not shorter than the 80% requirement.

 

In my experience, this is why general PQR's for impacts are performed with long PWHT times - often 8 to 24 hours.  If acceptable results are obtained (at the given test temperature) at long hold times then the PQR and WPS will be valid for much greater thicknesses or long aggregate times if multiple PWHT's are planned.  Note that low temperature holds for the purpose of hydrogen bake out are not required to be included (600~800F / 315~425C) by ASME Code.  But may be required to be included by customer specifications or other codes.

 

John

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From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Shashank Vagal
Sent: Friday, July 03, 2009 2:05 AM
To: materials-welding@googlegroups.com
Subject: [MW:2616] Re: QW 407.3

The underlying meaning eludes me; why would one want to increase the soaking time at an additional cost and what not, over and above the WPS allowed one by way of a PQR? Something jinxes. Shashank Vagal --- On Tue, 30/6/09, PREM SHANKARDUTT NAUTIYAL <prem_nautiyal@rediffmail.com> wrote: From: PREM SHANKARDUTT NAUTIYAL <prem_nautiyal@rediffmail.com> Subject: [MW:2594] Re: QW 407.3 To: arunvani@gmail.com Cc: materials-welding@googlegroups.com Date: Tuesday, 30 June, 2009, 10:15 AM I think it is QW-407.2 you guys are referring, because QW407.3 does not appear in Sec.IX 2007 edition ! Regards Prem Nautiyal On Sun, 28 Jun 2009 19:41:18 +0530 wrote >you are right, rajagopal >arun > >On Sun, Jun 28, 2009 at 11:28 AM, rajagopal kannan < >rajagopal.kannan@gmail.com> wrote: > >> Hi, >> That is if you do heat treatment of your PQR Test coupon to 80 minutes >> soaking time, then you can write a WPS for production welds to the maximum >> of 100 minutes soaking time. >> Thanks, >> K.Rajagopal >> >>   On 6/27/09, Jamie Welding wrote: >>> >>> >>> Hi folks, >>> Can any one of u interpret the QW 407.3. >>> Especially the part PQR should be at least 80% aggregate times that in >>> production welds. >>> >> >>> > > >-- >ARUNVANI > >Smiling Opens the Heart > >Good feelings for others are like ointments that heal wounds and >re-establish friendships and relationships. Good feelings are generated in >the mind, are transmitted through your attitude and are reflected in your >eyes and smile. Smiling opens the heart and a glance can make miracles >happen. > >SMILE IS A COOLING SYSTEM OF HEART, >SPARKLING SYSTEM OF EYES, LIGHTING SYSTEM OF FACE, RELAXING SYSTEM OF >MIND.... >SO TO ACTIVATE ALL YOUR SYSTEM >==ALWAYS KEEP SMILING== > >> > PREM S NAUTIYAL CELL : 9820313278

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