AWS D1.1 PWHT

Date 09-10-2013 02:55

Hi All,

Table 4.6 point 8 of AWS D1.1 (2010) states "A change in the PWHT temperature and/or time ranges. The PQR test shall be subject to 80% of the aggregate times at temperature(s). The PWHT total time(s) at temperature(s) may be applied in one heating cycle".

Does that mean that if we intend to PWHT for 100 minutes in production that we need to PWHT the PQR test coupon for 80 minutes?

Also, what is the PWHT time range that you should write on the WPS assuming the example above.

Thanks

By 803056

Date 09-11-2013 01:16

PWHT is approved by the engineer, not the CWI. It should also be the engineer that specifies the PWHT.

Al

By gastonM (**)

Date 10-28-2013 22:53

Normally there is a separate procedure for PHWT, that specifies other variables. But conceptually, we as inspectors, should reject WPS or procedures that indicates time ranges (including heating and cooling) times ranges over 100 minutes. See comentary 3.14 of D1.1, there is an explanation and a warning for dont use ASME with new structural steels.

By apwec

Date 10-13-2013 20:07 Edited 10-16-2013 11:51

Al,
I don't agree with you. The variable 8 of table 4.6 of AWS D1.1 is clear. So when CVN test is required then you have to comply with this supplementary essential variable if PWHT is needed.
Firefly,
You are fully right since in such a case you have to PWHT the PQR test specimen for at least 80 minutes. The same is specified in ASME IX as well. Please have a look at this link:
http://www.weldinguide.com/gdanastasiadis/viewtopic.php?f=5&t=424
regards
apwec

By 803056

Date 10-13-2013 22:21

I am not sure what it is that you disagree with, unless it is just to weasel in a reference to your website.

Al

By welderbrent (*****)

Date 10-14-2013 03:58

Must I really bite my tongue here??? This is so messed up!!

Firefly may be correct, the problem is that those determinations are not in the CWI's scope of work. They are to monitor/observe and report. Regardless of rather they are in house or TPI. The engineer is responsible for those calculations, determinations, specifications and placing the all important stamp of approval.

I guess we are truly stuck with the 10% that didn't get the memo: never mind, I won't quote the memo. They wouldn't understand it anyway.

Have a Great Day, Brent

By 99205

Date 10-14-2013 12:44

"the problem is that those determinations are not in the CWI's scope of work" There are those that believe their CWI card allows them great, decision making powers.

By 803056

Date 10-14-2013 13:41

With great authority comes great responsibility.

If the CWI assumes more authority than is granted by the applicable code, the CWI better be prepared to step up and accept the financial responsibility for the consequences of their decisions when things go wrong.

Postweld heat treatment is more involved than simply looking up the minimum stress relief temperatures in a code. Few CWI have the training or education to make decisions regarding proper PWHT.

Whether one is an engineer, doctor, or CWI, one must recognize the limits of their capabilities and call on specialist when called upon to do something that is beyond their education, training, or experience.

As good as the CWI seminars are, they do not prepare a CWI to take on responsibilities that are not listed in AWS B5.1.

Best regards -Al

By welderbrent (*****)

Date 10-14-2013 15:23

AMEN!

Have a Great Day, Brent

By Superflux (****)

Date 10-14-2013 16:54

What???
I thought that CWI card gave me free reign to make them do anything.

By welderbrent (*****)

Date 10-14-2013 23:22

By eekpod

Date 10-17-2013 18:46

Superflux.
That's the problem, some guys do think that and try it :wink: