QW-407.2 ASME IX PWHT time

[ElCidCampeador]

QW-407.2 ASME IX

I have a PQR with PWHT time range of 210 min.

I have a WPS with PWHT of 96 min. (time range is the minimum required acc. to ASME VIII Div.1)

Welds are impact tested.

Question: may I use that PQR to cover this WPS? (assuming all other variables ok)

Some people say that 96min is less than 80% of 210min so I can't; others say that PQR PWHT time shall be above the 80% of 96min,(mine it's 210min): so I can use.
I'm confused .

Thanks

 

[david339933]

I assume you are stating you have a pqr and are making a wps....you can't have a wps without a pqr.

If you PWHT pqr coupon longer than required for your WPS you are ok. Problem comes with not PWHT long enough.

Ex: 1/2" PQR Coupon
Basemetal Qualified: 1/2" - 1".

But if you only PWHT for the 1/2" thickness you could not qualify to 1". You need to have PWHT at least 80% of the time required for 1" (48 mins.)

 

[ElCidCampeador]

It's not a problem of coupon lenght or thickness because my PQR covers it.
I don't understand if my PQR with that time range (210min) could cover the WPS for 96min PWHT required by ASME VIII Div.1, or I need a new PQR with different PWHT time range.

 

[david339933]

You are ok. Thickness was just an example as to how QW-407.2 works. If you don't understand how it works how can you justify? Just believe some guy on the internet?

 

[david339933]

Let's try this another way.

Example: 1/2" plate coupon for PQR
If you do a PQR with no impacts required you can PWHT the coupon per Sec VIII 1hr/inch. For 1/2" this will be 30mins. This will cover the WPS for the full range of basemetal qualified. (3/16"-1"..just put 1hr/inch under PWHT in the WPS)

If impacts are involved you won't be able to get 1" max thickness qualified because you didn't PWHT long enough per QW-407.2. This clause states you must PWHT to at least 80% of the PWHT time required for the max. thickness qualified. 80% of the PWHT time required for 1" is 60mins/inch * .8 = 48 mins.

You PWHT longer than required....therefore ok.

 

[DekDee]

This may help

Interpretation: IX-92-84
Subject: Section IX, QW-407.2, Postweld Heat Treatment
Date Issued: November 22, 1993
File: BC93-586
Background: A PQR was welded on a 2 in. thick P-No. 1, Gr. 2 material and post weld heat
treated at 1150°F for six hours (3 hr/in.) with supplementary essential variable requirements.

Question: Will this PQR support a WPS for a production weld in 2 in. thick P-No. 1, Gr. 2
material that is PWHT at 1150°F for 2 hours (lhr/in.)?
Reply: Yes.