2 coupons in one pqr

[alicuas]

i came across a pqr with two test coupons, one is 1 dia inch sch 80 and the other is 1 dia inch sch 40. the sch 80 pipe was used for tensile test, the sch 40 pipe was used for guided bend test. is this possible? if yes, what thickness should be followed in making the wps?

 

[Duwe6]

Assuming that either ASME or AWS is the governing code, the answer is a resounding NO!

A PQR is a report of the fabrication of a coupon, to prove out a welding procedure - WPS. It is not unusual for 1 WPS to be supported by two [or more] PQR's. But one coupon per PQR record/report. Two coupons requires two sets of bends and tensiles.

We both know that the Sch40 was easier to bend, thus an easier test to pass. That may be the reason for the thinner coupon to be used.

 

[weldtek]

In some cases like that described above, multiple coupons may be necessary as 1" pipe won't yield all of the test coupons necessary. Using test assemblies of different thicknesses for bends and tensiles is not the norm.

 

[Guest102023]

If this is legit for ASME or AWS I would like someone to explain it to me.

 

[Duwe6]

It is POSSIBLE, with the prior concurrance of your AI, to use 2 1"NPS pipe coupons for 1 PQR, if they were welded identically and consecutively.

BUT, why in the world would want to. PQR coupons are typically plate, and over 6-inches long. Now 4ea. bends and 2ea. tensile coupons can be 'lifted' out of the coupon. As previously, a PQR/WPS is for proof of process and procedure variables. It has nothing to do with a welder's skill. Thus plate gives exactly the same PQR/WPS as 1 or more pipe coupons. And the price will be lower, due to the ease of cutting and machining the required 6 samples for tensiles & bends.

Then, with the WPS qualified, do you dstart certifying your pipe welders, in the 6G [or 2G plus 5G] position. This welder coupon can be RT's, UT'd [if 1/2" or thicker], or 2 bends. At the end of the week, running your PQR coupon on plate and qualing the welder later, on pipe, will be either the same price as trying to do both on one pipe coupon, or will be cheaper.

juliodavid Without proof of an AI's concurrance, I would reject that WPS/PQR as Out-of-Code and borderline fradulent.

 

[stanweld]

If one were foolish enough to qualify a welding procedure on 1-inch diameter pipe, at least 3 welded pipe coupons would be required.
Theoretically, the procedure could be so qualified under ASME IX; however, the thickness of qualification would be limited to 0.266" (2 x sch 40 thickness) and not 0.358" (2 x sch 80 thickness). Also there is no way that four face and root bend specimens (1 1/2" wide) could be obtained per QW-462.3(a) and QW-463.1(d) from a 1.315" OD pipe (4.455" outside circumference).

The WPS is not qualified per ASME IX.