Building a WPS from a PQR: So many questions

Date 10-20-2015 15:26

Hey All,

I have here, a PQR that passed a large number of tests. The PQR was a 27mm plate, double V groove. The groove was backed with GMAW, then filled with SAW (CJP)

After sending this out to a testing firm, everything came back a-o-kay.

With that I'd like to build a WPS off of this, but it seems a bit goofy in a number of aspects.

Ex. 1: Thickness

Gable 4.2, page 139 of D1.1:2010 we see "WPS Qualification - CJP Groove Welds: Number and type of Test Specimens and Range of Thickness and Diameter Qualified (Dee 4.5) (Dimensions in millimeters)

Part 1 Tests on Plate shows

That if the Nominal Plate Thickness (T) Tested was 25 and over -> And there were 2 Reduced Section Tension (See fig 4.14), and 4 Side Bend (see fig 4.13), then the Nominal Plate thickness qualified is a Minimum of 3mm, and a maximum of Unlimited.

There for, I can use these steps on 3mm plate to 50 mm plate. That sounds good to me.

Ex. Part 2: When the PQR was created, 6 passes were made in total. And as we can imagine running these 6 same passes on 5mm of material seems a bit excessive. Is there a way to note "can be accomplished with a single pass per side?" I'm not finding anything in D1.1 that says "add or remove the number of passes" ?

Ex. Part 3: Adjust ability
Table 4.2/4.2 shows that I have the following adjust ability without the need to re-qualify a wps:

+/- 10% Amps
+/- 7% Volts
+/- 10% Wire Feed Speed
+/- 15% Travel Speed

BUT with all of that under Electrical Characteristics 9)a) we see the condition of:

"An increase in heat input or volume of weld metal deposited per unit length of weld, over that qualified. The increase may be measured by either of the following: J/in = (Volts x Amps x 60) / Travel Speed
Weld Metal Volume - An increase in bead size, or a decrease in the length of weld bead per unity length of electrode.

Doesn't this nullify any ability to increase the amps, volts, as those increase the heat input?

Just...so very confused as to what is going on here. Really starting to question how I passed the CWI exam....

By In Tension (**)

Date 10-20-2015 16:56

If you're using Table 4.6 (where you find #9a) then I assume impact testing is required? If that's the case, you have a bigger problem than your number of fill passes or being able to tweak the electrical characteristics... your 27mm PQR does not cover base metal thickness less than 5/8" (16mm). You'll need to provide another PQR for the thinnest base metal you wish to weld in production. See Table 4.6, #2.

By Bowler_Hat (**)

Date 10-20-2015 18:12

I'm not quite following you.

PQR Supplementary Essential Variable Changes for CVN Testing Applications Requiring WPS Requalification for SMAW, SAW, GMAW, FCAW, and GTAW

"2) Minimum thickness qualified is T or 5/8 in [16mm] whichever is less, except if T is less than 1/4 in [6mm], then the minimum thickness qualified is 1/8 in [3mm]"

We qualified a 27mm plate, therefor:

Minimum thickness qualified is (27mm) or 16mm whichever is less, [16mm is less], then the minimum thickness qualified is 3mm.

Could you help me work my way through this bit, as I'm not seeing the 'minimum thickness qualified is 5/8 in.'

Thanks!

By KBNY

Date 10-20-2015 18:50

Does the contract documents require CVN testing? Because table 4.6 is a supplementary table that only applies when CVN testing is required. Otherwise, you do not need to apply those variables when writing your WPS's.

If you do have to apply table 4.6, then In Tension is correct... item 2) would limit your minimum thickness to 5/8" (16mm).

By Bowler_Hat (**)

Date 10-21-2015 14:13

Our contract does in fact require CVN testing on all butt joints (A.K.A. all SAW welds). I've written a new post to address this specific idea.

Outside of that...if this wasn't what was required...what of the other questions illustrated in the original post?

Thanks!

By Kix

Date 10-26-2015 15:28

Ex. Part 2: When the PQR was created, 6 passes were made in total. And as we can imagine running these 6 same passes on 5mm of material seems a bit excessive. Is there a way to note "can be accomplished with a single pass per side?" I'm not finding anything in D1.1 that says "add or remove the number of passes" ?

You can write multiple WPS's off of one PQR. It's good practice for your 5MM weldment to have it's own WPS based off your existing supporting PQR.

BUT with all of that under Electrical Characteristics 9)a) we see the condition of:

"An increase in heat input or volume of weld metal deposited per unit length of weld, over that qualified. The increase may be measured by either of the following: J/in = (Volts x Amps x 60) / Travel Speed
Weld Metal Volume - An increase in bead size, or a decrease in the length of weld bead per unity length of electrode.

Doesn't this nullify any ability to increase the amps, volts, as those increase the heat input?

Not necessarily. With the increase in volts and amps can come the increase in travel speeds that can in turn keep your heat input in check with the essential variables. Travel speed is also an essential variable so everything has to be monitored so when audited you are within spec.

Just...so very confused as to what is going on here. Really starting to question how I passed the CWI exam....

Where and with who did you take your CWI exam? Just messin with ya man! Don't sweat it brotha. We all started somewhere. Keep studying, asking questions, and learning on here. There is so much one can learn on these forums.