How many PQR's would be required

[rocket686]

I am going to be welding a tank using three different types of material. Each of the three types will be welded to itself and each of these three types will be welded to the other two types. In all there will be six different combinations of material when welding.The three material types are: A333 Gr 6 (P1 Group 1), A572 Gr 50 (S1 Group1), and A588 Gr A (S3 Group 1). What would be the minimum number of supporting PQR's required in order to write six WPS's to cover all combinations? This question will only pertain to FCAW process.

 

[sayee1]

Rocket
1. What is the code you are welding/qualifying to? Since P No & S No mentioned, I presume qualification of procedures is as per ASME Section IX.
2. What about the diameters and thicknesses, I presume they are similar ranges for these three materials specified.
3. A333 Gr 6 (P1 Group 1?? Is this P1 Group 1 or S 1 group 1, refer paragraph 3 of QW 420.2 which says materials as per ASTM like A333 Gr 6 shall be S1 Group 1 and material as per SA333 Gr 6 shall be P1 Group 1)
4. Is the testing with impact testing or not? I mean would it be necessary to consider supplementary essential variables or not? I am assuming no supplementary essential variables as not mentioned otherwise.
5. A333 Gr 6 (S1 Group 1) & A572 Gr 50 (S1 Group1) can be covered by one PQR qualified on A333 Gr 6/A572 Gr 50(Refer QW 420.2), and A588 Gr A (S3 Group 1). Even if you are using SA333 Gr 6(P1 Gr1) and PQR qualified on SA333 gr 6, it will cover all P1 group 1 and S 1 group 1 materials including A572 Gr 50. The combination of these will also be covered. The PQR will also cover the welding of these to materials to themselves or the combination in case of supllementary essential requirements.
6. Two (2) PQRs will be required to qualify the welding of A588 Gr A (S3 Group 1) to itself and to the materials specified in note 5 above.
Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
End of all knowledge is the attainment of immortality!

 

[nousakmj]

If you were using these materials for a structural application, the A572 and A588 materials are listed, so welding them to themselves or each other would be prequalified for the SMAW, FCAW, GMAW and SAW processes within the limits of AWS D1.1. A333, however, would be considered an unlisted material, so you would have to develop and test a PQR for welding of A333 to itself and another PQR for welding A333 to the other materials.
The previous response regarding qualification to ASME SC IX is correct.

Matt Nousak, P.E.
Senior Staff Engineer
Middough Associates Inc.
nousakmj@middough.com

 

[GRoberts]

The previous post is correct. For ASME IX qualification, you need do a test with P1 to P1 (not S1) and P1 to S3. Also assuming no impact requirements, so group numbers are non-essential. Do not use the S-1 for qualification as using P1 will qualify S1, but not the other way around.

 

[rocket686]

I apologize for not being more thorough in my original question.
1. Welding will be done to ASME Sec. 9 .
2. Material thickness ranges from 3/16" to 1"
3. Charpy vee notch impact testing to -20 deg. C. @ 15 ft/lbs (27 joules)is required for all materials.
4. I would prefer using 1/16" Flux Core wire when possible.

Thanks

 

[nousakmj]

For your purposes, the "S" numbers apply. The charpy impact requirement forces you into considering supplementary essential variables, but that isn't insurmountable.
15 ft-lbf at -20 deg C works out to 15 ft-lbf at -4 deg F. For FCAW, E7XT-1 is rated for 20 ft-lbf at 0F. If you control your heat input properly, you'll probably get there using this filler metal, but a 75% (or 80%) argon + 25% (or 20%) carbon dioxide shielding would help. Straight carbon dioxide shielding gas probably won't make it on a consistent basis.
E7XT-5 will also work with an argon-co2 mix, but is intended for flat and horizontal welding.
E7XT-6 (for flat and horizontal) and E7XT-8 (for all positions) are self-shielded FCAW wires (spatter-matic specials) that are also rated at 20 ft-lbf at -20 deg F, and should do the job.
For all intents, you should only need to pick one filler metal wire for the FCAW process -- and that comes down to whether or not you want gas shielding or self-shielding. I always favor gas shielding, especially for shop environments -- but I'll admit that I'm not a fan of spatter-matic on any given day.
After that, ASME SC IX makes things pretty straightforward.
You'll need to qualify the A588 to itself at two thicknesses -- I would use 1/4" and 1/2" to satisfy the requirements of QW-403.6. That gets you a qualified range of 1/8" up to 1". QW-424 effectively says that a P3 (or in this case S3) welded to itself also qualifies for a P3 (or S3) to a P1 (or S1), if all other essential variables are the same.
You'll also need to run a pair of A572 Gr 50 test plates, again using 1/4" and 1/2" thicknesses.
The 1/16" wire should do the trick, unless you have more plate in the 1/4" and thinner range being used, in which case an 0.052" (or even 0.045&quot diameter wire may be useful. In any case, qualify the test plates using the 1/16", because if you can make your Charpy values with that heat input (which you will have to control), you will be able to use smaller diameter wires whose heat input is equal to or less than that of the 1/16" wire.
4 PQR's are what you need. Lotsa luck.

Matt Nousak, P.E.
Senior Staff Engineer
Metallurgist/Welding Engineer
Middough Associates Inc.
middough.com