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QW-403.5, Change of group number

QW-403.5, Change of group number

Postby gerdmil » Thu Nov 21, 2013 3:52 pm

Dear all,
Could you please explain the clause QW-403.5 of ASME IX? I have went again and again through that clause but I am not able to understand what does it say.
For example, QW-403.5 (c) defines that:
a procedure qualification shall be made for each P-number Group number combination of base metals
and immediately after that it says:
even though procedure qualification tests have been made for each of the two base metals welded to itself
To my interpretation those two statements are equal to each other. Moreover, I am not sure that I have fully understood the rest of the QW-403.5 (c) regarding qualification of combination of base metals, etc. Could you please give some examples?
thanks
gerdmil
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Re: QW-403.5, Change of group number

Postby mohd » Thu Nov 21, 2013 5:24 pm

dear,

As you know if impact is required, then the Group number is an essential variable.
Let's give two examples

Example-1
sentence-1: "a procedure qualification shall be made for each P-number Group number combination of base metals"
sentence-2: "even though procedure qualification tests have been made for each of the two base metals welded to itself'"
WPS-1 # P1G1 to P1G1, if no impact requirement, then qualifies also for P1G1 to P1G2, refer to sentence-1&2
WPS-2 # P1G2 to P1G2, if no impact requirement, then qualifies also for P1G2 to P1G1, refer to sentence-1&2
WPS-3 # P1G1 to P1G2 qualified with impact, qualifies also for the combination of WPS-1 & WPS-2 with impact.

Example-2
WPS-1 # P1G1 to P8G1 qualified with impact, qualifies only for this combination, not P1G1 to P1G1 & P8G1 to P8G1.

Hope this help.

regards,
mohd
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Re: QW-403.5, Change of group number

Postby wefel » Wed Nov 27, 2013 11:22 am

Mohd,

Since I disagree with your "Example-2" as well as I think we shall explain the clause QW-403.5 in more detail, please let me give the below interpretation and kindly let me know if your are in agreement (please note that all of the example PQR are considered to have been performed with impact test and for all of the production welding examples there is impact test requirement).

The statement "a procedure qualification shall be made for each P-number Group number combination of base metals" means that the welding of P1G1 to P1G2 needs procedure qualification even though procedure qualification tests have been made for each of the two base metals welded to itself. In other words if we have:
PQR1: P1G1 to P1G1
PQR2: P1G2 to P1G2
then the welding of base metals P1G1 to P1G2 needs separate procedure qualification except if the PQR1 and PQR2 have the same essential and supplementary essential variables since the base metals are assigned to different Group numbers within the same P-number (specified by QW-403.5).

Regarding the statement "when base metals of two different P-number Group number combinations are qualified using a single test coupon, that coupon qualifies the welding of those two P-number Group numbers to themselves as well as to each other using the variables qualified", it means that if we have:
PQR3: P1G1 to P2G4
this PQR qualifies for the weldings
P1G1 to P1G1, P1G1 to P1G4, P1G1 to P2G1, P1G1 to P2G4, P1G4 to P1G4, P1G4 to P2G1, P1G4 to P2G4, P2G1 to P2G1, P2G1 to P2G4, P2G4 to P2G4.

regards
wefel
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Re: QW-403.5, Change of group number

Postby mohd » Wed Nov 27, 2013 12:15 pm

Dear Mr wefel,

With utmost respect what you said and demonstrated by examples is correct, but you have to see also the essential variables as per QW-250.

As I said P1G1 to P8G1 cannot qualify for P1G1 to P1G1 because we cannot weld this materials (P1G1 to P1G1) with ER309L, am I right?
As I said P1G1 to P8G1 cannot qualify for P8G1 to P8G1 because we cannot weld this materials (P8G1 to P8G1) with ER309L, am I right?

When we qualify WPS we have to look into this combination as well.

Hope it is clear.

reagrds,
mohd
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Re: QW-403.5, Change of group number

Postby wefel » Wed Nov 27, 2013 1:35 pm

Dear Mohd,
Thanks for the explanatory comments though I regret to tell you that I don't agree with your thoughts because if you have qualified procedure using base metals P1G1 to P8G1 and filler metal ER309L then you qualify also for P1G1 to P1G1 with the same filler metal (in reality no one uses ER309L to weld carbon steel since the ER309L is much more expensive form carbon steel filler metals) as well as you qualify for P8G1 to P8G1 with the same filler metal (in reality it is not a common practice to weld for example SS 316 using ER309L filler metal since the latter may not be the appropriate filler metal for the service environment for which the material SS 316 has been selected).
regards
wefel
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