Duplex to Super Duplex Welding 1

[sovog]

We have a small project where there is a requirement to weld Super Duplex 25% Cr S32750 to Duplex 22% Cr S31803.

If I am correct in my understanding of ASME IX QW 424.1 that any material assigned the same P No can be welded to any other material assigned the same P No.
They are both P No 10H Gr 1.

In order to avoid running a new WPS can we utilise a Super Duplex 25% Cr S32750 to weld these materials together?

I have some doubt in the back of my head that I have been here before and was not allowed, but can’t remember why.

 

[weldtek]

Normally impacts are required with duplex. Are you changing filler from what was used on the original PQR?

 

[sovog]

The S32750 we plan to utilise had impacts carried out @ -50°C.
We are to use Zeron 100 Tig wire as per this procedure.

 

[weldtek]

sovog,
My question was regarding filler classification. If impacts are applicable, which in duplex they generally are, supplementary variables become essential. That means you can't change classification of the filler without requalifying the procedure. You can review the other supplementary variables in QW 256.

 

[sovog]

weldtek

We are not changing the filler wire or classification from the original procedure used on the S32750 procedure.

We wish to utilise the S32750 procedure where instead of S32750 welded to itself, it would be welded to S31803.

No variables from that of the original S32750 procedure will change.

 

[weldtek]

sovog,
It sounds as though you may not be required by Code to requalify in this case, but, if you haven't already done so, I suggest you review your current WPS with the requirements of QW 256 and satisfy yourself that the new conditions won't violate any rules.
In my experience, customers often place requirements on duplex welding far in excess of Code rules, and, most would probably require a separate qualification for the base metal change you refer to.

 

[sovog]

weldtek

I have reviewed QW 256, apart from the change of 1 base metal which is still within the P No of the original procedure; we will not be making any other changes to the variables, which in my biased opinion does not violate the code.
Thanks for your opinion; you have clarified my thoughts that what we wish to do is more of a client requirement than a code issue.