Base material grouping is a supplymentary essential variable, even though it's a supplymentary essential variable, both DSS & SDSS have P 10H and Gr. 1. As per ASME SDSD WPS is permitted to write with DSS PQR, still impact testing is not there you want to use SDSS wire itself, yes it is permitted, if impact testing is there and you want to use SDSS wire, it's not permitted and requalification is required,
Below consideration I have addressed previous need to be taken into consideration,
However, beyond the code requirements, from a metallurgical and performance standpoint, DSS and SDSS differ significantly in their ferrite-austenite phase balance requirements. Achieving the correct phase balance is critical and is strongly influenced by welding heat input. SDSS, in particular, has a higher PREN (Pitting Resistance Equivalent Number) requirement compared to DSS.
To achieve the required PREN and phase balance in SDSS weld metal, nitrogen is commonly added to the shielding and backing gas. Nitrogen is a strong austenite stabilizer and also contributes to an increase in PREN, thereby improving corrosion resistance.
If a WPS is qualified for DSS using pure argon as the shielding gas, and it is later proposed to use an argon–nitrogen mixture (for Eg: Ar + 2% N₂) for SDSS welding, this change would require requalification of the PQR. This is because the addition of nitrogen significantly affects weld metal chemistry, phase balance, and mechanical and corrosion properties, making it a metallurgically significant change even if not explicitly listed as an essential variable in all cases.
That said, if the required mechanical properties, corrosion resistance, and phase balance are successfully achieved using the same gas composition qualified for DSS (i.e., pure argon), ASME Section IX permits its use, as long as all applicable essential and supplementary essential variables remain within the qualified range.
On Mon, 15 Dec 2025, 8:35 pm syed kauser ahmed, <syedkauserahmed@gmail.com> wrote:
As per ASME Section IX – QW-403.5:No, a change from one Group Number to another Group Number within the same P-Number shall be considered an essential variable and requires requalification of the WPS.--On Mon, 15 Dec 2025, 16:29 Alex Kumar Antony, <alexkantony@gmail.com> wrote:Can we use Duplex WPS for Super Duplex, kindly quote with the help of codeThanks--
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