We’re considering switching a 12-in Sch 40 reclaimed-water header from 316L to 2205 duplex to curb chloride pitting and improve life-cycle sustainability. Supplier claims about 30% lower GWP via about 80% scrap EAF melt, but I’m weighing that against higher filler costs and stricter heat-input control during welding. Any real-world feedback on 2205 performance at grooved couplings and CUI spots in 300–700 ppm Cl- service?
We swapped a 12-in reclaimed header to 2205 and the only headache was roll-grooved ends — cold work around the groove turned into the first rust/crevice spots — so we now specify machined cut grooves for all ‘grooved couplings’; costs a touch more but it solved it — are you cutting or rolling?
Leaning 2205 is fine, but lock down the WPS: ER2209 filler, low heat input (about 0.5–1.5 kJ/mm), interpass <150°C, and N2 purge on roots — our reclaimed header stopped pitting, and the only callbacks were unpickled welds near couplings. For grooved joints, specify machined (not roll) grooves and require ASTM A380/A967 pickling/passivation plus EPDM gaskets; that killed the crevice spots @m_thompson0723 noted. The “about 30% GWP” checks out, but ask for the mill’s EPD/recycled content (e.g., https://www.outokumpu.com/sustainability/epd) since scrap mix swings it.