S32750

S32750, also known as UNS S32750, is a super duplex stainless steel alloy designed for high corrosion resistance and strength. It features a duplex microstructure with approximately equal proportions of ferrite and austenite, giving a combination of high strength and superior corrosion resistance compared with conventional austenitic stainless steels. The alloy was developed for service in highly corrosive media containing chlorides, such as seawater, oil and gas production environments, and chemical processing.

The nominal composition typically includes around 25% chromium, 4-7% nickel, 3-5% molybdenum, and nitrogen as an alloying addition to stabilize the duplex structure; exact ranges vary by standard and product form.

S32750 offers outstanding resistance to pitting, crevice corrosion, and stress corrosion cracking in chloride-containing environments, along with good mechanical strength and toughness. It can be heat treated only in a limited way; in practice, it relies on its duplex microstructure for strength and corrosion resistance. Fabrication requires welding procedures that preserve the duplex phase, with filler metals chosen to match the alloy, and post-weld heat treatments when required to restore austenite-ferrite balance.

Common applications include offshore and subsea oil and gas equipment, chemical processing lines, heat exchangers, valves, fittings, and other components exposed to aggressive brine and chlorinated environments.

S32750 is specified in several international standards and is available in plates, bars, tubes, pipes, and fittings, reflecting its role as a high-performance material for harsh service conditions.