Duplex Steel Pipes

Duplex Steel Pipes from Newton are seamless and welded pipes manufactured in duplex and super duplex stainless steel grades, combining the strength of ferritic steel with the corrosion resistance of austenitic stainless steel. Their dual-phase microstructure gives roughly double the yield strength of standard austenitic grades like 304 or 316, along with superior resistance to chloride stress corrosion cracking and pitting, making them the standard choice wherever seawater, brine or aggressive chemical exposure would degrade conventional stainless steel.

Duplex Steel Pipes

Newton manufactures Duplex Steel Pipes to ASTM/ASME A790 (seamless and welded) and A928 (welded with filler metal), in duplex grade UNS S31803/S32205 and super duplex grades UNS S32750 and S32760, available from 1/2″ NB to 24″ NB across a full schedule range. Pipes are hot-finished or cold-drawn depending on size, followed by solution annealing and rapid quenching to achieve the correct balanced ferrite-austenite phase ratio that gives duplex steel its characteristic combination of strength and corrosion resistance.

These pipes are specified for offshore and marine piping, desalination plant process lines, seawater cooling systems, chemical and petrochemical process piping handling chlorides or sour service, pulp and paper industry equipment, and pressure vessels where weight savings from higher yield strength justify the material premium over standard stainless steel. Their strength allows thinner wall sections for a given pressure rating compared to austenitic grades, which can offset the higher per-tonne cost of duplex material.

Every pipe is tested for phase balance (ferrite content), pitting resistance equivalent number (PREN), mechanical properties and intergranular corrosion resistance, with mill test certificates issued in accordance with ASTM A790. Positive material identification (PMI) and third-party inspection can be arranged for critical offshore and desalination projects where material verification is a procurement requirement.

Newton sources Duplex Steel Pipes from India’s specialized duplex pipe manufacturers with dedicated solution-annealing and quenching lines, consolidating grade and size-specific orders into fully certified export shipments for offshore, marine and process industry buyers worldwide.