Zeron 100 / F55 (UNS S32760): The Super Duplex Stainless Steel

 

What is the composition and key advantage of Zeron 100?
Zeron 100 has a balanced composition of about 25% Cr, 7% Ni, 3.5% Mo, 0.7% W, and 0.25% N. This gives it a high PREN (>40) for outstanding pitting/crevice corrosion resistance and very high mechanical strength (~550 MPa yield). Its key advantage is delivering performance close to nickel alloys at a fraction of the cost.

Where is it primarily used?
It is specified for critical components in offshore oil & gas (piping, manifolds), seawater cooling systems, chemical tankers, and flue gas desulfurization scrubbers where chlorides, acids, and high pressures are present.

How does it compare to standard duplex 2205?
It offers significantly higher strength and corrosion resistance, especially in hot chloride solutions. It bridges the gap between 2205 and high-nickel alloys, allowing for thinner, lighter sections in demanding designs.

What are the fabrication considerations?
Welding and hot working require strict procedure control to avoid harmful intermetallic phase formation. Using matching or over-alloyed filler wire and controlling interpass temperature is critical to preserve properties.

When should an engineer specify Zeron 100?
Specify it when 2205 is insufficient for the environment's chloride level, temperature, or pressure, but a full nickel alloy is cost-prohibitive. It is ideal for life-cycle cost optimization in severe service.