Duplex stainless steel has the characteristics of austenitic stainless steel and ferritic stainless steel because of its austenitic + ferritic biphase structure, and the content of the two phase structures is basically equivalent. The yield strength can reach 400Mpa ~ 550MPa, which is twice that of ordinary austenitic stainless steel. Compared with ferritic stainless steel, duplex stainless steel has higher toughness, lower brittleness transition temperature, and significantly improved intergranular corrosion resistance and weldability.

Core material characteristics

High strength and lightweight

The yield strength is twice that of 304/316L, allowing for thinner wall thicknesses, reducing weight and material costs.

Superior resistance to chloride ion corrosion

Resistant to pitting and crevice corrosion: far exceeding 316L in seawater, salt water, and desulfurization flue gas environments;

Resistant to chloride stress corrosion cracking (SCC): 304/316 are highly prone to cracking in chlorinated warm water, while 2205 has almost no such risk;

Resistant to sulfide corrosion: suitable for oil and gas media containing H₂S, meeting NACE corrosion prevention standards.

Excellent welding performance

Can be welded using TIG/MIG/arc welding, with compatible welding materials ER2209/E2209; generally no need for heat treatment after welding, strictly controlling heat input to avoid phase imbalance and σ phase brittleness.

Low thermal expansion coefficient and better heat conductivity

Compared to austenitic stainless steel, it has less thermal expansion, lower thermal deformation, and more stable heat exchange equipment. Limitations

When the temperature exceeds 315℃, brittle σ phase will precipitate and the toughness will significantly decrease. At extremely low temperatures below -80℃, the toughness will be severely reduced, making it unsuitable for extremely low-temperature equipment.

Chemical composition of each grade:

Performance data of various grades of metal (for reference only) :

Physical properties of each grade:

Application fields

Marine Engineering: Desalination equipment, seawater pumps, offshore platform pipelines, ship cargo holds, coastal anti-corrosion structures;

Petrochemicals: Oil and gas transportation pipelines, sulfur-containing medium pressure vessels, heat exchangers, refining equipment;

Environmental De-Sulfurization: Power plant FGD flue gas desulfurization towers, absorbers, flue ducts;

Papermaking and Pulping: Cooking equipment, bleaching washing equipment;

Chemical and Fertilizer: Urea plants, acid-base reaction vessels, chloride storage tanks;

Others: Food processing equipment, coastal bridges, high-pressure water treatment equipment.