Duplex Stainless Steel

Duplex Stainless Steel (DSS) refers to the ferrite and austenite each account for about 50%, generally the content of less phase at least also need to reach 30% of Stainless Steel. In the case of low C content, the Cr content is between 18% and 28%, and the Ni content is between 3% and 10%. Some steels also contain alloying elements such as Mo, Cu, Nb, Ti, and N. We are a China duplex stainless steel products supplier and supply duplex stainless steel products wholesale. Contact us!

This kind of steel has the characteristics of aaustenite and ferrite stainless steel. Compared with ferrite, it has higher plasticity and toughness, no room temperature britteness, intergranular corrosion resistance and welding performance are significantly improved, while also maintaining the 475℃ britteness of ferrite stainless steel and high thermal conductivity, with superplasticity and other characteristics. Compared with austenitic stainless steel, the strength is high and the resistance to intergranular corrosion and chloride stress corrosion is significantly improved. Duplex stainless steel has excellent corrosion resistance, and it is also a low nickel stainless steel.

Its main feature is that the yield strength can reach 400-550mpa, which is 2 times that of ordinary stainless steel, so it can save materials and reduce equipment manufacturing costs. In terms of corrosion resistance, especially under the conditions of harsh medium environment (such as seawater, high chloride ion content), the resistance to pitting corrosion, crevice corrosion, stress corrosion and corrosion fatigue of duplex stainless steel is significantly better than that of ordinary austenitic stainless steel, which can be comparable to high alloy austenitic stainless steel.

Common grades of Duplex Stainless Steel: S31803(2205), S32750(2507), S32760

S31803 (2205)

Corrosion resistance of S31803 (2205):

1. Uniform corrosion: Due to the chromium content (22%), molybdenum (3%) and nitrogen content (0.18%) of 2205 duplex steel, the corrosion resistance of 2205 is better than 316L and 317L in most environments.

2, local corrosion resistance: the content of chromium, molybdenum and nitrogen in 2205 duplex steel makes it have a strong resistance to pitt-corrosion and gap corrosion in oxidizing and acidic solutions.

3. Stress corrosion resistance: the biphasic microstructure of 2205 duplex steel helps to improve the stress corrosion cracking resistance of stainless steel. In the presence of a certain temperature, tension, oxygen and chloride, chloride stress corrosion will occur in austenitic stainless steel. Because these conditions are not easily controlled, the use of 304L, 316L, and 317L is limited in this regard.

4. Corrosion fatigue resistance: the high strength and corrosion resistance of 2205 duplex steel make it have high corrosion fatigue resistance. Processing equipment is susceptible to corrosive environments and loading cycles, and the characteristics of 2205 are well suited for such applications.

Applications of S31803 (2205):

Neutral chloride environment, oil refining industry, petrochemical and chemical industry, chemical industry pipeline, oil and gas industry, pulp and paper industry, fertilizer industry, urea industry, phosphate fertilizer industry, the water environment, energy and environmental protection industry, light industry and food industry, food and pharmaceutical industry equipment, high strength structure, subsea pipeline, desulfurization of range hood, Osmosis desalination equipment, sulfuric acid plant, Marine engineering fasteners, etc.

S32750 (2507)

S32750 (2507) is a duplex stainless steel that combines many of the excellent characteristics of ferritic and austenitic steels. Due to its high chromium and molybdenum content, it embodies excellent resistance to pitting corrosion, crevice corrosion and uniform corrosion. The two-phase microstructure ensures that the steel has high stress corrosion cracking resistance and high mechanical strength. In addition, it has the characteristics of strong resistance to chloride pitting, high thermal conductivity and low thermal expansion coefficient.

Compared with S32205 duplex steel, S32750 has higher strength and corrosion resistance. Compared with 904L, it is more resistant to corrosion caused by mixing dilute sulfuric acid with chloride ions. It has higher yield strength and lower ductility compared to austenitic stainless steel. S32750 Super duplex steel also has high impact strength and is not suitable for use at temperatures higher than 570°F or 300°C because prolonged exposure to this environment can lead to reduced toughness.

Applications of S32750 (2507):

1) Desalination plants, high pressure reverse osmosis plants and subsea pipelines;

2) offshore platforms, heat exchangers, underwater equipment, fire fighting equipment and seawater treatment equipment;

3) Chemical processing industry, utensils and pipeline industry;

4) Mechanical parts (high-strength, corrosion-resistant parts);

5) Oil and gas industry equipment;

6) Corrosion resistant parts of chemical tanker;

7) Energy industry flue gas desulfurization system, industrial washing system, absorption tower;

8) oil refining, fertilizer and paper making, etc.

S32760

S32760 (F55, 1.4501) is a high alloy super duplex stainless steel, mainly used in a variety of strong erosion natural environment. S32760 duplex steel has strong compressive strength and corrosion resistance, and is key to organic chemical production and processing, petrochemical equipment and deep-sea machinery and equipment. It has strong resistance to fluoride corrosion, high heat transfer and low linear expansion coefficient. High chromium, molybdenum and nitrogen components make it highly resistant to plaque erosion, crack erosion and other erosion work ability. S32760 duplex steel excellent comprehensive type can be better than the general duplex steel, such as 2205, S31803 and so on.

S32760 duplex steel can be resistant to a variety of strong oxidants and organic acids, in addition to its high copper content so that it has extraordinary resistance to non-oxidizing acid corrosion working ability, S32760 also resistant to strong acid corrosion, but S32760 duplex steel should not be applied in the long-term operating temperature above 300℃, because above the temperature here, The ductility of the raw material will be significantly reduced.

Main applications of S32760:

Neutralization fluoride natural environment, refinery industry, petrochemical and chemical industry, chemical industry with transportation pipeline, crude oil and natural gas industry, pulp and paper industry, fertilizer industry, the industrial production of urea solution, under industrial production, the surface of the natural environment, the electric energy production and environmental protection industry, light industry and food industry, Food and pharmaceutical industry production machinery and equipment, high-toughness parts, deep-sea pipelines, range fume desulfurization, infiltration of salt elimination machinery and equipment, sulfuric acid plant, Marine technical standard parts, etc.