In the early 1900s, the first stainless steels were pure austenitic, ferritic, or martensite. The first dual-phase steel with a combination of ferrite and austenite phases was developed in 1930 by Sweden’s Avista Steel Works (which later became Outokumpu). The plant began selling the first two duplex stainless steels to customers who needed to reduce intergranular corrosion, which can occur with ferritic stainless steels.
In the early days, duplex steels were used to manufacture castings, rods and plates for the pulp and paper industry and for high-temperature applications due to their good corrosion resistance and castability. By 1932 they accounted for 6.5% of the total global stainless steel market of 5,500 tons.
What is duplex stainless steel?
Duplex stainless steel is a stainless steel composed of two stainless steel material grains, austenite and ferrite. The term “duplex” refers to the two-phase microstructure of ferritic and austenitic steel grains. The proportions of ferritic and austenitic stainless steel grades in duplex stainless steel are approximately equal (i.e. 50% each).
Duplex stainless steel is extremely corrosion-resistant because its microstructure contains both austenite and ferrite phases. This makes them ideal for use in environments that require high strength and high corrosion resistance, such as marine applications, chemical processing plants, and oil and gas production.
Advantages of duplex stainless steel:
Duplex stainless steels are becoming increasingly popular due to their excellent corrosion resistance and mechanical properties. Compared to austenitic stainless steels, duplex stainless steels have higher strength and resistance to pitting, stress cracking and crevice corrosion.
There are many benefits to using duplex stainless steel, including:
●Increased strength and durability
●Better resistance to corrosion and pitting
●cut costs
●Environmentally friendly production process
●Increase versatility
If you are looking for a high-quality, durable and cost-effective material, duplex stainless steel is a great choice.
Applications of duplex stainless steel:
Duplex stainless steel is widely used in various industries, including:
●chemical processing
●oil and gas
●Desalination
●pulp and paper
●Food & Drink
●drug
●Building and Construction
●The marine environment
Composition of duplex stainless steel:
Duplex stainless steel is composed of two different phases: austenite and ferrite. The composition of duplex stainless steels varies, but typically contains about 22% chromium, 3% molybdenum, and 5-6% nickel. They also contain trace amounts of manganese, silicon and nitrogen. Depending on the grade of duplex stainless steel, the two phases are mixed in different proportions. The austenitic phase is characterized by high chromium and nickel content, which provides excellent corrosion resistance. The ferrite phase gives steel its high strength and toughness.
Properties of duplex stainless steel:
Duplex stainless steels have higher strength and hardness than austenitic stainless steels. They also have better corrosion resistance in chloride-containing environments. Additionally, they are less susceptible to stress corrosion cracking and pitting than austenitic stainless steels.
Duplex stainless steel grades:
There are several grades of duplex stainless steels, each with its own specific composition and properties. Some common duplex stainless steel grades include:
- Duplex 2205 (UNS S32205 / S31803): Duplex 2205 is one of the most widely used duplex stainless steel grades. It contains approximately 22% chromium, 5-6% nickel, 3% molybdenum, and 0.2-0.3% nitrogen. This grade offers good corrosion resistance, high strength, and excellent resistance to stress corrosion cracking and pitting corrosion. It is often used in applications such as chemical processing, oil and gas exploration, and marine environments.
- Duplex 2304 (UNS S32304): Duplex 2304 is a lean duplex stainless steel with a lower alloy content compared to Duplex 2205. It contains approximately 23-24% chromium, 3-4% nickel, 0.1-0.2% nitrogen, and small amounts of molybdenum and manganese. This grade offers good resistance to localized corrosion and stress corrosion cracking, making it suitable for applications in the pulp and paper industry, chemical processing, and structural components.
- Duplex 2507 (UNS S32750): Duplex 2507 is a super duplex stainless steel with higher alloy content, offering enhanced corrosion resistance and strength compared to standard duplex grades. It contains approximately 25% chromium, 7% nickel, 4% molybdenum, and 0.3% nitrogen. This grade is well-suited for applications in aggressive environments such as seawater, chemical processing, and oil and gas production.
- Duplex LDX 2101 (UNS S32101): Duplex LDX 2101 is a low-nickel, nitrogen-enhanced duplex stainless steel with a balanced composition of approximately 21.5% chromium, 1.5% manganese, 5% nickel, and 0.22% nitrogen. This grade offers good strength, corrosion resistance, and cost-effectiveness, making it suitable for a wide range of applications, including structural components, pressure vessels, and heat exchangers.
- Duplex UR2202 (UNS S32202): Duplex UR2202 is a duplex stainless steel with a composition that includes approximately 22% chromium, 2% molybdenum, and 3% nickel. It offers good resistance to pitting and crevice corrosion, making it suitable for applications in the chemical, petrochemical, and oil and gas industries.
These are just a few examples of the many duplex stainless steel grades available, each designed to meet specific performance requirements for different applications. The selection of a particular grade depends on factors such as the environment, temperature, corrosion resistance, mechanical properties, and cost considerations. Duplex stainless steels continue to gain popularity due to their excellent combination of strength, corrosion resistance, and cost-effectiveness, making them a preferred choice for a wide range of demanding applications.
Tianjin Anton Metal Manufacture Co., Ltd. is a company specializing in the production of various nickel-based alloys, Hastelloy alloys and high-temperature alloy materials. The company was established in 1989 with a registered capital of 10.0 million, specializing in the production and sales of alloy materials. Anton Metal’s products are widely used in aerospace, chemical industry, electric power, automobile, nuclear energy and other fields, and can also provide customized alloy material solutions according to customer needs. If you need to know the price consultation of alloy materials or provide customized alloy material solutions, please feel free to contact the sales staff.
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Post time: Apr-18-2024
