Duplex stainless steel is an alloy of iron, chromium, nickel, and molybdenum, with a two-phase microstructure composed of austenite (a solid solution of iron and chromium) and ferrite (iron). It offers high strength and corrosion resistance and is used in various industries, including petrochemicals and marine applications.
Duplex steels are called so for their dual-phase microstructure, i.e. austenitic and ferritic. This unique structure provides superior mechanical properties compared to other types of stainless steel. Duplex steel is known for its good mechanical properties.
Better toughness and ductility are traits executed better in duplex stainless steels when compared to ferritic steels. The nitrogen, chromium, molybdenum and nitrogen content make it immune from chloride pitting and crevice corrosion resistance stress-corrosion cracking resistance is excellent in duplex steels. Duplex stainless steel grades have lower nickel and molybdenum content when compared to other austenitic steels. The lower alloying content of elements makes these steel types much more cost-effective. The sectional thickness of duplex steels can be altered due to the increased yield strength compared to standard austenitic steels. Due to their stress corrosion cracking resistance, duplex steels are used in brewing, process plants, hot water tanks, and more. High strength, excellent corrosion resistance, and lower pricing make duplex steels more popular.
Duplex stainless steels are available in different grades depending on their composition and properties. Duplex stainless steel grades such as 2205, 2507, and Zeron 100 offer exceptional corrosion resistance to various corrosive environments, including chloride-containing media. These duplex stainless steel ASTM grades also exhibit high strength, making them ideal for structural components such as beams, columns, and plates.
Duplex steel buttweld fittings made from are widely used in piping systems because they provide reliable performance under high-pressure conditions. Similarly, due to their high strength and durability, duplex stainless steel round bars are made.
Duplex steel coils are commonly used in heat exchangers, providing efficient heat transfer while withstanding harsh operating conditions. Duplex steel tubes are also preferred over other materials for their excellent resistance to pitting and crevice corrosion. Duplex steel fasteners offer superior mechanical & corrosive properties, making them suitable for use in offshore structures exposed to seawater.
Super duplex steel flanges are used extensively in oil and gas, offering exceptional performance under extreme pressure conditions. They are also employed in chemical processing plants where they provide superior resistance to stress corrosion cracking.
In addition to its many benefits, duplex stainless steel is cost-effective compared to other high-performance alloys. We are proud to offer a wide range of various industry-specific duplex steel products from some of the top-rated manufacturers in the business. From tubing and piping to valves and pumps or fittings, our selection of products provides a reliable and cost-effective solution to your needs. Our experienced manufacturers are dedicated to manufacturing high-grade duplex steel products that meet industry specifications, no matter the application or use case. Manufacturers make our products with advanced technology, precise dimensions, and excellent surface finish that can last years. As an ISO-certified company, we strive to provide superior service and uncompromised quality. We have years of experience supplying the highest quality duplex stainless steel products at competitive prices to customers worldwide. So if you have any questions about our selection of ASTM duplex stainless steel products, contact us today for answers!
Duplex stainless steel is a type of stainless steel that has a two-phase microstructure consisting of both austenitic and ferritic phases. This unique combination of phases gives duplex stainless steel distinctive properties, including high strength, excellent corrosion resistance, and good weldability.
Duplex stainless steel has a range of hardness values depending on the specific grade and heat treatment. Typically, the hardness of duplex stainless steel falls within the range of 150-290 HB (Hardness Brinell). However, it is essential to note that various factors can affect the hardness.
The IGC (Intergranular Corrosion) test is a commonly used test for evaluating the susceptibility of duplex stainless steel to intergranular corrosion. This test involves exposing the material to a corrosive solution at an elevated temperature for a specified period and examining the microstructure and corrosion resistance.
The IGC test is essential for duplex stainless steel because it has a dual-phase microstructure which can make it susceptible to intergranular corrosion under certain conditions. The test can help determine whether the material meets specific industry standards such as ASTM A923 or ISO 3651-2.
During the IGC test, specimens are typically immersed in an acidic solution containing copper sulfate and sulfuric acid at an elevated temperature ranging from 40°C to 70°C for several hours. The exposure time and temperature may vary depending on the specific industry standard.
After exposure, the specimens are examined under a microscope to detect any evidence of an intergranular attack. The results are compared against acceptance criteria specified in industry standards such as ASTM A923 or ISO 3651-2.
Duplex stainless steel has a wide range of typical applications of duplex stainless steel include:
Chemical processing: Due to its high strength and resistance to corrosive chemicals, chemical processing plants use Duplex stainless steel for equipment such as pressure vessels, heat exchangers, and piping systems.
Oil and gas industry: Duplex stainless steel is used in offshore oil rigs, pipelines, and subsea equipment due to its excellent resistance to chloride stress corrosion cracking (SCC) and pitting corrosion.
Desalination: Duplex stainless steel is used in desalination plants for equipment such as pumps, valves, and piping systems due to its high strength and excellent resistance to seawater corrosion.
Pulp and paper industry: Duplex stainless steel is used in pulp mills for equipment such as digesters, bleach towers, and evaporators due to its excellent resistance to corrosive chemicals.
Structural applications: Due to its high strength-to-weight ratio, duplex stainless steel is also used in structural applications such as bridges, buildings, and storage tanks.
Yes, duplex stainless steel is magnetic.
Austenitic stainless steel has a single-phase microstructure consisting of austenite, while duplex stainless steel has a two-phase microstructure consisting of both austenitic and ferritic phases. Duplex stainless steel offers higher strength and better corrosion resistance than austenitic stainless steel, making it suitable for more demanding applications.
Stainless steel is a broad term for corrosion-resistant steel containing at least 10.5% chromium. On the other hand, Duplex stainless steel is a specific type of stainless steel with a two-phase microstructure consisting of both austenitic and ferritic phases. This dual-phase structure gives duplex stainless steel higher strength and better corrosion resistance than traditional austenitic stainless steel. Additionally, duplex stainless steel has improved toughness and ductility compared to many other types of stainless steel.
Here are some duplex stainless steel welding procedures:
Three main types of duplex stainless steel are lean duplex, standard duplex, and super duplex.
ASTM A240 and ASTM A790 are the primary ASTM standards for duplex stainless steel.