Duplex stainless steel is a kind of stainless steel composed of austenite and ferrite in a certain proportion. It has integrated the excellent individual properties of austenitic stainless steel and ferritic stainless steel and eliminated their shortcoming.
Because of its special dual-phase microstructure and special performance, it can not be classified as austenitic stainless steel or ferritic stainless steel. It has become the third type of stainless steel. The excellent surface performance allows it to be applied to many scenarios. The market of duplex stainless steel has been growing rapidly in the past 10 years and its applications have become more and more widespread.
Duplex stainless steel alloy has undergone an evolution over the past few decades in terms of production process and quality. In the early stage of production, the most common practice was to use scrap steel as the raw material, which had a uncontrollable and unstable quality. With the development of smelting technology, a lot of research and development in optimizing process has been conducted to ensure the stability, repeatability and predictability of the production process.
This also led to the emergence of many advanced and high-performance duplex stainless steel alloys, including duplex 2205, LDX2101 and duplex 2304. These varieties are all applied to a variety of areas, such as paper making, chemical and petrochemical processing, oil and gas production, seawater processing facilities, desalination and membrane technology, pharmaceutical, food and beverage processing and storage, etc.
The most distinctive characteristics of duplex stainless steel alloys is an extremely high mechanical strength, yielding strength of up to 800MPa and higher, as well as excellent resistances to corrosion, pitting and stress corrosion cracking. The highest levels of resistance to general and localized corrosion are usually achieved with an alloy containing a minimum of 25% Cr, 6% Ni and 3.5% Mo.
Duplex stainless steel also has excellent weldability and superior performance in both cold and hot formability. Its superior mechanical and corrosion properties make it an excellent choice for various applications. Furthermore, its high strength and corrosion resistance make it a perfect choice for applications in extreme situations, such as high temperature, high pressure and exposed surfaces.
The cost of duplex stainless steel is quite a bit higher than most ordinary austenitic stainless steel, however, the superior performance and durability of the material can outweight the extra cost.
With the rapid development of science and technology and the continuous improvement of production process, the application range of duplex stainless steel is still expanding. It is expecting a higher level of application in the future and will become an irreplaceable high-end material in the future.
