A detailed explanation of the development history of duplex steel 2205 and super duplex steel 2507

A detailed explanation of the development history of duplex steel 2205 and super duplex steel 2507


 

Today, GNEE Steel will talk to you about the development history of this dual-phase steel.

The development of dual-phase steel originated in the 1930s. In 1936, a steel type named Uranus50 obtained the first dual-phase steel patent in France. So far, three generations of dual-phase steel have been developed, CV548.



The first generation of dual-phase steel is represented by Sweden's 3RE60 and the United States' AISI329. 3RE60 is a dual-phase steel specially developed to improve chloride stress corrosion cracking resistance. AISI329 duplex steel is widely used in heat exchanger pipes of nitric acid plants. The first generation of duplex steels had good performance characteristics but had limitations in the welded state. The heat-affected zone of the weld has low toughness due to excessive ferrite, and its corrosion resistance is significantly lower than that of the base metal. These limitations limited the use of first-generation duplex steels to specific applications in the non-welded state.



The invention of argon-oxygen decarburization, a stainless steel refining process in 1968, made it possible to produce a series of new stainless steel grades. One of the many advances brought about by AOD is the addition of the alloying element nitrogen. Adding nitrogen to duplex steel can make the toughness and corrosion resistance of the heat-affected zone in the welded state close to the properties of the base metal. Nitrogen also reduces the formation rate of harmful intermetallic phases. Nitrogen-containing duplex steels are called second-generation duplex steels. 2205 dual-phase steel is a representative steel type of the second generation of dual-phase steel and is widely used in many fields such as offshore oil platforms, chemical industry, and papermaking.



The super duplex steel developed in the late 1980s belongs to the third generation of duplex steel. Representative grades include 2507 duplex steel, UR52N, Zeron100, etc. This type of steel is characterized by low carbon content, high molybdenum and high nitrogen content. This type of steel has excellent pitting corrosion resistance. The pitting equivalent is greater than 40.



Judging from the current research and production levels, Europe and the United States are at the leading level in the research and development, production and user recognition of dual-phase steel. Representative companies include Sweden's Outokumpu and Sandvik, as well as American manufacturers. In Asia, Japan and South Korea are the main producers of duplex steel.



Research on dual-phase steel in China began in the mid-1970s. Beijing Iron and Steel Research Institute was the first to start research work in this area. The developed 00Cr18Ni5Mo3Si2 has been incorporated into national standards. Currently, TISCO and Baosteel are able to supply commercial materials in China. Taiyuan Iron & Steel Co., Ltd. began to develop 2205 dual-phase steel in the late 1990s and launched its products on the market in 2005. Baosteel also began to develop Cr22 dual-phase steel in 2006. It is worth noting that some large domestic private enterprises are also at the forefront of R&D and promotion of duplex steel, such as Jiuli Group, Wujin Steel Pipe, etc.

In recent years, with the continuous rise and large fluctuations in Ni prices, dual-phase steel has shown a trend of development at both ends. First, give full play to the resource saving advantages of duplex steel and develop economical duplex steel such as 2101. Its development direction is to replace the traditional 300 series austenitic stainless steel. Its design concept uses Mn and N elements to replace Ni, Mo, etc. precious metals. Second. It is to give full play to the characteristics of high strength and good corrosion resistance of duplex steel, develop super duplex steel represented by 2507, and partially replace super austenitic stainless steel 904L, 254SMo, etc.



In China, duplex steel is currently dominated by 2205. The output of economical duplex stainless steel and super duplex stainless steel 2507 is constantly growing. The production of special super duplex stainless steel is in a state of continuous trial production and application. The application fields are also constantly expanding. While further consolidating the application in the petrochemical industry, it has continuously expanded its applications in oil and gas transportation, chemical tanker manufacturing, nuclear power, equipment manufacturing, construction and other fields, and has continued to explore the international market. It can be seen from the development of duplex steel at home and abroad that 2507 duplex steel is a resource-saving, high-performance stainless steel product. Its production and application are in line with the future development direction of stainless steel.

Duplex steel is a high-tech, high-value-added product. Its development and production not only reflect the technical level of stainless steel production enterprises, but also create more economic benefits for enterprises. It is foreseeable that the proportion of dual-phase steel used will further expand in the future.