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Structural Steel
Published in Fiona Cobb, Structural Engineer’s Pocket Book, 2020
Duplex stainless steels are so named because they share the strength and corrosion resistance properties of both the austenitic and ferritic grades. They typically contain 21-26% chromium, 4-8% nickel and 0.1-4.5% molybdenum. These steels are readily weldable but are not so easily cold rolled. Duplex stainless steel is normally used where an element is under high stress in a severely corrosive environment. A commonly used alloy is Duplex 2205 (European grade 1.44062).
High Alloy Steels
Published in P. C. Angelo, B. Ravisankar, Introduction to Steels, 2019
Duplex stainless steels are used in heat exchangers, tubes and pipes for production and handling of gas and oil, heat exchangers and pipes in desalination plants, mechanical and structural components for corrosive environments, pipes in process industries handling solutions containing chlorides, utility and industrial systems such as rotors, fans, shafts and press rolls where high corrosion fatigue strength is required – cargo tanks, vessels, piping, and welding consumables for chemical tankers. A wide range of stainless steels are used throughout the paper making process. For example, duplex stainless steels are being used in digesters to convert wood chips into wood pulp.
Introduction
Published in Vipulkumar Ishvarbhai Patel, Qing Quan Liang, Muhammad N. S. Hadi, Concrete-Filled Stainless Steel Tubular Columns, 2019
Vipulkumar Ishvarbhai Patel, Qing Quan Liang, Muhammad N. S. Hadi
The duplex stainless steels are formed by a mixed microstructure of austenitic and ferritic stainless steels so that they have the best properties of austenitic and ferritic grades. The 0.2% proof stress and corrosion resistance of duplex stainless steels are higher than those of austenitic grades. However, the weldability and formability of duplex stainless steels are lower than those of austenitic ones. The duplex stainless steels can be hardened by cold working. The UNS S31803 grade is the most commonly used duplex stainless steel in engineering structures. The chemical composition of duplex stainless steels has 22% chromium, 5% nickel, and 3% molybdenum. The mechanical properties of duplex stainless steels are listed in Tables 1.1 and 1.2.
Numerical analysis of topographic and Volta potential profiles during corrosion of duplex stainless steel in chloride solution
Published in Corrosion Engineering, Science and Technology, 2022
Yuan Li, Shan Qian, Boxin Wei, Y. Frank Cheng
Duplex stainless steels have been widely used in industry due to their excellent mechanical properties and corrosion resistance. The reason that the DSS is resistant to corrosion in aqueous environments is owing to a high content of alloying elements such as nickel, chromium and molybdenum [1]. However, the heterogeneous microstructure such as austenite (γ) and ferrite (α) causes an electrochemical inhomogeneity, affecting corrosion and localised corrosion resistances in the environments, especially in the presence of chloride ions [2–4]. Moreover, preferential corrosion tends to occur on a specific phase contained in DSS, where an enhanced electrochemical corrosion activity is experienced locally [5]. Nowadays, the SKPFM has been accepted as a promising tool to study corrosion of metals containing complex microstructure and multiple microphases, such as DSS [6,7].
Influence of microstructural morphology on pitting corrosion resistance of duplex stainless steel weld metals
Published in Welding International, 2020
Kota Kadoi, Shun Takada, Hiroshige Inoue, Masatake Hojo, Yuma Yoshioka
Duplex stainless steel is a stainless steel in which the main elements are Cr, Ni, Mo and N and which comprises a metallic structure in which the ferrite-austenite volume ratio is 1: 1. It is a steel which combines the merits of ferrite stainless steel, which has excellent stress corrosion cracking resistance and austenitic stainless steel, which has excellent workability and weldability. Further, since duplex stainless steel is a mixed structure of fine-grain austenite and ferrite, its strength, particularly yield strength, near room temperature is high and in addition it has a lower Ni content than austenitic stainless steel and is thus less costly yet with a similar excellent corrosion resistance. SUS329J3L, SUS329J4L and other widely-used duplex stainless steels were developed in the 1970s and with the recent reductions in steel plate weight by reductions in rare metals and reduction in thickness, duplex stainless steel has attracted renewed attention because of its stable cost, due to the small content of nickel the cost of which is highly variable, its corrosion resistance and weldability. Demand for this is multifaceted, and it is used in seawater heat exchangers in chemical industry plants, manufacturing and storage tanks in the food industry, chemical tankers, floodgates and other river infrastructure and pipes for the transport of oil produced in off-shore oilfields and ancillary equipment [1].
Hot cracking susceptibility and solidification segregation analysis by computer simulation in duplex stainless steels
Published in Welding International, 2019
Dong Cho Kim, Tomo Ogura, Yoshihiro Tanabe, Shotaro Yamashita, Kazuyoshi Saida
Duplex stainless steel, a high-strength, highly corrosion-resistant stainless steel with a two-phase austenitic-ferritic structure with characteristics that make it an excellent material, is widely used in chemical and energy-related plants, marine environment equipment, heat exchangers and other examples of a high-temperature, high corrosion environment. In addition to original duplex stainless steel (standard duplex stainless steel), duplex stainless steels also include newly developed reduced alloy duplex stainless steel (lean duplex stainless steel), super duplex stainless steel and hyper duplex stainless steel. Lean duplex stainless steel, which may be used as a substitute material for general-use austenitic stainless steel (SUS304, SUS316), has a reduced content of costly nickel and molybdenum, and maintains a similar corrosion resistance to general-use austenitic stainless steel while achieving double its strength. This makes thin-plate design possible and has attracted considerable attention as a stainless steel which reduces the usage of rare metals and is very economical. Super duplex stainless steel, which may be used in highly corrosive environments, has a corrosion resistance equivalent to super austenitic stainless steel but has greater strength and superior cost performance. In recent years, hyper duplex stainless steel, which has both corrosion resistance and strength superior to super duplex stainless steel, has been developed but its applications are currently extremely limited.