duplex stainless steel:bar

Expanding use of duplex stainless steel (marketing department of Shanghai HY Industry Co., Ltd)


  • So far, duplex stainless steel has made great progress both in the development of new steel grades and in the improvement of new production and processing modes, but these have not increased the market share of duplex stainless steel. However, a large number of stable or in the rising industry still provides many opportunities for the application of duplex stainless steel. These industries include shipbuilding, construction, wind power and offshore oil and gas. Once the European and Chinese economies recover, the demand for duplex stainless steel will increase and thus gain market share.

  • Although duplex stainless steel has good intrinsic quality, and with the continuous development of new manufacturing processes and new steel grades, it has also expanded many new applications, but for some reason, the amount of duplex stainless steel only accounts for about 1% of the overall stainless steel.

2, offshore demand

  • Offshore oil and gas sector continues to lead the demand for duplex stainless steel. Many suppliers are using the offshore oil and gas development boom to reposition themselves, so that the majority of suppliers in the UK, the North Sea is the focus of their attention.

  • To meet the demands of the subsea oil and gas market, JohnBell Pipeline Equipment has invested heavily in an order for duplex and super duplex stainless steel pipelines, fittings and flanges. UK pipeline producer IPPGroup has a new 7,000-ton forming capacity tee forming press, which can be used to produce tee pipe in duplex, super duplex, nickel-based alloy and stainless steel materials, whether seamless, welded or hollow. UK-based PipXtra has added duplex stainless steel UNS31803 seamless tubes in sizes ranging from 1/2″ NB to 8″ NB to its inventory. UKNorthSea witnessed Vallourec’s order from Technip because of the manufacture of super duplex stainless steel pipeline, which is used in the Edradour project operated by Total.

3, duplex stainless steel project

  • ABJ built two multi-stage flash evaporators for the Takreer carbon black and delayed coking units in Abu Dhabi. The evaporator is made of duplex stainlesssteel.

  • Otto Kump signed a supply contract to provide 22,000 tons of 2205 duplex stainlesssteel to a gas field in Oman, the order is Otto Kump’s largest duplex stainlesssteel order.

  • TechnipUmbilicals signed a contract with Vallourec for the Edradour project operated by Total in the UK North Sea. The contract includes super duplex stainlesssteel welded tubes for pipe cables.

  • Australia and Brazil are also hot areas for offshore construction. In Australia, the booming LNG industry has stimulated sales of duplex stainlesssteel, and Civmec has begun construction of a special deepwater facility made of the special material at its coastal equipment plant in Henderson, Western Australia. A contract has also been signed with Technip Australia to manufacture and test 68 sets of deep sea subsea crossover pipe connectors for the Citroen-operated Wheatstone project. The contract is for the manufacture of spools in different materials including corrosion resistant alloy (CRA) Inconel, super duplex stainlesssteel and carbon steel, with tube diameters from 6″ to 44″. Shell’s PreludeFLNG project will use coated duplex stainlesssteel.

  • Raccortubi has recently established a subsidiary in Brazil. Petrobras has ordered butt-welded pipe fittings from the company.

  • DeutscheEdelstahlwerke (DEW) started up a new metallurgical refining center in Witten, Germany. The center mainly produces offshore duplex stainlesssteel and super duplex stainlesssteel and other products.

  • Sandvik’s new Oil & Gas business unit is formed to market duplex stainlesssteels and nickel-based alloys for offshore applications.

  • Stalatube selected Otokunp’s LDX2101 duplex stainless steel as a key construction material for its new StalaWind wind turbine tower.

  • To reduce sulfur emissions from ships, Valmet (formerly Metso) designed two gas-fired desulfurization units for which Otokump supplied 40 tons of 2507, 2205 duplex stainless steel and 254SMO® and 316L stainlesssteels.

  • Otto Kump supplied 4,000 tons of LDX2404 duplex stainlesssteel for the Husab uranium project in Namibia, Africa. PVIIndustries ordered LDX2101, an economical duplex stainless steel, from Otto Kump to replace the carbon steel used in the water heater.

  • Shanghai HY Industry Co., Ltd supplied Shanghai Electric with duplex stainlesssteel plates for desalination. This is the first time China’s desalination project using domestic materials.

4、Other industries

  • duplex stainless steel:sheetThe application of duplex stainlesssteel on chemical ships is also growing. Japan approved the use of NSSC2120 duplex stainlesssteel to replace austenitic stainlesssteel to build chemical ships. Sweden’s small boats have begun to use Sandvik and Otokunp super duplex stainlesssteel 2507. the weight of the hull and its superstructure is only one-third of ordinary steel. Since no painting is required, no maintenance is needed.

  • Duplex stainless steel can also be used to manufacture wind turbines. In order to increase efficiency and take full advantage of the strong winds at high altitudes, wind turbines under construction are getting larger and larger (at altitudes above 100m, the turbine output increases by 1% per meter). For this reason, Stalatube designed the StalaWind wind turbine tower made of LDX2101® duplex stainless steel hollow tubes. These wind power towers are not only structurally robust, but also lightweight and easy to transport and install.

  • The use of economical duplex stainlesssteel for construction and infrastructure will further increase. The German Institute for Building Technology (DIBT) approved the use of LDX2101® (EN1.4162) and LDX2404® (EN1.4662). Manufacturers of building and structural components can now use economical duplex stainlesssteel directly without prior application. The economical duplex stainlesssteel in the approval includes coil and plate products up to 30mm thick and bar products up to 40mm in diameter, as well as components made of these products. TISCO won the Metallurgical Science and Technology Award for the use of duplex stainlesssteel bars in the cross-sea bridge in 2014.

5、New steel grades

  • The needs of users have been driving the development of new steel grades of duplex stainlesssteel. Users using Otokunpu duplex stainlesssteel want to develop a new duplex stainlesssteel: its corrosion resistance is greater than or equal to PRE = 28, mechanical strength is greater than the economic duplex stainlesssteel 2304, the alloy content should be lower than 2205. For this purpose Otokunp developed EDX2304™ (Table 1) based on 2304 by improving corrosion resistance and increasing strength. It is used for offshore superstructure components (fire protection, blast walls and safety gates, structural pipes, pipe supports and clamps, cable bridges and ladders) and vessels in the chemical industry.

  • To address the poor forming properties of the majority of duplex stainlesssteels, Otto Kump has developed two duplex stainlesssteels, FDX25TM and FDX27TM (Table 2), which outperform other duplex stainlesssteels in terms of fatigue and elongation properties through phase change induced plasticity (TRIP). These steels are mainly used in heat exchangers, flexible pipelines, pump parts, automotive components, domestic hot water pipes and beer kegs.

6, duplex stainless steel and coatings

  • The cost of developing offshore oil and gas storage is increasing dramatically. Statoil vice president said from 2003 to 2014, the cost of subsea oil and gas projects doubled, the use of high-alloyed duplex stainlesssteel is one of the reasons. Some manufacturers are now considering using lower grades of duplex stainlesssteel with coatings to replace higher alloy grades. They have found that thermally sprayed aluminum (TSA) can alleviate stress corrosion cracking, hydrogen stress cracking, pitting and crevice corrosion in 22% and 25% Cr stainlesssteels. TSA-coated duplex stainlesssteels are being used in Shell’s PreludeFLNG project. The same technology has long been used on carbon and austenitic stainlesssteels to extend the life of offshore facilities. Equipment located at the top of the FPSO like compressors, related piping and valves are benefited by the use of TSA technology.

7、New manufacturing process

  • Due to the phase change induced plasticity (TRIP) technology, making FDX materials possible. In fact, TRIP technology has long been used for carbon steel, the purpose is to combine strength and toughness together. Another technology affecting the manufacture of stainlesssteel is 3D printing (a new type of technology). This technology has had a significant impact on nickel and titanium alloys, but it is unclear whether the extent of the impact on duplex stainlesssteel is so great. Still, there are some encouraging signs so far, with tests showing increased density and strength in high-density powder metallurgical duplex stainlesssteels produced by mixing water and gas atomized powders. The use of advanced process technology – electric arc furnace (EAF) + argon oxygen decarburization furnace (AOD) + high performance atomization (HPA) and hydrogen annealing – produces a product of far better quality than that produced by induction furnaces, thus improving consistency.

  • Super duplex stainlesssteel can now be manufactured by 3D printing, and Sandvik uses gas atomized metal powder as a raw material for 3D printing to produce a variety of stainlesssteel products. In addition to other alloys and steel grades, Sandvik also uses this method to produce duplex stainlesssteel 329 and 2507SD products.


  • Duplex stainlesssteel products are increasingly used in a wide range of new manufacturing technologies, yet it is puzzling that the production of duplex stainless steel accounts for only 1% of total stainless steel production. Shanghai HY Industry Co., Ltd found the reason, such as product form and size single, price advantage is not large, marketing failure (business will be duplex stainless steel as “technology” products rather than as a conventional product marketing). Nevertheless, he estimates that the production of duplex stainless steel will increase by 7% to 8% per year.

  • Traditionally, the demand for duplex stainlesssteel in Europe is greater than in the United States, and once Europe comes out of the economic downturn, the market for duplex stainless steel is likely to increase. Southeast Asia is likewise likely to drive growth in duplex stainless steel, with the world’s top producers there accounting for four-fifths of the total, and when China’s economy picks up speed again, it may also stimulate consumption of duplex stainless steel.

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