Application and Development of Duplex Stainless Steel

Duplex stainless steel consists of ferrite phase and austenite phase in its quenched structure, and the content of the minimum phase may reach 30%. Duplex stainless steel is formed on the basis of 18-8 austenitic stainless steel by increasing the content of Cr or adding other ferrite elements, which makes the steel have two-way structure of austenite and ferrite, and saves Ni alloy.

Duplex stainless steel has the advantages of both ferritic stainless steel and austenitic stainless steel by correctly controlling chemical composition and heat treatment process due to the characteristics of two-phase structure of bidirectional stainless steel. Duplex stainless steel reduces the brittleness and crystal growth tendency of high Cr voxel steel due to the presence of austenite, while maintaining its excellent toughness and weldability. The existence of ferrite improves the yield strength, intergranular corrosion resistance and chloride stress corrosion resistance of austenite.

Elemental Composition and Performance Application of Duplex Stainless Steel

20191012092450 10200 - Application and Development of Duplex Stainless Steel

Duplex stainless steel is a kind of material whose microstructure is composed of ferrite phase and austenite phase, each of which accounts for about 50%. In practical use, one of them is suitable between 40-60%.
According to the characteristics of two-phase structure, through the correct control of chemical composition and heat treatment process, the excellent toughness and weldability of austenitic stainless steel are combined with the high strength and chloride stress corrosion resistance of ferritic stainless steel, so that the two-phase stainless steel is a kind of excellent corrosion resistance, high strength and easy to process and manufacture. Type of steel. Their physical properties are between austenitic stainless steel and ferritic stainless steel, but closer to ferritic stainless steel and carbon steel. The resistance to chloride pitting and crevice corrosion of duplex stainless steel is related to the content of chromium, molybdenum and nitrogen. The resistance to yttrium corrosion and crevice corrosion of duplex stainless steel can be similar to 316 stainless steel or higher than that of seawater stainless steel such as 6% MO austenitic stainless steel. The chloride stress corrosion cracking resistance of all duplex stainless steels is obviously stronger than that of 300 series austenitic stainless steels, and the strength of duplex stainless steels is much higher than that of austenitic stainless steels, showing good plasticity and toughness.
Duplex stainless steel products in various forms:

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Chemical composition

The main alloying elements of Z in duplex steel are Cr, Ni, Mo and N. Among them, Cr and Mo increase ferrite content, while Ni and N are austenite stable elements. Some steels also contain elements such as Mn, Cu and W. Cr, Ni and Mo can improve the corrosion resistance. In the chloride-containing environment, its pitting and crack corrosion resistance is particularly good.
1. Chemical constituents (%)
Table 1

C

Cr

Ni

Mo

N

P

S

SAF2205

0.030

21.0-23

4.5-6.5

2.5-3.5

0.08-0.2

0.030

0.030

SA2507

0.030

24.0-26

6.0-8.0

3.0-5.0

0.32

0.035

0.020

2. Mechanical properties of duplex stainless steel (duplex steel) depend on product type and Z final heat treatment. The following table lists the specified limits.
Table 2

Test temperature

RP0.2N/MM2

RM0.2N/MM2

A5%

 SAF2205

Room temperature

450

620

25

100

360

 

 

150

335

 

 

200

310

 

 

250

295

 

 

300

285

 

 

SA2507 room temperature

550

800

1000

46

100

450

 

 

200

400

 

 

 

 

 

 

 

Duplex stainless steel (duplex steel) has good mechanical properties in the temperature range of – 50 280 C. When duplex steel withstands high temperature of over 300 C for a long time, its micro-computer structure will change and the toughness will decrease. However, the decrease of toughness does not necessarily affect the properties of materials at working temperature. Compared with austenitic steels with similar alloy content, the matrix materials of duplex steel and super duplex steel possess core-like pitting resistance and crack corrosion resistance, but generally have excellent resistance to stress corrosion organic acid corrosion. It is well known that the pitting resistance grade is expressed by the equivalent value of pitting resistance PREN in industry.
3. Physical properties: The heat conductivity of dual phase steel is listed in the table below and compared with 316L.
Table 3

Temperature

Grade

SAF2205

SAF2507

AISI316L

20

19

16

15

100

19

17

16

200

21

19

17.5

300

23

20

19

The thermal expansion of duplex stainless steel (duplex steel) is similar to that of carbon steel, which makes duplex steel have obvious advantages over austenitic stainless steel. Microstructure of UNSS31803 duplex stainless steel used by our company for West-to-East Gas Pipeline is as follows: its ferrite content is 54%.

I. Properties of Duplex Stainless Steel

Advantages of Duplex Stainless Steel
1. Compared with austenitic stainless steel, duplex stainless steel has the following advantages:

  • (1) Yield strength is more than twice as high as that of common austenitic stainless steel, and it has enough plasticity and toughness for forming. The wall thickness of tanks or pressure vessels made of duplex stainless steel is 30-50% less than that of austenite commonly used, which is conducive to reducing costs.
  • (2) Dual-phase stainless steel with the lowest alloy content has higher stress corrosion cracking resistance than austenitic stainless steel, especially in the environment containing chloride ions. Stress corrosion is an outstanding problem that ordinary austenitic stainless steel is difficult to solve.
  • (3) The corrosion resistance of 2205 duplex stainless steel is better than 316L austenitic stainless steel, which is most commonly used in many media. Super duplex stainless steel has very high corrosion resistance. In some media, such as acetic acid, formic acid, etc., it can even replace high alloy austenitic stainless steel, even corrosion resistant alloy.
  • (4) It has good local corrosion resistance. Compared with austenitic stainless steel with the same alloy content, its wear resistance and fatigue corrosion resistance are better than those of austenitic stainless steel.
  • (5) The linear expansion coefficient of austenitic stainless steel is lower than that of austenitic stainless steel, which is close to that of carbon steel. It is suitable for joining with carbon steel and has important engineering significance, such as producing composite plates or linings.
  • (6) Dual-phase stainless steel has higher energy absorption capacity than austenitic stainless steel under dynamic or static load conditions. It has obvious advantages in dealing with unexpected accidents such as collision and explosion, and has practical application value.

2. Compared with ferritic stainless steel, duplex stainless steel has the following advantages:

  • (1) The comprehensive mechanical properties of ferritic stainless steel are better than that of ferritic stainless steel, especially its plasticity and toughness. It is not as sensitive to brittleness as ferritic stainless steel.
  • (2) Except for stress corrosion resistance, other local corrosion resistance is better than that of ferritic stainless steel.
  • (3) Duplex stainless steel is much better than ferritic stainless steel in cold processing and cold forming properties.
  • (4) Welding performance is much better than that of ferritic stainless steel. Generally, there is no need for preheating before welding and no need for heat treatment after welding.
  • (5) The application range is wider than that of ferritic stainless steel.

II. Defects of Duplex Stainless Steel

1. Compared with austenitic stainless steel, the disadvantage of duplex stainless steel is as follows:

  • (1) The universality and versality of the application are not as good as that of austenitic stainless steel, and the heat resistance is low. The service temperature of the austenitic stainless steel should be controlled below 300 C.
  • (2) Its plastic toughness is lower than that of austenitic stainless steel, and its cold working hardening effect is greater than that of austenitic stainless steel. In the initial stage of tube and plate deformation, it needs to exert a greater force to deform, so that the internal stress of tube and plate is larger. Duplex stainless steel containing 25% Cr is more difficult to hot work than austenitic stainless steel.
  • (3) In order to avoid the appearance of harmful phase and damage the performance, the process of heat treatment and welding should be strictly controlled in the presence of medium temperature brittle zone.

2. Compared with ferritic stainless steel, duplex stainless steel has the following disadvantages: high content of alloy elements, relatively high price, and generally ferrite does not contain nickel.
Classification and Classification of Duplex Stainless Steel
So far, the development of duplex stainless steel has gone through three generations. At present, all countries in the world have their own brands. Typical duplex stainless steel can be divided into four categories:
The first type belongs to low alloy type. The representative brand is UNS S32304 (23Cr-4Ni-0.1N). The steel does not contain molybdenum. The pitting corrosion equivalent PRE value is 24-25. It can replace AISI304 (0Cr18Ni9) or 316 (OCr17Ni12Mo2) in stress corrosion resistance.
The second type belongs to medium alloy type. The representative brand is UNS S31803 (22Cr-5Ni-3Mo-0.15N) and the PRE value is 32-33. Its corrosion resistance is between AISI316L (OOCr17Ni14Mo2) and 6% Mo+N austenitic stainless steel.
The third type belongs to high alloy type, which generally contains 25% Cr, molybdenum and nitrogen, and some also contain copper and tungsten. The standard grade is UNS S32550 (25Cr-6Ni-3Mo-2Cu-0.2N), and the PRE value is 38-39. The corrosion resistance of this kind of steel is higher than that of duplex stainless steel with 22% Cr.
The fourth type is super duplex stainless steel with high molybdenum and nitrogen. The standard grades are UNS S32750 (25Cr-7Ni-3.7Mo-0.3N), and some contain tungsten and copper. The PRE value is more than 40. It can be used in harsh medium conditions. It has good corrosion resistance and mechanical properties, and can be comparable to super austenitic stainless steel. 

III. Application of Duplex Stainless Steel

Duplex stainless steel is widely used in various fields because of its unique advantages:

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Pulp and paper industry: the first applications to use duplex stainless steels in the 1930’s was the sulfite paper industry. Duplex stainless steel is used currently by the pulp and paper industry for bleaching equipment, digesters, chip storage tanks, black and white liquor storage tanks, and suction roll shells. Duplex stainless steel has replaced austenitic stainless steel and carbon steel as the higher strength and superior corrosion resistance of duplex stainless steel allows for thinner plate to be used for the same pressure rating.
Fabrication with thinner plate results in lower overall material costs and less welding time, along with lower shipping and handling costs.
Chemical Processing Industry: chemical Processing Industry covers a wide range of work conditions are also more complex. Storage tanks for industrial wet-process phosphoric acid are usually made of 316L or 317L type Austenitic stainless steel with thick walls. The strength of 2205 duplex stainless steel is almost double that of 316L and 317L, and the wall thickness can be reduced, thus the importance and cost of storage tank can be reduced. At the same time, 2205 has better local corrosion resistance than austenitic stainless steel in industrial sulphuric acid environment, especially in the presence of chloride ions.
Food and drink industry: in the food and drink industries too, lean duplex stainless steel is proving its worth.
The material is being used for two projects in Spain, a food storage depot and a wine storage depot. In the Port of Barcelona Emypro SA constructed food storage tanks entirely from S32101 as a replacement for Types EN 304/304L. The wine storage depot, built by Spanish tank builder Martinez Sole for Garcia Carrión in Daimiel in the south of Spain, is the first to use duplex stainless steel: S32101 and 2304 were used in the construction of the roof and uppermost level of all new tanks, as a lower cost alternative to Types 304/304L.
Transportation: Duplex stainless steel has great advantages in making chemical tankers due to its high strength and excellent corrosion resistance. It reduces the importance of the ship and the fuel consumption. In this respect, the most used is the chromium duplex stainless steel of 22%. At the same time, it can meet the corrosion resistance of the materials needed for the goods. (Key Points for Production Preparedness of Duplex Stainless Steel Chemicals Ship)

Construction: In coastal areas, the air is filled with ocean atmosphere evaporated from sea water, in which chloride ion concentration is much higher than that of inland air. Therefore, seawater corrosion resistant materials are needed. The corrosion resistance of duplex stainless steel has this advantage, at the same time, its high strength can also reduce weight. At present, many offshore oil platforms use duplex stainless steel to manufacture explosion-proof walls.

Desalination: desalination presents one of the most severe tests to materials owing to the high-chloride, high-temperature corrosive process environment. The history of de- salination is largely a history of materials development, as desalination equipment suppliers and customers seek to balance the needs for corrosion resistance with needs to keep investment costs under control to make desalination projects affordable. In the early days of desalina- tion, the evaporators of both multi-stage flash (MSF) and multi-effect (MED) desalination plants were manufactured using mild steel. At a later stage, MSF evaporators were typically clad with 316L austenitic stainless steel. MED chambers were first coated with epoxy and next clad with stainless.
The benefits of duplex stainless steel for this application are high strength – double that of conventional austenitic grades – combined with high corrosion resistance. As a result, duplex stainless steel evaporators can be built with thinner plates, requiring less material and less welding. Further benefits include easier handling and less overall environmental impact.
The breakthrough for the duplex stainless steel concept came in 2003, when grade 2205 duplex stainless steel was selected for solid-duplex evaporators to be installed in the Melittah MSF plant and the Zuara MED plant in Libya.
The next stage in the duplex stainless steel desalination evolution was initiated in 2004 when two different types of duplex stainless steel were used in the structures of evaporators – applying the highly corrosion-resistant 2205 for parts exposed to the most hostile conditions, and 2304 for parts exposed to less hostile conditions.
Three MSF plants were constructed using this dual duplex concept, with a combination of 2205 and UNS S32101: Taweelah B (Abu Dhabi, 69.2 MIGD capacity), Jebel Ali L2 (Dubai, 55 MIGD) and Ras Abu Fontas B2 (Qatar, 30 MIGD).
Oil and gas: in oil and gas, duplex stainless steel has played a crucial role in helping to with- stand aggressive conditions. This is due to its strength and pitting and crevice corrosion resistance, which is superior to that of standard austenitic alloys, with PREN often exceeding 40.
The main applications for duplex stainless steels are flow lines, process piping systems and equipment like separators, scrubbers and pumps. Subsea the materials are used in downhole production tubing, piping and manifolds, Christmas tree components, flowlines and duplex stainless steel pipelines transporting corrosive oil and gas.
Super duplex stainless steels (25% chromium) are used for their high strength, so they are often used for bar, forgings, castings, sheet, plate, tube, and fasteners. Super duplex stainless steels also have excellent fatigue resistance and galvanic compatibility with other high alloy stain- less steels.
Umbilicals are used for controlling wellhead functions using hydraulic lines and can also be used for chemical injection. Since steel umbilicals were introduced to the market, duplex stainless steels have been the most commonly used material. In recent years there has been a trend to explore fields at deeper sea depths and longer umbilicals are required. Increasing the strength of the material decreases the weight of the umbilical, which enables longer lengths. Umbilcals are now being used in warmer water, and new concepts are developing where a riser is introduced in the umbilical. These trends demand increased corrosion resistance and mechanical strength. New hyper duplex stainless steels with better corrosion resistance and higher strength than super duplex stainless steel have been developed for use in umbilicals.
Architecture: Duplex stainless steel continues to play an important role in the construction of bridges, wherever corrosion and saline conditions combine with the need for high load-bearing strength. Two recent ex-amples, both from Asia, are Hong Kong’s Stonecutters Bridge and Singapore’s Helix Bridge, both of which use duplex grade 2205 stainless steel. For the Stonecutters Bridge, 2000 tons of 2205 duplex plate and pipe were used in 2006. The skin segments were finished by a fabricator in China from customized plates. The plates were polished and shot-peened to provide the optimum level of reflection during both day and night.
In addition, the Helix Bridge uses 570 tons of duplex stainless steel. The bridge’s stunning design comprises two spiralling tubular stainless steel members re- sembling the structure of DNA, and the double-helix and support structures use duplex 2205 pipes and plates respectively. The stainless steel surfaces provide night time illumination by reflecting lights programmed to enhance the design.
The world’s largest stainless steel roof at the New Doha International Airport in Qatar is constructed of a molybdenum- grade lean duplex stainless steel (S32003). The terminal’s most striking feature is its undulating roof, said to be the largest stainless steel roof in the world. The area of the terminal roof is approximately 195,000 square meters (2.1 million square feet) and used approximately 1600 metric tonnes (3.5 million pounds) of duplex stainless steel. Several factors had to be taken into account when selecting the stainless steel grade. The most important of these was the airport’s close proximity to the sea. The roof had to resist not only the heat and humidity found in the Middle East, but it also had to withstand salt corrosion. Other factors in the selection included cost and a favorable strength- to-weight ratio for duplex stainless steel compared to other grades.

Petrochemical industry: The corrosive environment of petrochemical industry and chemical industry is characterized by high reaction temperature, high or medium concentration of chloride in medium, which easily induces stress corrosion cracking of stainless steel. Therefore, not only duplex stainless steel but also super duplex stainless steel are needed in this field.
Oil refining industry is one of the areas where duplex stainless steel is widely used. It is mainly used in atmospheric and vacuum distillation, catalytic cracking hydrodesulfurization and other devices, and has been used at home and abroad. In addition, the use of duplex stainless steel in the production of acid gas and oil is gradually increasing, mainly used as production pipe lining, offshore and offshore pipeline systems and heat exchangers.

In addition, duplex stainless steel has been successfully applied to heat exchangers, hot water pipes and water heaters for wastewater treatment.

IVResearch Progress of Duplex Stainless Steel

Research Progress of Duplex Stainless Steel Abroad
The development of duplex stainless steel began in the 1930s. In 1936, the first duplex stainless steel patent was granted in France, and duplex stainless steel has been developed for three generations.
The first generation of duplex stainless steel is represented by 3RE60 in Sweden and AISI329 in the United States. 3RE60 is a duplex stainless steel specially developed to improve the resistance to chloride stress corrosion cracking. AISI329 duplex stainless steel is widely used in heat exchanger pipes of nitric acid plants. The first generation duplex stainless steel has good performance characteristics, but it has limitations in welding state. The heat affected zone of weld has low toughness due to excessive ferrite, and its corrosion resistance is lower than that of base metal. These limitations limit the application of the first generation duplex stainless steel to some specific applications in the non-welded state.
The invention of argon-oxygen decarbonization, a refining process for stainless steel 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 alloying element nitrogen. Nitrogen addition in duplex stainless steel can make the toughness and corrosion resistance of HAZ in welding state close to that of base metal. Nitrogen also reduces the formation rate of harmful intermetallic phase. Nitrogen-containing duplex stainless steel is called the second generation duplex stainless steel. 2205 is the representative steel of the second generation dual phase steel and is widely used in offshore petroleum platforms, chemical industry, paper making and other fields.
Super duplex stainless steel developed in the late 1980s belongs to the third generation of duplex stainless steel. Its representative grades are SAF2507, UR52N, Zeron100, etc. This kind of steel is characterized by low carbon content, high molybdenum content and high nitrogen content. This kind of steel has excellent pitting resistance. The equivalent of pitting corrosion) is greater than 40.
From the current level of research and production, Europe and the United States are leading in the R&D and production of duplex stainless steel as well as user recognition. The representative companies are Outokumpu, Sandvik in Sweden, KA and KL in the United States. In Asia, Japan and Korea are the main producers of duplex stainless steel. There is a certain gap between the production level of steel grades and that of Europe and America. Taking 2205 as an example, the main brands produced in Japan and Korea are S31803, while those produced in Europe and America are S32205.
Research Progress of Duplex Stainless Steel in China
The research of duplex stainless steel in China began in the mid-1970s. The research work of 00Cr18Ni5Mo3Si2 developed by Beijing Iron and Steel Research Institute was the earliest. It has been incorporated into the national standard. Baosteel Special Steel Co. has produced 2507 super duplex stainless steel pipes. Baosteel Pugang has produced 2205 sheets. However, the batch production is very small and the yield is low. It is mainly used for special purposes. At present, Taigang and Baosteel are able to supply commodity materials in China. Tisco began to develop 2205 duplex stainless steel in the late 1990s, and introduced its products to the market in 2005. The 2205 produced by Tisco meets the standard requirement of S31803. The patent of TISCO discloses a low nickel duplex stainless steel, which has the advantages of low cost and high strength. Baosteel No. 1 Steel Company also began to develop Cr22 duplex stainless steel in 2006. Now it can produce 4-8mm coil and 14-30mm medium plate 2205. Baosteel’s patent discloses a high nitrogen and low nickel duplex stainless steel, which has excellent room temperature impact and corrosion resistance, and can be widely used in coastal construction, petrochemical industry and other fields. It is worth noting that some small and medium-sized stainless steel enterprises have begun to study duplex stainless steel.
Future Development Direction of Duplex Stainless Steel
In recent years, duplex stainless steel has shown a two-way development trend with the rising and volatility of Ni price. First, to give full play to the advantages of resource saving of duplex stainless steel and develop economic duplex stainless steel such as 2101. Its development direction is to replace traditional 300 series austenitic stainless steel. Its design idea is to replace precious metals such as Ni and Mo with Mn and N elements. Second. It is to give full play to the characteristics of high strength and good corrosion resistance of duplex stainless steel, to develop super duplex stainless steel represented by 2507 and 2906, to partly replace super austenitic stainless steel 904L, 254Mo, etc.
From the development of duplex stainless steel at home and abroad, it can be seen that duplex stainless steel is a resource-saving and high-performance stainless steel product. Its production and application conform to the direction of future development of stainless steel. At the same time, duplex stainless steel is a high-tech, high value-added product, its development and production not only reflects the technical level of stainless steel production enterprises, but also can create more economic benefits for enterprises. It can be predicted that the proportion of duplex stainless steel will be further expanded in the future, and the development of duplex stainless steel has a bright future.

V. Development Trend of Duplex Stainless Steel

Economic Duplex Stainless Steel
There are three kinds of mature new steel developed abroad: one is developed by Armco nitronic company of the United States and has been incorporated into ASTM a240 / a240m steel plate standard, the brand is unss32001, the enterprise code is 19d, which is a new steel that is not easy to produce δ phase, and has been used in deep-sea pipeline cable, automobile frame, etc. The other was developed by Outokumpu in Finland in 2002. The company’s name is LDX 2101. It has been incorporated into the United States standard in 2006 and its name is UNSS32101. It can be used to manufacture process equipment for moderately corrosive environment, such as white liquor tanks in paper mills. Its potential use is very wide. In recent years, special attention has been paid to the development of steel grades for infrastructure, and they have been successfully used in the construction of bridges, etc. These two steels are substituted for Ni by Mn and N, which can reduce the content of Ni and Cr. Their corrosion resistance is equal to 304LH. Because they do not contain Mo, they are cheap, but they are not suitable for offshore structures. The third kind of AL2003 steel, developed by Allegheny Technologies Company of the United States, has been incorporated into the United States standard. Its nickel content is 3.5%, which is higher than the first two steels, and contains 1.7% Mo. It can be used in high-pressure pipeline system for submarine transportation of sulfur-free or light sulfur-containing oil and gas at a depth of 1200 M.
Considering the domestic resource situation, it is considered that this kind of steel has development value, and it needs economic dual-phase steel with wide application prospect in medium corrosion environment. At present, the development of LDX2101-like steel is being carried out, and further research on composition optimization, welding process and properties is needed.
Super and Duplex Stainless Steel
SAF2507 steel developed in Sweden is the most widely used steel in super duplex stainless steel. It has been incorporated into the standards of many countries. Its phase balance is good, and it is easier to master the production process in the same kind of steel. It has excellent local corrosion resistance especially in high chloride environment. It is often used in seawater heat exchangers, pipelines and cables of submarine oil fields, seawater desalination, flue gas desulfurization and other devices. Zeron 100 steel containing W and Cu has been developed in the UK. It has been successfully used in seawater jet pumps and lifting pumps for a long time because of its excellent wear resistance and corrosion resistance. From a technical point of view: offshore industry is the most meaningful place to use super duplex stainless steel. However, in order to meet the requirements of the wellhead control system for improved oil and gas recovery methods for higher corrosion resistance and the needs of temporary pipelines and pipeline cables in deep seabed, the existing steel grades have been inadequate in strength and corrosion resistance. Swedish Sandvik Company has designed a series of super duplex steel. Stainless steel SAF2906, SAF2707HD and SAF3207HD have super high strength up to 1000 MPa and excellent corrosion resistance.
At the same time, Ferralium 225-SD50 steel with copper addition, developed by Langley Alloys Co., USA, not only improves its pitting and crevice corrosion resistance in seawater, but also increases its strength by 10% compared with other super duplex stainless steels.
In addition, a new SAFUREX steel with 29% Cr and 0.4% N for Stamicarbon urea stripper has recently been developed for special purposes, which can replace 2RE69 austenitic steel. In order to treat chloride food tank, Japan has also developed NARDP-3W steel containing 2% W, and DP28WTM steel with better corrosion resistance, mechanical properties, formability and weldability.

VI. Conclusion

After three generations of development and improvement, duplex stainless steel has replaced austenitic stainless steel in production, processing, manufacturing and application. It has won the favor of users because of its superior mechanical and corrosion resistance, and has become an excellent corrosion-resistant engineering material which can save both weight and investment. In recent years, with the entry of super duplex stainless steel into the market, conditions have been created for expanding the selection of duplex stainless steel and the development of new steel grades.

Source: China Duplex Stainless Steel Pipe Fittings Manufacturer – Yaang Pipe Industry Co., Limited (www.ugsteelmill.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

If you want to have more information about the article or you want to share your opinion with us, contact us at sales@ugsteelmill.com

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application and development of duplex stainless steel - Application and Development of Duplex Stainless Steel
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Application and Development of Duplex Stainless Steel
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In recent years, duplex stainless steel has shown a two-way development trend with the rising and volatility of Ni price.
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