A Guide to Duplex Stainless Steel: Advantages, Applications, and Grades Compared
Duplex steel is a specialized family of stainless steel grades which exhibit two distinct metallurgical phases within the metal’s micrograin structure – hence the name duplex. This unique metallurgical property provides duplex stainless steel with various advantages when compared to other alloys.
Duplex Stainless Steel Metallurgy Explained
As mentioned above, duplex stainless steels exhibit a two-phase metallurgical microstructure with a nearly equal composition of austenite and ferrite material. This allows manufacturers to take advantage of the benefits of both metallurgical families while minimizing any drawbacks.
For example, elements such as chromium, molybdenum and nitrogen can be increased in concentration for applications which demand generally enhanced corrosion resistance (e.g. for the oil and gas processing industry), while nickel can be increased in concentration specifically for chloride pitting and corrosion (e.g. for water processing and desalination plants).
Essentially, an optimal material solution can be achieved for a wide range of industrial fabrication projects through materials science and engineering.
Duplex Stainless Steel Grades Compared: Advantages and Applications
An Overview of 2205 Duplex Stainless Steel
2205 duplex contains approximately 40 – 50% ferrite once the metal is annealed. A major benefit of 2205 duplex is its high resistance to chloride corrosion and stress cracking – superior to the common alternative 316L stainless steel. 2205 duplex also offers good resistance to sulfide corrosion as well as general corrosion resistance.
Common Manufacturing Applications for 2205 Duplex Stainless Steel
- Chemical processing equipment
- Pulp mill processing equipment
- Food and beverage industry process equipment
- Flue gas desulfurization (FGD) scrubber systems
- Oil and gas industry equipment including piping vessels
- Industrial heat exchangers for various applications
An Overview of 2507 Duplex Stainless Steel
2507 duplex stainless steel offers extremely high strength combined with excellent corrosion resistance. Designated as a super duplex stainless steel, the composition of 2507 duplex is 25% chromium, 7% nickel alloy, and 4% molybdenum. The high nickel composition provides the material with exceptional resistance to chloride pitting and crevice corrosion in seawater applications.
Common Manufacturing Applications for 2507 Duplex Stainless Steel
- Desalination plant processing equipment
- Chemical manufacturing and processing equipment
- Various maritime and marine applications
- Flue gas desulfurization (FGD) scrubber systems
- Pulp and paper mill processing equipment
- Oil and gas pipelines and various processing equipment
ZERON 100 was uniquely developed for use in pump applications as a seawater-resistant material. However, the material’s exceptional strength and general corrosion resistance have enabled a much more widespread demand and usage – from power generation and chemical manufacturing to pharmaceutical processing applications. ZERON 100 duplex stainless steel also offers excellent resistance to sulfuric acid corrosion and better corrosion fatigue than most austenitic stainless steel grades.
Common Manufacturing Applications for ZERON 100 Duplex Stainless Steel
- Seawater processing and desalination plants
- Various power generation applications
- Oil and gas industry equipment
- Flue gas desulfurization (FGD) scrubber systems
- Industrial heat Exchangers
- Pulp and paper mill processing equipment
- Chemical manufacturing and processing
- Pharmaceutical processing applications
- Mining and various metallurgical industries
- Maritime and marine applications
An Overview of LDX 2101 Duplex Stainless Steel
LDX 2101 is a lean duplex stainless steel that can be comparable in price to 304/304L and 316/316L stainless steels. At the same time, the metal’s duplex structure combined with a high nitrogen content provide significantly higher strength. Because of this, a lighter gauge of LDX 2101 can often be used for many industrial manufacturing projects, requiring less material and reducing the overall weight of the fabricated components. LDX 2101 provides high strength combined with high resistance to chloride corrosion and stress cracking, as well as good fatigue strength combined with good machinability.
Common Manufacturing Applications for LDX 2101 Duplex Stainless Steel
- Water and wastewater processing equipment
- Chemical processing equipment
- Industrial fluid mixers and agitators
- Pulp and paper mill processing equipment
- Various architectural equipment
