Products
Super Duplex Stainless Steel
Super duplex stainless steel is an advanced stainless steel alloy known for its high chromium, molybdenum, and nitrogen content, providing exceptional corrosion resistance, strength, and durability. It combines the best features of austenitic and ferritic stainless steels, making it ideal for extremely demanding applications, especially in harsh environments like marine, oil and gas, and chemical processing.
Super duplex stainless steel has a unique microstructure, which enhances its mechanical properties and resistance to various forms of corrosion, particularly in environments with high chloride content.
Key Characteristics of Super Duplex Stainless Steel
- Outstanding Corrosion Resistance
- Super duplex stainless steel offers superior resistance to pitting, crevice corrosion, and chloride stress corrosion cracking. This makes it highly reliable in saltwater, acidic, and other aggressive environments.
- High Mechanical Strength
- The yield strength of super duplex stainless steel is around twice that of austenitic stainless steel, such as 304 and 316. This allows for thinner, lighter components without compromising strength, reducing material and fabrication costs.
- Enhanced Fatigue Resistance
- With its dual-phase microstructure, super duplex stainless steel can withstand high-cycle fatigue, making it suitable for applications involving fluctuating stress.
- Good Weldability
- A super duplex can be welded, although it requires careful heat control and post-weld treatment to preserve its dual-phase microstructure and prevent embrittlement.
- Cost-Effective and Sustainable
- While super duplex stainless steel may have a higher initial cost, its strength and durability reduce long-term maintenance and replacement costs. Additionally, duplex materials are recyclable, contributing to sustainable practices.
Grades of Super Duplex Stainless Steel
- UNS S32750 (2507)
- The most common super duplex grade, S32750 has 25% chromium, 7% nickel, and around 3.5% molybdenum. This composition gives it exceptional corrosion resistance and strength, suitable for extremely corrosive environments.
- UNS S32760
- Known for additional alloying elements like tungsten and copper, S32760 offers even higher corrosion resistance and is used in the most severe environments, including offshore oil and gas and chemical processing.
- UNS S39274
- This grade has a similar composition to S32760 but includes nitrogen for extra strength and enhanced pitting resistance, ideal for applications involving high temperatures and pressure.
Applications of Super Duplex Stainless Steel
- Oil and Gas Industry: Super duplex stainless steel is widely used in offshore and subsea applications, including pipelines, valves, and manifolds, where exposure to seawater and corrosive substances is common.
- Chemical Processing: Suitable for handling aggressive chemicals, acids, and chlorides, super duplex is used in chemical storage tanks, heat exchangers, and reactors.
- Desalination Plants: Super duplex resists the high salinity and corrosive conditions in desalination facilities, especially in seawater intake and brine discharge sections.
- Marine Environments: Ideal for seawater applications, including shipbuilding, seawater cooling, and coastal structures.
- Pulp and Paper Industry: Resists chemicals used in pulping and bleaching, helping extend equipment life in paper processing plants.
Benefits of Super Duplex Stainless Steel
- Enhanced Service Life: The super duplex’s high corrosion resistance and strength provide longer-lasting performance, even in harsh conditions.
- Reduced Maintenance Costs: With increased durability and minimal risk of corrosion, super duplex requires less frequent maintenance and replacement.
- Lightweight Design: The high strength-to-weight ratio allows for reduced material thickness, saving weight and lowering costs without sacrificing integrity.
- Sustainability: Fully recyclable, super duplex is an eco-friendly material that aligns with sustainable manufacturing and industrial practices.
Properties of Super Duplex Stainless Steel
- High Chromium Content: Improves oxidation resistance and forms a protective passive layer on the surface.
- Molybdenum and Nitrogen Additions: Enhance resistance to pitting, crevice corrosion, and other localized corrosion forms.
- Low Thermal Expansion: Similar to carbon steel, the super duplex offers low thermal expansion, making it ideal for temperature-sensitive applications.
- Increased Tensile and Yield Strength: Provides structural integrity in high-stress applications, allowing the use of thinner material.
Standards and Specifications
Super duplex stainless steels adhere to stringent manufacturing standards to ensure performance and reliability:
- ASTM A790: Specification for super duplex seamless and welded pipes.
- ASTM A182: Forged fittings and flanges for high-stress applications.
- ASME B16.9 and B16.5: Standardized dimensions for fittings and flanges.
- NACE MR0175/ISO 15156: Certification for use in sour (hydrogen sulfide-rich) environments, common in oil and gas.
Standards and Specifications
Super duplex stainless steels adhere to stringent manufacturing standards to ensure performance and reliability:
- ASTM A790: Specification for super duplex seamless and welded pipes.
- ASTM A182: Forged fittings and flanges for high-stress applications.
- ASME B16.9 and B16.5: Standardized dimensions for fittings and flanges.
- NACE MR0175/ISO 15156: Certification for use in sour (hydrogen sulfide-rich) environments, common in oil and gas.
FAQs
Products
Industry We Serve
- Oil & Gas industries
- Chemical process industries
- Pump and valve in high pressure component
- Food industries
- Pulp and paper industry
- Aerospace industry
- Power plant
- Mechanical component
- Sugar industry
- Cement industry