Duplex Steel F55 (UNS S32760): Product Introduction
Duplex stainless steel F55, also known as UNS S32760, is a highly corrosion-resistant alloy with superior mechanical properties. This article provides a comprehensive introduction to Duplex Steel F55 (UNS S32760), covering its chemical composition, mechanical properties, performance at different temperatures, industry applications, shapes and sizes, production standards, welding and processing capabilities, advantages and disadvantages, and a comparison with similar alloys.
Chemical Composition
Duplex Steel F55 (UNS S32760) has a well-balanced chemical composition that enhances its corrosion resistance and mechanical strength:
| Element | Composition (%) |
|---|---|
| Chromium (Cr) | 24.0 – 26.0 |
| Nickel (Ni) | 6.0 – 8.0 |
| Molybdenum (Mo) | 3.0 – 4.0 |
| Copper (Cu) | 0.5 – 1.0 |
| Tungsten (W) | 0.5 – 1.0 |
| Nitrogen (N) | 0.20 – 0.30 |
| Carbon (C) | 0.030 max |
| Silicon (Si) | 1.00 max |
| Manganese (Mn) | 1.00 max |
| Phosphorus (P) | 0.030 max |
| Sulfur (S) | 0.010 max |
Mechanical Properties
Duplex Steel F55 (UNS S32760) exhibits excellent mechanical properties suitable for demanding applications:
| Property | Value |
|---|---|
| Tensile Strength, ksi (MPa) | 109 min (750 min) |
| Yield Strength (0.2% offset), ksi (MPa) | 80 min (550 min) |
| Elongation (% in 2 inches) | 25 min |
| Hardness, Rockwell C (HRC) | 32 max |
Performance Characteristics
Duplex Steel F55 (UNS S32760) offers superior performance across various conditions:
- Corrosion Resistance: Excellent resistance to chloride-induced stress corrosion cracking (SCC), pitting, and crevice corrosion in aggressive environments, such as seawater and chemical processing.
- Strength: Higher strength compared to standard duplex stainless steels, making it suitable for structural applications requiring high mechanical strength.
- Weldability: Good weldability with appropriate filler materials and techniques, ensuring ease of fabrication and repair.
Industry Applications
Duplex Steel F55 (UNS S32760) finds extensive use in industries requiring robust corrosion resistance and high strength:
| Industry Sector | Applications |
|---|---|
| Oil and Gas | Offshore and subsea equipment, including pipelines, risers, and subsea umbilicals. |
| Chemical Processing | Heat exchangers, pressure vessels, and tanks handling aggressive chemicals. |
| Marine | Seawater desalination plants, marine structural components, and offshore platforms. |
Shapes and Sizes
Duplex Steel F55 (UNS S32760) is available in various forms and sizes to meet specific application needs:
- Forms: Sheets, plates, bars, tubes, pipes, and fittings.
- Sizes: Thickness ranging from 0.5 mm to 50 mm for plates, and diameter ranging from 6 mm to 300 mm for round bars.
Production Standards
Duplex Steel F55 (UNS S32760) adheres to international production standards ensuring quality and reliability:
| Product Form | Shapes Available | Sizes Available | Production Standards |
|---|---|---|---|
| Plates/Sheets | Sheets, Plates | Thickness: 0.5 mm – 50 mm | ASTM A240, EN 10088 |
| Bars/Rods | Round bars, Square bars | Diameter: 6 mm – 300 mm | ASTM A276, EN 10088 |
| Pipes/Tubes | Seamless, Welded | OD: 6 mm – 300 mm | ASTM A790, ASTM A789 |
Welding and Processing
Duplex Steel F55 (UNS S32760) offers good weldability and processing characteristics:
- Welding: Can be welded using standard methods like TIG, MIG, and submerged arc welding, with proper preheating and post-weld heat treatment to maintain corrosion resistance.
- Machinability: Generally lower than austenitic stainless steels, requiring slower speeds and more power for machining operations.
Advantages and Disadvantages
| Aspect | Details |
|---|---|
| Advantages | Exceptional corrosion resistance in aggressive environments, high strength, good weldability, suitable for a wide range of applications in marine, oil and gas, and chemical industries. |
| Disadvantages | Lower toughness compared to austenitic stainless steels, requires careful handling during welding and fabrication due to its dual-phase microstructure. |
Comparison with Similar Alloys
Duplex Steel F55 (UNS S32760) is often compared with other duplex stainless steels such as F51 (UNS S31803) and super duplex stainless steels like F53 (UNS S32750). Here’s a brief comparison:
| Alloy Type/Property | Duplex Steel F55 (UNS S32760) | Duplex Steel F51 (UNS S31803) | Super Duplex Steel F53 (UNS S32750) |
|---|---|---|---|
| Corrosion Resistance | Excellent resistance to chloride-induced corrosion including pitting and crevice corrosion. | Excellent resistance, slightly lower than F55 in aggressive chloride environments. | Enhanced resistance to pitting and crevice corrosion, particularly in seawater applications. |
| Strength | Highest strength among duplex steels, ideal for heavy-duty applications in harsh environments. | High strength with good toughness, suitable for general-purpose applications. | Higher strength compared to standard duplex steels, suitable for structural applications. |
| Applications | Offshore platforms, heat exchangers, and seawater handling systems. | Oil and gas, chemical processing, marine environments. | Similar applications with broader use in structural and architectural applications. |
This detailed article introduces Duplex Steel F55 (UNS S32760), highlighting its chemical composition, mechanical properties, performance characteristics, industry applications, available forms and sizes, production standards, welding and processing capabilities, as well as advantages, disadvantages, and a comparison with similar alloys. Engineers and professionals seeking durable materials for applications requiring corrosion resistance and high strength will find this information valuable for selecting the appropriate alloy to meet specific operational needs.