AISI 2507 Aço inoxidável superduplex: Propriedades, Fabricação & Guia de aplicações

AISI 2507 o aço inoxidável superduplex é o padrão ouro para extrema resistência à corrosão e alta resistência. É único2507 ferrite-austenite balance 50-50 microstructure and ultra-high2507 PREN ≥ 40 make it ideal for the harshest environments—from deep-sea oil rigs to chemical processing plants. Este guia detalha suas principais especificações, desempenho, and real-world uses to help you select it with confidence.

1. Material Overview & Key Specifications

Understanding 2507’s composition and standards is critical to unlocking its full potential. Below is a clear breakdown of its essential properties.

Composição Química & Padrões

O2507 super-duplex composition is engineered for strength and corrosion resistance: 24–26% chromium, 6–8% nickel, 3–5% molybdenum, and 0.24–0.32% nitrogen. These elements create its balanced microstructure and high PREN. It adheres to global standards:

• 2507 UNS S32750 (Unified Numbering System)
• 2507 EM 1.4410 equivalente (European standard for matching performance)
• 2507 ASTM A240 / 2507 ASME SA-240 (for plates, folhas, and strips)

Physical & Propriedades Mecânicas

2507 delivers exceptional strength—far higher than standard duplex or austenitic alloys. Key metrics are organized in the table below:

A Norwegian offshore company uses2507 ASTM A240 plates for subsea manifolds—they rely on the 550 MPa yield strength to handle 400 bar deep-sea pressure and corrosive seawater.

2. Resistência à corrosão & Environmental Performance

2507’s biggest advantage is its industry-leading corrosion resistance. Isso é2507 PREN 41–45 (Pitting Resistance Equivalent Number) is far higher than 2205’s PREN of 35–40, making it nearly immune to pitting, crevice corrosion, and stress cracking in harsh fluids.

Key Corrosion-Resistant Traits

• Pitting & Crevice Corrosion: It has unmatched 2507 pitting corrosion resistance and a high 2507 crevice corrosion threshold—even in tight gaps (por exemplo, heat exchanger gaskets) exposed to 60 °C seawater.
• Stress Corrosion Cracking: It offers 2507 chloride stress corrosion cracking immunity—critical for desalination plants and offshore pipelines where chloride levels exceed 10,000 ppm.
• Sour Service: It meets 2507 sour service NACE MR0175 / ISO 15156 padrões, resisting 2507 sulfide stress cracking in oil wells with high hydrogen sulfide (H₂S) levels.
• Resistência Química: It handles 2507 sulfuric acid resistance (resists 30% sulfuric acid up to 50 °C) and has higher 2507 hydrochloric acid limits than 2205 (tolerates dilute HCl up to 30 °C).

2507 contra 2205 corrosion comparison: A Saudi desalination plant tested both alloys—2205 tubes showed pitting after 5 anos, enquanto2507 seawater corrosion rate (≤0.005 mm/year) kept 2507 tubes operational for 15+ anos.

3. High-Temperature & Low-Temperature Properties

2507 performs well across a wide temperature range, though it’s optimized for moderate heat and cold environments.

High-Temperature Traits

• Força & Oxidação: It maintains 2507 resistência a altas temperaturas até 300 °C, com 2507 oxidation resistance up to 300 °C (suitable for warm chemical processes like acid evaporation). O 2507 continuous service temperature é 300 °C—beyond this, avoid prolonged exposure to prevent sigma phase formation.
• Resistência à fluência: 2507 creep rupture data shows it can last 10,000+ horas às 250 °C under 150 MPa stress, making it ideal for high-pressure heat exchanger tubes.

Low-Temperature Traits

• Toughness: It has excellent 2507 low-temperature toughness, com 2507 impact energy at -50 °C of ≥45 J (no brittle fracture). Isso é 2507 cryogenic ductility also makes it suitable for Arctic offshore projects (por exemplo, subsea pipelines in -40 °C conditions).

A case study: Um EUA. geothermal plant used2507 heat exchanger tubes (operating at 280 °C). Depois 8 anos, no corrosion or creep deformation occurred—unlike the previous 2205 tubes that failed every 3 anos.

4. Tratamento térmico & Microstructure Balance

Proper heat treatment is critical to maintaining 2507’s 50-50 ferrite-austenite balance and avoiding harmful phases like sigma, chi, or alpha-prime.

Essential Heat Treatment Processes

• Solution Annealing: Aqueça até 1025–1125 °C, hold for 30–60 minutes, then perform a 2507 rapid water quench (critical to prevent phase formation). This step restores the balanced microstructure and dissolves unwanted carbides.
• Hot Working: Usar 1150–1000 °C como o 2507 hot working range for forging or rolling. This keeps the material ductile and preserves the ferrite-austenite balance.
• Residual Stress Relief: Heat to 400–450 °C to reduce stresses from welding or forming. Avoid 475 °C (o 2507 embrittlement at 475 °C temperatura) to prevent alpha-prime embrittlement.

Microstructure Control

• Ferrite Content: Maintain 2507 ferrite content 35–55 % (tested via magnetic methods) to ensure strength and corrosion resistance.
• Phase Prevention: Avoid heating to 500–800 °C for long periods—2507 sigma phase formation kinetics e 2507 chi phase precipitation accelerate in this range, making the material brittle.

5. Soldagem, Fabricação & Machining Guidelines

Soldagem 2507 requires precise heat control to preserve its microstructure, but it’s workable with the right techniques and consumables.

Welding Tips

• Consumables: Usar 2507 welding consumables 2509 / ER2594 (for TIG/MIG welding)—these match 2507’s composition and maintain the ferrite-austenite balance in the weld.
• Heat Input & Interpass Temperature: Strictly control 2507 heat input 0.5–1.5 kJ/mm (lower than 2205’s 0.5–2.5 kJ/mm) and keep 2507 interpass temperature 100 °C max (prevents sigma phase).
• Root Gas Purge: Usar 2507 root gas purge 99.99 % N₂ + 5 % H₂ to ensure full austenite formation in the weld root. Depois de soldar, executar 2507 post-weld cleaning passivation (pickling with nitric acid) to remove scale and restore corrosion resistance.

Usinagem & Formando

• Speeds & Feeds: 2507 machining speeds and feeds should be 15–20% lower than 2205. Usar 2507 tool life with coated carbide (TiAlN or diamond coatings work best—they resist wear from the alloy’s high strength).
• Formabilidade: 2507 formability limits are moderate—cold bending is possible for thin sections, but avoid excessive strain (anneal after heavy forming to restore toughness). Usar 2507 distortion control techniques (por exemplo, clamping during welding, slow cooling) to keep parts true to size.

6. Product Forms, Sizes & Supply Chain

2507 is available in a wide range of forms to fit nearly any high-corrosion, high-strength project.

Common Product Forms

• Plates & Sheets: 2507 super-duplex plate thickness chart varia de 3 mm para 200 milímetros; 2507 sheet gauge sizes (16 gauge to 1/2 inch) are ideal for chemical vessel liners.
• Pipes & Tubes: 2507 seamless pipe ASTM A790 (for high-pressure offshore flowlines) e 2507 welded pipe ASTM A928 (for low-pressure desalination lines).
• Bars & Acessórios: 2507 round bar stock (10 mm para 300 mm de diâmetro), 2507 angle iron sizes (20×20 mm to 100×100 milímetros), e 2507 threaded rod grades (Nota 1 para uso geral, Nota 2 for high-stress applications).
• Specialty Forms: 2507 coil slit widths (10 mm para 1250 milímetros), 2507 hollow bar suppliers (for lightweight parts), 2507 custom forgings (por exemplo, corpos de válvula), e 2507 clad plate suppliers (for cost-effective large structures like FGD towers).

Supply Chain Tips

Work with global suppliers who stock2507 seamless pipe ASTM A790 and hold NACE MR0175 certification—these ensure compliance for sour service. For urgent offshore projects, prioritize suppliers with local inventory of common sizes to reduce lead times.

7. Aplicações Industriais & Estudos de caso

2507’s unbeatable strength and corrosion resistance make it a top choice for industries facing extreme conditions. Here are key use cases:

• Offshore & Marinho: 2507 offshore flowlines, 2507 dutos submarinos, e 2507 chemical injection lines (resist seawater, H₂S, and high pressure).
• Water Treatment: 2507 desalination high-pressure piping (alças 80+ bar pressure and high chlorides).
• Power & Industrial: 2507 FGD absorber towers (remove sulfur from power plant exhausts) e 2507 heat exchanger tubes (for acid and geothermal applications).
• Pulp & Paper: 2507 pulp & paper digesters (resist chlorine-based bleaches and high temperatures).

A real example: A Brazilian oil company replaced 2205 com 2507 for subsea wellheads—2507 sulfide stress cracking resistance eliminated wellhead failures, reduzindo custos de manutenção por 90% and extending service life from 7 para 20 anos.

Yigu Technology’s Perspective

Na tecnologia Yigu, nós recomendamos 2507 for clients needing extreme corrosion resistance + alta resistência. Nós fornecemos2507 ASTM A240 plates and2507 seamless pipe ASTM A790 from certified mills, ensuring PREN 41–45 and ferrite content 35–55%. For offshore/sour service clients, we provide NACE MR0175 testing and welding support (usando2509/ER2594 consumables). Enquanto 2507 costs more than 2205, its 2x longer lifespan and lower maintenance make it cost-effective for the harshest projects.

Perguntas frequentes

1. When should I choose 2507 sobre 2205?
   Escolher 2507 if your project involves high chlorides (>10,000 ppm), sour service (H₂S), or high pressure (>300 bar). Isso é PREN 41–45 e sulfide stress cracking resistance outperform 2205. Usar 2205 for milder conditions (por exemplo, low-pressure seawater) to save cost.
2. Can 2507 be used at temperatures above 300 °C?
   Avoid prolonged use above 300 °C (isso é continuous service temperature). At 300–500 °C, 2507 sigma phase formation e alpha-prime embrittlement occur, reducing toughness. Para 300 °C+ applications, choose 347H (resistência a altas temperaturas) or 904L (resistência à corrosão).
3. What’s critical for welding 2507?
   Three key steps: Usar 2507 welding consumables 2509/ER2594, controlar heat input 0.5–1.5 kJ/mm e interpass temperature 100 °C max, and purge the root with 99.99 % N₂ + 5 % H₂. Post-weld passivation is also required to restore corrosion resistance.