AISI 2507 Super-Duplex Stainless Steel: Propriétés, Fabrication & Applications Guide

AISI 2507 super-duplex stainless steel is the gold standard for extreme corrosion resistance and high strength. Son unique2507 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. Ce guide décompose ses spécifications clés, performance, and real-world uses to help you select it with confidence.

1. Aperçu du matériel & Spécifications clés

Understanding 2507’s composition and standards is critical to unlocking its full potential. Vous trouverez ci-dessous une ventilation claire de ses propriétés essentielles.

Composition chimique & Normes

Le2507 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 (Système de numérotation unifiée)
• 2507 DANS 1.4410 équivalent (Norme européenne pour les performances de correspondance)
• 2507 ASTM A240 / 2507 ASME SA-240 (pour les assiettes, feuilles, et les bandes)

Physique & Propriétés mécaniques

2507 delivers exceptional strength—far higher than standard duplex or austenitic alloys. Des mesures clés sont organisées dans le tableau ci-dessous:

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. Résistance à la corrosion & Performance environnementale

2507’s biggest advantage is its industry-leading corrosion resistance. Its2507 PREN 41–45 (Nombre équivalent de résistance aux piqûres) is far higher than 2205’s PREN of 35–40, making it nearly immune to pitting, crevice corrosion, and stress cracking in harsh fluids.

Traits clés résistants à la corrosion

• Piqûres & Crevice Corrosion: It has unmatched 2507 pitting corrosion resistance and a high 2507 crevice corrosion threshold—even in tight gaps (Par exemple, 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 normes, resisting 2507 sulfide stress cracking in oil wells with high hydrogen sulfide (H₂S) levels.
• Résistance chimique: 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 contre 2205 comparaison de corrosion: A Saudi desalination plant tested both alloys—2205 tubes showed pitting after 5 années, alors que2507 taux de corrosion d'eau de mer (≤0.005 mm/year) kept 2507 tubes operational for 15+ années.

3. À haute température & Low-Temperature Properties

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

High-Temperature Traits

• Force & Oxydation: It maintains 2507 high-temperature strength jusqu'à 300 ° C, avec 2507 résistance à l'oxydation jusqu'à 300 ° C (suitable for warm chemical processes like acid evaporation). Le 2507 continuous service temperature est 300 °C—beyond this, avoid prolonged exposure to prevent sigma phase formation.
• Résistance au fluage: 2507 Données de rupture de fluage shows it can last 10,000+ des heures de 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, avec 2507 impact energy at -50 ° C of ≥45 J (no brittle fracture). Its 2507 cryogenic ductility also makes it suitable for Arctic offshore projects (Par exemple, subsea pipelines in -40 °C conditions).

Une étude de cas: A U.S. geothermal plant used2507 Tubes d'échangeur de chaleur (opérant à 280 ° C). Après 8 années, no corrosion or creep deformation occurred—unlike the previous 2205 tubes that failed every 3 années.

4. Traitement thermique & 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.

Processus de traitement thermique essentiels

• Recuit de solution: Heat to 1025–1125 °C, tenir 30 à 60 minutes, then perform a 2507 rapid water quench (critical to prevent phase formation). This step restores the balanced microstructure and dissolves unwanted carbides.
• Travail chaud: Utiliser 1150–1000 °C as the 2507 gamme de travail à chaud for forging or rolling. This keeps the material ductile and preserves the ferrite-austenite balance.
• Soulagement résiduel du stress: Heat to 400–450 °C to reduce stresses from welding or forming. Avoid 475 ° C (le 2507 embrittlement at 475 ° C température) to prevent alpha-prime embrittlement.

Contrôle de la microstructure

• 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 et 2507 chi phase precipitation accelerate in this range, making the material brittle.

5. Soudage, Fabrication & Directives d'usinage

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

Conseils de soudage

• Consommables: Utiliser 2507 welding consumables 2509 / ER2594 (Pour le soudage Tig / Me)—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: Utiliser 2507 root gas purge 99.99 % N₂ + 5 % H₂ to ensure full austenite formation in the weld root. Après le soudage, perform 2507 post-weld cleaning passivation (pickling with nitric acid) to remove scale and restore corrosion resistance.

Usinage & Formation

• Vitesses & Aliments: 2507 Vitesses et flux d'usinage should be 15–20% lower than 2205. Utiliser 2507 La vie de l'outil avec du carbure enduit (TiAlN or diamond coatings work best—they resist wear from the alloy’s high strength).
• Formabilité: 2507 formability limits are moderate—cold bending is possible for thin sections, but avoid excessive strain (anneal after heavy forming to restore toughness). Utiliser 2507 techniques de contrôle de la distorsion (Par exemple, serrage pendant le soudage, refroidissement lent) to keep parts true to size.

6. Formulaires de produit, Tailles & Chaîne d'approvisionnement

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

Formulaires de produit communs

• Assiettes & Feuilles: 2507 super-duplex plate thickness chart ranges from 3 mm à 200 MM; 2507 sheet gauge sizes (16 évaluer 1/2 pouce) are ideal for chemical vessel liners.
• Tuyaux & Tubes: 2507 seamless pipe ASTM A790 (for high-pressure offshore flowlines) et 2507 welded pipe ASTM A928 (for low-pressure desalination lines).
• Bars & Raccords: 2507 Bars de la barre ronde (10 mm à 300 diamètre mm), 2507 tailles d'angle (20×20 mm à 100×100 MM), et 2507 Grades de tige filetés (Grade 1 for general use, Grade 2 for high-stress applications).
• Formulaires de spécialité: 2507 Largeurs de fente de bobine (10 mm à 1250 MM), 2507 Fournisseurs à barres creuses (Pour les pièces légères), 2507 pièces de redoutage personnalisées (Par exemple, corps de valve), et 2507 clad plate suppliers (for cost-effective large structures like FGD towers).

Conseils de chaîne d'approvisionnement

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. Applications de l'industrie & Études de cas

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

• Offshore & Marin: 2507 offshore flowlines, 2507 subsea pipelines, et 2507 chemical injection lines (resist seawater, H₂S, and high pressure).
• Water Treatment: 2507 desalination high-pressure piping (poignées 80+ bar pressure and high chlorides).
• Pouvoir & Industriel: 2507 FGD absorber towers (remove sulfur from power plant exhausts) et 2507 Tubes d'échangeur de chaleur (for acid and geothermal applications).
• Pulp & Papier: 2507 pulp & paper digesters (resist chlorine-based bleaches and high temperatures).

Un vrai exemple: A Brazilian oil company replaced 2205 avec 2507 for subsea wellheads—2507 sulfide stress cracking resistance eliminated wellhead failures, Réduction des coûts d'entretien de 90% and extending service life from 7 à 20 années.

Perspective de la technologie Yigu

À la technologie Yigu, Nous recommandons 2507 for clients needing extreme corrosion resistance + forte résistance. Nous achetons2507 ASTM A240 plaques et2507 seamless pipe ASTM A790 des moulins certifiés, ensuring PREN 41–45 and ferrite content 35–55%. For offshore/sour service clients, we provide NACE MR0175 testing and welding support (en utilisant2509/ER2594 consumables). Alors que 2507 coûte plus que 2205, its 2x longer lifespan and lower maintenance make it cost-effective for the harshest projects.

FAQ

1. When should I choose 2507 sur 2205?
   Choisir 2507 if your project involves high chlorides (>10,000 ppm), sour service (H₂S), or high pressure (>300 bar). Its PREN 41–45 et sulfide stress cracking resistance outperform 2205. Utiliser 2205 for milder conditions (Par exemple, low-pressure seawater) to save cost.
2. Peut 2507 be used at temperatures above 300 ° C?
   Avoid prolonged use above 300 ° C (c'est continuous service temperature). At 300–500 °C, 2507 Formation de phase Sigma et alpha-prime embrittlement occur, reducing toughness. Pour 300 °C+ applications, choose 347H (high-temperature strength) or 904L (résistance à la corrosion).
3. What’s critical for welding 2507?
   Three key steps: Utiliser 2507 welding consumables 2509/ER2594, control heat input 0.5–1.5 kJ/mm et 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.