Duplex Steel
Key Features
● Strength:
○ Duplex stainless steel bars showcase exceptional hardness, making them the preferred choice for applications demanding unparalleled strength.
● Two-Phase Microstructure:
○ Termed "Duplex" due to their two-phase microstructure comprising grains of both ferritic and austenitic stainless steel. This unique structure contributes to their distinctive advantages.
PREN Values:
| Steel Grade | 1.4307 | 1.4404 | 904L | 1.4462 | 2205 |
| PREN | 18 | 24 | 34 | 31 | 3512 |
Physical and Mechanical Properties:
● Twice the Strength:
○ Duplex steel exhibits approximately twice the strength of regular austenitic or ferritic stainless steel, ensuring robust performance in diverse environments.
● Corrosion Resistance:
○ The corrosion resistance of duplex steel, influenced by its composition, surpasses that of traditional stainless steel. This property is crucial for longevity in various applications.
● Toughness and Ductility:
○ Duplex stainless steel outperforms ferritic grades in terms of toughness and ductility, providing a combination of durability and flexibility.
Mechanical Properties:
| Grade No. | Yield Strength (Rp 0.2%) (Min) | UTS (Mpa) (Min) | UTS (Mpa) (Max) | % Elongation (Min) | % Reduction Area (Min) | Hardness (BHN) (Max) |
| 1.4462 | 450 | 650 | 880 | 25 | - | 270 |
| UNS S31803 | 448 | 620 | - | 25 | - | 290 |
| UNS S32205 | 450 | 655 | - | 25 | - | 290 |
Chemical Composio:
| Standard | Grade | C % | Si % | Mn % | P% | S% | Cr% | Mo% | Ni% | Cu% | N2% |
| ASTM A 182:2018 | F-51 | 0.03 | 1 | 2 | 0.03 | 0.02 | 21-23 | 2.5-3.5 | 4.5-6.5 | - | 0.08-0.2 |
| ASTM A 182:2018 | F-60 | 0.03 | 1 | 2 | 0.03 | 0.02 | 22-23 | 3.0-3.5 | 4.5-6.5 | - | 0.14-0.2 |
| ASTM A 182:2018 | F-53 | 0.03 | 0.8 | 1.2 | 0.035 | 0.02 | 24-26 | 44990 | 6.0-8.0 | 0.5 | 0.24-0.32 |
| ASTM A 276:2017 | UNS S32205 | 0.03 | 1 | 2 | 0.03 | 0.02 | 22-23 | 3.0-3.5 | 4.5-6.5 | - | 0.14-0.2 |
| ASTM A 276:2017 | UNS S31803 | 0.03 | 1 | 2 | 0.03 | 0.02 | 21-23 | 2.5-3.5 | 4.5-6.5 | - | 0.08-0.20 |
| ASTM A 240:2018 | UNS S32750 | 0.03 | 0.8 | 1.2 | 0.035 | 0.02 | 24-26 | 44990 | 6.0-8.0 | 0.5 | 0.24-0.32 |
| Din EN 10088-3 : 2014 | 1.4462 | 0.03 | 1 | 2 | 0.035 | 0.015 | 21-23 | 2.5-3.5 | 4.5-6.5 | - | 0.1-0.22 |
| EN 10095 :1999 | 1.4821 | 0.1-0.2 | 0.8-1.5 | 2 | 0.04 | 0.015 | 24.5-26 | - | 3.5-5.5 | - | 0.11 |
| 5 | |||||||||||
| Super Duplex | 1.4302 | <0.05 | <1.4 | <1.9 | <0.025 | <0.015 | 18.2-198 | - | 8.7-10.3 | - | - |
| Lean Duplex | 1.4362 | <0.03 | <1 | <2 | <0.035 | <0.015 | 22.0-24.0 | 0.10-0.60 | 3.50-5.50 | 0.10-0.60 | 0.05-0.20 |
Heat Treatment:
● Duplex stainless steel undergoes solution annealing, a heat treatment process that enhances its properties and ensures optimal performance in various applications.
Applications:
Duplex stainless steel bars find wide-ranging applications in various industries, including:
● Structural Design Components:
○ Ideal for structural elements requiring a blend of strength and corrosion resistance.
● Storage and Exchange Equipment:
○ Particularly suitable for high-pressure and saline applications, showcasing corrosion resistance.
● Heat Exchangers:
○ Widely used in the construction of heat exchangers, ensuring efficient heat transfer.
● Aerospace, Pulp and Paper Industry:
○ Duplex steel's unique properties make it suitable for demanding applications in aerospace and the pulp and paper industry.