General Characteristics
Duplex grade with good resistance to localized corrosion and stress corrosion cracking in combination with high mechanical strength. Used in e.g. offshore topside applications since more than 20 years.
The grade is also available as 2304 with enhanced corrosion resistance and strength, but still within the same EN/ASTM standards as 2304.
Typical Applications
Desalination plants
Firewalls and blast walls on offshore platforms
Bridges
Components for structural design
Storage tanks
Pressure vessels
Heat exchangers
Water heaters
Rotors, impellers and shafts
Chemical Composition
The typical chemical composition for this grade is given in the table below, together with composition limits given for this grade according to different standards. The required standard will be fully met as specified on the order. The relatively low Ni and Mo content of 2304 and 2304 makes these grades more price stable compared to common standard stainless steel grades.
The typical chemical composition for this grade is given in the table below, together with composition limits given for the product according to different standards. The required standard will be fully met as specified on the order.
The chemical composition is given as % by mass.
C | Mn | Cr | Ni | Mo | N | Other | |
Typical | 0.02 | 23.0 | 4.8 | 0.3 | 0.10 | Cu:0.30 | |
ASME II A SA-240 | ≤0.030 | ≤2.50 | 21.5-24.5 | 3.00-5.50 | 0.05-0.60 | 0.05-0.20 | Cu:0.05-0.60 |
ASTM A240 | ≤0.030 | ≤2.50 | 21.5-24.5 | 3.0-5.5 | 0.05-0.60 | 0.05-0.20 | Cu:0.05-0.60 |
EN 10028-7 | ≤0.030 | ≤2.00 | 22.0-24.0 | 3.5-5.5 | 0.10-0.60 | 0.05-0.20 | Cu:0.10-0.60 |
EN 10088-2 | ≤0.030 | ≤2.00 | 22.0-24.5 | 3.5-5.5 | 0.10-0.60 | 0.05-0.20 | Cu:0.10-0.60 |
EN 10088-3 | ≤0.030 | ≤2.00 | 22.0-24.0 | 3.5-5.5 | 0.10-0.60 | 0.05-0.20 | Cu:0.10-0.60 |
EN 10088-4 | ≤0.030 | ≤2.00 | 22.0-24.0 | 3.5-5.5 | 0.10-0.60 | 0.05-0.20 | Cu:0.10-0.60 |
IS 6911 | ≤0.030 | ≤2.50 | 21.5-24.5 | 3.0-5.5 | 0.05-0.60 | 0.05-0.20 | Cu:0.05-0.60 |
Mechanical Properties
The duplex stainless steels have much higher mechanical strength compared to standard stainless steels. If the high strength of the duplex grades can be utilised, down gauging can be done in many applications leading to cost efficient solutions. The allowable design values may vary between product forms. The appropriate values are given in the relevant specifications. The product types P= hot rolled plate, H=hot rolled strip and C=cold rolled coil and strip.
| Standard | Rp0.2 | Rp1.0 | Rm | Elongation | Rockwell | HB |
MPa | MPa | MPa | % | |||
Product type: Cold rolled coil and sheet | ||||||
Typical (thickness 1 mm) | 620 | 660 | 790 | 42 | ||
ASME II A SA-240 | ≥ 400 | ≥ 600 | ≤ 290 | |||
ASTM A240 | ≥ 400 | ≥ 600 | ≤ 32HRC | ≤ 290 | ||
EN 10028-7 | ≥ 420 | 600-850 | ≥ 20 | |||
EN 10088-2 | ≥ 450 | 650-850 | ≥ 20 | |||
EN 10088-4 | ≥ 450 | 650-850 | ≥ 20 | |||
IS 6911 | ≥ 400 | ≥ 600 | ≤ 32HRC | ≤ 290 | ||
Product type: Hot rolled coil and sheet | ||||||
Typical (thickness 4 mm) | 600 | 670 | 765 | 30 | 235 | |
ASME II A SA-240 | ≥ 400 | ≥ 600 | ≤ 290 | |||
ASTM A240 | ≥ 400 | ≥ 600 | ≤ 290 | |||
EN 10028-7 | ≥ 420 | 600-850 | ≥ 20 | |||
EN 10088-2 | ≥ 420 | 650-850 | ≥ 20 | |||
EN 10088-4 | ≥ 420 | 650-850 | ≥ 20 | |||
IS 6911 | ≥ 400 | ≥ 600 | ≤ 32HRC | ≤ 290 | ||
Product type: Hot rolled quarto plate | ||||||
Typical (thickness 15 mm) | 450 | 670 | 40 | 210 | ||
ASME II A SA-240 | ≥ 400 | ≥ 600 | ≤ 32HRC | ≤ 290 | ||
ASTM A240 | ≥ 400 | ≥ 600 | ≤ 32HRC | ≤ 290 | ||
EN 10028-7 | ≥ 400 | 630-800 | ≥ 25 | |||
EN 10088-2 | ≥ 400 | 630-800 | ≥ 25 | |||
EN 10088-4 | ≥ 400 | 630-800 | ≥ 25 | |||
IS 6911 | ≥ 400 | ≥ 600 | ≤ 32HRC | ≤ 290 | ||
Physical Properties
The physical properties at room temperature are shown in the table below. Data according to EN10088 or EN10095.
| Density | Modulus of elasticity | Thermal exp. at 100 °C | Thermal conductivity | Thermal capacity | Electrical resistance | Magnetizable |
kg/dm3 | GPa | 10-6/°C | W/m°C | J/kg°C | µΩm | |
7.8 | 200 | 13 | 15 | 500 | 0.8 | Yes |
