General Properties
Alloy 2304 is a 23% chromium, 4% nickel, molybdenum-free duplex stainless steel. The Alloy 2304 has corrosion resistance properties similar to 316L. Furthermore, its mechanical properties, i.e., yield strength, are twice those of 304/316 austenitic grades. This allows the designer to save weight, particularly for properly designed pressure vessel applications.
The alloy is particularly suitable for applications covering the -50°C/+300°C (-58°F/572°F) temperature range. Lower temperatures may also be considered but need some restrictions, particularly for welded structures.
With its duplex microstructure and low nickel and high chromium contents, the alloy has improved stress corrosion resistance properties compared to 304 and 316 austenitic grades.
Chemical Analysis
Typical Values (Weight %)
| Carbon | Chromium | Nickel | Molybdenum | Nitrogen | Others |
|---|---|---|---|---|---|
| 0.020 | 23 | 4 | 0.2 | 0.1 | S=0.001 |
| PREN = [Cr%] = 3.3 [Mo%] = 16 [N%] ≥ 24 |
Mechanical Properties
Tensile Properties (Minimum Values)
| °C | Rp 0.2 MPa | Rp 1.0 MPa | Rp 1.0 MPa | °F | YS 0.2% Offset KSI | YS 0.1% Offset KSI | UTS KSI | Elongation % |
|---|---|---|---|---|---|---|---|---|
| 20 | 400 | 440 | 600 | 68 | 58 | 64 | 87 | 25 |
| 100 | 330 | 365 | 570 | 212 | 48 | 53 | 83 | 25 |
| 200 | 280 | 310 | 530 | 392 | 41 | 45 | 77 | 20 |
| 300 | 230 | 260 | 490 | 572 | 33 | 38 | 71 | 20 |
Values obtained for hot rolled plates (th ≤ 2"). Alloy 2304 must not be used for a long time at temperatures higher than 300°C (572°F), where precipitation hardening phenomenon occurs.
Toughness Values (KCV Minimum Values)
| Temp. | -50°C | +20°C | -60°F | +70°F |
|---|---|---|---|---|
| Single | 75 J/cm_ | 90 J/cm_ | 54 ft. lbs | 65 ft. lbs |
| Average (5) | 90 J/cm_ | 150 J/cm | 65 ft. lbs | 87 ft. lbs |
Hardness (Typical Values)
| Average (5) | HV10 180-230 | HB : 180-230 | HRC _ 20 |
Physical Properties
Density : 7,800 kg/m3 - 0.28 lb/in3
| Interval Temper °C | Thermal expansion ax10M-bK-1 | °C | Resistivity (μ_ cm) | Thermal conductivity (W.m-1.K-1) | Specific heat (J.kg-1.K-1 | Young modulus E (GPa) | Shear modulus G (GPa) |
|---|---|---|---|---|---|---|---|
| 20-100 | 13 | 20 | 80 | 17 | 450 | 200 | 75 |
| 20-100 | 13 | 100 | 92 | 18 | 500 | 190 | 73 |
| 20-200 | 13.5 | 200 | 100 | 19 | 530 | 180 | 70 |
| 20-300 | 14 | 300 | 105 | 20 | 560 | 170 | 67 |
