ALLOY & CARBON STEEL 4340
Chemical Composition
Element | Min | Max |
|---|---|---|
| Carbon, C | 0.35 | 0.45 |
| Manganese, Mn | 0.45 | 0.70 |
| Silicon, Si | 0.10 | 0.35 |
| Nickel, Ni | 1.3 | 1.8 |
| Molybdenum, Mo | 0.20 | 0.35 |
| Chromium,Cr | 0.90 | 1.40 |
| Sulfur, S | -.-- | 0.5 |
| Phosphorous, P | -.-- | 0.5 |
Mechanical Properties
Properties | Metric | Imperial |
|---|---|---|
| Tensile strength | 745 MPa | 108000 psi |
| Yield strength | 470 MPa | 68200 psi |
| Bulk modulus (typical for steel) | 140 GPa | 20300 ksi |
| Shear modulus (typical for steel) | 80 GPa | 11600 ksi |
| Elastic modulus | 190-210 GPa | 27557-30458 ksi |
| Poisson's ratio | 0.27-0.30 | 0.27-0.30 |
| Elongation at break | 0.22 | 0.22 |
| Reduction of area | 0.5 | 0.5 |
| Hardness, Brinell | 217 | 217 |
| Hardness, Knoop (converted from Brinell hardness) | 240 | 240 |
| Hardness, Rockwell B (converted from Brinell hardness) | 95 | 95 |
| Hardness, Rockwell C (converted from Brinell hardness. Value below normal HRC range, for comparison purposes only) | 17 | 17 |
| Hardness, Vickers (converted from Brinell hardness) | 228 | 228 |
| Machinability (annealed and cold drawn. Based on 100 machinability for AISI 1212 steel.) | 50 | 50 |
Thermal Properties
Properties | Metric | Imperial |
|---|---|---|
| Thermal expansion co-efficient (20°C/68°F, specimen oil hardened, 600°C (1110°F) temper | 12.3 µm/m°C | 6.83 µin/in°F |
| Thermal conductivity (typical steel) | 44.5 W/mK | 309 BTU in/hr.ft².°F |
Features
Heat Treatment
Tempering
Hardening
Normalizing
Soft Annealing
Forging
