to Alloy steels
to Properties of steels and cast irons
(submitted by the website administration)
| SAE 4340 | ||||
| Chemical composition: C=0.40%, Mn=0.7%, Mo=0.25%, Cr=0.8%, Ni-1.8% | ||||
| Property | Value in metric unit | Value in US unit | ||
| Density | 7.872 *10³ | kg/m³ | 491.4 | lb/ft³ |
|---|---|---|---|---|
| Modulus of elasticity | 205 | GPa | 29700 | ksi |
| Thermal expansion (20 ºC) | 12.6*10-6 | ºCˉ¹ | 7.00*10-6 | in/(in* ºF) |
| Specific heat capacity | 477 | J/(kg*K) | 0.114 | BTU/(lb*ºF) |
| Thermal conductivity | 44.6 | W/(m*K) | 309 | BTU*in/(hr*ft²*ºF) |
| Electric resistivity | 2.48*10-7 | Ohm*m | 2.48*10-5 | Ohm*cm |
| Tensile strength (annealed) | 745 | MPa | 108000 | psi |
| Yield strength (annealed) | 472 | MPa | 68500 | psi |
| Elongation (annealed) | 28 | % | 22 | % |
| Hardness (annealed) | 96 | RB | 96 | RB |
| Tensile strength (normalized) | 1279 | MPa | 195500 | psi |
| Yield strength (normalized) | 862 | MPa | 125000 | psi |
| Elongation (normalized) | 20 | % | 12 | % |
| Hardness (normalized) | 40 (112) | RC (RB) | 40 (112) | RC (RB) |