300M steel is a vacuum melted low alloy steel with the inclusion of vanadium and a higher silicon composition. It has a very good fatigue strength and resilience. Where fracture toughness and impact strength are crucial, 300M is a great choice.
Typical Chemical Properties
| Minimum Properties | Tensile Strength , psi | 280,000 |
| Yield Strength, psi | 230,000 | |
| Elongation | 7% | |
| Rockwell Hardness | B 311 Max | |
| Chemistry | Carbon( C) | .38 -.42% |
| Chrome (Cr) | 0.70-0.95% | |
| Manganese (Mn) | 0.60-.90% | |
| Molybdenum (Mo) | 0.30 – .50% | |
| Nickel ( Ni) | 1.65-2.0% | |
| Phosphorus (P) | P & S – 0.10 % | |
| Sulphur (S) | P & S – 0.10 % | |
| Silicon (Si) | 1.45 – 1.80% | |
| Vanadium( V) | 0.05 – 0.10 % | |
| Copper ( Cu) | 0.35% |