Topics Covered
Background
300M Alloy
300M Alloy Industry Standard
Applications of 300M Alloy
Heat Treatment of 300M Alloy
Chemical Composition of 300M Alloy
Mechanical Properties of 300M Alloy
Physical Properties of 300M Alloy
Available Product Forms of 300M Alloy
Background
The Super Alloys management team are amongst the most experienced professionals in the market. Supported by professional metallurgists and technicians, Super Alloys not only provide access to the largest range of high-tec metals in Europe, but also access to the broadest range of expertise.
The unique combination of access to stock, expertise and rapid delivery reduces lead times and can eliminate costly production delays.
The Super Alloys range of materials includes:
Titanium Alloys
Nickel Alloys
Steels
300M Alloy
300M is a low alloy, vacuum melted, steel of very high strength. Essentially it is a modified AISI 4340 steel with silicon, vanadium and slightly more carbon and molybdenum. 300M has a very good combination of strength at 1930-2100 MPa (280-305 ksi), toughness, fatigue strength and good ductility. It is a through hardening alloy.
300M Alloy Industry Standard
300M alloy complies with the AMS 6419 industry standard and is also known as UNS K44220.
Applications of the 300M Alloy
The 300M alloy is use for a wide range of applications including:
aircraft landing gear
high strength bolts
airframe parts
driveshafts
Heat Treatment of 300M Alloy
300M must be normalized at 927°C (1700℉) before hardening. After the normalizing treatment, the alloy is hardened by heating to 871°C (1600℉) and oil quenching. After hardening the material is double tempered for 2 hours at 302°C (575℉) and 2 hours at 302°C (575℉) air cool.
Chemical Composition of 300M Alloy
The Super Alloys ultra-high strength 300M alloy has the following chemical composition that gives it its unique properties.
Table 1. Chemical composition of 300M alloy
| Chemical Elements | Min | Max |
| Nickel | 1.65 | 2 |
| Molybdenum | 0.3 | 0.65 |
| Carbon | 0.38 | 0.46 |
| Phosphorus | - | 0.01 |
| Sulfur | - | 0.01 |
| Silicon | 1.45 | 1.8 |
| Titanium | 0.3 | 0.5 |
| Manganese | 0.6 | 0.9 |
| Iron | 94 | - |
| Chromium | 0.7 | 0.95 |
| Vanadium | - | 0.05 |
Mechanical Properties of 300M Alloy
The mechanical properties of 300M alloy following different heat treatments are outlined in the following tables.
Table 2. Mechanical properties for normalized, hardened and double tempered
| Metric | English | |
| Tensile Strength, Ultimate | 1931 MPa | 280 ksi |
| Tensile Strength, Yield | 1586 MPa | 230 ksi |
| Percent Elongation | 7.00% |
Physical Properties of 300M Alloy
The physical properties of 300M alloy are outlined in the following table.
Table 3. Physical properties of 300M alloy
| Metric | English | |
| Thermal Expansion 20°C (68℉) | 11.34µm/m-°C | 6.300µin/in-℉ |
| Specific Heat Capacity | 0.448 J/kg-°K | 0.107 BTU/lb-℉ |
| Thermal Conductivity | 37.49 W/m-°C | 260.2 BTU-in/hr-ft2-℉ |
Available Product Forms of 300M Alloy
300M alloy is available in the forms of plate, bar, sheet, tube, billet, and forging