Alloy Steel 8740
Material Data Sheet
8740 is a Nickel Chrome Moly produced for case hardening. It can often be found in aerospace applications, when wear resistance, toughness, and strength are needed.
Chemical Composition
| Chemistry | Content(%) |
|---|---|
| Iron, Fe | 96.595 – 97.72 |
| Manganese, Mn | 0.75 – 1.0 |
| Nickel, Ni | 0.4 – 0.7 |
| Chromium, Cr | 0.4 – 0.6 |
| Carbon, C | 0.38 – 0.43 |
| Molybdenum, Mo | 0.20 – 0.30 |
| Silicon, Si | 0.15 – 0.30 |
| Phosphorous, P | ≤ 0.035 |
| Sulfur, S | ≤ 0.04 |
Physical Properties
| Properties | Metric | Imperial |
|---|---|---|
| Density | 7.85 g/cc | 0.284 lb/in³ |
Mechanical Properties
| Properties | Metric | Imperial |
|---|---|---|
| Hardness, Brinell | 269 | 269 |
| Hardness, Knoop | 294 | 294 |
| Hardness, Rockwell B | 99 | 99 |
| Hardness,Rockwell C | 27 | 27 |
| Hardness, Vickers | 284 | 287 |
| Tensile Strength, Ultimate | 938 MPa | 136000 psi |
| Tensile Strength, Yield | 620 MPa | 89900 psi |
| Elongation at Break | 16% | 16% |
| Modulus of Elasticity | 205 GPa | 29700 ksi |
| Bulk Modulus | 160 GPa | 23200 ksi |
| Poissons Ratio | 0.29 | 0.29 |
| Machinability | 65% | 65% |
| Shear Modulus | 80.0 GPa | 11600 ksi |
Applications
Alloy Steel 8740 is used in the following application areas:
- Aerospace Engine Parts
- Aerospace Subassemblies
- Aerospace Fasteners
