4340 VAR AMS 6414
4340 VAR is a premium melt aircraft quality steel with excellent ductility, toughness and high strength levels. It is considered a low alloy Chromium-Nickel-Molybdenum steel that has strong impact resistance as well as wear and abrasion resistance in the hardened condition.
Stock sizes: 1.000” to 10.000” diameter
Common Specifications:
- AMS 6414, AMS 6415
- Pratt & Whitney PWA-S-6414, PWA-S-6415
- Pratt & Whitney LCS F-17
- General Electric S-400 / S-SPEC-35
- McDonnell Douglas DMS 1555 Grade A
- Boeing BMS 7-28
- Bell BHT 299-947-055
- Sikorsky SS9702
Industry Trade Names:
- 4340 VAR
- SAE 4340
- AISI 4340
- 4340 CEVM
- Lescalloy 4340
Common Applications:
- Jet engines
- Gearboxes
- Landing gear
Macrostructure Limits:
| Class | Condition | Severity |
|---|---|---|
| 1 | Freckles | A |
| 2 | White Spots | A |
| 3 | Radial Segregation | B |
| 4 | Ring Pattern | B |
The average grain size shall be No. 5 or finer
Composition
| Element | Min. | Max. |
|---|---|---|
| Carbon | 0.38 | 0.43 |
| Manganese | 0.65 | 0.90 |
| Silicon | 0.15 | 0.35 |
| Phosphorus | — | 0.010 |
| Sulfur | — | 0.010 |
| Chromium | 0.70 | 0.90 |
| Nickel | 1.65 | 2.00 |
| Molybdenum | 0.20 | 0.30 |
| Copper | — | 0.35 |
The response to heat treatment tensile requirements are:
Minimum Longitudinal Tensile Properties:
| Property | Value |
|---|---|
| Tensile Strength | 260 ksi (1793 MPa) |
| Yield Strength at 0.2% Offset | 217 ksi (1496 MPa) |
| Elongation in 4D | 10% |
| Reduction of Area | 30% |
