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 strong impact resistance as well as wear and abrasion resistance in the hardened condition. 

Stock sizes: 1.000” to 10.000” diameters

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

Rockwell-Industries-4340-image

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%