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. 

Common stock sizes: 1.500” to 15.000” 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%