Aircraft Alloy Steel AISI 4340 / E-4340


Technical Data Sheet

Alloy E 4340 is a widely used deep-hardening constructional steel. Due to E-4340's high alloy content it obtains a uniformed hardness by heat treatment. The high fatigue strength makes E4340 ideal for highly stress parts as it maintains it's strength and hardness at elevated temperatures.

Chemical Composition Limits
Weight% C Mn P & S Si Cr Ni Mo
E4340 Bar 0.38 - 0.43 0.65 - 0.85 0.025 0.15-0.30 0.70-0.90 1.65-2.00 0.20-0.30
E4340 Plate 0.38-0.43 0.60-0.80 0.025 0.15-0.35 0.70-0.90 1.65-2.00 0.20-0.30

Typical Mechanical Properties

 

Alloy Condition Tensile Strength ksi Yield Strength ksi Elongation 4D % Reduction of Area % Hardness HB
Alloy Steel E4340 Bar Annealed - - - - 235 max
Alloy Steel E4340 Bar Hardened and Tempered 260 217 10 30 -

Heat Treatment
To obtain the highest strength (260,000 psi minimum ultimate)

E 4340
Normalised 1650°F / 1 hr
Austenitise 1500°F / 1 hr
Quench Oil
Double Temper 475°F / 2 hr twice

Availability
Alloy E-4340 (4340) is available in Bar, Square, Round, Hexagon, Flat, Plates, Forging Stock and Welding Wire.  For all stock availability contact Sales.

Specifications
UNS G43406
AMS 6359 Sheet / strip / plate
AMS 6409 Bars / Forgings N&T
AMS 6414 Vac Melt Bars / Forgings
AMS 6415 Bars / Forgings
AMS 6484 Bars / Forgings N&T
AMS-S-5000
MIL-S-8844 Cl1
ASTM A322
ASTM A331
AISI E4340
BMS-7-28
BPS-299-947-055
BPS-299-949-055

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Disclaimer
Every effort is made to ensure that technical specifications are accurate. However, technical specifications included herein should be used as a guideline only. All specifications are subject to change without notice.