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