4340 Steel
Standards
| Mat. No. | DIN | EN | AISI/SAE |
| – | – | – | 4340 |
Typical Chemical Composition (in weight %)
| C | Si | Mn | Cr | Mo | Ni | V | W | Others |
| 0.46 | 0.27 | 0.65 | 0.95 | 0.25 | 1.55 | 0.14 | – | – |
Description
4340 is a heat treatable, low alloy steel containing nickel, chromium and molybdenum. It is known for its toughness and capability of developing high strength in the heat treated condition while retaining good fatigue strength.
Applications
Permanently stressed machine, engine and vehicle parts when high strength and toughness are required. Typical applications are for structural use, such as aircraft landing gear, power transmission gears and shafts and other structural parts.
Physical properties (average values) at ambient temperature
Modulus of elasticity [103 x N/mm2]: 210 Density [g/cm3]: 7.85
Soft Annealing
A full anneal may be done at 840℃ followed by controlled (furnace) cooling at a rate not faster than 10℃ per hour down to 300℃. From 300℃ it may be air cooled.
Normalizing
Temperature: 890℃
Hardening
Harden from a temperature of 830℃ followed by oil quenching.
Tempering
The temperature for tempering depends upon the strength level desired. Before tempering the alloy should be in the heat treated or normalized & heat treated condition. For strength levels in the 260 – 280 ksi range temper at 230℃.
Disclaimer: the information and data presented herein are typical values for reference and are not intended as warranties to readers.
