Forged and Hot Rolled 4340 Alloy Steel Round Bars
4340 alloy steel round bars are supplied in forged and hot rolled condition. AISI 4340 forged steel bars and SAE 4340 hot rolled alloy steel bars are in equivalent in UNS G43400.
4340 alloy steel round bar is a widely used deep-hardening constructional steel. Due to 4340's high alloy content, it obtains a uniformed hardness by heat treatment. The high fatigue strength makes 4340 alloy bar ideal for highly stress parts as it maintains it's strength and hardness at elevated temperatures.
4340 Alloy Steel Round Bars Typical Mechanical Properties
Alloy |
Condition |
Tensile Strength ksi |
Yield Strength ksi |
Elongation 4D % |
Reduction of Area % |
Hardness HB |
Alloy Steel 4340 Bar |
Annealed |
- |
- |
- |
- |
235 max |
Alloy Steel 4340 Bar |
Hardened and Tempered |
260 |
217 |
10 |
30 |
- |
4340 Alloy Steel Round Bars Heat Treatment
To obtain the highest strength (260,000 psi minimum ultimate)
Normalised |
1650°F / 1 hr |
Austenitise |
1500°F / 1 hr |
Quench |
Oil |
Double Temper |
475°F / 2 hr twice |
AISI/ SAE alloy steel bar 4340 is available in Bar, Square, Round, Hexagon, Flat, and Plates. If you are looking for 4340 forged steel round bar or 4340 hot rolled alloy steel bar, please contact our Sales.