Alloy Steel AISI 4340 Forgings
4340, G43400
AISI 4340 alloy steel is a heat treatable and low alloy steel containing chromium, nickel and molybdenum. It has high toughness and strength in the heat treated condition.
Alloy steels are designated by AISI four-digit numbers. They comprise different kinds of steels having composition exceeding the limitations of B, C, Mn, Mo, Ni, Si, Cr, and Va set for carbon steels.
Alloy Steel AISI 4340 Forgings Properties
UNS G43400 Forgings Chemical Requirements
| Element | Fe | Ni | Cr | Mn | C | Mo | Si | S | P |
|---|---|---|---|---|---|---|---|---|---|
| Content (%) | 95.195 - 96.33 | 1.65 - 2.00 | 0.700 - 0.900 | 0.600 - 0.800 | 0.370 - 0.430 | 0.200 - 0.300 | 0.150 - 0.300 | 0.040 | 0.035 |
UNS G43400 Forgings Mechanical Requirements
| Properties | Metric | Imperial |
|---|---|---|
| Tensile strength | 745 MPa | 108000 psi |
| Yield strength | 470 MPa | 68200 psi |
| Bulk modulus (typical for steel) | 140 GPa | 20300 ksi |
| Shear modulus (typical for steel) | 80 GPa | 11600 ksi |
| Elastic modulus | 190-210 GPa | 27557-30458 ksi |
| Poisson's ratio | 0.27-0.30 | 0.27-0.30 |
| Elongation at break | 22% | 22% |
| Reduction of area | 50% | 50% |
| Hardness, Brinell | 217 | 217 |
| Hardness, Knoop (converted from Brinell hardness) | 240 | 240 |
| Hardness, Rockwell B (converted from Brinell hardness) | 95 | 95 |
| Hardness, Rockwell C (converted from Brinell hardness. Value below normal HRC range, for comparison purposes only) | 17 | 17 |
| Hardness, Vickers (converted from Brinell hardness) | 228 | 228 |
| Machinability (annealed and cold drawn. Based on 100 machinability for AISI 1212 steel.) | 50 | 50 |