AISI 4340
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. 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.
| Element | Content(%) |
|---|---|
| Iron, Fe | 95.195 - 96.33 |
| Nickel, Ni | 1.65 - 2.00 |
| Chromium, Cr | 0.700 - 0.900 |
| Manganese, Mn | 0.600 - 0.800 |
| Carbon, C | 0.370 - 0.430 |
| Molybdenum, Mo | 0.200 - 0.300 |
| Silicon, Si | 0.150 - 0.300 |
| Sulfur, S | 0.0400 |
| Phosphorous, P | 0.0350 |
| 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 |
Sheets / Plates
| Production Route | Hot Rolled, Cold Rolled |
| Material Standard | AISI, ASTM, ASME, DIN, BS, EN, ISO, JIS, GOST, SAE, IS & Custom Chemistry |
| Size | Width from 100mm to 3000mm ; Length from 500mm to 12000mm |
| Thickness | 0.1mm to 400mm |
| Delivery Condition | As Rolled, Annealed, Quenched and Tempered, Normalized |
| Surface Finish | Plain, Brushed, Cladded |
AISI 4340 Equivalent Grade / Specifications
- AMS 6359
- AMS 6454
- ASTM A331 (4340)
- ASTM A711
- SAE J1397 (4340)
- AMS 6409
- ASTM A29 (4340)
- ASTM A506 (4340)
- ASTM A752 (4340)
- SAE J404 (4340)
- AMS 6414
- ASTM A320 (L43)
- ASTM A519 (4340)
- ASTM A829
- SAE J412 (4340)
- AMS 6415
- ASTM A322 (4340)
- ASTM A646 (4340-7)
- MIL S-5000