4340
AISI 4340 is a high-strength nickel-chromium-molybdenum alloy steel with excellent toughness and fatigue resistance. Supplied in quenched and tempered condition, it is suitable for highly stressed components.
Typical applications include aerospace parts, heavy-duty shafts, gears, and high-strength forgings.
Key Features
- Very high strength with excellent toughness
- Superior fatigue resistance
- Deep hardenability
- Good impact resistance
- Suitable for highly stressed components
Applications
- Aerospace components
- High-strength shafts
- Gears and crankshafts
- Heavy-duty forgings
- Defence and power transmission parts
Specifications
- UNS: G43400
- ASTM: A29, A322
- EN/DIN: 1.6582
- Structure: High Strength Alloy Steel (Ni-Cr-Mo)
- Condition Supplied: Quenched & Tempered
Data Tables
Chemical Composition:
| C | Mn | P | S | Si | Cr | Ni | Ti | Mo | N | Cu | Fe | Co | Nb (+Ta) | V | W | Al | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Min | 0.38 | 0.6 | 0.15 | 0.7 | 1.65 | 0.2 | |||||||||||
| Max | 0.43 | 0.8 | 0.035 | 0.04 | 0.35 | 0.9 | 2 | 0.3 | Bal |
Mechanical Properties:
| Material Grade | ASTM Standard | Desgnation(EN /UNS) | Yield Strength (MPa) | Yield Strength (KSI) | Tensile Strength (MPa) | Tensile Strength (KSI) | Elongation (%) | Reduction of Area (%) | Hardness(HRC/HBWMax) | Condition | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| AISI 4340 | ASTM A29 / A322 | EN 1.6582 | 850 | 123.2823 | 1000 | 145.038 | 14 | 35 | ≈300 HB | Q&T |
Physical Properties:
| Material Grade | Density (g/cm³) | Melting Range (°C) | Modulus of Elasticity (GPa) | Thermal Conductivity (W/m·K) | Thermal Expansion (×10⁻⁶ /°C) | Electrical Resistivity (µΩ·m) | Magnetic Behavior |
|---|---|---|---|---|---|---|---|
| AISI 4340 | 7.85 | 1427 | 205 | 44.5 | 12.3 | 0.25 | Magnetic |
Key Features
- Very high strength with excellent toughness
- Superior fatigue resistance
- Deep hardenability
- Good impact resistance
- Suitable for highly stressed components
Applications
- Aerospace components
- High-strength shafts
- Gears and crankshafts
- Heavy-duty forgings
- Defence and power transmission parts