AISI 4340 Alloy Steel — High-Strength Nickel-Chromium-Molybdenum Properties
ASTM A322 · Published: 2026-06-30 · Updated: July 2026
AISI 4340 is an ultra-high-strength nickel-chromium-molybdenum alloy steel used in aircraft landing gear, crankshafts, and high-stress applications.
AISI 4340 is an ultra-high-strength nickel-chromium-molybdenum alloy steel used in aircraft landing gear, crankshafts, and high-stress applications.
Quick Facts
| Category | |
| Standard | ASTM A322 |
| Density | 7850 |
| Yield Strength | 860 MPa |
| Tensile Strength | 1030 MPa |
Global Equivalents & Cross-Reference
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Calculate the weight based on this material's density: 7850
References & International Standards
- ASTM International. Standard Specifications for Steel & Metal Alloys. astm.org
- International Organization for Standardization (ISO). Metallic Materials — Cross-Reference Database. iso.org
- American Iron and Steel Institute (AISI). Steel Grade Designations & Equivalents. steel.org
- European Committee for Standardization (CEN). EN Steel Standards & Numbering System. cencenelec.eu
Structural & Alloy Steel — Engineering Reference
Structural steels are the backbone of construction and heavy industry. Grades in this category are specified primarily by their yield strength, tensile strength, and weldability — the three properties that determine whether a building stands or a bridge holds.
ASTM A36/A572/A516, EN 10025, JIS G3101/G3106, GB/T 700/1591
Building frames, bridges, pressure vessels, shipbuilding, offshore platforms, pipelines
When selecting a structural grade, match the required yield strength to the design load, but also verify Charpy impact values if the structure will operate below freezing — many structural steels undergo a ductile-to-brittle transition at low temperatures.