4340 / 300M Aircraft Quality Manufacturer & Supplier
Ultra-high strength landing gear and structural steel. 300M is 4340 with silicon and vanadium added to reach 1860 MPa; both are vacuum melted for cleanliness and heat treated under AMS 2750 pyrometry control.
UNS: AMS 6414 / AMS 6417 · UNS G43400 / K44220 | Category: High Tensile Alloy Steel
Size Range
Outer Diameter: Bar 20-400 mm · plate to order
Chemical Composition (%)
| C | Ni | Cr | Si |
|---|---|---|---|
| 0.38-0.43 (4340) / 0.40-0.46 (300M) | 1.65-2.00 | 0.70-0.90 | 0.20 max / 1.45-1.80 |
Mechanical Properties
- Tensile Strength
- 1790 MPa min (4340) / 1860 MPa min (300M)
- Yield Strength
- 1520-1590 MPa min
- Elongation
- 8-10% min
- Hardness
- Per ordered property class
Applicable Standards
- AMS 6414
- AMS 6417
- AMS 2750
- ASTM E8
- EN 10204 3.1
Applications
- Landing gear components
- High load structural fittings
- Shafts, pins and actuator bodies
- Launcher and catapult hardware
- Overhaul and repair stock
Industries Served
- Airframe & Structures
- Engine & Propulsion
- Space & Launch
- Defence Aerospace
- MRO & Overhaul
- Ground Support Equipment
Equivalent Grades
- AMS 6414
- AMS 6414
- AMS 6417
- AMS 6417
- UNS G43400
- UNS G43400
- UNS K44220
- UNS K44220
- 300M
- 300M