300M VAC-ARC Steel is a modified 4340 alloy steel with high hardenability and very high strength. This is achieved with the inclusion of vanadium and a higher silicon composition. 300M is a great choice where fracture toughness and impact strength are crucial. It is used mostly in the 270/300 KSI tensile strength range for aircraft gears, flap tracks and other structural applications.
Vacuum Arc Remelting (VAR) improved the cleanliness and preferred ingot structure.
This material is also called 4340 MOD VAC MELT.
Specifications:
- UNS K44220
- AMS 6257
- AMS 6417
- AMS 6419
- BMS-7-26
- DMS91935
- GM-1012
- ASTM A646
- ASTM A579
- MIL-S-8844
Applications:
Aircraft gears, flap tracks, high strength bolts, airframe parts, driveshafts, missile components,