High strength steel 300M plate, bar, tube, forging for aircraft landing gear, flap track and structural application

1 PRODUCT
Ultra-high strength steel 300M for aircraft landing gears, flap tracks and other structural applications.
Product forms available as plate, bar, tube, forging etc.

2 APPLICATION
Aircraft landing gears, flap tracks and other structural applications

3 OVERVIEW
300M steel is a modified 4340 steel with added silicon allowing for use of a higher tempering temperature. The steel has high hardenability and strength with good ductility and toughness in heavy sections. It is used primarily in the 270/300 ksi (1862/2068) tensile strength range for aircraft landing gears, flap tracks and other structural applications. Vacuum arc remelting (VAR) is used to provide optimum cleanliness and preferred ingot structure.

4 CHEMICAL COMPOSITION (wt%):
Table 1

5 PHYSICAL PROPERTIES
Density: 0.283 lb/in3 (7.84 g/cm3)
Thermal Conductivity: 260.0 Btu·in/hr·ft·°F (37.49 W/m·K)
Specific Heat: 0.107 Btu/lb·°F (448J/kg·K)
Mean Coefficient of Thermal Expansion 0-200°F (-17.8-93°C): 6.3x10-6 in/in·°F (11.34x10-6 mm/mm·°C)

6 MECHANICAL PROPERTIES
Typical transverse mechanical properties with575°F (302°C) temper

Fracture toughness per ASTM E399
At nominal strength levels, the ASTM E 399 plane-strain fracture toughness is typically 60-70 ksi √in. (66- 77 MPa √m).

Jominy end quench hardenability

7 WORKING INSTRUCTION
Forging
Forge at 1950-2250°F (1066-1232°C) using a minimum forging temperature of approximately 1700F (927°C).
Weldability
This steel can be welded by gas or arc fusion methods.
Machinability
For optimum machinability, 300M steel should be normalized and tempered. Approximately 1200°F(649°C) is suggested for the temper.
Hardness
Typically HBW 241-285.
Heat treatment
Normalize: 1700°F (927°C), 1 hour, air cool
Austenitize: 1600°F (871°C), 1 hour, oil quench
Temper: 500-600°F (260-316°F), four hours, air cool
Tempering curve
Austenitized 1600°F (871°C), Oil Quench, Tempered Twice 2+2 hours


8 STANDARD SPECIFICATION
The following industry specifications are offered for general familiarization and should not be considered a complete listing.
AMS 6257 (Replaces MIL-S-8844 Class 3)
AMS 6417 Steel, Bars, Forgings, and Tubing 1.6Si - 0.82Cr - 1.8Ni - 0.40Mo - 0.08V (0.38 - 0.43C) Consumable Electrode Vacuum Remelted
AMS 6419 Steel, Bars, Forgings, and Tubing 1.6Si - 0.82Cr - 1.8Ni - 0.40Mo - 0.08V (0.40 - 0.45C) Consumable Electrode Vacuum Remelted
BMS 7-26 (Boeing) BE1036 (Bendix) CE-0896 (Bendix)
C-05-1190 (Lockheed) DMS1935 (McDonnell-Douglas) GM1012 (Grumman)
MIL-S-83135
MTL 1201 (Messier-Dowty)

9 COMPETITIVE ADVANTAGE
(1) More than 50 years experience of research and develop in high temperature alloy, corrosion resistance alloy, precision alloy, refractory alloy, rare metal and precious metal material and products.
(2) 6 state key laboratories and calibration center.
(3) Patented technologies.
(4) Ultra-purity smelting process: VIM + IG-ESR + VAR
(5) Excellent high performance.

10 BUSINESS TERM