Alloy 250 is an age-hardenable (maraging) iron-nickel steel, combining ultra-high strength, toughness and resistance to crack propagation.
Maraging Alloy 250 Industry Standard
S162 British Standard and is also known as UNS K44220.
Applications of Maraging Alloy 250
The maraging alloy 250 has a wide range of application including:
- Rocket motor casings
- Light aircraft landing gear
- Power shafts
- Low temperature tooling
Heat Treatment of Maraging Alloy 250
Hardening is accomplished by a simple aging cycle of 3 to 6 hours at 485°C (900°F), followed by air cooling. Alloy 250 provides through hardening without quenching, freedom from decarburization, minimal distortion during aging, good formability, machinability, and weldability and a low coefficient of thermal expansion.
Chemical Composition of Maraging Alloy 250
The Super Alloys ultra-high strength maraging alloy 250 has the following chemical composition that gives it its unique properties.
Table 1. Chemical composition of maraging alloy 250
|
Chemical Elements
|
Min
|
Max
|
|
Nickel
|
17.0
|
19.0
|
|
Molybdenum
|
4.6
|
5.1
|
|
Cobalt
|
7.0
|
8.5
|
|
Carbon
|
-
|
0.03
|
|
Aluminum
|
0.05
|
0.15
|
|
Phosphorus
|
-
|
0.01
|
|
Sulfur
|
-
|
0.01
|
|
Silicon
|
-
|
0.10
|
|
Titanium
|
0.3
|
0.5
|
|
Manganese
|
-
|
0.01
|
|
Iron
|
68.0
|
-
|
Mechanical Properties of Maraging Alloy 250
The mechanical properties of maraging alloy 250 following different heat treatments are outlined in the following tables.
Table 2. Mechanical properties for solution annealed maraging alloy 250
|
816°C (1500°F), 1hr, AC
|
Metric
|
English
|
|
Tensile Strength, Ultimate
|
1000 MPa
|
145 ksi
|
|
Tensile Strength, Yield
|
793 MPa
|
115 ksi
|
|
Percent Elongation
|
20%
|
|
Table 3. Mechanical properties for solution annealed and aged maraging alloy 250
|
485°C (900°F), 3-6hrs, Ac
|
Metric
|
English
|
|
Tensile Strength, Ultimate
|
1800 MPa
|
260 ksi
|
|
Tensile Strength, Yield
|
1700 MPa
|
246 ksi
|
|
Percent Elongation
|
8%
|
|
Physical Properties of Maraging Alloy 250
The physical properties of maraging alloy 250 are outlined in the following table.
Table 4. Physical properties of maraging alloy 250
|
|
Metric
|
Imperial
|
|
Thermal Expansion 21°C (70°F)
|
9.72 µm/m-°C
|
5.4 µin/in-°F
|
|
Specific Heat Capacity
|
293 J/kg-°K
|
0.07 BTU/lb-°F
|
|
Thermal Conductivity
|
19.6 W/m-°C
|
136 BTU-in/hr-ft2-°F
|
Available Product Forms of Alloy 250
Maraging alloy 250 is available in the forms of plate, bar, sheet, tube, billet, and forging
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This information has been sourced, reviewed and adapted from materials provided by NeoNickel.
For more information on this source, please visit NeoNickel.