Maraging Steel 250 Powder

Overview

Maraging steel 250 powder is a precipitation-hardenable steel powder that can be used for 3D printing or additive manufacturing applications. It has excellent strength and toughness combined with good weldability and ductility.

Some key properties and characteristics of maraging steel 250 powder include:

Composition: Iron-nickel alloy with 18-19% nickel, 7-9% cobalt, 3-5% molybdenum, 0.6-1.2% titanium and less than 0.1% carbon

Density: 8.1 g/cc

Melting point: 1480-1525°C

Ultimate tensile strength: >250 ksi (>1723 MPa) in aged condition

Elongation: 10-15% in aged condition

Hardness: 50 HRC in aged condition

Maraging steel gets its name from the combined effects of martensitic transformation and aging. The low carbon content allows formation of soft martensite upon rapid cooling. Subsequent aging at 480-510°C allows fine precipitation of intermetallic phases, imparting substantial strength and toughness.

The combination of properties makes maraging steel suitable for products requiring high strength along with toughness and weldability. The powder-bed based printing process allows complex parts to be manufactured.

Maraging Steel 250 Powder Composition

Maraging steels have low carbon concentrations, typically less than 0.1%. This prevents formation of carbides during aging which can make steel brittle.

The composition of grade 250 maraging steel powder is:

Table 1: Chemical composition of maraging steel 250 powder

Element	Weight %
Nickel	18-19
Cobalt	7-9
Molybdenum	3-5
Titanium	0.6-1.2
Carbon	<0.1
Iron	Balance

Small additions of titanium and aluminum are made to improve the hardening response. Carbon is kept low at under 0.1% to prevent unwanted carbide precipitation.

The low carbon along with balanced nickel and cobalt content gives an excellent combination of strength and toughness after aging treatment.

Production Method for Maraging Steel 250 Powder

Maraging steel is double melted in a vacuum induction melting furnace to ensure composition control. The melt is then rapidly solidified into powder using gas atomization process.

Table 2: Typical production method for maraging steel 250 powder

Step	Details
Melting	Vacuum induction melting
Rapid solidification	Inert gas atomization into fine powder
Sieving	Particle size classification
Sphericalization	For higher powder flowability

Gas atomization allows control over the powder size distribution and morphology. The powder particles are generally spherical in shape, with some satellites.

Typical size range is 15-45 microns, but smaller or larger sizes are also produced based on application requirements.

Properties of Maraging Steel 250 Powder

Maraging steel combines good workability in annealed state with very high strength in aged condition. It also has excellent toughness for a steel in this strength class.

Table 3: Overview of properties of maraging steel 250 powder in different conditions

Property	As-solidified	Aged
Yield Strength	~100 ksi	>250 ksi
Tensile Strength	120-140 ksi	>260 ksi
Elongation	20-25%	8-15%
Hardness	30 HRC	50 HRC
Toughness	Excellent	Good

The properties make it well suited for use both in as-printed and heat treated conditions. Parts can be machined easily after printing, then aged to gain substantial strength.

Heat Treatment of Maraging Steel 250 Powder

To achieve peak strength, maraging steel needs appropriate heat treatment. The standard procedure is:

• Solutionizing: Heat to 820-840°C, hold for 1-2 hours, cool rapidly
• Aging: Heat to 480-510°C, hold 3-6 hours, air cool

Solutionizing forms martensite by heating into the Austenite phase field followed by rapid cooling. This produces a soft phase ready for transformations during aging.

Aging leads to intermetallic precipitates forming in the martensite matrix. This imparts substantial increase in strength. Proper aging time and temperature is crucial.

Key Applications of Maraging Steel 250 Powder

The combination of properties makes maraging steel suitable for various demanding applications:

Table 4: Overview of key applications of maraging steel 250 powder

Industry	Applications	Benefits
Aerospace	Turbine blades, engine components	High strength, fracture toughness
Automotive	Chassis, drivetrain components	Strength, weldability
Tooling	Injection molds, forming dies	High strength, dimensional stability
General engineering	Shafts, casings, fixtures	Strength, toughness

• The ultra-high strengths achievable makes it suitable for critical static and dynamic load bearing parts.
• Excellent toughness reduces chance of sudden fracture failure.
• Good machinability in annealed state. Complex shapes can be machined after printing.
• Can be welded to assemble large components.
• Low thermal expansion gives excellent dimensional control for tooling applications.

Specifications and Standards

Maraging steel grade 250 conform to following specifications:

Table 5: Specifications and standards for maraging steel grade 250 powder

Standard	Designation	Country
ASTM	A743	USA
EN	1.2709	Europe

Equivalent standard grades from other countries:

• Japan: JIS G4805-SUH850
• China: GB 8162-99
• Russia: EP741N

Being a relatively new material, maraging steel specifications are still evolving. Customized grades are often produced for specific applications.

Suppliers and Pricing

Maraging steel 250 powder can be sourced from the following leading suppliers:

Table 6: Overview of some maraging steel 250 powder suppliers and approximate pricing

Company	Brand Names	Prices
Sandvik	Osprey 250	$100+/kg
EOS	MaragingSteel MS1	$90+/kg
Carpenter	Custom 450	$110+/kg
Praxair	Mara 250	$120+/kg

• Prices vary from $90-120+ per kg based on order volume and exact chemistry.
• Custom alloys tailored to application requirements also available.
• Small samples can be purchased online from 3D printing materials companies.

Comparison with Alternatives

Table 7: Comparison of maraging steel 250 with alternative materials

Property	Maraging Steel 250	17-4PH Stainless	Inconel 718	Titanium Ti64
Density	8.1 g/cc	7.8 g/cc	8.2 g/cc	4.4 g/cc
Tensile Strength	>260 ksi	190 ksi	190 ksi	130 ksi
Elongation	8-15%	12-20%	19-29%	10-25%
Corrosion Resistance	Moderate	Very Good	Excellent	Excellent
Thermal Properties	Average	Poor	Good	Average
Cost	High	Moderate	Very High	Moderate

Pros of maraging steel 250:

• Highest as-printed strength
• Excellent fracture toughness
• Good machinability and weldability
• Dimensional stability in heat treatment

Cons:

• Lower corrosion resistance than stainless or superalloys
• Higher cost than steels like 17-4PH
• Lower temperature capability than nickel alloys

Overall maraging steel 250 provides the best combination of ultra-high strength with medium cost compared to alternatives.

Conclusion

• Maraging steel 250 powder can achieve exceptional tensile strengths beyond 260 ksi after aging.
• It is widely used for critical components in aerospace, automotive, tooling and general engineering.
• The balanced nickel and cobalt composition gives optimized combination of strength and toughness.
• Excellent dimensional stability during solutionizing and aging makes it ideal for tooling applications.
• Powder-bed based 3D printing now allows very complex parts to be fabricated using this high strength steel powder.

FAQ

What is Maraging Steel 250 Powder?

Maraging Steel 250 Powder is a type of metal powder used in additive manufacturing processes like 3D printing. It is composed of maraging steel, which is known for its exceptional strength and toughness.

What are the key properties of Maraging Steel 250 Powder?

Maraging Steel 250 Powder is known for its high strength, excellent fracture toughness, and resistance to corrosion. It is also characterized by its ability to be heat treated to achieve even greater hardness.

What is the application of Maraging Steel 250 Powder?

This powder is used in various industries, including aerospace, automotive, and medical, to produce parts and components that require high strength and durability. Common applications include aerospace components, tooling, and medical implants.

How is Maraging Steel 250 Powder processed in 3D printing?

Maraging Steel 250 Powder is typically used in powder bed fusion processes like selective laser melting (SLM) or electron beam melting (EBM). In these processes, a high-energy laser or electron beam is used to selectively melt and fuse the powder particles layer by layer to create a 3D object.

What are the advantages of using Maraging Steel 250 Powder in 3D printing?

The advantages include its high strength-to-weight ratio, excellent mechanical properties, and the ability to produce complex geometries. It is also suitable for producing parts with intricate details.

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