Maraging Steel C250 Powder

Maraging Steel C250 Powder is an 18% nickel, cobalt strengthened steel (C250) alloy noted for its ultra-high strength and toughness without losing malleability. Maraging steels provide strengths 2 to 5 times higher than standard austenitic or martensitic grades via precipitation strengthening by intermetallic compounds.

Maraging steel C250 is supplied in powder form for additive manufacturing techniques like laser powder-bed fusion (LPBF) which allow printing complex geometries directly from digital CAD models. This enables rapid prototyping and production of lightweight, high-performance components for aerospace, automotive, medical, and tooling applications.

Overview of Maraging Steel C250 Powder

Maraging steel C250 powder has the following properties:

Table 1: Overview of Maraging Steel C250 Powder

Some key advantages of maraging steel C250 powder include:

• Ultrahigh tensile strength up to 2500 MPa after aging
• Higher elongation than typical stainless steels
• Good fracture toughness compared to high strength alloys
• Softer than precipitation hardening stainless grades in solutionized state for machining
• Lower distortion compared to martensitic steels during heat treatment
• Excellent dimensional stability during aging
• Easily welded in aged or solution treated condition

Maraging steel C250 does have some limitations as well:

• Requires aging treatment to develop full strength
• Relatively high alloy content increases cost
• Susceptible to embrittlement at high temperatures
• Lower hardness than martensitic stainless grades

Table 2: Composition of Maraging Steel C250 Powder

This composition creates a metastable martensitic matrix after solution annealing which allows for significant secondary hardening by homogeneous precipitation of intermetallic phases during the aging treatment.

Table 3: Key Properties of Maraging Steel C250 Powder

Applications of Maraging Steel C250 Powder

Maraging steel C250 powder has found usage across industries in the following applications due to its ultrahigh strength, fracture toughness, and thermal stability:

Aerospace Applications

• Turbine engine components like discs, shafts, fasteners
• Structural airframe components
• Rocket motor casings
• Aerospace fasteners, valves, fittings

Automotive Applications

• Motorsport powertrain parts like connecting rods, shafts
• High performance suspensions, chassis
• Dies, tooling

Industrial Applications

• Plastic injection molds
• Extrusion dies for pipes, tubes
• Blow molds
• Forging, stamping dies
• Grippers, end-effectors for robots

Table 4: Specifications, Grades, and Standards for Maraging Steel C250

Table 5: Suppliers and Pricing for Maraging Steel C250 Powder

Heat Treatment of Maraging Steel C250

Maraging steels are supplied in the annealed and descaled condition. A specific heat treatment procedure consisting of solution annealing followed by aging enables maraging steel C250 to attain its ultrahigh strength:

Solution Annealing

The first step is a homogenizing solution anneal typically done at 820°C ± 15°C for 1-3 hours followed by immediate cooling to room temperature. This renders the material soft but transforms the microstructure into a metastable martensitic matrix through slow cooling to prevent other equilibrium phases like ferrite or cementite from forming.

Aging

The solutionized maraging steel is then aged at a temperature between 400°C to 500°C for 3-6 hours depending on section thickness. This facilitates diffusion-controlled precipitation of intermetallic compounds like Ni₃Ti and Fe₂Mo which obstruct dislocation movement leading to significant strengthening.

Prolonged exposure at higher aging temperatures can compromise properties while insufficient temperature or time will prevent full hardening.

Table 6: Typical heat treatment process for maraging steel C250

The properties achieved after aging treatment are listed below:

Table 7: Mechanical properties after aging treatment

Induction Hardening: For certain components like shafts, gears and fasteners that require enhanced wear-resistance, additional surface hardening by induction heat treatment can be performed after aging to achieve hardness above 50 HRC up to a depth of 2 mm without affecting core properties.

Microstructure of Maraging Steel C250

The microstructure of maraging steel C250 consists of:

Martensitic Matrix: The matrix is predominantly martensite with fine-grained lath morphology produced by quenching after solution annealing. This metastable structure provides sufficient carbon and alloying elements in solid solution for precipitation during aging.

Intermetallic Precipitates: Spherical nano-scale precipitates of Ni₃Mo and Ni₃Ti phases dispersed uniformly through the matrix reaching peak volume fractions after full aging treatment. These coherent precipitates pin dislocation movement leading to drastic strengthening.

Carbides and Nitrides: Tiny cubic particles rich in titanium, molybdenum and iron carbides/nitrides may also emerge but comprise < 5% volume fraction.

The combination of tempered martensite matrix and fine dispersion of intermetallic precipitates enables the outstanding strength and toughness that maraging steels exhibit.

Printing Parameters for Maraging Steel C250 Powder