Alloy X-750 Powder

Alloy X-750 is a nickel-chromium-iron-molybdenum alloy that offers excellent corrosion resistance and high-temperature strength. It is widely used in applications that require resistance to aqueous corrosion, oxidation and other chemical environments.

Alloy X-750 powder metallurgy allows parts to be manufactured through methods like metal injection molding (MIM), hot isostatic pressing (HIP), additive manufacturing, and spray deposition. These techniques enable the production of small, complex components with fine microstructures.

Overview of Alloy X-750 Powder

Alloy X-750 powder has the following key characteristics:

Composition: Nickel-chromium-iron alloy with molybdenum, titanium, aluminum, and niobium additions

Particle shape: Spherical, irregular or mixed

Size range: 1-100 microns

Common size grades: -100 mesh, -325 mesh, 10-45 microns

Production methods: Gas atomization, water atomization

Key properties: Excellent corrosion resistance, high-temperature strength, oxidation resistance, phase stability

Main applications: MIM, HIP, AM, thermal spray coatings

Advantages: Allows small, complex component fabrication, microstructural control, near-net-shape production

Limitations: Higher cost than wrought products, powder handling challenges, parameter optimization needed

Chemical Composition

Alloy X-750 powder has a typical composition as shown below:

Alloy X-750 Powder Composition

Element	Weight %
Nickel (Ni)	72.0 min
Chromium (Cr)	14.0-17.0
Iron (Fe)	5.0-9.0
Molybdenum (Mo)	8.0-10.0
Titanium (Ti)	0.7-1.2
Aluminum (Al)	0.2-0.8
Niobium (Nb)	0.4-1.0

The nickel provides corrosion resistance while chromium improves high temperature strength and molybdenum enhances creep resistance. Minor additions of titanium, aluminum and niobium optimize mechanical properties. The composition is balanced to maximize performance in harsh environments up to 1300°F.

Powder Characteristics

Alloy X-750 powder is characterized by properties like particle shape, size distribution, flow rate, apparent density, and microstructure.

Particle Shape

• Spherical, satellite, irregular or mixed
• Sphericity impacts packing density, flowability
• Satellites can cause segregation issues

Size Distribution

• Represented by D10, D50 and D90 particle sizes
• Narrow distribution ensures uniform properties
• Common size grades: -100 mesh, -325 mesh, 10-45 microns

Flow Rate

• Angle of repose under 30° ensures good flow
• Affected by factors like particle shape, size range
• Important for powder feeding during AM or MIM

Apparent Density

• Density packed powder bed, usually 40-60% of alloy density
• Influences final part density and properties

Internal Microstructure

• Gas atomized powder has fine grains and defects
• Water atomized powder has large satellites and pores
• Defects can act as failure points during service

Powder Production Methods

The two main production routes for Alloy X-750 powder are:

Gas Atomization

• Molten alloy stream impinges on gas jets
• Produces spherical particles with lower oxygen pickup
• Allows better control of size distribution

Water Atomization

• Molten stream impinges on water jets
• Yields smaller particles than gas atomization
• Causes high oxygen content and satellites

Gas atomized powder has generally powder characteristics but water atomized powder has cost benefits for some applications. The powder production method controls final particle shape, defects level and flow behavior.

Mechanical Properties

Alloy X-750 powder enables engineering components with the following mechanical properties through correct processing:

Alloy X-750 Powder Mechanical Properties

Property	As-HIP Condition	Precipitation Hardened
Density	8.22 g/cc	8.22 g/cc
Tensile Strength	105-120 ksi	160-185 ksi
Yield Strength	40-60 ksi	140-170 ksi
Elongation	35-40%	15-25%
Hardness	Rockwell B 80-85	Rockwell C 35-42

HIP parts show lower strength in the as-HIP condition. Further heat treatment induces precipitation hardening raising strength levels while lowering ductility. Parts can be fabricated to meet diverse mechanical property requirements through process optimization.

High Temperature Performance

Precipitation hardened Alloy X-750 powder components exhibit the following properties at high temperatures:

Alloy X-750 Powder High Temperature Performance

Temperature	700°F	1000°F	1200°F	1300°F
Tensile Strength (ksi)	160	140	120	110
Creep Rupture Life (hrs)	1000	500	200	100
Oxidation resistance	Excellent	Very Good	Good	Fair

Alloy X-750 resists softening, creep and oxidation up to 1300°F making it well suited for structural applications under long-term mechanical loading and corrosive environments. It outperforms stainless steels and lower alloyed products.

Fabrication Techniques Using Alloy X-750 Powder

The key methods for processing Alloy X-750 powder include:

Metal Injection Molding (MIM)

• Mixing with binders, mold injection, solvent debinding, sintering
• Allows complex, precision net-shape components
• Tight dimensional control, excellent surface finish

Hot Isostatic Pressing (HIP)

• Consolidating encapsulated powder using high pressure
• Produces near net-shape parts, low machining
• Can eliminate internal porosity, refine grains

Additive Manufacturing (AM)

• Building parts layer-by layer using laser/electron beams
• Ideal for prototypes, small production runs
• Design freedom for complex shapes

Thermal Spray Coatings

• Depositing molten powder on substrates
• Wear/corrosion resistant coatings possible
• Limited coating thickness/build-up

Each technique utilizes the beneficial powder characteristics for high-performance component manufacturing.

Applications of Alloy X-750 Powder

Due to its excellent elevated temperature performance and corrosion resistance, Alloy X-750 powder is used to manufacture components for:

Oil and Gas Extraction

• Downhole tools, valves, wellheads
• Pumps, pressure vessels, piping elements

Aerospace and Defense

• Engine components like combustion cans, spacers
• Airframe parts subjected to fatigue and heat

Automotive and Motorsports

• Turbocharger rotors and housings
• Exhaust system components and manifolds

Chemical Processing Industry

• Heat exchangers, reaction vessels
• Pumps and valves for corrosive fluids

Biomedical Industry

• Surgical instruments like scalpels, clamps
• Implants and prosthetic devices

Energy Generation

• Heat exchangers for concentrating solar power
• Nuclear reactor internals and tooling

The combination of fabricability, mechanical performance and corrosion resistance allows Alloy X-750 powder to serve critical applications across industries where reliability and safety are vital.

Suppliers of Alloy X-750 Powder

Alloy X-750 powder suitable for HIP, AM and MIM can be sourced from manufacturers like:

Alloy X-750 Powder Suppliers

Supplier	Production Method	Particle Sizes
Sandvik Osprey	Gas atomized	15-45 microns
TLS Technik	Gas atomized	10-50 microns
Carpenter Powder Products	Gas atomized	-100 mesh to -325 mesh
Hoganas	Water atomized	Under 45 microns
Pometon Powder	Gas atomized	10-63 microns

These companies can provide various particle size distributions and powder characteristics to meet application requirements. Some also offer toll powder processing services.

Cost Analysis

Alloy X-750 powder is more expensive than standard stainless steel powders. Some typical powder prices are:

Alloy X-750 Powder Pricing

Supplier	Powder Type	Cost
Sandvik	Osprey X-750 -100 mesh	$165/kg
TLS Technik	Atomized X-750 20-63 μm	$100/kg
Hoganas	Water atomized	$75/kg
Pometon	Gas atomized 10-45 μm	$140/kg

Cost depends strongly on particle size range, production method (gas vs water atomization), order volume, and purity level. Prices above are approximate for reference. Operations like HIP and MIM using Alloy X-750 powder enable significant cost reduction over machining from bulk alloys.

FAQs

Q: What is the difference between gas and water atomized Alloy X-750 powder?

A: Gas atomization produces more spherical particles with lower oxygen pickup and better size distribution control compared to water atomization. However, water atomized powder has a lower cost despite higher oxygen levels and irregular particle shapes.

Q: Is Alloy X-750 powder compatible with 3D printing methods?

A: Yes, Alloy X-750 shows excellent processing behavior with powder bed fusion and directed energy deposition additive manufacturing. Parameters need optimization to achieve high density and properties.

Q: Does Alloy X-750 powder require special handling precautions?

A: Protective measures are advised due to the fine particle size distribution. Use appropriate personnel protective equipment, minimize dust generation via local exhaust ventilation, avoid ignition sources, and frequently clean equipment.

Q: What heat treatments are used on HIPped Alloy X-750 powder?

A: Solution annealing followed by multiple step aging treatments allow precipitation strengthening for enhanced strength levels along with stability at elevated temperatures.

Q: What is the typical surface finish achieved in metal injection molding with Alloy X-750 powder?

A: MIM processing permits surface finishes around Ra 0.1 μm (4 μin) directly after sintering. This allows many components to bypass finishing steps.

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