Best inconel 718 powder for 3D printing

Overview of Inconel 718 Powder

Inconel 718 is a precipitation hardenable nickel-based superalloy powder widely used for additive manufacturing across aerospace, oil & gas, power generation and automotive industries. This article provides a detailed guide to Inconel 718 powder.

Key aspects covered include composition, properties, AM print parameters, applications, specifications, suppliers, handling, inspection methods, comparisons to alternatives, pros and cons, and FAQs. Tables are used to present information in an easy-to-reference format.

Composition of Inconel 718 Powder

The composition of Inconel 718 is:

Element	Weight %	Purpose
Nickel	50 – 55	Principal matrix element
Chromium	17 – 21	Oxidation resistance
Iron	Balance	Solid solution strengthener
Niobium	4.75 – 5.5	Precipitation hardening
Molybdenum	2.8 – 3.3	Solid solution strengthening
Titanium	0.65 – 1.15	Carbide former
Aluminum	0.2 – 0.8	Precipitation hardening
Carbon	0.08 max	Carbide former

Trace amounts of cobalt, boron, copper and magnesium are also added to enhance properties.

Properties of Inconel 718 Powder

Key properties of Inconel 718 include:

Property	Description
High strength	Tensile strength 1050 – 1350 MPa
Phase stability	Retains strength after prolonged use up to 700¡«C
Corrosion resistance	Resistant to aqueous corrosion and oxidation
Weldability	Readily weldable with matching filler
Fabricability	Easy to form and machine
Creep resistance	High stress rupture strength at high temperatures

The properties make Inconel 718 suitable for the most demanding applications.

AM Print Parameters for Inconel 718 Powder

Typical parameters for printing Inconel 718 powder include:

Parameter	Typical value	Purpose
Layer height	20 – 50 Ã×m	Balance speed and resolution
Laser power	195 – 350 W	Sufficient melting without evaporation
Scan speed	700 – 1300 mm/s	Density versus build rate
Hatch spacing	80 – 160 Ã×m	Mechanical properties
Support structure	Minimal	Easy removal
Hot isostatic pressing	1120¡«C, 100 MPa, 3h	Eliminate internal voids

The parameters depend on factors like build geometry, temperature management and post-processing needs.

Applications of 3D Printed Inconel 718 Parts

Inconel 718 parts made by AM are used in:

Industry	Components
Aerospace	Turbine blades, disks, hot section parts
Oil & gas	Downhole tools, valves, pumps
Power generation	Combustion cans, transition ducts
Automotive	Turbocharger wheels, exhaust valves
Medical	Orthopedic implants, surgical tools

Benefits over wrought parts include complex geometries and reduced buy-to-fly ratios.

Specifications of Inconel 718 Powder for AM

Inconel 718 powder must meet the following specifications for 3D printing:

Parameter	Specification
Particle size range	10 – 45 Ã×m
Particle shape	Spherical morphology
Apparent density	> 4 g/cc
Tap density	> 6 g/cc
Hall flow rate	> 23 sec for 50 g
Purity	>99.9%
Oxygen content	<100 ppm

Custom size distributions and controlled composition available.

Suppliers of Inconel 718 Powder

Prominent Inconel 718 powder suppliers include:

Supplier	Location
Praxair	USA
Carpenter Powder Products	USA
Sandvik Osprey	UK
LPW Technology	UK
Erasteel	France
AP&C	Canada

Prices range from $50/kg to $150/kg, influenced by quality and order quantity.

Handling and Storage of Inconel 718 Powder

As a reactive material, Inconel 718 powder requires controlled handling:

• Store sealed containers in a cool, dry inert atmosphere
• Prevent exposure to moisture, air, temperature extremes
• Use properly grounded equipment during transfer
• Avoid dust accumulation and ignition sources
• Local exhaust ventilation recommended
• Follow applicable safety guidelines

Correct storage/handling prevents composition changes or hazards.

Inspection and Testing of Inconel 718 Powder

Inconel 718 powder batches are validated using:

Method	Parameters Tested
Sieve analysis	Particle size distribution
SEM imaging	Particle morphology
EDX	Chemistry and composition
XRD	Phases present
Pycnometry	Density
Hall flow rate	Powder flowability

Testing per ASTM standards ensures batch-to-batch quality consistency.

Comparing Inconel 718 to Alternative Superalloy Powders

Inconel 718 compares with other alloys as:

Alloy	Cost	Printability	Weldability	Strength
Inconel 718	Low	Good	Excellent	Medium
Inconel 625	Medium	Excellent	Excellent	Low
Inconel 939	Very High	Fair	Limited	Excellent
Haynes 282	High	Good	Limited	Excellent

For balanced properties at lower cost, Inconel 718 supersedes other Ni superalloys for many applications.

Pros and Cons of Inconel 718 Powder for AM

Pros	Cons
Proven material credentials in AM	Lower high temperature strength than some alloys
Excellent weldability and machinability	Susceptible to solidification cracking during printing
Readily printed into complex shapes	Requires controlled atmosphere handling
Cost advantage over exotic superalloys	Significant post-processing often required
Available from range of suppliers	Relatively low hardness after printing

Inconel 718 enables high performance AM at a reasonable cost.

Frequently Asked Questions about Inconel 718 Powder

Q: What particle size range works best for printing Inconel 718 alloy?

A: A range of 15-45 microns provides the optimum combination of flowability, high resolution, and high density parts.

Q: What post processing is typically required for Inconel 718 AM parts?

A: Hot isostatic pressing, heat treatment, and machining are commonly needed to eliminate voids, optimize properties, and achieve tolerances.

Q: Is Inconel 718 easier to 3D print than other Ni superalloys?

A: Yes, its excellent weldability and lower cracking susceptibility make Inconel 718 one of the easier Ni-based superalloys to process by AM.

Q: What industries use Inconel 718 alloy for metal 3D printing?

A: Aerospace, oil & gas, power generation, automotive, and medical sectors are major applications benefiting from additively manufactured Inconel 718.

Q: Does Inconel 718 require supports when 3D printing?

A: Minimal supports are recommended on overhangs and bridged sections to prevent deformation and allow easy removal after printing.

Q: What defects can occur when printing Inconel 718 powder?

A: Potential defects are cracking, porosity, distortion, incomplete fusion, and surface roughness. Most can be prevented with optimized parameters.

Q: What hardness can be expected with Inconel 718 AM components?

A: Hardness after printing is typically 30-35 HRC. Post-processes like aging can increase it to 40-50 HRC for higher wear resistance.

Q: What accuracy can be obtained with Inconel 718 printed parts?

A: Comparable dimensional tolerances and surface finishes to CNC machined components can be achieved after post-processing.

Q: Is hot isostatic pressing mandatory for Inconel 718 3D printed parts?

A: HIP eliminates internal voids and improves fatigue life. It may not be required for non-critical applications.

Q: What alloy powder has properties closest to Inconel 718 for AM?

A: Inconel 625 has comparable corrosion resistance and weldability to 718 but lower strength. Inconel 939 trades weldability for higher strength.