Best in718 powder for 3D printing

Overview of IN718 Powder

IN718 is a precipitation hardenable nickel-based superalloy powder widely used for additive manufacturing, owing to its good strength, corrosion resistance, weldability and processability. This article provides a detailed guide to IN718 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 quantitative data in an easy-to-reference format.

Composition of IN718 Powder

The composition of IN718 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.

Properties of IN718 Powder

Key properties of IN718 include:

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

The properties make IN718 suitable for the most demanding applications.

3D Printing Parameters for IN718 Powder

Typical parameters for printing IN718 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 requirements.

Applications of 3D Printed IN718 Parts

IN718 parts made by AM are used in:

Industry	Components
Aerospace	Engine components like turbine blades, discs
Power generation	Combustion cans, transition ducts
Oil and gas	Downhole tools, valves, pumps
Automotive	Turbocharger wheels, exhaust valves
Medical	Orthopedic implants, surgical tools

Benefits over wrought IN718 include complex geometries, reduced lead times and buy-to-fly ratios.

Specifications of IN718 Powder for AM

IN718 powder must meet the following specifications for 3D printing:

Parameter	Specification
Particle size range	10 – 45 Ã×m
Particle shape	Spherical morphology
Apparent density	Typically > 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 tightly controlled composition available.

Suppliers of IN718 Powder

Prominent 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 considerations and order volumes.

Handling and Storage of IN718 Powder

As a reactive material, IN718 powder requires controlled handling:

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

Correct storage and handling prevents composition changes or hazards.

Inspection and Testing of IN718 Powder

IN718 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 IN718 to Alternative Superalloy Powders

IN718 compares with other alloys as:

Alloy	Cost	Printability	Weldability	Strength
IN718	Low	Good	Excellent	Medium
IN625	Medium	Excellent	Excellent	Low
IN792	High	Fair	Good	Excellent
IN939	Very High	Good	Limited	Excellent

For balanced properties at lower cost, IN718 supersedes other Ni-based superalloys for many applications.

Pros and Cons of IN718 Powder for 3D Printing

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

IN718 enables high performance additive manufacturing at a reasonable cost.

Frequently Asked Questions about IN718 Powder

Q: What particle size range works best for 3D printing IN718 alloy?

A: A range of 15-45 microns provides the optimum blend of flowability, high resolution, and high density parts. Finer powders below 10 microns can also be used.

Q: What post processing is typically required for IN718 AM components?

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

Q: Is IN718 easier to 3D print compared to other Ni superalloys?

A: Yes, the excellent weldability and lower susceptibility to cracking make IN718 one of the easier to process Ni-based superalloys by powder bed fusion techniques.

Q: What industries use IN718 alloy for metal 3D printing?

A: Aerospace, power generation, oil and gas, automotive, and medical sectors are major application areas for additively manufactured IN718 components.

Q: What material has properties closest to IN718 for AM?

A: IN625 alloy powder has comparable weldability and corrosion resistance to IN718 but lower strength. IN792 trades weldability for higher strength.

Q: Is hot isostatic pressing mandatory for IN718 3D printed parts?

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

Q: Does IN718 require support structures during 3D printing?

A: Minimal supports are recommended on overhangs and bridged sections to prevent deformation and facilitate easy removal post-printing.

Q: What defects can occur when printing with IN718 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 IN718 AM components?

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

Q: What precision can be obtained with IN718 printed parts?

A: After post-processing, IN718 printed components can achieve dimensional tolerances and surface finishes comparable to CNC machined parts.