Stainless Steel 316L Powder for Metal 3D Printing

Overview

Stainless steel 316L powder is a type of stainless steel powder that contains molybdenum and has low carbon content. It is an austenitic chromium-nickel stainless steel that exhibits high strength and excellent corrosion resistance properties. 316L powder is widely used for 3D printing or additive manufacturing applications across industries such as aerospace, medical, automotive, and general manufacturing.

Some key properties and characteristics of 316L powder include:

Composition: Iron, chromium, nickel, molybdenum, manganese, silicon, carbon, phosphorus, sulfur

Particle Shape: Spherical, high flowability

Particle Size: 15-45 microns, submicron sizes available

Density: Approx 7.9 g/cc

Melting Point: 1381-1400°C

Key Features: Corrosion resistance, heat resistance, weldability, strength, biocompatibility

Common Trade Names: 316L, 1.4404, 1.4435

316L powder can be used to print strong and durable parts with complex geometries using various 3D printing processes like selective laser sintering (SLS), direct metal laser sintering (DMLS), electron beam melting (EBM), binder jetting, etc.

Types of 316L Powders

There are a few main types of 316L stainless steel powders available:

Gas Atomized 316L Powder

• Produced using inert gas atomization process
• Spherical particles with smooth surface
• Flows easily, packs densely for printing
• Good spreadability and compaction
• Used widely for laser-based and binder jet 3D printing

Water Atomized 316L Powder

• Made using high pressure water jets
• Irregular particle shape
• Porous surface, high oxygen content
• Lower cost compared to gas atomized powder
• Used mostly for press-and-sinter applications

Plasma Atomized 316L Powder

• Manufactured with plasma atomization
• Very spherical particles
• Controlled particle size distribution
• Used in critical applications requiring high density
• Expensive compared to other atomization methods

Recycled 316L Powder

• Recovered unused powder from 3D builds
• May have mixed particle shapes and sizes
• Needs additional sieving and processing
• Lower cost option for non-critical applications
• Concerns over contamination from prior builds

316L Powder Composition

316L stainless steel gets its corrosion resistance from chromium and molybdenum alloyed with iron. Here is the elemental composition of 316L powder:

The low carbon content reduces carbide precipitation during welding and enhances corrosion resistance. The addition of molybdenum boosts pitting and crevice corrosion performance in chloride environments.

The composition conforms to national and international grades like UNS S31603, W.Nr 1.4404, AISI 316L, and ISO 5832-1. Custom alloys are also possible for specialized requirements.

Key Properties and Characteristics

316L powder possesses a unique combination of outstanding properties which makes it suitable for various critical, high performance applications across industries.

Corrosion Resistance Excellent resistance to pitting, crevice corrosion, and stress corrosion cracking in acids, alkalis, salts, and organic chemicals

Mechanical Properties High ultimate tensile and yield strength coupled with good ductility and impact strength

Heat Resistance Can withstand continuous service up to ~900°C and intermittent exposure beyond for certain applications

Weldability Readily weldable and less prone to sensitization during welding compared to unstabilized grades

Bio-compatibility Non-toxic with high biocompatibility for use in medical implants and devices

Here is a table comparing the key properties of 316 vs 316L powder:

The superior corrosion resistance of 316L powder can be attributed to the higher PREN and lower carbon content compared to 316 powder. 316L also offers better bio-compatibility and is used preferentially for permanent implants in the human body.

Applications of 316L Powder

Some of the common applications where 316L powder finds widespread use include:

Additive Manufacturing SLS/DMLS/EBM printing of end-use metal parts across aerospace, medical, automotive, tooling etc.

Biomedical Implants Manufacturing implants like knee and hip replacements, spinal rods, dental fixtures etc.

Food Processing Equipment Valves, fittings, fasteners, machine parts for the food and pharmaceutical industries

Chemical Processing Industry
Pump impellers, housings, valve bodies and other wetted components

Marine Applications
Shafts, fittings, couplings, flanges, propellers used in marine environments

316L provides exceptional performance across this wide spectrum of applications owing to its outstanding corrosion resistance coupled with high strength.

Here are examples of some 316L parts printed using additive manufacturing:

316L Powder Specifications

316L powder used for AM needs to conform to, or exceed, the following specifications:

Particle Size Distribution

Apparent Density Typically 4.0-4.8 g/cc

Flow Rate
Hall flowmeter > 15 sec/50g

Chemical Composition As per 316L grade specifications aforementioned

Microstructure
Fully austenitic, absence of stringers and satellites

Particle Shape Predominantly spherical morphology

Surface Texture Smooth surface finish on particles

Oxygen Content Mostly <1000 ppm

Saturation Magnetization < 3.1 emu/g

Reputable 316L powder manufacturers produce material that meets or surpasses these specifications for AM. Every batch comes with a Certificate of Analysis from independent testing.

316L Powder Suppliers

Some leading global suppliers of 316L stainless steel powder include:

Custom alloys with special particle size distributions or tighter chemistry controls can cost 20-50% more than standard 316L powder compositions.

As for pricing, gas atomized 316L powder suitable for AM typically costs between $30-150 per kg depending on quality, batch size and geographic region. Water atomized and plasma atomized grades occupy the lower and upper ends of this range