3D Printing Metal Powder Series 2: Spherical 316L Stainless Steel Powder

In our previous article, we introduced Ti-6Al-4V titanium alloy powder. In this article, we are interested in exploring another common metal material applied in 3D printing—spherical 316L stainless steel powder. As one of the key materials for industrial-level additive manufacturing, spherical 316L stainless steel powder is of immense importance in the medical, aerospace, and chemical fields due to its comprehensive combination of properties.

1. Introduction to Stainless Steel Powder

Stainless steel powder is one of the most widely used materials in metal 3D printing. Stainless steel is a type of steel with a carbon (C) content below 2%, and above 2% is considered iron. During smelting, alloying elements such as chromium (Cr), nickel (Ni), manganese (Mn), silicon (Si), titanium (Ti), and molybdenum (Mo) are added to provide more desirable properties, including corrosion resistance,

Based on composition, stainless steel powder may be of various types, each with a number of traditional grades. Following is the list of some generic stainless steel grades:

Table 1. stainless steel types and grades

In order to be high in sphericity, low in oxygen, and possess good flowability, stainless steel powder is generally produced by gas atomization (GA) or plasma rotating electrode process (PREP). Compared to the traditional casting or forging, 3D printing grade stainless steel powder must have higher criteria:

• High sphericity (>95%) for optimal flowability and powder spreading homogeneity.
• Low oxygen content (<0.1%) to prevent oxidation-related defects in printing.
• Narrow particle size distribution (15-45μm) for process compatibility with processes such as selective laser melting (SLM).

2. Properties of Spherical 316L Stainless Steel Powder

Spherical 316L stainless steel powder consists of iron, chromium, nickel, molybdenum, low carbon, and trace amounts, with high corrosion resistance. Its advantages in additive manufacturing are:

• High corrosion resistance: Molybdenum (Mo) offers resistance to chlorides, seawater, and acid environments.
• High biocompatibility: Conforms to ISO 5832-1 and ASTM F138 standards, and thus can act as a medical implant.
• Good printability: Spherical powder offers high flowability and high laser absorption, reaching >99.5% part density.
• Moderate strength & ductility: Tensile strength ≥520 MPa, elongation ≥40%, which is good for intricate structures.

3. Why is 316L Better than 316 for 3D Printing

316 and 316L are both austenitic stainless steels but 316L stainless steel powder has a lower carbon content, which benefits 316L for 3D printing process:

• Resists intergranular corrosion: Continuous exposure to heat in printing may cause precipitation of Cr23C6 in 316, reducing corrosion resistance, but 316L avoids this.
• Reduced susceptibility to cracking: Carbon content is reduced, which decreases solidification cracking, especially in high-temperature processes like DED.
• Better interlayer bonding: 316L melt pool flow is less turbulent, reducing porosity in complex geometries.

4. Applications of Spherical 316L Stainless Steel Powder

As an industrial additive manufacturing base material, spherical 316L stainless steel powder is extensively used across many industries.

Medical & Biomedical Industries

The corrosion resistance and biocompatibility qualify 316L for surgical implant and device applications. Orthopedic devices like artificial joints, bone screws, spinal fixators and dental appliances like abutments, braces, surgical guides are commonly 3D-printed with 316L stainless steel powder for precision and tissue compatibility. High-tech applications include drug-eluting implants and optimized microporous stents for vascular applications.

Aerospace & Defense

With the need for light-weight, heat-resistant, and corrosion-resistant components such as fuel nozzles, heat exchangers, and turbine blades, 316L stainless steel powder is beneficial. 3D printing provides for complex internal passageways with retention of oxidation resistance.

Chemical & Energy Industries

Because of the resistance to corrosion by acids, alkalis, and H2S, 316L is used in pipelines, valves, pumps, and reactors. Complex path flow is allowed through 3D printing, making it more effective. Surface-modified 316L stainless steel is used in fuel cell bipolar plates for conductivity and corrosion resistance purposes in the energy industry.

Automotive Industry

Given lightweight and corrosion protection, heat/corrosion-resistant high-performance exhaust systems and EV battery packs use 3D-printed 316L for optimal designs.

Consumer Electronics

316L stainless steel’s smooth finish and hardness appeal to high-end casing applications (e.g., smartwatch bodies, phone frames) and functional components such as heat sinks to allow for integrated designs and better thermal management.

In the End

For tailored high-quality spherical 316/316L stainless steel powder for additive manufacturing, contact us for inquiries. SAM supplies high-purity gas-atomized powders with high sphericity, narrow particle size range, and low oxygen levels - well suited for SLM, DED, and other high-end 3D printing technologies.

In addition to stainless steel powders, we also offer titanium alloy powders, aluminum alloy powders, high-entropy alloy powders, nickel-based superalloy powders, and more.