Qualified Materials Expansion: Get to Know M300 Tool Steel

by | September 8, 2022 | Business Drivers

The Velo3D Sapphire family of printers are capable of printing in a variety of materials, which is why we’re always evaluating new ones to add to our growing list. The newest to join is M300 Tool Steel.

In this article, we examine the material’s properties, the challenges encountered when using conventional metal additive manufacturing (AM) systems to print in M300, and how Velo3D’s manufacturing technology is uniquely suited to printing with M300, specifically parts where fluids flow or parts that exchange heat.

A conformal cooled tooling insert of a working surface for high pressure die casting (as printed)

Material properties

M300 Tool Steel is an ultra-low carbon alloy with very high strength and hardness properties derived from intermetallic compounds rather than carbon content. The material is comprised mainly of nickel, with cobalt, molybdenum, and titanium as secondary intermetallic alloying metals.

One important characteristic of M300 is that it’s easily heat treated, with superior mechanical properties achieved after age hardening.

Specifically, M300 is heat-treatable using a simple thermal age-hardening process to obtain excellent hardness and strength. It’s also a hardenable steel with excellent machinability for many tooling applications (post-hardened to more than 50 HRC).

The material can also be CNC machined or polished for specific features.

M300 Material properties

  • High strength
  • High hardness
  • High fatigue strength
  • Good machinability
  • Heat resistance up to 900°F / 482°C


3D metal printing provides and exciting opportunity for the automotive industry to print parts used in tooling applications. Velo3D has already seen extensive interest in the alloy from automotive manufacturers for use in high-pressure die cast (HPDC) inserts, injection molding, and other types of tooling.

With metal AM, engineers can decrease turnaround time and open the design window for more complex and efficient conformal cooling channels.

However, high carbon tool steels such as H13 or M2, which are typically used in tooling and molding applications, are very difficult to process with conventional laser powder bed fusion (LPBF).

Unfortunately, conventional AM faces a Catch-22: most systems can only print channels at a 5-6mm diameter. Any larger and the channels see issues with downskin (top of channel) roughness that can potentially decrease part lifetimes through crack propagation.

For HPDC inserts, this limits the value that AM can generate with conformal cooling – a technique used to increase part lifetimes. This can cause engineers a real dilemma. Adding channels to cool the part can increase its lifetime but optimize them too much and the part begins to fail because of the channels.

In addition, sizing of part is a challenge. Many parts used in the automotive industry are larger than the build envelope of conventional AM printers.

The advantages of using the Velo3D end-to-end solution with M300 Tool Steel

Velo3D offers customers the opportunity for both improved performance through higher quality, large diameter channels with improved downskin roughness and a large format printer capable printing parts fitting a 600mm diameter by 1000mm in height.

With the addition of M300, Velo3D offers a comparable alternative in terms of mechanical properties (to H13 and M2), but with proven additive manufacturing suitability.

M300 combined with Velo3D’s printing capabilities enables improved cooling channel design that can increase the lifetime of the inserts.

Many tooling customers are looking for channels larger than 20mm – clearly a challenge for conventional AM. Channels up to 100mm have been printed on Velo3D systems, opening the design window for many new concepts.

Contact us today to learn how you can leverage the Velo3D end-to-end solution for your HDPC inserts using M300 Tool Steel.

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About the Author

Amir Iliaifar

Director of Content

Amir Iliaifar is the Director of Content at Velo3D where he oversees the production and distribution of Velo3D’s global digital content marketing initiatives. Prior to joining the company, Amir worked for a leading professional drone manufacturer, several SaaS companies, and as an automotive tech journalist. He holds a Master of Arts in Digital Communication from the University of North Carolina at Chapel Hill.