M300 maraging steel powder (18Ni300, material number 1.2709) is the most common LPBF steel for precision tooling: injection mold inserts, core inserts with conformal cooling, and compact production fixtures. It is chosen when the tool needs high strength and hardness after aging, good dimensional recovery and internal geometry that drilling cannot reach — and when the duty is not dominated by severe hot-work cycling.
Already know the grade? See the M300 powder specification and price or request an M300 quote.
Where M300 fits
| Tool component | What AM adds | What to define for acceptance |
|---|---|---|
| Injection mold insert / core insert | Cooling channels close to the cavity, compact geometry | Aging response, distortion, polishing, channel integrity, datum machining |
| Conformal-cooled production tool | More uniform cooling and cycle stability | Coolant, pressure and leak test, powder removal from channels, cleaning |
| Mold slider or lifter | Internal cooling in a moving side action | Wear and guiding surfaces, impact, replacement — see the M300 slider and lifter guide |
| Production fixture, gripper or jig | Integrated locating and clamping features | Stiffness, contact wear, threads and inserts — see M300 robot gripper jaws |
The common pattern: geometry matters, insert performance matters, and the thermal load is real but not severe enough to force a hot-work steel.
M300 or H13?
The choice follows the thermal duty, not the steel name.
- M300 when the tool values post-aged strength, precision, polishability and dimensional stability — typical plastic injection molds and fixtures.
- H13 when repeated thermal cycling and heat checking dominate — die casting and hot-work tools. See H13 tool steel powder.
- Corrosion-resistant alternatives such as 12Cr9Ni maraging stainless or 420 stainless when coolant or polymer chemistry makes rust a problem. See the 12Cr9Ni and 420 grade pages.
For a side-by-side decision, use the H13 vs M300 powder guide.
Powder and aging route
Maraging steel reaches its hardness through aging after the build, so the purchase specification must connect the powder lot to the thermal route:
| Field | Define before approval |
|---|---|
| Grade | Exact M300 / 18Ni300 chemistry and governing specification |
| Powder | Atomization route, lot, PSD and method, morphology, contamination, packaging and reuse state |
| Build | Machine, parameter set, supports, stress relief and distortion strategy |
| Aging | Final aging condition, hardness or strength target, dimensional allowance |
| Tool | Cooling channels, machining and polishing, wear surfaces, leak and pressure test, inspection |
Do not compare as-built data with aged tool requirements. Ask which condition, machine, orientation, density and test method sit behind any typical value. Powder documents — lot COA, PSD report, SDS, and SEM where agreed — support powder acceptance; they do not prove tool life or cycle-time reduction, which need the final cooling design and a production trial.
RFQ fields
State the tool function, M300 specification, machine and process, target PSD, quantity, channel geometry and coolant, pressure or leak requirement, aging condition and hardness target, machining and polishing route, inspection plan and required documents. Send an M300 powder inquiry.