Tool Steel Powder for Additive Manufacturing
Your guide to the two tool steels that define AM tooling: H13 for conformal-cooled hot-work dies, and 18Ni300 maraging steel for high-strength inserts. Compare compositions, heat treatment, printability, and find verified Chinese manufacturers.
1900 MPa
18Ni300 Aged UTS Class
480–520°C
18Ni300 Aging Window
15–53µm
LPBF Cut (H13)
53–150µm
DED Repair Cut (H13)
1. Tool Steel Grades — Hot-Work Dies or High-Strength Inserts?
AM changed toolmaking twice: it put conformal cooling channels inside dies, and it made the world's strongest printable steel a commodity. H13 and 18Ni300 are the two grades that carry most of that volume.
| Grade | Chemistry (wt%) | Key Feature | Primary Applications |
|---|---|---|---|
| H13 | Fe bal · C 0.32-0.45 · Cr 4.75-5.5 · Mo 1.1-1.75 · Si 0.8-1.2 · V 0.8-1.2 | Hot-work standard: hardenability + thermal fatigue resistance | Conformal-cooled die inserts, DED repair of failed molds |
| 18Ni300 | Fe bal · Ni 18-19 · Co 8.5-9.5 · Mo 4.5-5.2 · Ti 0.6-0.8 · C ≤0.03 | Carbon-free aging: print-soft, age-hard to ~1900 MPa class | Mold inserts, precision cores, aerospace fixtures, racing parts |
💡 Why these two work so well in AM: 18Ni300 strengthens by Ni/Co/Mo/Ti intermetallic precipitation instead of carbon — the as-printed low-carbon martensite is machinable, then a simple 480-520°C age-hardening reaches the 1900 MPa class, with no carburizing or surface hardening needed. H13 in contrast is a carbon-hardening hot-work steel: print with 15-53µm fine powder for dense LPBF inserts, or repair worn die surfaces with 53-150µm DED powder. Its as-printed structure is relatively brittle, so design the tempering schedule around your target hardness range — the same logic as wrought H13 toolmaking.
The two grades also complement each other in the same tool shop: 18Ni300 excels where dimensional precision after hardening matters most (aging shrinkage is small and predictable), while H13 carries the thermal-loading side of the mold — die casting, extrusion and injection tooling. Many Chinese moldmakers run both powders on the same LPBF fleet, switching by job.
2. Critical Quality Factors
Oxygen content: For 18Ni300, oxygen directly affects toughness and fatigue life — the premium maraging grades are sold on low-oxygen VIGA powder. Check the certificate value per lot.
Aging condition: 18Ni300 properties are meaningless without the aging schedule. 480-520°C is the common window; state your target hardness band and require aged tensile data (UTS/YS/elongation).
Particle-size cut by process: LPBF inserts use 15-53µm; DED repair uses 53-150µm. Buying the wrong cut wastes powder and changes process behavior.
Coupon validation: Before volume orders, print test blocks and verify hardness, density and — for H13 — thermal fatigue behavior. Die performance depends on the whole thermal cycle, not just the powder.
3. Applications by Grade
- Die casting, extrusion and injection molds: H13 inserts with conformal cooling — arbitrary-curvature channels shorten cycle times and reduce thermal-stress distortion versus drilled straight channels.
- Mold repair & remanufacturing: H13 DED cladding of failed die surfaces — the 53-150µm cut restores worn tooling at a fraction of replacement cost.
- Precision mold cores & inserts: 18Ni300 — printable, machinable in the soft state, then age-hardened with minimal distortion (aging shrinkage is small and predictable).
- Aerospace tooling and small-batch structural parts: 18Ni300 jigs, fixtures and high-strength lightweight components; racing and performance parts where the 1900 MPa class pays off.
4. China vs Global Supply
| Dimension | China | Global |
|---|---|---|
| H13 | GB/T 1299 (4Cr5MoSiV1), VIGA volume production | AISI H13 / JIS SKD61, mature tool-steel supply |
| 18Ni300 | VIGA low-oxygen grades; strong domestic mold demand | AMS 6514 / 1.2709 (MS1) heritage, certified aerospace programs |
| Conformal-cooling adoption | Rapid growth across die-casting and injection molding | Established in premium mold-making regions |
5. Patent Landscape (selected public filings)
Chinese tool-steel AM patents target arc/laser process control, defect reduction and die-application powder design. Public patent database, for technical reference only:
- CN121551633A — LPBF lattice-structure method for 18Ni300 gas-permeable mold steel (Dongguan University of Technology, 2025)
- CN118143286A — Reducing surface defects in SLM 18Ni300 steel (2024, granted)
- CN121109871A — Metal powder for high-thermal-conductivity die-casting mold AM (Central Iron & Steel Research Institute, 2025)
- CN122378192A — Improving CMT arc-DED H13 block structure and properties (Inner Mongolia Baotou Steel Union, 2026)
6. Buying Checklist
- ✓ Choose the cut by process: 15-53µm for LPBF, 53-150µm for DED repair.
- ✓ For 18Ni300: state your aging window (480-520°C common) and require aged UTS/YS/elongation data.
- ✓ For H13: define the target hardness band and match the tempering schedule.
- ✓ Check oxygen content and batch consistency — both grades are performance-sensitive to it.
- ✓ Validate with printed coupons: hardness, density, and thermal-fatigue behavior for H13.
Frequently Asked Questions
Why is 18Ni300 so printable compared with other high-strength steels?It hardens by intermetallic precipitation, not carbon. The as-printed carbon-free martensite is soft and machinable with low cracking tendency, and the 480-520°C aging then delivers the 1900 MPa class strength — no carburizing or quenching needed.
LPBF or DED for H13 mold work?LPBF for new conformal-cooled inserts (15-53µm, high density); DED for repairing worn die surfaces (53-150µm, faster deposition). Many tool shops use both routes in the same plant.
Does the aging treatment distort 18Ni300 parts?Aging shrinkage is small and predictable compared with quench hardening — that is one reason maraging steels suit precision mold inserts. Still, validate your part geometry through one full print-and-age cycle before series production.
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