H13 Tool Steel
metalchromium-molybdenum hot-work tool steel
AISI H131.2344 (DIN)X40CrMoV5-1 (EN)SKD61 (JIS)HS6-5-2 (partial equiv.)Tool Steel H13EOS Tool Steel H13
Composition — AISI H13 / DIN 1.2344 / EN X40CrMoV5-1
| Element | Min % | Max % | Notes |
|---|---|---|---|
| Fe | bal. | balance | |
| C | 0.32 | 0.450 | Carbon controls martensite hardness; higher C → harder martensite but reduced toughness. LPBF powder typically at lower end (~0.35%) for improved weldability. |
| Cr | 4.75 | 5.500 | Primary hardenability element; forms M₂₃C₆ and M₇C₃ carbides during secondary hardening (tempering) |
| Mo | 1.10 | 1.750 | Mo₂C formation during tempering (secondary hardening peak); significantly improves high-temperature strength and temper resistance |
| V | 0.80 | 1.200 | VC precipitates resist grain coarsening at austenitising temperature; primary driver of secondary hardening at 550–600°C temper |
| Si | 0.80 | 1.200 | Solid solution strengthener; improves oxidation resistance at elevated temperatures |
| Mn | 0.20 | 0.500 | |
| P | — | 0.030 | |
| S | — | 0.030 | Low S critical for toughness; minimises MnS inclusion formation |
| Ni | — | 0.300 |
Mechanical & thermal properties — 3 conditions
| Property | LPBF + Stress-relieved (550°C/2h, XY) | LPBF + Q+T Double Temper (44–48 HRC, XY) | LPBF + Q+T Double Temper (Z — build direction) |
|---|---|---|---|
| Elastic modulus | 210 GPa | 210 GPa | — |
| Yield strength (0.2%) | 1250–1450 MPa | 1200–1400 MPa | 1160–1360 MPa |
| Ultimate tensile strength | 1500–1700 MPa | 1380–1620 MPa | 1340–1580 MPa |
| Elongation at break | 2.0–6.0 % | 7.0–12.0 % | 6.0–10.0 % |
| Hardness (HV) | 520–620 HV10 | 440–510 HV10 | — |
| Density | 7.80 g/cm³ | 7.80 g/cm³ | — |
| Thermal conductivity | 22.0–27.0 W/m·K | — | — |
| CTE | 10.8–12.5 µm/m·K | — | — |
Values shown as min–max where a spread is reported, otherwise as typical ± unit. Ranges reflect inter-source variation, not single-sample scatter. All values are for AM-processed specimens unless noted.
Engineering considerations
- Conformal cooling design rules: minimum channel diameter 3 mm (surface roughness and thermal resistance); minimum channel-to-cavity wall distance 1.5× channel diameter; pitch 2.5–3× diameter for uniform cooling. Water flow velocity >0.5 m/s for turbulent flow (Re > 2300) — critical for heat transfer.
- Preheating protocol: 200°C minimum base plate preheat in the LPBF machine. EOS M 290/M 300 achieve this via base plate heater. Without preheat, delamination and through-cracks are almost certain at H13 carbon content.
- Post-LPBF sequence: LPBF (200°C preheat) → stress relief (550°C/2h, furnace cool) → rough machine → austenitise (1020°C/30–45 min vacuum) → polymer/oil quench → double temper (560°C/2h + 560°C/2h) → finish machine → surface treat (nitriding optional).
- Retained austenite: single-temper H13 retains 5–10% austenite which transforms to martensite during moulding service cycles, causing dimensional instability. Always double-temper.
- Surface treatment: LPBF H13 can be nitrided (plasma or gas) to achieve surface hardness of 900–1000 HV to ~0.1–0.2 mm depth. Improves abrasion resistance for glass-filled or mineral-filled polymer moulding. Nitriding temperature (480–530°C) must be below temper temperature to avoid softening.
- DED repair: for feature addition or worn cavity repair, use DED with ER431 or H13 powder wire. Post-DED temper at 560°C for 2h. Verify hardness and chemical composition in repair zone before return to service.
- Cooling channel inspection: internal channel quality from LPBF can be verified by flushing with pressure drop testing or borescope inspection. Surface Ra of ~12–20 µm in as-built channels is acceptable — turbulent flow insensitive to this roughness range.
- Dimensional stability: H13 expands ~0.06–0.08% on austenitising and contracts ~0.04–0.05% on tempering (net change ~+0.02–0.03%). Account for heat treatment dimensional change in LPBF near-net geometry or machine post-HT.
Advantages
- Primary AM use case: conformal cooling channels reduce injection mould cycle time 20–40% vs straight-drilled cooling
- Full Q+T cycle achieves conventional H13 properties — wrought-equivalent hardness (44–48 HRC) and toughness
- Good thermal fatigue resistance: Mo and V carbides resist thermal softening at mould service temperatures (150–350°C)
- Low anisotropy after Q+T — austenitising recrystallises LPBF columnar texture
- DED enables repair of worn conventional H13 tooling (cost 20–30% of replacement die)
- Rapid prototyping of complex die geometry without EDM lead time
Limitations
- Mandatory 200–250°C base plate preheating during LPBF — without preheat, through-layer hot cracks form due to high thermal gradient and hard martensite brittleness
- As-built and stress-relieved conditions are not serviceable — full Q+T cycle required for final tooling application
- High risk of hydrogen-induced delayed cracking if not properly stress-relieved before quench
- Austenitising temperature (1020°C) causes solution of fine LPBF carbides — some AM microstructural advantage is lost during HT
- Slower printing than austenitic stainless or aluminium — high carbon and chromium content create fine process window
- EDM after LPBF requires re-tempering: EDM creates a white layer (untempered martensite) which must be removed or re-tempered to prevent brittle fracture
- Not suitable for non-tooling structural applications — excessive hardness with low ductility in stress-relieved state
Typical applications
Injection moulding inserts with conformal cooling channelsDie casting tooling — H13 is the primary hot-work die steel globallyExtrusion dies and tooling for aluminium profilesForging dies and progressive stamping toolingHot-work tooling for glass and plastics processingAerospace forming tooling (superplastic forming, hydroforming)Repair and feature addition on worn conventional H13 tooling (DED process)Rapid tooling inserts for prototype injection moulding
Industries
toolingautomotiveindustrialaerospacedefence
Standards & certifications
Compatible AM processes (2)
Other metal materials
Ti-6Al-4V Grade 5titanium alloy — alpha-beta316L Stainless Steelaustenitic stainless steel17-4PH Stainless Steelmartensitic precipitation-hardening stainless steelAlSi10Mgaluminium-silicon alloy (cast grade adapted for AM)AlSi7Mg Aluminium Alloyhypoeutectic Al-Si-Mg precipitation-hardenable aluminium alloyInconel 718nickel superalloy — precipitation-hardenedInconel 625nickel superalloy — solid-solution-strengthenedCoCrMocobalt-chromium alloy (biomedical and aerospace grade)Maraging Steel MS1 (18Ni-300)maraging steel (ultra-high-strength, precipitation-hardened)
Related calculators
HT AdvisorStandard stress-relief, solution, and aging cycles for AM metals (Ti-6Al-4V, IN718, 17-4PH, AlSi10Mg, 316L, CuCrZr) per AMS, ASTM F3301, and AMS 5664.DistortionEstimate residual stress and distortion risk index (σ/σ_y) for LPBF and DED builds. Mercelis-Kruth model with preheat sensitivity table.VEDCompute LPBF VED from power, scan speed, hatch, and layer thickness. Includes process windows for common alloys.Conformal CoolingAM-enabled conformal cooling for injection moulds — heat transfer coefficient, Nusselt number (Dittus-Boelter), pressure drop (Darcy-Weisbach), and cycle time reduction vs. straight-drilled.
Last reviewed: 2026-05-05 · v1 · Sources: eos-h13-2023, spi-2005-h13, debroy-2018-review