H13 Hot-Work Tool Steel

Material Profile: H13 Hot-Work Tool Steel for Binder Jetting

Binder Jetting Engineering Material Technical Report Series

Compiled from manufacturer technical datasheets and peer-reviewed literature

Abstract—AISI H13 is the dominant chromium-molybdenum-vanadium hot-work tool steel and a customer-qualified material on the Desktop Metal X-Series binder jet platform. Its principal binder-jet application is injection-mould inserts and die-casting tooling with conformal cooling channels — geometries impossible to produce by conventional gun-drilling but trivial via AM. As-sintered binder-jet H13 achieves HRC 38–42; double-tempered (austenitise 1010 °C, double-temper 540–600 °C) gives HRC 44–52 and preserves hot hardness up to ~ 600 °C. Conformal-cooling H13 inserts produced by binder jetting on the X160Pro (800 × 500 × 400 mm envelope) routinely cut injection-mould cycle times by 20–40 % and increase tool life through more uniform thermal control of the cavity surface.

Index Terms—additive manufacturing, binder jetting, H13, tool steel, hot-work, mould inserts, conformal cooling, AISI H13.

I.  MATERIAL IDENTIFICATION

This section establishes the canonical names and commercial designations under which the material is supplied.

A.  Designation

Trade names: Desktop Metal H13 (X-Series customer-qualified, Studio System); ExOne H13; Digital Metal DM H13. Wrought equivalents: ASTM A681 (UNS T20813), DIN 1.2344 / X40CrMoV5-1, JIS SKD61. Considered the global standard for hot-work tool steel.

B.  Full Chemical Name

Chromium-molybdenum-vanadium air-hardening hot-work tool steel. Composition (wt%): Cr 4.75–5.50, Mo 1.10–1.75, V 0.80–1.20, Si 0.80–1.20, Mn 0.20–0.50, C 0.32–0.45, P ≤ 0.030, S ≤ 0.030, Fe — balance. Strengthening mechanisms: (1) tempered martensite, (2) MC carbides (V₄C₃, ~ 1 µm) and M₆C carbides (Fe-Mo-rich), (3) secondary hardening peak at 540 °C on tempering due to fine V/Mo carbide precipitation.

C.  Aliases and Alternative Designations

II.  COMPOSITION AND MOLECULAR STRUCTURE

A.  Empirical Chemical Formula

Fe(balance) — Cr(4.75–5.50%) — Mo(1.10–1.75%) — V(0.80–1.20%) — Si(0.80–1.20%) — C(0.32–0.45%) — minor (Mn, P, S). Strengthening: tempered martensite + MC (V₄C₃) and M₆C (Fe-Mo) carbides + secondary hardening peak at 540 °C.

Fig. 1.  Repeating unit / structural schematic of the polymer matrix.

Fig. 2.  Schematic of the single-phase polymer (no reinforcement).

B.  Composition Breakdown

TABLE I
 COMPOSITIONAL BREAKDOWN OF H13 TOOL STEEL (DESKTOP METAL X-SERIES) (TYPICAL / PER SUPPLIER DATASHEET)

III.  MECHANICAL PROPERTIES — XY BUILD DIRECTION (HORIZONTAL)

In the XY orientation the tensile load is applied parallel to the powder-bed plane. Binder-jetted (BJ) parts in the as-sintered state generally show modest in-plane vs build-axis anisotropy because sintering occurs near the solidus and re-distributes the porosity left by the binder-removal step. For metal BJ, post-sintering treatments (HIP, solution-anneal, age) are commonly applied to bring properties to wrought-equivalent and to eliminate residual closed porosity.

TABLE II
 MECHANICAL PROPERTIES — XY ORIENTATION (H13 TOOL STEEL (DESKTOP METAL X-SERIES))

IV.  MECHANICAL PROPERTIES — Z BUILD DIRECTION (VERTICAL)

In the Z orientation the tensile load is applied perpendicular to the printed layers. Binder-jet metal parts typically exhibit Z-direction strength within 5–15 % of XY in the as-sintered state, since the inter-layer interface effectively dissolves during high-temperature sintering. For sand-mould materials, Z-direction strength is dominated by inter-layer binder bonding and is generally 60–90 % of XY in transverse strength.

TABLE III
 MECHANICAL PROPERTIES — Z ORIENTATION (H13 TOOL STEEL (DESKTOP METAL X-SERIES))

Binder-jet H13 is essentially isotropic after high-temperature sintering and Q&T heat treatment. The austenitisation at 1010 °C followed by air-quench produces a uniform martensitic microstructure independent of build orientation. Double-tempering at 540 °C / 2 h × 2 cycles ensures full carbide precipitation and dimensional stability for tooling applications.

V.  RECOMMENDED PROCESS PARAMETERS

Values summarised below give consensus operating windows from public datasheets (Desktop Metal, ExOne, voxeljet, cprint3d). Specific machines and parameter sets may differ within ±10 %; the supplier's verified parameter sheet always supersedes this table. For metal binder jetting, complete green-state cure (~200 °C) and a high-temperature de-bind / sinter cycle (typically 1 100–1 380 °C in H₂ / Ar / vacuum) are mandatory after print. For sand binder jetting, parts are usable directly after print (with optional microwave or oven post-cure).

TABLE IV
 RECOMMENDED BINDER-JETTING PROCESS PARAMETERS FOR H13 TOOL STEEL (DESKTOP METAL X-SERIES)

VI.  GLASS TRANSITION TEMPERATURE (TG)

Reported / typical Tg: Not applicable (metallic alloy).

Critical thermal limits: austenitisation 1010 °C (Ac₁ ≈ 860 °C, Ac₃ ≈ 915 °C); martensite start Ms ≈ 310 °C; secondary hardening tempering peak at 540 °C; service-temperature limit ≈ 540 °C continuous (above this, tempering progresses and hardness drops); melting range 1410–1460 °C.

VII.  HEAT DEFLECTION TEMPERATURE (HDT)

Heat deflection temperature is the temperature at which a standard bar deflects 0.25 mm under a specified flexural load (ASTM D648 / ISO 75).

TABLE V
 HEAT DEFLECTION TEMPERATURE OF H13 TOOL STEEL (DESKTOP METAL X-SERIES) UNDER STANDARD TEST LOADS

VIII.  DISTINGUISHING CHARACTERISTICS AND STANDARDS

A.  Conformal cooling — the killer application

Traditional injection-mould cooling channels are gun-drilled straight bores — they cannot follow the cavity geometry. Binder-jet H13 lets engineers route channels 1–3 mm beneath the cavity surface, parallel to its contour, dramatically improving cooling uniformity. Documented case studies (BMW, Whirlpool, Danfoss) show 20–40 % cycle-time reduction and 2–3× tool life increase.

B.  Hot hardness preserved to ~ 600 °C

Vanadium and molybdenum carbides (MC + M₆C) resist over-aging at die-casting / hot-forging temperatures. Hot hardness at 540 °C ≈ HRC 35 (vs HRC 20 for D2 or A2 cold-work tool steels) — the reason H13 has dominated hot-work tooling for 60 years.

C.  Superior thermal-fatigue resistance

Fine MC carbides and good through-hardenability give H13 exceptional thermal-fatigue resistance — critical for die-cast moulds that experience 100 000+ thermal cycles between hot metal injection and water-spray cooling. Binder-jet H13 inserts achieve thermal-fatigue performance equivalent to wrought H13 after Q&T.

D.  Air-hardening — minimal distortion

H13's air-quench hardenability eliminates oil or water quench, dramatically reducing distortion during heat treatment. Critical for thin-wall conformal cooling channels (~ 1 mm wall) which would crack under aggressive water quench.

E.  Customer-qualified vs fully qualified

On Desktop Metal X-Series, H13 is 'customer-qualified' rather than fully Desktop-Metal-qualified — meaning print parameters and sinter recipes have been demonstrated by individual customers but Desktop Metal does not yet publish a formal material datasheet. Full qualification expected during 2025–2026 as adoption grows.

IX.  REPRESENTATIVE APPLICATIONS

H13 Tool Steel (Desktop Metal X-Series) is typically deployed in the following applications:

1)  Injection-mould inserts with conformal cooling: Front-line application: tool inserts for plastic injection moulding where cycle time and cavity-surface uniformity drive part quality.

2)  Die-casting dies (aluminium, magnesium): Aluminium die-cast moulds for automotive structural parts; Mg die-cast for aerospace housings — H13 hot hardness essential.

(Source : GSC-3D)

3)  Hot-forging dies (small to medium): Open and closed die forging tooling for steel and Cu alloys, leveraging H13's thermal-fatigue resistance.

4)  Extrusion dies (Al): Aluminium extrusion bridge / mandrel tooling, especially for complex hollow sections requiring conformal cooling.

5)  Plastic mould bases and tooling components: Mould bases, ejector pins, slides where dimensional stability and toughness matter.

X.  REFERENCES

[1]  ASTM A681-08(2022), “Standard Specification for Tool Steels Alloy,” ASTM International, 2022.

[2]  DIN EN ISO 4957:2018, “Tool steels,” European Committee for Standardization.

[3]  Böhler Edelstahl, “W302 — Hot Work Tool Steel,” Technical bulletin.

[4]  Uddeholm, “Orvar Supreme — Hot-work Tool Steel,” Technical bulletin, 2022.

[5]  C. Mapelli et al., “Microstructural evolution of binder-jetted H13 tool steel,” Materials Science and Engineering A, vol. 829, 142124, 2022.

[6]  ASTM E8/E8M-22, “Standard Test Methods for Tension Testing of Metallic Materials,” ASTM International, 2022.

[7]  ASTM B962-17, “Standard Test Methods for Density of Compacted or Sintered Powder Metallurgy (PM) Products Using Archimedes' Principle,” ASTM International, 2017.

[8]  ASTM E18-22, “Standard Test Methods for Rockwell Hardness of Metallic Materials,” ASTM International, 2022.

[9]  ASTM F3318-22, “Standard for Additive Manufacturing — Finished Part Properties — Specification for AlSi10Mg with Powder Bed Fusion — Laser Beam,” ASTM International, 2022.

[10]  ISO/ASTM 52900:2021, “Additive manufacturing — General principles — Fundamentals and vocabulary,” ISO, 2021.

[11]  ISO/ASTM 52904:2024, “Additive manufacturing — Process characteristics and performance — Practice for metal powder bed fusion process to meet critical applications,” ISO, 2024.

[12]  MPIF Standard 35-MIM, “Materials Standards for Metal Injection Molded Parts,” Metal Powder Industries Federation, 2022 ed.

[13]  Desktop Metal, “Material Properties of Binder Jet Parts,” Desktop Metal Technical White Paper. [Online]. Available: https://www.desktopmetal.com/resources/material-properties-of-binder-jet-parts

[14]  Desktop Metal, “Why Binder Jetting?” Desktop Metal Application Note. [Online]. Available: https://www.desktopmetal.com/resources/why-binder-jetting-1

[15]  Desktop Metal, “Materials portfolio overview,” Desktop Metal product page. [Online]. Available: https://www.desktopmetal.com/materials/

(Image Source : Markforged)