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Tool Steel

H13 Tool Steel

H13 is the dominant hot-work tool steel, engineered to resist thermal fatigue, softening, and cracking at elevated temperature. With a 540 degrees C max-temp rating, 1650 MPa tensile, and a hardened ~50 HRC that resists tempering back, it endures the repeated heating and quenching cycles of die casting and forging that would destroy cold-work grades like A2 or O1.

How H13 Tool Steel machines

Machinability is 2.5/5 in the annealed condition. Machine H13 annealed, then heat treat. It cuts moderately with carbide; use rigid setups, sharp tooling, and steady feeds. After hardening to ~50 HRC, finishing is by grinding or EDM. Polishing matters for mold cavities, where surface defects seed heat-checking cracks.

Manufacturing & processing

Processed by CNC and forging. H13 is air or vacuum hardened to limit distortion and oxidation, then double or triple tempered to develop secondary hardness and stability at temperature. Surface treatments like nitriding are common to boost wear and erosion resistance on die and mold surfaces.

Typical applications

Best for hot-work dies and die-casting molds. Typical uses include aluminum and magnesium die-casting dies, forging dies, extrusion tooling, plastic injection molds, and hot-shear blades where parts cycle between high heat and cooling and must resist thermal-fatigue checking.

When to choose it

Choose H13 whenever tooling sees sustained or cyclic heat, especially die casting, forging, and extrusion. For cold-work blanking and forming, A2 or D2 give better wear at lower cost. H13's strength is heat resistance, not room-temperature wear.

Suitable surface finishes

Common finishes for H13 Tool Steel: black oxide, nickel plating. Use the finish selector →

FAQ

What makes H13 suitable for hot-work tooling?
Its chromium-molybdenum-vanadium chemistry resists tempering back and softening up to about 540 degrees C, and it withstands thermal fatigue. This lets dies endure the repeated heat-and-quench cycles of casting and forging without rapid heat-checking or cracking in service.
Why is H13 used for die-casting molds?
Die casting subjects tooling to molten metal contact and rapid thermal cycling. H13 resists the resulting thermal-fatigue cracking, called heat-checking, far better than cold-work steels, which gives substantially longer die life in aluminum and magnesium casting service.
Is H13 machined before or after heat treatment?
Machine H13 in the annealed condition, then harden and finish by grinding, EDM, and polishing. At its hardened ~50 HRC conventional cutting is impractical, and mold surfaces are polished to prevent crack initiation in service.

Property values are typical/nominal for early guidance and vary by temper, grade, supplier and heat treatment. Confirm critical specs against a certified datasheet or with an mfgiq engineer.