Reviewed · 2026-08-13
Tool Steel
Tool steels are carbon and alloy steels engineered for dies, cutting tools, molds and other tooling where hardness must be balanced against toughness, dimensional control, thermal exposure and the chosen heat-treatment route.
Classification basis
Service temperature, dominant failure mode, hardening response and required surface or dimensional quality
A procurement-oriented guide to five tool-steel systems, separating wear-led cold-work grades from hot-work, high-speed, shock-resisting and mold-service requirements.
A familiar grade name never replaces the governing product specification and certified documentation.01
Explore subcategories
Cold-Work Tool Steel
Use this group for room-temperature forming and cutting loads; it does not cover sustained red-heat cutting, die-casting heat cycling or mold-surface requirements as the primary selection driver.
→Tool steelHot-Work Tool Steel
This category is driven by cyclic thermal and mechanical loading in forging, extrusion and die casting; cold-work wear rankings alone do not predict hot-tool life.
→Tool steelHigh-Speed Steel
Use for cutting edges where red hardness and wear at speed control performance; it is not a generic substitute for tougher shock tools or large hot-work dies.
→Tool steelShock-Resisting Tool Steel
This family addresses impact-led failure at moderate temperature; it should not be ranked by D-series abrasion performance or high-speed red hardness.
→Tool steelMold Steel
This procurement category includes prehardened and corrosion-resistant mold stock; it excludes die steels selected chiefly for hot-metal contact or cutting-edge wear.
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Representative grades and systems
| Grade / system | Use as a selection entry point |
|---|---|
| D2 | Identify whether abrasive wear, impact or heat checking controls life. |
| A2 | Match section size and hardening route to achievable through-hardness and distortion. |
| O1 | Specify cleanliness, machining allowance and surface quality where polish or fatigue matters. |
| H13 | Identify whether abrasive wear, impact or heat checking controls life. |
| M2 | Match section size and hardening route to achievable through-hardness and distortion. |
| S7 | Specify cleanliness, machining allowance and surface quality where polish or fatigue matters. |
| P20 | Identify whether abrasive wear, impact or heat checking controls life. |
| 420 mold quality | Match section size and hardening route to achievable through-hardness and distortion. |
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Property framework
Working hardness and carbide-supported wear resistance
Fracture toughness and resistance to chipping
Tempering response, dimensional stability and thermal-fatigue resistance
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Common product forms
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Applications
- Blanking, forming and extrusion dies
- Cutting tools, punches and shear blades
- Plastic molds, die-casting tooling and hot-work inserts
- Identify whether abrasive wear, impact or heat checking controls life.
- Match section size and hardening route to achievable through-hardness and distortion.
- Specify cleanliness, machining allowance and surface quality where polish or fatigue matters.
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Standards and designation systems
ASTM A681 alloy tool steels
ASTM A600 high-speed tool steels
ASTM A686 carbon tool steels and applicable product requirements
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Procurement checklist
- State standard, grade and required delivery condition.
- Define dimensions, machining allowance, surface condition and decarburization limits.
- Agree heat-treatment responsibility, hardness range, testing location and certification.
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