Pre-hardened plastic mould steel Typical grade: P20 / 1.2311 | Approximately 28–36 HRC | Approximately 29–34 W/m·K | Moderate | Low; requires protection in humid environments | Good; suitable for conventional milling and drilling | Large cores, cavities, mould bases and plates | General-purpose moulds for non-abrasive thermoplastics and medium production volumes |
Pre-hardened stainless mould steel Typical grade: 1.2083 / 420 stainless steel | Approximately 45–52 HRC after hardening | Approximately 20–25 W/m·K | Good | Good when properly heat-treated and polished | Fair to moderate; slower cutting and careful polishing are required | Cavities, cores and inserts exposed to moisture or corrosive resin | Medical, optical, food-contact and moulding applications using PVC or flame-retardant materials |
Hot-work tool steel Typical grade: H13 / 1.2344 | Approximately 44–52 HRC | Approximately 24–30 W/m·K | Very good | Low to moderate; surface treatment may be needed | Moderate; carbide tooling and controlled heat treatment improve results | High-wear cores, cavities and hot-runner components | Glass-filled polymers, high moulding temperatures and long production runs |
Maraging steel Typical grade: 18Ni maraging steel | Approximately 48–54 HRC after ageing | Approximately 20–25 W/m·K | Very good | Moderate; not equivalent to stainless steel | Good before ageing; considerably harder to machine after ageing | Precision inserts, thin ribs and components requiring high dimensional stability | High-precision moulds, complex textures and additive-manufactured inserts requiring post-machining |
Powder metallurgy tool steel Typical grade: high-chromium PM steel | Approximately 58–64 HRC | Approximately 20–30 W/m·K | Excellent | Low to moderate, depending on alloy composition and finish | Difficult; EDM, grinding and carbide tooling are commonly used | Replaceable wear inserts and high-abrasion cavity sections | Glass-fibre, mineral-filled or flame-retardant compounds with severe abrasive wear |
Beryllium copper alloy Typical grade: CuBe2 | Approximately 35–44 HRC after age hardening | Approximately 105–130 W/m·K | Moderate to good | Good in typical moulding environments | Good, although machining dust requires strict occupational controls | Cooling inserts, cores and hot-spot sections | Deep ribs, bosses and areas where rapid heat removal reduces cycle time or warpage |
Copper alloy without beryllium Typical grade: precipitation-hardened Cu-Ni-Si or Cu-Cr-Zr | Approximately 28–45 HRC, depending on alloy and treatment | Approximately 150–300 W/m·K | Moderate | Good | Good to very good | Thermal inserts and conformal-cooling components | Applications requiring high heat transfer while avoiding beryllium exposure |
Tungsten carbide Typical grade: cemented carbide | Approximately 1,000–1,700 HV | Approximately 50–110 W/m·K, depending on binder content | Excellent | Good in most polymer-processing environments | Poor by conventional methods; grinding and EDM are typical | Small wear inserts, gates, valve seats and high-pressure sealing areas | Extremely abrasive compounds, high-volume production and erosion-prone details |
Tool steel with surface coating Typical treatment: nitriding, PVD or duplex treatment | Base steel typically 40–60 HRC; coated surface may exceed 1,000 HV | Usually close to the base steel; thin coatings have limited thermal effect | Very good to excellent, depending on coating and counterface | Improved surface protection, but coating defects can expose the substrate | Machining is performed before coating; repair and recoating require process control | Cores, cavities and inserts requiring lower friction or improved release | Abrasive resins, sliding details, difficult-release parts and extended maintenance intervals |