Engineering Reference
Hardness Conversion Reference — HRC / HB / HV Quick Lookup
Conversion Notes
Hardness conversions between different test methods are empirical approximations. Actual values may vary due to material composition, heat treatment condition, and test conditions. Data is based on ASTM E140 and ISO 18265 standards, applicable to carbon steels, alloy steels, and tool steels. For critical acceptance, use the specific hardness test method agreed in the contract.
Hardness Conversion Quick Lookup
For carbon steels, alloy steels, tool steels (non-austenitic)| Rockwell HRC | Vickers HV | Brinell HB | Tensile Strength ≈ (MPa) | Typical Materials / Applications |
|---|---|---|---|---|
| 20 | 226 | 225 | 720 | Pre-hardened plastic mold steel (P20, NAK80) |
| 25 | 255 | 251 | 830 | Q&T structural steel (40Cr, 42CrMo) |
| 30 | 289 | 283 | 950 | Pre-hardened mold steels, shaft parts |
| 35 | 329 | 320 | 1080 | Quenched & tempered medium-carbon steel |
| 40 | 377 | 365 | 1240 | Hot work mold steel (H13/SKD61) service hardness |
| 45 | 436 | 420 | 1420 | Cold work mold steel (Cr12MoV) service hardness |
| 50 | 509 | 488 | 1640 | Cold work mold steel — high hardness use |
| 55 | 599 | 560 | 1920 | High-speed steel, high-wear cold work steel |
| 58 | 664 | 615 | 2100 | Guide pillars & bushings, bearing steel (SUJ2/GCr15) |
| 60 | 720 | 650 | 2280 | High-wear mold components, cutting tools |
| 62 | 780 | 688 | 2450 | Premium wear parts, precision mold inserts |
| 64 | 840 | 722 | 2620 | Extreme hardness, specialized wear applications |
Hardness Requirements for Common Mold Components
| Part Type | Recommended Hardness (HRC) | Common Materials | Notes |
|---|---|---|---|
| Guide Pillar | 58–62 | SUJ2 / GCr15 / 20Cr | Surface hardening + precision grinding |
| Guide Bushing | 58–62 | SUJ2 / GCr15 | Self-lubricating type may use copper alloy |
| Ejector Pin | 48–52 | SKD61 / H13 / SUJ2 | Nitriding can improve surface hardness |
| Return Pin | 58–62 | SUJ2 / GCr15 | Similar requirements to guide pillars |
| Sprue Bushing | 48–52 | SKD61 / H13 / S136 | Runner surface requires polishing |
| Slide / Lifter | 50–56 | H13 / SKD61 / D2 | Select based on application conditions |
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