Reference · 16 grades
Tool steel grade reference
Equivalents, working hardness, machinability and what each grade is actually for. Free to use and free to link to — every grade has its own anchor.
| AISI | JIS | DIN / W.Nr. | GB | Family | HRC | Mach. | Quench | Distortion | Hard tooling |
|---|---|---|---|---|---|---|---|---|---|
| D2 | SKD11 | 1.2379 | Cr12MoV | Cold work | 58-62 | 52% | Air | Low | CBN |
| D3 | SKD1 | 1.2080 | Cr12 | Cold work | 58-64 | 45% | Oil | Moderate | CBN |
| A2 | SKD12 | 1.2363 | Cr5Mo1V | Cold work | 57-62 | 68% | Air | Very low | CBN or coated carbide |
| O1 | SKS3 | 1.2510 | 9CrWMn | Cold work | 57-62 | 75% | Oil | High | CBN or coated carbide |
| H13 | SKD61 | 1.2344 | 4Cr5MoSiV1 | Hot work | 44-52 | 72% | Air / Oil | Low | Coated carbide |
| H11 | SKD6 | 1.2343 | 4Cr5MoSiV | Hot work | 44-52 | 74% | Air / Oil | Low | Coated carbide |
| S7 | — | 1.2357 (approx.) | 6CrW2Si (approx.) | Shock resisting | 54-58 | 72% | Air / Oil | Low | Coated carbide |
| M2 | SKH51 | 1.3343 | W6Mo5Cr4V2 | High speed | 62-65 | 40% | Vacuum / Air | Low | CBN, or grind |
| M42 | SKH59 | 1.3247 | W2Mo9Cr4VCo8 | High speed | 65-68 | 35% | Vacuum / Air | Low | Grind |
| P20 | — | 1.2311 | 3Cr2Mo | Mould / pre-hardened | 28-34 | 70% | Pre-hardened | Very low | Coated carbide |
| P20+Ni | — | 1.2738 | 3Cr2MnNiMo | Mould / pre-hardened | 30-36 | 68% | Pre-hardened | Very low | Coated carbide |
| 4140 | SCM440 | 1.7225 | 42CrMo | Mould / pre-hardened | 28-32 | 62% | Pre-hardened | Very low | Coated carbide |
| 420 | SUS420J2 | 1.2083 | 4Cr13 | Stainless / bearing | 48-52 | 55% | Air / Oil | Low | CBN or coated carbide |
| 440C | SUS440C | 1.4125 | 11Cr17 | Stainless / bearing | 56-60 | 45% | Air / Oil | Low | CBN |
| 52100 | SUJ2 | 1.3505 | GCr15 | Stainless / bearing | 60-64 | 50% | Oil | Moderate | CBN |
| 17-4 PH | SUS630 | 1.4542 | 0Cr17Ni4Cu4Nb | Stainless / bearing | 35-44 | 55% | Pre-hardened | Very low | Coated carbide |
Grade by grade
What each one is for
D2SKD11 · 1.2379
- Working hardness
- 58-62 HRC
- Fails by
- Chipping
Used for: Blanking dies, forming tools, wear parts, thread rolls
Stocked widely in Vietnam as SKD11. Highest tooling cost to machine hard.
D3SKD1 · 1.2080
- Working hardness
- 58-64 HRC
- Fails by
- Chipping
Used for: Long-run blanking dies, draw dies, shear blades
Harder and more brittle than D2. Oil quench means more distortion — plan allowance.
A2SKD12 · 1.2363
- Working hardness
- 57-62 HRC
- Fails by
- Wearing, some chipping
Used for: Punches, forming dies, gauges, fixtures needing stability
The forgiving all-rounder. Choose over D2 wherever impact or misalignment is likely.
O1SKS3 · 1.2510
- Working hardness
- 57-62 HRC
- Fails by
- Wearing
Used for: Simple dies, form tools, spacers, low-volume tooling
Cheapest and easiest soft. The oil quench moves it 3-4x more than A2 — costs come back at finishing.
H13SKD61 · 1.2344
- Working hardness
- 44-52 HRC
- Fails by
- Thermal fatigue, heat checking
Used for: Die casting dies, extrusion tooling, hot forging dies, mould cores
The most widely stocked tool steel in Asia. Specify this where the design allows it.
H11SKD6 · 1.2343
- Working hardness
- 44-52 HRC
- Fails by
- Thermal fatigue
Used for: Hot work tooling needing more toughness than H13
Slightly tougher, slightly less hot-wear resistant than H13. Less commonly stocked.
S71.2357 (approx.)
- Working hardness
- 54-58 HRC
- Fails by
- Deforming
Used for: Heavy punches, chisels, shear blades, die holders, forming dies
No exact DIN equivalent in common circulation — expect import if shock performance is critical.
M2SKH51 · 1.3343
- Working hardness
- 62-65 HRC
- Fails by
- Chipping
Used for: Cutting tools, form tools, punches needing extreme wear resistance
At 64 HRC most features are ground, not milled. Budget accordingly.
M42SKH59 · 1.3247
- Working hardness
- 65-68 HRC
- Fails by
- Chipping
Used for: Cutting tools for difficult materials, high-wear punches
Cobalt-bearing. Above practical hard-milling range — treat as a grinding job.
P201.2311
- Working hardness
- 28-34 HRC
- Fails by
- Wearing, galling
Used for: Injection mould cavities and cores, mould bases, holder plates
No heat treat step at all. Supplied stress relieved. Nitride for extra wear life.
P20+Ni1.2738
- Working hardness
- 30-36 HRC
- Fails by
- Wearing
Used for: Large mould bases and cavity blocks over ~300 mm section
Nickel added for through-thickness uniformity. Use instead of 1.2311 on thick blocks.
4140SCM440 · 1.7225
- Working hardness
- 28-32 HRC
- Fails by
- Wearing, galling
Used for: Shafts, holders, die shoes, structural tooling
Excellent shaft and holder material. Not a cutting edge.
420SUS420J2 · 1.2083
- Working hardness
- 48-52 HRC
- Fails by
- Wearing
Used for: Corrosion-resistant mould cavities, medical and food tooling, optical moulds
Specify where the moulded resin is corrosive (PVC, flame-retardant grades) or polish is critical.
440CSUS440C · 1.4125
- Working hardness
- 56-60 HRC
- Fails by
- Chipping
Used for: Corrosion-resistant wear parts, bearings, valve components, knives
High carbide load makes it abrasive to machine — closer to D2 than to 420 in tooling cost.
52100SUJ2 · 1.3505
- Working hardness
- 60-64 HRC
- Fails by
- Spalling under rolling contact
Used for: Bearing races, rollers, precision spindles, gauge components
The classic hard-turning material. Surface integrity matters more here than anywhere else.
17-4 PHSUS630 · 1.4542
- Working hardness
- 35-44 HRC
- Fails by
- Galling
Used for: Corrosion-resistant fixtures, valve and pump parts, medical components
Precipitation hardened. Condition matters hugely — H900 machines very differently from solution annealed.
How to read this table
Machinability
Percentage of 1% carbon tool steel in the annealed condition. Below about 50% means insert consumption is a real line item on a quote, not a rounding error.
Distortion
How much the part moves in heat treatment. Drives the stock allowance you have to leave — see the allowance table.
Hard tooling
What it takes to cut at working hardness. "CBN" means the finishing operation carries real tooling cost; "grind" means milling is not the route.
Using this table elsewhere? Go ahead — it is published underCC BY 4.0. A link back to this page is the only condition. If a figure here looks wrong for your experience, say so and it gets corrected with the change noted.