A2 is an air-hardening cold-work tool steel with about 1% carbon and 5% chromium. It hardens in air to about 57–62 HRC with very little distortion, and is tougher than D2 though less wear resistant. It is used for blanking and forming dies, punches, gauges and shear blades where chipping is a bigger risk than wear.
Quick facts
- Type
- Air-hardening cold-work tool steel
- Carbon / chromium
- About 1% / 5%
- Hardness
- About 57–62 HRC
- Hardening
- From about 940–970 °C, cooled in air
- Distortion
- Low
- Toughness
- Better than D2
Equivalent grades
| Standard | Grade |
|---|---|
| AISI | A2 |
| DIN / EN | 1.2363 (X100CrMoV5) |
| JIS | SKD12 |
Equivalents are close, not identical. Name the grade and standard on the drawing.
A2, D2 or OHNS?
| A2 | D2 | OHNS (O1) | |
|---|---|---|---|
| Wear resistance | Good | Very high | Moderate |
| Toughness | Good | Lower | Good |
| Distortion in hardening | Low | Low | More (oil) |
| Cost | Medium | Medium | Lower |
Typical uses
- Blanking and forming dies
- Punches and inserts
- Thread-rolling dies
- Gauges
- Shear blades
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Questions
- A2 or D2 for punches?
- A2 where punches chip or break; D2 where they wear out from long runs in abrasive material.
- Does A2 need oil quenching?
- No, it hardens in still air, which keeps distortion low.
- Can A2 be wire cut after hardening?
- Yes, it is often hardened first and then wire cut and ground to size.
The figures on this page are typical values for guidance, written by Diemeco from standard engineering practice. They are not a specification: confirm grades and properties with the relevant standard or the supplier's mill test certificate, and tolerances with your workshop. Last checked 23 October 2026.