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When choosing tool steel for knives, dies, or precision tools, O1 tool steel and A2 tool steel are among the most popular options. Both offer high wear resistance and toughness, but they differ significantly in terms of heat treatment, hardness, and performance.
In this guide, we compare O1 vs A2 steel in depth — helping you decide which is better for your application.
O1 tool steel (also written as 01 tool steel or O-1 steel) is a high-carbon, oil-hardening tool steel known for its excellent edge retention and dimensional stability. It is widely used in:
👉 Learn more about other cold work tool steel options in our article: Cold Work Tool Steel Grades: Properties & Applications
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.90–1.00 |
| Chromium (Cr) | 0.40–0.60 |
| Manganese (Mn) | 1.00–1.20 |
| Tungsten (W) | 0.50 |
| Vanadium (V) | 0.20 |
O1 steel heat treatment is straightforward and does not require vacuum or air quenching. It’s one reason why O1 tool steel is popular among small-scale knife makers.
Advantages:
Disadvantages:
A2 tool steel is an air-hardening, medium-alloy cold work steel offering a balance of wear resistance and toughness. It is commonly used in:
👉 Interested in impact-resistant tool steel? Check out our 5CrW2MoSiV Impact-Resistant Tool Steel designed for high-load applications.
| Element | Composition (%) |
|---|---|
| Carbon (C) | 1.00 |
| Chromium (Cr) | 5.00 |
| Molybdenum (Mo) | 1.00 |
| Vanadium (V) | 0.25 |
| Manganese (Mn) | 1.00 |
Because it is air hardening, heat treating A2 tool steel produces less distortion, making it ideal for precision tooling.
👉 For a detailed breakdown of thermal processing and material strength, visit our blog: 4Cr3Mo3SiV Hot Work Tool Steel Properties
| Property | Value |
|---|---|
| A2 tool steel hardness (after tempering) | 58–63 HRC |
| Hardness before heat treat | ~20 HRC |
| Yield Strength | ~2000 MPa |
| Toughness | High (better than O1) |
| Wear Resistance | Moderate to high |
| Corrosion Resistance | Slightly better than O1 |
| Feature | O1 Tool Steel | A2 Tool Steel |
|---|---|---|
| Hardening Method | Oil quench | Air hardening |
| Final Hardness | 57–62 HRC | 58–63 HRC |
| Machinability | Easier | Moderate |
| Distortion on Heat Treat | Moderate | Low |
| Wear Resistance | High | Moderate-High |
| Toughness | Moderate | High |
| Ideal for Knives? | ✅ Yes | ✅ Yes |
| Ideal for Tooling? | ✅ Yes | ✅ Yes |
| Best For | Custom knives, dies | Precision dies, larger tools |
O1 vs A2 steel depends on your priorities: O1 tool steel gives better edge holding, while A2 steel offers better toughness and stability.
Both O1 steel for knives and A2 steel knives are viable, depending on the knife’s purpose.
If you need a simple, affordable, and easy-to-heat-treat steel for knife making or cold tooling, O1 tool steel is an excellent choice.
If you prefer higher toughness, less distortion, and excellent all-around performance, A2 tool steel is your go-to.
Looking for a supplier? We provide O1 tool steel for sale and A2 tool steel for sale, with bulk pricing, OEM service, and fast international delivery. Contact us for O1 and A2 tool steel, cut-to-size service, custom packaging, and global supply.
Email: info@cjmstainlesssteel.com
WhatsApp: +86 181 9190 6640
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