O2
Data verifiedO2 is an oil-hardening manganese tool steel that hardens deeper and more uniformly than O1 at the same simple heat treatment. It is a long-standing European and Asian shop standard as 1.2842 / 9Mn2V.
Chemical composition
| Element | Content (%) |
|---|---|
| C | 0.85–0.95 |
| Si | 0.10–0.50 |
| Mn | 1.40–1.80 |
| Cr | ≤0.50 |
| V | ≤0.30 |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Delivery condition | Annealed |
| Hardness (hardened) | 57–62 HRC |
| Density | 7.85 g/cm³ |
Heat treatment
Harden 790–820 °C oil; temper 150–250 °C. Deeper hardening than O1 thanks to high manganese.
Equivalent grades
| Standard | Designation |
|---|---|
| din | 1.2842 |
| aisi | O2 |
| jis | SKS31 (near) |
| gb | 9Mn2V |
Compare side by side: O2 vs 1.2842 · O2 vs O1
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Punches, dies, taps, reamers, gauges, bushings, forming rolls.
Processing: Easy machining and forgiving hardening; distortion slightly higher than air-hardening grades, so not for the thinnest intricate dies.
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Ask for a quotationVisit NasteelSource: ASTM A681 / EN ISO 4957 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.