O1
O1 is a designation in AISI / SAE for the material held under material number 1.2510, also listed as 100MnCrW4. It is a material in the category Tool steels for cold work. We list 16 designations recorded for this grade, in the standards DIN / EN, UNS, AISI / SAE, BS, AFNOR, UNE, ISO, JIS, GB, GOST, UNI, SS, ČSN and PN.
If you came for one of these
The most-used names for this grade.About Tool steels for cold work
Cold-work tool steels are high-strength tool materials designed for shaping, cutting and forming operations carried out without significant heating of the workpiece. They are characterised by high hardness, wear resistance and the ability to retain a sharp or precise working edge, making them suitable for dies, punches, cutting tools and other tooling exposed to repeated mechanical contact.
This describes the material class as a whole. Always confirm the individual grade against the standard before ordering.
Also known as
16 designations · 14 standards · nothing hidden- O1This grade’s own name
Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here.
Chemical composition
8 elements on file · weight %What this alloy is
Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade.
| Element | % by weight |
|---|---|
0.9–1.05 | |
0.15–0.35 | |
1–1.2 | |
0.035 | |
0.035 | |
0.5–0.7 | |
0.05–0.15 | |
0.5–0.7 |
The scale is logarithmic, not the element’s raw share of the alloy — the only honest way to fit 0.01 % and 100 % in one picture, and it means every value here can be compared with every other.
| Element | As publishedsource text, verbatim | Min% by weight | Max% by weight | Bound |
|---|---|---|---|---|
| C | 0,90-1,05 | 0.900 | 1.050 | Range |
| Si | 0,15-0,35 | 0.150 | 0.350 | Range |
| P | 0,035 | 0.035 | 0.035 | Exact |
| S | 0,035 | 0.035 | 0.035 | Exact |
| V | 0,05-0,15 | 0.050 | 0.150 | Range |
| Cr | 0,50-0,70 | 0.500 | 0.700 | Range |
| Mn | 1,00-1,20 | 1.000 | 1.200 | Range |
| W | 0,50-0,70 | 0.500 | 0.700 | Range |
The published column is the source string byte-for-byte, decimal comma and all; Min and Max are the parsed bounds. Elements not listed have no value on file — they are omitted, never inferred.
Predicted transformation temperatures
Not enough recorded composition to predict a transformation temperature for this grade — missing: Ni, Mo.
Physical & mechanical properties
An absent property means we hold no value for it — it is left out rather than estimated, interpolated from a neighbouring grade, or filled from a handbook. It does not mean the property is undefined for the material.
Heat treatment
GB /T 1299-2025
- Quenching800–830 °CCooling Oil
Supply condition
- QuenchingTest specimen
- AnnealingSupply condition
Conditions the standard permits on delivery. No temperature or medium is published for these, so no order and no alternation is implied.
Source: www.caishuku.com
Similar grades — and why
Selection rule, stated so you can disagree with it: same number class 1.2, a shared category, and a published range for Mn / Cr that overlaps this grade’s. These are neighbours in composition space — they are not equivalents, and none is claimed to be interchangeable with this grade.
Looking for this grade under another name?
Search the catalogue by designation, material number or composition — every name on this page is itself a way in.