1.0721 (10S20) vs Y12
These two grades are listed as equivalents of each other: their chemistry windows overlap and they serve the same applications. They are not always identical — check the differences below before substituting, especially in certified designs.
1.0721 (10S20)
Carbon Steel
10S20 (1.0721) is a case-hardening free-cutting steel under EN 10087: moderate sulfur (0.15–0.25%) balances machinability against the ability to carburize small parts that need a wear-resistant case — a combination plain free-cutting grades cannot offer.
Standards: DIN 1.0721 (10S20)
Y12
Carbon Steel
Y12 is China’s standard sulfur-phosphorus free-cutting steel (GB/T 8731), the domestic equivalent of the 1215 concept. It is produced in large volumes for automatic-lathe parts across Chinese machining shops.
Standards: AISI 1215 (near) · JIS SUM family (near) · GB Y12 (GB/T 8731)
Chemical composition compared (%)
| Element | 1.0721 (10S20) | Y12 |
|---|---|---|
| C | 0.07–0.13 | 0.08–0.16 |
| Si | ≤0.40 | ≤0.15 |
| Mn | 0.70–1.10 | 0.70–1.00 |
| P | ≤0.06 | 0.08–0.15 |
| S | 0.15–0.25 | 0.23–0.33 |
Properties compared
| Property | 1.0721 (10S20) | Y12 |
|---|---|---|
| Case hardness (carburized) | 55–62 HRC (typ.) | — |
| Tensile strength | 360–480 MPa (delivery-condition dependent) | 380–460 MPa (hot rolled, typ.) |
| Density | 7.85 g/cm³ | 7.85 g/cm³ |
Sourcing either grade?
Nasteel stocks both families from Shenzhen with EN 10204 3.1 mill certificates by heat number.
Ask for a quotationSee full data sheets: 1.0721 (10S20) · Y12. Substitution decisions for certified parts stay with the design authority.