Y30 vs Y20
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.
Y30
Carbon Steel
Y30 is the 0.30% carbon member of the GB/T 8731 free-cutting family: sulfur (0.15–0.25%) keeps it fast on the lathe while the medium-carbon base allows real heat treatment, bridging free-cutting bar and plain machinery steel.
Standards: GB Y30 (GB/T 8731)
Y20
Carbon Steel
Y20 moves China’s free-cutting family (GB/T 8731) to a 0.20% carbon base with sulfur-only chip-breaking (no phosphorus boost), trading a little machinability against the Y12/Y15 grades for clearly higher strength.
Standards: GB Y20 (GB/T 8731)
Chemical composition compared (%)
| Element | Y30 | Y20 |
|---|---|---|
| C | 0.27–0.34 | 0.17–0.23 |
| Si | 0.15–0.35 | 0.15–0.35 |
| Mn | 0.70–1.00 | 0.70–1.00 |
| P | ≤0.06 | ≤0.06 |
| S | 0.15–0.25 | 0.15–0.25 |
Properties compared
| Property | Y30 | Y20 |
|---|---|---|
| Tensile strength | 490–610 MPa (hot rolled, typ.) | 430–560 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: Y30 · Y20. Substitution decisions for certified parts stay with the design authority.