Free-cutting bright mild steel — first choice for high-volume machined parts, studs, fittings.
| Property | Typical value |
|---|---|
| Density | 7850 kg/m³ |
| Yield | ~340 MPa |
| Tensile | 400–550 MPa |
| Elongation | ~14 % |
| Young's E | 210 GPa |
| Hardness | ~150 HB |
| CTE | ~12 µm/m·K |
| Thermal cond. | ~50 W/m·K |
| Max service | ~350 °C |
| Poisson ν | ~0.29 |
| Shear modulus G | ~81 GPa (derived) |
| Shear strength | ≈0.6 × UTS (design convention — not test data) |
| Specific heat | ~460–480 J/kg·K |
| Elec. resistivity | ~0.15–0.20 µΩ·m |
| Melting range | ~1450–1520 °C |
| Fatigue (indicative) | — (sulphide inclusions degrade fatigue — avoid for cyclic duty) |
~100% (the reference). Sulphur gives clean chip; ideal for CNC/auto-lathe.
High sulphur → hot-short cracking; welding not recommended. Braze/mechanical fix.
| System | Designation |
|---|---|
| EN | 11SMn30 / 1.0715 (Pb: 11SMnPb30 / 1.0718) |
| DIN | 9SMn28 / 1.0715 |
| AISI | 1213 / 1215 (Pb: 12L14) |
| JIS | SUM22 / SUM23 (Pb: SUM24L) |
| BS | BS 970 230M07 (EN1A) |
| UNS | G12130 / G12150 |
Equivalents & alternatives: 230M07 (EN1A); 1.0715 (11SMn30); AISI 1213/1215. Leaded 230M07Pb (EN1APb) for finer finish. Alt: EN3B where welding needed.
General structural mild steel — sections, plate, weldments. The default for fabrication.
Carbon steelHigher-strength structural steel — same weldability as S275 with ~30% more yield.
Carbon steelGeneral bright mild steel bar — weldable, case-hardenable, good all-rounder for machined parts.
Carbon steelMedium-carbon steel — shafts, studs, gears, keys. Through-hardenable to moderate strength.
