Domestic Valve Materials Frequently-used Technical Standard, Ductile Iron Specification, Mechanical Property
| Grade | Wall Thickness/mm | Tensile Strength σb/MPa |
Yield Strength σ0.2/MPa |
Elongation δ/% |
Reference Value | ||||
| ≥ | HardnessHB | Main Microstructure | |||||||
| QT400-18 | ＞30～60 | 390 | 250 | 18 | 130～180 | Ferrite | |||
| ＞60～200 | 370 | 240 | 12 | ||||||
| QT400-15A | ＞30～60 | 390 | 250 | 15 | 130～180 | Ferrite | |||
| ＞60～200 | 370 | 240 | 12 | ||||||
| QT500-7A | ＞30～60 | 450 | 300 | 7 | 170～240 | Ferrite+Pearlite | |||
| ＞60～200 | 420 | 290 | 5 | ||||||
