Ductile (spheroidal graphite) cast iron
Cast iron that, thanks to its spheroidal graphite, is far more ductile and impact-resistant than lamellar graphite cast iron. Widely used for butterfly valve, gate valve and strainer bodies in water and wastewater lines.
- Rp0.2 · MPa
- ≥ 250
- Rm · MPa
- ≥ 400
- TEMPERATURE
- −10 … +350 °C
- COST
Chemical composition
EN 1563 does not specify a chemical composition; the grade is defined by mechanical properties and the foundry sets the composition.
Mechanical properties
| STANDARD · CONDITION | Rp0.2 MPa | Rp1.0 MPa | Rm MPa | A % | KV J |
|---|---|---|---|---|---|
| EN 1563 · t ≤ 30 mm | 250 | — | ≥ 400 | 15 | — |
| EN 1563 · 30 < t ≤ 60 mm | 250 | — | ≥ 390 | 14 | — |
| EN 1563 · 60 < t ≤ 200 mm | 240 | — | ≥ 370 | 11 | — |
Separately cast sample, minimum values for the relevant wall thickness. Hardness for information ≈ 135–180 HB.
Service temperature
EN 1092-2: −10 … 350 °C. For PN16: 16 bar up to 120 °C, 12.8 bar at 300 °C, 11.2 bar at 350 °C. For low temperatures, choose impact-guaranteed EN-GJS-400-18-LT.
This is the limit of the material itself. A valve's service temperature is usually set by the seal and seat materials; product pages give it for each seal option.
Media suitability GENERAL TREND
Emsal assessment. The final choice is made from corrosion tables, taking concentration, temperature, chloride content and flow velocity into account.
Strengths and weaknesses
Strengths
- Higher ductility and impact resistance than lamellar graphite cast iron
- Good castability, complex bodies
- Vibration damping
- More economical than cast steel
Weaknesses
- Requires epoxy coating for corrosion protection
- Difficult to repair by welding
- Mechanical values drop in thick sections
Manufacturing and use
- ECONOMY
- Low. A clear cost advantage over cast steel in water lines.
- MANUFACTURING METHODS
- Sand casting · Epoxy powder coating
- TYPICAL VALVE PARTS
- Body · Cover · Disc (butterfly)
Surface protection
- Wet paintIndustrial wet paint systemEmsal standard · traffic blue
- Epoxy powder coatingElectrostatic epoxy powder coating (oven-cured, FBE)Water lines, internal and external ≥ 250 µm
Used in 3 Emsal products
- 131Knife gate valveBody
- 250Full lift flanged safety valveBody
- 311Rubber expansion jointFlange
Source: EN 1563. Values compiled and verified by Emsal Vana; for binding values, refer to the current edition of the standard and the material certificate.