Cast Iron
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Property
Cast iron is composed of iron and 2.0 – 4.5% of carbon content. The table below shows some common properties of cast iron. Cast iron piping material is considered grey cast iron, which, has low melting point and good machinability.
General physical and mechanical properties of gray cast iron:
| Typical chemical composition | Fe: Reminder
C: 1.7 – 4.0% S: 0.1 – 0.2% Si: 0.5- 3.0% Mn: 0.5 – 1.0% P: 0.5 – 1.0% |
| Elasticity | The elasticity of cast iron is stable over time and is retained up to relatively high temperatures. It is comparable to that of spring steel.
Cast iron has no permanent deformation i.e. the material cracks if its elastic limit is exceeded (steel would retain a permanent deformation). |
| Resistance to corrosion | Cast iron has an excellent resistance to corrosion over a wide range of operating environments. Initially the surface will slightly rust but then the rusting is practically arrested at the carbon lamellae.
The corrosion resistance of cast iron is much better than that of steel. |
| Acoustical benefit | More effective in reducing plumbing noise than substitute materials |
| Specific gravity | 7.1 kg/m³ |
| Tensile strength | 137.900 – 310.275 MPa |
| Compressive strength | 551.600 – 930.825 MPa |
| Coefficient of heat capacity | 449 J/kgK |
| Other physical properties | Easily machined and cut. Very large castings practicable. |