Cast iron is an alloy of iron that contains traces of carbon, silicon, and manganese as its major elements.With its relatively low melting point, resistance to wearability and deformity along with great castability and machining capability, Cast Iron (CI) have wide range of application in automotive, power plant, railways and steel industry
Range of compositions for typical unalloyed cast irons
Values in percent (%)
| Type of Iron | Carbon | Silicon | Manganese | Sulfur | Phosphorus |
|---|---|---|---|---|---|
| Gray | 2.5 - 4.0 | 1.0 - 3.0 | 0.2 - 1.0 | 0.02 - 0.25 | 0.02 - 1.0 |
| Ductile | 3.0 - 4.0 | 1.8 - 2.8 | 0.1 - 1.0 | 0.01 - 0.03 | 0.01 - 0.1 |
| Compacted Graphite | 2.5 - 4.0 | 1.0 - 3.0 | 0.2 - 1.0 | 0.01 - 0.03 | 0.01 - 0.1 |
| Malleable (Cast White) | 2.0 - 2.9 | 0.9 - 1.9 | 0.15 - 1.2 | 0.02 - 0.2 | 0.02 - 0.2 |
| White | 1.8 - 3.6 | 0.5 - 1.9 | 0.25 - 0.8 | 0.06 - 0.2 | 0.06 - 0.2 |
A few common mechanical properties for cast iron include:
This table summarizes some of the key mechanical properties for various grades of cast iron.
| Brinell Hardness | Tensile Strength | Modulus of Elasticity | % Elongation (in 50 mm) | |
|---|---|---|---|---|
| Gray iron class 25 | 187 | 29.9 ksi | 16.6 Msi | - |
| Gray iron class 40 | 235 | 41.9 ksi | 18.2 Msi | - |
| Ductile iron grade 60-40-18 | 130-170 | 60 ksi | 24.5 Msi | - |
| Ductile iron grade 120-90-02 | 240-300 | 120 ksi | 25.5 Msi | - |
| CGI grade 250 | 179 max | 36.2 ksi min | 3 | |
| CGI grade 450 | 207-269 | 65.2 ksi min | 1 |