What is SiMo (Silicon Molybdenum)?
The properties of S.G Iron can be modified to give superior heat resistance characteristics by adding up to 5% Silicon and 1.5% Molybdenum. The material is used in turbo housings, manifolds and other cast turbo chrager parts which require high ductility, oxidation resistance, heat resistance, impact resistance and dimensional stability.
The Microstructure of Silicon Molybdenum
| C=3.2-3.8%, Si=4.0-5.0%, S < 0.02%, Mg=0.03-0.07%, Mo=0.5-1.5% | ||||
Temperature °C | Tensile Strength N/mm² | 0.2% Proof Stress N/mm² | Modulus of Elasticity N/m x 10⁴ | Hardness BHN |
| 23 | 550 | 480 | 14.8 | (200-400) |
| 300 | 480 | 395 | 14 | |
| 500 | 350 | 270 | 12 | |
| 800 | 50 | 30 | 2.5 | |
| Guideline Figures for Maximum Manifold and Exhaust Gas Temperatures | ||
| Material Grade | Max. Manifold Temperature °C | Max. Exhaust Gas Temperature °C |
| EN-GJS-400-15 | 700 | 770 |
| EN-GJS-SiMo (0.5% Mo) | 750 | 820 |
| EN-GJS-SiMo (1.0% Mo) | 780 | 820 |
| EN-GJS-SiMoNi | 795 | 835 |