Properties of Spheroidal Graphite Cast Iron (SGCI)
Spheroidal graphite cast iron (SGCI) is a type of cast iron that has spherical graphite particles rather than the flake-shaped particles found in gray iron.
This unique microstructure gives SGCI several advantages over gray iron, including:
- Increased strength and ductility: The spherical shape of the graphite particles in SGCI provides a more homogenous distribution of stress and allows for greater deformation before failure.
- Improved machinability: The spherical shape of the graphite particles in SGCI reduces the amount of friction between the cutting tool and the workpiece, making it easier to machine.
- Reduced susceptibility to cracking: The spherical shape of the graphite particles in SGCI helps to distribute stress more evenly, making it less prone to cracking.
- Better wear resistance: SGCI has a higher hardness than gray iron, making it more resistant to wear and abrasion.
- Higher thermal conductivity and better heat dissipation: SGCI has higher thermal conductivity than gray iron, which allows for better heat dissipation and can reduce distortion and cracking during high-temperature applications.
- Good vibration damping: The spherical graphite particles in SGCI act as tiny shock absorbers, providing good vibration damping properties. This makes it ideal for use in parts that are subject to high levels of vibration, such as engine blocks and gearboxes.
- Reduced shrinkage and distortion: The spherical shape of the graphite particles in SGCI helps to reduce the amount of shrinkage and distortion that occurs during the casting process, resulting in more precise and accurate parts.
- Better corrosion resistance: SGCI has better corrosion resistance than gray iron, which makes it suitable for use in parts that are exposed to corrosive environments.
- Reduced porosity: The spherical shape of the graphite particles in SGCI helps to reduce the amount of porosity in the cast iron, resulting in a more dense and stronger material.
- High fatigue strength: SGCI has high fatigue strength and resists fatigue loading better than gray iron.
SGCI is used in a wide range of applications including engine blocks and cylinder liners, gears, pumps, valves, and power transmission equipment, as well as in the construction, mining and oil and gas industries.
It is also important to note that SGCI is a brittle material and must be used with care to avoid cracking.