Casting Ductile cast iron
Material Description
Ductile cast iron, also known as nodular cast iron or spheroidal graphite iron, is a versatile and widely used material in casting applications. This type of cast iron derives its name from its unique microstructure, which consists of graphite nodules embedded in a matrix of ferrite and pearlite. This microstructure imparts several remarkable material properties to ductile cast iron, making it a popular choice in various engineering and industrial applications.
One of the most significant attributes of ductile cast iron is its exceptional ductility and toughness. Unlike traditional gray cast iron, ductile cast iron possesses a superior ability to deform plastically before breaking, thanks to the spherical graphite nodules. This means it can withstand considerable stress and strain without failure, making it an ideal material for parts subjected to dynamic loads and shock absorption. Additionally, ductile cast iron exhibits high tensile strength, good wear resistance, and excellent machinability, contributing to its suitability for applications ranging from automotive components and pipes to heavy machinery and construction materials.
The microstructure of ductile cast iron not only provides excellent mechanical properties but also confers corrosion resistance and heat resistance. Furthermore, its good castability and cost-effectiveness make it a preferred choice for a wide range of casting processes. Overall, ductile cast iron’s unique combination of material properties, including ductility, strength, toughness, and resistance to various environmental factors, makes it a versatile and reliable material for various industrial applications where strength and durability are paramount.
Industry Applications
Ductile Cast Iron is employed in aerospace for landing gear, medical devices for radiation therapy machines, and automotive for brake calipers, due to its strength and shock absorption.
Finishing Options
Paint or Spray Coating, Powder Coating, Epoxy Coating
| Density | Tensile Yield Strength (MPa) | Fatigue Strength (MPa) | Hardness (Brinell) | Thermal Conductivity (W/m-K) | Coeff. of Thermal Expansion (mm/mdeg) | Electrical Resistivity (micro Ohm-cm) |
|---|---|---|---|---|---|---|
| 7 | 370-600 | 200-350 | 170-240 | 40-60 | 45210 | 0.56 x 10^-7 |
Design Recommendation
Ductile cast iron, known for its enhanced ductility and tensile strength compared to gray iron, offers more design flexibility. It still requires uniform wall thickness and draft angles for easy part removal. Thicker sections can be incorporated where additional strength is necessary. The unique properties of ductile iron make it an excellent choice for components that need both strength and ductility.
Cost Saving Tip
In ductile iron casting, achieving cost savings involves optimizing gating systems to minimize turbulence and gas entrapment during the pour. Proper riser design can reduce the need for additional feeding materials, saving costs. Recycle scrap and excess ductile iron, and use an energy-efficient induction furnace for melting. Implementing process controls, such as automatic inoculation, can enhance consistency and reduce defects, ultimately saving on rework and scrap.
