The various properties of different types of cast iron results in each type being suited for specific applications.
One of the key characteristics of Gray iron is its ability to resist wear even when lubrication supply is limited (e.g., the upper cylinder walls in engine blocks). Gray iron is used to make engine blocks and cylinder heads, manifolds, gas burners, gear blanks, enclosures, and housings.
The chilling process used to make white iron results in a brittle material that is very resistant to wear and abrasions. For this reason, it is used to make mill linings, shot-blasting nozzles, railroad brake shoes, slurry pump housings, rolling mill rolls, and crushers.
Ni-Hard Iron is specifically used for mixer paddles, augers and dies, liner plates for ball mills, coal chutes, and wire guides for drawing wires.
Ductile iron itself can be broken down into different grades, each with their own property specifications and most suitable applications. It is easy to machine, has good fatigue and yield strength, while being wear resistant. Its most well-known feature, however, is ductility. Ductile iron can be used to make steering knuckles, plow shares, crankshafts, heavy duty gears, automotive and truck suspension components, hydraulic components, and automobile door hinges.
Different grades of malleable iron correspond to different microcrystalline structures. Specific attributes that make malleable iron attractive are its ability to retain and store lubricants, the non-abrasive wear particles, and the porous surface which traps other abrasive debris. Malleable iron is used for heavy duty bearing surfaces, chains, sprockets, connecting rods, drive train and axle components, railroad rolling stock, and farm and construction machinery.
Compacted graphite iron is beginning to make its presence known in commercial applications. The combination of the properties of Gray iron and white iron create a high strength and high thermal conductivity product—suitable for diesel engine blocks and frames, cylinder liners, brake discs for trains, exhaust manifolds, and gear plates in high pressure pumps.
The hardness properties of cast iron demand careful selection of machine tool materials. Coated carbides are effective in production machining environments, but newer materials are being developed continuously as technology improves.
Surface finishing of cast iron products varies greatly according to the use.
Electroplating
Hot-dipping
Thermal spraying
Diffusion coating
Conversion coating
Porcelain enamelling
Liquid organic coating
Dry powder organic coating