Iron Castings

Gray Iron - Flake graphite provides gray iron with unique properties ( such as excellent machinability ) at hardness levels that produce superior wear – resistant characteristics, the ability to resist galling, and excellent vibration dampening. It is still widely used by all industries and is a low cost solution to many problems.

Ductile Iron - An unusual combination of properties is obtained in ductile iron because the graphite occurs as spheroids rather than as flakes. The different grades are produces by controlling the matrix structure around the graphite. By the use of alloying additions and heat treatment a wide range of strengths and toughness is obtained. With the newest series called Austempered ductile iron (ADI) strengths can match that of cast steel but with a lower modulus.

Compacted Graphite Iron (CGI) - In CGI, graphite locally occurs as interconnected blunt flakes. This graphite structure and the resulting properties are intermediate between gray and ductile irons. The compacted graphite shape also is called quasi-flake, aggregated flake, semi-nodular, and vermicular graphite. Most recently CGI is making headway for engine blocks where the ability to cast thin but strong sections is proving very cost effective.

White Iron - White iron is hard and essentially free of graphite. The metal solidifies with a compound called cementite, which is a phase that dominates the microstructure and properties of white iron. The carbides are in a matrix that may be pearlitic, ferritic, austenitic, martensitic, or any combination thereof. Where extreme wear and corrosion resistance is required this material is a proven winner.

Malleable Iron - In malleable iron, the graphite occurs as irregular shaped nodules called tempered carbon because it is formed in the solid state during heat treatment. The iron is cast as a white iron of suitable chemical composition to respond to the malleabilizing heat treatment. Malleable iron was the forerunner to ductile iron. Its use today is very limited but it can be provided if desired.

Alloyed Iron - This classification includes gray irons, ductile irons, and white irons that have more than 3% alloying elements (nickel, chromium, molybdenum, silicon, or copper). Where ever superior physical properties are needed this type of iron is considered.