Grey Iron Castings
Gray iron is one of the oldest cast ferrous products. In spite of competition from newer materials and their energetic
promotion, gray iron is still used for those applications where its properties have proved it to be the most suitable
material available. Next to wrought steel, gray iron is the most widely used metallic material for engineering purposes.
Production of gray iron castings is about two and one-half times the volume of all other types of castings combined.
There are several reasons for its popularity and widespread use. It has a number of desirable characteristics not
possessed by any other metal and yet is among the cheapest of ferrous materials available to the engineer.
Gray iron is one of the most easily cast of all metals in the foundry. It has the lowest pouring temperature of the
ferrous metals, which is reflected in its high fluidity and its ability to be cast into intricate shapes. As a result
of a peculiarity during final stages of solidification, it has very low and, in some cases, no liquid to solid shrinkage
so that sound castings are readily obtainable. For the majority of applications, gray iron is used in its as-cast condition,
thus simplifying production. Gray iron has excellent machining qualities producing easily disposed of chips and yielding
a surface with excellent wear characteristics. The resistance of gray iron to scoring and galling with proper matrix and
graphite structure is universally recognized. Gray iron castings can be produced by virtually any well-known foundry process.