Cast iron is a metal with a long history and a wide geographical area of production, both in the UK and abroad. As a result various terms have developed over the years to describe the different forms of cast iron. This can lead to confusion. Ordinary cast iron can be known simply as cast iron or as grey iron or flake graphite iron and ductile iron can be known as SG or spheroidal graphite. The alloyed irons have the same problem.
The wear resistant irons can be called Ni Hard, High Chrome or 28% Chrome whilst the high nickel heat and corrosion resistant irons can also be known as Ni Resist. Austempered ductile iron is often described by its initials ADI and compacted graphite iron can be known in the same way, CGI.