The purpose of this part of ISO/TR 10809 is to assist the designer and engineer in understanding the family of cast iron materials and to utilize them with a more complete knowledge of their potential, among the wide range of other engineering materials and fabrication methods now available. A considerable amount of the data provided are metallurgical, but it is usually the metallurgical aspects of the cast irons that create misunderstandings when these materials are specified. This is because metallurgy is not one of the scientific disciplines taught to engineering students. Thus, such students often have a lack of knowledge regarding the fundamentals underpinning the material properties of cast irons. This part of ISO/TR 10809 suggests what can be achieved, what cannot be achieved and why, if and when cast irons are specified. It is not designed to be a textbook of metallurgy. It is intended to help people to choose the correct material for the right reasons and also to help to obviate the specification or expectation of unrealistic additional requirements, which are unlikely to be met and which can be detrimental to the intended application.