The word ‘ductility’ means a sold material’s ability to change under tensile stress. Tensile stress is the pulling force applied by a similar solid object on another object. Malleability of metal is a similar term used to describe a materials ability to change under ‘compressive’ stress, for instance, the reshaping of metal into sheets by use of a hammer or roller for example. The term ‘ductile iron’ means that the material has the ability to deform under stress without fracture, which means no splitting or damage, occurs on the material
Ductile iron can also be known as:
- Ductile cast iron
- Nodular cast iron
- Spheriodal graphite iron
- Spherulitic graphite cast iron
- SG iron
Ductile iron is not a single material but is part of a group of materials which can be produced to have a wide range of properties through control of the microstructure. The shape of the graphite defines its group as they are in nodule form rather than flake form. Due to this particular form, the material does not allow cracking and this is why the material is considered ductile when put under pressure.