General
Heat treatment of cast iron

Cast irons consist of a matrix (similar to steel, but with variable carbon content) in which graphite or carbide particles are always present, sometimes in significant proportions (up to around 50% by volume), and mostly originating from stable or metastable eutectics derived from iron-carbon systems [M 380][1][2][3].

The matrix, which can be ferritic, pearlitic, austenitic, martensitic, bainitic, etc., can be modified by heat treatment, depending on its chemical composition, according to the same principles as a steel: quenching, tempering, annealing, etc. ; however, it should be noted that graphite or carbides play an important role in the transformation of the cast iron matrix: