Advances in the development of high nodule count spheroidal graphite cast iron

P. DAVID; J. MASSONE; R. BOERI; J. SIKORA

São Paulo– SP – Brazil

Conferencia; 12st CONAF – Conference on Casting; 2005

This work focuses on the development of a horizontal and a vertical mould designed to produce thin ductile iron plates of 1.5 to 4 mm thickness and the study of the mechanical properties and microstructure. The horizontal mould was designed based on empirical rules, while the vertical mould was based on numerical simulations of fluid flow and thermal field, carried out by using the software NovaFlow&Solid®. All tests were carried out on ferritised samples. Melts of carbon equivalent values ranging from 4.06 to 4.85 were used to cast plates of thickness ranging from 1.5 to 4mm. The results show that the adoption of empirical rules and a non-pressurised configuration were not enough to guarantee proper filling. An optimised design was obtained through the use of mathematical modeling On the other hand, irons having carbon equivalent values greater than 4.6 exhibit a marked tendency to develop exploded graphite and agglomeration of graphite nodules. As a result, these irons show scattered values of mechanical properties. As irons are produced with carbon equivalent values below 4.6%, the mechanical properties improve, reaching levels that satisfy the requirements of standards ASTM A536