Solidification, processing and properties of ductile cast iron

Abstract

Ductile cast iron has been an important engineering material in the past 50 years. In that time, it has evolved from a complicated material that required the foundry metallurgist's highest skill and strict process control to being a commonly used material that can easily be produced with modern process technology. Yet, for the skilled metallurgist and foundry engineer, it is a material that can be engineered to meet extreme demands with regard to mechanical properties and geometrical complexity. It is therefore a material that has been in growing use since its discovery. And the results of the latest years of research indicate that ductile cast iron in the future will become a highly engineered material in which strict control of a range of alloy elements combined with intelligent design and highly advanced processing allows us to target properties to specific applications to a much higher degree than we have seen previously. It is the aim of the present paper to present ductile iron as a modern engineering material and present the many different possibilities that the material hides. Focus will be on the latest research in solidification and melt treatment. But for completeness and to illustrate how ductile iron's properties are optimised, the essentials of heat treatment are described too. It is the hope that researchers will find a comprehensive treatment of ductile cast iron metallurgy and that engineers and designers will be presented with the latest information on, and references to, the properties and possibilities in ductile cast iron.

A micro-mechanical analysis of thermo-elastic properties and local residual stresses in ductile iron based on a new anisotropic model for the graphite nodules

“…An important observation is to be made regarding the experimental values to be compared with those delivered by equation (4). As shown by Sjögren and Svensson [6], the graphite morphology strongly affects the macroscopic Young's modulus of SGI, meaning that a correction for the non-perfect spherical nodule shape of the material under investigation is necessary.…”

“…Its high technological importance is confirmed by recent market growth analyses [3], indicating that as many as 25 % of the castings currently produced worldwide are made of ductile iron. Typical applications include small and medium sized heavily loaded parts with high demands for consistent quality for the automotive sector and very large industrial components with extreme demands for mechanical properties, particularly fatigue strength and fracture toughness [4].…”

Comportamiento frente a la corrosión de fundiciones con grafito laminar y esferoidal parcialmente modificadas con silicio en NaCl 0,03 M

“…Las fundiciones base hierro son, sin lugar a dudas, uno de los materiales más empleados debido principalmente a sus altas prestaciones mecáni-cas y bajo coste (Tiedje, 2010). Por esta razón, la mayor parte de los sistemas de conducción y distribución de aguas se han venido haciendo en fundiciones de hierro desde hace más de 500 años.…”

Materials for Tribology

“…The material is then kept at this temperature for a time suitable to stabilize austenite, and then it is cooled down to room temperature. An ausferritic (AF) microstructure is obtained, characterized by the presence of bainitic ferrite plus carbon stabilized austenite, that increase strength and ductility [13]. As an example, Fig.…”