ABSTRACT

    Casting simulation requires accurate and reliable material property data, including the fraction solid transformed, specific heat capacity, thermal conductivity and density, all of which as a function of temperature. Such data are usually gathered from experimental sources, which has significant disadvantages in that not all of the required data is available, measurement of high temperature properties is expensive, and furthermore the properties can be sensitive to microstructure as well as to alloy composition. A modelling route that can calculate reliably all the relevant material properties would be of great benefit.

    This paper briefly describes the development of a computer software JMatPro that can provide reliable and cost-effective material data required in casting simulation for multi-component commercial alloys. The property data calculated by JMatPro has been used as direct inputs to casting simulation software MAGMASOFT®. The focus of this paper is to examine how changes in composition within the specification range of an alloy may affect its properties during solidification, and how casting simulation results are consequently influenced.

INTRODUCTION

    Casting process simulation is now widely accepted as an important tool in product design and process development to improve yield and casting quality. Such simulation requires high quality information concerning physical and thermo-physical properties during solidification. Some properties have been measured for specific alloys, but the number of alloys for which information is available is limited. Furthermore, the information may be incomplete in the sense that not all properties have been measured and, sometimes, disparate information from a variety of sources is used to build up the database for one specific alloy. The latter situation can lead to inconsistent results, as the composition of the alloys used for database creation may not be the same and consequently critical temperatures, such as for the solidus and invariant reactions, may differ between the alloys. To overcome the lack of data and provide reliable and cost-effective data for process simulation, as well as achieve a better understanding of how changes in composition within a specification range of an alloy may affect solidification properties, it is highly desirable to develop computer models for calculation of the thermo-physical and physical properties of multi-component alloys during solidification.

``````