Ductile Iron Microstructure Simulation

Spheroidal graphite cast iron , As important engineering material ,its production has been increasing in many countries and its production technology has been established . However , there sre still many problems on casting quality because it is difficult for engineers to see and understand what is really happening during casting solidification . In order to more control the quality of the spheroidal graphite cast iron ,in this paper ,according to the practice, the present theory of formation, growing of spheroidal graphite and crystal, and advanced compute technology , Microsructure formation during metal solidification are simulated , which is also called Micro-Modelling . It is ralative to Macro-Modelling during solidification. To be specific , it means the simulation of solidification process at the scale of grain.According to the thermodynamics and solidification theory in this paper , the mathematical and physical model , which coupled heat transfer , solute transfer , nucleation of graphite and austenite , the growth of praphite and austenite was developed . Simulating the grain nucleation and growth of austenite by using Monte Carlo (MC) method . MC method is based on the law of the lowest energy and the effects of bulk free energy and interfacial energy are taken into account here . Accoring to the model which have been developed , the program of 3-dimensional calculation simulation and 2-dimensional image display is developed by using Microsoft Visual C++ 6.0 .Local Area Simulation (LAS) is developed to reduce the amount of calculation of Micro-Modelling by only choosing local area to simulate . TheLAS method includes three parts : mapping the simulation data belonging to Macro-scope onto the local area , dealing with the boundary of the local area and magnifying the graphical results of the local area..Experimental study on the solidification process of the spheroidal graphite cast iron (the chemical composion: C3.7%,Si3.3%, Mn <0.4 % ) in sand is compared to the models of this dissertation . Microsrueture during solidification are simulated by software which was programmed. The results of simulation are compared to the experimental results . It shows that the models used to Micro-Modelling can meet the targets .