Identification of parameters of the manufacture and operation of heavy castings in function of the casting configuration and cast iron grade

摘要

The specific character of heavy (above 1 tonne) iron castings operation at elevated temperatures does not allow full identification of all functional parameters that occur during this operation. It therefore seems advisable to use numerical calculations in the description and parametrisation of the occurring phenomena. The study presents non-standard methods for testing the surface temperature field isotherms to determine local overheating closely related with the technological procedures, chemical composition and shape geometry under the preset operating conditions. Identification of these parameters can be interpolated to the laboratory conditions and also serve the validation of virtual models subjected to computer simulation. The use of genetic algorithms in the simulation in conjunction with the results of measurements under real conditions allows more accurate determination of the performance characteristics, including, among others, the critical state of stress in the structure. Today, many cast structures are characterised by a sophisticated shape with high degree of the wall thickness variations, designed to have a minimum weight but at the same time creating a lot of problems in their practical manufacture. The, feasible nowadays, concept of ICME - integrated computational materials engineering enables full analysis of the process: from the material development and selection up to the design optimising, allowing for the entire cycle of creation and performance. The study presents parameters describing the boundary conditions and the dynamics of temperature and stress changes in function of the cast iron composition and casting configuration during cooling in a foundry mould and later operation. The actions discussed contribute to the casting weight reduction and performance life prolongation.