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Open access

B. Mrzygłód and K. Ścira

Module to Generate Rules for the Knowledge Base in a CAPCAST Expert System

The study presented here is related with one of the components of a hybrid decision support system called CAPCAST (Computer Aided Process - CAST), developed under a research project at the Faculty of Metals Engineering and Industrial Computer Science, AGH University of Science and Technology. This is a module for rule generation to serve the knowledge base operating in an expert system. The scope of the system operation involves the selection of technological parameters for the manufacture of machine parts from ductile iron. However, it can be extended to include other materials and technologies.

Open access

I. Olejarczyk-Wożeńska, H. Adrian and B. Mrzygłód

Abstract

The paper presents a mathematical model of the pearlite - austenite transformation. The description of this process uses the diffusion mechanism which takes place between the plates of ferrite and cementite (pearlite) as well as austenite. The process of austenite growth was described by means of a system of differential equations solved with the use of the finite difference method. The developed model was implemented in the environment of Delphi 4. The proprietary program allows for the calculation of the rate and time of the transformation at an assumed temperature as well as to determine the TTT diagram for the assigned temperature range.

Open access

B. Mrzygłód, J. Durak, D. Śmigiel and K. Daczyszyn

Abstract

The article presents two modules operating in a hybrid CAPCAST system implemented in the Department of Applied Computer Science and Modelling, AGH University of Science and Technology, Cracow. These are the modules: CAPCAST-base of producers and CAPCAST-base of materials. Registered producers may benefit from other modules of the system, the base can also be an independent source of knowledge about Polish foundries and their production capacity, and can serve as a kind of platform for the implementation of the basic functions of e-business. The base of materials can also be a source of knowledge about materials, and it allows searching and filtering the lists of materials in terms of user-selected attributes using a multi-level search engine. This module is integrated with the rest of the system and can be used by other modules. The system has been developed at the AGH Department of Applied Computer Science and Modelling in Cracow.

Open access

B. Mrzygłód, A. Kowalski, I. Olejarczyk-Wożenska, T. Giętka and M. Głowacki

Abstract

The results of examinations of microstructure and an analysis of its impact on selected mechanical properties of austempered ductile iron (ADI) were presented in the paper. The ADI was produced from the ductile iron containing 1.56% Ni only alloying addition. The effect of the austempering time and temperature on the microstructure and mechanical properties of the examined cast iron was considered. Constant conditions of austenitizing were assumed and six variants of the austempering treatment were adopted. The studyof mechanical properties included a static tensile test, Charpy impact strength test and Brinellhardness measurement.

This work complements the knowledge about alloying additions effect on microstructure and mechanical properties of ADI and focuses on the impact of a single alloying element (Ni).

Open access

B. Mrzygłód, P. Matusiewicz, A. Tchórz and I. Olejarczyk-Wożeńska

Abstract

Stereological description of dispersed microstructure is not an easy task and remains the subject of continuous research. In its practical aspect, a correct stereological description of this type of structure is essential for the analysis of processes of coagulation and spheroidisation, or for studies of relationships between structure and properties. One of the most frequently used methods for an estimation of the density Nv and size distribution of particles is the Scheil - Schwartz - Saltykov method. In this article, the authors present selected methods for quantitative assessment of ductile iron microstructure, i.e. the Scheil - Schwartz - Saltykov method, which allows a quantitative description of three-dimensional sets of solids using measurements and counts performed on two-dimensional cross-sections of these sets (microsections) and quantitative description of three-dimensional sets of solids by X-ray computed microtomography, which is an interesting alternative for structural studies compared to traditional methods of microstructure imaging since, as a result, the analysis provides a three-dimensional imaging of microstructures examined.

Open access

I. Olejarczyk-Wożeńska, A. Adrian, H. Adrian and B. Mrzygłód

Parametric Representation of TTT Diagrams of ADI Cast Iron

The method of parametric representation of TTT diagrams on example of selected austempered ductile cast irons is presented. TTT diagrams were digitalised and n, k parameters of Johnson Mehl equation were calculated. The relationships between n, k parameters and transformation temperature were analysed for two ADI irons. Knowledge of these parameters enables to calculate the progress of austenite to bainite transformation.

Open access

B. Mrzygłód, A. Kowalski, I. Olejarczyk-Wożenska, H. Adrian, M. Głowacki and A. Opaliński

Abstract

Metallographic examinations and mechanical tests were carried out on the ductile iron with additions of Ni, Cu and Mo in as-cast state and after austempering. TTT and CCT diagrams were plotted. The heat treatment was performed in six different variants. Studies included qualitative assessment of the microstructure and testing of mechanical properties such as R0,2, Rm, A, Z, HRC, KC. An analysis of the obtained results was also presented.

Open access

I. Olejarczyk-Wożeńska, H. Adrian, B. Mrzygłód and M. Głowacki

Abstract

A mathematical model of austenite - bainite transformation in austempered ductile cast iron has been presented. The model is based on a model developed by Bhadeshia [1, 2] for modelling the bainitic transformation in high-silicon steels with inhibited carbide precipitation. A computer program has been developed that calculates the incubation time, the transformation time at a preset temperature, the TTT diagram and carbon content in unreacted austenite as a function of temperature. Additionally, the program has been provided with a module calculating the free energy of austenite and ferrite as well as the maximum driving force of transformation. Model validation was based on the experimental research and literature data. Experimental studies included the determination of austenite grain size, plotting the TTT diagram and analysis of the effect of heat treatment parameters on the microstructure of ductile iron. The obtained results show a relatively good compatibility between the theoretical calculations and experimental studies. Using the developed program it was possible to examine the effect of austenite grain size on the rate of transformation.

Open access

K. Regulski, D. Wilk-Kołodziejczyk, B. Kacprzyk, G. Gumienny, G. Rojek and B. Mrzygłód

Abstract

This article presents the methodology for exploratory analysis of data from microstructural studies of compacted graphite iron to gain knowledge about the factors favouring the formation of ausferrite. The studies led to the development of rules to evaluate the content of ausferrite based on the chemical composition. Data mining methods have been used to generate regression models such as boosted trees, random forest, and piecewise regression models. The development of a stepwise regression modelling process on the iteratively limited sets enabled, on the one hand, the improvement of forecasting precision and, on the other, acquisition of deeper knowledge about the ausferrite formation. Repeated examination of the significance of the effect of various factors in different regression models has allowed identification of the most important variables influencing the ausferrite content in different ranges of the parameters variability.