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Influence of Structural Parameters - the Shape of Graphite and Matrix on Change of Ultrasonic Wave Propagation Rate and Value of Attenuation in Graphitic Cast Irons

Belan Juraj, Tillová Eva, Uhríčik Milan, Pastierovičová Lucia

Production Engineering Archives

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2023

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Vol. 29, Iss. 1

23--27

EN

Despite the tendency of the current industry, especially the automotive industry, it is to use modern, light and super-strong materials based on Al or HSLA steels, the application of classic materials such as cast iron still makes sense, especially concerning price and excellent castability. The article presents one of the possible ways of using the ultrasonic non-destructive method in quality control and simpli-fication of the identification of the type of cast iron concerning the change of parameters of ultrasound propagation in materials. The main criteria for assessing the quality and determining the type of graphite cast iron were considered to be the rate of propagation of ultrasound - cL and the value of attenuation , which vary depending on the shape of the graphite and matrix. Graphitic cast irons with different graphite shapes (lamellar, vermicular, and globular shapes) and a matrix with different ferrite/perlite ratios were used as experimental material. Along with the ultrasonic tests, a metallographic analysis was also performed to quantify the microstructure of cast irons.

2

Prediction of Microstructure of Grey Cast Irons by Electrical Resistivity Measurements

Petrič M., Mrvar P., Kastelic S.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 1

365--369

EN

The paper describes the influence of graphite shape, size and amount to electrical properties of different cast irons. Experiments of electrical resistivity measurements were conducted during solidification of four different melts in different time intervals from melt treatment by inoculation and nodularization. Metallographic analyses were made in order to determine the shape, size, distribution and amount of graphite and correlate results with electrical resistivity measurements. It was found out that nodular graphite is giving the lowest electrical resistivity and is decreased during solidification. Electrical resistivity of lamellar cast iron is increased during solidification since lamellas interrupt metal matrix severely. There is no significant difference in resistivity of vermicular cast iron from nodular cast iron. Smaller size of graphite and lower amount of graphite and higher amount of metal matrix also decrease resistivity.

3

Analysis of the Graphite Shape in Cast Iron Obtaining by Inmold Process

Gumienny G., Kurowska B.

Archives of Foundry Engineering

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2015

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Vol. 15, iss. 3 spec.

15--20

EN

The paper presents results of research on the effect of magnesium on the graphite shape in cast iron obtained by Inmold process. For testing Lamet® 5504 master alloy was used. The crystallization process of cast iron with various Mg concentrations was evaluated with use of the thermal and derivative analysis (TDA) method. The conditions were demonstrated for which a flake, vermicular and nodular graphite were obtained. Values of graphite “c” coefficient were analyzed. Results from it the significant differences between the assessment of the graphite on metallographic specimen and by the "c" coefficient. An effect of wall thickness of the casting on the graphite coefficient was indicated.

4

Identification of cast iron type with using of NDT methods

Belan J.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 1 spec.

103--106

EN

The aim of this paper is to demonstrate the capability of ultrasonic techniques in the assessment of the structure and properties of cast irons, and also contribute to the database concerning the use of ultrasonic velocity and attenuation measurements for quality control. In the experiments, cast iron specimens with different graphite shape (lamellar, vermicular and nodular shape) and different matrix composition were cast. Ultrasonic velocity measurements were carried out on the as-cast specimens with STARMANS DiO 562–2CH ultrasonic flaw detector. Then, the results of ultrasonic measurements were correlated with the microstructural investigations on the specimens.