Original scientific paper

https://doi.org/10.31803/tg-20180516131304

Cast iron rolls – an overview on the proper hardness assured by the manufacturing process

Imre Kiss orcid.org/0000-0001-5373-7485 ; University Politehnica Timisoara, Faculty of Engineering Hunedoara, Department of Engineering and Management, 5, Revolutiei, 331128 Hunedoara, Romania

Abstract

The manufacturing process of the rolling rolls, as well as the quality of materials used in casting them, can have an important influence upon the quality and the safety of the exploitation. Our approaches to the issue of quality assurance of the rolling rolls, from the viewpoint of the quality of materials that are featured, can cause duration and safety in the rolling exploitation. This research is required because of the numerous flaws that cause rejection, since the phase of melting of these irons is intended to cast rolls. According to the industrial analysis in the cast iron rolls foundries, the results show that one of the main rejection categories is due to the inadequate hardness of the rolls. One of the parameters that will determine the cast iron’s structure is the chemical composition, and this factor could assure the exploitation properties of each roll in all the stands of rolling mill. In this sense, the paper presents an overview of industrial and laboratory research regarding the assurance of the chemical composition of the irons (with nodular graphite) destined for the half–hard rolls casting, and tries to draw some remarks upon the proper correlations of these irons. This study analyses iron rolls cast in combined moulds (iron chill, for the barrel and moulding sand, for the necks of rolls) and includes charges of rolls from half–hard classes, with definite structure and nodular graphite, obtained in simplex cast processes. It presents, in graphical form, the influence of the chemical composition of these irons on the hardness, measured on the barrel. The proper solution is determined through some mathematical restrictions to the input data that the mathematical modelling is initiated with. It will be determined through regression equations, which describe the mathematical dependency between the hardness and the elements of chemical composition – the basic elements (Carbon [C], Manganese [Mn] and Silicon [Si]), the particulate elements (Sulphur [S], Phosphorus [P] and Magnesium [Mg]) and the main alloying elements (Nickel [Ni], Molybdenum [Mo] and Chrome [Cr]). The main results and the graphical addenda are presented.

Keywords

cast iron rolls; chemical composition; hardness; half-hard class; regression surfaces; modelling

Hrčak ID:

221158

URI

https://hrcak.srce.hr/221158

Publication date:

17.6.2019.

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