Sead Spuzic

Wear of hot rolling mill rolls: an overview

Abstract Rolling is today one of the most important industrial processes because a greater volume of material is worked by rolling than by any other technique. Roll wear is a multiplex process where mechanical and thermal fatigue combines with impact, abrasion, adhesion and corrosion, which all depend on system interactions rather than material characteristics only. The situation is more complicated in section rolling because of the intricacy of roll geometry. Wear variables and modes are reviewed along with published methods and models used in the study and testing of roll wear. This paper reviews key aspects of roll wear control — roll material properties, roll pass design, and system factors such as temperature, loads and sliding velocity. An overview of roll materials is given including adamites, high Cr materials, high speed tool steels and compound rolls. Non-uniform wear, recognised as the most detrimental phenomenon in section rolling, can be controlled by roll pass design. This can be achieved by computer-aided graphical and statistical analyses of various pass series. Preliminary results obtained from pilot tests conducted using a two-disc hot wear rig and a scratch tester are discussed.

A Knowledge Based Hybrid Model for Improving Manufacturing System in Rolling Mills

Hot steel rolling is amongst the most important industrial techniques because of huge amount of consumed resources, immense environmental impact, and the significance and enormous quantity of long products. Criteria for improving rolling operations include process efficiency, resource consumption, system reliability, product quality and ergo-ecological sustainability. There is an increasing availability of information within and beyond the domain of forming by rolling. With advances in computerised information processing, it becomes apparent that further progress is to be sought in intelligently combining the strategies and theories developed in differing disciplines. The key to optimising rolling systems is to be found in hybrid models. This approach calls for utilising cross-disciplinary knowledge, including a selection amongst methods such as stochastic, fuzzy and genetic modelling, process control and optimisation as well as supply chain and maintenance management. Evidence obtained by experiments using small-scale chemo-physical modelling encourages the use laboratory rolling for preliminary validations. Research strategy is conceptualised on the basis of a knowledge-based hybrid model. The sample space for this model is constituted by the rolling passes translated into the form of vectors. An example of a rolling pass translation into the vector form is presented.

Development of parameterized roll pass design based on a hybrid model

Hot steel rolling is an important manufacturing process used to efficiently provide a wide range of products of high quantity and quality. In order to meet the continuously increasing demands, both an improved quality and a broader variety of products must be delivered along with improvements in efficiency, reliability and sustainability of rolling mill systems. Further development of roll pass design presents one of the central aspects in these efforts. However, to optimize roll pass design, numerous combinations of system parameters must be analyzed and correlated. This cannot be done through a single deterministic model. Therefore, a parameterized hybrid model based on combining cross-disciplinary knowledge is proposed to improve the quality and efficiency of roll pass design. Application of artificial intelligent algorithms is envisaged for the roll pass design optimization and a methodology for constructing the relevant hybrid model is described.

Investigation of Roll Pass Optimal Design Based on IGA

The primary purpose of this study is to develop a genetic algorithm based computer-aided roll pass optimal design (CAROD) system to support the generalized roll pass design for rod rolling, where the final products are round bars with different sizes. The system was developed to minimize the number of roll passes, decrease the trails and errors in industry, as well as extend the work range of multi-pass rolling systems for rod rolling. Parametric equations were established for geometrical modeling and graphic plotting, which can realize to the parametric transformation for roll pass design and optimization. A methodology based on a hybrid model was proposed to choose passes with different profiles for the multi-pass rod rolling system. In addition, an improved genetic algorithm (IGA) was employed for the optimization of roll passes. A MATLAB program was designed to achieve all these objectives. To reduce the complexity and computational burden of the software, some reliable empirical formulas were applied in this system. Finally, the proposed approach has been applied in a rod rolling system; through simulation and comparison of results against analytical solutions, numerical analysis and experimental data presented by other researchers, it was found that this system is reliable, effective and easier to use.

Defining Knowledge Constituents and Contents

While it appears that a consensus is crystalising with regard to the hierarchy of concepts such as “knowledge”, “definition” and “information”, there is an increasing urgency for improving definitions of these terms. Strategies such as “knowledge extraction” or “data mining” rely on the increasing availability of digital (electronic) records addressing almost any aspect of socio-economic realm. Information processors are invaluable in the capacity of turning large amount of data into information. However, a new problem emerged on the surface in this new information environment: numerous concepts and terms are blurred by ambiguous definitions (including the concept of ‘definition’ itself). This triggered a need for mitigating hindrances such as homonymy and synonymy, leading further to demands on the decoding software complexity of which equals the artificial intelligence applications. Information technology presumably copes with this diversity by providing the information decoding ‘tools’. This opens a never-ending opportunity for further permutations of tasks and service abilities. The solution, however, is to address the causes rather than indulge in multiplying the superficial remedies. Clearly, the multiplicity of definitions for the same concepts, false synonyms and so forth show that there is a need for introducing definitions of sufficient dimensionality. In this article, a number of examples of important concepts are presented first to point at the ambiguities associated with them, and then to propose their disambiguation. The minimum intent is to demonstrate how these key terms can be defined to avoid ambiguities such as pleonasm, homonymy, synonymy and circularity. KEywoRDS Ambiguity, Concept, Knowledge