Steel and Refractory Chemical Interactions and Mechanical Behavior of Plates for Sliding Gate during Steel Continuous Casting

The main objective to increase CC productivity as well as steel quality by using optimized refractory from ladle-tundish-to-mold lead to techniques that allow the prediction of steel and refractory chemical interactions as well as mechanical behavior of refractory component. Specific models (CFD) have also been developed to better take into account the physical parameters at the steel/refractory interface and to optimize steel flow control. They are completed by dedicated thermal stress analysis in order to improve thermal shock resistance. The mechanical Finite Element Analysis evaluations take into account specific mechanical behavior of refractory components as well as high temperature evolution of their properties

Optimisation of Refractory Components of Sliding Gate Mechanism for Continuous Casting

New design techniques have been developed to optimize refractory components of sliding gate mechanism for continuous casting of steel. The overall objective is to increase CC productivity as well as steel quality by using optimized refractory from ladle to tundish. These techniques allow the prediction of steel and refractory chemical interactions and, thus, steel chemistry evolution as well as build up and corrosion occurrence. The recent developments resulted in optimized refractories for sliding gate plates that meet the various continuous casting conditions. Furthermore, fracture mechanical measurements were established as a useful tool in the selection and development of slide gate refractories. The mechanical FEA evaluations take into account specific mechanical behavior of refractory components as well as high temperature evolution of their properties

Steel Flow Control of Continuous Casted Slabs Using Submerged Entry Nozzle Exchange System for Tundish

In the steel making process, the continuous casting of molten steel is a very important step which involves hi-tech facilities. The flow control is a very important issue that influences the quality of the final products. The parameters of flow control from the tundish into the mold are achieved by means of stopper, taking into account the casting speed, tundish weight, mould and a new generation of submerged nozzle exchange mechanism developed by Vesuvius – SEM 2085 – along with the chemical behaviour refractory component during steel casting

Automatic Settlement System of Liquid Steel Level into the Tundish for Continuous Casting Machine

The increasing quality of steel and a reliability indices of the afferent installations need an automation system for continuous steel casting machines. This paper presents an original solution of automatic settlement of liquid steel debit and level in tundish as well as an analysis of the dynamic behaviour of automatic installation. The results of continuous casting timing satisfy quite all the quality conditions of technological operations: the level variation stands in admissible limits while the records of the level allow the control of installation functions. During all the experiments, the automatic settlement was stable and reliable. The realization of automatic settlement system of liquid steel level in tundish is important for the continuous casting slab quality (under the purity aspect of nonmetalic inclusions) as well as the surface defects avoidance, with efects over productivity of continuous casting machines and cost reduction

An introduction to mathematical models and kinetic simulations of biological processes

Laboratorul Inginerie Tisulară şi Culturi Celulare, USMF "Nicolae Testemiţanu"The function of living cells is controlled by complex regulatory networks that are built of a wide diversity of interacting molecular components. Recent technological developments have enabled single-cell measurements of cellular macromolecules which can shed new light on processes underlying gene expression. Correspondingly, there is a need for the development of theoretical tools to quantitatively understand gene expression and its consequences for cellular processes. The review focuses attention on the necessity of modeling and mentions the basic stages in the mathematical dynamical modeling in biological processes

Mathematical Modeling And Simulation of Photo-Voltaic Converter Operation when Varying Different Parameters

The paper presents a method of mathematical modelling of a solar converter using the results of full-scale testing. The advantages of analytical modelling method applied to photovoltaic systems are also presented; this is because the model parameters are directly measurable by data acquisition from the photovoltaic field consisting of photovoltaic cells type Z - (mono-crystalline photovoltaic). The model parameter also includes both the photovoltaic cell characteristics as a device (forming the photovoltaic field) and the temperature influence on the photovoltaic field performance. The results of the photovoltaic model numerical simulation (PV) to the major parameters conversion variation can also be used to design and assess the performance of low and medium - power photovoltaic systems operating in single regime (to supply the home appliances)

Increase of BOF Converter Life by Own Slag Coating

This paper presents a method for the improvement of the lining life of the BOF converter by slag coating, under nitrogen pressure. Own slag coating of converter lining is put in practice after steel tapping. Dolomite blocks are used like standard wear converter lining. Nitrogen blowing for own slag coating is carried out by oxygen lance. After steel tapping without slag, the converter is tilt in blowing position and the oxygen lance is let down in the lowest position. The nitrogen is blown under 10-12 barr pressure and 450-500 Nm3/min rate, for 3 minutes. By this slag coating technology the performance of refractories has been improved from about 370 heats per campaign in reference year to about 800 heats per campaign at the end of two years of experiments, and therefore refractory consumption decreased from 5.25 kg/t under 3.00 kg/t and the cost of converter refractories decreased by 0.24 $/t. Another variant for improvement of the BOF converter lining life was the use of magnesia bricks for selective lining areas (trunion rings area and charging mouth). The own slag coating technology has been used also. In the case of this variant, the lining life of converter has been improved to about 800 heats per campaign at the end of two years of experiments and so the refractories consumption decreased under 2.45 kg/t. Because of the higher price of magnesia bricks and of the lower price of dolomite blocks, the cost for converter refractories has decreased only by 0.02$/t

Mathematical Modelling of Steel Continuous Casting Hydrodynamics (1)

The quality increase of steel continuous casting and a reliability indices of afferent installations imposes the automation systems adoption of machines of continuous casting of steel. In this paper enters original solution of automatic settlement of liquid steel debit and level in tundish and analyses the behaviour in dynamics behaviour of automatic installation

A Tribological Model for Continuous Casting Equipment of the Steel

This paper presents a coupled thermo-elastic contact problem with tribological processes on the contact interface (friction, wear or damage). The unilateral contact between the cilindrical roll system and a deformable foundation (slab, bloom, etc) is modeled by the Kuhn-Tucker (normal compliance) conditions, involving damage and/or wear effect of contact surfaces. The continuum tribological model is based on gradient theory of the damage variable for studying crack initiation in fretting fatigue [11], [14], [15] , and the wear is described by Archard’s law. The friction law that we consider is a regularization of the Coulomb law. The weak formulation of the quasistatic boundary value problem is described by using the variational principle of virtual power, the principles of thermodynamics and variational inequalities theory. Thus, the main results of existence for weak solution are established using a discretization method (FEM) and a fixed-point strategy [5]

The Structural Optimizing of Metallurgical Installations and Mechanisms

The structural optimizing of used mechanisms in the machines construction and metallurgy through the further liberty degrees creation is essential projection problem, as it enters the closing mechanisms case with sliding case for steel teeming ladles