Bloom Continuous Casting Research Articles

Finite Element Analysis of 3-D Electromagnetic Field in Bloom Continuous Casting Mold

Three-dimensional finite element model of electromagnetic stirrer was built to predict magnetic field in a bloom continuous casting mold for steel during operation. The effects of current intensity, current frequency, and mold copper plate thickness on the magnetic field distribution in the mold were investigated. The results show that the magnetic induction intensity increases linearly with the increase in current intensity and decreases with the increase in current frequency. Increasing current intensity and frequency is available in increasing the electromagnetic force. The Joule heat decreases gradually from surface to center of bloom, and a maximum Joule heat can be found on corner of bloom. The prediction of magnetic induction intensity is in good agreement with the measured values.

Fluid Flow in A Four-strand Bloom Continuous Casting Tundish with Different Flow Modifiers

Fluid flows in a four-strand tundish for bloom continuous casting have been investigated with physical modeling and mathematical simulation methods. The liquid steel flow velocity fields in the former tundish and the optimal one with a turbulence inhibitor and newly-designed baffles were numerically calculated and the flow characteristics in the two cases and other tundish configurations were measured in the physical modeling. The results in the physical modeling experiments showed that large difference in the Residence Time Distribution (RTD) curves of two outlets in one side of the former configuration tundish existed. It was found from the numerical calculation of the velocity fields in the tundishes that with the former tundish configuration velocities and turbulent degree of the liquid steel flow in the impact zone of the tundish were large due to the high velocities of liquid steel from the long shroud of the ladle, which caused in lining corrosion and slag entrapment due to the surface eddies. Asymmetric velocity field in the tundish with the former baffles formed and short circuit flow existed in one side of the four-strand tundish. For the optimal configuration of the tundish with a turbulence inhibitor and newly-designed baffles, very similar RTD curves of the two outlets in the same side of the tundish were achieved. The velocities and turbulent degree in the impacting zone of the tundish were depressed and quiet and symmetric molten steel flow was obtained. Eddies on surface and short circuit flow in the optimal tundish disappeared. Such improvement of liquid steel flow in the tundish would increase the ability of inclusion removal. Turbulence inhibitors should be used with other well-designed flow control devices for effective improvement to fluid flow characteristics in tundishes.

Optimisation of baffles in six strand round bloom continuous casting tundish: a physical modelling study

Physical modelling using water in a one-third scale model was carried out to ascertain the influence of various types of baffles with inclined holes on the liquid flow in a six strand round bloom continuous casting tundish. To characterise the flow in the tundish, residence time distribution (RTD) curves were measured for different types of baffles with inclined holes. Because there is no well known analysis model to characterise the melt flow in multistrand tundishes, a new model was presented to analyse RTD curves and its reasonability was discussed. Furthermore, a new approach for quantifying the similarity among the strands was proposed and the baffle was optimised to improve the inclusion floatation and strand similarity in the tundish.

Effect of complex electromagnetic stirring on inner quality of high carbon steel bloom

To obtain a better internal quality of high carbon steel bloom, complex electromagnetic stirring combined M-EMS with F-EMS was designed. In order to find a proper location for positioning the F-EMS stirrer, the solid shell thickness profile of a continuous casting bloom was computed. It was found that the F-EMS stirrer should be placed 11.39 m below the meniscus. Based on the finding, an industrial plant trial was conducted on the operating bloom casting machine at Baotou Iron and Steel (Group) Corp. The results show that the problem of inner porosity and composition segregation can be solved with the complex electromagnetic stirring technique. The ratio and index of central segregation and porosity can be reduced significantly. Therefore, good casting technique, optimum mould design and final electromagnetic stirring are all important for improving the inner quality of high carbon steel.

Improvement in center segregation of high carbon Steel continuous casting blooms

The optimum application of the in-line soft reduction process on the bloom caster makes a remarkable improvement in the macrostructure and in the center segregation of solute Chemical components, without the occurence of internai cracks. This improvement on as-cast blooms contributes to the increase in the toughness in the center part of bar and to the homogeneization of hardness on the cross section of high carbon wire rods.

Reducing the sticking of continuous-cast blooms during heating in continuous furnaces

Reducing the sticking of continuous-cast blooms during heating in continuous furnaces

Effect of secondary cooling on the quality of continuous cast blooms

Effect of secondary cooling on the quality of continuous cast blooms

Introduction of production technology for and efficiency of use of continuous-cast blooms 300 � (1650?1850) mm in cross section

Introduction of production technology for and efficiency of use of continuous-cast blooms 300 � (1650?1850) mm in cross section

Development of low aluminum and nitrogen continuous cast steels for bar and wire rod.

Continuously cast low Al and N steels have been developed as mild steels for bar and wire rod applications. Al content is controlled, using R-H degassing process, from 0.003 to 0.01% not only to minimize Al2O3 inclusions but also to prevent the subsurface blow holes in the bloom section. N content is also reduced under 0.003 % by the hard-blowing of LD process and shrouding during casting.Compared with rimmed steel wire rod, this new steel shows better drawability and higher ductility of wire at the high speed continuous drawing. On the cold forming test the surf face and center of this steel has shown the higher ductility. At higher annealing temperature the, ferrite grain of this Al-killed steel tends to grow suddenly. B addition is effective to the prevention of the abnormal grain growth and brittle behavior of annealed products. Because of the high cleanliness and this segregation of continuous cast bloom, the size and amount of inclusions are smaller and hence the machinability of this steel is poor. Higher S content is desirable for improving it. In addition, the depth of carburization is relatively small. However B addition increases the austenite grain size and hardenability of carburized products.

Mechanism of formation of the V-shaped segregation in the large section continuous cast bloom.

A V-shaped segregation, found in a sulfur print of longitudinal strand section, has been macroscopically investigated. A simple model, using polyethylene particles of 2mm diameter, has been prepared to simulate formation of the V-shaped segregation.The results obtained are summarized as follows:(1) The V-shaped segregation is observed only in an equiaxed crystal zone very periodically along the casting direction.(2) The frequency of the V-shaped segregation becomes smaller, while its density becomes larger with increase in the thickness of the equiaxed zone.(3) The mechanism of formation of the V-shaped segregation may be explained as follows; The enriched liquid between the equiaxed crystals is sucked and flows downwards and is accumulated along the planes which are made by the forcible movement of the equiaxed crystals piling in the end of the solidification regions toward the strand center.(4) The periodicity of the V-shaped segregation is quantitatively explained by the rheological approach assuming the equiaxed crystals piling in the end of the solidification regions as cohesive particles.

A Computer Control System of the Reheating Furnace for Continuous Cast Bloom

Since August 1981, a new computer system has been applied to the reheating furnace for the continuous cast bloom at Kobe Works. This system has been developed for the purpose of saving energy, quality control and automatic operation. The newly designed 5-zoned furnace is equipped with independently-operated walking beams at each zone and blooms are normally hot-charged. In the newly developed system, an optimal heating pattern is determined by on-line calculation in order to minimize total fuel consumption. The technique of minimizing fuel consumption is realized by means of the linear programming method. The bloom temperature is calculated by using the two-dimentional heat transfer equation, and is controlled to coincide with the heating pattern by regulating the setting values of the furnace temperature. Operating results show that fuel consumption is reduced to 600 x 103 KJ/T which is 10% less than that of manual operation. The cast blooms are transported fully automatically from the continuous caster, charged into the furnace, heated up and extracted.