Important Aspects of Continuous Casting of Billets Mar31

Important Aspects of Continuous Casting of Billets...

Important Aspects of Continuous Casting of Billets Continuous casting of steel billets is an operation which is sensitive to a number of factors. It is to be performed with adequate controls and with steadiness and in such a way so as to produce safe casting product with sound steel mechanical properties, and to ensure a continuous process with limited delays. The process requires good control of operating parameters in order to produce sound and continuous billets. Important aspects of the continuous casting of billets are (i) quality of the billets, (ii) productivity of the machine, and (iii) cost of production. There is necessity to optimize the performance parameters to achieve high productivity and required billet quality with decreasing operating costs. The machine availability and the process reliability are the important factors during the continuous casting of the billets. The continuous casting of billet is a highly flexible process in which the operator is to react to changing requirements extremely quickly. The steel qualities needed from a billet continuous casting machine range from simple construction steel (rebar) to state-of-the-art ‘special bar quality’ (SBQ) for the automotive industry and other engineering applications, as well as high grade wire products such as soft-steel wires, pre-stressed concrete reinforcing wire, and tire cord. During the continuous casting, the quality of cast steel billets, thermal stress, surface defects and cracks formation are highly dependent on the temperature distribution along the entire continuously cast billet. The main attention is usually paid to the surface temperatures and particularly to the corner temperature distributions. However, from the technological point of view the temperature distribution in the core of cast billet, which is highly related to the metallurgical length and to the unbending process, is very important as well. Therefore, monitoring of temperature field...

Historical aspects of the Continuous Casting and related Technologies for Steel Mar06

Historical aspects of the Continuous Casting and related Technologies for Steel...

Historical aspects of the Continuous Casting and related Technologies for Steel Continuous casting (CC) technology of steel, as a method of solidification processing of liquid steel has a relatively short history —not much longer than oxygen steelmaking. Different to other processes in steel production, continuous casting is the vital link between the liquid and the solid phase and has to live with metallurgical effects as well as mechanical challenges at the same time. Continuous casting transforms liquid steel into solid on a continuous basis and includes a variety of important commercial processes. These processes are the most efficient way to solidify large volumes of liquid steel into simple shapes for subsequent processing. The CC ratio for the world steel industry is now around 96 % of crude steel output which was a mere 4 % in 1970. Continuous casting is distinguished from other solidification processes by its steady state nature. The liquid steel solidifies against the mould walls while it is simultaneously withdrawn from the bottom of the mould at a rate which maintains the solid / liquid interface at a constant position with time. The process works best when all of its aspects operate in this steady-state manner. Relative to other casting processes, continuous casting generally has a higher capital cost, but lower operating cost. It is the most cost- and energy- efficient method to mass-produce semi-finished steel products with consistent quality in a variety of sizes and shapes. Cross-sections can be rectangular, for subsequent rolling into plate or sheet, square or circular for long products and seamless pipes, and even dog-bone shapes, for rolling into I or H beams. Today continuous casting machines consist of modularized technological/mechatronic packages to allow fast design and short project execution time as well as rapid production ramp-up...

Protection of Environment in an Integrated Steel Plant...

Protection of Environment in an Integrated Steel Plant  The processes of an integrated steel plant are highly resource intensive, consequently emitting and discharging pollutants and therefore, the cause of environmental concerns. They have a variety of impacts on the environment. The main impacts come from the use of energy and raw materials, which result in emissions such as carbon dioxide (CO2), sulphur oxides (SOx), nitrogen oxides (NOx), dust emissions to air. Water is used throughout the plant for cooling or heat transfer of heat processing equipment. Water is also required for descaling, dust scrubbing, quenching and other processes. Direct contact water gets contaminated during use and when this contaminated water is discharged from the plant, it impacts the environment. Also solid wastes generated during the plant operations, need dumping in the land filling area. These wastes also have its effects on the environment. One more factor which affects the environment is the noise which is produced during the plant operations. In short, thera are four types of pollutants which are affecting the environments (Fig 1). These are (i) air emissions, (ii) liquid effluent discharges, (iii) solid waste dumping, and (iv) generation of noise. Fig 1 Types of pollutants affecting environment The steel plant is required to be in compliance with regulations for meeting both generic standards for air, water, noise, waste management as well as specific standards for steel industry. The plant is required to meet the environmental norms for coke ovens, sinter plant, blast furnace, steel melting shop, rolling mills etc. for stack emissions, fugitive emissions and effluent discharges. It is also to comply with the ambient air quality standards. The steel plant is to take measures to improve its environmental performance not only for complying with the statutory environmental norms but also...

Electromagnetic Stirring in Continuous Casting Process Nov29

Electromagnetic Stirring in Continuous Casting Process...

Electromagnetic Stirring in Continuous Casting Process Since the first application of the principle of continuous casting to steel in the test continuous casting machine of Junghans of former West Germany, the quality of the continuous cast product has been paid more and more attention. In recent years with the stress on the production of clean steels, there are higher requirements for the microstructure and the composition homogenization of the cast product. The chemical composition, solidification conditions and the nature of the liquid steel flow in the mould affects the surface quality and the inner structure of the cast product. The application of electromagnetic stirring (EMS) technique promotes the formation of an equiaxed crystallic zone in the strand. It causes the refinement of the solidification structure, the reduction in the content of inclusions and improvement in the quality of the surface, sub surface and the inner structure of the cast product. Principle of electromagnetic stirring It is well known that an alternating magnetic field (B) (either single phase, two phase or three phase) applied to a conductor, whether solid or fluid, will induce electric current (j) in the conductor, and hence there is a force (F = j x B). This force is known as Lorentz force. Due to the Lorentz force there is a generation of a torque that gives the liquid steel a rotational movement.  The generated torque depends on the following factors. Intensity of supply current Number of windings forming a coil Frequency System geometry These parameters change depending on the stirrer type. Thus the magnetic field acts as a non intrusive stirring device and it can, in principle, be engineered to provide any desired pattern of stirring. The stirrer design, size and position etc. depend on the continuous casting machine data,...

Environment Management System in Steel Plant...

Environment Management System in Steel Plant Environmental Management System (EMS) is a set of processes and practices which enables an organization to manage the impacts of its organizational activities on the environment and also to increase its operating efficiency. It is a framework which helps the organization to achieve its environmental goals through consistent control of its operations. The framework includes organization’s environmental programs in a comprehensive, systematic, planned and documented manner and includes the organizational structure, planning and resources for developing, implementing and maintaining organizational policy for the protection of the environment. It provides a structured approach to planning and implementation of the environment protection measures. However the EMS itself does not dictate a level of environmental performance that must be achieved since EMS of every organization is tailored to meet the business and goals of the organization. Elements of an EMS EMS encourages the organization to continuously improve its environmental performance. The basic elements of an EMS are as follows: The organization commits initially to an environmental policy. It includes review of the present status and future environmental goals of the organization. Analysis of the environmental impacts and the legal requirements. Keeping environmental policy as the basis, the organization sets the environmental objectives and targets for reducing environmental impacts and for complying with the legal requirements. Establishment of plans for improving the environment performance and also for meeting the objectives and targets of the organization. Monitoring, measuring and evaluating the progress for achievement of the objectives. To ensure environmental awareness and competence of the employees of the organization. To take corrective actions if the objectives and targets are not being met. To have regular review of the progress of the EMS and to make improvements on continuous basis. Environment management system standard In...