Slab curvature compensation in a hot rolling mill by means of fuzzy control
In the flat products steel industry, the hot rolling mill transforms the incoming slabs in a thin coil which then can be processed to obtain the final products. Thickness is reduced by pulling the plate between two parallel rolls while moving the upper work roll. The effect of uneven thickness at both sides can produce deviations in the longitudinal direction of the slab, which have to be manually compensated for an human operator. In this paper a multivariable control system and a fuzzy control system are described and compared. Results are illustrated with real data from ACERALIA STEEL CORPORATION.
Способ согласования нагрузок электроприводов горизонтальных валков клети толстолистового прокатного стана
This paper overviews recent advancements in research into the emergence of frontal upward bends; it also covers papers on the distribution of load between the electric drives of upper and lower rolls in horizontal platemill stands. The bulk of research lacks appropriate emphasis on the alignment of these systems. The paper dwells structuring a speed regulator for Mill 5000, which is a platemill; the regulator runs load distribution and frontal upward bending algorithms. The paper substantiates the need to research their parameters for the purpose of better alignment. It presents oscillographs of upper- and lower-roll torques that prove the load is non-uniform in any roughing pass. The paper also analyzes the oscillographs of speeds and torques in a single pass. The existing speed configuration is shown to cause the lower-roll torque to reach its limits, whereas the upper-roll drive switches to the generator mode. The authors propose and validate a set of solutions to address these challenges. They herein present a load regulation method based on forced alignment of upper- and lower-roll drive speeds by disabling the integral part of the load distribution controller. An algorithm based on this method has been implemented in the APCS of Mill 5000; the resultant oscillographs prove better accuracy and shorter time to align the torques. It is herein recommended to apply the research results in the real-world setting.
New Alumosilicate Fillers Based on Sedimentary Rocks for Asphalt Concrete
Asphalt concrete is the most common material for highway and motorway construction. The quality of asphalt is determined, to a large extent, by properties of asphalt binder. Fillers, which are mineral powders from carbonate rocks and aggregates fines, such as limestone and dolomite, are often used in the composition of bitumen mastics affecting the performance of asphalt. This article explores the feasibility of using the fines of aluminosilicate sedimentary rocks as fillers. These materials are composed of clay minerals, which change their properties upon the contact with water. Normally, the use of such fillers is restricted because of poor water resistance and swelling of asphalt concrete. In order to improve the performance of these fillers, the thermal modification at moderate temperatures of 500–600 C has been proposed. Such treatment provides sufficient structural stability of obtained materials and results in the reduction of water absorption of asphalt, improved water resistance (up to 2.5 times) and also, in reduced swelling (up to 9 times). It has been demonstrated that improvement in the filler performance can be achieved by a heat treatment. Such treatment induces changes in the mineral composition and converts the structure of clay minerals into the frame structure of zeolite, as confirmed by X-ray diffraction and infrared spectroscopy. Due to thermal treatment, there is a change in the acid-base properties of the surface of the filler, which is reflected in the profiles of the main adsorption centers. As a result, due to chemisorption, the modified aluminosilicate fillers are able to interact with bitumen. The application of new filler materials in asphalt concrete enables to enhance the performance.