Wide-strip Rolling Mill Research Articles

Elaboration of forecasting methods of analysis of metallurgical facilities electric drives technical state

To prevent losses of equipment downtime, analytical algorithms and data of automated control systems sensors are used to estimate time to the equipment failure approach. It was shown that modern technical systems, such as automated electric drives are equipped by measuring devices which allow to accomplish self-diagnostic of the system in real time mode at existing methods of data processing and analysis. This approach is more effective than traditional methods of diagnostic and does not include additional capital expenses for specialized diagnostic equipment and personal qualification. Hypothesis of forecasting of electromechanical driving system state was elaborated and checked for continuous rolling mill runaway roller, based on character of loading modes by using only one parameter – the electric motor current. Based on the data analysis of wide strip rolling mill 2000 runaway rollers operation, normalized curves of distribution of average values of the runaway roller drive current at its normal operation and origination of a malfunction were built. It was shown that a technical system state change is fixed at appearance of a deviation of load current distribution comparing with a standard deviation. Analysis of dynamics of a statistical parameter, the standard error (the difference between actual and standard distribution) at a transition process allowed to make a forecast of roller jamming several days before the malfunction took place. The proposed approach of equipment state estimation can become a base for elaboration of a principally new methods of diagnostic of metallurgical rotor equipment.

Stalinism, autarchy, espionage and Marshall Aid: How US strip mill technology came to Europe

The American continuous wide strip rolling mill halved the cost, improved the quality and markedly increased the size of steel sheets after 1926. These mills diffused rapidly in the USA to supply a growing market for autobodies, canstock and consumer goods. European steelmakers adopted this radical, large scale technology during the late 1930’s. Pre-war adopters in Europe briefly interpreted strip mill technology to meet political priorities, market circumstances and local technical preferences. The UK steel industry bought standard mill designs directly from two US suppliers. Soviet and German adoption was shaped by political regimes of the time. The German mill was the product of local innovation and espionage. In France, Renault developed small scale technology. Marshall Aid made post-war adopters conform to US technological norms, with the Cold War influencing the location of strip mills in Europe after 1948. The wide strip mill contributed to the Americanisation of European industry after World War II.

Surface Finish Enhancement of Hot-Rolled Strips on the 2000 Wide-Strip Rolling Mill Using Mathematical Modeling at Novolipetsk Steel

Based on the manufacturing of rolled stock with a high-quality surface finish on the 2000 wide-strip rolling mill at Novolipetsk Steel (NLMK) using a package of mathematical models of energy–power and thermal finish-rolling conditions, the formation mechanisms of morphologically similar mass defects of the “pitted surface” type have been analyzed. The influence of the roll and strip cooling conditions from the rolling temperature conditions has been investigated. The factors that enable the mill scale to be rolled into the strip in the first stands of the finishing train have been identified. The cooling conditions for rolling of critical-duty products have been developed and introduced in the 2000 mill finishing train, which ensured a 36%‑yield reduction of products in 2018 that exhibited the “pitted surface” defect.

Thermomechanical Controlled Rolling of Hot Coils of Steel Grade S355MC at the Wide-Strip Rolling Mill 1700

Тhere has been developed technology, and pilot batch of hot rolling coils (6×1500 mm, steel grade S355MC) has been produced using thermo-mechanical controlled process (TMCP) for the wide-strip rolling mill 1700. The integrated technology for TMCP coil production (steel grade S355MC) has been firstly developed for the rolling mill 1700 in accordance with EN 10149-2. Air cooling for coils to 450°C after coiling has been firstly used in the developed technology, which provides for decrease in air scale and improvement of surface quality for the customers. It is possible to manufacture rolled products up to 6×1500 mm (steel grade S355MC) in accordance with EN 10149-2 using the existing equipment without exceeding the existing process constraints during its operation and without upgrading. It is possible to further master the rolled products, which are manufactured according to the TMCP technology.

Method of load calculation of electrical drives of rolling mills during heavy plate manufacturing

During manufacturing of heavy strips and plates from difficult-to-form steel grades on sheet and wide-strip rolling mills there is a problem of exact calculation of power parameters of rolling. It is pointed out that known methods do not provide required precise information at high deformation zones in a stand. An improved calculation method for rolling pressure and load torque of electrical drive engine is suggested further. This method considers peculiar strain of product in high deformation zones and its accelerated motion in reverse mode. Improved analytical dependences for rolling pressure and load torque of electrical drive are reviewed. Control flow chart and main screen of developed software for calculation of wide- strip rolling parameters are presented. Comparative analysis of calculation data and experimental results of engine equivalent currents during tube steels rolling is made. As a result improved precision of calculation method is justified.

Analytical Model for the Wide-Strip Rolling Mills Working Rolls Wear-Out Failures

The paper proposes a mathematical model for the gradual shape deterioration of wide-strip rolling mills working rolls active generatrixes subject to wear within the working zone during tandem rolling strips of a specified gauge. While modeling, the authors have determined the theoretical dependency needed to estimate the mean life of working rolls according to the transverse strip gauge interference criterion. Gauge interference of tandem-rolled strip transverse section shall be derived from the sum of the values of current shape of upper and lower working rolls active generatrixes, which are calculated based on strip width. In its turn, an active section of each roll shall be calculated for every following strip as a difference between the current roll radius values at the crown middle and that above/below the strip edge, while the shape deterioration rate of active roll generatrixes shall be defined by the difference between the roll wear rates in these sections. To estimate the rate of roll wear during rolling every following strip of the specified gauge, the base dependency of the structure-energy concept describing wear of stationary tribocouplings is used, which has been obtained by simultaneous solution of fundamental equations of molecule-mechanical and structure-energy friction theories. The moment of working roll failure (expected life) is determined based on the condition of achieving the nominal limit by gauge interference of a current strip.

Оценка изнашиваемости рабочих валков чистовой группы НШПС-1700 АО «АрселорМиттал Темиртау»

The decrease of the rolls wear is an important reserve of the improvement of rolling production. At present during rolling metal of all kinds at the wide-strip rolling mill CWRM-1700 by the JSC “ArselorMittal Temirtau” work rolls of the Hi-Cr type are used in stands No. 6–8, whereas work rolls of the ICDP type are used in stands No. 9–12 for finish rolling. Initial and worn profiles of rolls were determined using the instrument ID 05009. Measurements were performed after roll reloading and cooling, mainly before polishing, with the accuracy of ± 0.01 mm. The amount, assortment and steel grades of the rolled metal, as well as diameters, chemical composition and hardness of the rolls were also fixed. In general research permitted to estimate the wear of the work rolls of the finishing group of CWRM-1700 using geometrical, kinematic and energy indicators of wear. The energy indicator is universal since it takes into account the decrease of the body size from unit work of friction forces on unit roll surface. The kinematic indicator takes into account the decrease of the roll radius relative to unit friction path of the roll surface. The change of geometrical wear indicators of rolls with the same properties in different stands makes it necessary to take account of technological factors that were taken into account while calculating kinematic and energy indicators.

Strip shape control capability of hot wide strip rolling mills

The elasticity deformation of rolls was analyzed by means of two-dimensional finite element method (FEM) with variable thickness. Three typical mills were used as objects for analysis. A thorough study was done on the control capabilities of these mills on the strip shape. Then the strip shape control capabilities of the three mills was compared synthetically.

Energy-force parameters of six-high stands in wide-strip rolling mills

A new procedure is developed to compute the energy-force parameters of six-high stands in which a main drive is transferred through intermediate or backup rolls. The rolling force, power, and torque are calculated, and the forces and moments acting between work, intermediate, and backup rolls are determined with allowance for rolling friction and friction in bearings. The procedure developed can be used to calculate the optimum design parameters of stands of this type that provide the minimum capital outlays and energy consumption.

SASS applied to optimum work roll profile selection in the hot rolling of wide steel

The quality of steel strip produced in a wide strip rolling mill depends heavily on the careful selection of initial ground work roll profiles for each of the mill stands in the finishing train. In the past, these profiles were determined by human experts, based on their knowledge and experience. In this research, SASS, a novel heuristic optimisation algorithm that has only one control parameter, has been used to find the optimum profiles for a simulated rolling mill. The best set of profiles found by SASS clearly outperformed the original set and performed equally well as conventional algorithms without the need of finding a suitable set of control parameters.