Rolling Plant Research Articles

Seamless Pipes Manufacturing Process Improvement Using Mandreling

The paper discusses the specific aspects of hot rolled seamless pipes manufacture using pipe rolling plants including screw-rolling mills. The method of accuracy enhancement of pipe dimensions, as well as external and internal surface quality improvement, is proposed. The article specifies the results of computer and physical modeling of the pipes mandreling process. The application of the mandreling process within the cage using different diameter mandrels is shown. We managed to decrease the typical mark caused by the metal deformation, due to the screw-rolling mill and to manufacture pipes with more accurate dimensions, as a result of the mandreling process modeling. The results of the physical experiment on mandreling the shell pierced at the screw-rolling mill showed a positive effect from the process of hollow billet cold treatment using the mandrel.

Pipe rolling plants as a target of economic security in Russia during the COVID-19 pandemic

Subject. The article is an attempt to evaluate how the COVID-19 pandemic influences the economic development in Russia, illustrating the case of the tube rolling industry. Objectives. I examine and evaluate how adverse crisis implications of the COVID-19 pandemic could possibly be eliminated in the tube rolling industry, ensuring the economic security of Russia. Methods. The study involves methods of empirical and theoretical research, such as systems and empirical analysis, formal characterization, abstraction, observation, generalization, assessment, and partial methods of economic and statistical analysis. Results. I generally describe the economic situation during the COVID-19 pandemic, evaluate the impact of ties between the oil and tube rolling industries on the economic sovereignty and security of Russia, role of the tube rolling industry in the economic security of the State. I analyzed the impact of the COVID-19 pandemic on the goods circulation in the tube rolling industry and found probable implications of economic destruction for Russia due to the COVID-19 pandemic, and proposed possible solutions for the tube rolling industry. Conclusions and Relevance. The economic security of the tube rolling industry during the current pandemic is exposed to the destruction of foreign trade between countries exporting tube rolling products, price drop and a reduction in the consumption of energy resources worldwide, capital flight, a decrease in labor resources, slowing business activity and restricted transportation tube rolling products, growing uncertainty on the consumption of tube rolling products. The menacing threats can be eliminated given the State intervenes and regulates the Russian tube rolling industry so as to create favorable conditions for the beneficial economic operations.

An artificial intelligence approach for the in-line evaluation of steels mechanical properties in rolling

The large demand of high-performance steels to improve the safety and energetic performances in automotive is driving the increasing need of higher uniformity of mechanical properties of rolled products, both within a single coil and in large batch productions of multiple coils. To achieve these targets, we are witnessing an evolution of rolling towards the introduction of sensors and Artificial Intelligence (AI) algorithms to allow the real-time monitoring of both the strip tensile properties and the evolution of microstructure during the annealing process. The work described in the paper is part of a research work that is aimed at developing an AI framework that could allow the full real-time control of the entire mill rolling plant thanks to (i) innovative sensors applied at different steps of the coil processing, (ii) mixed analytical and numerical algorithms for the data computation and analyses, and (iii) IT infrastructure to collect and elaborate the data. The focus of the paper is on the tension-levelling operation which is one of the first that is performed in the rolling mill and can have a relevant influence on the strip mechanical characteristics. To reach this aim, a predictive model applicable to the tension-levelling process was developed, as this process is used to minimize flatness imperfections and residual stresses by means of plastic deformation. During the process, the material is subjected to cyclic tension-compression stresses, obtained with repeated and alternate bends under superposed tension. Consequently, the desired product standards, in terms of thickness and flatness, are achieved, while the mechanism of deformation changes the final mechanical properties of the material, increasing the yield strength and decreasing the maximum elongation. Finally, the predictive model is used to predict the coil mechanical characteristics, by using the data sampled from the sensors placed inside the tension-levelling machine.

Experimental Study of Features of Thin-Walled Pipes Sizing in the Line of a Pipe Rolling Plant with an Automatic Mill

The aim of the study is to establish the actual level of working loads on the roll drive line of the sizing mill installed as part of the PRP-220 with an automatic mill, when switching to the production of steel pipes from increased strength group. The study is based on a complex experimental and theoretical analysis. After the processing of the results of experimental studies a comparison of the most loaded sizing route for a thin-walled pipe with a diameter of 244.5 mm and a wall thickness of 8.9 mm (D/S = 27.5) made of steel of strength group “D” was made with the route for a pipe with a diameter of 177.8 mm and a wall thickness of 9.2 mm (D/S = 19.3) from steel of strength group “E”. Graphs of the observed processes are presented, as well as calculated predictive values of sizing of thin-walled pipes for steel of strength group “E”, obtained on the basis of an experimental-theoretical analysis of the growth of flow stress. Recommendations have been given for improving the equipment of the PRP-220 sizing mill for the production of pipes with increased diameters from steels of increased strength groups.

Zero Liquid Discharge (ZLD) Industrial Wastewater Treatment Systems as Sustainable Development Basic Ecological Components

The problems in processing the acid ferrous-containing rinsing water and spent pickling solutions are considered. The first-ever in metallurgy zero liquid discharge (ZLD) industrial wastewater treatment systems of a transformer cold rolling plant at the Verkh-Isetsky steelworks in Sverdlovsk (now — LLC VIZ Steel is a part of Novolipetsk Steel Group of Companies) is described. The experience of the VIZ Steel, particularly in relation to industrial wastewater treatment and sludge processing, is useful for designing ZLD industrial wastewater treatment systems of metallurgical, machine-building and metalworking enterprises. The recommendations for organizing the ZLD industrial wastewater treatment systems in the pickling plants with the repeated use of the treated rinsing water and processing the spent pickling solutions and the sludges are presented. For practical calculations of clarifiers the empirical formulas are offered. Process flow diagram of acid ferrous-containing rinsing water treatment is suggested. Acid ferrous-containing rinsing water treatment includes the following processes: rinsing water neutralization to pH 9-10,5 by 5 % calcium hydroxide and partial ferrous oxidation by air; addition of anionic flocculant and active gypsum priming to the neutralized rinsing water; settling of rinsing water conditioned by reagents in clarifiers; treatment of clarified water on deep bed sand filters; reclaimed water treatment.

Studying the process of pipe reeling based on the monitoring of the drive’s loading parameters

The goal of the study was to establish the actual level of loads on the principle lines of the reeling mills mounted in the pipe rolling plant TPA 220 in the conditions of change the production release to the steel with the increased strength grade. The method of the study was the complex theoretically and experimental analysis.In the article the data of the loading limits on the principle lines of the reeling mills end their electric drives is set forth. The results of the experimental studies were processed for the most loaded route of rolling the pipe with the diameter 245 mm and the wall thickness 8.9 mm for the steel grade K55. The oscillograms of the observed processes and the calculated predictive oscillograms for the steel grade N80 have been presented which were obtained based on the theoretical and experimental analysis of the growth of the metal’s flow stress.

Dynamic rolling model based on uniform deformation

Abstract Accurate prediction of rolling force is a core point during the hot-rolled strip production. In-depth research on static rolling processes has been carried out in the past. Most models, however, can only be used under static conditions. Therefore, it is challenging to research the dynamic rolling process. This paper presents a dynamic rolling model for hot rolling. Firstly, the strip dynamic velocity model and the dynamic boundary condition model are established, and then the total power equation of the dynamic rolling process is solved based on the energy method. Furthermore, by minimizing the total power function, the dynamic rolling force equation can be obtained. Finally, the effectiveness of the proposed dynamic model is verified by hot strip rolling plant experiments and finite element simulations. The results show that the dynamic model of this paper has higher prediction accuracy and can be applied to the research on the dynamic hot rolling process. Besides, the influence of the vertical velocity of the rolls on the dynamic rolling force and influencing factors of dynamic rolling force are discussed.

Effect of Cambered and Oval-Grooved Roll on the Strain Distribution During the Flat Rolling Process of a Wire

The effect of the roll design on the strain distribution of the flat surface, lateral spreading, and the strain inhomogeneity of a flat-rolled wire were investigated during the flat rolling process. Oval-grooved and cambered rolls with various radii were applied to the flat rolling process based on a numerical simulation. The effective strain on the flat surface of the wire increased when using a cambered roll due to the highly intensified contact pressure on the flat surface, while the effective strain on the flat surface of the wire decreased when using an oval-grooved roll. Lateral spreading decreased when using an oval-grooved roll because the spread in the free surface area of the wire was highly restricted by the oval-grooved roll shape. In contrast, the spread in the surface area increased when using a cambered roll due to the less-restricted metal flow at the free surface. Accordingly, a cambered roll with a small radius is highly recommended in order to improve the surface quality of flat-rolled wires. This is beneficial for industrial plants because the cambered roll can be easily applied in flat rolling plants.

CAD Based Electric Transporter Path Planning and Production Storage Optimization Using Genetic Algorithm – Industrial Case Study

Štore Steel Ltd. is one of the largest flat spring steel producers in Europe. There are two production lines after rolling – one for flat bars and the other for round bars. The flat bars production generally consists of visual examination, straightening and cutting operation. In addition, heat treatment or magnetic particle testing could be conducted. On the other hand, the round bars production consists generally of straightening, automatic control line control, chamfering and cutting. In addition, heat treatment is possible. For manipulation of the material in the rolling plant, the electric transporter and several cassettes are used. In the paper path planning and production storage optimization (i.e. storage spaces for cassettes) were conducted using genetic algorithm. The production storage is actually the space between main transport passage and individual operations. In the research the universal system using CAD geometry is presented where AutoCAD environment and in-house developed AutoLISP system were used. The production storage – storage spaces for cassettes (location and orientation) with corresponding electric transporter trajectories are represented as CAD objects and thus form individual solution/organism. The organisms undergo simulated evolution. The results of the evolution are compared with actual production storage in the steel plant.

Применение программного комплекса ANSYS для электромагнитного и теплового анализа электродвигателя привода пильгерстана технологии изготовления бесшовных труб

Currently, the metallurgical production contains a large number of morally and physically outdated electrical equipment that requires modernization. Large capital expenditures are required to replace it. For this reason, it is slow to implement, long-term use for the purpose of payback, and slowly decommissioned. In this regard, the new equipment should be innovative and in many ways ahead of the existing level of development of the industry. The article offers such a solution for the company PJSC «Chelyabinsk pipe rolling plant». To replace the existing collector motor of the pilger mill drive for the manufacture of seamless pipes, which has been operating since 1928 and is in critical condition, a large-size low-speed valve motor with a large built-in inertial mass, having a permanent magnet magnetic system and claw-poles, is proposed to replace the existing collector motor of the pilger mill drive for the manufacturing of seamless pipes, which has been operating since 1928 and is in critical condition. Such a technical solution for drives of this class has not been used in the world. The motor eliminates the existing 120-ton flywheel, improves reliability due to contactless current supply, and reduces operating costs by eliminating excitation losses. The design of the engine allows its assembly without additional technological equipment, which is very important for large engines with permanent magnets. To develop a unique motor, a design system consisting of a synthesis subsystem and an analysis subsystem was created. The synthesis subsystem implements multi-level single-criteria optimization. As a result of its work, the optimal geometry is determined according to the selected criterion. The analysis system confirms the accuracy of the calculation using simplified optimization methods and finally removes technical risks before manufacturing an industrial design. It is based on the Ansys Electronics Desktop and Ansys Icepak systems that are well-developed for CAE electric machines. The analysis has several stages and includes electromagnetic and thermal analysis. The proposed design system is tested on a real project and implemented as a calculation of the magnetic and thermal state with dynamic load in JSC «Russian electric motors»

Factors Influencing the Quality of Decision-Making Using Business Intelligence in a Metal Rolling Plant in KwaZulu-Natal

Factors Influencing the Quality of Decision-Making Using Business Intelligence in a Metal Rolling Plant in KwaZulu-Natal

P.691 Impairment of the process of thinking on different stages of schizophrenia in connection with the magnocellular and the parvocellularneural systems

Accurate prediction of rolling force is a core point during the hot-rolled strip production. In-depth research on static rolling processes has been carried out in the past. Most models, however, can only be used under static conditions. Therefore, it is challenging to research the dynamic rolling process. This paper presents a dynamic rolling model for hot rolling. Firstly, the strip dynamic velocity model and the dynamic boundary condition model are established, and then the total power equation of the dynamic rolling process is solved based on the energy method. Furthermore, by minimizing the total power function, the dynamic rolling force equation can be obtained. Finally, the effectiveness of the proposed dynamic model is verified by hot strip rolling plant experiments and finite element simulations. The results show that the dynamic model of this paper has higher prediction accuracy and can be applied to the research on the dynamic hot rolling process. Besides, the influence of the vertical velocity of the rolls on the dynamic rolling force and influencing factors of dynamic rolling force are discussed.

Investigating the thermal work and construction of annular furnace on “Chelyabinsk pipe-rolling plant” PJSC to improve heat technical indicators of its work

High performance of rolling and tube rolling mills, good quality of finished metal products can be obtained by heating metal billets with minimal oxidation and decarburization in heating furnaces. Such conditions can be provided by annular furnaces, which are widely used in the rolling production of pipes, railway wheels and tires. High-quality heating allows us to obtain the structure of metal products with given thermal and working properties, as well as the plasticity necessary for subsequent mechanical processing. In this paper, we consider thermal engineering features of the operation of an annular furnace for heating billets before rolling at “Chelyabinsk Tube Rolling Plant” PJSC (ChTPZ). The problems arising during the operation of thermal unit were analyzed: high specific fuel consumption for billets heating; high temperatures of walls external surfaces and roof external surfaces; low heating rate of the billet; large amount of air leaks into the furnace working space. Also design of gas-burning devices does not provide the possibility of regulating gas supply in a large range of loads, up to a periodic complete shutdown. And thermal energy of waste gases is practically not used. Metal heating has been analyzed and annular furnace heat balance has been compiled. Analysis of the results of computational studies has revealed factors that reduce energy efficiency of the existing furnace design. The measures were proposed for its modernization in order to reduce fuel consumption and to increase productivity (use of fibrous refractory materials, regenerative burners, non-water-cooled partitions, etc.). To assess impact of the proposed measures, the furnace heat balance after its systems reconstruction and assembly has been compiled, the main indicators of the furnace heat operation have been determined. When implementing proposed measures, significant economic effect is expected, including improvement in quality of metal heating while reducing fuel consumption and increasing productivity of the unit. In particular, after furnace reconstruction it is expected to increase the total (by 18.1 %) and heat (by 31.0 %) efficiency of the furnace, and to decrease (to48.3 kgconditional fuel/ton) specific fuel consumption.

Application of neural networks for predicting hot-rolled strip crown

In this paper, a prediction model for hot-rolled strip crown based on an artificial neural network (ANN) is presented. Considering the mean squared error (MSE) and correlation coefficient (R), production data of 10,133 coils collected from a hot rolling plant are used to establish models. A feed-forward neural network with one hidden layer, a non-dominated sorting genetic algorithm II (NSGA II) optimized ANN, and a deep neural network (DNN) are applied to evaluate the prediction performance. Parameter settings of the ANN and NSGA II including learning rate, hidden neurons, activation function and population size, and crossover probability, are investigated to acquire the optimal model. The structure of the DNN, including how many layers and units the network should contain, is also studied. Prediction performance comparisons of the ANN, NSGA II-ANN, and DNN are presented. Among the ANN, NSGA II-ANN and DNN, the results show that the DNN has the highest prediction accuracy. Root mean squared error (RMSE) of the proposed DNN is 2. 06μm, and 97.04% of the prediction data have an absolute error of less than 5μm. Through model response surfaces, effects of four key operating parameters are investigated. The results indicate that the proposed DNN with strong learning ability and generalization performance can be well applied to hot rolling production.

Study on Thermal Operation and Design of Ring Furnace of the Pipe Rolling Plant

High productivity of rolling and pipe rolling mills, good quality of finished metal products is possible to provide in the presence of powerful heating furnaces, well heating the metal with minimal oxidation and decarburization. Such conditions are provided by ring furnaces which are widely used for heating the preparations at rolling of pipes, wheels and bands of the railway rolling stock. The purpose of the heat – receiving structure of the metal, providing a set of physical and working properties, or impart to these materials the ductility required for subsequent machining. The article deals with the design and thermal performance of the ring furnace operating at ChelPipe’s Pipe Rolling Plant No.2. The problems arising during the operation of the thermal unit are analyzed. The paper describes the calculation of heating of metal and heat balance of the ring furnace. In the course of the analysis of the results of design studies, the shortcomings of the existing heat recovery system are revealed and measures for the reconstruction of the furnace to reduce fuel consumption and increase productivity (replacement of the existing brick lining with fibrous, the use of regenerative burners, the use of non-water-cooled partitions, etc.) are proposed. The paper analyzes the design and thermal performance of the ring furnace for heating of pipe billets before rolling. It shows a heat balance of the ring heating furnace and provides measures for furnace reconstruction aimed at reduction in fuel consumption and increase in efficiency: replacement of the existing lining with fiber lining, use of regenerative burners, application of non-water cooled walls.

Optimization Technology of Roll Contours during Skin-Pass Rolling Process of Hot-Rolled Strip

The hot-rolled strip skin-pass mill is the important technological equipment of finishing process in the hot rolling plant, and its role is to apply a slight thickness reduction of approximately 1% - 4% to the finished products cooled to room temperature to repair flatness defects and improve the surface quality and mechanical properties. In this study, the initial flat roll contours were optimized to solve some problems such as the serious and non-uniform wear of work rolls and the poor shape control abilities of the strip. A three-dimensional rolls–strip coupling model of hot-rolled strip skin-pass mill was established using the nonlinear finite element software ABAQUS. The effects of the roll contours on the contact pressure between rolls and the control effect of bending forces were analyzed, and a variable contact-length backup roll (VCR) contour configured with a positive crown contour for work rolls was proposed. Compared with the initial flat roll contours, the average replacement cycle of work rolls for the optimized roll contours increased from 465.4 tons to 701.3 tons, the non-uniform wear amount was reduced by nearly 15%, and the adjustment ratio of the negative bending forces decreased from -100% to -40% by industrial experiments in the 1580 mm single-stand four-high hot-rolled strip skin-pass mill.

Asymmetric hydrodynamic roll gap model and its experimental validation

In tandem hot strip rolling mills, different friction between the rolls and the strip material on the upper and lower strip surface can occur due to asymmetric surface temperatures or different conditions of oil lubrication. To capture these effects, this paper presents a hydrodynamic roll gap model with asymmetric friction. Based on similarities between the rolled material and viscous fluids, fluid mechanics theory is used to derive this model. Due to the nature of this model, the influence of the rolling speed is inherently taken into account, which allows an accurate prediction of the rolling force and the forward slip. As an analytic solution for the hydrodynamic roll gap model is available, it is well suited for online applications in rolling plants. For validation of the proposed model, an experiment with asymmetric work roll roughness was performed. A specimen of steel strip with copper pins inserted was repeatedly rolled to visualize the material flow inside the roll gap for multiple passes. The resulting deformed copper pins were cut out of the strip and show good agreement with the deformation profiles calculated by the developed model.

RESEARCH OF THE BEHAVIOR OF MACROSTRUCTURE DEFECTS OF THE PRE-DEFORMED CONTINUOUS CAST BILLETS DURING ROLLING

The most significant trend in recent decades in the field of continuous casting of steel billets is a partial transfer of the process of deformation of the exposure to the field of complete solidification (rolling mill) in the area of two-phase (solid-liquid)state (technological line of CCM). However, the implementation of such two-stage deformation of the continuous cast ingot leads to the need for changes to the methodology of physical simulation of the behavior of defects (surface and bulk) in the course of the subsequent rolling, first and foremost, in terms of the correct choice of their geometric shape and spatial orientation. The paper presents the results of a study of the influence of spatial orientation of the surface defects and continuity of the macrostructure of the metal axial region deformed in the line of the continuous casting machine using layered physical models. An experimental study performed in the conditions of deformation of reduced billets by two schemes with rolling simulation scale1:5: in smooth rolls, simulating the process of groоvelles rolling as applied to the first two stands of the crimp group of medium-section mill 300; in the first and second pairs of rectangular grooves of breakdown stand of the mill 500/370 of PJSC “Donetsk Metal Rolling Plant”. According to the multiplicity of the problem, the universal design of physical models was developed to simulate the spatial location of both surface and internal defects. Studies have shown that in case of rolling of physical models with extract ratio over 2.0 and an angle of misalignment defects imitators close to 60° their complete “healing” is possible. In turn, decrease in the angle to 30° contributes to greater extraction of the defect-simulator and only a small decrease in their width. In the case of total misalignment of defect-simulators (angle 90°) there is a broadening of the defects and their deposition to the initial length after tilting by 90°. The obtained experimental data allowed understanding of the mechanisms of “healing” defects integrity of metal depending on magnitude of the total extracts, the angle of misalignment of the longitudinal axis of the defect with the rolling direction and the distance of their occurrence from the longitudinal-transverse plane of symmetry.

Mathematical model of lever arm coefficient in cold rolling process

The prediction precision of mechanics parameters such as rolling force and torque affects the yield, quality, cost, and benefit of products during the cold strip rolling. The lever arm coefficient is the core linking rolling force and torque, but there is no mathematical model of this in cold rolling. The distribution of rolling pressure and the change rule of lever arm coefficient under different reduction, forward and backward tension stress, deformation resistance, and friction coefficient in cold rolling are illustrated based on 3D (three-dimensional) elastic-plastic FEM (finite element model) simulation. The mathematical model of lever arm coefficient is built according to online measured data processed by BP (back propagation) neural network in the tandem cold rolling plant. The predicted rolling forces calculated on the basis of this model and upper bound method are consistent with online measured values. The proposed model provides valuable guidelines to determine the reduction and check the strength of the equipment such as rolls and stands.

Future Challenges in the Steel Industry and Consequences for Rolling Plant Technologies

This paper provides an overview of recent steel market developments considering also the global steel oversupply as well as the installed and planned capacity as recessions in some emerging economies. Especially the enormous Chinese investments combined with their actually decreasing demand are a major reason for the deterioration on the steel market. The general steel demand also declines due to slow growth or even reductions in technology fields like ship building, thermal power plants, infrastructural needs, or even the automotive industry. Nevertheless, environmental and energy-efficient production routes are of primary interest, partly handled by thin strip production processes. TMCP (thermo-mechanical controlled processing) remains a main research field for many applications. Increased demands are expected regarding enhanced strength for light-weight design, improved toughness to ensure safety in case of earthquakes and fires, or improved formability to overcome geometrical limits. New steel grades like bainitic steels, nano-crystalline materials, TWIP-steel or grain-oriented electrical sheet metals have led to advanced quality criteria also for rolling plants. Furthermore, steel has to stay competitive against lightweight metals, CFK, and plastics. Some examples of recent innovative processing optimizations are described requiring not only process monitoring but also model-based simulation and real-time online control. Finally, the article states that new holistic strategies are necessary to overcome future challenges.