Hot Rolling Mill Research Articles

Selection of parameters of high-speed thermodeformation of Cr–Ni–Mo steel processing on the basis of imitation modeling

The temperature of the end of finishing stage, cooling rate and coil winding temperature are structure-sensitive parameters for bainite-grade steels in the production of plate less than 10 mm thick. Simulation modeling of high-speed thermo-deformation processing of Cr–Ni–Mo bainitic steel samples has been carried out in order to select the most rational technological modes in continuous hot rolling mills. The influence of strain rate and temperature as well as niobium and vanadium microalloying additives on phase transformations has been investigated.

Slab assignment to non-identical reheat furnaces running in parallel mode

This article analyses a slab assignment problem for non-identical reheat furnaces in the steelmaking industry. We tackle the problem of assigning slabs to different types of reheat furnaces, a walking beam and a pusher type furnace. Furthermore, we need to determine the feed-in as well as the residence time for each slab. The aim is to (i) reduce the energy consumption, (ii) increase the production rate and (iii) the heating quality of the slabs which depends on the assigned furnace and to what extent the slabs are overheated. Moreover, the subsequent production stage (Hot Rolling Mill), needs to be synchronized with the furnaces which is essential for a smooth production. We specify the problem as a mixed integer optimization formulation that is solved with iterative parameter adjustment. Rapid convergence leads to a novel two-phase solution method that yields furnace schedules that are optimal for the adjusted parameter values in reasonable time. The results show that our proposed method performs better than an industry benchmark by increasing the production rate and increasing the reheating quality. Furthermore, the new generic problem formulation allows using standard software and can be applied to identical or non-identical furnaces highlighting its broad applicability across steel-making companies.

An integrated approach to analysis and assessment of condition parameters of the surface layer of backup roll bodies of a continuous broad-strip hot rolling mill

An integrated approach to analysis and assessment of condition parameters of the surface layer of backup roll bodies of a continuous broad-strip hot rolling mill

Monitoring and adjustments of combustion parameters in reheating furnaces using a digital tool

Improving the energy efficiency of a reheating furnace is not a simple task because it involves a large number of parameters that, most of the time, are connected in a complex way. To be feasible, the evaluation of such a vast number of variables must be supported by digital tools that are embedded with artificial intelligence. The SMS group has developed a digital tool that effectively supports operators and engineers in enhancing energy efficiency within the reheating furnaces of hot rolling mills. This paper presents a quick study case of the use of Viridis Performance, an application of Viridis Energy & Sustainability Suite, in the analysis and correction of the deviations in the air-gas ratio of a reheating furnace. In this study, a production period of 8 hours was evaluated, during which the air-gas ratio presented a significant deviation. Analysis showed that the probable cause of the deviation was a production stoppage where the furnace control was set to manual mode. A reduction potential of 0.26 Gcal/h and a 13 kg/h decrease in CO2 emissions were identified. Viridis Performance would support the process by guiding the decisions of the operator in a way that energy losses would be avoided or minimized. The potential economic savings were also quantified. This task is performed in the system by Viridis Moneybox, which is another application of Viridis Energy & Sustainability Suite. The results showed potential savings of 13 US $/h. In addition to the gains and savings outlined in this study, the utilization of Viridis Performance encompasses numerous other advantages, such as enhanced operational standardization and improved process capability, to name just a few.

Research on Multi-System Coupling Vibration of a Hot Tandem Mill

Vibration in hot tandem rolling mills has been a problem in the iron and steel industry mainly due to its unpredictability. In this work, vibration data of the second finishing mill (F2) stand of a hot tandem rolling mill are collected and analyzed, and a mathematical model based on the coupling of a non-uniform deformation process, mill structure and hydraulic control system is constructed. The influence of different inlet thickness fluctuation forms, structural parameters and control parameters on the vibration behavior is analyzed. It is concluded that the low-frequency thickness fluctuation with additional skewness can cause the resonance of each subsystem of the rolling mill. The deviation angle of the roll system influences the vibration harmonic output of the rolling mill under a single low-frequency thickness fluctuation excitation. The compensation parameter in the thickness control system affects the natural frequency of the vertical system.

Power Factor Modelling and Prediction at the Hot Rolling Mills’ Power Supply Using Machine Learning Algorithms

The power supply is crucial in the present day due to the negative impacts of poor power quality on the electric grid. In this research, we employed deep learning methods to investigate the power factor, which is a significant indicator of power quality. A multi-step forecast was developed for the power factor in the power supply installation of a hot rolling mill, extending beyond the horizontal line. This was conducted using data obtained from the respective electrical supply system. The forecast was developed via hybrid RNN (recurrent neural networks) incorporating LSTM (long short-term memory) and GRU (gated recurrent unit) layers. This research utilized hybrid recurrent neural network designs with deep learning methods to build several power factor models. These layers have advantages for time series forecasting. After conducting time series forecasting, qualitative indicators of the prediction were identified, including the sMAPE (Symmetric Mean Absolute Percentage Error) and regression coefficient. In this paper, the authors examined the quality of applied models and forecasts utilizing these indicators, both in the short term and long term.

Float-stacked graphene–PMMA laminate

Semi-infinite single-atom-thick graphene is an ideal reinforcing material that can simultaneously improve the mechanical, electrical, and thermal properties of matrix. Here, we present a float-stacking strategy to accurately align the monolayer graphene reinforcement in polymer matrix. We float graphene-poly(methylmethacrylate) (PMMA) membrane (GPM) at the water–air interface, and wind-up layer-by-layer by roller. During the stacking process, the inherent water meniscus continuously induces web tension of the GPM, suppressing wrinkle and folding generation. Moreover, rolling-up and hot-rolling mill process above the glass transition temperature of PMMA induces conformal contact between each layer. This allows for pre-tension of the composite, maximizing its reinforcing efficiency. The number and spacing of the embedded graphene fillers are precisely controlled. Notably, we accurately align 100 layers of monolayer graphene in a PMMA matrix with the same intervals to achieve a specific strength of about 118.5 MPa g−1 cm3, which is higher than that of lightweight Al alloy, and a thermal conductivity of about 4.00 W m−1 K−1, which is increased by about 2,000 %, compared to the PMMA film.

Researches regarding power quality at the hot rolling mills’ power supply

The study described in the paper was carried out through measurements taken at a feed station in a hot rolling line. The aforementioned measures are appropriate for the purpose of analyzing power quality. The measurements were taken using a three-phase power quality analyzer. Measurements were taken for voltage and current values, as well as for active, reactive, and apparent powers. The analysis of the measurements taken indicates that the power quality is affected by the nonlinearity of the load. As a consequence, the level of reactive power becomes higher, leading to a reduced power factor.

Improving the Methodology for Calculating the Finishing Group Power of a Continuous Wide-Strip Hot Rolling Mill

Improving the Methodology for Calculating the Finishing Group Power of a Continuous Wide-Strip Hot Rolling Mill

Numerical Simulation Research on the Temperature Field and Hot Roll Crown Model of Hot Continuous Rolling Mills

Addressing the challenge of roll loss and strip deformation arising from the lack of precise prediction of the roll temperature field in hot tandem rolling mills, this study employs numerical analysis via the finite difference method. Based on the roll temperature field and hot roll crown model, an intelligent support cooling control system for the roll cooling water of hot rolls is established. This system comprehensively considers the direct impact of specific parameters on the roll temperature field in the intricate context of cooling water dynamics. The study focuses on the cyclic superposition effect of rolling coil quantities on the roll temperature field and the resulting hot roll shape, and theoretical calculations along with simulation analyses were conducted using finite element software. Through the integration of field-measured values, the study achieves accurate predictions of the temperature field and hot roll profile for both work rolls and backup rolls.

Power Quality Analysis and Improvements in a Hot Rolling Mill using a STATCOM

This paper presents an analysis of the electric power flows in a hot rolling mill plant using a power quality analyzer and developing simulation models with Matlab Simulink. The model inputs have been taken from process data by the process computer of the plant. A STATCOM with a control strategy based on the d-q coordinates is used as solution to improve the reactive compensation as well as to minimize the voltage fluctuations and sags effect. The overall electric model has been simulated with the STATCOM to check the improvement in the voltage stability and the consumption.

PROPANE-BUTANE SUPPLY FOR COKE OVEN AND BLAST FURNACE GAS ENRICHMENT IN REHEATING FURNACES

This article proposes organizational and technical measures to reduce energy consumption of re-heating furnacessection of hot rolling mill 1700 in hot rolling shop No.1 of “ArcelorMittal Temirtau” JSC, such as fuel combustionquality management, performed and presented calculation of energy consumption per unit of production. The industrial experiment was performed there. As it is known, one of the features of re-heating furnaces is the fact that the minimum specific fuel consumption takes place when burning it with the maximum possible pyrometric effect. To solve the research tasks, a fundamentally new 3D model of combustion products motion with the possibility of parameters correction to calculate and optimize the energy-efficient operation of the furnace was applied. Experimental data were obtained on high-precision stationary and portable equipment, metering devices passed state inspection, which excludes the unreliability of the data obtained.

Study of wear on surface of work rolls barrels of continuous stands of wide strip hot rolling mill

The results of the patterns of wear on the surface of the work roll barrel of the quarto stand of a hot rolling mill are presented. It is established that wear will be mainly determined by the hardness of the work roll barrel surface, the rolling force in the deformation zone, the amount of rolled material produced on the roll, as well as the average diameter of the roll barrel. The greatest effect on wear as the amount of rolled stock increases is the rolling force, as well as the hardness of the barrel surface. The proposed technique makes it possible to predict the uneven wear of the surface of the roll barrel along its length. Taking this unevenness into account can be useful for controlling the profile of the strip and its shape.

Prediction of the “Screw-nut” gear life

A method has been developed for predicting the service life of a screw pair nut with a large thrust thread, which is based on the energy theory of wear. Based on the results of finite element modeling using the DEFORM-3D software package, the dependence of the change in normal pressures on the contact surface of the nut with the screw along the height of the thread projection was established. Using the SMTs-2 friction machine, a series of experiments was carried out and the coefficient of friction and the energy index of wear intensity were determined for bronze of the brand BrA9Zh3L, used in the manufacture of nuts for screw mechanisms with coarse threads. The calculation of the service life of the nut of the pressure device of the rolling stand of the hot rolling mill 2000 has been performed. The limit value of the number of revolutions of the screw is established, the excess of which leads to critical wear and destruction of the threads.

Improving Hot Rolling Mill Operations through Lean Manufacturing and Optimization Techniques

Improving Hot Rolling Mill Operations through Lean Manufacturing and Optimization Techniques

Effect of Latent Heat by Phase Transformation on the Thermal Behavior of Steel Billet during Heating.

The effect of latent heat via phase transformation on the thermal behavior of a billet was investigated during the heating process. The latent heat of the billet strongly affected the temperature distribution of the billet during heating, although the heating rate of the billet was not high during the process. The temperature profile of the center region of the steel billet with latent heat had a strong flat shape compared with the other regions, as the heat supply to the center region was limited during the heating process owing to the finite thermal conductivity and mass effect of the billet. The latent heat by phase transformation typically occurred in the middle stage of heating, and the latent heat increased the temperature deviation of the billet during heating owing to the delay in the temperature rise at the center region of the billet. During the phase transformation of carbon steels during heating, the gas temperature needs to be low to reduce the temperature deviation or thermal stress of the billet. Industrial hot rolling mills are required to consider the latent heat by phase transformation of the billet to properly design the heating pattern for the billet. The heating pattern in the reheating furnace should be varied with the materials to obtain a high heating quality for the billet.

Research on the Online Monitoring of the Service Status of Hot-Rolling Mill Work Rolls and Online Decision-Making Method for Active Remanufacturing

Research on the Online Monitoring of the Service Status of Hot-Rolling Mill Work Rolls and Online Decision-Making Method for Active Remanufacturing

Decarbonization Pathways, Strategies, and Use Cases to Achieve Net-Zero CO2 Emissions in the Steelmaking Industry

The steelmaking industry is responsible for 7% of global CO2 emissions, making decarbonization a significant challenge. This review provides a comprehensive analysis of current steel-production processes, assessing their environmental impact in terms of CO2 emissions at a global level. Limitations of the current pathways are outlined by using objective criteria and a detailed review of the relevant literature. Decarbonization strategies are rigorously evaluated across various scenarios, emphasizing technology feasibility. Focusing on three pivotal areas—scrap utilization, hydrogen integration, and electricity consumption—in-depth assessments are provided, backed by notable contributions from both industrial and scientific fields. The intricate interplay of technical, economic, and regulatory considerations substantially affects CO2 emissions, particularly considering the EU Emissions Trading System. Leading steel producers have established challenging targets for achieving carbon neutrality, requiring a thorough evaluation of industry practices. This paper emphasizes tactics to be employed within short-, medium-, and long-term periods. This article explores two distinct case studies: One involves a hot rolling mill that utilizes advanced energy techniques and uses H2 for the reheating furnace, resulting in a reduction of 229 kt CO2-eq per year. The second case examines DRI production incorporating H2 and achieves over 90% CO2 reduction per ton of DRI.

Analysis of the roll imprint on the cross-sectional area of hot rolled wire rod by frequency spectroscopy

This work presents an approach for analysing the sensor data of an eddy-current based cross-sectional area measurement for hot rod and wire steel in an innovative manner and for approximating the influence on the forward slip by longitudinal tensile forces between the mill stands. The method is based on frequency spectroscopy of the cross-sectional area of the rolled stock. The measurement data of three sensors already implemented in two hot rolling mills is used in order to obtain information out of the roll imprint on the cross-sectional area. Since measurement data from two measuring sites and from three sensors are evaluated, this allows statements to be made about the reliability and reproducibility of the measurement and shows that the method can be used for different rolling blocks such as 3-roll and 2-roll blocks. In addition, a mathematical model is presented which allows conclusions to be drawn about possible causes for certain characteristics in the measured frequency spectrum of the cross-sectional area.

Optimizing steel coil production schedules under continuous casting and hot rolling

In continuous steel casting operations, heats of molten steel are alloyed and refined in ladles, continuously cast and cut into slabs, and hot-rolled into coils. We present a mixed-integer program that produces a daily casting schedule and that is solved using state-of-the-art software for a 100% direct-charge steel mill; two casters concurrently produce slabs, which are rolled into coils at a single hot rolling mill. This model minimizes penalties incurred by violating plant best practices while strictly adhering to safety and logical constraints to manage risk associated with manufacturing incidents. An efficient formulation, combined with variable reduction and cutting planes, expedites solutions for small instances containing hundreds of variables and thousands of constraints by factors of at least two or three (and sometimes even 100); instances an order of magnitude larger along both problem dimensions suggest solutions that reduce costs incurred using plant best practices by as much as 40%.