Rolling Mill Production Research Articles

A Seq2Seq transformation strategy for generalizing a pre-trained model in anomaly detection of rolling element bearings

The monitoring of the health of Rolling Element Bearings (REBs) in the rolling mill process was recently automated through signal processing and machine learning technologies. However, large data sets are required, and existing methods require precise labels. Moreover, the scarcity of equipment anomalies challenges their practical identification. In addition, machine learning approaches require human resources to manage machine learning models because all REBs in the production line are not identical. Thus, we propose herein a Seq2Seq Transformation Strategy inspired by the accurate performance of such the methods in Natural Language Processing (NLP) and Computer Visioning (CV). Our strategy aims to use an anomaly detection model trained on one signal to detect anomalies in other signals, reducing the need for model management in practical scenarios. Specifically, we considered time series vibration signals collected from the REBs to be analogous to linguistic data, which are sequential and time variant. In essence, our strategy generates synthetic data from a vibration signal represented as the target domain by using a transformer. Subsequently, a model trained by another signal called the source domain is employed to detect the conditions of the target domain. The goal of transformation is to minimize the differences between the distributions of the synthetic and source data. We assumed that the target conditions could be identified from the synthetic data by the source model if the detection model trained on the source domain was precise. Our strategy was experimentally evaluated on six large, unlabeled data sets collected over 1 year from a rolling mill production line in a steel factory. The strategy significantly improved the accuracy of anomaly detection, which had initially been unacceptable when the source model was directly applied to the detection of the target conditions.

Determination of dynamic component reactions in support bearings of rotor saws for cutting hot rolled (message 1)

A distinctive feature of rotary saws is the process of cutting the workpiece, which takes a very short time. For example, a workpiece with a diameter of 200 mm is cut in 0.2 seconds, while traditional designs of sliding and pendulum saws perform this operation in 10-20 seconds or more. This effect is achieved due to the high speeds of feeding the disc to the cut, exceeding traditional modes by 20 or more times. However, due to the specific cutting conditions, weak links were identified in these designs that require further improvement. One of the factors that reduces the reliability of the saw is the insufficient durability of the bearings of the high-speed disk shaft, which perceives the cutting force. Until now, the reliability issues of rotary saw structures remained unresolved. One of the factors that reduces the reliability of the saw is the insufficient durability of the bearings of the high-speed disk shaft, which perceives the cutting forces. Practice shows that the applied methods of calculating the strength of support bearings do not allow taking into account all possible factors that affect the reliability of bearings in the cutting process. First of all, as it turned out, during operation, the saw blade has radial runout, possibly due to an error when cutting the teeth of the blade and the eccentric landing of the blade on the seat when replacing it. For modern rolling mill production, the issue of strength and reliability of rotary saw designs, which are intended for cutting rolled metal, is relevant. The purpose of this work is to determine the precise values of the reaction forces of the support bearings of the disc shaft. As you know, during long-term operation of the object, the place for landing the cutting disc on the faceplate wears out, sometimes there is an error in the hole when making a new disc. Therefore, there is an eccentricity of the center of gravity of the disk. The presence of this eccentricity is taken into account in the work when determining the required forces using D'Alembert's principle of conditional balancing of forces. Due to the fact that the process of cutting with a circular saw is very short-term, the cutting force is considered the impact force. The magnitudes of the reaction forces in the bearings are determined during cutting using the impact dynamics theorems: the momentum theorem and the kinetic momentum change theorem. By projecting the vector formulas of the principle and theorems on the coordinate axis, the systems of algebraic equations are obtained, from which the horizontal and vertical components of the reaction forces in the bearings are determined both in idle mode and during cutting. Due to the fact that the vector of the centrifugal Dalembert force of inertia of the disk changes its direction, the formulas of the reaction forces at different positions of the center of gravity of the disk were obtained. According to the results of the planned numerical analysis of the problem, graphs of the dependences of the horizontal and vertical components of the pressure forces on the bearings can be drawn from: the eccentricity value, the vertical and horizontal components of the cutting forces, the angular velocity and the position of the disk

Research on Strip Profile Control Characteristics of 1500 mm Quintic CVC Mill

Compared with cubic Continuously Variable Crown (CVC), quintic CVC presents integrated control capability of quadratic and quartic crown. In order to take full advantage of quintic CVC and have better comprehensive control of the edge wave, center wave, high order wave and complex wave in practical application, it is necessary to further clarify the complicated profile control characteristics of quintic CVC. In this paper, quintic CVC technology in a 1500 mm continuous hot rolling mill production line has been taken as the research object and use finite element method to study its profile control characteristics. Through finite element simulation, an integrated model of rolls and strip was established to analyze the influence of the shifting, bending force and rolling force on strip profile with different strip widths. Both crown adjustment area and transverse stiffness are gained to study the control capability of quintic CVC. The simulation results show that the positive shifting and positive bending of CVC work roll reduce the quadratic crown and increase the quartic crown, and the controlling effect of shifting on both quadratic and quartic crown is more remarkable than that of bending. The control capability of the crown increases with the increase of strip width. That is, wider strip has a larger crown adjustment area. Meanwhile, there is a strong coupling relationship that the increase of quadratic crown can lead to the decrease of the quartic crown, which is not good for the flexible control of strip profile. With the increase of rolling force, the quadratic crown of strip increases significantly, while the quartic crown does not change obviously. Additionally, the increase of strip width significantly increases the transverse stiffness of mill.

Research on the optimization strategy of lithium battery electrode correction system based on algorithm fusion

In the control system of a lithium battery rolling mill, the correction system was crucial. This was because the correction system had a significant impact on the performance of the lithium battery rolling mill, including high precision and efficient rolling quality. However, the non-linearity of the correction system and the uncertainty of the correction system made it a challenging problem to achieve a high precision correction control. The contribution and innovation of this paper was a genetic fuzzy PID control strategy based on Kalman filter, which was proposed and applied to the control of lithium battery rolling mill correction technology. In order to achieve intelligent control of a high-precision electrode rolling mill correction system, an algorithm fusion control scheme was proposed. Firstly, a novel and detailed correction system model was presented. Next, the initial PID parameters of the correction were optimized by means of a genetic algorithm so that the PID parameters could be adapted to the correction control process and then optimized again by adding an extended Kalman filter. Finally, the lithium battery rolling mill correction control system was validated, tested and commissioned in the field. The results showed that the designed algorithm could meet the working requirements of the lithium battery rolling mill and that it improved the accuracy of the correction system. In the actual lithium battery rolling mill production process, the algorithm was compared with a conventional PID. Compared with the common single algorithm, the fusion algorithm proposed in this paper was a complete set of high precision correction control system algorithm to solve the high precision problem faced by the correction system in the actual lithium battery rolling mill correction system.

Про формування первинної структури та властивостей економнолегованих хромомарганцевих сплавів у литому стані

The purpose of the work is to study the peculiarities of the influence of the chemical composition on the formation of the primary structure and properties of chromium-manganese alloys. Piercing mandrels belong to the replaceable tool of hot deformation, the operational characteristics of which affect the productivity of pipe rolling mills and the quality of finished products. The costs of the hot deformation tool are a component of the cost price of metal products, so the interest in increasing their operational stability is constantly growing. The development of a rational component composition of alloys is based on ideas about the peculiarities of the course of structural and phase transformations during crystallization, heat treatment, as well as under the influence of high temperatures and loads during operation. To develop an effective mode of final heat treatment of wear-resistant products, one should have an idea about the quality of the cast material and its primary structure, in particular by determining the dynamics of changes in indicators, the formation of which is due to liquidation phenomena. The purpose of the work is to study the peculiarities of the influence of the chemical composition on the formation of the primary structure and properties of chromium-manganese alloys. The peculiarities of the formation of the cast structure, phase composition, and properties of economically alloyed chromium-manganese alloys intended for the manufacture of piercing mandrels have been studied. According to the results of tests on frictional wear, it was established that chromium-manganese alloys have higher wear resistance compared to cast iron of the 300Cr32Ni3V and the “nikorin” alloy (36.0–38.0 % Cr; 57.0–59.0 % Ni). According to the results of the X-ray spectral analysis, it was established that in the structure of the experimental alloys, the highest values of the liquidation coefficients are characteristic of Ni, V and Cu. With an increase in the content of C, Mn, Cr, and Ni, the degree of doping of the matrix and carbides increases, which leads to an increase in the wear resistance of the chromium-manganese alloys. The obtained results with a high probability allow us to state that the further development of effective modes of final heat treatment of the proposed chromium-manganese alloys will ensure an increase in the operational stability of the piercing mandrels of pipe rolling mills while simultaneously reducing the material costs for their manufacture.

Reviews in Dynamic Characteristics of Rolling Interface and Vibration Test/Suppression Methods of the Rolling Mill

Background: Rolling mill vibration mechanism is very complex, and people haven't found a satisfactory vibration control method. Rolling interface is one of the vibration sources of the rolling mill system, and its friction and lubrication state has a great impact on the vibration of the rolling mill system. It is necessary to establish an accurate friction model for unsteady lubrication process of roll gap and a nonlinear vibration dynamic model for rolling process. In addition, it is necessary to obtain more direct and real rolling mill vibration characteristics from the measured vibration signals, and then study the vibration suppression method and design the vibration suppression device. Methods: This paper summarizes the friction lubrication characteristics of rolling interface and its influence on rolling mill vibration, as well as the dynamic friction model of rolling interface, the tribological model of unsteady lubrication process of roll gap, the non-linear vibration dynamic model of rolling process, the random and non-stationary dynamic behavior of rolling mill vibration, etc. At the same time, the research status of rolling mill vibration testing technology and vibration suppression methods were summarized. Time-frequency analysis of non-stationary vibration signals was reviewed, such as wavelet transform, Wigner-Ville distribution, empirical mode decomposition, blind source signal extraction, rolling vibration suppression equipment development. Results: The lubrication interface of the roller gap under vibration state presents unsteady dynamic characteristics. The signals generated by the vibration must be analyzed in time and frequency simultaneously. In the aspect of vibration suppression of rolling mill, the calculation of inherent characteristics should be carried out in the design of rolling mill to avoid dynamic defects such as resonance. When designing or upgrading the mill structure, it is necessary to optimize the structure of the work roll bending and roll shifting system, such as designing and developing the automatic adjustment mechanism of the gap between the roller bearing seat and the mill stand, adding floating support device to the drum shaped toothed joint shaft, etc. In terms of rolling technology, rolling vibration can be restrained by improving roll lubrication, reasonably distributing rolling force of each rolling mill, reducing rolling force of vibration prone rolling mill, increasing entrance temperature, reducing rolling inlet tension, reducing strip outlet temperature and reasonably arranging roll diameter. The coupling vibration can also be suppressed by optimizing the hydraulic servo system and the frequency conversion control of the motor. Conclusion: Under the vibration state, the lubrication interface of roll gap presents unsteady dynamic characteristics. The signal generated by vibration must be analyzed by time-frequency distribution. In the aspect of vibration suppression of rolling mill, the calculation of inherent characteristics should be carried out in the design of rolling mill to avoid dynamic defects such as resonance. It is necessary to optimize the structure of work roll bending and roll shifting system when designing or reforming the mill structure. In rolling process, rolling vibration can be restrained by improving roll lubrication, reasonably distributing rolling force of each rolling mill, increasing billet temperature, reasonably arranging roll diameter and reducing rolling inlet tension. Through the optimization of the hydraulic servo system and the frequency conversion control of the motor, the coupling vibration can be suppressed. The paper has important reference significance for vibration suppression of continuous rolling mill and efficient production of high quality strip products.

Investigation of Self-Oscillations and the Development of a Procedure of Stabilization of the Process in a Continuous Mill for Strip Cold Rolling

We study the problem of operation of sheet rolling mills under the conditions of nonstationary technology, the stochasticity of the parameters in the presence of negative self-oscillation vibration processes associated with the “chatter” phenomenon. We determine the parameters of stability of the process of sheet rolling, reveal the main causes of the chatter phenomenon, and describe the mechanism of their initiation. We also propose a procedure for the identification of this phenomenon by continuous statistical processing of the parameters of rolling process. As a result of the performed investigations, we developed a method aimed at the adjustment of the technology, which excludes vibration and enables us to enhance the productivity of rolling mills by means of increasing the average speed of rolling.

Automatic monitoring of steel strip positioning error based on semantic segmentation

The misalignment of steel strips in relation to the roller table centerline still is an impairment for the rolling mill production lines. Nowadays, the strip position correction remains largely in the purview of human analysis, in which the strip steering is traditionally a semi-manual operation. Automating the alignment process could reduce the maintenance costs, damage to the plant, and prevent material losses. The first step into the automatization is to determine the strip position and its referred error. This study presents a method that employs semantic segmentation based on convolution neural networks to estimate steel strips positioning error from images of the process. Additionally, the system mitigates the influences of mechanical vibration on the images. The system performance was assessed by standard semantic segmentation evaluation metrics and in comparison with the dataset ground truth. The results showed that 97% of the estimated positioning errors are within a 2-pixel margin. The method demonstrated to be a robust real-time solution as the networks were trained from a set of low-resolution images acquired in a complex environment.

Assessment of the impact on the health of the population of emissions from rolling production of a metallurgical plant

Introduction.Th e development of the metallurgical industry in Novokuznetsk, Kemerovo region, has led to a diffi cult environmental situation. Determining the relationship between exposure to atmospheric emissions and the health of the population based on the risk assessment methodology is an urgent hygiene issue.The aim of the studyis to assess the risk of health problems from emissions from rolling production of a metallurgical plant.Materials and methods. We used data from the volume of maximum permissible emissions of the enterprise. Calculations of maximum single and average annual concentrations of pollutants were carried out using the program “ECOcenter-Standard”. Public health risks were calculated and compared with acceptable values. Th e work also determined the values of risk levels taking into account background concentrations.Results.Priority pollutants were identifi ed: diiron trioxide, nitrogen dioxide, nitrogen oxide, sulfur dioxide, carbon monoxide, benz(a)pyrene. Th e maximum one-time and average annual concentrations of substances at the selected calculation points were determined, and the maximum permissible concentration of diiron trioxide was found to be exceeded. Immediate action risk levels are zero. The highest risk levels of chronic intoxication, expressed as a percentage of a unit, are observed from exposure to diiron trioxide (0.004-0.043) and nitrogen dioxide (0.001-0.012). The maximum total level of risks of chronic intoxication (0.012) is observed at the point of exposure to concentrations #3 from the infl uence of nitrogen dioxide, which is due to the close location of pollution sources. The carcinogenic risk from exposure to benz(a)pyrene ranges from 1×10-8 to 9×10-8 (as a fraction of a unit). The combined values of carcinogenic risk and immediate action risk are below the acceptable risk level. In seven points of exposure to concentrations, the total risk of chronic intoxication exceeds the acceptable level by 1.10-3.45 times.The greatest risk of immediate action, taking into account background concentrations, is observed from the action of carbon monoxide and benz(a)pyrene. Th e carcinogenic risk exceeds the acceptable level by 6-12 times. The risk of chronic intoxication, taking into account the background, exceeds an acceptable level. Th e highest total risk levels are typical for the Kuznetsky district of Novokuznetsk. Conclusions. Atmospheric emissions fr om rolling mill production contribute to air pollution in the city, increasing the risk of chronic intoxication.

System dynamics of a pipe pilger CRM working stand

Efficiency of the pilger cold rolling of pipes process realization can be increased both by perfection of the rolling process and by a selection of rational parameters of the base technological equipment and the mills functioning regimes. Particular attention should be paid to the increase of reliability of functioning, increase of high-speed and productivity of pipe cold rolling mills (CRMs). Results of the system analysis of dynamics of pipe CRM working stand of various designs presented. A calculation algorithm elaborated and differential equations of the pipe CRM working stand obtained. Pictures of dynamic motions for selected pipe CRM working stand obtained. The analysis of theoretical studies showed, that for stabilization of the stand base elements it is necessary to increase the rigidity of the working stand correspondent elements. It was shown, that the stand rigidity increase reached by arrangement longitudinal bridge of variable thickness, connecting the internal and external structure’ casing. An optimal design roller actuator elaborated. Implementation of the actuator will enable to accomplish the technological process more effectively, since the unit’ elements can adopt all possible inaccuracy of the working stand manufacturing and assembling, as well as housing post deformation. It was ascertained, that the roller actuator of optimal design, above all, plays a role of an emergency gear of the pipe CRM working stand. The studies revealed that increase of productivity and quality of the manufactured products reached mainly by application of the working stand of rational design at the pipe CRM. The industrial running the modified variant of working stand design during eight years to roll hard-deformed steels and alloys confirm its high efficiency at production of precision high quality pipes.

Improving the Performance of the Annular Furnace at PAO ChTPZ

Abstract—The productivity of rolling and pipe-rolling mills and the product quality may be improved by heating the metal billet in furnaces with minimum oxidation and decarburization. That is possible in annular furnaces, which are widely used in the rolling of pipe and railroad wheels. High-quality heating permits the creation of metal structure with specified thermophysical and operational properties, as well as the plasticity required for subsequent machining. In the present work, the operation of an annular furnace used to heat pipe blanks before rolling at PAO Chelyabinskii Trubokatnyi Zavod (ChTPZ) is analyzed. Thermal problems are considered: in particular, the high fuel consumption in heating blanks and high external temperatures of the walls and roof; the low rate of blank heating; and the serious leakage of air into the furnace’s working space. In addition, a defect of the gas-burner design is that the gas supply cannot be regulated, despite the wide load range (including periodic shutdown). Finally, practically no use is made of the thermal energy in the exhaust gases. In the analysis of these problems, the heating of the metal is calculated, and the thermal balance of the annular furnace is formulated. The analysis reveals factors that decrease the energy efficiency of the existing furnace design. Measures are proposed for furnace modernization so as to decrease the fuel productivity and increase the productivity: for example, the use of fiber refractories; regenerator burners; and barriers that are not water-cooled. To assess the effectiveness of these measures, we formulate the thermal balance of the redesigned annular furnace and analyze its thermal operation. The proposed measures are expected to provide significant economic benefit and to improve the heating of the metal, with decrease in fuel consumption and increase in productivity. In particular, after reconstruction, increase in the furnace’s total efficiency (by 18.1%) and thermal efficiency (by 31.0%) is expected, as well as decrease in fuel consumption by 48.3 kg CF/t.

Analisis Kadar Glukosa Darah pada Pekerja Shift Pagi dan Shift Malam di PT. X Sidoarjo

Shift work, besides has several advantages also has a negative effects. The negatives effects are including physiological, social and performance effects. The physiological effects that arise among them such as blood glucose metabolism disorders which these risk may also occur to the shift workers. This study was conducted in PT. X at september 2015 aims to determine the pattern of PT. X shift working systems and also knows the difference between random blood glucose on morning shift and night shift workers at PT .X. This was a descriptive crossectional research. Sample in this study were using the total population of shift workers in Rolling Mill production unit who measured their random blood glucose levels while working on morning shift and the night shift and was not suffering from diabetes mellitus with total 26 respondents. The result showed that PT. X is applied weekly slow rotation and backward rotation pattern (night – day – morning) of shift working system.The difference between random blood glucose and blood pressure levels of the most respondents showed a higher levels while working on the night shift than morning shift. Based on the research, PT. X should apply a quick rotation and forward rotation pattern (morning – day – night) of shift working system and giving a 24 hours time rest at the end of night shift schedule. And they should held the routine exercise activity once a week at the plant and giving the explanation about the negative effects of the shift work to the related workers.

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.

Dynamic control of lubrication characteristics in high speed tandem cold rolling

Friction in continuous process varies irregularly depending on the material conditions, lubrication conditions and industrial environment. While control of friction in industrial processes is being improved empirically by trial and error, friction control within the optimum range for each process is essential. The recently proposed hybrid lubrication system is helpful to achieve higher rolling speeds and more stable rolling in order to improve the productivity of tandem cold rolling mills. In this paper, an intelligent lubrication control system for preventing chatter was proposed. In a basic study, the vibration stability of the rolling mill was investigated by using a self-excited vibration model. For stable high speed cold rolling, it is important to optimize the balance of the friction coefficients in a multi-stand rolling mill. Based on this idea, a new actuator for controlling the friction coefficient balance was proposed. Lubrication characteristic control by the flow quantity feedback in hybrid lubrication system was evaluated by a dynamic rolling simulation based on MATLAB/Simulink and demonstration experiments in actual rolling mill. Feedback control of the plate-out oil film from a hybrid lubrication system could be achieved as an actuator for balancing the friction coefficients between the final stand and preceding stand. The results of this research suggest that the hybrid lubrication system with the proposed actuator is possible to prevent chatter efficiently in high speed cold rolling region.

Estimation model of plate-out oil film in high-speed tandem cold rolling

Out of all the variables associated with rolling, none is more important than friction in the roll bite. Friction in rolling, as in many other mechanical processes can be a best friend or a fatal enemy, and its control within an optimum range for each process is essential. The friction is the interconnected phenomena; material, lubrication and heat transfer at the contact surface in cold rolling. Moreover, the friction behavior in industrial environment is highly unclear. It is important to break down many tribological attributes in actual cold rolling into simple laboratory tests. The proposed hybrid lubrication system is helpful to achieve higher rolling speed and more stable rolling for improving the productivity of tandem cold rolling mills. In this paper, an estimation model of the oil film on the strip by the proposed system at the exit section of tandem cold rolling was proposed based on a combination of laboratory tests and a starvation model. The results of this research suggest that it is possible to clarify the lubrication characteristics in tandem cold rolling by using the proposed model.

CAPACITY OF THE INTERSTAND COOLING UNIT IN HOT ROLLING PROCESS

The aim of the paper was to improve the economy of rolling mill production and to extend the control range of cooling capacity of the accelerated cooling unit by choosing the optimal dimensions of the cooling chamber. The object of research was the interstand cooling unite for accelerated cooling of the hot-rolled products of round section in the line of continuous rolling mill in order to reduce the machine time rolling or even eliminate completely the requirement for heat treatment of the hot-rolled products in heat-treatment furnaces. The influence of the design parameters of the cooling chamber on the expanding the control range, retaining a high cooling capacity of the chamber, was investigated by the numerical model based on the finite difference method. The diagrams presented in the paper allow determining the diameters of the cooling chamber, which provide a wide control range of the chamber cooling capacity and minimization of energy consumption of the electric water pump.

High-speed rolling by hybrid-lubrication system in tandem cold rolling mills

Lubrication is one of the most important factors for improving the productivity of tandem cold rolling mills, as it is possible to increase the rolling speed of thin gauge steel strips and prevent chatter when rolling materials with high deformation resistance. In this study, a new hybrid lubrication system is proposed and its effectiveness is clarified. The system is based on a lubricant recirculation system combined with a system for flexible lubrication control. The key to realizing the new lubricant system is control of plate-out oil film formation on the strip surface under high-speed rolling conditions. The plate-out oil film formation of emulsions is investigated, and the conditions for achieving a sufficient plate-out oil film are clarified. The time-dependent property, oil droplet size, and emulsion concentration are found to have significant effects on plate-out behavior. In addition, the conditions for practical application of hybrid lubrication systems are discussed from the viewpoint of realizing effective plate-out control. A new hybrid lubrication system was investigated, and it successfully enabled flexible controllability of lubrication conditions and achieved the high-speed stable rolling, while maintaining an oil consumption rate equal to that of recirculation systems.

冷間圧延における潤滑状態の制御技術

Lubrication is one of the most important factors for improving the productivity of tandem cold rolling mills, as improved lubricity makes it possible to increase the rolling speed of thin steel strips and prevent chatter when rolling materials with high deformation resistance. A new hybrid lubrication system is proposed and its effectiveness is clarified. The system is based on a coolant recirculation system in combination with an added system for flexible lubrication control. The key to realizing stable coolant system operation is a control technology for plate-out oil film formation on strips under high-speed-rolling conditions. The new technology has been applied to the fabrication of a production tandem cold-rolling mill for thin steel strips. It successfully enables flexible controllability of lubrication conditions and achieves high-speed stable rolling, while maintaining an oil consumption rate equivalent to that of recirculation systems.

PVD coatings for mill rolls for cold rolling of high carbon steel strips—Laboratory tests

Increasing the productivity of rolling mills requires improving surface properties of roll surface and prolonging roll life. The properties of interest are anti-adhesion to avoid catastrophic adhesive transfer, and wear resistance. Hard Cr coatings provides such properties for Al and carbon steel rolling, but should be replaced in the long run due to health/environmental issues. Physical Vapor Deposition (PVD) and Plasma-Enhanced Chemical Vapor Deposition (PECVD) of ceramic coatings are promising substitutes. In the context of high carbon steel strip rolling, TiN, TiBN, and CrN are tested here in terms of adhesive properties under large sliding conditions (plate-on-ring test) at increasing load. They are compared with a naked High Speed Steel (HSS) surface and a hard chromium coating. A 3-stage evolution is found as load increases, the last stage being characterized by massive adhesive transfer (severe wear) and high, irregular friction. TiN is shown to perform poorly under these conditions and does not bring an alternative solution to HSS steel. On the contrary, TiBN and CrN provide anti-adhesion protection up to the maximum load of the test, like Cr.

Data-Driven Residual-Based Fault Detection for Condition Monitoring in Rolling Mills

We propose a residual-based approach for fault detection in rolling mills which is based on data-driven soft computing techniques. The basic idea is to transform original measurement signals into a feature space by (i) identifying multi-dimensional relationships in the system, (ii) representing the nominal fault-free case, and (iii) analyzing residuals with incremental/decremental statistical techniques. Model identification and fault detection are conducted in a completely unsupervised manner, that is, solely based on the data streams recorded online. Thus, neither annotated samples nor fault patterns/models, which are often very time-intensive and costly to obtain, must be available a priori. We use purely linear models, a new genetic variant of Box-Cox models (termed Genetic Box-Cox) that consider weak non-linearities, and Takagi-Sugeno fuzzy models, which are able to express more complex non-linearities, trained with an extended version of SparseFIS. Using three typical scenarios from rolling mill production, we compare our method to state-of-the-art approaches that are based on principal components analysis and multi scale principal components analysis. The results show that our method outperforms these state-of-the-art approaches.