Continuous Rolling Research Articles

Study on the transient wheel-rail rolling contact behaviour and key structural parameters of the fixed frog on tram turnout

Trains passing through the turnout experience high-frequency impacts and complex contact behaviour, increasing the likelihood of accidents. To reduce the probability of derailment, the tram turnout fixed frog is improved by optimising the depth of the flange groove to ensure a continuous rolling contact surface. This paper adopts the explicit FE method to analyze the variation pattern of the wheel-rail contact posture during tram passage, investigate the damage mechanism of this new type of structure, and explore the effects of flange groove depth and slope on the performance of vehicles passing through the turnout. The research results show that when the flange is loaded, the contact area has an irregular shape and the flange groove is subject to heavy abrasion under high stress and creep conditions. The service performance of the frog structure can be improved by reducing the flange groove slope. The results provide a theoretical basis for the maintenance and optimal design of the fixed frog.

DNA Reaction Network Central Controller for Dynamic Spatiotemporal Logical Assembly and Its Application for Rational Design of Fluorometric/Electrical Biosensing.

This work introduces a fluorometric/electrical dual-biosensing logic system based on a DNA reaction network (DRN). This system was used to spatiotemporally modulate the kinetic behavior of DNA nanostructures. The system, acting as a programmable and modulative central controller introduced to implement, enabled the monitoring of the target gliotoxin. The DRN encompasses multiple pathways and provides a potential mechanistic way to develop dynamic networks that can evolve under directional controllable conditions. We demonstrated the implementation of a DRN to control the assembly and disassembly of a DNA conveyor belt. By exposing the responsive switches of the DNA conveyor belt, the DRN activates the operation of fluorescent DNA-driving axes based on the aggregation-induced emission effect, enabling signal generation and collection through continuous rolling on the surface of the DNA conveyor belt. The biosensor was employed to monitor gliotoxin, and under optimal conditions, dual-signal detection was achieved at 1.14 × 10-7 and 2.45 × 10-7 μg·mL-1. The biosensor was integrated with a handheld electrochemical workstation, which enabled the successful monitoring of gliotoxin. This strategy enables self-tuning control and the multilayer hierarchical assembly of kinetic behaviors and is applicable to diverse fields such as biometric systems, medical diagnosis, and logic computing.

Possibilities for improvement of technology and equipment for continuous hot rolling of steel strips

Possibilities for improvement of technology and equipment for continuous hot rolling of steel strips

Исследование распределения нормальных контактных напряжений в очагах деформации при горячей прокатке полос из конструкционных низколегированных сталей для повышения стойкости рабочих валков

Introduction. During the operation of the working rolls of the finishing groups of continuous wide-strip hot rolling mills, normal contact stresses have a decisive influence on its resistance and strength, especially when rolling a range of low-alloy structural steels with a minimum thickness range of 5.5–2.0 mm, which does not correspond to the passport characteristics of such mills. The subject of the study. Previously performed studies of the stress-strain state of the rolled strip in the deformation zones make it possible to estimate the level of normal contact stresses acting on the working rolls during hot rolling of strips of low-carbon steels. The paper discusses the results of the study of the stressed state of strips of low-alloy structural steels in contact with rolls, taking into account the features of the chemical composition of the metal and changes in its elastic properties during deformation at hot rolling temperatures. The results obtained are applicable to the evaluation of the contact strength of the finishing rolls of the rolling mill. The purpose of the work is to investigate the distribution of normal contact stresses in the deformation zones during hot rolling of strips of low-alloy structural steels to ensure high resistance of the working rolls. Material and methods. The study is based on the elastic-plastic model and equations for calculating normal contact stresses for each section of the deformation zone. The specificity of variation of Young's modulus (modulus of elasticity) of low-alloyed structural steels in accordance with certain hot rolling temperatures is studied in detail, and the contact strength of high-chromium cast iron work rolls is evaluated. Results and discussion. A reliable regression equation is obtained for determining the values of the Young’s modulus of the rolled strip as a function of changing hot rolling temperatures. The results of a numerical experiment are presented in the form of calculating the maximum normal contact stresses using the elastic-plastic model of the deformation zone and assessing the contact strength of the work rolls based on actual rolling conditions on an operating mill. New improved technological modes of hot rolling of low-alloy structural steels (0.1 C-Cr-Si-Ni-Cu, 0.18 C-Cr-Mn-Ti and 0.14 C-2 Mn-N-V) are proposed, which make it possible to reduce the maximum contact stresses and increase the resistance of the working rolls.

PRELIMINARY ASSESSMENT OF THE POSSIBILITY OF DOUBLE-STRAND ROLLING AND SEPARATION OF REBAR WITH A DIAMETER OF 22 MM ON A 400/200 OF PJSC KAMET-STAL»

This paper presents proposals for the implementation of a new rolling-separation technology at Mill 400/200 of PJSC “KAMET-STAL” based on the results of mathematical modeling in the finite element program QForm. As part of this work, it is proposed to introduce a new variant of the rolling-splitting technology for rebar with a diameter of 22 mm. According to the proposal, rolled products in stands from 3H to 18H are manufactured in calibers and with settings that correspond to the calibration table for rolling rebars with a nominal diameter of 20 mm. According to this scheme, a double profile is formed in the 17H stand for cutting, and in the 18H stand, the billet is cut longitudinally into two halves with a diameter of 31 mm each. Further along the rolling process, an oval caliber of factory marking 8336 is installed in stand 19H to produce rebars with a nominal diameter of 22 mm (according to the current calibration table for rebars with a nominal diameter of 22 mm, the caliber of stand 15H). Rolls with a round caliber 8345 are installed in the 20H stand (according to the current calibration table for rebars with a nominal diameter of 22 mm – the caliber ofstand 16H). The final production of rebar with a nominal diameter of 22 mm is carried out in two passes in a high-speed 200/4 slitting line. To check the technical feasibility of rolling-separation of rebar profile with a nominal diameter of 22 mm according to the new scheme, the calculation of the deformed state of continuous rolling in the environment for modeling volumetric deformation problems of QForm UK version 10.2.1 was carried out. The model has a number of technical simplifications: all the equipment of the technological line is not taken into account and the distance between the stands is reduced. Simplifications do not reduce the accuracy of the calculation results. Calculations of the deformed state during hot rolling of steel rebar profile with a nominal diameter of 22 mm after separation were performed. The simulation results confirm the possibility of implementing the developed new production technology of rebar profile with a nominal diameter of 22 mm. Calculations showed that the new technology will make it possible to increase the state's productivity during the production of rebar profile with a nominal diameter of 22 mm by 28...29% compared to single thread rolling.

INFLUENCE OF DIFFERENT FACTORS ON THE STABILITY BY ROLLING PROCESS IN THE WIRE BLOCK

One of the leading trends in the development of modern metallurgical manufacturing is the improvement of wire rod production using wire blocks. For existing continuous rolling mills, it is important to maximize the use of equipment capabilities both to improve the quality of products and to reduce the loss of metal and other resources for the adjustment and realize of technological modes at production. Effective technical solutions require scientific justification based on research results. To assess the boundary conditions of the stable rolling process, the average integral of the longitudinal forces at the plastically deformed metal is used. In physical terms, the vector of this force, which opposes the movement of the metal, cannot be directed along the motion of the sample, so the values of the force itself cannot be positive. The assessment of the longitudinal stability of the strip in the rolls (the possibility of a stable rolling process) is as follows: the process is implemented at negative values of the force value, zero value is the limit, at positive values the process is impossible. Analysis of the deformation process in the wire block of rolling mill 200 proved that the specific stresses in the stands should be insignificant because the resource of the forces that draw the metal into the rolls is limited. A more significant influence on the longitudinal stability of the process is the back tension. To ensure the stability of the process, especially in the first passes, the grip angle must be close in value to the coefficient of friction. With an increase in the coefficient of friction, the rolling of wire rod in the wire block becomes more stable. The results of the research show that in the case of external actions on the object, it is theoretically possible to find the limits of self-regulation for the rolling process in a wire block.Whenimplemented, thetechnique makes it possible to assess the limits of self-regulation not only by changes in the size of the workpiece, but by the amount of gauges wear in the rolls, in accordance with changes in friction conditions, temperature of the strip and other parameters.

Study on vertical-torsional chatter under asymmetric conditions in tandem cold rolling

The vibrations generated by the rolling mills significantly impair the production quality and efficiency of cold tandem rolling. Considering that the main drive system constitutes one of the energy sources of vibration, this study integrates the vertical structure of the rolling mill with the torsional structure of the main drive system for a comprehensive analysis. This study establishes an asymmetric dynamic rolling force model that accounts for the structural asymmetry of the rolling mill, the asymmetric power transmission between the upper and lower connecting shafts of the main drive system, and the long-term wear and friction conditions of the mechanical equipment. Furthermore, this study accounts for the speed differential between the upper and lower work rolls induced by torsional vibrations. Based on these interdependent parameters, this study develops a rolling mill vibration coupling model to comprehensively assess stability. The validation of the model confirms its high accuracy. Variations in rolling torque under different roll speed ratios, friction coefficient ratios, and roll diameter ratios were analyzed, along with the impact of the cross-shear zone's proportion on system stability under key rolling parameters. Furthermore, changes in rolling torque, amplitude, and the cross-shear zone during unstable operating conditions were examined. Finally, the interaction between the vertical and torsional structures was studied, providing a theoretical foundation for optimizing process parameters and mitigating vibrations in the continuous cold rolling process.

Functional properties of plastic deformation resistance of 12Kh18N10T steel

The resistance of metals and alloys to plastic deformation has functional properties, since it depends on the history of the development of deformation over time. This is especially true for hot deformation processes. At the same time, complexity of the mathematical description and lack of the necessary experimental equipment for a long time did not allow us to design functionals of this type. Currently, due to the emergence of multifunctional research complexes like Gleeble, such an opportunity has appeared. Accordingly, a methodology was developed to study the functional properties of the resistance of metals and alloys of plastic deformation, which was applied to the study of 12Kh18N10T steel. The choice of steel grade is due to the fact that the behavior of austenitic stainless steel during plastic deformation differs significantly from carbon steels. On the other hand, at present, more and more attention is being paid to the production of metal products from stainless steels. This is due, on the one hand, to the tighte­ning of the operating conditions of metal products, the development of new areas of their application and, on the other hand, a fairly high share of imports in the market of products made of austenitic stainless steels. Therefore, the study of the technological properties of such metals and alloys is relevant. At the same time, it should be noted that the most significant functional properties of the metal resistance to plastic deformation are manifested during hot deformation under continuous rolling conditions. Therefore, in this paper, the temperature range of hot plastic deformation is investigated. The results obtained can be used to determine the energy-power parameters in such processes as continuous rolling of strips in the finishing groups of strands and continuous rolling of sleeves in the lines of modern pipe rolling units.

Design and Verification of Continuous Tube Forming Process Parameters for PEEK-Based Rod Aimed at Space Manufacturing Applications

To meet the in-orbit construction needs of super-large spacecraft for ultra-long rod structures, this paper proposes an innovative on-orbit roll forming method for polyetheretherketone (PEEK)-based rod stock. This method ingeniously integrates temperature gradient control into a continuous deformation surface cavity design to achieve an efficient forming of resin rod components. A parametric model of the forming die cavity was established based on the comprehensive bending and downhill methods, and the boundary conditions for the temperature distribution gradient within the cavity were determined. Through the simulation and analysis of the PEEK rod curling and stitching forming process, the influence of the cavity configuration parameters on the forming load was determined. By constructing a test platform for the roll forming characteristics of resin rod components, the effects of different forming methods, stitching temperatures, and feed rates on forming quality and load were verified, and the main factors affecting the width of the welding zone, the roundness of the rod, and the straightness of the weld were analyzed. Experimental results show that the proposed continuous roll forming scheme can achieve an efficient and continuous forming of resin rod structures. When the length of the member is processed to 300 mm, at a formed rod diameter of 20 mm, by employing a cavity deformation zone length of 210 mm, a cavity clearance of 0.1 mm, a sheet width of 61 mm, a feed rate of 1 mm/s, and a sealing zone temperature setting of 335 °C, optimal rod forming quality can be achieved, characterized by a straightness error of 0.0133 ± 0.005 mm and a roundness error of 0.19 ± 0.07 mm. The proposal of this scheme provides a reliable basis for the continuous manufacturing of rod structures in the on-orbit construction of large space structures in terms of both the scheme and the parameter selection.

Batch process soft sensing based on data-stacking multiscale adaptive graph neural network

Abstract Soft sensing technology has found extensive application in predicting key quality variables in batch processes. However, its application in batch process is limited by the uneven batch length, the correlation of data and the difficulty in extracting the dependencies between variables and within variables. To address these issues, we propose a data-stacking multiscale adaptive graph neural network (DSMAGNN) soft sensor model. Firstly, Mutual information (MI) is used to selected quality-related variables, the 3D batch data is converted into a time-delay sequence suitable for input to the soft sensor model through the data stacking strategy, and the underlying time correlation at different time scales is preserved by incorporating the multi-scale pyramid network. Secondly, the dependencies between variables are inferred by the adaptive graph learning module, while the dependencies both within and between variables are modeled by the multi-scale temporal graph neural network. Thirdly, collaborative work across different time scales is further facilitated by the scale fusion module. Finally, the feasibility and effectiveness of the model are verified through experiments in the industrial-scale penicillin fermentation process and hot rolling process.

Investigation on the microstructure and mechanical properties of 5356 aluminum alloy wire in continuous casting direct rolling process

Investigation on the microstructure and mechanical properties of 5356 aluminum alloy wire in continuous casting direct rolling process

New route for fabricating low-carbon ductile martensite to optimize the stretch-flangeability of dual-phase steel

Traditional cold-rolling dual-phase steel (CR sheet), limited by poor stretch-flangeability as indicated by the hole expansion rate (HER), faces challenges in manufacturing complex automobile parts. To address this, a new type of hot-rolling dual-phase steel with an 800 MPa grade (manufactured by tyipical thin slab continuous casting and rolling process, TSCCR) was designed to replace the traditional one. The TSCCR sheet, with a lower carbon content of 0.047wt.%, compared to 0.093wt.% in the CR sheets, features 40.6% martensite significantly higher than 28.2% in the CR sheet. This increased martensite content, despite being softer and more ductile due to its low hardness, compensates for the tensile strength in the TSCCR sheet. Furthermore, the TSCCR sheet exhibits a unique heterostructure characterized by uneven carbon distribution from the ferrite/austenite interface to other boundaries/interfaces, estimated by the negligible partition local equilibrium (NPLE) model of ferrite transformation. This unique heterostructure diminishes the mechanical disparity between ferrite and martensite, resulting in a higher yield strength of 568 MPa, compared to 456 MPa in the CR sheet. During uniaxial tension, the ferrite and ductile martensite in the TSCCR sheet initiate cooperative plastic deformation earlier than in the CR sheet, despite initially having fewer favorable slip systems in the TSCCR martensite. The low working hardening rate of the TSCCR sheet facilitates the forming layered structure of ferrite and martensite during necking compared to the CR sheet. Consequently, the HER of the TSCCR sheet sharply increased by 144% compared to the CR sheet. This enhancement in HER can be attributed to the crack initiation area, longer crack propagation path, and higher crack propagation resistance facilitated by the ductile martensite, culminating in superior HER.

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.

Effects of Continuous Rolling and Reversible Rolling on 2.4% Si Non-Oriented Silicon Steel

The cold-rolled non-oriented silicon steel sheets with a Si content of 2.4 wt.%, produced by continuous and reversible cold rolling, were used as the experimental material. The effects of annealing temperature on the microstructure, texture, and magnetic properties were studied by optical microscopy, an X-ray diffractometer, and a magnetic property measuring instrument. The experimental results showed that the dominant texture components at the surface of both sheets were almost the same, i.e., α and γ fibers. After annealing at 920 °C for 30 s, a complete recrystallization occurred in both sheets. When annealing below 1070 °C, the average grain sizes of continuous cold-rolled sheets were slightly higher than those of reversible cold-rolled ones. Additionally, for all specimens, the recrystallization texture components were γ fiber, as well as weak α fiber, λ fiber, and Goss texture. Additionally, the difference was the texture intensity. The iron losses of the finished products of continuous cold rolling were lower than those of the finished products of reversible cold rolling with the increase in annealing temperature, and the magnetic induction was higher than that of the finished products of reversible cold rolling.

Study on the Influence of Mandrel Speed on the Titanium Tube Continuous Retained-Mandrel Rolling Process

The continuous retained-mandrel rolling process is a promising method for titanium tube production with high efficiency and a short process. The importance of mandrel as a deformation tool supporting the inner wall is crucial. This paper thoroughly examines the influence of mandrel velocity on the deformation characteristics at the groove vertex using three approaches: numerical simulation, shear-deformation observation experiments, and microstructure analysis. The following conclusions are drawn: Decreasing the mandrel velocity enhances the penetration of shear deformation into the inner wall of the titanium tube, improves thickness uniformity, and shifts the deformation mechanism near the inner wall from twinning to dislocation slip. As a result, the volume fraction of recrystallization increases from 18.4% to 42.3%. However, the mean shear strain increases first and then decreases to a certain value as the mandrel speed decreases, which is attributed to the combined influence of the cross-shear zone and the rolling force.

Investigation of bisphenol S (BPS) in packaged fish, meat, cheese, and price labels on their corresponding packages

As an alternative to bisphenol A (BPA), bisphenol S (BPS) has been used as an ink developer in thermal paper products including price labels on food packaging which have been suggested as the sources of BPS found at high levels in packaged fish samples. BPS in the printed price labels glued onto the outside of plastic film could migrate indirectly from the printed surface through the paper, adhesive and film into the food. In order to investigate if price labels could also be the sources of BPS detected in the meat samples in our previous studies, meat and other food samples packaged under different conditions were collected, and BPS in these samples together with the price labels on the corresponding packaging were extracted with solvent followed by solid phase extraction and stable isotope dilution LC-MS/MS analysis. BPS was detected at very high levels (161.7–222.4 µg/cm2) in all the five sticker type of price labels, indicating BPS being the dominant if not the sole ink developer. BPS was also detected in all the 26 continuous roll type of price labels but at very low levels (0.017–18 ng/cm2), indicating that the dominant ink developer is likely one of the other alternatives, rather than BPS. Despite BPS being detected in all price labels on packaging of fish, meat, and cheese samples, BPS was not detected or detected in only a few fish, meat, and cheese samples at levels considerably lower than the current EU specific migration limit (SML) of 50 ng/g food for BPS authorised under Regulation (EU) 10/2011.

Analytical Determination of Stick–Slip Whirling Vibrations and Bifurcations in Rotating Machinery

In rotating machinery, aerodynamic forces and oil film forces often lead to cross-coupling stiffness. This paper is aimed at studying the stick-slip whirling vibrations induced by the piecewise smooth rotor/stator frictions in a modified flexible rotor subjected to cross-coupling stiffness. Governing equations determining the sliding region and boundaries of piecewise discontinuous friction are defined. This analytical study was conducted to discuss the complex vibrations and bifurcations. Various types of sliding motions (continuous pure rolling, continuous crossing, and grazing–sliding) were observed in this research. Further, as for discussing the impacts of the parameters on nonlinear sliding vibrations, a parametric study was conducted. The obtained results reveal that with an increase in the cross-coupling stiffness coefficient, continuous pure rolling occurs earlier, and the disk vibration time around the contact regime becomes shorter. For studying the self-excited backward whirling vibration of stick–slip nonlinear motions, analytical formulations are established. Detailed vibration amplitude and frequency studies of friction-induced backward whirling vibrations were carried out. Numerical simulations were performed to compare them with the analytical solutions and to validate the results as well. The proposed theory and results provide fresh perspectives for predicting friction-induced whirlings and creating proper designs for turbo machinery.

Research and application of the flatness target curve discrete dynamic programming based on two-dimensional decision making

The flatness target curve (FTC) is a fundamental process model in cold rolling flatness control, which directly affects the quality control effect of the strip. The accurate and efficient setting of the flatness target curve is the key to ensuring continuous rolling and is a common problem faced by various production companies. This paper establishes a discrete dynamic planning (DDP) setting method for FTC with two-dimensional decision-making. To quantitatively analyze the roles of the coefficients in the FTC, the preprocessing process is established using standardized processing methods and statistical analysis methods. The flatness target curve discrete dynamic programming (FTC-DDP) is based on Bellman optimization theory with a dual structure of local and system decision-making. The decision-making functions are established based on the effect of each coefficient on FTC geometric characteristics. The concepts of “curvature factor” and “wedge factor” are innovatively proposed to obtain the decision-making value functions. The regression analysis establishes the solution equations of even number coefficients, odd number coefficients, and gain coefficients, respectively. Roll bending and tilting roll analyze the FTC’s ability to correct flatness defects. Meanwhile, utilizing a 1450 mm five-stand six-roll cold rolling mill, it is verified that FTC-DDP can quickly and accurately set the FTC, which provides an effective solution for obtaining high-precision and high-quality cold-rolled strips. Application results show that FTC-DDP can reduce the difficulty of setting up FTC by more than 70 %, reduce the setup time to milliseconds, and improve the setup accuracy by more than 50 %.

Study of the rolling wetting behavior of droplets on surfaces with T-shaped microstructures

The regulation of droplet wetting behavior encompasses multiple professional disciplines, and the surface microstructure has become the preferred approach for controlling droplet wetting behavior. Bionic studies have revealed that springtails can effortlessly move in water because of the T-shaped microstructures on their skin, which prompted the design of various T-shaped microstructures to effectively regulate droplet wetting behavior. Although the static wetting theory for T-shaped microstructure surfaces is well understood, the dynamic wetting theory regarding droplet rolling remains unexplored. This study aims to investigate the rolling behavior of droplets on inclined surfaces with T-shaped microstructures through theoretical analysis and numerical simulation. By analyzing the comprehensive energy transformation and gas-liquid interface morphology during the tilting processes, we revealed the mechanism by which the geometric parameters of the T-shaped microstructures influence the droplet rolling behavior and constructed an energy prediction analysis model for the final droplet morphology. The results showed that reducing the cantilever height, increasing the structural spacing, and enlarging the droplet size facilitated continuous rolling of the droplets. Additionally, we discovered that the driving energy for droplet rolling on inclined surfaces with T-shaped microstructures originates from the surface free energy. The maximum surface free energy of a droplet often occurs when the droplet begins to roll.

Motion behaviors of droplets containing Au nanoparticles on a superhydrophobic laser-induced graphene surface

The movement of nanoparticle-containing droplets on solid surfaces significantly affects the distribution of the nanoparticles and is of great interest in the fields of two-phase separation, biosensing detection, inkjet printing, and microarrays. There has been little research on the initiation and motion behaviors of colloidal droplets containing nanoparticles on superhydrophobic surfaces. Here, we prepare superhydrophobic laser-induced graphene (LIG) surfaces with excellent depinning effects using an extremely simple method and explore the formation mechanism of the depinning-LIG surfaces. The reduction of nano-graphene fibers and the increased hydroxyl group ratio after alcohol modification further enhance the hydrophobic properties of depinning-LIG, reducing its surface adhesion. The initial and continuous motion of droplets containing Au nanoparticles (AuNPs) on these superhydrophobic surfaces under airflow is studied using high-speed microscopy. The coupling effects of the droplet size, surface properties, airflow velocity, and nanoparticles on the droplet motion behaviors are analyzed. The dimensionless parameter G is incorporated to obtain the partition diagram of AuNP droplet motion behaviors on depinning-LIG surfaces, which delineate the critical conditions for droplet “oscillation,” “initiate sliding,” and “continuous rolling” as a function of system parameters. For AuNP droplets, the viscous force Fγ,p exerted by the nanoparticles on the contact line significantly affects the droplet movement behaviors. In addition, a mathematical model about the competition of dynamic forces and resistance is established to describe the motion of AuNP droplets, and the critical conditions for different motion behaviors of the droplet are clarified to guide practical applications.