Rolling Speed Research Articles

Microstructure and magnetic properties of surfactant-assisted ball milling NdFe8Co2Mo2 powders and their nitrides

The NdFe8Co2Mo2 alloy ribbons were prepared by melt-spinning. The powder was prepared through surfactant-assisted ball milling, followed by nitriding to produce the NdFe8Co2Mo2Nx alloy. The alloy ribbons grain size decreases as the copper roller speed increases. At the speed of 30 m/s, a pure 1:12 phase alloy ribbons were produced. The grain size decreases with increasing the ball milling time, but the composition phases almost unchanged of the alloy powder. The grain size refine after nitriding, but the grain volume expands when the nitriding temperature exceeds 500 °C. With increasing ball milling time and nitriding temperature, the remanence (Mr) and coercivity (Hc) of the alloy powder increase first and then decrease. The alloy powder obtained from ball milling for 3 h after nitriding at 475 ℃ for 3 h, resulting in Mr was 44.43 Am2/kg, Hc was 0.434 T, and saturation magnetization (Ms) was 74.89 Am2/kg.

The Study on Annealing Temperature and Rolling Speed Effects in Relation with Microstructure, Mechanical Properties and Surface Quality of Hot Rolled S450J0 Steel

The Study on Annealing Temperature and Rolling Speed Effects in Relation with Microstructure, Mechanical Properties and Surface Quality of Hot Rolled S450J0 Steel

Effect of Cu-doping on the microstructure and magnetic properties of low-cost MM-Fe-B melt spun ribbons

In this paper, MM-Fe-B ribbons with different MM contents were prepared by melt spun technique at a fixed copper roll speed of 25 m/s. The maximum magnetic energy product of the MM15Fe78B7 ribbon is 9.22 MGOe and the coercivity is 6005 Oe. With the increase of MM contents, the coercivity of the magnet was increased, and the highest coercivity reached 9352 Oe in MM18Fe75B7. In addition, the microstructure and magnetic properties of Cu-doped MM15Fe78-xB7Cux (x = 0, 0.4, 0.6, 1 at.%) ribbons were systematically investigated. The results show that the introduction of Cu can suppress the formation of α-Fe soft magnetic phase in the melt spun ribbons. When the Cu content is 0.4 at.%, the grain size decreased from 61 nm to 44 nm, and the coercivity was improved from 6005 Oe to 8527 Oe, which is an increment of about 42 %, whereas the remanence and the magnetic energy product can remain basically unchanged. The addition of Cu element can not only refine the grain size, but also facilitate the enhancement of the homogeneity of the microstructure of the ribbons.

Influence of Rolling Speed on the Mechanism of Adiabatic Shear Band Formation and Plastic Flow in Polyethylene Terephthalate Films

Influence of Rolling Speed on the Mechanism of Adiabatic Shear Band Formation and Plastic Flow in Polyethylene Terephthalate Films

Analysis and Prospects of Lubrication and Friction Characteristics in Cold Strip Rolling: A Review

Lubrication and friction are the core processes in cold strip rolling, which are the key links to realizing the stable production of high‐quality strips, reflecting country advanced level in rolling technology. This review investigates the crucial properties of lubrication and friction in cold strip rolling by analyzing the mechanism, characterization methods, and influencing factors. The lubricant forms an oil film on the surface of rolls and strips based on the lubrication dynamics and tribology theory, changing the asperity contact state in the loaded roll gap, leading to changes in friction characteristics. Oil film thickness and coefficient of friction (COF) are crucial parameters for characterizing and judging the characteristics of lubrication and friction, theoretical calculations have become the core analytical method, and the study of the measurement method is still a great challenge. Parameters like rolling speed and oil viscosity affect the lubricant distribution and asperity contact in the loaded roll gap, changing the lubrication and friction state. The influence of parameters is strongly linked to the experimental or rolling environment. Prospective research trends on lubrication and friction in cold strip rolling are presented based on the status of research on lubrication and friction characterization.

Rolling Motion of Rigid Skyrmion Crystallites Induced by Chiral Lattice Torque.

Magnetic skyrmions are topologically protected spin textures with emergent particle-like behaviors. Their dynamics under external stimuli is of great interest and importance for topological physics and spintronics applications alike. So far, skyrmions are only found to move linearly in response to a linear drive, following the conventional model treating them as isolated quasiparticles. Here, by performing time and spatially resolved resonant elastic X-ray scattering of the insulating chiral magnet Cu2OSeO3, we show that for finite-sized skyrmion crystallites, a purely linear temperature gradient not only propels the skyrmions but also induces continuous rotational motion through a chiral lattice torque. Consequently, a skyrmion crystallite undergoes a rolling motion under a small gradient, while both the rolling speed and the rotational sense can be controlled. Our findings offer a new degree of freedom for manipulating these quasiparticles toward device applications and underscore the fundamental phase difference between the condensed skyrmion lattice and isolated skyrmions.

Research on the Wear State Detection and Identification Method of Huller Rollers Based on Point Cloud Data

Throughout the huller shelling process, the rubber rollers progressively deteriorate. The velocity of the rubber rollers decreases as the distance between the rollers rises. These modifications significantly influence the rate at which rice hulling occurs. Hence, the implementation of real-time online detection is crucial for maintaining the operational efficiency of the huller. Currently, the prevailing inspection methods include manual inspection, 2D vision inspection, deep learning methods, and machine vision methods. Nevertheless, these conventional techniques lack the ability to provide detailed information about the faulty components, making it challenging to conduct comprehensive defect identification in three dimensions. To address this issue, point cloud technology has been incorporated into the overall detection of the working condition of the huller. Specifically, the Random Sample Consensus segmentation algorithm and the adaptive boundary extraction algorithm have been developed to identify abnormal wear on the rubber rollers by analyzing the point cloud data on their surface. A solution technique has been developed for the huller to compensate for the speed of the rubber rollers and calculate the mean values of their radii. Additionally, a numerical simulation algorithm is proposed to address the dynamic change in the roller spacing detection. The results show that point cloud data can be utilized to achieve real-time and precise correction of anomalous wear patterns on the surface of rubber rollers.

Vertical vibration analysis of rolling interface based on dynamic rolling force with variable friction characteristics

This study investigates the impact of variable friction characteristics at the rolling interface on the vertical vibration of plate and strip rolling mills. Based on the optimized Karman equilibrium theory, a dynamic rolling force model considering the front and back tension, elastic stretching, and rolling speed was established. The amplitude-frequency response equation of rolling mill system is solved by multi-scale method, and the influence of main parameters on vertical vibration of rolling mill system is analyzed. The results show that the increase of the first stiffness coefficient of dynamic rolling force leads to the decrease of the principal common amplitude of the system. On the contrary, when the third stiffness coefficient increases, the system exhibits a jump phenomenon. When the third stiffness coefficient of dynamic rolling force is reduced within a certain range, a stable and unique solution is obtained without jumping phenomenon. Moreover, the smaller the damping coefficient of the upper and lower roller system is, the larger the vibration amplitude is and the jump phenomenon occurs. Decreasing the external disturbance force can effectively reduce the system’s vertical vibration amplitude and suppress the resonance. In addition, with the change of external disturbance force, the roll system of the rolling mill shows a variety of complex motion states, such as periodic motion, double-periodic motion, and chaotic motion. The research results provide an effective theoretical reference for the suppression of vertical vibration of rolling mill.

Ensembled surrogate-assisted material extrusion additive manufacturing for enhanced mechanical properties of PEEK

Purpose This study aims to improve the mechanical properties of an object produced by fused deposition modelling with high-grade polymer. Design/methodology/approach The study uses an ensembled surrogate-assisted evolutionary algorithm (SAEA) to optimize the process parameters for example, layer height, print speed, print direction and nozzle temperature for enhancing the mechanical properties of temperature-sensitive high-grade polymer poly-ether-ether-ketone (PEEK) in fused deposition modelling (FDM) 3D printing while considering print time as one of the important parameter. These models are integrated with an evolutionary algorithm to efficiently explore parameter space. The optimized parameters from the SAEA approach are compared with those obtained using the Gray Relational Analysis (GRA) Taguchi method serving as a benchmark. Later, the study also highlights the significant role of print direction in optimizing the mechanical properties of FDM 3D printed PEEK. Findings With the use of ensemble learning-based SAEA, one can successfully maximize the ultimate stress and percentage elongation with minimum print time. SAEA-based solution has 28.86% higher ultimate stress, 66.95% lower percentage of elongation and 7.14% lower print time in comparison to the benchmark result (GRA Taguchi method). Also, the results from the experimental investigation indicate that the print direction has a greater role in deciding the optimum value of mechanical properties for FDM 3D printed high-grade thermoplastic PEEK polymer. Research limitations/implications This study is valid for the parameter ranges, which are defined to conduct the experimentation. Practical implications This study has been conducted on the basis of taking only a few important process parameters as per the literatures and available scope of the study; however, there are many other parameters, e.g. wall thickness, road width, print orientation, fill pattern, roller speed, retraction, etc. which can be included to make a more comprehensive investigation and accuracy of the results for practical implementation. Originality/value This study deploys a novel meta-model-based optimization approach for enhancing the mechanical properties of high-grade thermoplastic polymers, which is rarely available in the published literature in the research domain.

The Kinematic and Electromyographic Analysis of Roller Skating at Different Speeds on a Treadmill: A Case Study.

Elite athletes in speed roller skates perceive skating to be a more demanding exercise for the groin when compared to other cyclic disciplines, increasing their risk of injury. The objective of this study was to monitor the kinematic and electromyographic parameters of roller speed skaters, linearly, on a treadmill, and to compare different skating speeds, one at 20 km/h and one at 32 km/h, at a 1° inclination. The acquisition was carried out by placing an inertial sensor at the level of the first sacral vertebra, and eight surface electromyographic probes on both lower limbs. The kinematic and electromyographic analysis on the treadmill showed that a higher speed requires more muscle activation, in terms of maximum and average values and co-activation, as it not only increases the intrinsic muscle demand in the district, but also the athlete's ability to coordinate the skating technique. The present study allows us to indicate not only how individual muscle districts are activated during skating on a surface different from the road, but also how different speeds affect the overall district load distributions concerning effective force, which is essential for the physiotherapist and kinesiologist for preventive and conditional purposes, while also considering possible variations in the skating technique in linear advancement.

The evolution of tire-road wear particles and road surface texture under rolling friction

Traffic-related non-exhaust emissions are an important part of air pollution, which can adversely affect human health when inhaled. Tire-road wear is a significant source of these emissions and originates from tire-road friction. To gain a deeper understanding of the relationship between tire-road wear particles and road surface texture under rolling friction, this study conducted long-term durability experiments using a Model Mobile Load Simulator at 1/3rd scale to form a closed environmental test system. The experiments were conducted under 30°C, 50 % relative humidity, 0.7 MPa tire-ground pressure, and 5.4 km/h rolling speed. Based on an analysis of asphalt concrete-13 Marshall samples’ British Pendulum Number (BPN) value, Mean Texture Depth (MTD), wear particle size distribution, particulate matter (PM) concentration, and thermogravimetric analysis during 1600,000 rolling times, this study draws the following conclusions: This indoor research has indicated that the weight ratio of tire and asphalt wear to aggregates and mineral fillers is approximately 4.5:5.5 (after stabilization). When the tire contacts the aggregate exposed after asphalt film peeling, it significantly increases PM10 concentration. Under the rolling friction of the tire-road contact, the quality loss of asphalt concrete follows an exponential decay curve with an R2 of 0.99. Road (asphalt concrete pavement) wear per square meter of tire-road contact was 5.32×10^−4 g and 2.13×10^−4 g (before and after asphalt film peeling). It is hoped that this study will contribute to the field of tire-road wear, including non-exhaust emissions, and provide methods and theoretical support for mitigating re-suspension dust.

Automatic alignment of elastic slender belt caused by crown roller in two-roller belt system

To clarify the relationship between the geometry of the crown roller and the automatic alignment of the belt in a two-roller belt system that includes a crown roller, we develop an analytical method that calculates the lateral belt position. The calculated results based on this method are in good agreement with the experimental results, thereby validating the analysis method developed. The automatic alignment of the belt is caused by the difference in the peripheral speed of the crown roller in the axial direction. The automatic alignment effect improves as the radius of curvature and the diameter of the crown roller decrease. Furthermore, we show that the effect of belt tension on the automatic alignment of the belt has a slight effect on the time until the belt moves to the roller center position but does not have a significant effect on the automatic alignment of the belt.

Effect of addition of Ce and accumulative roll bonding on structure-property of the Mg-Ce-Al hybrid composite and its prediction and comparison using artificial neural network (ANN) approach

Abstract Light alloys play a crucial role in realizing the national strategy for energy conservation and emission reduction, as well as promoting the upgrading of manufacturing industries. Mg/Al composite laminates combine the corrosion resistance and ductility of aluminium alloy with the lightweight characteristics of magnesium alloy. The addition of Ce (rare earth elements) can improve the mechanical properties of magnesium via grain refinement and improve the ductility of the hybrid composites. In the present work, an investigation on addition of Ce into the Mg/Al matrix through Accumulative Roll Bonding (ARB) has been presented. The Mg/Ce/Al hybrid composite consists of Mg-4%Zn alloy and Al 1100 alloy with 0.2% Ce particles added between the dissimilar layers. The changes occurred in the evaluation of microstructure, corrosion and mechanical properties of the Mg/Ce/Al hybrid composite as a result of deformation process and also the addition of Ce have been explicated. The ARB parameters: temperature, rolling speed, percentage reduction, and aging time, have been studied. An increase of about 2.36 times in strength and hardness of the hybrid composite, has been reported. Further, the structure–property relations in the Mg/Ce/Al hybrid composites were aslo predict and compare using machine learning models: Decision Tree and Multi-Layer Perceptron (MLP) models.

A stretching apparatus with broad strain rate and temperature ranges for in-situ x-ray scattering measurements of polymers

A stretching apparatus capable of conducting tensile tests over a broad strain rate range (10−3–250 s−1) and a wide temperature range (−75–250 °C) has been designed for polymeric materials, in particular the polymeric films. Specifically, this stretching apparatus can be combined with in situ ultrasmall-, small-, and wide-angle x-ray scattering (USAXS/SAXS/WAXS) measurements. The sample stretching is achieved through the synchronized rotation of rolls, powered by servo motors. The output electrical signal extracted from a torque sensor, when combined with the rotational speed of rolls and initial sample dimensions, enables the determination of the relationship between engineering stress (σ) and Hencky strain (ε). With the sample chamber and precise control loop, the prescribed temperature can be achieved using either hot airflow for heating or cold liquid nitrogen flow for cooling. By integrating this stretching apparatus with a high brilliance x-ray source at beamline BL10U1 in Shanghai Synchrotron Radiation Facility (SSRF) and detectors featuring ultrafast acquisition rates, it becomes possible to monitor multiscale structure evolutions of polymeric samples under harsh conditions involving high-speed loading combined with varying temperatures.

Research on the service life of bearings in the gearbox of rolling mill transmission system under non-steady lubrication state

A rolling bearing plays a key role in the gearbox of the cold rolling mill transmission system. As a result, the degradation and failure of bearings can lead to unplanned shutdowns of the entire rolling mill system. Since on-site cold rolling mills work usually in non-steady lubrication rolling conditions originating form variations of multiple parameters, the uncertainty affecting bearing performance in a cold rolling mill transmission system increases, making it more difficult to assess health status and predict the remaining service life of bearings, Therefore, by establishing a coupling model describing the relationship for the rolling mill and normal /faulty gearboxes under non steady rolling conditions, quantitatively studies the influence of various rolling parameters of a rolling mill on the fatigue service life of bearings in the gearbox of the rolling mill transmission system, and verify the effectiveness of linear cumulative damage theory for bearing fatigue service life through experiments and on-site bearing vibration data. The results indicate that as the thickness of the strip steel inlet, lubricant viscosity, and rolling speed increase, or the thickness of the strip steel outlet and rolling roll radius decrease, the service life of bearings gradually decreases. As the fluctuation amplitude of various rolling parameters in the cold rolling mill increases, the service life of bearings in the gearbox of the rolling mill transmission system gradually shortens. Moreover, when the rolling parameter value or fluctuation amplitude increases to a specific values, the remaining service life of bearings will sharply decrease. Under the same rolling conditions, the service life of bearings in gearboxes with faults decreases more significantly than that in normal gearboxes.

块茎收获物清选机的设计与模拟分析

In this paper, a screening machine was designed to remove the impurities in the tuber harvest, which integrates the functions of vibration screening, air separation, and flexible polishing. Discrete element simulation analysis was carried out to investigate the movement of tuber harvest and soil in the machine and the effect of polishing and removing impurities, the rationality of the structure, and the size were verified. Orthogonal tests were designed and carried out, with the rate of impurity, loss, and crushing as indicators and crank speed, impeller speed, and polishing roller speed as factors. The optimum working parameters were obtained: crank speed 280.12 r/min, impeller speed 1056.27 r/min, polishing roller speed 405.02 r/min, the impurity content was 0.29%, the loss rate was 1.01%, and the breakage rate was 0.11%. Through experimental verification, the actual value and theoretical value are basically the same, which verifies the rationality.

Role of strain softening and viscoelastic memory for the rolling friction of two tire tread compounds.

Rolling friction is of great importance for many applications, such as tires and conveyor belts. We study the rolling friction for hard cylinders rolling on flat rubber sheets. The rolling friction depends on the number of rolling cycles, the rolling speed, and the temperature. We show that when the rubber is cooled down below the glass transition temperature, the deformations of the rubber surface are frozen-in, resulting in a non-flat rolling track where uphill and downhill rolling movements strongly affect the rolling force. The experimental data are analyzed using the Persson rolling friction theory; good agreement with the experiments is obtained when the non-linear (strain-softening) properties of the viscoelastic modulus are taken into account.

Detection of uniformity and spatial correlation of subgrade compaction quality based on intelligent compaction technology

Intelligent compaction uniformity and spatial correlation detection of subgrade is an important part of intelligent compaction technology. In this paper, a subgrade compaction uniformity detection method is established based on the univariate statistical normal distribution 3σ criterion, and further a subgrade compaction quality spatial correlation detection method is established by the multivariate statistical spatial semi-variance function, and finally the established subgrade compaction uniformity and spatial correlation methods are verified by field tests. The subgrade compaction uniformity and spatial correlation are detected based on field tests. The results obtained in this paper show that the 3σ criterion based on normal distribution can be used for the detection of intelligent compaction uniformity of subgrade, and the field test results are verified by this method, and all the intelligent compaction uniformity of subgrade meets the requirements; considering the construction efficiency and the influence between rollers, it is recommended that the rolling speed should be in the interval range of 2–3 m/s, and the construction spacing of rollers is maintained at 10 m and above.

The Design and Optimization of a Peanut-Picking System for a Fresh-Peanut-Picking Crawler Combine Harvester

In view of the problem that peanut harvesting in hilly areas mainly involves fresh food, and that the peanut-picking purity rate is low and there is high breakage in the peanut-harvesting process, key components such as the picking system of a fresh-peanut-picking crawler combine harvester, the picking tooth, and the concave screen were designed, and ANSYS Workbench 2020 software was used to check the reliability of the picking roller under working conditions in hilly areas. In the process of equipment operation, the picking purity rate and breakage rate were the main evaluation indexes, and the Box–Behnken test method was used to study the speed of the peanut-picking roller, the feeding amount, and the picking gap as the test factors. The results showed that the picking purity rate is 98.95%, with an error margin of 0.98%, compared to the predicted value under the conditions of 342 r/min speed, 0.75 kg/s feeding amount, and 32 mm picking gap. The breakage rate is 4.23% and the error is 0.4% compared with the predicted value, indicating that the optimized model is reliable and predictive. This study provides a theoretical basis for the optimal design of the peanut-picking system of peanut-picking combine harvesters in hilly areas.

A sustainable mineral process for silicon and quartz recovery from quartz crucible waste ash via electrical separation

Driven by the explosive development of the photovoltaic (PV) industry, the treatment of the quartz crucible waste ash (QCWA) from monocrystalline silicon rod production must be considered to combat the shortage of silicon materials and promote sustainable development. In particular, the loss of grade 4 N high-purity silicon in QCWA is a frustrating fact for the silicon supply chain. In this work, an electrical separation process is proposed for the recovery of silicon and quartz from QCWA to realize waste resource reutilization. The charging processes and forces in the feed QCWA are first analyzed. Then, the electric field distribution during electrical separation is simulated to clarify the movement models of silicon and quartz particles and formulate reasonable electrical separation parameters. After systematic theoretical analysis, calculation, and simulation, electrical separation experiments were conducted. The results prove that the content of silicon in the concentrate and the corresponding content of quartz in the tailing respectively exceeded 93 % and 61 % under a particle size of 80 ∼ 120 mesh, a voltage of 40 kV, and a roll speed of 75 r/min. This work demonstrates that electrical separation is a sustainable process that could be recommended for silicon and quartz recovery from QCWA.