Abstract:This study develops a computational model to predict the yield strength of three-layer stainless steel/carbon steel/stainless steel clad plates based on experimental data from varied hot rolling processes.The two-pass rolling schedule involved a first pass at reduction rates of 25%,30%,and 35%,followed by a second pass at a constant 20%reduction.Results show that increasing the first-pass reduction rate reduced the average grain diameter of the carbon steel substrate from 14.74 μm to 8.95 μm,while the average kernel average misorientation(KAM)initially decreased then increased(1.72°,1.01°,and 1.27°,respectively).Conversely,the average grain diameter of the stainless steel cladding first increased then decreased(23.67 μm,40.49 μm,and 28.64 μm,respectively),with a corresponding increase in average KAM value(0.48°,1.06°,and1.10°).The calculated yield strengths(300.44 MPa,305.25 MPa,and 333.55 MPa)all fell within 7.1%of the experimental values(280.61 MPa,325.83 MPa,and 355.51 MPa),validating the model's accuracy.Analysis confirms that the material's yield strength is simultaneously influenced by grain diameter and KAM,with grain diameter being the predominant factor.Specifically,yield strength is inversely proportional to grain diameter and directly proportional to the KAM value.

Abstract:During the operation of scraper conveyors,the severe wear problem of the chute wall-scraper friction pair and the entire machine has always been a key bottleneck restricting its efficient and stable operation.The research aims to solve the above-mentioned wear problems through effective technical means,enhance the wear resistance of the chute wall,and further provide theoretical support and practical guidance for the optimal design of scraper conveyors.The research adopts a combination of wear tests and simulation analysis methods to systematically carry out relevant research work.The results show that the bionic structure has a significant effect on improving the wear resistance of the chute wall.Among them,the bionic groove structure designed on the surface of the chute wall can greatly reduce the wear amount.It is also found that in actual production design,the selection of bionic structures cannot be based solely on wear resistance as a single indicator.It is necessary to comprehensively consider multiple factors such as differences in mine environments,coal quality characteristics,operating conditions,selection of manufacturing materials,and cost control.A single indicator is difficult to fully evaluate its application value,which also highlights the important theoretical significance and practical guiding value of constructing a multi-dimensional comprehensive evaluation system for optimizing the selection of bionic structures.

Abstract:A wireless monitoring system based on 5G strain and temperature was designed to address the difficulty of monitoring the reheater valve casing in thermal power units.High-temperature strain gauges and K-type thermocouples were selected.A conditioning and acquisition system for strain and temperature at the edge was designed,which was connected to a 5G industrial gateway for high-bandwidth,low-latency remote data transmission.The data could be stored on-site and in cloud servers.A Vue+Spring Boot IoT service program was developed to provide remote access functionality for multiple users in different locations.Experimental verification showed that the network latency was in the millisecond range,and the data transmission accuracy reached 99.7%,The deformation model with an order of 2 has better predictive performance,and the maximum principal strain model has lower errors,meeting the requirements of wireless monitoring of high-temperature micro-strain in the reheater valve casing.

Abstract:With the rapid development of China's rail transit field,the demand for large shaft parts has increased sharply,and the problems of low efficiency and insufficient accuracy of traditional production processes have become increasingly prominent.Although the large-scale shaft wedge rolling mill can achieve efficient production,its eccentric roll system and large structure cause vibration during operation,which seriously affects the machining accuracy and equipment life.To this end,this paper proposes a"mechanism+data"hybrid driven digital twin modeling method,which reveals the vibration response mechanism of the shaft wedge rolling mill system by establishing its dynamic model.A high-fidelity digital twin 3D model was built based on SolidWorks and MapleSim to realize the virtual mapping of equipment structure and dynamic characteristics.Combined with the distributed sensor network and industrial PLC system,a comprehensive data collection platform is built to form a three-dimensional framework for the collaboration of physical environment,virtual environment and data environment.Through the digital twin platform,the real-time monitoring of the running status of the rolling mill and the optimization of process parameters are realized,which reduces the vibration amplitude of the roll by 60.12%,and significantly improves the stability of the equipment and the product quality.This study provides an effective solution for the intelligent regulation and control of large-scale shaft wedge rolling mill.

Abstract:In order to meet the lubrication requirements of sliding bearings in wind turbine gearboxes,an optimization design method for lubrication flow distribution of planetary wheel sliding bearings in wind turbine gearboxes is proposed.Based on the analysis of heat generation in the lubrication system of wind turbine gearboxes,a lubrication flow distribution model for planetary wheel sliding bearings was established.By designing a set of factorial simulation experiments,the influence of pipeline parameters on lubrication flow distribution was studied.On this basis,considering the impact of uneven flow distribution in the pipeline,a genetic algorithm was used to optimize the design of the sliding bearing lubrication pipeline,and a set of optimal design parameters for the lubrication pipeline were obtained through parallel simulation calculations in Matlab and Simulink.The simulation results show that after optimizing the lubrication pipeline of the pin shaft oil outlet,the deviation degree of each outlet flow rate has been reduced from 40.04%to 0.015%,and the imbalance of flow rate has been greatly improved.This study provides a new method for flow distribution in the lubrication system of sliding bearings.

Abstract:To enhance the lubrication performance of compressor oils under extreme operating conditions,this study employed polytetrafluoroethylene(PTFE)nanoparticles as protective additives.Nanocomposite lubricants with varying volume fractions(0.5-3 vol%)of PTFE were prepared via ultrasonic dispersion and systematically investigated for their dispersion stability,tribological properties,and physicochemical characteristics.Experimental results demonstrated that at 2 vol%PTFE,the nanoparticles exhibited exceptional dispersion stability in the base oil.Under a 1 kN load,the friction coefficient of the lubricant decreased by 22.5%,accompanied by shortened oil film rupture time and significantly improved extreme-pressure(EP)performance.At low temperature(20℃),the viscosity increased by 26.09%with PTFE addition,while minimal viscosity variation occurred at high temperature(80℃),confirming its wide-temperature applicability.Improvements in acid number and copper strip corrosion rating(from Class 1b to 1a)validated enhanced oxidation resistance and anti-corrosion capabilities.FTIR analysis revealed no chemical structural changes in the base oil after PTFE incorporation.The on-site experimental test results demonstrate that the addition of PTFE protective fluid reduced the electrical energy consumption per unit output of shale gas by 13.25%.

Abstract:To address issues such as bending and folding during the lower coiling tail-end process of steel strip finishing lines,an optimized method has been proposed.Without increasing equipment design and manufacturing costs,this method effectively resolves defects in traditional methods by adjusting equipment processing sequences and optimizing roller shapes.Additionally,accurate functional relationships between strip tail-end length and coil diameter are obtained through graphical methods and software fitting,enabling precise control of strip tail positions during the lower coiling tail-end process.This method has been successfully applied in engineering practice,achieving a 100%success rate in tail positioning and significantly improving strip steel quality and yield.

Abstract:In response to the high-precision control requirements of the electro-hydraulic position servo system for the coil car in the steel industry,a composite control strategy of sliding mode control and Linear Extended State Observer(LESO)is proposed to solve the problem of insufficient control accuracy of PID controller in nonlinear and multi operating conditions.By establishing the mathematical model of the valve-controlled cylinder and designing the sliding mode control and Linear Extended State Observer,the system disturbances and state variables are estimated in real time.The results show that under multiple working conditions of the sliding mode+LESO control strategy with the weight of 10-30 t steel coils and the target displacement of 500-1 200 mm,the control accuracy decreases with the increase of load and displacement.However,the absolute deviation of the actual displacement is less than 0.003.It can effectively suppress the chattering and adapt to complex working conditions,and the control effect is significantly better than PID control.It has stronger robustness.

Abstract:Aiming at the appearance of roll trace and external folding defects in the stretch reducing unit of a certain steel pipe company due to over-filling,the stretch reducing process of 18 stands of typical specification Φ73 mm×5 mm thin-walled tubes of T22 steel was simulated using the FE analysis software Simufact based on the existing equipment,and the metal flow,temperature distribution,stress/strain,wall thickness distribution and groove filling of the rolled tube were analyzed.Simulation results show that during the stretch reducing process of the thin-walled tube,the metal in the deformation zone of the working stand from R8 to R14 comes into contact with the roller ring of the roll,resulting in over-filling of the groove.By optimizing the width of the groove and the local curvature,a polygonal groove structure was designed,which solved the over-filling problem and ensured the accuracy of the wall thickness,and verified its universality for the stretch reducing process of the Φ73 mm×13 mm thick-walled tube.The results show that during the stretch reducing process of the thin-walled tubes using the groove optimization scheme,no over-filling of the groove occurs.The longitudinal average wall thickness non-uniformity has decreased by 0.75%compared to the original scheme.Thetransversewall thickness non-uniformity of the thick-walled tube is 2.83%,which is 0.47 percentage points lower than that of the original scheme,while the P value of the inner hexagonal degree only increases by 4.85%,which demonstrates that the optimization scheme effectively reduces the defects of roll trace and external folding of steel pipes and has good engineering application value.

Abstract:The bucket beam is the key load-transferred component between the lifting wire rope and the bucket of the excavator.Improving the stiffness,strength and service life of the bucket beam is of great significance to enhance the operation reliability of the excavator.To address the problems of easy fracture at the root of the ear plate in the widely used of the cast bucket beam,a welded box type bucket beam was designed,and its stiffness and strength were checked by Finite Element Analysis.A parameterized model of welded bucket beam was established,with the plate thickness of key parts of the bucket beam as the design variable.The optimization objective was to minimize the self weight,stiffness,and strength of the bucket beam.The second-generation non inferiority sorting genetic algorithm was used for multi-objective parameter optimization.After optimization,the bucket beam reduced its self weight while increasing its stiffness and strength by 1.24％and 9.80％respectively.

Abstract:Addressing the insufficient process lubrication and cooling capacity encountered during the production of ultra-high-strength steel using a six-stand tandem cold mill,a systematic investigation is conducted from the perspectives of emulsion parameter control mechanisms and multi-objective coordinated optimization.A dynamic adjustment method for process lubrication regimes based on a combination of mechanism modeling and intelligent optimization is proposed.First,a lubrication oil film thickness prediction model is constructed.This model comprehensively considers the non-linear effects of concentration,temperature,and flow rate parameters on the base oil's dynamic viscosity,quantitatively characterizes the mapping relationship between process parameters and the friction coefficient,and reveals the critical transition mechanism of oil film thickness with variations in rolling load and rolling speed.To address the multi-variable and strong-coupling problems in process parameter optimization for six-stand mills,the Particle Swarm Optimization(PSO)algorithm is introduced for global optimization.Industrial verification demonstrates that the optimized process lubrication regime significantly improves the consistency of lubrication conditions between the upper and lower surfaces of the strip,effectively suppressing thermal skid marks and slippage phenomena in critical stands.The cooling capacity of the emulsion system is systematically released,and rolling temperature rise and shape fluctuations are significantly reduced,providing technical support for the stable production of thin-gauge ultra-high-strength steel products.

Abstract:This research establishes a high-precision measurement and visualization online contour and surface quality detection system for H-beams using a multi-color light source cross 3D imaging system device,360°multi camera point cloud stitching technology,and real-time dynamic compensation technology.Propose a surface defect image processing method based on 2D+3D multi-dimensional information fusion,attaching 3D depth information to 2D grayscale images,solving the problem of traditional machine vision methods that can only perform qualitative detection but not depth detection,achieving"qualitative"and"quantitative"detection with a defect detection rate of 100％.By using small sample data augmentation methods and classification priority network methods,the problems of insufficient feature extraction information and insufficient data samples are solved to ensure the recognition rate of key defects and general defects in H-beams.Effectively solved the problems of appearance size and surface defect detection for various specifications of steel products,ensuring inspection accuracy while reducing the labor intensity of workers.

Abstract:During the rolling process of steel strips,factors such as production technology,processes,and environmental conditions can easily lead to surface defects,including cracks,impurities,spots,scratches,and the embedding of oxides.To improve the efficiency and accuracy of surface defect detection on steel strips,an improved Prewitt operator-based algorithm,addressing the issue of low edge precision in traditional Prewitt edge detection methods.The proposed algorithm first uses the USM algorithm to enhance image contrast,followed by bilateral filtering for noise reduction.Next,an improved four-direction Prewitt operator is applied to detect edge features,and thresholding is used to binarize the image.Finally,an edge refinement algorithm is employed to produce the final detection image.Experimental results demonstrate that this algorithm effectively extracts defect edge information.

Abstract:In response to the demand for large-scale converter and accelerated smelting pace,China National Heavy Machinery Research Institute Co.,Ltd.has successfully developed a large-diameter gas dry cylindrical electrostatic precipitator for the purification and recovery of primary flue gas from converters.The electrostatic precipitator adopts an explosion-resistant plug-flow structure and integrates multiple key technologies,including numerically simulated design of gas distribution devices,optimized configurations of electrode plates and wires(ZT24 anode plates with upgraded B8 and V15 cathode wires),a novel ash-scraping device,an improved cathode rapping system,and an efficient full-DC high-voltage power supply with variable impedance.Engineering applications shows that the equipment can achieve the ultra-low emission target of stable dust concentration in flue gas below 10 mg/Nm3,and meet the requirements for long-term safe and stable operation.At present,cylindrical electrostatic precipitators with a diameter of 13.5 m have been successfully applied in multiple large-scale converter projects,significantly improving dust removal efficiency and system reliability.

Abstract:The intermittent local loading forming method realized by dividing the whole die into several sub-dies provides a feasible way for the less-force integral forming of large aerospace closed-die forging.However,the lack of the matching forming equipment has limited the popularization and application of this process.Thus,in this study,an equipment structure for 10-tonne multi-pass local loading forming apparatus was designed.The designed local loading forming apparatus can provide 10-tonne forming load and 2-tonne constraint load,and thus can provide 20-tonne forming capacity.The finite element analyses of the stiffness,strength,and modal of the entire mechanical body for local loading forming apparatus were carried out.The results showed that the key components satisfied the design load,and the excitation source's operational frequency avoids the natural inherent frequencies of the whole structure.Then,a laboratory physical prototype was constructed.The relevant research provides the basis for further research on the design of large tonnage prototypes and industrial local loading forming equipment.

Abstract:To address the issues of poor weld quality and complex processes in traditional roll-welding methods for manufacturing vehicle-mounted liquefied natural gas(LNG)cylinders,this study proposes a novel counter-roller active spinning forming process and designs a dedicated full-electric servo spinning equipment.Based on analysis of process requirements for cylinder thinning and dome forming of LNG tanks,key technical parameters are established,including a maximum radial force of 300 kN and processing range of 600-800 mm.The equipment employs a vertical structural layout with innovative independent radial/axial feed systems for inner and outer spinning rollers.The spindle turntable is driven by three servo motors in coordination,while the outer roller assembly features dual-cone rollers and axial screw transmission.The inner roller achieves precision feeding through worm-gear and wedge mechanisms.Finite element analysis verifies critical components:The frame demonstrates maximum equivalent stress of 64.58 MPa with 0.174 mm deformation,and its six-order modal frequencies(8.42-30.48 Hz)remain distant from the operational frequency of 1.33 Hz.The inner roller support shows maximum stress of 192.21 MPa and radial deformation of 0.31 mm,both meeting the strength requirements of 45# steel.This integrated equipment combines cylinder thinning and dome forming capabilities,achieving seamless weld-free fabrication of LNG cylinders through coordinated control between active roller rotation and workpiece revolution.The design provides an innovative solution for manufacturing new energy fuel storage and transportation equipment.

Abstract:The stability of temperature control in the high-speed rolling process of high-speed bar production lines is crucial to the final product quality.To address the issues of slow dynamic response,significant disturbance influence,and limited temperature measurement accuracy in the thermal control system of the high-bar hot zone,this paper proposes an optimized control strategy that integrates Kalman filtering,PID control,and Particle Swarm Optimization(PSO).Firstly,the thermal dynamics of the steel bar are modeled as a second-order thermal inertia system,incorporating external disturbances and measurement noise to simulate actual industrial conditions.Subsequently,a Kalman filter is designed to estimate the system states and mitigate measurement noise,thereby enhancing feedback accuracy.On this basis,PSO is employed to globally optimize the PID controller parameters(Kp,Ki,Kd),aiming to achieve precise temperature regulation and disturbance rejection.Simulation results in Simulink demonstrate that the proposed control strategy effectively reduces steady-state error and overshoot,improves system robustness against external disturbances,and enhances response speed,providing theoretical support and engineering reference for the intelligent temperature control system of high-bar production lines.

Abstract:Surface defect detection of cold-rolled strips is crucial for industrial quality control.To address challenges including small defect omission,class imbalance,and low efficiency in ultra-high-resolution image processing,this study proposes Multi-scale Feature Adaptive Fusion-based Multi-task Segmentation Network(MFAFMSNet),an enhanced architecture integrating multi-scale context aggregation and attention-guided feature refinement.The method features:1)A residual network-based encoder with multi-dilation-rate spatial pyramid modules for cross-scale context fusion;2)A decoder incorporating multi-scale squeeze-and-excitation attention to enhance small defect detection;3)A multi-task framework with auxiliary defect classification to improve inter-class discrimination;4)A dynamic weighted hybrid Loss combining Dice and Focal Losses with adaptive weight adjustment for class imbalance mitigation.Experimental results on a constructed cold-rolled strip defect dataset show the model achieves state-of-the-art performance,with mIoU and Dice coefficients surpassing baseline models by 5.9％and 5.8％respectively.

Abstract:To address the sealing issue of an aircraft actuator,a two-dimensional axisymmetric simulation model of O-ring sealing under the combined effects of temperature and oil pressure was established using ANSYS software.The study systematically investigated the influence of backup ring presence,operating temperature,and O-ring diameter on contact pressure.The introduction of a backup ring increases the contact pressure of the O-ring,thereby preventing"extrusion"failure.Under the ultimate oil pressure of 27 MPa,the contact pressure of the O-ring at-55 ℃ operating environment is 1.9 MPa lower than that at room temperature.As the O-ring diameter increases,the contact pressure between the O-ring and the cover plate also rises.When the O-ring diameter is less than 1.50 mm,there exists a leakage risk at-55 ℃.The research findings provide theoretical guidance for the sealing design of O-rings.

Abstract:To solve the problems of low efficiency of hanging tag on the bundling wire of hot coiled bars in iron and steel enterprises and the problems of wrong hanging,missing hanging and dropping of tags caused by human operation,an intelligent hanging tag robot system on hot coiled bars based on binocular vision measurement was built.The hanging tag robot system is mainly composed of host computer communication control system,binocular vision recognition subsystem,preparation and supply subsystem of tag and pothook and automatic hanging tag subsystem.The host computer communication control system is the core of the whole robot system.The binocular vision recognition subsystem recognizes the wire rod and the bundling wire and obtains the pose of the hanging point.The preparation and supply subsystem of tag and pothook is divided into online tag preparation device and automatic pothook feeding device,both of which jointly complete on-line preparation of tag and pothook kit.The automatic hanging tag subsystem carries the camera,grabs the pothook and hangs the tag.The robot system prototype is built and the industrial field test is carried out.The hanging cycle is about 32 s.The test results show that the robot system has accurate recognition,stable work and good hanging effect,which can be used in the automatic hanging tag operation of hot coiled bars in iron and steel enterprises.