Abstract:To address the issue of SKP roll mark defects in the galvanizing line,this paper proposes a collaborative control method that deeply integrates data-driven approaches with process optimization.First,big data analysis was employed to quantify the correlation between prolonged production runs of exterior panels and the occurrence of roll marks.Subsequently,a deep neural network(DNN)-based model was developed to predict roll surface condition,enabling accurate early warnings of potential defects.Furthermore,an intelligent production rhythm optimization strategy,termed"periodic roll surface refreshing,"was introduced.A refined lifecycle management system for work rolls was also established,incorporating high-resolution scanning and progressive loading protocols.Application results demonstrate that the proposed method significantly reduces the rate of abnormal roll changes,thereby ensuring the stable production of high-grade exterior panels.This research presents a paradigm shift for quality control in rolling processes,moving from an"experience-driven"to a"data-and-intelligence-driven"approach.

Abstract:Vibration-induced fatigue failure in pipelines,which serve as critical fundamental components for fluid transport in heavy machinery and major technical equipment,presents a significant hazard to operational safety and stability.To enable accurate and efficient vibration assessment,existing criteria(such as the ASME OM3 standard)utilize a stress-velocity relationship.However,the higher-order modal correction factor(C5)within this relationship is difficult to obtain directly in engineering design and inspection,leading to a reliance on empirical values that lack conservative justification.To address this issue,this study performs a systematic modal analysis of single-span straight pipes based on the classic Euler-Bernoulli beam theory for structural vibration,combined with the traveling wave method.By conducting over fifty thousand parametric calculations covering variations in pipe length,diameter,wall thickness,and boundary constraints,the behavior of the C5 factor was investigated in depth.The results demonstrate that under the vast majority of working conditions,the C5value is highly concentrated around 1.0 and does not exceed a maximum of 1.11.Based on this statistical distribution,this paper proposes the unified adoption of a conservative value of C5=1.11 for the design and vibration assessment of pipelines in heavy equipment.This research provides a theoretical basis and data support for the vibration assessment and design optimization of pipeline components in major technical equipment,holding significant engineering value for enhancing equipment safety and reliability.

Abstract:In order to study the static load sharing characteristics of coaxial reversed herringbone gear transmission system,considering the factors such as transmission chain stiffness,alignment errors and manufacturing errors,the torque balance equation of the system is established,the deformation coordination condition of the system is deduced,and the influence of manufacturing and alignment errors on the load sharing performance of the system under single and combined action of gears is analyzed.The analysis shows that when there is a single error in Grade Ⅱ and Grade Ⅲ gears,the load sharing coefficient of the system shows an upward trend with increasing error,and the load sharing performance decreases gradually.When the system is under the comprehensive error,the gear Z8 has the greatest influence on the load sharing performance of the system,and the load sharing coefficient increases by 38.9％.Moreover,as the system speed increases,the load sharing performance gradually decreases.Therefore,In the design and manufacturing process of helicopter main reducer gears,the comprehensive error of gears should be strictly controlled to improve the load sharing performance of the system.

Abstract:A three-dimensional thermomechanical coupled finite element model was developed using Abaqus to address temperature non-uniformity and optimize process parameters synergistically in the roughing stage of a no-reheating direct rolling line for bars.The model enables a dynamic,strong-coupled simulation of the rolling force,temperature,and deformation fields.By employing adaptive mesh refinement,it quantitatively characterizes the fluctuations in rolling torque,the core-to-surface temperature gradient,and the velocity field distribution.This model provides a theoretical foundation for process optimization,effectively suppressing the end-temperature gradient induced by the direct rolling process and minimizing head-to-tail property variation within the same batch of products.

Abstract:Under the dual background of"ultra-low emission"and"double carbon",the iron and steel industry has put forward a new process to reduce pollution and carbon emissions in the treatment of sintering flue gas.The existing SCR denitrification reactor can be used to achieve catalytic synergistic removal of NOx and CO,but currently lacks efficient,stable,and adaptable dual-function catalysts for flue gas treatment.A series of m％CuCeOx/γ-Al2O3catalysts were designed by ultrasound-assisted isovolumetric impregnation method using γ-Al2O3 as the carrier and Cu-Ce composite oxides as the active component.The best performing catalysts were screened by optimization of loading and Cu:Ce molar ratio,and the NOx conversion was higher than 75％and CO conversion was higher than 99％at 200℃.The nature of Cu-Ce oxide loading on catalyst performance enhancement has been explored through various characterizations.On the one hand,Cu doping into the CeO2 lattice strengthens the interaction between Cu and Ce,resulting in the formation of richer oxygen vacancies in the composite oxide,which promotes the NOx reduction and CO oxidation reaction rates.On the other hand,Cu-Ce loading enhanced the number and strength of low-temperature acidic sites of the catalyst,which enhanced the SCR denitrification performance by promoting NH3 adsorption at low temperature.This study verified the feasibility of synergistic catalytic removal of NOx and CO from sintered flue gas and provided a new idea for the design of bifunctional catalysts.

Abstract:The flow characteristics of molten steel in the mold are one of the primary factors causing slab defects.Taking the 1 200 mm×135 mm slab continuous casting mold of a factory as the research object,a three-dimensional slab mold electromagnetic braking mathematical model was established,and the influence of electromagnetic braking installation position on the flow and heat transfer of molten steel in the mold was studied.The results show that when the center position of the electromagnetic brake is reduced from Z=270 mm to Z=470 mm,the velocity of the molten steel on the free surface of the mold decreases first and then increases,the impact depth of the molten steel in the mold gradually decreases,and the temperature field distribution of the central section of the mold gradually becomes symmetrical.When the electromagnetic brake position is too low,due to the unreasonable magnetic field distribution,the surface temperature distribution of the slab is not uniform,the temperature difference at the outlet of the narrow side of the mold increases,and the solidified shell is thinned.When the electromagnetic brake center position is Z=370 mm,the flow and heat transfer effect of molten steel in the slab mold is better,the maximum flow rate of the free surface center of the mold is 0.14 m/s,the solidification front of the slab is stable,and the solidification shell at the mold outlet is evenly distributed.

Abstract:12Cr1MoV steel is widely used in superheater tubes of subcritical and thermal power units,and is often used as the material for main steam pipes.Fatigue cracking at the welded joints is the main cause of their failure.To address the issue of local cracking at the welds under service loads,three-point bending tests and ABAQUS simulations were conducted on samples heat treated at 730℃and 660℃respectively.The research results show that compared with heat treatment at 730℃,isothermal treatment at 660℃is more likely to enhance the brittleness of the weld microstructure,causing cracking to occur preferentially at the fusion line.The research results are greatly significance for optimizing the welding process of 12Cr1MoV steel and preventing failure risks.

Abstract:To the demand for efficient and lightweight drive systems in large flapping wing aircraft,this paper proposes an optimized design scheme for an external rotor permanent magnet brushless motor.Based on the total weight of 20 kg and the power requirement of 200 W for the flapping wing aircraft,the key parameters of the motor were determined through classical motor theory calculations:using a 12 pole 16 slot combination,a surface mounted structure with neodymium iron boron permanent magnets,a rated power of 340 W,and a speed of 1 500 r/min.We focused on optimizing the stator slot parameters(hs0=2.5 mm,hs1=1 mm)and pole arc coefficient(0.7),and conducted electromagnetic simulation analysis using Maxwell software.The results showedthatafter optimization,the motor efficiency reached 88.6%,the rated torque was 10.5 N·m,the cogging torque was reduced to 0.867 N·m,and the distribution of unilateral magnetic pulling force was balanced.Finite element analysis verified the reasonable distribution of magnetic flux density(peak value 1.860 1 T)and the stability of back electromotive force waveform(25 V amplitude).This design provides a solution for flapping wing power systems that combines high power density and low vibration characteristics,and has significant engineering application value.

Abstract:Accurate characterization of the filter material as a porous medium is critical for computational fluid dynamics(CFD)simulations of bag filters.This study systematically evaluates two prevalent models—the porous jump model and the porous continuous model—to assess their applicability.The results show that both models predict a similar four-stage development of the internal transient flow(injection-entrainment,impact development,turbulent diffusion,and steady-state establishment)and agree on the overall trend of axial velocity along the filter bag.However,the porous continuous model demonstrates superior performance.By explicitly representing the porous layer thickness and incorporating the coupled effects of viscous and inertial resistance,it more accurately captures the flow rectification by the porous layer,the evolution of large-scale vortex structures,and the permeation of ambient fluid into the porous medium.Moreover,simulations using the porous continuous model reveal a pronounced longitudinal pressure gradient inside the filter bag,a feature not adequately captured by the jump model.Consequently,the porous continuous model provides a more realistic representation of the fluid-porous media interactions under practical conditions,yielding higher simulation accuracy and greater value for engineering applications.

Abstract:In response to the challenges of limited and imprecise measurement methods for radioactive liquid level and interface in nuclear fuel reprocessing,this paper presents the development of a split-type,radiation-resistant microwave level gauge based on time-domain extension technology.Through the innovative design of a triple-rod sensor,a split-type radiation-resistant structure,and a dual-echo recognition algorithm,high-precision simultaneous measurement of liquid level and interface has been achieved.Test results indicate that the instrument's measurement error is better than±5 mm,with key components enduring a cumulative radiation dose of up to 105 Gy,providing a reliable new measurement solution for extreme radioactive conditions.

Abstract:Laser cladding has established itself as a key technology in surface strengthening and remanufacturing,owing to its broad material selectivity,high bonding strength,and minimal heat-affected zone.However,the intrinsic rapid melting and solidification process often induces significant residual stress,leading to crack initiation and propagation within the coating,which severely limits its broader application.This paper provides a systematic review of the causes,suppression methods,and underlying mechanisms of cracks in laser-clad coatings.It begins with an in-depth analysis of crack origins from the perspectives of residual stress(comprising thermal stress,phase transformation stress,and constraint stress)and the matching of material physical properties.Subsequently,it elaborates on the operating mechanisms and research progress of various crack suppression strategies,including optimization of process parameters,addition of transition layers or rare earth elements,implementation of pre-heating and post-heat treatments,application of external auxiliary fields(e.g.,induction,electromagnetic,ultrasonic),and integration of in-situ process monitoring with numerical simulation.Finally,future development trends toward intelligentization and multi-field coupling are outlined.This review aims to furnish a theoretical basis and technical support for understanding the formation mechanisms,effective control,and suppression of cracks in laser-clad coatings.

Abstract:Ultrafine tungsten powder is a key raw material for high-performance tungsten-based products.However,most preparation methods remain confined to the laboratory scale,limited by low efficiency,operational safety risks,and high production costs.This review focuses on the hydrogen reduction of tungsten trioxide(WO3),analyzing its underlying reaction thermodynamics and kinetics.Preparation technologies are systematically categorized into two types based on the use of external reducing agents:"non-reducing agent participation"and"single reducing agent participation",with their fundamental principles,advantages,and disadvantages elaborated.Critical challenges—including difficulties in controlling particle size and morphology,hydrogen explosion risk,high energy consumption,and carbon contamination—are addressed,alongside proposed solutions such as process innovation,doping strategies,and atmosphere optimization.Finally,development directions toward greening and intelligentization are outlined to broaden the research perspective for large-scale production.

Abstract:To address the challenges faced by traditional hydraulic/mechanical mandrels in producing high-strength and thick strip steel,such as insufficient clamping force and hydraulic cylinder leakage,this paper innovatively designed a mechanically driven dual-jaw automatic lubrication mandrel.Firstly,the structure and working principle of this mandrel are specifically introduced,and the calculation methods for key parameters are provided.Subsequently,through practical engineering cases and finite element analysis,the rationality of the calculation methods and the superiority of the lubrication effect are verified.The mandrel structure adopts a dual-jaw design,effectively enhancing the clamping adaptability.On the one hand,it takes into account the convenience of operation;on the other hand,the problem of head deformation is successfully solved by optimizing the specifications of the disc spring.In addition,the optimized lubricant passage ensures uniform distribution of lubricating oil,achieving significant results in practical applications.

Abstract:Based on the crystal plasticity theory,this study systematically analyzed the plastic deformation,stress-strain distribution,and texture evolution process during the Pilger rolling forming process through numerical simulation technology,in order to obtain the deformation law of the refractory metal seamless tube rolling process and provide theoretical support for process optimization.Research shows that the stress concentration in the deformation zone of refractory metal seamless tubes during the initial stage of rolling directly reflects the drastic changes in mechanical behavior.As the number of rolling passes increases,the mechanical uniformity gradually improves,and the stress distribution stabilizes at the final sizing stage,fully demonstrating the close coupling relationship between the rolling deformation and the stress state.In terms of texture evolution,the large plastic deformation in the reducing zone causes grain rotation,resulting in a shift in the basal texture density.In the wall-thinning zone,grains further rotate and reorganize,and the crystal orientation gradually gains dominance.After the sizing and finishing in the sizing zone,the texture state stabilizes.This research not only provides quantitative references for optimizing the rolling process parameters and designing the die structure of refractory metal seamless tubes,but also offers an important basis and practical guidance for enhancing the performance of key tubes in high-end equipment manufacturing and other fields.

Abstract:The four-claw lifting clamp is a hoisting tool with strong operational flexibility and environmental adaptability,which has achieved excellent results in the thermal processing and manufacturing of large hydrogenation reactor cylinders.In order to grasp the stress state and strength information of the clamp arm during the lifting process,conducts a study on its stress state based on theoretical modeling and simulation analysis.Based on the working principle of the four-claw lifting clamp,its static equilibrium equation is established,and the stress theoretical equations of different cross-sections are derived,and the analytical calculation of stress state is achieved.On this basis,a finite element model of the clamp arm is established,and stress information of different cross-sections is obtained through simulation analysis.The results show that the average difference in stress values between the upper and lower surfaces of the clamp arm obtained from analytical calculation and simulation analysis is2.51%and2.86%,respectively,with high consistency.This indicates that the established stress theory equation can accurately reflect the surface stress state of the clamp arm,providing a theoretical basis for the design and strength verification of the four jaw clamp.

Abstract:Slant blades drum flying shear is an important equipment of stripe manufacturing,and its performance directly affects production efficiency and cutting quality.Through the analysis of the geometry characteristics of slant blades drum flying shear,it is found that the variation regularity of blades'gap on different sections of the drums.At the middle of drum,the gap value is relatively larger than the two sides of the drum.Such difference is much bigger when the overlap of top and bottom blades or the slant angle is increased.By establishing a mathematical model for the unfolding line of the cutting curve of blades,it is found that the unfold line is a triangle function curve,and the engagement length was calculated by the integration method.The research results indicate that increasing the slant angle of blade can reduce the engagement length and cutting force,but it can also lead to uneven distribution of blades'gaps,which can easily cause blades'biting.Reducing the overlap of blades can improve the uniformity of the blades'gap.This article provides a theoretical basis for the design and modification of the slant blades drum flying shear,which is an important guiding significance for solving the problems of blades wearing and cutting quality in practical production.

Abstract:Titanium/copper composite panels not only retain the high thermal and electrical conductivity of copper,but also possess the high strength and corrosion resistance of titanium.They are widely used in energy,aerospace,marine engineering and other fields.Among them,the Ti/Cu/Ti three-layer composite panel protects the copper layer with double-sided titanium layers,which can cope with the working conditions of double-sided corrosion resistance.Such as bipolar plates of fuel cells,anti-corrosion components in chemical equipment,etc.In this project,Ti/Cu/Ti composite plates were prepared by the hot rolling method.The influence of different rolling temperatures on the interfacial structure,microstructure and mechanical properties of the composite plates was explored.The variation laws of performance and structure of Ti/Cu/Ti composite plates at different rolling temperatures were revealed,obtaining the most suitable rolling process parameters,and the interface bonding mechanism was clarified,providing a process basis for the efficient preparation of high-performance Ti/Cu/Ti composite plates.

Abstract:In this study,through tensile testing of clad plates produced with different rolling processes,a theoretical model for the geometrically necessary dislocation stress and grain boundary misorientation in Q235 carbon steel substrate/304 stainless steel clad plates was developed.The relationship between geometrically necessary dislocation stress and grain boundary angles was subsequently calculated.The experimental results indicate that in the tensile sample with a 30%reduction rate,the fraction of low-angle grain boundaries(LAGBs)is33%,while that of high-angle grain boundaries(HAGBs)is 17.8%.For the sample with a 30%/20%reduction rate,the proportion of LAGBs in the carbon steel increased to 72%after tensile testing,while that of HAGBs decreased to 6.1%.When the reduction rate was raised to 35%/20%,the LAGBs further increased to 83%,and the HAGBs decreased to 5.3%.In the clad stainless steel of the same tensile samples,the proportions of LAGBs were measured to be 27%,75%,and 80%,while the corresponding proportions of HAGBs were 41.4%,15.2%,and 10.9%,respectively.As the number of rolling passes and the reduction rate increased,a portion of the high-angle grain boundaries(HAGBs)in the clad plate were transformed into low-angle grain boundaries(LAGBs).

Abstract:By analyzing the equipment and process characteristics of the RH refining furnace feeding system,process and control optimizations were implemented to address the issue of sequential execution delays between batches during multi-batch material addition.Each material batch was horizontally divided into material units and control units.Along the vertical dimension of the equipment execution process,various buffer points were designed to function as multi-batch temporary storage and batch synchronization zones.A data-driven intelligent unit,based on real-time material and equipment status,was established to achieve online asynchronous and partitioned execution of multi-batch materials.As a result,overall feeding time was reduced,processing cycles were shortened,and production efficiency was improved,achieving good application results.

Abstract:To address the limitations of current remaining useful life(RUL)prediction models for rolling bearings in long-sequence feature extraction and model generalization capability,this paper proposes a remaining life prediction method based on Temporal Convolution Network(TCN),SimAM module,and Bi-directional Gated Recurrent Unit(BiGRU).Firstly,TCN is used for short-term feature extraction,and its dilated convolutions and residual structures are utilized to efficiently model the input sequence.Subsequently,the SimAM module adaptively weights the extracted features to suppress redundant information and enhance key feature representation.Finally,a BiGRU is utilized to capture long-term dependencies within the input sequences by integrating forward and backward information,thereby improving the modeling capability for complex data.The proposed method was validated using the IEEE PHM 2012 dataset.Results demonstrate that it significantly improves both the accuracy of long-sequence prediction and its adaptability to various operating conditions.