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Banded structure control of low carbon microalloyed steel based on oxide metallurgy

Journal of Iron and Steel Research(International) 2023年第11期30卷 2242-2253页

作者： Yong-kun yang Jia-yu Zhu Xiao-ming Li yang Wang Dong-ping Zhan School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an710055ShaanxiChina School of Metallurgy Northeastern UniversityShenyang110819LiaoningChina

Banded structure is a common harmful microstructure for low carbon microalloyed steel,which seriously shortens the service life of processed parts.In order to study the effect of oxide metallurgy on improving banded structure,the Ti-Zr deoxidized low carbon microalloyed steel that can play the oxide metallurgical role of inclusion was chosen as the research object,and the inclusion characteristics,microstructure and transverse and longitudinal mechanical properties after hot rolling were analyzed.The results showed the inclusion number density increased in all experimental steels after hot rolling,and a large number of long strip inclusions with aspect ratio greater than 3 appeared along the rolling direction.In addition,after hot rolling,there were element segregation bands in the experimental steels,and granular bainite bands were formed in the element enrichment zone.However,the intragranular ferrite generated in the cooling process destroyed the continuity of granular bainite bands,so that the microstructure anisotropy indexes of experimental steels were small.The mechanical properties analysis showed that the anisotropy of performance was mainly reflected in plasticity and toughness in the experimental steels.Among them,the difference ratio of elongation,section shrinkage and impact energy of No.2 steel was 1.69%,3.87% and 1.69%,respectively,which were less than those of No.1 steel and No.3 steel.The anisotropy of microstructure and mechanical properties of No.2 steel that full played the role of oxide metallurgy were improved,and the banded structure control of low carbon microalloyed steel can be realized by oxide metallurgy technology.

关键词： Low carbon microalloyed steel Hot rolling Banded structure Oxide metallurgy Intragranular ferrite

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Evolution of inclusion and microstructure in Ti-Zr deoxidized steel during hot compression

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Journal of Iron and Steel Research(International) 2023年第10期30卷 1987-1999页

作者： Yong-kun yang Jia-yu Zhu Xiao-ming Li yang Wang Cheng-jun Liu Dong-ping Zhan School of Metallurgical Engineering Xi'an University of Architecture and TechnologyXi'an 710055ShaanxiChina Key Laboratory for Ecological Metallurgy of Multimetallic Mineral(Ministry of Education) Northeastern UniversityShenyang 110819LiaoningChina School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina

The effects of different hot deformation amounts on the evolution of inclusion and microstructure in Ti-Zr deoxidized steel were studied by utilizing the Thermecmaster-Z hot simulation test machine,automatic scanning electron microscope equipped with energy-dispersive spectrometer,and electron backscattered diffraction.The results indicated that hot deformation amount has no significant effect on the number density of oxide,but the MnS that precipitated on the Ti-Zr oxide surface undergoes extension and breakage,resulting in the changes in oxide aspect ratio.Moreover,the fracture of nitride mainly occurs in the sample with the second pass deformation amount of 42.9%and 71.4%,and the degree of fragmentation of nitride is more serious with the deformation amount increasing.During the hot compression,sulfide undergoes breakage and extension,and with the second pass deformation amount increasing,the breakage and extension of sulfide present a periodic change.Finally,with the increase in hot compression amount,the ferrite types in microstructure change from acicular ferrite and bainitic ferrite to polygonal ferrite,and the ferrite grain size is refined.When the total deformation amount increases from 30%to 80%,the ferrite grain sizes of grain boundary with the misorientation of 4°and 15°decrease from 4.14 and 5.67μm to 3.47 and 4.40μm,respectively.However,when the total deformation amount increases to 80%,the harmful ferrite/pearlite banded structure appears in the micro structure.Refining ferrite grain size and avoiding harmful microstructure are the key for the optimization of hot compression process.

关键词： Hot compression Oxide Nitride Sulfide Microstructure Grain size Ti-Zr deoxidized steel

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Experimental study of surfactant-enhanced spontaneous imbibition in fractured tight sandstone reservoirs: The effect of fracture distribution

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Petroleum Science 2023年第1期20卷 370-381页

作者： kun yang Fu-yong Wang Jiu-Yu Zhao State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing102249P.R.China College of Petroleum Engineering China University of Petroleum(Beijing)Beijing102249P.R.China College of Artificial Intelligence China University of Petroleum(Beijing)Beijing102249P.R.China College of Geosciences China University of Petroleum(Beijing)Beijing102249P.R.China

Spontaneous imbibition is an important phenomenon in tight reservoirs.The existence of a large number of fractures and micro-nano pores is the key factor affecting the spontaneous imbibition of tight reservoirs.In this study,based on high-pressure mercury injection and nuclear magnetic resonance experiments,the pore distribution of tight sandstone is described.The influence of fractures,core porosity and permeability,and surfactants on the spontaneous imbibition of tight sandstone are studied by physical fracturing,interfacial tension test,wettability test and imbibition experiments.The results show that:the pore radius of tight sandstone is concentrated in 0.01-1 mm.Fractures can effectively reduce the oil drop adsorption on the core surface,enhancing the imbibition recovery of the tight sandstone with an increase of about 10%.As the number of fractures increases,the number of oil droplets adsorbed on the core surface decrease and the imbibition rate increases.The imbibition recovery increases with the increase in pore connectivity,while the imbibition rate increases with the increases in core porosity and permeability.The surfactant can improve the core water wettability and reduce the oilwater interfacial tension,reducing the adsorption of oil droplets on the core surface,and improving the core imbibition recovery with an increase of about 15%.In a word,the existence of fractures and surfactants can enhance the pore connectivity of the reservoir,reduce the adsorption of oil droplets on the core surface,and improve the imbibition rate and recovery rate of the tight oil reservoir.

关键词： Tight sandstone Imbibition Fracture Surfactant

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A review of research on central crack in continuous casting strand

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Journal of Iron and Steel Research(International) 2023年第6期30卷 1073-1089页

作者： Yong-kun yang Jia-yu Zhu Wei-an Wang yang Wang Jian-li Wang Guan-jie Wang Xiao-ming Li School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055ShaanxiChina

Central crack is a common quality defect in continuous casting strand,which is difficult to fully weld in the rolling and forging processes,and has become a key technical problem that restricts the stable production of high-end alloy rod/forging/pipe.In recent years,the central crack control has been one of the main focuses in high quality steel research.In order to fully understand the central crack,the research status of central crack characteristics,formation mechanism,influencing factors,and control methods in the world was reviewed.The deficiencies in the research of the central crack and the key research directions in the future were pointed out,which will provide references for other scholars in this field of research.It is found that alloying elements segregation during solidification and inclusions precipitated at grain boundaries are the main reasons for the central crack formation,while the unreasonable application of production processes can also induce the initiation of central crack.The optimization of alloying element composition and production process is helpful to reduce the initiation of central cracks.In addition,the quantitative characterization mechanism based on steel grades,temperature,stress,and other factors induced central crack should be established in the further study,forming a systematic quantitative determination criterion and control strategy for coupling the composition,process and thermal/mechanical characteristic.

关键词： Central crack Continuous casting strand Formation mechanism Alloying element Control strategy

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Diagnosis and treatment of 2019 novel coronavirus infection in children: a pressing issue

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World Journal of Pediatrics 2020年第3期16卷 219-221页

作者： kun-Ling Shen yong-Hong yang China National Clinical Research Center for Respiratory Diseases BeijingChina Department of Respiratory Medicine Beijing Children's HospitalCapital Medical UniversityBeijingChina National Center for Children's Health BeijingChina Beijing Pediatric Reasearch Institute BeijingChina

The viral pneumonia in Wuhan City,China has spread around China.The virus has been proven to be a novel coronavirus (named as "2019-nCoV") by World Health Organization (WHO).2019-nCoV belongs to beta-coronavirus genera.On January 30,2020,WHO re-evaluated the potential effects of 2019-nCoV infection in global public health,and declared this epidemic as a "Public Health Emergency of International Concern (PHEIC)".

关键词： China. treatment belongs

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Porous polyurethane hydrogels incorporated with CMC for eliminating methylene blue from water

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International Journal of Smart and Nano Materials 2023年第1期14卷 57-76页

作者： Li Wang Qing yang yong yang kun Luo Ruqing Bai Peicong Zhang Department of Biomedical Engineering School of Big Health and Intelligent EngineeringChengdu Medical CollegeChengduChina College of Materials Chemistry&Chemical EngineeringChengdu University of TechnologySichuanP.R.China State Key Laboratory of Mechanical Transmission Chongqing University400044ChongqingChina College of Materials Chemistry&Chemical EngineeringChengdu University of Technology610059SichuanP.R.China

Here,a series of polyurethane porous hydrogels(PUF-s)loaded with different sodium carboxymethyl cellulose(CMC)were successfully prepared by one-step foaming method.The physio-chemical prop-erties and morphologies were characterized.The effects of CMC content,adsorbent dosage,temperature,pH value and other fac-tors on the adsorption of methylene blue(MB)dye in water by CMC-PUF-s were also investigated through static adsorption experi-ments.The results showed that CMC-PUF-10 had excellent adsorp-tion performance for MB solution with removal rate of 81.47%,and the maximum adsorption capacity was 27.5 mg/g.In addition,the study of adsorption kinetics and adsorption isotherms showed that the adsorption of MB by CMC-PUF was more consistent with Langmuir isotherm adsorption model and pseudo second-order kinetic model.The adsorption thermodynamics study suggested that the adsorption process of MB by CMC-PUF-10 was sponta-neous and exothermic at room temperature.The results of cyclic adsorption experiment demonstrated that the removal rate of MB reached above 70%after five cycles,indicating the foams with excellent recyclability.Finally,a low-cost,environmentally friendly and recyclable MB adsorbent was synthesized in this study.As polyurethane foam was synthesized by one-step foaming method,this adsorbent can be prepared on site in practical application and reduce the transportation cost.

关键词： Carboxymethyl cellulose polyurethane foam hydrogel methylene blue adsorption

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Review on regulation of MnS in non-qquenched and tempered steel

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Journal of Iron and Steel Research(International) 2024年第4期31卷 779-789页

作者： Guo-xing Qiu Qing Du Feng Lu De-jun Miao Yong-kun yang Xiao-ming Li School of Metallurgical Engineering Xi'an University of Architecture and TechnologyXi'an 710055ShaanxiChina Laigang Technique Center Shandong Iron and Steel Group Co.Ltd.Jinan 271104ShandongChina

An overview of the current research status and control methods of MnS in non-quenched and tempered steel was provided.As a low-melting plastic inclusion,the morphology and distribution of MnS were influenced by various production processes.Therefore,control of MnS is a systematic problem that must be integrated into the entire production process.Based on the production process,the factors affecting the morphology and distribution of MnS in steel were introduced.The effects of oxygen activity,manganese,sulfur,and some alloys on MnS inclusion precipitation were summarized,mainly including MnS modification treatment and oxygen-sulfide composite precipitation control.It is believed that MnS precipitates during the solidification process of steel,and controlling the solidification cooling rate could effectively regulate the size and morphology of MnS,avoiding the precipitation of II-MnS.Additionally,by changing the deformation rate,deformation amount,deformation temperature during the hot deformation process,and heating time and temperature during heat treatment,the distribution and morphology of MnS could be improved.Through the fine control of the above process parameters,the number of II-MnS in steel could be effectively reduced,and their morphology could be improved,thereby enhancing the performance of non-quenched and tempered steel and promoting its wider application.Furthermore,applying laboratory research results to industrial production is an important direction for future research efforts in this field.

关键词： MnS Non-quenched and tempered steel Control technology Process parameter Morphology Distribution

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Micro-/nanostructured ZnFe_(2)O_(4) hollow sphere/GO composite for structurally enhanced photocatalysis performance

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Rare Metals 2023年第3期42卷 813-821页

作者： yang-yang Zhao Xian-Biao Wang Qian-kun Xu Soufian Chakir yong-Fei Xu Bao Xu yong-Hua Hu Anhui Province International Research Center on Advanced Building Materials School of Materials Science and Chemical EngineeringAnhui Jianzhu UniversityHefei 230601China Institute of Solid State Physics Chinese Academy of SciencesHefei 230031China Anhui Institute of Building Science Research and Design Hefei 230031China Anhui Key Laboratory of Tobacco Chemistry Hefei 230088China

The pollution of organic dyes has become a serious environmental problem.It is still urgent to prepare a highly efficient and environment-friendly photocatalyst for pollutants removal.Herein,a micro-/nanostructured ZnFe_(2)O_(4)hollow sphere/GO(ZnFe_(2)O_(4)/GO)composite photocatalyst was prepared through a one-step hydrothermal method with high performance and recycling property.The obtained micro-/nanostructured composite was assembled by ZnFe_(2)O_(4) hollow spheres and GO nanosheets.

关键词： composite property performance

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Computer Navigation-aided Resection of Sacral Chordomas

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Chinese Medical Journal 2016年第2期129卷 162-168页

作者： Yong-kun yang Chung-Ming Chan Qing Zhang Hai-Rong Xu Xiao-Hui Niu Department of Orthopedic Oncology Surgery Beijing Ji Shui Tan Hospital Peking University Beijing 100035 China Department of Orthopaedics and Rehabilitation Division of Musculoskeletal Oncology University of Florida Gainesville Florida 32611 USA

Background： Resection of sacral chordomas is challenging. The anatomy is complex, and there are often no bony landmarks to guide the resection. Achieving adequate surgical margins is, therefore, difficult, and the recurrence rate is high. Use of computer navigation may allow optimal preoperative planning and improve precision in tumor resection. The purpose of this study was to evaluate the safety and feasibility of computer navigation-aided resection of sacral chordomas. Methods： Between 2007 and 2013, a total of 26 patients with sacral chordoma underwent computer navigation-aided surgery were included and followed for a minimum of 18 months. There were 21 primary cases and 5 recurrent cases, with a mean age of 55.8 years old （range： 35 84 years old）. Tumors were located above the level of the $3 neural foramen in 23 patients and below the level of the $3 neural foramen in 3 patients. Three-dimensional images were reconstructed with a computed tomography-based navigation system combined with the magnetic resonance images using the navigation software. Tumors were resected via a posterior approach assisted by the computer navigation. Mean follow-up was 38.6 months （range： 18-84 months）. Results： Mean operative time was 307 min. Mean intraoperative blood loss was 3065 ml. For computer navigation, the mean registration deviation during surgery was 1.7 ram. There were 18 wide resections, 4 marginal resections, and 4 intralesional resections. All patients were alive at the final follow-up, with 2 （7.7%） exhibiting tumor recurrence. The other 24 patients were tumor-free. The mean Musculoskeletal Tumor Society Score was 27.3 （range： 19-30）. Conclusions： Computer-assisted navigation can be safely applied to the resection of the sacral chordomas, allowing execution of preoperative plans, and achieving good oncological outcomes. Nevertheless, this needs to be accomplished by surgeons with adequate experience and skill.

关键词： Chordoma Computer-assisted Navigation Resection Sacral

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Towards autonomous and optimal excavation of shield machine:a deep reinforcement learning-based approach

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2022年第6期23卷 458-478页

作者： Ya-kun ZHANG Guo-fang GONG Hua-yong yang Yu-xi CHEN Geng-lin CHEN State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310027China School of Electrical and Power Engineering China University of Mining and TechnologyXuzhou 221116China

Autonomous excavation operation is a major trend in the development of a new generation of intelligent tunnel boring machines(TBMs).However,existing technologies are limited to supervised machine learning and static optimization,which cannot outperform human operation and deal with ever changing geological conditions and the long-term performance measure.The aim of this study is to resolve the problem of dynamic optimization of the shield excavation performance,as well as to achieve autonomous optimal excavation.In this study,a novel autonomous optimal excavation approach that integrates deep reinforcement learning and optimal control is proposed for shield machines.Based on a first-principles analysis of the machine-ground interaction dynamics of the excavation process,a deep neural network model is developed using construction field data consisting of 1.1 million samples.The multi-system coupling mechanism is revealed by establishing an overall system model.Based on the overall system analysis,the autonomous optimal excavation problem is decomposed into a multi-objective dynamic optimization problem and an optimal control problem.Subsequently,a dimensionless multi-objective comprehensive excavation performance measure is proposed.A deep reinforcement learning method is used to solve for the optimal action sequence trajectory,and optimal closed-loop feedback controllers are designed to achieve accurate execution.The performance of the proposed approach is compared to that of human operation by using the construction field data.The simulation results show that the proposed approach not only has the potential to replace human operation but also can significantly improve the comprehensive excavation performance.

关键词： Shield machine Slurry shield Intelligent tunnel boring machine(TBM) Deep reinforcement learning Optimal control Dynamic optimization Deep learning

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