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Transverse Bending Characteristics in U-channel Forming of Tailor Rolled Blank

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Journal of Iron and Steel Research International 2016年第12期23卷 1249-1254页

作者： Hua-wei ZHANG ying-ping guan Jia-lu WU Xiang-hua LIU School of Control Engineering Northeastern University at Qinhuangdao College of Mechanical Engineering Yanshan University Research Institute of Science and Technology Northeastern University

Research on the formability of tailor rolled blank （TRB） is of good practical significance and application value because of the enormous potential of TRB in the aspect of automobile lightweight. However, the forming of TRB is problematic because of the varying properties; especially, springback is a main challenge. The transverse bending （bending axis is perpendicular to the rolling direction） of TRB U channel was studied through simulation and experiment. The forming characteristics of TRB U channel during transverse bending were analyzed. The mechanisms of forming defects, including bending springback and thickness transition zone （TTZ） movement, were revealed. On this basis, effects of blank geometric parameters on springbaek and TTZ movement were discussed. The results indicate that springback and TTZ movement happen during transverse bending of TRB U-channel. Nonuni form stress distribution is the most fundamental reason for the occurrence of springback of TRB during transverse bending. Annealing can eliminate nonuniform stress distribution, and thus diminish springbaek of TRB, especially springback on the thinner side. Therefore, springback of the whole TRB becomes more uniform. However, annealing can increase the TTZ movement. Blank thickness and TTZ position are the main factors affecting the formability of TRB U-channel during transverse bending.

关键词： tailor rolled blank transverse bending springback U-channel annealing thickness transition zone

Kinetic analysis of austenite transformation for B1500HS high-strength steel during continuous heating

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International Journal of Minerals,Metallurgy and Materials 2020年第11期27卷 1508-1516页

作者： Mu-yu Li Dan Yao Liu Yang Hao-ran Wang ying-ping guan Key Laboratory of Advanced Forging&Stamping Technology and Science(Ministry of Education of China) Yanshan UniversityQinhuangdao 066004China School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004China

The dilatometric curves of B1500HS high-strength steel at different heating rates were measured by a Gleeble-3800 thermal simulator and analyzed to investigate the effect of heating rate on *** show that the value of starting temperature and ending temperature of austenite transformation increase with the rise of heating rates,whereas the temperature interval of austenite formation *** kinetic equation of austenite transformation was solved using the Johnson–Mehl–Avrami model,and the related parameters of the equation were analyzed by the Kissinger *** those calculations,the activation energy of austenite transformation is 1.01×10^6 J/mol,and the values of kinetic parameters n and ln k0 are 0.63 and 103.03,*** relationship between the volume fraction of austenite and the heating time at different heating rates could be predicted using the kinetic *** predicted and experimental results were compared to verify the accuracy of the kinetic *** microstructure etched by different corrosive solutions was analyzed,and the reliability of kinetic equation was further verified from the microscopic perspective.

关键词： B1500HS high-strength steel dilatometric curve austenite transformation kinetic equation Johnson-Mehl-Avuami model

Characteristics of Precipitation in an As-cast Nb-and V-containing High Nitrogen CrMn Austenitic Steel

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Journal of Iron and Steel Research International 2014年第10期21卷 945-950页

作者： Zhong-ping SHI Zhen-hua WANG Shu-hua SUN Ze-an ZHOU ying-ping guan Wan-tang FU State Key Laboratory of Metastable Materials Science and Technology Yanshan University Key Laboratory of Advanced Forging and Stamping Technology and Science(Yanshan University) Ministry of Education of China

The phase diagram of an Nb- and V-containing 18Mnl8Cr0.5N steel was investigated using thermodynam ic calculation. The compositions and characteristics of precipitates were investigated by scanning electron microsco- py, energy dispersive spectrometry, X-ray diffraction, and differential scanning calorimetry. Under equilibrium con- ditions, MX precipitates at 1 350 ℃. MX is a substitutional solid solution of Nb4 N3.38, and its composition （at. %） is approximately.. Nb 40, N 40, V 8, and Fe, Cr, and Mn balance. The precipitates, with shapes including irregular bulk, rod, and ellipsoid, are primarily distributed at grain boundaries and triple junctions, and their size is approxi- mately 5 10 μm. Finally, the microalloying of high nitrogen CrMn austenite steels, control of precipitate size, and the effect of precipitate on hot formin~ were discussed.

关键词： high nitrogen steel microalloying precipitate

Mechanism and Inhibition of Grain Coarsening of Al-Mg-Si Alloy in Hot Forming

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Journal of Harbin Institute of Technology(New Series) 2013年第3期20卷 67-74页

作者： ying-ping guan Zhen-Hua Wang Bin Wu Wei-Xin Wang Wan-Tang Fu Key Laboratory of Advanced Forging & Stamping Technology and Science(Yanshan University) Ministry of Education of China College of Mechanical Engineering and Applied Electronic Technology Beijing University of Technology CITIC Dicastal Wheel Manufacturing Co. Ltd. State Key Laboratory of Metastable Materials Science and Technology Yanshan University

A high-Ti 6061 alloy was rolled with strains up to 0. 8 - 2. 0 and at 350 - 550 ℃ . Microstructures that developed during deformation and subsequent solution heat treatment (SHT) were observed by using optical and transmission electron microscopy. Microstructure evolution during SHT depends mainly on the initial rolling temperature,and it was found that the higher this temperature is,the coarser the grains are. After rolling at 400 ℃ ,well-defined cells and subgrains were formed, which induced further sites for recrystallization nucleation during subsequent SHT. The recrystallization mechanism was found to be subgrain rotation,with a final grain size smaller than 200 μm. Increasing the rolling temperature to 500 ℃ results in a low density of dislocations distributed uniformly in the deformed matrix and fewer nucleation sites during subsequent SHT. The recrystallization mechanism is grain boundary bulging,while the final grain size approaches several millimeters. Finally,a hot forming process of high-Ti 6061 alloy for inhibiting grain coarsening was proposed,and verified by experiments.

关键词： aluminum alloy grain size recrystallization nucleation mechanism

Theoretical prediction and experimental investigation on formability of tailor-welded blanks

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Transactions of Nonferrous Metals Society of China 2016年第1期26卷 228-236页

作者：马向东官英平燕山大学先进锻压成形技术与科学教育部重点实验室秦皇岛066004

Based on the elastoplastic mechanical properties of the weld and heat affected zone metals obtained by a nanoindentation test, a theoretical calculation model was established for the forming limit diagram（FLD） of tailor-welded blanks（TWBs） on the basis of plastic constitutive relations and Hosford yield criteria. Hemispherical punch bulging tests were performed to verify the FLD theoretical calculation results. The results demonstrated that not only the FLD theoretical calculation of base materials but also that of TWBs had a good agreement with their experiments. Besides, poorer formability of TWBs caused its FLD significantly lower than that of base materials. The theoretical calculation model offers a reliable approach to obtain the specific FLD of TWBs.

关键词： tailor-welded blank forming limit diagram nanoindentation test hemispherical punch bulging test

ZK61M高强镁合金板热变形过程中的韧性断裂预测

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Transactions of Nonferrous Metals Society of China 2023年第1期33卷 95-106页

作者：杨柳段永川官英平燕山大学先进锻压成形技术与科学教育部重点实验室秦皇岛066004 燕山大学机械工程学院秦皇岛066004

为了预测ZK61M高强镁合金板热变形过程的韧性断裂行为,在一定条件下进行实验和数值模拟。基于获得的各试件断口处的应力状态参数和断裂应变数据,采用粒子群优化算法求解4种断裂模型中的待定系数。依据误差评估结果,确定改进的Wilkins模... 详细信息

为了预测ZK61M高强镁合金板热变形过程的韧性断裂行为,在一定条件下进行实验和数值模拟。基于获得的各试件断口处的应力状态参数和断裂应变数据,采用粒子群优化算法求解4种断裂模型中的待定系数。依据误差评估结果,确定改进的Wilkins模型精度最高。将改进的Wilkins模型引入有限元中,并与实验进行对比。结果表明,预测的拉伸件断裂位移和断裂载荷的平均误差均小于15%,预测的圆筒形件成形深度的平均误差为13.88%,建立的有限元模型可以较为准确地模拟实验过程并预测断裂位置。

关键词： ZK61M板韧性断裂模型参数优化热变形圆筒形件

Roles and application of exosomes in the development,diagnosis and treatment of gastric cancer

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World Journal of Gastrointestinal Oncology 2024年第3期16卷 630-642页

作者： Xiao-Li guan Xiao-ying guan Zheng-Yi Zhang Department of General Medicine The Second Hospital of Lanzhou UniversityLanzhou 730030Gansu ProvinceChina Department of Pathology The Second Hospital of Lanzhou UniversityLanzhou 730030Gansu ProvinceChina

As important messengers of intercellular communication,exosomes can regulate local and distant cellular communication by transporting specific exosomal con-tents and can also promote or suppress the development and progression of gas-tric cancer(GC)by regulating the growth and proliferation of tumor cells,the tumor-related immune response and tumor *** transport bioactive molecules including DNA,proteins,and RNA(coding and noncoding)from donor cells to recipient cells,causing reprogramming of the target *** this review,we will describe how exosomes regulate the cellular immune respon-se,tumor angiogenesis,proliferation and metastasis of GC cells,and the role and mechanism of exosome-based therapy in human *** will also discuss the potential application value of exosomes as biomarkers in the diagnosis and treat-ment of GC and their relationship with drug resistance.

关键词： Exosomes Gastric cancer Immune regulation Diagnosis Cancer therapy

Flotation separation of scheelite from calcite using luteolin as a novel depressant

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 462-472页

作者： Xiaokang Li ying Zhang Haiyang He Yu Wu Danyu Wu Zhenhao guan Faculty of Land and Resources Engineering Kunming University of Science and TechnologyKunming 650093China State Key Laboratory of Clean Utilization of Complex Non-Ferrous Metal Resources Kunming University of Science and TechnologyKunming 650093China

This paper proposes luteolin(LUT)as a novel depressant for the flotation-based separation of scheelite and calcite in a sodium oleate(NaOL)*** suitability of LUT as a calcite depressant is confirmed through micro-flotation *** pH=9,with LUT concentration of 50 mg·L^(-1) and NaOL concentration of 50 mg·L^(-1),scheelite recovery reaches 80.3%.Calcite,on the other hand,exhibits a recovery rate of 17.6%,indicating a significant difference in floatability between the two ***,the surface modifica-tions of scheelite and calcite following LUT treatment are characterized using adsorption capacity testing,Zeta potential analysis,Fourier transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),and atomic force microscopy(AFM).The study in-vestigates the selective depressant mechanism of LUT on *** capacity testing and Zeta potential analysis demonstrate sub-stantial absorption of LUT on the surface of calcite,impeding the further adsorption of sodium oleate,while its impact on scheelite is ***-IR and XPS analyses reveal the selective adsorption of LUT onto the surface of calcite,forming strong chemisorption bonds between the hydroxyl group and calcium ions *** directly illustrates the distinct adsorption densities of LUT on the two miner-al ***,LUT can effectively serve as a depressant for calcite,enabling the successful separation of scheelite and calcite.

关键词： scheelite calcite luteolin flotation depressant separation

Stretchable and self-healing conductive fibers from hierarchical silver nanowires-assembled network

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Nano Research 2024年第2期17卷 763-770页

作者： ying-ying Wu Hong Chen Fan Zhang Pan Guo Haili Qin Huai-ping Cong Anhui Province Key Laboratory of Advanced Catalytic Materials and Reaction Engineering School of Chemistry and Chemical EngineeringHefei University of TechnologyHefei 230009China

Conductive fibers(CFs)with features of high conductivity,stretchability,self-healability,and electromechanical stability are key components of the increasingly popular wearable ***,since the lack of structural design of conductive network and interfacial interaction between soft polymer and conductive additives,it is still hard to enable CFs to meet above ***,we describe a facial drawing method from a hydrogel reservoir which is remolded into ultrathin and stretchable CFs with excellent multi-responsive *** hydrogel reservoir was fabricated in synergy of an ice-templating method and in situ polymerization using the assembled framework as a *** on the effective fabrication mechanism,the diameter of CFs could be well-tuned from 90 to 400μm by adjusting the dipping depth of the glass rod,accompanied with conductivity increased from 0.75 to 2.5 S/*** the hierarchical network structure was well maintained in the CFs,professional performances have been proved on the stretchability and electromechanical *** presence of massive hydrogen bonding and Ag–S bond enabled the CFs with excellent self-healability under the conditions of contact,electric field,and near infrared light,***,the CFs with high sensing property could be integrated into an advanced textile sensor through an effective healing-induced integration strategy,demonstrating its great potentials as superior two-dimensional(2D)electronic skins.

关键词： conductive fibers self-assembled silver nanowires Ag–S coordination self-healing flexible sensors