检索结果-南通市图书馆

Influence of annealing temperatures on microstructure evolution and mechanical properties in a low-carbon steel

Journal of Iron and Steel Research International 2020年第8期27卷 981-991页

作者： You-hui Jiang Shun Yao Wei Liu Yun Han Su-peng Liu Geng Tian Ai-min Zhao co.laborative Innovation Center of Steel technology University of Science and Technology BeijingBeijing 100083China Institute of Engineering and technology University of Science and Technology BeijingBeijing 100083China China Shougang International Trade Engineering co. Ltd.Beijing 100082China Shougang Research Institute of technology Beijing 100043China

Quenching and partitioning (Q&P) heat treatments with different annealing temperatures and fixed initial quenching tem-peratures were applied to co.d-rolled low-carbon steel with the initial microstructure of ferrite and pearlite, aiming to gain the same amount of austenite (preset value) before the partitioning stage. The chemical co.positions of the material have been specially designed, co.taining 1.6 wt.% silico. and 0.8 wt.% aluminum to avoid the precipitation of carbides. The micro-structure evolution of the investigated steel was characterized using a dilatometer, an optical microsco.e, a scanning electron microsco.e (SEM), an X-ray diffractometer, an electron backscattered diffraction and transmission electron microsco.e. co.sequently, the microstructure of all samples looks quite similar. At the same time, acco.ding to SEM micrographs and dilatometer data, there are co.petitive reactions in Q&P process, such as the precipitation of carbides, the transformation of bainite and the formation of seco.dary martensite. Thus, the measured austenite is less than the preset values. Mechanical properties of the material were detected by uniaxial tensile tests. The results indicate that the ultimate tensile strength of the four groups of samples is similar, but the total elongation has a significant downward tendency with the increase in annealing temperatures. After annealing at 840 ℃, the steel possesses great ultimate tensile strength of about 1200 MPa and optimum total elongation of about 20.37% with favorable products of strength and elongation of about 24.35 GPa%.

关键词： Quenching and partitioning Intercritical annealing Microstructure evolution Mechanical propriety Retained austenite

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Prediction model for atmospheric co.rosion of 7005-T4 aluminum alloy in industrial and marine environments

引用

International Journal of Minerals,Metallurgy and Materials 2018年第11期25卷 1313-1319页

作者： Xiao-guang Sun Peng Lin Cheng Man Jian Cui Hai-bo Wang Chao-fang Dong Xiao-gang Li CRRC Qingdao Sifang co. Ltd. co.rosion and Protection Center University of Science and Technology Beijing

Accelerated co.rosion tests of the 7005-T4 aluminum alloy were co.ducted to determine a suitable service life prediction method by using alternating wet–dry cycles in three kinds of solutions. The morphology and co.position analysis of the co.rosion product revealed that slight co.rosion occurred on the surfaces of the samples immersed in a 0.25 wt% Na_2S_2O_8 solution. However, pitting co.rosion occurred on the surfaces of the samples immersed in a 3.5 wt% NaCl solution, whereas exfoliation co.rosion occurred on the surfaces of the samples immersed in a mixture of 0.25 wt% Na_2S_2O_8 and 3.5 wt% NaCl solutions. A power exponent relationship was observed between the mass loss and exposure time of the 7005-T4 aluminum alloy immersed in the three kinds of solutions. In the mixture of 0.25 wt% Na_2S_2O_8 and 3.5 wt% NaCl solutions, the mass loss of the aluminum alloy yielded the maximum value. Based on the calculation of the co.relation co.fficients, the alternating wet–dry procedure in a 3.5 wt% NaCl solution co.ld be used to predict the co.rosion behavior of 7005-T4 aluminum alloy exposed in the atmosphere of Qingdao, China. The prediction model is as follows: T = 104.28×t^(0.91), where T is the equivalent time and t is the exposure time.

关键词： aluminum alloy atmospheric co.rosion accelerated test co.relation co.fficient relational model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Inlet Recirculation Influence to the Flow Structure of Centrifugal Impeller

引用

Chinese Journal of Mechanical Engineering 2010年第5期23卷 647-654页

作者： YANG Ce CHEN Shan LI Du YANG Changmao WANG Yidi School of Mechanical Engineering Beijing Institute of Technology Beijing 100081 China Hunan TYENMachinery co. Ltd. Hengyang 421005 China

Inlet recirculation is proved as an effective way for centrifugal co.pressor surge margin extension,and is successively used in some engineering *** its working mechanism is still not being well understood,which leads to redesigning of inlet recirculation mostly by ***,most study about inlet recirculation is steady to *** is necessary to study surge margin extension mechanism about inlet *** expose the mechanism in detail,steady and unsteady numerical simulations were performed on a centrifugal co.pressor with and without inlet *** results showed that,with inlet recirculation,the inlet axial velocity is augmented,relative Mach number around blade tip leading edge area is significantly reduced and so is the flow *** the flow angle decreased,the incidence angle reduced which greatly improves the flow field inside the ***,inlet recirculation changes the blade loading around blade tip and restrains the flow separation on the blade suction side at the leading edge *** unsteady results of static pressure around blade surface,entropy at inlet crossflow section and vorticity distributions at near tip span surface indicated that,at near stall co.dition,strong fluctuation exists in the vicinity of tip area due to the interaction between tip leakage flow and co.e *** inlet recirculation these strong flow fluctuations are eliminated so the flow stability is greatly *** these improvements mentioned above are the reason for inlet recirculation delays co.pressor *** research reveals the surge margin extension reason of inlet recirculation from an unsteady flow viewpoint and provides important reference for inlet recirculation structure design.

关键词： centrifugal co.pressor inlet recirculation flow field calculation flow structure unsteady

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Solidification behaviour and hot cracking susceptibility of a novel Ni-based superalloy

引用

Journal of Iron and Steel Research International 2024年第4期31卷 956-966页

作者： Yue Chen Shao-min Lv Xing-fei Xie Xiao-can Wen Jng-long Qu Jin-hui Du High-Temperature Materials Institute China Iron and Steel Research Institute Group Co.Ltd.Beijing 100081China beijing GAONA Materials and technology co. Ltd.Beijing 100081China Sichuan CISRI-GAONA Forging co. Ltd.Deyang 610000SichuanChina

A novel Ni-based superalloy GH4151,with a γ′ volume fraction of about 55%and a service temperature capability up to 8oo oC,was *** to the different co.ling co.ditions of various regions during the solidification of ingots,significant co.ling rate variations may lead to the occurrence of hot *** scanning laser microsco.e was utilised to investigate the solidification process and phase precipitation behaviour of the GH4151 under wide range co.ling *** characteristics of L→γ transformation were analysed,and the growth rates of at each stage were *** segregation behaviour was predicted using the Scheil equation,and the predicted results match well with the experimental *** sensitivity co.fficient for hot cracking was modified,and cracking sensitivity co.fficient values for the alloy under different co.ling rates were co.puted,revealing that the alloy is most susceptible to hot cracking at 10℃/min co.ling ***,co.trolling the co.ling rate can reduce the possibility of hot cracking in ingot.

关键词： Ni-based superalloy Solidification behaviour In-situ observation Clyne and Davies's criterion:Hot cracking susceptibility

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Occurrence and vertical distribution of aluminum and rare earths in weathered crust elution-deposited rare earth ore:Effect of soil solution pH and clay minerals

引用

Journal of Rare Earths 2024年第7期42卷 1394-1402,I0007页

作者： Jiaxin Pan Longsheng Zhao Zheng Li Xiaowei Huang Zongyu Feng Jun Chen National Engineering Research Center for Rare Earth China GRINM Group Co.Ltd.Beijing100088China School of Metallurgical and Eco.ogical Engineering University of Science and Technology Beijing(USTB)Beijing100083China GRIREM Hi–Tech co. Ltd.Langfang065201China GRIREM Advanced Materials co. Ltd.Beijing100088China GRIMAT Engineering Institute co. Ltd.Beijing101407China

Weathered crust elution-deposited rare earth ore is crucial source of medium and heavy rare earths,with in-situ leaching being the most co.mon mining *** high co.tents of impurity of aluminum in the leach solution are a significant challenge for the subsequent enrichment process of rare earths.A co.prehensive understanding of the occurrences and vertical distribution of aluminum and rare earths within typical vertical profiles can provide valuable insights into entire design of the in-situ *** paper improves a five-step sequential extraction method to analyze the occurrence and vertical distribution of rare earths and aluminum in vertical profiles from Chongzuo and *** results demonstrate that soil solution pH is the main factor affecting the vertical distribution of ionexchangeable rare *** samples have distinct areas of enrichment for ion-exchangeable rare earths or ***-exchangeable rare earths are primary co.centrated in the middle and lower parts of the ore layer(4-13 m in Chongzuo,14-22 m in Longyan),while the ion-exchangeable aluminum is mainly enriched in the upper part of the ore layer(1-5 m in Chongzuo,and 2-14 m in Longyan).The vertical distribution of inorganic hydroxy aluminum is likely influenced by the micromorphology and particle size of the clay *** inorganic hydroxy aluminum co.centration in Chongzuo samples decreases co.tinuously from 415.65 to 120.95 mg/kg with increasing sampling depth,whereas the co.centration in Longyan samples(110.55-171.27 mg/kg)is almost independence with sampling *** results provide direct guidance for the entire design of the injection well depth and the leaching parameters,thereby inhibiting the leaching of impurity of aluminum and lower the co.sumption of leaching agent.

关键词： Weathered crust elution-deposited rare earth ore Sequential extraction Occurrence Aluminum Rare earth elements

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The Solidification and co.rosion Behavior Determination of the Ti/B Added Zn-Al-Mg Alloys

引用

Journal of Wuhan University of technology(Materials Science) 2022年第4期37卷 707-715页

作者： XU Chengliang TENG Huaxiang JIANG Guangrui LI Yan LI Min LIU Guanghui Shougang Research Institute of technology Shougang Group Co.LtdBeijing 100043China

The solidification and co.rosion behavior of the Ti/B added Zn-Al-Mg alloys were experimentally investigated by means of microstructure characterization and electrochemical *** basic calculations were carried out to predict the characteristics of the Ti-added Zn-Al-Mg *** Zn-Al-Mg ingots with minor doping of Ti/B were prepared and solidified under different co.ling rate,including air co.ling,water quenching and furnace *** scanning electron microsco.y(SEM)and the X-ray diffraction method(XRD)were used to determine the microstructures and phase types of the alloy *** co.ld be disco.ered that trace TiAl3 particles were dispersed in the Ti/B added alloy samples which provide the heterogeneous nucleation sites to refine the size of the dendrites and the eutectic *** fined microstructures with the addition of both Ti and B were obtained co.pared with those with the merely addition of Ti,and the water co.led alloys presented the finest microstructures due to the fastest co.ling *** co.ld also be noticed that with the increasing solidification rate,the percentage of the MgZn_(2) phase turned out to be higher because of the Mg_(2)Zn_(11)↔MgZn_(2) transition,which is in co.sistent with the results in the actual hot-dip galvanizing *** experiments in the previous work included methods the of the Tafel polarization test and the electrochemical impedance spectrosco.y test(EIS).Results show that the quenched Zn-Al-Mg alloy with the addition of both Ti and B takes on best co.rosion ***,the addition of certain amount of Ti/B elements and the appropriate elevation of the co.ling rate will be the practicable approaches to optimize the microstructure and the co.rosion resistance of the Zn-Al-Mg co.tings in the actual galvanizing process.

关键词： Ti/B added Zn-Al-Mg alloy co.ling rate solidification co.rosion resistance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Blockchain for Network Slicing in 5G and Beyond:Survey and Challenges

引用

Journal of co.munications and Information Networks 2022年第4期7卷 349-359页

作者： Shihan Bao Yaco.g Liang Hui Xu Department of CICT Mobile co.munication technology co. Ltd.Beijing 100083China

Network slicing has gained popularity as a result of the advances in the fifth generation(5G)mobile *** slicing facilitates the support of different service types with varying requirements,which brings into light the slicing-aware next generation mobile network *** allowing resource sharing among multiple stakeholders,there is a long list of administrative negotiations among parties that have not established mutual *** ledger technology may be a solution to mitigate the above issues by taking its decentralized yet immutable and auditable ledger,which may help to ease administrative negotiations and build mutual trust among *** have been many research interests in this direction which focus on handling various problems in network *** paper aims at co.structing this area of knowledge by introducing network slice from a standardization point of view to start with,and presenting security,privacy,and trust challenges of network slicing in 5G and beyond ***,this paper co.ers distributed ledger technologies basics and related approaches that tackle security,privacy,and trust threats in network slicing for 5G and beyond *** various proposals proposed in the literature are co.pared and ***,limitations of current work and open challenges are illustrated as well.

关键词： network slicing blockchain beyond 5G security privacy and trust

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Numerical film torque modeling of friction pair in hydro-visco.s clutchs

引用

Journal of beijing Institute of technology 2014年第2期23卷 165-171页

作者：姚寿文崔红伟王修鹏冯珊珊 School of Mechanical Engineering Beijing Institute of Technology Science and technology on Vehicle Transmission Laboratory Beijing Institute of Technology beijing Benz Automotive co. Ltd

A numerical model to predict film torque of hydro-visco.s clutch was *** model was established with co.putational fluid dynamics（CFD）.The pressure distribution,velocity of flow and film torque were obtained based on vertical-horizontal grooved plate and radial grooved plate *** boundary co.ditions,such as the relative rotation,the fluid temperature and the oil feeding pressure,were also *** results showed that the film torque of two kinds of grooved plate increased with increasing relative ***,the film torque decreased with increasing fluid temperature and feeding ***,the film torque of radial grooved plate was less than vertical-horizontal grooved plate at the same *** study showed that the model can efficiently calculate the film torque with co.plex geometry parameters and boundary co.ditions.

关键词： hydro-visco.s clutch(HVC) co.putational fluid dynamics film torque vertical-horizontal groove radial groove

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of reduction pretreatment process on evolution of micro-porosity in 42CrMo billet

引用

Journal of Iron and Steel Research International 2021年第4期28卷 413-423页

作者： Zhen Ning Wei Yu Hong-qiang Liu Qing-wu Cai co.laborative Innovation Centre of Steel technology University of Science and Technology BeijingBeijing 100083China HBIS Group co. Ltd.Shijiazhuang 050000HebeiChina

Reduction pretreatment(RP)process,which is implemented after the billet is co.pletely solidified,is an alternative process to further improve billet *** element method and experiment were used to investigate the effect of the RP process on the internal quality of 42CrMo *** ultrasonic testing technology was used to study the influence of the RP process on the *** a three-dimensional finite element model,the mechanism of the RP process on the porosity closure was *** experimental results show that the RP process eliminates the macro-porosities of the billet *** number of micro-porosities in the billets is effectively reduced,and the increase in deformation co.tributes to the reduction in *** with isothermal rolling,the RP process leads to a larger equivalent strain and hydrostatic integration in the billet center because of the temperature gradient,and the effect of the temperature gradient is greater with the increase in *** closure effect of micro-porosity is related not only to the stress state,but also to the distribution of *** increase in three-dimensional co.pressive stress is beneficial to the porosity *** the micro-porosities distributed densely,excessive stress co.ld induce micro-porosity co.lescence,which has the risk of inducing cracks.

关键词： Reduction pretreatment Temperature gradient Large deformation Micro-porosity Ultrasonic testing

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Inclusions in wrought superalloys:a review

引用

Journal of Iron and Steel Research International 2021年第8期28卷 921-937页

作者： Shu-feng Yang Shu-lei Yang Jing-long Qu Jin-hui Du Yu Gu Peng Zhao Ning Wang School of Metallurgical and Eco.ogical Engineering University of Science and Technology BeijingBeijing 100083China Gaona Aero Material co. Ltd.Beijing 100081China

Inclusions in wrought superalloys significantly affect the stability of the alloy properties and limit their use and devel-opment in aeroengines and other *** types and sources of inclusions in wrought superalloys were reviewed with analysis of the co.ditions of inclusion formation from the viewpoints of thermodynamics and *** ther-modynamic data for inclusion formation in nickel-based and co.alt-based alloys were summarized and *** damage of inclusions to the fatigue and tensile properties and workability of these alloys and the mechanisms of crack initiation and propagation caused by inclusions were also discussed,and the effects of inclusions with different charac-teristics on crack propagation were *** addition,the co.trol methods and mechanisms of inclusions in the triple smelting process(vacuum induction melting+protective electroslag remelting+vacuum arc remelting)were co.ered,providing a reference for improving the co.trol technology of inclusions in wrought ***,the difficulties and development trends for inclusion co.trol in wrought superalloys were discussed.

关键词： Wrought superalloy Triple smelting Inclusion co.trol method

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：