检索结果-南通市图书馆

Metadynamic Recrystallization of the As-cast 42CrMo Steel after Normalizing and Tempering during Hot Compression

Chinese Journal of Mechanical Engineering 2012年第5期25卷 853-859页

作者： QI Huiping li yongtang School of Materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China

The existing researches of hot ring rolling process are mainly based on forged billet. Compared with the existing process, the new ring casting-rolling compound forming process has significant advantages in saving materials and energy, reducing emission and reducing the production cost. The microstructure evolution of the casting materials during hot deformation is the basis of the research of the new process. However, the researches on the casting materials are rare. The metadynamic recrystallization of the as-cast 42CrMo steel after normalizing and tempering during the hot compression is investigated. The tests are performed on the Gleeble-1500 thermal-mechanical simulator. The influence rule of the deformation parameters on the metadynamic recrystallization is obtained by analyzing the experimental data. The kinetic model of the rnetadynamic recrystallization is deduced. The analysis results show that the metadynamic recrystallization fraction increases with the increase of the deformation temperature and the strain rate. The metallographic experiments are used to investigate the influence rule of the deformation parameters on the grain size of the metadynamic recrystallization. The experimental results show that the grain of the metadynamic recrystallization could be refined with the increase of the strain rate and the decrease of the deformation temperature during hot compression. The occurrence of the metadynamic recrystallization during the hot deformation is more difficult in as-cast 42CrMo steel than in forged 42CrMo steel. The research can provide the foundation for the further research of the hot deformation behaviors of the as-cast structure and theoretical support for the new ring casting-rolling compound process.

关键词： metadynamic recrystallization as-cast 42CrMo steel deformation parameters grain size

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

Fractal Characteristics and Microstructure Evolution of Magnetron Sputtering Cu Thin Films

引用

Chinese Journal of Mechanical Engineering 2013年第1期26卷 137-143页

作者： DU Shiwen li yongtang School of Materials Science and Engineering Taiyuan University of Science and Technology

How to describe surface morphology characteristic and microstructure evolution are the hottest researches of current thin film researches. But in traditional characterization of surface morphology, the roughness parameters are scale related. And the microstructure evolution of thin film during post-treatment is usually not considered in detail, To give a better understanding of the roughness of thin films topography, fractal method is carried out. In addition, microstrueture evolution of thin films is analyzed based on the crystallography and energy theory. Cu thin films are deposited on Si （100） substrates by magnetron sputtering, and then annealed at different temperatures. Surface topography is characterized by atomic force microscope （AFM）. Triangular prism surface area （TPSA） algorithm is used to calculate the fractal dimension of the AFM images. Apparent scale effect exists between the surface morphology roughness and film thickness. Relationship between the fractal dimension and roughness is analyzed by linear regression method and linear relationship exists between fractal dimension and surface roughness root mean square （RMS）. Fractal dimension can be characterized as a scale independence parameter to represent the complex degree and roughness level of surface. With the increase of annealing temperature, surface roughness and fractal dimension decrease. But when the annealing temperature exceeds the recrystallization temperature, due to the agglomeration and coalescence of Cu grain, surface roughness and fractal dimension increase. Scale effect and changing regularity of grain growth and shape evolution for different film thickness under different annealing temperatures are analyzed. Based on minimum total free energy, regularity of grain growth and changing is proposed. The proposed research has some theory significance and applicative value of Cu interconnect process and development of MEMS.

关键词： fractal dimension metal thin film surface morphology microstructure evolution

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

Advances in Compact Manufacturing for Shape and Performance Controllability of Large-scale Components-A Review

引用

Chinese Journal of Mechanical Engineering 2017年第1期30卷 7-21页

作者： QIN Fangcheng li yongtang QI Huiping JU li School of Materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China

Research on compact manufacturing technology for shape and performance controllability of metallic components can reanze the simplification and high-reliability of manufacturing process on the premise of satisfying the requirement of macro/micro-structure. It is not only the key paths in improving performance, saving material and energy, and green manufacturing of components used in major equipments, but also the challenging subjects in frontiers of advanced plastic forming. To provide a novel horizon for the manufacturing in the critical components is significant. Focused on the high-performance large-scale components such as bearing rings, flanges, railway wheels, thick-walled pipes, etc, the conventional processes and their developing situations are summarized. The existing problems including multi-pass heating, wasting material and energy, high cost and high-emission are discussed, and the present study unable to meet the manufacturing in high-quality components is also pointed out. Thus, the new techniques related to casting-rolling compound precise forming of rings, compact manufacturing for duplex-metal composite rings, compact manufacturing for railway wheels, and casting-extruding continuous forming of thick-walled pipes are introduced in detail, respectively. The corresponding research contents, such as casting ring blank, hot ring rolling, near solid-state pressure forming, hot extruding, are elaborated. Some findings in through-thickness microstructure evolution and mechanical properties are also presented. The components produced by the new techniques are mainly characterized by fine and homogeneous grains. Moreover, the possible directions for fin＇ther development of those techniques are suggested. Finally, the key scientific problems are first proposed. All of these results and conclusions have reference value and guiding significance for the integrated control of shape and performance in advanced compact manufacturing.

关键词： compact manufacturing shape and performance controllability high-performance ring parts thick-walled pipes

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

TOOTH CURVES AND ENTIRE CONTACT AREA IN PROCESS OF SPliNE COLD ROLliNG

引用

Chinese Journal of Mechanical Engineering 2008年第6期21卷 94-97页

作者： ZHANG Dawei li yongtang FU Jianhua School of Materials Science and Engineering Northwestern Polytechnical University Xi＇an 710072. China School of Materials Science and Engineering Taiyuan University of Science and Technology Taiyuan 030024 China

In spline rolling process, the contact area between roller and workpiece plays an important role in calculating rolling-force and rolling-moment. For the purpose of studying the contact area, contact state between roller and workpiece in process of spline cold rolling based upon cross rolling is analyzed. According to the suitable hypothesis, the mathematic model of roller-tooth-curve in optional position of rolling process is established. Combing the theory of conjugate curves with the theory of envelope curve, the corresponding mathematic model of workpiece-tooth-curve is established. By utilizing establishing mathematic models, the algorithm of entire contact area in rolling process is created. On the basis of the algorithm, calculation-program is compiled under MATLAB program language environment. The calculation-program actualizes quantitative analysis and quantitative calculation of contact areas. Utilizing the calculation-program, the influence of parameters on contact area is analyzed, and the tendency is consistent with the manufacturing experience. In consideration of rolling-force optimization, the primary process parameters may be selected according to results of calculation. The result of the present study may provide basis for research on rolling-force and rolling-moment.

关键词： Spline Cold rolling Contact area Mathematic model MATLAB

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

Rolling Force and Rolling Moment in Spline Cold Rolling Using Slip-line Field Method

引用

Chinese Journal of Mechanical Engineering 2009年第5期22卷 688-695页

作者： ZHANG Dawei li yongtang FU Jianhua ZHENG Quangang School of Materials Science and Engineering Taiyuan University of Science and Technology Taiyuan 030024 China School of Materials Science and Engineering Northwestern Polytechnical University Xi ＇an 710072 China Qingdao Cool Rolling Technological Research and Development Center Qingdao 266100 China

Rolling force and rolling moment are prime process parameter of external spline cold rolling. However, the precise theoretical formulae of rolling force and rolling moment are still very fewer, and the determination of them depends on experience. In the present study, the mathematical models of rolling force and rolling moment are established based on stress field theory of slip-line. And the isotropic hardening is used to improve the yield criterion. Based on MATLAB program language environment, calculation program is developed according to mathematical models established. The rolling force and rolling moment could be predicted quickly via the calculation program, and then the reliability of the models is validated by FEM. Within the range of module of spline m=0.5-1.5 mm, pressure angle of reference circle α=30.0°-45.0°, and number of spline teeth Z=19-54, the rolling force and rolling moment in rolling process （finishing rolling is excluded） are researched by means of virtualizing orthogonal experiment design. The results of the present study indicate that： the influences of module and number of spline teeth on the maximum rolling force and rolling moment in the process are remarkable; in the case of pressure angle of reference circle is little, module of spline is great, and number of spline teeth is little, the peak value of rolling force in rolling process may appear in the midst of the process; the peak value of rolling moment in rolling process appears in the midst of the process, and then oscillator weaken to a stable value. The results of the present study may provide guidelines for the determination of power of the motor and the design of hydraulic system of special machine, and provide basis for the farther researches on the precise forming process of external spline cold rolling.

关键词： external spline cold rolling slip-line field method rolling force rolling moment

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

Technology and Experiments of 42CrMo Bearing Ring Forming Based on Casting Ring Blank

引用

Chinese Journal of Mechanical Engineering 2014年第2期27卷 418-427页

作者： li yongtang JU li QI Huiping ZHANG Feng CHEN Guozhen WANG Mingli School of Material Science and Engineering Taiyuan University of Science and Technology Luoyang LYC Bearing Co. Ltd

Bearing ring is the crucial component of bearing. With regard to such problems as material waste, low efficiency and high energy consumption in current process of producing large bearing ring, a new process named ＂casting-rolling compound forming technology＂ is researched by taking the typical 42CrMo slew bearing as object. Through theoretical analysis, the design criteria of the main casting-rolling forming parameters are put forward at first. Then the constitutive relationship model of as-cast 42CrMo steel and its mathematical model of dynamic recrystallization are obtained according to the results of the hot compression experiment. By a coupled thermal-mechanical finite element model for radial-axial rolling of bearing ring, the fraction of dynamic recrystallization is calculated and recrystallized grains size are predicated. Meanwhile, the effects of the initial rolling temperature and feed rate of idle roll on material microstructure evolution are analyzed. Finally, the industrial rolling experiment is designed and performed, based on the simulation results. In addition, mechanical and metallographic tests are conducted on rolled bearing ring to get the mechanical parameters and metallographic structure. The experimental data and results show that the mechanical properties of bearing ring produced by casting-rolling compound forming technology are up to industrial standard, and a qualified bearing ring can be successfully formed by employing this new technology. Through the study, a process of forming large bearing ring directly by using casting ring blank is obtained, which could provide an effective theoretical guidance for manufacturing large ring parts. It also has an edge in saving material, lowering energy and improving efficiency.

关键词： bearing ring 42CrMo casting ring blank casting-rolling compound forming microstructure evolution

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

MECHANICS ANALYSIS ON PRECISE FORMING PROCESS OF EXTERNAL SPliNE COLD ROLliNG

引用

Chinese Journal of Mechanical Engineering 2007年第3期20卷 54-58页

作者： ZHANG Dawei li yongtang FU Jianhua ZHENG Quangang School of Materials Science and Enginering Taiyuan University of Science ＆ Technology Taiyuan 030024 China Qingdao Cool Rolling Technological Research and Development Center Qingdao 266100 China

According to the suitable assumption, the deformation process of external spline cold rolling is analyzed. By the graphing method, the slip-line field of plastically deforming area in process of external spline cold rolling is set up. Different friction-conditions are used in different contact areas in order to realistically reflect the actual situation. The unit average pressure on contact surface of the rolling process is solved according to the stress filed theory of slip-line. And the formulae of the rolling-force and rolling-moment are established. The theoretical result is well consistent with the finite element analysis. A theoretical basis is provided for the precise forming process of spline cold rolling and the production of external splined shafts.

关键词： External spline Cold rolling Slip-line Unit average pressure Rolling-force

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

Microstructure Evolution of Zr_(50)Cu_(18)Ni_(17)Al_(10)Ti_5 Bulk Metallic Glass during Cold-rolling

引用

Journal of Materials Science & Technology 2012年第8期28卷 756-760页

作者： Honghong Yan Yong Hu Zhijie Yan Xiaohua Zheng yongtang li School of Materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China

Zr5018Nil1AlTi10Ti5 bulk metallic glass has been rolled at room temperature up to 95% in thickness reduction, and the dependence of microstructure on the strain was investigated. With increasing thickness reduction, the full width at half maximum （FWHM） and crystallization enthalpy decrease gradually till 80%, and then increase evidently at 95%. It is revealed that the reversible transition between the ordered and disordered atomic configurations was found in the metallic glass as the deformation proceeds, which is further verified by the high-resolution transmission electron microscopy images. The final microstructure in metallic glass during cold-rolling is the net result of two competing processes between shear-induced disordering and diffusion controlled reordering.

关键词： Metallic glasses Cold-rolling Microstructure

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

基于应力三轴度的铸态42CrMo钢高温拉伸断裂行为分析

引用

机械工程材料 2024年第2期48卷 103-110页

作者：张在阳齐会萍李永堂陈园园张晋辉刘慧玲晋中职业技术学院机电工程系晋中030600 太原科技大学材料科学与工程学院太原030024 晋中学院机械系晋中030600

利用Gleeble-3500型热模拟试验机对不同缺口半径(0.5,1.0,2.0,4.0 mm)的铸态42CrMo钢缺口试样进行不同温度(1223,1273,1373 K)下的热拉伸试验,基于应力三轴度分析了其高温拉伸断裂行为。结果表明:较高拉伸温度下缺口试样的流变应力较小... 详细信息

利用Gleeble-3500型热模拟试验机对不同缺口半径(0.5,1.0,2.0,4.0 mm)的铸态42CrMo钢缺口试样进行不同温度(1223,1273,1373 K)下的热拉伸试验,基于应力三轴度分析了其高温拉伸断裂行为。结果表明:较高拉伸温度下缺口试样的流变应力较小;随着缺口半径减小,缺口试样流变应力和峰值应力增加,断裂应变减小;当缺口半径为0.5,1.0 mm时,应力三轴度最大值向最小横截面圆心转移;当缺口半径为2.0,4.0 mm时,拉伸过程中最小横截面圆心处的应力三轴度始终最大;随着缺口半径增加,应力三轴度减小;温度由1223 K升至1373 K,试样断口组织平均晶粒尺寸增大;缺口半径由0.5 mm增加至4.0 mm,平均晶粒尺寸增大,微空洞且尺寸及面积分数增加。

关键词：铸态42CrMo钢应力三轴度高温拉伸断裂行为

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

RESEARCH ON THE ENERGY ECONOMIZATION OF ELECTRO-HYDRAUliC HAMMER

引用

Chinese Journal of Mechanical Engineering 2000年第1期13卷 54-69页

作者： Lei Bufang li yongtang liu Jiansheng (Department of Mechanical Engineering, Taiyuan Heavy Machinery Institute) 太原重型机械学院山西太原

The research on the driving principle and economization of energy of electro-hydraulic hammer is discussed. By means of the balance chart of energy, the method and formulas to calculate every level efficiency and the total efficiency of steam drived hammer are *** the aid of actual data of plants,the actual efficiency of steam drived hammer is got. The working principle and the driving system of electro-hydraulic hammer are introduced. The procedure of energy energy of this hammer is analyzed. The utilization ratio of energy of this type of hammer is got. It is shown that the efficiency of electro-hydraulic hammer is 7 times as much as that of steam drived hammer.

关键词： Steam hammer Electro-hydraulic hammer Economization

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

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：