bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal Simulation Study of 900MPa Grade High-Strength Low Alloy Steel in Welding Procedures
Authors: Yang Di Xin , Sun Yuan Fang
Published: December 2011

Hydraulic support is an important part of fully mechanized equipments. The constructional steels of hydraulic support with international advanced level mainly adopt the high-strength welding structural steel with its tensile strength of more than 700~1000MPa.This paper analyzes the chemical compositions features of S890 high-strength low alloy steel for 900MPa grade.The Influence of welding parameters,peak temperature and on the microstructures and mechanical properties of welding HAZ of S890 high-strength low alloy steel were investigated by thermo-simulated tests, The influence of welding heat input on the mechanical behaviors of the welded joint was also investigated. The results show that the microstructures of S890 steel change from tempered martensite to bainite and a little ferrite , pearlitic when welding heat input changes from low to high, and accompany the austenite grains coarsening ,so the impact toughness and hardness of welding HAZ at lower peak temperatures and shorter are higher than that at higher peak temperature and long . Welding HAZ produced by the second weld bead will overlap partially with the HAZ produced by the first weld bead. In this area, primitive microstructure tempers again or partial re-phase transformations and re-cools,but the area involved in the overlap is limited,so the influence on the properties of S890 steel is not obvious. In covered arc welding,the influence on the welded join strength of S890 steel is not distinct when heat input change in a certain scope, but the plasticity of the welded join falls off steeply as heat input increases. Keywords: S890 steel; high-strength low alloy steel; weld performance; hydraulic supports
Numerical Simulation of Rotational Tool Shoulder Shape’s Effect on Transfer Behavior of Welding Plastic Metal in Friction Stir Welding
Authors: Ji Shu De , Zhang Li Guo , Jin Yan Ye , Luan Guo Hong
Published: December 2011

The plunging process of rotational tool is simulated while the shapes of rotational tool shoulder are inner-concave-flute, concentric-circles-flute and three-spiral-flute respectively. The effect of rotational tool shoulder’s shape on transfer behavior of welding plastic metal is obtained. The results show that whatever the shape of tool shoulder is, the metal of contact surface in the workpiece undergoes relatively big plastic transfer. To the rotational tool with three-spiral-flute shoulder, the transfer velocity and displacement of plastic metal inside the workpiece slowly decrease with the increase of the distance away from the surface of workpiece. To the rotational tool with the inner-concave-flute shoulder or the concentric-circles–flute shoulder, the transfer velocity of metal inside the workpiece is very small and the value is close to zero. Using the rotational tool with no pin, the experiment of friction stir welding is processed. The results show that the size of every grain in weld nugget zone which is made by the rotational tool with three-spiral-flute shoulder is nearly the same. The degree of uniformity of grain made by three-spiral-flute shoulder is much higher than that made by inner-concave-flute shoulder or concentric-circles-flute shoulder.
Numerical Simulation and Experiment Study on the Blanking Force for AISI-1020 and AISI-1045 Fine-Blanking with Negative Clearance
Authors: Li J.H. , Zhang Zhong Mei
Published: December 2011

Machining experiments of fine-blanking with negative clearance show that the blanking force is very different from ordinary blanking in different blanking stages. Studying on the blanking force size of fine-blanking with negative clearance in different blanking stages is a very important significance for studying die wear and analyzing the state of material stress-strain. Firstly, numerical simulation and stress state analysis of the fine-blanking with negative clearance are carried out, with DEFORM-metal forming finite element analysis software. Afterward the relationship curve of blanking force and stroke are measured, and the blanking force with different blanking stages of fine-blanking with negative clearance is analyzed by the simulation and the experiment. The analysis result shows that the simulation blanking force is bigger than the experimental result (error about 15%), but the blanking force variation tendency is accordant. while the punch pushes down within 0.1mm, the blanking force changes quickly. The metal sheet will enter into the state of plastic deformation after the blanking force reaching maximum value. Along with the punch continues to move down, the area of shear zone is decrescent so that the blanking force inches down, and the blanking force reaches a certain value in the place of blanking allowance value finally. With punch pushing the metal sheet to enter the plastic state and punch downward the place of the allowance value, the metal sheet sustained the big blanking force all the time as well as the deformation zone material keeps the plastic deformation. The research result provides theoretic reference and the experimental data for the practice application of fine-blanking with negative clearance, and has instructive significance and reference value to mould design.
Antiwear Behavior of Micro-Arc Oxidated Coating Rubbing on Abrasive Paper
Authors: Tang Yan , Xu Jin Yong , Ye Fang Yong , Gao Cheng , Zhang Jing Chun , Liu Ya Juan
Published: December 2011

To research the tribological properties of micro-arc oxidized ceramic coating in extreme friction condition, ceramic coatings were tested with 1000# waterproof sand paper friction pair for the first time. The phase composition of ceramic coating was analyzed by X-ray diffraction (XRD).Micro structures of ceramic coating surface were observed by scanning electron microscopy (SEM). Friction coefficient of ceramic coating was measured by ball-on-disc wear tester with a 3 mm steel ball. Wear weight loss and wear rate of ceramic coating were measured and calculated by photoelectron balance. The results show that ceramic coatings in various roughnesses have different former wear rates and close wear rates at stable stage. Under water-lubricated condition, wear rate is as low as 0.2 mg/min to 0.3 mg/min. The antiwear behavior of ceramic coating is about 5.3 times compared to aluminium alloy at dry friction. While under water-lubricated condition, the antiwear behavior of ceramic coating improves about 94 times compared to aluminium alloy. The friction coefficient of loose layer is higher than compact layer at dry friction. And there are positive correlation between wear rate and surface roughness of ceramic coating. So it can be verified that compact layer has well antiwear behavior better than loose layer.
Study on Formability of Micro-Feature in the Coining Process
Authors: Zheng Wei , Wang Guang Chun , Wu Tao , Song Li Bin
Published: December 2011

In micro-manufacture field, micro-forming is paid much attention due to its efficiency for mass production. However, owing to the particularity of deformation, mass researches for specialized micro-forming processes to direct the industrial production are of great urgency. As a similar process with the micro-forming, the forming property of micro-feature forming in coining process was investigated by the experimental research and numerical analysis. Firstly, utilizing the workpieces with different thicknesses and micro-feature sizes, the coining processes were numerically simulated to study the forming property of micro-feature. The height of micro-feature was selected as the evaluation criteria for the deformation behavior. Then, the pure copper specimens with different thicknesses were coined experimentally, using a die with a micro-hole by the universal testing machine to verify the simulation results. Finally, a modified scheme was successful to be proposed which could improve the manufacturability of the processes. The research results could provide technical references for manufacturing micro-parts and those with micro-features.
Finite Element Simulation of Limit Load of Components at High Temperature
Authors: Peng Jian , Zhou Chang Yu , Xue Ji Lin , He Xiao Hua , Dai Qiao
Published: December 2011

The creep of materials makes it difficulty to determine the limit load of component at high temperature. In this paper, limit load was obtained by finite element simulation according to isochronous stress versus cumulative strain data and creep failure criterion at high temperature. Firstly, isochronous stress versus cumulative strain data of P91 steel was generated. In finite element analysis code ABAQUS, isochronous stress versus cumulative strain data was replaced by equivalent elastic-plastic constitutive relation. Then, sustained load versus cumulative strain curves at high temperature during service was obtained after finite element simulation. At last, limit load at high temperature during given working hours was determined based on the restriction of total strain at key point of specific component. The restriction of total strain which could also be regarded as long-term fracture strain was discussed in this paper. Finite element simulation of limit load of component at high temperature is simple and reasonable. Limit load of complex component at high temperature during given working hours can be obtained by this method. Using this method, limit loads of a pipe with local wall thinning defect and a branch junction at high temperature during given working hours were obtained as examples.
A Method of Establishing Temperature Schedule during ASP Hot Strip Rolling
Authors: Zhao Yan Feng , Zhang Dian Hua , Xu Yun Bo , Hou Xiao Ying , Wang Guo Dong
Published: December 2011

Based on the actual production data of ASP (Angang Strip Production) hot strip rolling line, mechanical properties of thin gauge X70 pipeline steel were simulated by BP neural network method. Recursive functions were used to verify the mechanical properties which calculated by BP neural network. Based on predicted mechanical properties with high precision, BP neural network and Genetic Algorithm (GA) were combined to establish the temperature schedule of X70 pipeline steel during ASP hot strip rolling. It is shown that there are four important temperatures during ASP hot strip rolling, such as rough rolling temperature, refine start rolling temperature, refine finish rolling temperature and coiling temperature. Temperature difference of adjacent stages and temperature of former stage is a linear function relationship. For a given mechanical properties, deviations between simulated temperature and actual temperature are within ±10°C. This method can be used to produce different strips with the same compositions but different strengths by regulating suitable temperature schedule, so it is effective to resolve conflicts during hot strip rolling.
Simulation for the Fluctuation Effect on the Dendrites Growth with Phase Field Method
Authors: Hou Hua , Zhao Yu Hong
Published: December 2011

The dendrite growth process was simulated with the Phase Field Model coupled with the fluctuation. The effect of fluctuation intensity on the dendrite morphology and the thermal fluctuation together with the phase field fluctuation on the forming of side branches were investigated. Result shows that with the decrease of thermal fluctuation amplitude, the furcation of dendrites tip also decreased, transverse dendrites become stronger and lengthways dendrites becomes degenerate, Doublon structure disappeared, finally a quite symmetrical dendrites structure formed. Thermal fluctuation can result in the unsteadiness of dendrites side branches, it is also the main reason of forming side branches, yet phase field fluctuation has little contribution to the side branches, it is usually ignored in the calculation; when the value ofFuis appropriate, the thermal noise can lead the side branches, but cannot change the steady behavior of the dendrites’ tip.
High Temperature Deformation Behavior and Microstructure Preparation of Cu-Ni-Si-P Alloy
Authors: Zhang Yi , Tian Bao Hong , Liu Ping
Published: December 2011

The hot deformation behavior of Cu-Ni-Si-P alloy have been investigated by means of isothermal compression tests on a Gleeble-1500D thermal mechanical simulator in the temperature ranges of 873-1073 K and strain rate ranges of 0.01-5s-1. The results show that the dynamic recryatallization occurs in Cu-Ni-Si-P alloy during hot deformation. The peak stress during hot deformation can be described by the hyperbolic sine function. The influence of deformation temperature and strain rate on the peak stress can be represented using the Zener-Hollomon parameter. Moreover, the activation energy for hot deformation of Cu-Ni-Si-P alloy is determined to be 485.6 kJ / mol within the investigated ranges of deformation temperature and strain rate. The constitutive equation of the Cu-Ni-Si-P alloy is also established. Keywords: Cu-Ni-Si-P alloy; Hot deformation; Dynamic recrystallization; Zener-Hollomon parameter.
Design and Optimization of Loading Trajectory for S-Skin Stretch Forming Process by Simulation
Authors: Zhang Yan Min , Li Xiao Qiang , Song Ke Xing
Published: December 2011

Stretch forming is one of the primary methods in skin forming process. Uniform strain distribution and springback are main factors which affect the precision of air skin. In the article the stretch forming process based on S-skin was analyzed. Firstly the parameters ranges of the loading trajectory were designed through the analytic method. Secondly the initial loading trajectory was optimized through finite element numerical simulation. The optimization processes was performed through FET software integrated with the optimization arithmetic. The motion parameters of jaw and machine’s instructions were selected as design variables. Optimization mathematics model was set up which objective is to reduce springback and improve the strain distributes uniform degree. During optimization the maximum main strain and thickness thinning rate of elements were restricted in permissive range. The forming degree of each stage was rational distributed, and the reasonable loading trajectory was founded. The result shows that the reasonable loading trajectory is including pre-stretch, wrap, press and after stretch. After optimization the strain distributes uniformly and the maximum main strain is between 3％～5％. The maximum stretching rate which appears in the shoulders area is less than 6%. In the concave area in which the insufficiency deforming can be occurred easily the strain achieves about 3%, and the deformation is enough. After optimization the unloading springback is decreased distinctly. The average springback of all elements is 0.47mm which reduces 30% compare with before optimization. The result meets the manufacture requirement.
2.5D FEM Study and Optimization of Roll Pass Design in Roughing Mill Group
Authors: Aksenov Sergey A. , Logashina Irina V. , Chumachenko Eugene N. , Kotas Milan
Published: December 2011

The subject of the paper is a study of the material behaviour during hot rolling. The process considered is a rolling of round bar in roughing mill group which consist of four passes. The computer simulation of the process shows that the local plastic deformations which appear in the material are extremely large. This fact can leads to extension of surface defects. The dependences of maximum local plastic deformation on geometrical parameters of the calibres have been obtained and analysed during this study. The investigations performed, led to the development of new roll pass design which almost halved the maximum value of local plastic deformation in the material during the rolling. Since full 3D FEM models needs significant amount of computer memory and CPU time, it was not suitable for the performed study which involves a bulk of simulations with different initial conditions. Therefore, the quick algorithms for simulation of rolling processes which based on so-called “2.5D” method have been used. This method, due to number of simplifications, is significant faster then conventional 3D FEM, and at the same time it allows to reach good accuracy of the model. The developed computer software SPLEN(Rolling) which implements “2.5D” FEM simulations was applied for computations and analysis of the results. This software is able to predict the shape evolution of rolled material, as well as distributions of strain, strain rate and temperature within the volume of deformation zone. It has been shown that computer simulation based on “2.5D” FEM with SPLEN(Rolling) software can by efficiently used for optimization of technological procedures in rolling industry.
Numerical Simulation of Spinodal Deposition in Cu–6at.%Ni–3at.%Si Ternary Alloy Using of Phase Field Method
Authors: Long Yong Qiang , Liu Ping , Liu Yong , Jiao Shu Guo , Tian Bao Hong
Published: December 2011

Based on Cahn-Hilliard nonlinear diffusion equation, the phase field model has been established for ternary alloy spinodal decomposition, which directly couples with Calphad thermodynamics and dynamics calculation and takes into account the effect of the coherent elastic energy. The simulated microstructures of spinodal decomposition were carried out in the isothermally-aged of Cu-6at.%Ni-3at.%Si alloy. The results indicate that the spinodal decomposition takes place at the early stage of Cu-6at.%Ni-3at.%Si alloy aging at temperatures of 723K, forming two-phases mixture of Cu-rich and Ni/Si-rich, and the decomposition microstructures are distributed in a semi-interconnected labyrinth-like form. Under the effect of the coherent elastic energy, the decomposition microstructures demonstrate the obvious anisotropic characteristics, and present interconnected rectangular stripes aligned along [10] and [01] directions. The growth of the decomposition microstructures is in accordance with the growth law of growth exponentn≈0.29, slightly less than the LSW’s prediction.
Finite Element Simulation of the Nosing Process of Metal Tubes with a Conical Die
Authors: Chu Liang , Shi Li Jun , Bi Yan , Bi Da Sen
Published: December 2011

In this paper, the nosing process of metal tube with a conical die is investigated using the finite element method, and a series of simulations on the tube nosing process by using the program ABAQUS is carried out. The concrete process of tube nosing deformation is described. Some simulation results on tube nosing deformation such as the distributions of the Von Mises stress and effective strain, the material thickness variation of deformation zone are obtained and analyzed.
The Microstructure and Formability Study on DP Steel of Lightweight Automobile
Authors: Wu Jin , Bi Da Sen , Chu Liang , Zhang Jian , Li Yun Tao
Published: December 2011

Dual phase (DP) steel is a high strength steel for auto-panel. In this paper, mechanical property, forming ability, baked-hardening and work hardening properties of high strength steel DP450 are studied by experiments, and compared with those of steel MS6000.And theoretical research on predicting the forming limit of steel DP450 by the NADDRG model. The established mathematic model for relativity is of practical usefulness. Experimental results reveal that the yield strength of steel DP450 is about 7.2% lower than the MS6000,and the break strength increases by 18.9%,while the elongation increases by 19%.The strain hardening exponent of steel DP450 are superior to those of MS6000.The results show that mechanical property of high strength steel DP450 is better than that of MS6000,while forming ability of DP450 is not lower than that of MS6000.And baked-hardening and work hardening properties of steel DP450 are better than those of MS6000.The steel sheet DP450 owned a good forming ability.
A One-Point Quadrature Element Used in Simulation of Cold Ring Rolling Process
Authors: Zhang Xue Bin , Zhao Xin , Zhang Yan Min , Li Zhi Gang
Published: December 2011

A single-point load will be applied on the ring in the cold ring rolling process when the ring vibrates violently. This arouses hourglass in finite element simulation of the process using reduced integration element. A one-point quadrature element with hourglass control developed by Hu is used, and the user-defined control parameters are not required. Hourglass energy can be reduced to 3 percent of the internal energy. The element is applied to simulation of a pure radial cold ring rolling with rectangular section. Compared with the experimental results, the simulation results are proved to be accurate. Key-Words: one-point quadrature; Hourglass control; finite element; cold ring rolling
The Numerical Simulation of Conductive Body Forming Process and Mould Design
Authors: Gao Jian Xin , Zhao Pei Feng , Song Ke Xing , Wang Qing
Published: December 2011

T2-copper conductive body is a important part used in high voltage switch, it has poor machining process due to the complex shape. Through Deform numerical simulation, conductive body was formed by open-die forging and closed die forging. In the open-die forging simulation，heat transfer coefficient between blank (880°C) and open-die (200°C) is 11, the surrounding environment temperature is 20°C, friction factor is 0.3. The main open-die forging process parameters is: outer draft angle α=6.5°; inner draft angle β＝10°; bridge width b＝5、8、11mm. punching skin and cylindrical blank. Simulation results show that forging can meet the requirement while properly adjusting mould parameters. The main size of closed-die forging working parts is designed according to the conductive body graph, no draft angle and ring blank of external diameter Φ111mm and inside diameter Φ93mm with the same volume of conductive body. The simulation results shows that forging can be formed using open-die forging, and it is difficult to form product by the process of the closed-die forging for ring blank because of the restriction of solid state metal liquidity, many regions of the filling is not sufficient. Open-die forging and casting blank-closed die forging are both used in actual production. The casting blank-closed die forging is a more reasonable forming process compared with the open-die forging as metal volume of distribution is solved, higher utilization rate of material, more simple process in following work and the like. To make it more suitable for practical production, appropriate adjustments of some parameters was made in the mold design process based on the numerical simulation. Keywords: open-die forging; casting blank–closed die forging; numerical simulation
Application of Optimization Algorithms in Injection Molding Process Parameters Optimization
Authors: Hu Ze Hao , Wei Wei , Liu Juan , Liu Kun
Published: December 2011

In this paper, the numerical simulation and calculation of injection molding process are taken in the Moldflow software. The BP artificial neural network combining with the orthogonal experiment design method is used to set up the injection molding process agent model, genetic algorithms are applied to realize global optimization, finally, the optimal combination of process parameters of each quality indicators is obtained.
Finite Element Simulation of Biting Process of Cold Rolling Strip for 6-High Mill
Authors: Ma Xu , Ma Jing Yun , Feng Zhi Long , Cui Hong Lei , Yang Yu , Li Yun Tao , Zhang Jian , Ding Yan Hong , Li Jian Ping
Published: December 2011

In this work, On the basis of software ANSYS/LS-DYNA, the strip cold rolling simulation model was established. The process from biting to rolling steady were simulated and investigated for 6-high UCM (6-high middle rolls shift type HC-mill with middle roll bender) cold mill, including the stress, stain state, and velocity field of the workpiece and rolls. The result states that the stability of Biting Process of 6-high cold mill is preferable and the impact of biting process on the roll is acceptable. The simulation regularity corresponds well with the measurements.
Application of an Improved Trust-Region Method to Rigid-Plastic Finite Element Analysis in Strip Rolling
Authors: Song Shu Ni , Liu Jing Yi , Qian Jin
Published: December 2011

Rigid-plastic finite element analysis (RPFEA) is an efficient and practical method to calculate rolling parameters in the strip rolling process. To solve the system of simulations equations involved in the RPFEA, a numerous of numerical methods, including the standard Newton-Raphson method, the modified Newton-Raphson method, and etc., have been proposed by different researchers. However, the computational time of the existed numerical methods can not meet the requirement of the online application. By tracking the computational time consumption for the main components in the standard Newton-Raphson method used in finite element analysis, it was found that linear search of damping factor occupies the most of the computational time. Thus, more efforts should be put on the linear search of damping factor to speed up the solving procedure, so that the online application of RPFEA is possible. In this paper, an improved trust-region method is developed to speed up the solving procedure, in which the Hessian matrix is forced to positive definite so as to improve the condition number of matrix. The numerical experiments are carried out to compare the proposed method with the standard Newton-Raphson method based on the practical data collected from a steel company in China. The numerical results demonstrate that the computational time of the proposed method outperforms that of the standard Newton-Raphson method and can meet the requirement of online application. Meanwhile the computational values of rolling force obtained by the proposed method are in good agreement with experimental values, which verifies the validity and stability of the proposed method.
Study on Load Control and Optimization of Rotary Forging Method for Heavy and Thick-Walled Container Head by FEM
Authors: Wang Meng Han , Xiang Dong , Li Yu Feng
Published: December 2011

In this study, the finite element method (FEM) was used to simulate the rotary forging process of a heavy and thick-walled container head, and the problems about load, strain distribution and optimization of rotary forging method were studied. First, five controlling factors of load were defined, which were single reduction amount (δ), reduction rate (ν), thickness of top die (ω), rotary angle (θ) and rotary way (γ) respectively, and their influence degree on load was studied later. Then the influence of γ on strain distribution was investigated. The results indicate δ, ν and ω have a strong influence on load, while θ and γ have a small influence on it; the strain distribution under crossed rotary way which is proposed in this paper is more homogeneous than stepwise rotary way. Based on the research results, a new multi-stage rotary forging method was proposed, by which load and strain distribution could be controlled effectively by means of an optimized combination of the five controlling factors in different forming stages. The simulation results are in good agreement with practical production. This study can provide valuable guidance in load control and process optimization for other similar heavy blind-hole forgings. Keywords: Heavy and thick-walled container head, FEM, Rotary forging method, Load control, Strain distribution
Experimental Study of Hot Forming Process by Direct Resistance Heating
Authors: Men Zheng Xing , Zhou Jie , Xu Zhi Min
Published: December 2011

In order to increase heating efficiency and decrease heating time, a new hot-forging method by means of direct resistance heating was investigated in this paper. Based on the approach, the hot upsetting experiments with cylindrical billet of 42CrMo4 were performed. Moreover, the influence of the multi-layer aluminium foils inserted between the billet and the die as a forming condition on heating and forming was researched. The results of the experiments show that prior to forming the billet could be heated quickly to forming temperature in about 10 seconds. During the upsetting process the billet cooling rate was effectively decreased and the forming time was extended in relation to the resistance heating. The insertion of multi-layer aluminium foils not only improved the efficiency of the heating, but also avoided the plastic deformation of the die and the occurrence of cracks on the billet’s surface. Keywords: Resistance heating, Hot forging, upsetting, Aluminium foils Introduction
Research on Boronizing of the Whetstone Forming Die
Authors: Chen Jing , Hao Shao Xiang , Fan Xun
Published: December 2011

The main failure forms of whetstones forming die is serious wear on the work face, and the boronizing technology can be used to improve the hardness and wear resistance on the work face of the whetstones forming die. In this paper, the orthogonal test was used to obtain the optimum parameters of temperature, time and the amount of addition of rare earth in the boronizing process of die. The line scan spectrum shows that there are some of elements such as B, C, Al, Cr, Si and Fe etc in boronizing layer, and their content are changed during boronizing. The microhardness of boronization layer was measured, and the result showed that maximum value of microhardness of boronizing layer appears in subsurface, not in surface, and lowers along depth of boronizing layer. By comparing different wear curve of abrasive samples with different treated, we can see that the highest wear resistance of surface is in the sample with the optimization of boronization treatment +970°C quenching and 200°C tempering; followed by quenching and tempering treatment; the lowest wear resistance of the surface is the sample without the boronizing treatment, and the rest sample are between these two samples. After optimization of boronization treatment +quenching and tempering, the lifetime of the whetstones forming die with boronizing is 3.5 times than the old one. Keywords: Boronizing; Whetstone; Forming Die
Numerical Simulation on the Casting Process of Gray Iron Brake Pad
Authors: Liang Chun Yong , Li Hai Peng , Wang Li Hui , Wang Hong Shui , Zhao Xiang Jun
Published: December 2011

Based on the analysis of primal process and structure of gray iron brake pad failing early, hydrodynamic software Flow-3D was used to simulate the defect distribution and temperature fields of different improved technology schemes. According to simulation results, the merits and faults of all schemes were investigated and the feasible casting system was determined. The results showed that uniform temperature distribution could be achieved and potential defects mainly distributed in gate riser or nonworking surface when adopting the casting system with single ingate, which gave brake pad better service performance.
Investigation on Slurry Filling Sequence during Semi-Solid Forming of Complex Aluminum Part
Authors: Wang Kai Kun , Wang Fu Yu , Wang Yuan Ning
Published: December 2011

Semi-solid forming technology is a short metal processing method between the liquid casting and solid forming. Many forming factors have been found concerning the quality of the forming part. In this study, the influences of slurry filling sequence were investigated in semi-solid forming one complex aluminum part. Two different slurry filling methods were designed. Method one is thixo-upsetting + compound extrusion, method two is thixo-upsetting + extrusion. The experimental results showed that the optimised method of thixo-upsetting + extrusion could be the best strategy in improving the part quality during thixo-forming of aluminum alloy A356.
Analysis on Contact Forms of Interface in Wafer CMP Based on Lubricating Behavior
Authors: Zhang Sheng Fang , Su Jian Xiu , Du Jia Xi , Kang Ren Ke
Published: December 2011

Chemical mechanical polishing (CMP) has become the most widely used planarization technology in the semiconductor manufacturing process. In this paper, the distinguish method of lubricating behavior in wafer CMP had been analyzed in theory firstly. Then, the tests of wafer CMP with silicon wafer and deposited copper wafer at different polishing pressure had been done. By the test results, the Stribeck curves obtained showed obvious smooth. But in normal wafer CMP conditions, the friction coefficient of polishing area was above 0.1. By analyzing the experimental results, it was concluded that the lubrication state in CMP interface is belong to the boundary lubrication and the material removal is the process of bringing and removed of the chemical reaction boundary lubricating film on wafer surface constantly. The contact form between the Wafer and the polishing pad is the solid-solid contact. These results will provide theoretical guide to further understand the material removal mechanism of in wafer CMP. Keywords: Chemical mechanical polishing, material removal mechanism, lubrication form, boundary lubrication.
Application of Digital Simulation Software ANSYS in Rolling Concrete Dams Construction Technology
Authors: Zeng Gui Xiang
Published: December 2011

Taking a large hydropower station in Xinjiang Autonomous Region as an example, and based on the limited unit method, the structure and seism forces features and response rules of rolling concrete gravity dam under different construction conditions were studied. The purpose for the paper is to understand dam working status under the different design conditions, and to evaluate anti-earthquake safety capability. It is proved that the present findings should play an important significance in the development of rolling concrete dam construction technology. Key words: Rolling Concrete Gravity Dams, Limited Unit Methods, Static Force Analysis, Dynamic Features.
Rigid Plastic FEM Model of Fast Solution to Strip Rolling
Authors: Mei Rui Bin , Li Chang Sheng , Liu Xiang Hua , Bao Li
Published: December 2011

Rigid plastic finite element method (RPFEM) is one of the most efficient numerical methods during the rolling process. Realizing FEM online application has been main target for many researchers. The influence of compile method, elements number, compressible parameter, friction factor and convergent criteria were investigated and RPFEM model of fast solution to strip rolling was proposed in this work. Compile method and compressible parameter have less influence on calculated rolling force. However, the iteration steps are reduced and computational efficiency is improved greatly with compile method of release and compressible parameter 0.01. The change of calculated rolling force becomes less but iteration steps become more and more with the increment of elements number. Both accuracy and efficiency is satisfying with the change of elements number from 50 to 200. In addition, the typical rolling schedule from a certain plant has been solved with the developed program FFEM-2D by FORTRAN. The predicted rolling force has a good agreement with the measured value. The iteration steps change from 12 to 36 and computational time is less than 200(ms) with the model in one pass rolling. Therefore, the accuracy is satisfying and computational time fully meets the basic requirements of FEM online application. Keywords: Rolling; RPFEM; Fast solution; Computational time
Study on Temperature Change Rule of Sprayed Composite Powders in Flight
Authors: Liu Hong Wei , Wang Jian Jiang , Sun Xiao Feng , Qiu Ji
Published: December 2011

The temperature change process of the single sprayed composite powder during the self-reactive spray forming process for preparing the Ti (C,N)-TiB2 ceramic preforms was numerically simulated by means of finite element analysis. The results show that after the sprayed composite powder with grain size of 50μm has entered the flame field for 0.35ms, the surface temperature of it will reach the igniting temperature and the self-propagating high-temperature synthesis (abbr. SHS) reaction will take place. The heating rate of the particle in this period is about 2.82×106°C/s. After the SHS reaction has taken place, the heating rate becomes quicker because of the double function of the flame and the reactive heat release. When the temperature of the sprayed particle is higher than that of the flame, the heat exchange process will turn into heat absorption from heat release, which leads to the great drop of the heating rate (about 1.20×106°C/s). The composite powder completes the reaction in 0.88ms and reaches the highest temperature of 2920°C, which makes it become a ceramic droplet. After the reaction has finished, the droplet cools down quickly from exterior to interior, and the surface temperature of it descends to the theoretic eutectic melting point of the composite ceramics (2620°C) after 0.34ms. Then the droplet begins to solidify at some degree of supercooling and becomes ceramic particle. The numerically simulated results before, during and after the reaction match the water-quenching experiments of the sprayed particle with particle size of 50μm during the corresponding period. It indicates the heat process of the sprayed composite powder on the whole, which is composed of being heated, heat releasing, cooling and solidifying.
Valence Electron Theoretical Analysis of Mechanical Properties in Low-Alloy Steel
Authors: Sun Chuan , Li Yun Kai , Jiang Lin
Published: December 2011

The mechanical properties in low-alloy steel are studied systematically from the view of valence electrons using the Empirical Electron Theory in solid and molecules (EET). Two new valence electron structure parameters ρcvand ρlv, which have closely relation with the mechanical properties of alloy steel are summed up according to the basic idea of EET. The values of the two new valence electron structure parameters in carbon steel and alloy steel which contains Cr, Mn, Ni, Si, W and Mo are calculated. The result demonstrates that ρcvhas a very good corresponding relationship with intensity, and ρlvhas a very good corresponding relationship with plasticity. In this note, a quantitative empirical formula between the valence electrons structure and the intensity and plasticity of alloy steel is initially set up. Keywords: EET, valence electron structure, mechanical property, low-alloy steel
Effect of Red Extractives of Plantation Leaves on Bamboo Biomass Mildewing
Authors: Wu Feng Juan , Peng Wan Xi , Qin Dao Chun , Lu Fang
Published: December 2011

Bamboo is so easy to get mildewed that bamboo products are still low value added. Therefore, the effect of red extractives from 28 tree leaves on bamboo biology mildewing was studied basing on full-factor test. The result was as follows: (1) most red extractives of tree leaves can inhibit the growth of P. expansum, but a few can inhibit the growth of A. alternate; (2) The red extractives from tree leaves of Deodar cedar, Eucalyptus grandis, Eucalyptus dunnii and pear were the most effective to control spore germination of P. expansum, and those of Manglietia glauca, Osmanthus fragrans, and Melia toosendanin were the most effective to control spore germination of A. alternata; (3) The effect of the red extractives from Pinus taeda, Eucalyptus grandis and Santalum album on bamboo biomass mildewing was highly remarkable on mildew-proof by outdoor test. Our result pointed out the direction for the development of the biological mildew inhibitor from tree leaves. Key words. tree leaves, bamboo biomass, benzene/alcohol extractives
Numerical Simulation and PIV Test on Flow-Field Character of Zinc-Silica Composite Electrolyte
Authors: Fan Yun Ying , Xu Jian Xin , Jiang Ye Hua , Wang Wen Quan
Published: December 2011

Composite electrodeposition is one of the most important metallic material surface finishing technology and metal-based composite material preparation technology. Electric field and flow field are the two main influence factors during electrodeposition process of composite coatings. In this paper, numerical simulation of flow-field of zinc-silica composite electrolyte is finished by FLUENT software and the actual flow state is recorded by Particle Image Velocimetry (PIV). The research work is also focused on influence of current and stirring intensity on flow character of electrolyte. The electrolyte composition and plating conditions are: ZnCl280 g/L, KCl 220 g/L, H3BO325 g/L, brightening agent 0.5 g/L, pH value of electrolyte 5.5, temperature 25°C, mass concentration of SiO2particles in electrolyte 1 g/L. The average particle size of SiO2particle is 11.07 μm. The stirring intensity is controlled between 0 and 3000 rpm, and current is controlled between 0 and 0.5 A. The results show that influence degree of stirring on flow field is much greater than current, and the numerical simulation of flow field finished by FLUENT software is approximately similar to the actual flow charactor recorded by PIV.
Modeling Cation Distributions of PbZr0.5Ti0.5O3
Authors: Hui Qun , Tucker Matthew , Chen Zhi Qian
Published: December 2011

We use neutron total scattering measurements with reverse Monte Carlo analysis methods incorporating an atom-swapping algorithm to investigate the short-range Zr/Ti cation ordering at the perovskite crystalloraphic B sites and micro structure within PbZr0.5Ti0.5O3solid solution at different temperature. Our results show that there is no Zr/Ti ordering at the B sites. TiO6and ZrO6units are rotated and distorted. The amplitude of rotations of the TiO6units is larger than that of the ZrO6units, accompanied by more distortions of the angles within the TiO6units.
Numerical Simulation of Flow Field and Temperature Field on Aluminium Alloy Engine Cylinder in Casting Process
Authors: Wu Hua , Shi Hai Ming , Liu Hai Feng , Xia Zhen Jia
Published: December 2011

Casting properties and process improvement of A356 aluminium alloy which is used to cast automobile engine cylinder is investigated in the present paper. The effects of flow field and temperature field on the microstructure and defects distribution of A356 is analyzed by ProCAST software. Simutaneously, the mold filling and solidification of the bottom gating and rotated solidification technology is simulated. Thus, the optimize process parameters obtained by calculating is pouring temperature 725°C, pouring times 21s, and preheating temperature of cylinder sleeve 450°C. Then, the cylinder is made under the condition of above parameters and the microstructure of the cylinder was observed. The results show that the microstructure and defects distribution which is simulated by ProCAST software are good agree with the experiments. Keywords：ProCAST; Aluminium alloy cylinder; Flow field; Temperature field;
Influence of Hot Deformation on Microstructure of Non-Quenching and Non-Tempering Pipe 36Mn2V Used in Oil Well
Authors: Fang Jian , Li Yang Hua , Xie Kai Yi , Zou Xi Yang , Zhou Meng Xiong , Yuan Ze Xi
Published: December 2011

The continuous rolling and sizing processes for producing non-quenching and non-tempering 36Mn2V steel pipes used in oil well were studied by the thermomechanical simulation test in this paper. The results showed clearly that the final microstructure was influenced by deformation temperature and stain applied. When continuous rolling temperature was controlled at 1050°C and strain at about 0.5 or above, dynamic recrystallization was completed and fine austenitic grain was obtained. When sizing temperature was controlled at 850°C or below and strain at about 0.2 or above, fine acicular ferrite was obtained with properties satisfying the requirement of the high quality pipe. The results of the study provided reliable data for the controlled rolling and sizing processes for the production of the 36Mn2V steel pipes.
Numerical Modeling of Heat and Moisture Transfer during Microwave Drying of Wood above FSP (Part I: The Model)
Authors: Yu Jian Fang , Wang Xi Ming , Hao Yi Nan
Published: December 2011

This study proposes a numerical model of heat and moisture transfer based on volume averaging theory according to the internal heat and moisture transfer phenomena and different transfer mechanisms above the fiber saturation point (FSP). The model takes into account the process of phase change and assumes that the driving forces of free water and water vapor are the different pressure gradients. Keywords: Wood; Microwave drying; Heat and moisture transfer; Volume averaging theory
Solidification Cracking Susceptibility of Alloy 52 Weld Overlay on 316L Stainless Steel
Authors: Chung Wei Chih , Tsay Lv Wen , Chen Chun
Published: December 2011

Nickel-based filler metals are widely used in the nuclear power industry for overlay welding of austenitic stainless steel components. However, solidification cracking in the weld metal has been observed in a number of cases after the initial deposit of Alloy 52 filler metal on the 316L substrate. In this study, Alloy 52 and its 52M modification were employed to perform overlay welding on 316L specimens. With proper welding heat input, no solidification cracks were observed in the transition zone of both weld overlays. As the heat input increased, solidification cracks could be found in the welds but was found to a lesser extent in Alloy 52M overlays. Nevertheless, such cracks could be eliminated by applying 309L filler metal as a buffer. This could be related to lower S and P contents in the buffer layer to reduce solidification cracking susceptibility of the subsequent weld passes. Additionally, the results of spot Varestraint tests also indicated that Alloy 52M had better solidification and ductility-dip cracking resistances than Alloy 52.
The Effect of Y on Aging Response and Mechanical Properties of Mg-Ho-Zr Alloys
Authors: Liu Bao Zhong , Liu Jiao Jiao , Wang Jian Li , Zhang Bao Qing , Zhang Zhi
Published: December 2011

Mg-10Ho-0.6Zr alloys with different amount of Y additions are prepared by metal mould casting method. The effects of Y content on microstructure, age hardening behavior and mechanical properties are investigated. Results show that all the as-cast Mg-10Ho-xY-0.6Zr alloys are mainly comprised of α-Mg matrix and Mg24(Ho,Y)5phase. With increasing Y content, grain size of the as-cast alloys is reduced. Age hardening response, Vickers hardness and mechanical properties are improved with the addition of Y. The maximum ultimate tensile strength (UTS) and yield strength (YS) are obtained in Mg-10Ho-3Y-0.6Zr alloy at peak-aged state, and the values are 215 MPa, 158 MPa at room temperature, and 144 MPa, 126 MPa at 250 °C, respectively. The improvement of the UTS is mainly attributed to the fine distributed quadrate-like β stable phase. Key words: Mg-Ho-Y-Zr alloy; Microstructure; Age hardening behavior; Mechanical properties
Study on Health Function of Cunninghamia lanceolata Biomass by TD-GC-MS
Authors: Ma Qing Zhi , Ma Dang Quan , Xiao Lu Yang , Liu Qi Mei
Published: December 2011

Cunninghamia lanceolata has been the dominated species of plantation forest in South China. However, the most products made from Cunninghamia lanceolata biomass are lower value added. In order to obtain top value-added products, health function of Cunninghamia lanceolata biomass were studied by TD-GC-MS. Relative content of each component was determined by area normalization. The main 40°С volatiles were 1-propanone, 2-amino-1-phenyl-(14.22%), benzene (11.17%), acetic acid (10.16%), cyclopentanecarboxylic acid, 1-(2-butenyl)-2-oxo-, ethyl ester, (e)-( 7.56%), 1h-cyclopenta [1,3] cyclopropa [1,2] b enzene, octahydro-7-methyl-3-methylene-4-(1-methylethyl)-(6.24%), etc. And the main 60°С volatiles were cedrol (29.65%), acetic acid (12.35%), cyclopentanecarboxylic acid, 1-(2-butenyl)-2-oxo-, ethyl ester, (e)- (7.78%), 1,6-cyclodecadiene, 1-methyl-5-met hylene-8-(1-methylethyl)- (6.11%), etc. So Cunninghamia lanceolata biomass had health function under indoor temperature. Keywords: Health function; Cunninghamia lanceolata; Biomass; TD-GC-MS