bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling of Anchors in Gravel Formation Using Discrete Element Method
Authors: Hsu Sung Chi , Lai Bo Jing , Hsu Wei , Lai Juir Ren
Published: February 2011

The subject of this research mainly focuses on the gravel formation along the western foothill of Taiwan. Numerical simulations are performed using discrete element method (DEM) based the software Particle Flow Code (PFC). Physical properties and internal friction angle of gravels are obtained from the three dimensional modeling of in-situ direct shear tests. The numerical experiments using PFC2D are used to model single-vertical anchor installed at shallow depths. The numerical results indicate that the failure range for the tension-type anchor is smaller than the range for compression-type anchor at the same bonded length and friction angle. The pullout resistance for the compression anchor is also greater than the tension anchor. Similar results have been obtained from the field pullout tests. The transmission of forces along the anchor is significantly affected by way of particle permutation with the anchor. If bigger size particles are piled around the anchor, the transmission of forces along the anchor will be faster and the affecting range of particles is also larger.
Mechanical Properties of Commercially Pure Titanium during Hot Compression
Authors: Zhang Yan Shu , Jin Quan Lin
Published: February 2011

Commercially pure titanium (CP Ti), grade II, is subjected to hot compression at temperatures ranging from 673 to 973 K with 50 K intervals and strain rates of 0.001, 0.01, 0.1 and 1s-1 up to 60% height reduction. By analysing work hardening rate vs. flow stress, the deformation behaviour can be divided into three groups, viz. three-stage work hardening, two-stage work hardening and flow softening. By plotting the data in a T vs. logε diagram, the present and previous data fall into three distinct domains which can be separated by two distinct values of the Zener-Hollomon parameter.
High Temperature Oxidation Behavior of (Ti, Al) C Ceramic Coatings on Carbon Steel Prepared by Electrical Discharge Coating in Kerosene
Authors: Li Guo Liang , Jie Xiao Hua , He Ling
Published: February 2011

Multi-component metal ceramic coating（Ti, Al）C was prepared on the 0.45% carbon steel by electrical discharge coating (EDC) in a hydrocarbon medium. The coating of the samples before and after oxidation was analyzed by different methods including X-ray diffraction (XRD), scanning electron spectroscopy (SEM) and energy disperse spectroscopy (EDS).The thermogravimetric technique was used to approximate the kinetics of oxidation of the coated and the uncoated samples.The results indicated that the thickness of the coating was about 20μm, and the composition of the ceramic coating mainly consisted of (Ti, Al) C and a little Ti3AlC. An oxide film with compact structure formed after 600°C oxidation for 200h, and it was mainly composed of Al2O3and TiO2, which inhibited further oxygen diffusion into the coating. The (Ti, Al) C ceramic coating possessed slow oxidation rate and high temperature oxidation resistance.
Corrected Diffusion Model of Chloride in Concrete and its Engineering Application
Authors: Xue Peng Fei , Mao Da Ling
Published: February 2011

A multi-factor diffusion model of chloride in concrete was formulated, in which the hypothesis of Fick’s Law were corrected through parameter definition. The values of the parameters in the model were given for practical applications according to pilot calculation and analysis of mass data. By using this diffusion model, three calculation methods of concrete structure service life were further deduced, it includes definite value method, probability performance based method and time-dependent reliability based method. The service life prediction for the approach bridge of Huang-pu Bridge was carried on by using various prediction approaches mentioned above. The results showed that: time-dependent reliability based method can consider randomness of chloride diffusion coefficient and the depth of concrete covering layer, and the stochastic characteristic of environment variable can be easily taken into account too. By adjusting the target reliability, the prediction results are consistent with those of the other two methods.
Research on the Stress and Strain Field and Wall Thickness in Power Spinning of Ellipsoidal Heads with Variable Thickness
Authors: Zhang Jin Hui , Yang He , Zhan Mei , Jiang Hua Bing
Published: February 2011

In this paper, a reasonable 3D FE model for power spinning of ellipsoidal heads with variable thickness has been established under ABAQUS/Explicit and validated. Then the variation of stress, strain and wall thickness during the process are obtained. Furthermore, the influence of the springback on stress, strain and wall thickness are gained with ABAQUS/Standard. The results show the following: (1) In the beginning, large stress, large strain and the thinning zone of wall thickness localize at the small contact zone below the roller; Then the zone extends into a ring and moves towards the position behind the roller; In the end, the ring transfers to the contact zone below the roller again and becomes uneven. The thinning zone is gradually impelled along the generatrix direction, and wall thickness is getting smaller and smaller. (2) The distribution of stress becomes more even after the springback, while the springback has little effect on the distribution of strain and wall thickness.
Research of New Type PAN-Based Carbon Fiber Pre-Oxidization Furnace and its Temperature Controlling Property
Authors: Xu Shu Qiong
Published: February 2011

A new type pre-oxidization furnace used for producing PAN-based carbon fiber has been developed. Practical operations showed that the furnace possesses characteristics of reasoanable design, higher temperature controlling precision and high hot efficiency. It is an ideal pre-oxidization furnace.
Simulation of Reflective Crack Propagation Path in Asphalt Overlay under the Partial Wheel Load
Authors: Yang Bin , Huang Qin Shou , Liang Ping , Xu Hua
Published: February 2011

Partial wheel load is one of the main causes that lead to shear-type reflective crack of asphalt overlay in the old cement concrete pavement. Based on the theory of fracture mechanics and finite element method, this paper focuses on the numerical simulation of the reflective crack propagation path in asphalt overlay under the partial wheel load. Calculation result and analysis show that reflective crack partially expands upwards at the side of wheel load under the effect of partial wheel load with a sequential increase of crack propagation length. As the crack propagation length increases, stress intensity factors grow rapidly in the early period, and then increase by degrees slowly and, in the later period, the amplitude grows increasingly. Stress and strain fields enhance as the reflective crack increases upwards and the crack propagation angle expands gradually with the increase of reflective crack propagation length.
Design and Analyses of Roof Structure in Hangzhou Grand Theater
Authors: Du Wen Feng , Zhou Zhi Yong , Wang Sheng Xiang , Yu Fu Dong
Published: February 2011

This paper deals with the issues involved during the design of a complex roof structure in the grand theater located at the city of Hangzhou, China. The complexity comes from the structural being of three reasons: long-span, complex structure and special figuration. To study the roof structure completely, researches on the mechanical properties of the structure are carried out in the paper. The nonlinear finite element method is used to analyze the geometrical nonlinear stability. Buckling and post-buckling analyses are performed to determine the load-carrying capacity of the perfect and imperfect roof structure. Meanwhile, the critical loads of the structure with different parameters are also discussed in this paper. It is shown that the effect of supporting stiffness originated from foundations and concrete structures to improve the critical load is evident. The buckling of the structure is a global collapse. With the temperature rises, the limited load-carrying capacity of the structure decreases obviously.
Numerical Study on the Large Deformation of Silicone Rubber Foams Based on Random Cell Models
Authors: Fan Zhi Geng , Chen Chang Qing , Hu Wen Jun , Niu Wei , Zhang Xue Mei
Published: February 2011

Two-dimensional (2D) random cell models composed of circular cells with different sizes are developed to simulate the microstructure of silicone rubber foams. The two-parameter Mooney-Rivlin strain energy potential model is employed to characterize the hyperelasticity of the solid of which the foams are made. Finite element method is used to simulate the large deformation of the foams. Predicted uniaxial compressive stress-strain curves exhibit universally three deformation regions: an initial linear-elastic response, an extended plateau region, and a final densification stage as cell collapsing. It is also found that with the foam relative density increasing, the initial linear-elastic region is found to extended, the buckling plateau section becomes indistinctive, and final densification stage is hastened.
Optimal Clamping Scheme of Thin-Walled Cavity Workpiece
Authors: Geng Shi Min , Wang Jun
Published: February 2011

The thin-walled cavity workpiece with insufficient rigid property is liable to deform during the machining process and the request of accuracy is very strict. The paper takes typical aeronautic aluminum-alloy for example, fixture is an important consideration in the operation. To reveal the influences of locating points, clamping sequence and loading ways on the distortion of thin-walled cavity part, finite element models were established to simulate the clamping operation. The result shows the preferable scheme is that the distance of the clamping locations are far each other, clamping forces are firstly applied on the surface with high rigid and all clamping forces are applied in many steps. The scheme can effectively control the deformation of clamp ,and furthermore improve the machining accuracy.
The Influence of Alloying Additives on the Machinability of Austenitic Stainless Steel
Authors: Tian Yong , Li Zhuang
Published: February 2011

In this study, non-lead machinable austenitic stainless steel was investigated through performing the machinability tests using a CA6164 lathe. The metallurgical properties, machinability and mechanical properties of the developed alloy were compared with those of the conventional austenitic stainless steel 1Cr18Ni9Ti. The results have shown that the inclusions were composed of MnS, Bi, CuO and Ti4C2S2 in the developed non-lead machinable austenitic stainless steel. Bismuth is an important factor to improve the machinability of austenitic stainless steel, and it has a distinct advantage over lead. The presence of alloying additives contributes to the improvement of the machinability of the developed austenitic stainless steel. The mechanical properties of non-lead machinable austenitic stainless steel exhibit a good combination of tensile strength and total elongation, despite the inclusion had a minor detrimental effect on them.
Numerical Simulation Analysis of Spinning Forming Process of Tubeless Steel Wheel on Technical Parameters
Authors: Bi Da Sen , Yang Guang , Chu Liang , Zhang Jian
Published: February 2011

Spinning is the main process of making the tubeless steel wheel, which is a key factor to the outline dimension and use performance. It offers reliable technology for manufacture and use of tubeless steel wheel. We make a list of experiment by number simulation to the spinning process of tubeless steel wheel using Deform-3D，and get the result which is that a well quality steel wheel can be formed under the condition of r=1,2rad/sec and f=0.7. It provide reliable basis for the manufacture of tubeless steel wheel.
Numerical Optimization Design on the Parameters of Double Ellipsoid Welding Heat Source
Authors: Zeng Zhi , Wang Li Jun , Li Xun Bo
Published: February 2011

The main objective of this study is to generate new understanding and improve computational method for optimization design on the parameters of double ellipsoid welding heat source. On the basis of Infrared measurement (IR), two optimization design methods, the zero-order method and first-order method, were combined to confirm the heat source parameters. The simulated thermal cycles, the weld penetration and the weld width were consistent to the experimental results with such corrected parameters. The effects of the parameters were analyzed by gradient evaluation method. It presents that as each of the parameters increasing, the peak temperature in the thermal cycle declines. Of all the three parameters, the sensitivities of the weld penetration and width with parameter c are great.
Influence of Turbulence Controller on Flow Mode of Molten Steel in Tundish
Authors: Ma Tian Fei , Liu Guo Qi , Yang Wen Gang , Yu Jian Bin
Published: February 2011

According to tundish for thin slab caster in a steel factory, 1:3 water modeling and numerical simulation were established. By measuring RTD(Residence time distribution) curves of fluid flow in tundish, real residence time, plug flow volume fraction and dead zone fraction were computed, influence of turbulence controller structure on flow mode of molten steel in tundish were studied. The results show that fluid flow in tundish can be improved, if turbulence controller has reasonable structure. A reasonable turbulence controller structure was obtained. Water modeling results agree with numerical computing results well.
Influence of Segmented Blank Holder for Rectangular Box Drawing
Authors: Li Xi Ning , Liu L.X. , Wang J.P. , Jiang C.Y. , Wang Z.Q.
Published: February 2011

Blanker holder force (BHF) is one of the important parameters in sheet metal forming process, which is loaded by blanker holder in order to avoid wrinkling. With the development of technology, segmented blanker holder is applied to complicated product forming in order to improve the parts quality. On the basis of analyzing the character of rectangle box forming, the blank holder was divided eight portions, including 2 long straight segments, 2 short straight segments and 4 corners, which each part can separately move. Then the forming simulation of the low carbon steel rectangular box with segmented constant BHF was conducted using orthogonal experiment and considering test conditions. After the results were analyzed according to the thinnest level of the parts, the influence of the segmented blank holder on rectangular box forming was obtained. It indicates that the segmented blank holder has the ability of the local control to sheet metal forming, and can effectively adjust material flow and the strain distribution.
Polymer Cement Waterproof Coating and its Properties
Authors: Fu Wen , Wang Li , Huang Jun Zuo
Published: February 2011

As a new environment-friendly waterproof material, polymer cement waterproof coating combines the rigidity of cement and the flexibility of polymer materials. The ratio of the liquid powder、the ratio of the C/P, the dosage of stuffing, the coating-forming additives, the defoamer were discussed to investigate their effect on the waterproof materials’ tensile performance and fracture elongation.
Survey and Trend of Rapid Heat Cycle Molding
Authors: Li Ji Quan , Jiang Shao Fei , Chen Chuan
Published: February 2011

This paper briefly introduced the principle of Rapid Heat Cycle Molding. Researches and applications of Rapid Heat Cycle Molding were reviewed, and heating method and mold structure were emphatically studied. At last the exiting problems and trend were proposed.
Effect of Position between Upper Die and Workpiece on Cold Rotary Forging
Authors: Han Xing Hui , Hua Lin
Published: February 2011

Cold rotary forging is an advanced but very complex incremental metal forming technology with multi-factors coupling interactive effects. The position between the upper die and the workpiece has a significant effect on the cold rotary forging process. In the current work, a 3D elastic-plastic dynamic explicit FE model of cold rotary forging of a cylindrical workpiece is developed under the ABAQUS software environment and its validity has been verified experimentally. On the basis of this reliable 3D FE model, the effects of the position between the upper die and the workpiece on the cold rotary forging process have been thoroughly revealed. The results show that with increasing the distance between the pivot point of the upper die and the centre of the workpiece, the deformation of the workpiece becomes more inhomogeneous and the maximum axial forging force and forging moment gradually increase. The results of this research not only provide valuable guidelines for the installation and adjustment of dies in the cold rotary forging process, but also help to better understand the deformation mechanisms of cold rotary forging.
Development of an Indirect Solid Freeform Fabrication Process Based on Stereolithography and Gelcasting for Ceramic Casting Molds
Authors: Wu Hai Hua , Fang Zi Fan
Published: February 2011

In this paper, an indirect solid freeform fabrication (ISFF) process was developed to rapidly fabricate ceramic casting molds by combining stereolithography with gelcasting technology. To realize this method, the stereolithography apparatus was used to fabricate a resin mold, and then aqueous ceramic slurry was cast into the resin mold and in situ polymerized to form a wet green body of ceramic casting mold. Freeze drying, pyrolyzing and sintering completed the manufacturing route. Finally, the ceramic casting mold with complex ceramic cores was obtained, and a car radiator with deep grooves was produced to verify the validity and feasibility of the method.
Numerical Simulation of Microstructure Evolution of Hot Forging
Authors: Ma Zhi Hao , Dong Xiao Lei , Yun Bing
Published: February 2011

The paper focuses on the research of using the coupled thermo mechanical analysis method of rigid viscoplastic finite element and the evolution of dynamic recrystallization to establish the calculation model coupling factors of deformation, heat conduction, dynamic recrystallization in the DEFORM, and on the hot-forging simulation of AISI4140. Through the simulation, it makes a valid prediction of dynamic recrystallization volume fraction and the grain size of recrystallized during the metal hot-forging process.
A New Axial Upsetting Process for Large Ingots with Large Ratio of Height to Diameter
Authors: Lan Jian , Li Cheng Ding , Qiu Yu Long , Hua Lin
Published: February 2011

To remove casting porosity and obtain smaller crystal grains, many large forgings need ingots to be upset axially with large ratio of height to diameter (H/D) greater than 3. But the ingots with large H/D are prone to buckling during upsetting process, and have non-uniform internal stress and strain distribution, cracks at barreling and other defects. A new axial upsetting process was proposed to handle these problems. Firstly, the research described deformation inhomogeneity and cracking tendency, and analyzed the causes of defects in the flat anvil upsetting process. Secondly, three two-stage upsetting processes were tried to improve the uneven deformation in the flat anvil upsetting, which applied symmetrical spherical convex die, conical convex die and multi-line sweeping concave die respectively in the first stage, and used flat anvils in the second stage. The effect of the die surfaces on constraining those defects was analyzed. Finally, three three-stage upsetting processes were suggested to take advantages of different die surfaces to stabilize the process. It was observed that the upsetting had better result from using conical convex die and multi-line sweeping concave die in the first stage, conical convex die and flat anvil in the second stage, two flat anvils in the third stage. The new axial upsetting process could improve the quality of the large forgings with more uniform deformation and less barreling.
Influences of Material Thickness on Hole-Flange Forming Limitation
Authors: Thipprakmas Sutasn , Phanitwong Wiriyakorn
Published: February 2011

In recent years, the hole-flanged components are not only fabricated for a thin sheet metal but they are also increasingly manufactured for a thick sheet metal especially in the automotive industry. However, most of the past researches have been studied the hole-flanging of thin sheet metal. In this study, the influences of material thickness were investigated using the finite element method (FEM) and laboratory experiments. Based on the stress distribution analysis, as the material thickness increased and the hole-flange forming ratio decreased, the effects of bending feature and the material stretching increased which resulted in the easy crack formation. The relationship between material thickness and hole-flange forming limitation was also investigated. In addition, the poor flatness on flange edge increased as the material thickness increased. The FEM simulation results showed the good agreement with the experimental results.
Research of Numerical Simulation Method in Two Pass Deep Drawing Forming of Sheet Metal
Authors: Han Zhi Ren , Fan Fu Xia
Published: February 2011

Numerical simulation is of great importance in sheet metal multistage deep drawing forming, optimizing mould design and improving mould research and development capability. Now researchers have proposed the numerical simulation general steps of multistage deep drawing, but there are still many problems to be resolved. This paper, comprehensively considering the two important factors of influencing the accuracy of the numerical simulation, introduces the numerical simulation simplified steps of two pass stamping forming. Results show that this new method is effective and successful in simulating two pass deep drawing forming, and the simulation results are more reasonable.
Warm Compacting Behavior of Pure Titanium Powders
Authors: He Shi Wen
Published: February 2011

Warm compacting behaviors of pure titanium powders were studied. The results show that warm compaction can be applied to titanium powders. The green densities obtained through warm compaction are generally higher than obtained through cold compaction at the same pressure. The optimal warm compacting temperature is about 140 . At the compacting pressure of 500 Mpa, the ejection force of titanium powders through warm compaction is 32.4% lower than through cold compaction. At the same pressure, the effective compression force through warm compaction is bigger than one through cold compaction. In addition, the densification mechanism of warm compaction was discussed.
LY11 Alloy Flat Bar Produced by Continuous Semisolid Extruding Extending Forming Process
Authors: Wang Shun Cheng , Qi Wen Jun , Zheng Kai Hong , Wen Jing Lin
Published: February 2011

Continuous semisolid extruding extending forming process was adopted to produce LY11 alloy flat bar. The forming process, metal flow behavior in die cavity and microstructure and mechanical property of flat bar were investigated. It is shown that the LY11 alloy flat bar with transverse section of 10×50 mm and with good surface and fine equiaxed grains can be obtained by the continuous semisolid extruding extending forming process with melt pouring temperature of 770～780°C. The metal streamlines show that the semisolid slurry fills the die cavity in radiation manner and moves forward layer by layer and the velocity of slurry flow in the central area of die cavity is the maximum, and then decreases gradually from the center to side of die cavity. The tensile strength and elongation of flat bar with T6 heat treatment are 420.5 MPa and 14.2%, respectively.
Effect of Rare Earth (RE) La on Solid Solution of Second Phase Particle and Austenite Grain Growth in Steel Containing High Niobium
Authors: Song Wen Zhong , Fang Qi , Ren Hui Ping , Jin Zi Li , Chang Hui
Published: February 2011

The solid solution of the second phase particle and austenite grain growth behavior of the high niobium-containing RE steel was studied by mathematical calculation and extraction replica technique. The purpose of the study was to investigate the effects of Rare Earth La on austenite grain growth and propose an empirical equation for predicting the austenite grain size of RE steel. Austenite grain grows in an exponential law with the increase of heating temperature, while approximately in a parabolic law with the increase of holding time. Results show that the RE steel has good anti-coarsening ability at elevated temperatures. When soaking temperature is lower than 1250°C , AGS and growth rate are small for high niobium steel, but soaking temperature is lower than 1220°C , AGS and growth rate are small for RE steel. RE La can promote solid solution of second-phase particles Nb(C, N), the solution temperature decrease 30°C than high niobium steel.
Co-Deposition of Binary Particles during Slip Casting Process
Authors: Li Yuan , Qiu Yue
Published: February 2011

Co-deposition of silicon carbide particles and carbon (or carbon sources) particles is essential for preparation of reaction bonded silicon carbide (RBSC) products by slip casting. The way of co-depositing of silicon carbide particles and carbon particles during slip casting process, and the influence of composition of raw particles on particle co-depositing in green bodies were studied. The experiment results show: 1.Co-deposition of binary particles is greatly affected by particle size distribution, and large proportion of rigid SiC particles increases the difficulty in demoulding procedure because of small shrinkage; 2. Dispersants in deposited cake trend to enrich at the surface in contact with mould wall, while this enrichment of dispersant has little effect on mechanical performance of RBSC products; 3. Sharp edges on surface of raw particles could result to friction among particles, which afford strength to green bodies but prevent particles packing more closely.
Effects of Continuous Extrusion on Microstructure Evolution and Property Characteristics of Brass Alloy
Authors: Li Bing , Li Chun Hai , Yao Xiang Jun , Song Bao Yun
Published: February 2011

The continuous extrusion process would refine the microstructure effectively and increase the formability and properties of extrusion products, without preheating and post-mechanical treatment. During the continuous extrusion operation the microstructure of brass alloy significantly influences formability and properties. So the microstructure evolution rules of brass alloy during the whole continuous extrusion process were analyzed, and the hardness changing laws of the extruded brass alloy were also researched in this paper. By observing the microstructure evolution at different regions, the evolution rules of microstructure and properties of the continuous extrusion brass alloy were obtained. It was found that the dynamic recrystallization occurred at the right-angle bending region, which was proved by the hardness evolution of the extruded brass alloy. Therefore, it is feasible to control the properties of the extruded products by concentrating the right-angle bending region. This work gives the researching foundation of low formability materials based on continuous extrusion operation.
Drawing Properties of Modified Polyamide 6 Fibers
Authors: Yeh Jen Taut , Wei Wei , Tsai Fang Chang , Lai Yu Ching
Published: February 2011

The drawing properties of the modified PA 6 (MPA) fiber specimens prepared at varying drawing temperature were systematically investigated, wherein the MPA resins were prepared by reactive extrusion of PA 6 with the compatibilizer precursor (CP). At any fixed drawing temperature, the achievable draw ratio (Dra) values of MPA as-spun fiber specimens increase initially with increasing CP contents, and then approach a maximum value, as their CP contents are close to the 5 wt% optimum value. The maximum Dra values obtained for MPA as-spun fiber specimens prepared at the optimum CP content reach another maximum as their drawing temperatures approach the optimum drawing temperature at 120 °C. The tenacity and birefringence values of PA 6 and MPA fiber specimens improve consistently as their draw ratios increase. Similar to those found for their achievable drawing properties, the ultimate tenacity and birefringence values of MPA fiber specimens approach a maximum value, as their CP contents and drawing temperatures approach the 5 wt% and 120 °C optimum values, respectively. Investigations including Fourier transform infrared, melt shear viscosity, gel content, thermal and wide angle X-ray diffraction experiments were performed on the MPA resin and/or fiber specimens to clarify the optimum CP content and possible deformation mechanisms accounting for the interesting drawing and ultimate tensile properties found for the MPA fiber specimens prepared in this study.
Contrast Studies on the Solar Drying Schemes of Eucalypt Timber
Authors: Gan Xue Fei , He Zheng Bin , Yi Song Lin
Published: February 2011

This research takes Eucalyptus grandis×E.urophylla timber as materials, making them drying with five kinds of schemes. Five experimental schemes are taken as follows: natural air drying, solar energy with storing heat, solar energy without storing heat, solar energy with electric heating during the day, solar energy during the day and electric heating during the night. Experiments have found that: in normal sunny weather conditions, the temperature of solar drying completely satisfies eucalyptus wood drying demand. Energy saving ratio is above 60%; In weaker solar radiation intensity conditions, drying needs to use auxiliary power. Energy saving ratio is about 47.1%. The period of Solar drying is 3/4~1/3 shorter than that of natural air drying. Dry defects were obviously reduced. It has the good prospects for development.
Effect of the Surfactant Concentration on Sinking Electric Discharge Machining Performance with Water-in-Oil Emulsion as Dielectric
Authors: Zhang Yan Zhen , Liu Yong Hong , Ji Ren Jie , Cai Bao Ping
Published: February 2011

In this paper, the EDM performance of water-in-oil (W/O) emulsions dielectric with different surfactant concentration is investigated by correlated to its physical properties, such as viscosity and droplets size, which is predominantly determined by the surfactant concentration. Experimental results show that the stability of the W/O emulsions increases with increasing surfactant concentration, whereas the EDM performance deteriorates with increasing surfactant concentration. So, taking a comprehensively consideration of the emulsion stability and EDM performance, the concentration of surfactant must be appropriately selected.
Grinding Performance of Porous Diamond Wheels on Different Materials
Authors: Dai Qiu Lian , Luo Can Bin , You Fang Yi
Published: February 2011

In this paper, metal-bonded diamond wheels of different sized abrasive grain with different porosity were fabricated. Grinding experiments with these wheels on three kinds of materials were carried out under different grinding conditions. Experimental results revealed that wheel with high porosity (38%) had smaller grinding forces and specific energy than the one with a medium porosity (24%) on grinding G603. However, on grinding harder materials like Red granite or ceramics of Al2O3, the wheel with 38% porosity had bigger grinding forces and specific energy than the wheel with 24% porosity. Both wheels exhibited good self-sharpening capability during the grinding process of G603 and Red granite, but on grinding ceramics of Al2O3 the wheel with 38% porosity displayed in dull state during the grinding process . With the same porosity, the grinding forces of the wheel with a grain size of 230/270 US mesh were lower than the one with a grain size of W10 when grinding Red granite and ceramics of Al2O3. However revising results were obtained on grinding G603.
Study on Cutting Process of Manual SHS Cutting Technology
Authors: Wu Yong Sheng , Wang Jian Jiang , Xin Wen Tong , Li Zhi Zun , Qu Li Feng
Published: February 2011

Cutting process of manual self-propagating high-temperature synthesis (SHS) cutting technology was studied based on industrial Q235 steel specimen and cut material of cutting pen. Through research of kerf and analysis of manual SHS cutting process, three zones of base metal is formed under the cutting pen process: molten zone heated directly by cutting pen, the common active zone of cutting pen , metal flow and slag flow, metal flow and slag flow heating zone. Its cutting process can be divided into four inter-related stages as follows: the formation stage of the molten pool, the increasing stage of the pool penetration, the stage of slag blowing off and kerf formation and then the formation stage of a new pool. The way to improve efficiency of manual SHS cutting technology is proposed at the end.
Welded Joint Nonpenetration and Slag Inclusion Evaluation Based on MMM Signal Characteristic
Authors: Xing Hai Yan , Zhang Li Hong , Xu Cheng , Chen Xin Yu
Published: February 2011

The metal magnetic memory (MMM) technology, a new nondestructive testing (NDT), has potentials of quantitative evaluation on welded joint defects. This paper investigates MMM signal quantitative characteristic of welded joint defects. Steel Q235 welded joint specimens, prefabricated with nonpenetration and slag inclusion, have been scanned by MMM testing instrument at 0kN, 150kN and 230kN tension loads on tensile machinery. For the nonpenetration specimens, MMM peak amplitude ΔHp and the peak width D adds with the increasing of tensile load, but gradient K varies a little. As for the slag inclusion specimens, the ΔHp and K enhances along with tensile load increasing, but the D varies a little. The X-ray testing results at 0kN, 150kN and 230kN tension loads show the validity of MMM signal characteristic. This means the feasibility of the weld qualitative and quantitative evaluation based on MMM method.
Effect of Electrode Force Change on Spot Weld Quality of AHSS Using Servo Gun
Authors: Liang Cai Ping , Liu Xiao Hang , Bai Yue Wei
Published: February 2011

Due to bad welds including small button, weld expulsion, and weld whisker etc., it is studied that the effect of constant and variable electrode force with servo gun on the weld quality of high strength steels with different thickness and materials. The results show that the electrode force plays an important role in resistance spot welding of AHSS as well as that of mild steels. Under the same welding current and time, better welds with higher tensile shear strength and larger nugget size can be obtained by optimizing electrode force curve using servo gun. The solutions could supply reference to study the prospect of servo gun in the joining of high strength steels.
Effects of Wire Rotating Frequency on Metal Transfer Process in Rotating Arc Narrow Gap Horizontal GMAW
Authors: Guo Ning , Han Yan Fei , Jia Chuan Bao , Du Yong Peng
Published: February 2011

The metal transfer process with different welding parameters in rotating arc narrow gap horizontal welding is successfully observed by the high-speed photography system. The effects of wire rotating frequency on metal transfer process in rotating arc narrow gap horizontal welding are novelly explored. The metal transfer with different wire rotating frequency presents different modes. The results indicate that the droplet transfer has stable process with the rotating frequency of 5-20 Hz. And the weld formation is quite shapely. But with the high rotating frequency of 50 Hz, the metal transfer process is not acceptable and the weld formation is very pool. Metal transfer process is one of the most important factors of effecting the weld formation in rotating arc horizontal welding process besides the molten pool behavior and welding thermal circles.
Finite Element Analysis for Temperature Field of Laser Remelting Plasma Sprayed Ni-Based Gradient Coating on Ti6Al4V Alloy Surface
Authors: Guo Hua Feng , Zhou Jian Zhong , Sun Tao , Li Ju Li , Li Zhi
Published: February 2011

In order to acquire evolution law of temperature field of laser remelting plasma sprayed Ni-based gradient coating on Ti6Al4V alloy surface，the effects such as heat conduction, heat radiation, heat convection ,phase change and materials highly non-linearity on coatings and substrate are taken into account comprehensively, and a 3D finite element model(FEM) of multi-tracks laser remelting temperature field is established. The analysis results show that mechanical bonding between coatings and substrate change into metallurgical bonding on present processing parameter，the depth of alloy belt vary in each scanning track and the average depth of alloy belt become deeper gradually with the increment of scanning lines. Temperature changing regular of different points on scanning tracks along scanning direction is similar. Temperature become higher and higher in succeeding scanning tracks due to the heat accumulation effect in laser remelting process. The cooling rate on the mid-points of each scanning track reaches 1200 /s above. The thermal gradient from coatings to substrate along Z direction is absolutely predominant compared with that along X,Y direction, so heat dissipates mainly along the direction normal to substrate which help to crystal grain grown preferentially.
Effect of Magnetic Field on Microstructure and Properties of Magnesium Alloy Welded Joint with GTAW
Authors: Su Yun Hai , Liu Zheng Jun , Liu Duo
Published: February 2011

In this investigation, in order to research the influence of magnetic field on microstructure and properties of magnesium alloy welded joint, the AZ31 magnesium alloy plates which was 5mm were welded by GTAW under longitudinal magnetic field. The tensile test, hardness test and SEM were taken place to analyze the properties and microstructure of welded joint under different magentic field parameters. The acting mechanism of magentic field on welded joint was studied. The results show that: External magnetic field can improve the properties of magnesium alloy welded joint which is welded by GTAW. The optimal mechanical property will be obtained when Im=2, f=20Hz, which the ultimate tensile strength is 231Mpa and the micro-hardness is 76.2HV.The magnetic field can produce electromagnetic stirring, which can refine crystal grain through breaking the pine-tree crystals with proper magnetic field current and frequency. The properties of welded joint will been improved by these fine crystal grain.
Optimal Design for Fe-Cr-C Hardfacing Alloys with Anti-Wearing
Authors: Yuan Tao , Luo Zhen , Wang Rui
Published: February 2011

In this paper, to obtain hardfacing alloys with Anti-wearing，nine kinds of low-hydrogen type coating are designed with orthogonal optimization method and carbon, chromium, erbium and cerium are taken as four factors. The mechanical properties of each hardfacing layer are tested and the microstructure is analyzed. The optimal dosage of the four elements is found by R/S analysis method. There is no crack in continuous surfacing with the electrode prepared with optimal formula, the wear resistance of the corresponding hardfacing layer is good while the hardness reach to 57.9HRC, the microstructure is martensite, a small amount residual austenite and dispersed carbide.
Applications of Piezoelectric Materials
Authors: Badr Basem M. , Ali Wahied G.
Published: February 2011

In this paper, the different applications of piezoelectric material (PZT) are surveyed such as: actuators, motors, transformers, sensors, and benders. The operation concept, advantages and disadvantages of these types are explained, that drive the suitable application of them. Moreover, the electrical and mechanical features of piezoelectric material are presented. These features are dynamic behavior, operation voltage, maximum force, and temperature effect. There are different piezoelectric material types such as ferroelectric materials and ferroelectric polymers that are presented and a comparison between them is achieved.
Effect of Carbon Fiber on Composites
Authors: Wang Xue Zheng , Song Xiao Rui
Published: February 2011

In this study, the hybrid fiber prefabricated parts composed of short Al2O3 and carbon fiber are made successful by vacuum subatmospheric shaping method. The ZLl09 alloy reinforced by the prefabricated Al2O3 and carbon fiber are prepared by squeeze casting method with fiber contents. The effects of carbon fiber on fraction and wear properties of the hybrid composites with fixed Al2O3 fiber volume fraction 10% were investigated.
Effects of the Processing Parameters on the Forming Quality of Stainless Steel Parts by Selective Laser Melting
Authors: Wei Qing Song , Zhao Xiao , Wang Li , Li Rui Di , Liu Jie , Shi Yu Sheng
Published: February 2011

Selective Laser Melting (SLM) can produce high-performance metal parts with complex structures. However, it’s difficult to control the processing parameters, because many factors involves. From the perspective of the molten pool, the study focuses on the effects of processing parameters, including scanning speed, laser power, scanning space, layer thickness, and scanning strategies, on the surface quality, the balling effect, the density of SLM parts, by conducting experiments of single track, single layer and block forming. The results show that the quality of the molten pool is affected by laser power and scanning speed. Scanning drove in the strategy of “jumping and turning”，a smooth surface and a less balling effect will be obtained. The thicker the powder layer is, the lower density will be obtained. The optimal parameters from series of experiments are: laser power of 98W; scanning speed of 90mm/s; scanning space of 0.07mm; layer thickness of 0.1mm; and scanning strategy of “jumping and turning”.
Advanced Monitoring of Tool Wear and Cutting States in CNC Turning Process by Utilizing Sensor Fusion
Authors: Tangjitsitcharoen Somkiat , Rungruang Channarong , Pongsathornwiwat Narongsak
Published: February 2011

As the intelligent machine and manufacturing system plays an important role in the near future, the monitoring system in turning process is required to improve the productivity during the cutting process. Hence, the aim of this research is to propose and develop the in-process monitoring system of the tool wear and the cutting states of chip and chatter for the carbon steel in CNC turning process by utilizing the sensor fusion which are the force sensor, the sound sensor, the accelerometer sensor and the acoustic emission sensor. Their signals have been integrated via the neural network with the back propagation and the pattern recognition technique to monitor the tool wear and detect the cutting states which are the continuous chip, the broken chip and the chatter occurred. The experimentally obtained results showed that the in-process monitoring system proposed and developed in this research can be effectively used to estimate the tool wear level and identify the chip breaking and the chatter with the higher accuracy and reliability.
Microstructure Formation during Unidirectionally Solidified Pb-Bi-Sn Tenary Quasi-Peritectic Alloy
Authors: Hu Xiao Wu , Yan Hong
Published: February 2011

In order to investigate the microstructure formation resulted from quasi-peritectic reaction in Pb-Bi-Sn ternary alloy, specimens were directionally solidified with a constant temperature gradient (G=18 K/mm) and the growth velocities ranging from 0.5 μm/s to 10 μm/s. Experimental results indicated that a microstructure, which is composed of the residual primary α phase (Pb-rich solid solution), peritectic β-(Pb7Bi3) phase and Sn-rich solid solution phase was observed. Transition from primary α-cell to primary α-dendrite took place with the increasing growth velocity. The rod-like eutectic was observed in the inter-cellular region under low growth velocity. Detail analyses were adopted to identify the phases and determine the phase compositions, respectively.
Metastable Phase in Undercooled Fe-Co Alloy
Authors: Liu Ning , Yang Gen Cang , Liu Feng
Published: February 2011

Metastable phase was observed in as-solidified microstructure of undercooled Fe-Co alloy, provided that the initial undercooling (T) of the melt exceeds the critical value. On this basis, the forming mechanism and stability of metastable phase were investigated. The forming mechanism of metastable phase in undercooled Fe-Co alloy was concluded as cooperative effect of “competitive nucleation—remelting—extensive growth—incomplete solid-state transformation” in this work. With the increase of annealing time, the number and dimension of metastable phase decreased at the same time. Moreover, metastable phase was transformed to stable phase completely when annealing time increased to three hours.
Study on Defects of A356 Aluminum Alloy Wheel
Authors: Zhao Wei Min , Zhang Liang , Wang Zhi Feng , Yan Hong Ji
Published: February 2011

This paper studied the effects of inclusion and slag on properties of a die cast A356 alloy wheel. The result showed that the rate of defect is important for the mechanical properties. The tensile strength and extension was not dropped but the rate of defect is increased about 2%. The variation trend of tensile strength and extension is linear, while the area of porosity on tensile fracture is between 2% and 6%. However, the tensile strength and extension was dropped with the increasing rate of defect. The variation trend of mechanical properties of the sample with inclusion is stable, but the sample with slag is not stable. The mechanical properties of samples with inclusion are drastically changed, while the rate of defect is increased. The mechanical properties of samples with slag are smoothly. The EDS analysis indicated that the defects consist of Al-Ti-B compound, α-phase (Al12FeSi), β-phase (Al9Fe2Si2) and Al2O3. These oxides form the compact composite oxide film expand into first cracks. The fracture mode of sample with defects is brittle fracture. The values of the Secondary dendrite arm spacing (DAS) in the inclusion and the matrix are the same, while the values of DAS in the slag and the matrix are different.
Effect of Ce2S3 Powder Addition on Morphology of Graphite in Cast Iron
Authors: Zhang Suo Mei , Wang Zi Dong
Published: February 2011

In this paper pure carbon, pure iron and single crystall silicon were firstly loaded into a pure graphite crucible to obtain a hypereutectic Fe-C melt by carburizing at high temperatures. The powder Ce2S3 was added to the melt with different proportion under the same process conditions and cast iron samples were obtained. The graphite morphology of the samples was observed under optical microscope. Then matrix of the samples was etched by electrolysis way. At last the non-ferrous residue gathered from the surface of cast iron sample after electrolysis process was calcined and analysed with BEI and EDS to find the trace of Ce2S3. The results showed that the powder Ce2S3 was really added into the melt but did not make any change in graphite morphology.The only effect of Ce2S3 was to make the amount of graphite increase slightly.All results of this paper indicat that the additive Ce2S3 is only the base for graphite flake to precipitate but is not a sufficient condition for graphite to nodularize.
Simulation of Facet Dendritic Shape of Isothermal Alloy in a Forced Flow by Phase Field Method
Authors: Chen Zhi , Chen An Qi , Li Feng , Li Yang , Song Qing Jun , Kong You Chao
Published: February 2011

Numerical simulation based on a new regularized phase field model was performed to describe the dendritic growth of an isothermal alloy with a strong anisotropy in the presence of a forced flow. These results indicate that a crystal grow into an equiaxial facet dendritic in the absence of a forced flow and into an asymmetrical facet dendritic in the presence of a forced flow. With increasing a flow velocity, the tip steady velocity of upstream dendritic arm increases, that of the downstream arm decreases, and that of the perpendicular arms increases at first, and then decreases, the perpendicular arms gradually grow toward the incoming flow direction. In the certain range of anisotropy parameter, when γ is larger than 0.14, dendritic tip steady velocities in all direction are expected to reach their own saturation values. In addition, the effect of a compound forced flow on an isothermal facet dendritic is similar to experimental results.