The objective of this study is to develop a new method of mechanical fastening using friction stir forming technique. Trials with friction stir cladding were carried out on a-modified milling machine. Grooved carbon steel plate has been successfully clad with aluminum alloy by friction stir technique.

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Friction welding of 5052 Aluminum alloy similar material was carried out in order to examine the effects of deformation heat input and upset loss in the upset stage on the joint performance such as tensile strength. As the results, it was made clear that the deformation heat input in the upset stage was a dominant factor for controlling the friction weldability, increasing the deformation heat input in the upset stage caused an increase in the tensile strength of the weld joints and joints of stable-high tensile strength was obtained with 350J/S or more deformation heat input, and increasing the upset loss caused an increase in the tensile strength of the weld joints and joints of the stable-high tensile strength was obtained with about 7mm.

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Trials with friction stir welding of high-strength aluminum alloys were carried out on a modified milling machine. The results of friction stir welding 2017, 2024, and- 7075 alloys were discussed in terms of weld ability and weld strength.

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On Plastic flow behavior of Al at the Al-Ceramic friction-welded joints, the coupled deformation and heat flow analysis by finite element method was conducted. In the temperature field, it was demonstrated that the temperature increased at first on the friction surface, where the temperature in outside became higher than that in center. With the frictional time increasing, temperature increased whole site in Al. The deformation of Al became larger near the friction surface, and on the different welding conditions, the size of deformation was changed. In the plastic flow field, the flow direction was changed from the vertical direction to the friction surface to the parallel direction near the friction surface.

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Friction welding of Cu to 1050 aluminum alloy, Cu to S15CK carbon steel, and SUS304 stainless steel to 6061 aluminum alloy were carried out in order to examine the effects of deformation heat input in the upset stage and the upset loss on the joint performance such as tensile strength. As a result, it was made clear that the deformation heat input in the upset stage and the upset loss were not a factor for evaluating the friction weldability, becase of formation of excessive intermetallic compound when the friction time was long.

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The interface layer was observed with theultrasonic method during bonding process. The experiment was performed at about 180 ℃ with a waveguide. The waveguide of 80 mm in length and 15 mm in diameter of waveguide was fixed between the ultrasound probe and the bonding material. A copper plate was used as substrate and the SnBi alloy as solder material.. The immersion method was applied in this experiment, with grease as medium. The ultrasound data was compared to the observed interface layer through the optical microscope. The analysis in frequency domain was also performed.

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The technique of ultrasonic welding has been successfully applied to metal sheets, which can be welded to other metallic materials such as aluminum and copper etc. Those welding techniques can be considered for possible application where the welding is achieved at a low temperature or by short welding time of a thin surface layer followed by ultrasonic welding. For example, the ultrasonic welding of Cu/Fe could be finished under the condition of amplitude of 30μm of-ultrasonic horn top, welding pressure of 12MPa and required duration of 1.0s. Since the ultrasonic vibration cleans the contact surface, a surface treatment prior to the welding is not necessary.

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Directed Plasma Fabrication (DPF) is a rapid tooling process that is based on controlled deposition of molten powder particles according to computer-controlled patterns. It makes fully dense, near net shape metal components without molds or dies, and without forming, pressing or forging systems. Experimental works were carried out using conventional low current Plasma Transferred Arc Welding system, and metallic powder was stellite #21. Cylindrical shapes are successfully deposited as dimensions with 2.5-4.2 mm wall thickness. The key factor is the melting efficiency M, which is defined as the ratio of given heat input into base metal and required heat input to melting of deposited metal. Other one is the non-dimensional "operating parameter n" which is proposed by Christensen. As the conclusion, better" deposition efficiency is obtained in case of lower melting efficiency M, this means shorter arc length and slower traveling speed-when the same plasma current conditions are applied.

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This paper describes a new method for practical superplastic gas blow forming. The method consists of conventional forming processes except using Gas Generants as apressure source instead of inert or air gas blowing. When the temperature reaches at specific range, Gas Generants can decompose by itself and some gasses come out. Then any increase in temperature up to superplastic range may produce a dilatational work for gas blow forming. Alternative application to making of hollow structural truss components by using Gas Generants and hot roll bonding simultaneously can be illustrated also.

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In cast-in bonding, insert may melt and be damaged by excessive heat supply from the molten metal. To reveal the conditions of insert melting, two experiments were performed and the solidification and melting transient process was analyzed by the finite difference method. Mild steel and ductile cast iron bars were dipped into gray iron melt held at three temperatures. Cast-in insertion experiment on the same materials with various diameters was also performed. The experiment and the analysis showed that the melting of ductile cast iron bars was determined by heat transfer. The melting of mild steel is determined by the carbon diffusion, because increasing carbon concentration and decreasing of melting temperature are necessary for mild steel to melt.

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The arc welding remains many realms of the unknown in spite of being available widely in various fields of the industry. It is important to investigate the phenomena of the welding in order to improve the welding method and the automation of welding. GTAW is superior in the smooth of the bead and the reliability to other welding method, but it takes considerable time to weld because of low penetration. Though A-TIG is suggested to solve this problem, the convection mechanism in the molten pool is not revealed. In this study, the welding images are taken by high-speed camera and the convection on the molten pool is analyzed by image processing.

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In order to develop joining methods maintaining mechanical strength and superconducting property, YBCO bulk superconductors were joined using YbBCO, which had lower peritectic temperature than YBCO, added Ag_2O as interlayer. As results of joining tests under such conditions that Ag_2O content added to YbBCO was 0〜44mass% and that joining temperature was 940℃〜1020℃, the joint strength increased in accordance with the joining temperature increase. Critical current density showed maximum value in case using the YbBCO interlayer added 10〜30mass%. Because of the boids made at the joint, strength of joint was inferior to that of matrix, however, it was suggested that joint properties could be improved by selecting the joining time and pressure properly.

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In order to clarify the effect of surface conditions such as the oxide layer on the hydrogen permeation through the welded area of stainless steel, the permeability of stainless steels including welded area with the oxide layer which was made by heating in air was investigated. Permeation tests were conducted in such conditions as stainless steels with oxide layer only on high-pressure side where hydrogen gas was filled, or only on low-pressure side, or on the both sides. Permeability coefficient of welded stainless steels with oxide layer was different from stainless steels without oxide layer. Especially the permeability of the specimen with oxide layer on high-pressure side increased. This suggested that the permeation was considerably accelerated by adsorption of hydrogen gas on the oxide layer of the specimen.

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The carbon steel pipes for ordinary piping whose joints apt to have steps and stress concentration because of low accuracy for diameters and thickness, were pressure-welded using brazing filler by high frequency heating. Effect of the fillet produced at the step which is made by brazing filler extruded from the interface of joints on the joint strength, was examined by tensile tests and numerical analysis. According to tensile test, the strength of joints increased as fillet enlarged. It was confirmed by SEM/EDS analysis that brazing filler was extruded from the interface of joints, and different size of fillet was produced in accordance with the thickness of brazing filler. It was revealed that brazing filler filled the step and that the fillet relaxed the stress concentration to increase the strength of steel-pipe joints made by pressure welding using brazing filler at the joint interface.

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It is investigated that the effect of the grain size on the scale-dependence of fractal dimension for the fractured surface of steel. The effect is considered to appear for the fractured surface of diffusion-bonded steel joint. In this research, the fractured surface of cupper-brazed steel joint was analyzed, whose texture was free from the effect of grain size. The contribution of brazing filler thickness to the scale-dependence of fractal dimension was also discussed. For the each fractured surface of cupper-brazed steel joint, the scale-dependence of fractal dimension did not appear clearly, but the fractal dimension increased up to 2.0 for the larger scale than the correlation length similar to the brazer filler thickness. As conclusions, the texture with the effect of grain-size could show the scale-dependence in fractal dimension. And for the fractured surface of brazed joint, the texture could deal as typical ductile surface at the scale range smaller than the brazing filler thickness.

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Diffusion-bonded stainless steel joint apts to fracture brittlely in spite of its enough tensile strength comparable to the base metal. In order to clarify the causes, fractal analysis of the tensile fractured surface was applied under various bonding conditions. As changing the bonding conditions, the shape and distribution of faults such as voids and inclusions left on the bonding surfaces were varied as well as the shape of grain boundaries. These caused the change in fractal dimension variously. Because the fractured surface looked like brittle in macroscopic and ductile in microscopic, the fractal dimension was affected by its observing scale. It was verified that the microstructure of fractured surface was well characterized by its fractal dimension, and that fractal analysis was helpful in solving the problem of diffusion bonding.

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This paper describes the effect of die semi-angles on the extrudabirity of AZ31B magnesium alloy. There were not very much change of extrusion load and tensile strength under die semi-angle 30° ,45° ,60° to 90° . And the surface roughness of the extruded rods without small, of die semi-angles may be little more similar to that of roughness than that of large die semi-angle. It became clear that it can not be obtained a good surface appearance with the 90° die because of the surface cracks.

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To form Al-Ni intermetallic compound, it is thought effective that pressure die-casting process of slurry is carried out under semi-solid condition. The preforms, which were compacted with Al-42mass%Ni mixed powder, were heated at temperature range below and above the combustion synthesis temperature to form the slurry. Structure of products diecast under semi-solid condition consisted of Al_3Ni_2, Al_3Ni phases and α-Al-Al_3Ni eutectic structure. The volume fraction of Al_3Ni phase increased while Al_3Ni_2 phase decreased, as die-casting temperature rose. The volume fractions of Al_3Ni phase and eutectic structure of the product diecast at 973K were 40 and 58%, respectively.

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Mechanical alloying (MA) for powder mixtures of Ni-33mol%Al and Ni-33mol%Al-lmol%B has been carried out at various milling times. The obtained MA powders induced combustion synthesis in both atomospheres of the air and vacuum heating. The: reactive MA powders were consolidated at temperatures as low as possible by hot pressing. The obtained results showed the formation of intermetallic compounds such as NiAi and Ni_3Al, so that the combustion synthesis (reaction sintering) was considered to occur during the consolidation, but the densification was insufficient in this experiment.

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Tensile fracture behavior of two dimensionally reinforced Si-Ti-C-O fiber bonded ceramics (FBC) was investigated. Stress-strain curve of the FBC was linear up to 120 MPa, and showed nonlinear behavior in the higher stress level. Micro-fracture in 90° layers, such as delamination at the fiber/ matrix interface, was observed by the SEM. It was shown that evolution of the micro-fracture was closely related to the degradation in Young's modulus.

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The thermal shock damage mechanism in unidirectionally reinforced Si-Ti-C-O fiber bonded ceramics (FBC) was experimentally examined using a water quench technique. Two types of damage were introduced in the FBC specimens. One was macroscopic crack along the fiber direction introduced at the temperature differene (ΔT) of 600K and above. The other was microscopic damage near the surface of the specimens, which was delamination at the fiber/matrix interface. Finite element analyses were carried out to obtain the maximum stress during the thermal shock tests. Even below the critical temperature, the maximum stress exceeded the transverse tensile strength of the FBC. To clarify the criterion for the initiation of the macroscopic crack, the energy release rate (G) was examined by the FEM. This result suggested that the macroscopic crack was introduced following the fracture mechanics criterion. The stress relaxation mechanism and evolution of the damage area were also examined by changing the materials properties of the damaged area.

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Tensile failure mechanisms of C/C composites, were attempted to be clarified. Three regions as a function of C/C density have been identified to be governed by different, mechanisms. For low density ρ < 1.5, C/Cs tensile elongation was shown to be ruled by inhomogeneous load transfer, for the medium range, 1.5 < ρ < 1.7, by Young's modulus, and for the high density range, ρ > 1.7, by the interfacial bonding strength between fiber and matrix.

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Interfacial strength between the matrix and individual fibers in a Carbon/Carbon (C/C) composite is attempted to be measured by Vickers indentation method. Three kinds of the method, push-in and micro- and macro-push-out tests are proposed to evaluate the interfacial strength of C/C composites. It is shown that the micro-push-in test yielded most plausible the interfacial strength for C/C composites.

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The tensile and compressive stress-strain responses and cyclic stress-strain response were investigated for sintered silicon nitride ceramics at elevated temperatures, using the ultra-high temperature-use- extensometer which was developed in the authors' laboratory. The large inelastic strain, which is greatly dependent on stress rate, was produced under tensile, compressive and cyclic push-pull triangular wave loadings in this material at 1300℃. Furthermore, inelastic strain decreases with increase in the number of loading cycles at 1300℃, showing increase in resistance to deformation in cyclic loading process. It was found from these tests that inelastic strain is easier to generate under tensile loading than under compressive loading.

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Compressive behavior of 2D and 3D Carbon/Carbon (C/C) composite was investigated. 2DC/C showed relatively linear deformation up to the total fracture. However, 3DC/C showed large nonlinear deformation accompanying the load drop and recovery and no clear fracture was observed. In 2D specimen, the progressive microcracking was not observed during the testing, however, interlaminar delamination was observed. In 3D specimen, the microcracks didn't appear until the first stress peak of the δ-U curve, and after the peak, the delamination between X-Y bundle and shear failure of the Y bundle near the matrix pocket was observed. From the experimental observation, the initiation of the progressive fracture of 3DC/C was supposed as the interlamina delamination, which ruled the fracture of 2DC/C. However, the existence of Z directional fiber prevented the specimen from catastrophic failure. The fracture strength of both the C/Cs was discussed using micro-kinking model by Rosen and shear fracture model by Ewins & Ham.

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Ceramic Injection Molding(CIM) is suitable for manufacturing complex shape products. However, considerable distortion occurs in de-waxing stage. It is caused by the visco-elastic deformation, due to the release of the latent strain, which is generated in the material during injection molding stage. In this paper, injection molding into T-shaped cavity has been dealt with and distortion in de-waxing stage is examined. Then, the distortion property is discussed in consideration with visco-elastic property of material.

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In situ observation of the mechanical failure behavior was conducted of different kinds of the plasma sprayed thermal barrier coating (TBC) systems by means of an optical microscopy under the static loadings at ambient temperature; as the most fundamental aspect, in order to clarify the failure mechanism of TBCs. Several kinds of TBC systems were prepared by using different coating parameters such as top-coat powder, thermal spraying process, heat treatment conditions and so forth. Mechanical tensile or compressive loadings were applied progressively to the TBC specimen by the four-point bending test methodology. The influence of TBC microstructure on the crack initiation and propagation behavior was investigated in detail. Furthermore, the TBC failure was quantitatively evaluated in relation with the mechanical strain applied on the top-coat surface.

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Creep fracture characteristics consist of the initiation and growth behavior of creep voids , creep fracture mode, and rupture life. However, initiation and growth behavior of creep voids in multi-axial stress states have not been made clear. In this study, using ductile austenitic steel SUS310S. tensile creep, torsional creep and tensile-torsional creep tests with tubular specimens are conducted at 700℃. Creep voids in test-stopped specimens are examined in detail by observation on the scanning electron micrographs. The initiation and growth behaviors of creep voids under multi-axial stress conditions are discussed.

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The tensile tests of the bare(non-coated) and SiC-coated C/C composites were carried out in air at elevated temperatures (RT-1600℃). Specimens were exposed in air at a testing temperature for 600s under a constant strain, 0.13%, and then loaded to the failure in N_2. Experimental results showed that the oxidative damage of the SiC-coated substrate at 1200℃ was induced only just below the coating cracks causing a groove with a semi-circular cross-section. This indicates that the residual strength SiC-coated substrate can be predicted from the apparent remaining cross-section. The increase in the oxidative groove radius was also predicted using the decrease in the applied load during the exposure. The predicted oxidative groove radius showed good agreement with the measured value.

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A new simulation model of recrystallization processes is proposed in this report. The model is based on nucleation and grain growth theory, and is combined with the deformation enegy thoery, which estimates the effect of plastic deformaiton on metallurgical phenomena by the generalized deformation energy. In this model, dispersion of grian growth rate is also taken into account, and a new differential equation that expresses grain size variation is proposed. The model was verified by numerical simulation. The calculated grain size variation showed qualitically proper characteristics as static recrystallization process. The model was also adopted to ABAQUS, and a forging and annealing process was simulated by the FE analysis.

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New analytical model for the evolution of texture of BCC lattice in cold forming is proposed. Transition probability function is introduced to choose activative slip system of BCC lattice, which has three slip-phase systems, {110} <111>, {112} <111>, {123}<111>. Numerical results obtained by this model agree well with the experimental measurement, when the transition probability to activate {110} <111> systems is 70%.

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Hot extrusion systems of steels with controlled cooling has been developed. This system aims to control microstructure of steels flexibly, using heavy plastic deformation and direct heat treatment. Microstructure of extruded products obtained by experiment with different cooling curve after hot extrusion is shown, and characteristic of developed system is discussed.

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Change in austenite grain size after continuous bar rolling of S45C steel with 3-roll mill is investigated. From the double hot compression test with large plastic strain, when dynamic recrystallization takes place, it becomes clear that final austenite grain size is dominated only by the final deformation, even if inter-pass time is quite short. This proves that the size of final austenite grains, such as coarsened grains,,is affected not by the amount of plastic deformation but by the final forming condition, when the dynamic recrystllization takes place. This is confirmed by experimental results obtained by continuous rolling with 7-stands.

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In order to develop the high strength materials, the forming process with large strain is one of available processes. The authors have developed the repeated shear deformation process with side pressure under high hydrostatic pressure. In this study, the aluminum base materials (pure aluminum and Al-Mg alloy) are deformed by shear deformation process with side pressure, and TEM observation for microstructure of those materials was carried out. By 10 times repeated shear deformation process, grain size of those materials became smaller and misorientation angle became higher. After 10 times deformation, fine grain structures with high angle boundary were obtained. The grain size was long length of 1.2μm and short length of 0.2μm in pure aluminum, and long length of 0.8μm and short length of 0.1μm in Al-Mg alloy.

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It is supposed that the effect of shear strain layer of the drawn wire surface is one of the causes of "size effect". The relations between tensile strength and wire diameter were investigated by examining the depth of shear strain layer. As the result, it is concluded that: (1) on drawing process, no matter wire size, the depth of shear strain layer is almost the same in every process. Therefore larger area of fine wire section is occupied by these shear strain layer. (2) the shear strain layer is not piled up in each process. (3) the shear strain layer remarkably effects on tensile strength of fine wire.

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Intelligent actuators, which can control their own stroke have contributed to robot system and factory automation. Usually, stroke is detected by using a sensor located on one end of the actuator and its construction is very complex. The space and the condition for using it are restricted because of the location of the sensor. To solve this problem, a new kind of actuator was developed. This actuator's piston rod has magnetic scales made by irradiating with laser beam. The scaling rod is stronger and more accurate. However, irradiating with laser is expensive and the working time is very long. Therefore, a new manufacturing process with plastic work is developed to improve productivity.

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It is well known that the deformation of the Fe-18 Cr-8 Ni system (SUS304 stainless steel) induces the formation of the martensitic α phase within its parent austenitic γ phase. This martensitic transformation is accompanied by a paramagnetic (γ phase) to ferromagnetic (α phase) transition. This phenomenon has been used to produce a magnetic functionally graded material using an inhomogeneous tensile deformation of a 304 stainless steel. However, detailed knowledge of inhomogeneous deformation behavior is necessary to predict the magnetically graded structure within the specimen. In this study, inhomogeneous deformation behavior of wedge-shaped tensile specimens is studied for SUS304 and SUS310 stainless steels, pure aluminum and pure copper.

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Steady state creep doesn't exist and the minimum strain rate exists for A5083 at a constant stress. The initial creep of A5083 differs from that of pure aluminum. The inverse transient creep is observed for A5083. We obtain the experiment equation, t^* = t^0σ^δexp(Q^*/RT), for the incubation time.

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Fracture control design is able to predict and to manage fracture by means of estimation of damage. It requires fatigue crack propagation behavior of structural materials. I investigated the effect of the environment and of the frequency on the fatigue crack propagation behavior of 5083-O and 7075-T651 aluminum alloys. Moisture accelerated crack growth among any other environment. Gas element has no effect on the crack growth either under a dry or a wet condition. The crack growth in the higher ΔK region was faster at a lower frequency under a dry condition. While the parameter "C" in Paris Law was related with environmental and mechanical factors, the parameter "m" was rather related with materials itself.

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It is known that the electric charge between copper electrodes in distilled water results in precipitation of copper dendrite structure. Using this phenomenon, formation of copper dendrite with leaning effect was examined. When DC voltage was applied to copper electrodes that were immersed in water, electic resistance was apparently charged. Observation by optical microscope showed that dendrite structure grew to specific direction. Furthermore, pattern of electric charge was varied and the possibility of leaning of electric charge pattern was investigated.

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The primary aim of present study is to clarify the fatigue fracture mechanism of high strength steel at the high cycle region. Oil-tempered high strength steel wire (SWOSC-V) is prepared for fatigue test by using Nakamura rotating-bending fatigue testing machine. The S-N diagram had a knee point at about 10^5cycle. From scanning electron microscopy (SEM) observation of the fracture surface at the long cycle fatigue range, nonmetallic inclusion was identified at the origin of fracture and it formed "fish-eye" failure. On the other hand, a constitution of the nonmetallic inclusion is measured by using electron probe micro analyzer (EPMA). As a result, Aluminum, calcium and oxygen were detected mainly at the inclusion. Based on these results, finite element analysis (FEA) was conducted for analyzing the stress field around the neighborhood of the nonmetallic inclusion. Then, the effect of mechanical property of inclusion on fatigue failure behavior was discussed.

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A transition phenomenon in flattening of thermal sprayed particles on a flat substrate surface has been investigated. Our previous results showed that as a substrate temperature increases, a splat morphology changes from irregular splash shape to disk shape transitionally at a certain substrate temperature range. In this study, Splashing parameter defined as K=We^<0.5> Re^<0.25> for a breakup phenomenon of a liquid film, was introduced as a judgment factor for splashing in flattening of thermal sprayed particles. Consequently, it was found that only Splashing parameter could not judge the transition behavior in a flattening of particles with solidification such as a thermal sprayed particle. Therefore, new judgment factor for the transition phenomenon in flattening of thermal sprayed particles was proposed.

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Newly developed bonding process, which was performed by heating the metal using high-frequency induction furnace then melt the salt consisted of borax, carborundum and silicon carbide, was applied to several kinds of steels in order to find its feature. The study was carried out on the effect of chemical composition in steels and salts on the properties of boride layer. Thick layer was obtained by using the salt containing carborundum. Increasing chromium content of the steels inhibited bonding and consequently needle-like boride layer changed into smooth one. Boride layer made by induction heating grew more thick than the one by conventional immersion method.

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In this work, feasibility study has been conducted to produce NiTi intermetallic compound coatings using both composite powder of NiTi (alloyed powder) and physically mixed powder of Ni and Ti by plasma transferred arc welding process. Wear characteristics of the coatings were evaluated by a modified Okoshi-type wear tester. Based on the obtained results, it was possible to produce intermetallic compound coatings on carbon steel from the simply mixed powder as well as composite powder by plasma transferred arc welding process. Hardness value reached up to 800HV in the NiTi coatings, and then the resistance to sliding wear was much improved in comparison with that of Stellite#6 coatings.

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Application of the unloading method to measure the elastic-plastic fracture toughness JIC of ductile iron was studied and the following results were obtained; the inclination of the load versus load line displacement curve at the initial loading period becomes somewhat smaller than those of the unloading lines of the early unloading times and it results in negative values in calculation on crack growth, however an appropriate R-curve can be obtained by shifting the entire curve following to the behavior of the crack growth calculated from each unloading compliance.

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Mechanical properties and structure of Fe-Si added spheroidal graphite cast steels were investigated. No graphite was observed less than 2% Si content in the case of 1.15% C content. Spheroidal graphite decreased and compacted vermicular graphite increased by the increase of Si content in the case of 1.50% C content. Tensile strength was lowered value by the increase of C content in constant value of Si content. Tensile strength was lowered value by increase of Si content in constant value of C content.

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In order to heat the billet uniformly and to prevent mushy-state materials from cooling by dies, a mushy-state forming method using electric resistance heating is proposed. A laminated plate made of graphite and stainless steel sheets is developed as a heat source. The dies function as electrodes to introduce electric current into the billet. In the experiments with steel dies and an aluminium alloy, the billet heated by electricity without the laminated plate exhibits solid zones contacting the dies. By heating the billet with the laminated plate, the whole billet becomes semi-solid. By using this method, compression test are carried out at the mushy-state temperatures and flow stresses are measured. The electric resistance heating with the laminated plate is applied to thixoforging.

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This paper reports the development of car component by Thixo Casting Tecnology. Automobile weight reduction by the aluminum hybrid body construction was carried out for low fuel consumption of the automobile.This construction needs some joint parts. The Thixo Casting Tecnology was used for one of this joint parts. Did in-house production of the billet which was raw stock in order to mass-produce it by the Thixo Casting Tecnology. Show effect of this development with comparison of the Thixo Casting Tecnology and LPDC manufacturing method. As for the Thixo Casting Tecnology, wall thickness decreased by 22% compared with the LPDC manufacturing method.As for the weight, 20% decreased.Furthermore, as for the intensity, 20% improved.

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We have developed new Semi-Liquid Metal Casting process. The characteristics of this process are as follows. (1) The alloy slurry is formed during cooling from molten state in shot sleeve (Billet less process) (2) The castings show good mechanical properties (high strength and high elongation) (3) Low Oxide film contamination due to planar flow molten metal supply to shot sleeve by electromagnetic pump poring system. (4) The parts we applied are Front Lower Link and Rear Upper Arm for Middle-class automotive (3.0L). In this paper, the outline of the process and several characteristics of the castings are presented. Compared with some other casting methods The castings which made by this process are able to apply T6 heat treatment(the range of solution treatment temperature is 530〜540℃). And they also show good weldability.

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