• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.283-286
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• 2005

Because CV Joint which is one of the component of automobile power train system communicates high power and performs power steering function, it requires high qualities such as high strength, high toughness and high fatigue resistance. This component undergoes a series of production processes such as forging, machining and heat treatment and required properties for this component depends on plastic deformation and heat treatment heavily. Therefore in this study, in order to these effects on mechanical properties due to plastic deformation and heat treatment we performed heat treatment following plastic deformation and then tensile test.

• Journal of Welding and Joining
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• v.19 no.4
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• pp.384-390
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• 2001

There have been many problems due to deformation in industry field. Especially, it is severe in parts with small size and thin thickness and in products that must have excellent airtightness and anti-noise. The countermeasures for this deformation in field have mainly been dependent on the rule of trial and error by operator's experience because of productivities. Systematic study about this product with deformation is also insufficient that deformation is complex problem with shape, size, material of product, joining method and conditions, etc.. It is efficient to apply CAE technique without influence on productivity to this problem. There is, however much difference between the result analyzed by CAE and appearances in working field because of the insufficiency of communication between simulator and worker and of sensing data for boundary condition in analysis. In this study, to solve this deformation problem, we intend to make a simulation model that is adapted from working conditions by tuning and feedback between sensing data and simulation results. This paper include temperature monitoring and make a heat transfer model using sensing data in product as previous step for deformation analysis. The heat transfer analysis of shrinkage fit process is considerably difficult due to contact heat transfer between case and core. To solve this contact problem, gap element is used in present study.

• Journal of Welding and Joining
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• v.31 no.6
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• pp.44-49
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• 2013

The influence of thermo-mechanical cycling on the microstructure and strength in the weld coarse-grained heat affected zone (CGHAZ) of Ti-Nb added low carbon HSLA steel was explored through Vickers hardness tests, nanoindentation experiments, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. Undeformed and deformed CGHAZs were simulated using Gleeble simulator with different heat inputs of 30kJ/cm and 300kJ/cm. At high heat input of 300kJ/cm, the CGHAZ consisted of ferrite and pearlite and then their grain sizes were not affected by deformation. At low heat input of 30kJ/cm, the CGHAZ consisted of lath martensite and then the sizes of prior austenite grain, packet and lath width decreased with deformation. In addition, the fraction of particle increased with deformation and this is because the precipitation kinetics was accelerated by deformation. Meanwhile, the Vickers and nanoindentation hardness of deformed CGHAZ with 30kJ/cm heat input were higher than those of undeformed CGHAZ, which are due to the effect of grain refinement and precipitation strengthening.

• Journal of Welding and Joining
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• v.20 no.4
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• pp.544-550
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• 2002

Arc-spot welding is generally used in joining of precise parts such as case and core in electronic compressor. It is important to control joining deformation in electronic compressor because clearance control in micrometer order is needed for excellent airtightness and anti-nose. The countermeasures far this deformation in field have mainly been dependent on the rule of try and error by operator's experience because of productivities. For control this deformation problem without influence on productivities, development of exact simulation model should be needed. In this study, to solve this deformation problem in arc-spot welded structure with case and core, we intend to make a simulation model that is able to predict deformation in precise order by tuning and feedback between sensing data and simulation results. This paper include development of heat input model for arc-spot welding, temperature monitoring and make a heat transfer model using sensing data in product.

• Journal of the Korean Society for Heat Treatment
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• v.17 no.4
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• pp.211-215
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• 2004

Conventional spheroidization process of cold heading quality steels requires long heat treatment time, and reduction of the heat treatment time is important for improving productivity in the industry. Recently, hot deformation method has been proposed as a means of increasing spherodization kinetics. In this study, the influences of hot deformation on the spherodization behavior of cold heading quality steels were investigated. Hot deformation at the temperature range of $700^{\circ}C$ significantly enhances the spheroidization kinetics. Hot deformation can lead to a substantial reduction of spherodization process time as low as 1~5 hrs.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.03a
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• pp.47-54
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• 1994

The study is concerned with the coupled analysis of heat transfer and thermoelastoplastic deformation. The thermoelastoplastic model is very useful for the analysis of residual stress and the analysis of thermal stress as well as the analysis of metal forming. Heat of deformation, phase transformation and contact heat transfer boundary are considered. The contact heat transfer boundary is treated by the interpolation of shape function. The analysis of deformation and the analysis of heat transfer are carried out for the could upsetting and the hot rolling. The computed results are found to be in good agreement with the experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.5
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• pp.44-52
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• 1996

A procedure predicting warpage and post-deformation due to heat resistance test is presented. The procedure is applied to the injection molding processes of automotive plastic components, which are the door trim and the instrument pannel. The warpage of products is obtained from the residual stress after filling, packing and cooling process, and the post deformation due to the heat resistance test is calculated in the structural analysis of the product at the ejection temperature with the initial condition of residual stress, the boundary conditions and heat resistance conditions. The analyses give some useful guide lines in the design of automotive plastic parts which should satisfy heat resistance regulation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.260-263
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• 2004

Since Outerrace is one of the components of driving shaft for power train of automobile and transmits high torque, high strength and high toughness are necessary so forging process is adopted to manufacture such parts. Therefore, in order to improve strength and toughness, heat treatment is accomplished after plastic deformation(forging). Because Each component of driving shaft is mounted to automobile after a series of forging, machining and heat treatment, in order to evaluate mechanical properties of such components in use, plastic deformation and heat treatment must be considered. So, in this paper, tensile tests are performed with tensile specimens which have passed through a series of upsetting, machining and heat treatment to evaluate mechanical properties of such components.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.395-398
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• 1997

In the modem manufacturing system, to achieve the unmanned automation, the stability of accuracy is required through a long working period. The thermal deformation of precision machine is predominant in this long time stability. While grinding slender and long workpiece at cylindrical grinding machine, we support workpiece using steadies to prevent the vibration of workpiece. The thermal deformation of the machine by grinding and internal heat source cause processing errors, so the steadies for compensating the thermal deformation in real time are strongly needed. In order to compensate these thermal deformation and grinding processing errors, the device to determine the precise positioning having the stroke of 10.mu.m is necessary. This paper suggests design and make the device to determine the precise positioning using thermoelectric device, to investigate the control characteristics and presents the heat actuator will be very useful in machine tool.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.05a
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• pp.39-43
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• 2002

A new model for heat transfer and thermal deformation analysis according to strip mm in coiling process has been proposed. Finite difference analyses for heat transfer of cold rolled coil have been carried out under various coiling tensions and strip crown using the equivalent thermal conductivity for the radial direction of cold rolled coil which is a function of strip thickness, surface characteristics and compressive pressure. The compressive pressure is calculated from a equation expressed as a function of hoop stress and coil tension considering strip mm obtained by experiment. Finite element method for thermal deformation of cold rolled coil has been performed to investigate the effects of the strip crown, the coil tension and temperature. From these analyses, it is found that the axial inhomogeneity of thermal deformation is increased as the strip crown, compressive pressure, and temperature drop in cold coiled strip increase.