• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.10a
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• pp.102-109
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• 1997

The surface deformation of shadow mask was studied by the experiments and numerical analysis for process improvement and delet of the stabilizing process in the shadow mask manufaturing line. To inverigate the thermal deformation of shadow mask with and without stabilizing process mask, data of spring strength, frame flatness, frame magnetic force and a mask surface curvature were measured. The tube characteristics of two kind of shadow masks were also investigated.

• Transactions of Materials Processing
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• v.5 no.4
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• pp.297-304
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• 1996

A process model is formulated considering the effect of crystallographic texture developed in forming process. The deformation induced plastic anisotropy can be predicted by capturing the evolution of texture during large deformation in the polycrystalline aggregate. The anisotropic stiffness matrix for the aggregate is derived and implemented in Eulerian finite element code using a Consistent Penalty method. As an application the evolution of texture in rolling drawing and extrusion processes are simulated. The numerical results show good agreements with report-ed experimental textures.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.03a
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• pp.183-191
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• 1994

This paper suggests the scheme to simultaneously accomplish prediction of fracture initiation and analysis of deformation in metal forming processes. the Cockcroft-Latham criterion is used to estimate whether fracture occurs during the deformation process. The numerical predictions and experimental results of simple upsetting are compared. The proposed scheme successfully predicted the fracture initiation found experimentally.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.87-90
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• 2007

The evolution of texture and microstructure was tracked for a number of differently cold rolled aluminum sheet and through-thickness layers which were differentiated by different strain states upon preceding deformation. The results substantiate a correlation of deformation texture with the amount of shear applied during cold rolling.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.123-126
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• 2007

Deformation behavior of $Zr_{55}Cu_{30}Al_{10}Ni_5$ (at. %) bulk metallic glass (BMG) fabricated by suction casting method has been investigated at elevated temperatures in this study. The BMG was first verified to have an amorphous structure thru X-ray diffraction (XRD) and differential scanning calorimetry (DSC). A series of compression tests has consequently been performed in supercooled liquid temperature region to investigate the high temperature deformation behavior. A transition from Newtonian to non-Newtonian flow appeared to take place depending upon both the strain rate and test temperature. A processing map based on a dynamic materials model has been constructed to estimate a feasible forming condition for this BMG alloy.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.362-365
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• 2009

Microstructural evolution and the mechanical properties of various carbon steels were investigated with the variation deformation temperature to explore the optimum microstructure with excellent combination of strength and ductility. For this purpose, three carbon steels containing different carbon contents were deformed using Gleeble 3500 at temperatures including austenitic, austenitic/ferritic, austenitic/cementitic, ferritic/cementitic regions. The results showed that in the medium and high carbon steels, cementite particles became finer with decreasing deformation temperature resulting higher hardness but lower ductility. Further effort is needed to find out optimum microstructures with enhanced mechanical properties.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.10a
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• pp.244-247
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• 2001

Lubricanting characteristics in the warm forging have influence on forgeability of products. but Research on deformation characteristic of warm forging on the lubricant and lubricating method lack. This paper deform a bevel gear by warm forging and evaluate deformation loads and quality of products by each lubricants and lubricating method using oil-based lubricants(Soy, Oildag) and water-based lubricants(Deltaforge $\#31$, Renite S-26-X, Deltaglaze $\#151$). In conclusion, the less a deformation load by lubricants the more improvement a quality of product in manufacture of a bevel gear and water-based lubricants in the warm forging reduce a deformation load and improve a quality of products. Especially, Deltaforge $\31$ have excellent characteristic in the warm forging.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.10a
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• pp.264-267
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• 2001

by three-dimensional finite element method. The guide roll is an intermediately supported trans-axle miler, so called I-STAR roll, which was designed by VAI. The guide roll has been used in POSCO since 1998. Though the number of stowage in casting has been apparently decreased since thef it has occasionally been failed during operation. The simulations were carried out to find out the status of stress and deformation as well as improvement of the guide roll. The thermal effect is much more dominant than ferro-static pressure or others in stress and deformation of the guide roll. The material of the guide roll is SCM440.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.176-178
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• 2003

Strip samples of AA 3103 were deformed by Continuous confined strip shearing (CCSS). The CCSS process was designed to provide a repeated shear deformation in metallic sheet materials. CCSS led to the formation of characteristic shear textures comprising a pronounced｛111｝＜uvw＞ orientations. The intensity of the deformation texture hardly increased with increasing number of CCSS passes. EBSD equipped in a FESEM with a high beam current revealed the formation of fine grains even after annealing for the recrystallization.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.363-366
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• 2003

In nanomachining processes, chemical effects are more dominant factor compared with physical deformation. For example, during the nanoscratch on a silicon surface in the atmosphere, micro protuberances are formed due to the mechanochemical reaction between the diamond tip and the surface. On the contrary, in case of chemically stable materials, such as ceramics or glasse, the surface protuberance are not formed. The purpose of this study is to understand effects of the mechanochemical reaction between tip and surfaces on deformation behaviors of hard-brittle materials. Nanometerscale elasoplastic deformation behavior of single crystal silicon (100) was characterized with the surface protuberance phenomena, and compared with that of borosilicate (Pyrex glass 7740).