• Transactions of Materials Processing
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• v.10 no.3
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• pp.253-260
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• 2001

This study was performed to investigate the optimized warm forming conditions which gave the maximum drawing depth in square cup drawing of clad sheet metals, by changing the temperatures of die and blankholder and also shapes and materials of blanks. Two kinds of clad sheet metals, STS304-A1050-STS304 and STS304-A1050-STS430 were selected for experiments. The relative drawing depth of STS304-A1050-STS304 clad sheet was increased up to 4.4 at $150^{\circ}C$ that was 29% higher than at room temperature, whereas STS304-A1050-STS430 material was improved to 3.9 at $120^{\circ}C$ which was 15% better than at room temperature. In addition, comparison of wall thickness and hardness of a warm drawn cup with those of room temperature showed more even distributions. No separation between each laminated material after drawing occurred through inspection by microscope as well as application of penetrant test and bond strength test. Therefore, warm forming technique was confirmed to give better results in deep drawing of stainless clad sheet metal.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.02a
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• pp.136-143
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• 2002

Warm draw die technique which is one of the new forming technologies to improve formability of sheet metal is applied to the cylindrical and square cup drawing of stainless-aluminum clad sheets. In experiments the temperature of die and blank holder is varied from room temperature to $180^{\circ}C$, while the punch is cooled by circulation of coolant to increase the fracture strength of workpiece on the punch comer area. Test materials chosen for experiments are STS304-A1050-STS304 clad sheets. Teflon film as a lubricant is used on both sides of a workpiece. The limit drawing ratio and relative drawing depth as well as quality of drawn cups(distribution of thickness)are investigated and validity of warm drawing process is also discussed. No separation between each laminated material after drawing occurred through inspection by microscope as well as application of penetrant remover and bond strength test. Therefore, warm forming technique was confirmed to give better results in deep drawing of stainless clad sheet metal.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.3
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• pp.67-72
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• 2015

A study on thermal properties for a single-layer metal and a 2-ply metal (clad metals) was investigated for the application of heat sink. For the single-layer metal, a stainless steel (STS) and an aluminum (Al) were selected. Also, a roll bonded clad metal with STS and Al was chosen for the 2-ply metal. The thermal conductivity of the sample was obtained from the thermal diffusivity measured by the light flash analysis (LFA), specific heat and density. Measured thermal property values were compared with the calculated values using the data from the references. For the single-layer metal, measured values for the thermal diffusivity and thermal conductivity were smaller than calculated values. Differences between measured and calculated values were about 6% and 18% for the STS and Al samples, respectively. For the clad metals, however, a large difference (55%) was observed. Here, a relatively small thermal conductivity measured by LFA was due to the existence of a interface between STS and Al in the clad metal. Such a interface reduces the moving velocity of free electrons and phonons in the clad metal. For the development of a high performance heat-issipation module with the multi-layer structure, the control of interface properties which determine thermal properties was confirmed to be important.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.121-122
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• 2009

• Korean Journal of Metals and Materials
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• v.50 no.12
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• pp.939-948
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• 2012

A 3-ply clad metal consisting of aluminum and copper was fabricated by roll bonding process and the microstructures and mechanical properties of the roll-bonded and post-roll-bonding heat treated Cu/Al/Cu clad metal were investigated. A brittle interfacial reaction layer formed at the Cu/Al interfaces at and above $400^{\circ}C$. The thickness of the reaction layer increased from $12{\mu}m$ at $400^{\circ}C$ to $28{\mu}m$ at $500^{\circ}C$. The stress-strain curves demonstrated that the strength decreased and the ductility increased with heat treatment up to $400^{\circ}C$. The clad metal heat treated at $300^{\circ}C$ with no indication of a reaction layer exhibited an excellent combination of the strength and ductility and no delamination of layers up to final fracture in the tensile testing. Above $400^{\circ}C$, the ductility decreased rasxpidly with little change of strength, reflecting the brittle nature of the intermetallic interlayers. In Cu/Al/Cu clad heat treated above $400^{\circ}C$, periodic parallel cracks perpendicular to the stress axis were observed at the interfacial reaction layer. In-situ optical microscopic observation revealed that cracks were formed in the Cu layer due to the strain concentration in the vicinity of horizontal cracks in the intermetallic layer, promoting the premature fracture of Cu layer. Vertical cracks parallel to the stress axis were also formed at 15% strain at $500^{\circ}C$, leading to the delamination of the Cu and Al layers.

• Korean Journal of Optics and Photonics
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• v.13 no.2
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• pp.134-139
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• 2002

We report an experimental investigation of the wavelength and polarization selectivity of a side-polished fiber in contact with a metal-clad planar waveguide. The influences of the structural parameters of the planar waveguide, including refractive index of the superstrate and metal thickness, on the optical transmission characteristics of the device were measured and explained. The conditions for high wavelength and polarization selectivity wore predicted and demonstrated experimentally.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.264-267
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• 2006

This paper describes the accident analysis by modeling the current transformer mounting in meaium voltage metal-clad switchgear(MCSG). In analyzing the accident the reconstruction at the current transformer mounting(VCB connecting guide) has to be taken into account. The accident was modelled as a 3-phase ground fault mounting between the end plate of a high voltage lines and the safety shutter at the current transformer mounting of the VCB inside the metal clad switchgear. Since the outside maintenance of the metal clad switchgear is restricted by the enclosed compartments, its circumference has to be kept clean. Through the reconstruction results, it was confirmed that the fault of the enclosed switchboard could be reduced when the shutter made of Fe material was changed into an insulation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.89-93
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• 2001

This study was carried out to investigate the warm deep drawability of square cups of clad sheet metals, by changing temperatures of die and blankholder and blank materials. Two kinds of clad sheet metals, STS304-A1050-STS304 and STS304-A1050-STS430 were chosen for experiments. The relative drawing depth of STS304-A1050-STS304 clad sheet was increased up to 4.4 at $150^{\circ}C$ that was $29\%$ higher than at room temperature, whereas STS304-A1050-STS430 material was improved to 3.65 at $120^{\circ}C$ which was $16\%$ better than at room temperature. In addition, comparison of wall thickness and hardness of a warm drawn cup with those of room temperature showed more even distributions. Therefore, warm forming technique was confirmed to ive better results in deep drawing of stainless clad sheet metal.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.3
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• pp.13-19
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• 2005

Metal Bearing's research that use the clad steel had led in advanced country. Metal Bearing that is produced by domestic companies is ship, vehicles, development equipment and plant equipment. This is Cast White Metal Lining Bearing that is Bimetal Bearing standing 2 generation. Cast White Metal Lining Bearing is foreseen to be used widely on industry whole in the future. Cast White Metal Bearing is product that need precision processing. But the technique is generalized widely. So an advanced country is depending on import from a developing country that price is cheaper than itself manufacture. it is judged that high added value creation by deepening of price competition is difficult. Therefore need product development of new form and is changing to Trimetal Bearing parts. Trimetal Bearing is high quality technique that do compression junction to thin plates of special object on the Back Metal. Therefore, this research developed Trimetal bearing's materials.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.1 s.173
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• pp.87-93
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• 2000

Warm, forming technique which is one of the new forming technologies to improve formability of sheet metal is applied to the cylindrical cup drawing of stainless-aluminum. clad sheets. In experiments the temperature of die and blank holder is varied from room temperature to 18$0^{\circ}C$, while the punch is cooled by circulation of coolant to increase the fracture strength of workpiece on the punch corner area. Test materials chosen for experiments are STS304-A1050-STS304, STS304-A1050-STS430 clad sheets and A1050-0 aluminum sheet. Teflon film as a lubricant is used on both sides of a workpiece. The limit drawing ratio as well as quality of drawn cups(distribution of thickness and hardness)are investigated and validity of warm drawing process is also discussed.