• Journal of the Korean institute of surface engineering
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• v.46 no.5
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• pp.192-196
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• 2013

Stainless steels (AISI 316L) are carburized by Inductively coupled plasma using $CH_4$ and Ar gas. The ${\gamma}_c$ phase(S-phase) is formed on the surface of stainless steel after carburizing process. The XRD peak of carburized samples is shifted to lower diffracting angle due to lattice expansion. Overall, the thickness of ${\gamma}_c$ phase showed a linear dependence with respect to increasing temperature due to the faster rate of diffusion of carbon. However, at temperatures above 500, the thickness data deviated from the linear trend. It is expected that the deviation was caused from atomic diffusion as well as other reactions that occurred at high temperatures. The interfacial contact resistance (ICR) and corrosion resistance are measured in a simulated proton exchange membrane fuel cell (PEMFC) environment. The ICR value of the carburized samples decreased from 130 $m{\Omega}cm^2$ (AISI 316L) to about 20 $m{\Omega}cm^2$. The sample carburized at 200 showed the best corrosion current density (6 ${\mu}Acm^{-2}$).

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.1
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• pp.1-7
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• 2006

A method of the volumetric error measurement and calibration of NC machine tools is studied using an artifact method. In this study, a hole-pate is designed and machined using stainless steel. We tested and applied the hole-plate artifact in a commercial CMM(Coordinate Measuring Machine), after calibration of the hole-plate using a precise CMM. It has been shown that not only the measurement of geometric error components but also the 2D length error calculation in a working volume is available using the hole-pate artifact method. The results of study can also be used in NC machine with touch probe as the same method in CMM.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.229-232
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• 2005

This paper presents the design and fabrication of backflow prevented Micropump using the metal membrane. The Micropump is consisted of the lower plate, metal membrane, upper plate and the piezoelectric-element. The lower plate includes the micro channel and the inlet, outlet of the Micropump. The upper plate includes the micro channel and connects the piezoelectric-element. These plate are fabricated on the Pyrex glass wafer by sandblasting process. The metal membrane does roll of check valve that is prevented backflow of the Micropump. The metal membrane is fabricated on the stainless steel by laser machining. Piezoelectric-element is actuated the Micropump and controlled flowing of fluid. The Micropump is fabricated by bonding process of these multi-layer.

• Journal of Welding and Joining
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• v.31 no.2
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• pp.49-56
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• 2013

We have investigated traits of clad metals in hot-rolled clad steel plates, sensitization and mechanical properties of STS 316 steel plate and carbon steel(A516). Clad steel plates were butt-weld by SAW+SMAW, and with the time of heat treatment as the variable, heat treatment was conducted at $625^{\circ}C$, for 80, 160, 320, 640, 1280 minutes. As a way to evaluate it, sectioned weldments and external surfaces were investigated to reveal the degree of sensitization by mechanical property, etching and those of EPR test, results were compared with it. In short, the purpose of this study is suggesting some considerations in developing on-site techniques to evaluate the sensitization of stainless steels.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.7
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• pp.112-117
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• 2003

The brazing of copper alloys and duplex stainless steels is an indispensable manufacturing technology for thrust chambers with regenerative cooling. For setting up the optimized brazing conditions, C18200 copper alloy plate with machined cooling channels and S31803 stainless steel plate are brazed with AMS4764 filler metals of which thickness is 50${\mu}m$ and 80${\mu}m$ They are tested by X-ray radiography, strength/leakage and fracture tests, and fracture surface inspection. The results obtained by the suggested conditions are that the specimen brazed with filler metal thickness of 50${\mu}m$ has good strength properties and brazed zone. However, the specimen with filler metal thickness of 80${\mu}m$ has the brazed zone with cooling channel obstruction and enlargement.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.207-212
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• 2004

Full-beads of multi-layer steel engine head gaskets that are used to seal the combustion gas between the head and the block are subject to cyclic bending stresses due to the variation of the head/block gap during engine operation. The S-N curve for the fatigue durability assessment of the full-bead formed on NBR-coated SUS301 thin plate is deduced from the axial fatigue test results because of the difficulty in conducting the bending fatigue test of thin plate. The experimental verification of the deduced S-N curve is presented. It is shown that the NBR coating increases the endurance limit of the plate significantly. Mechanism of crack nucleation and propagation in the full-bead is discussed with photographs of the fatigue cracks.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.516-521
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• 2000

Most of studies, using ESPI method, have handled tension, thermal and vibration analysis, and is limited to isotropic materials. However, tension and vibration simultaneously are loaded in real structure. Also, almost study using ESPI method is locally limited to the analysis on the isotropic materials and a few studies on the anisotropic materials have reported. Existing methods, such as the accelerometer method and FEA method, to analyze vibration have some disadvantages. Using the accelerometer method that is generally used to analyze vibration phenomena, it is impossible to analyze vibration on the oscillating body and one can observe no vibration mode shape during experiment. In case of the FEA method, it is difficult to define boundary conditions correctly if the shape of a body tested is complex, and one can just obtain vibration mode shapes on the peak amplitude in each modes. In this study, plane plate of stainless steel(STS304), isotropic material, that is used as structural steel is analyzed about vibration characteristics under tension. Also, in the study of stainless steel, the characteristics of composite material(AS4/PEEK) used as high strength structural material in aircraft is evaluated about vibration under tension, and studies the effect of tension on vibration.

• Journal of the Korean institute of surface engineering
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• v.42 no.1
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• pp.53-57
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• 2009

Recovery of heavy-metallic component from a waste solution of factory was undertaken by the solar cell electricity. The solution was obtained from an electrolytic etching process of 316L stainless steel. The electrolysis of the solution for recovery of heavy metallic components was made with platinum plated titanium mesh anode and copper plate cathode. Analysis for the solution and electro-winned materials were made by EDS, XRD and SEM. Iron, chromium, and sulfur components were recovered on the cathode from the solution. Result of EDS analysis for the electro-winned materials revealed that some metal oxide were contained in the recovered material. The recovered materials were expected to have metallic form only by the electrolysis, but metal compounds were contained because of weak solar cell power. Nickel and manganese component in the solution doesn't recovered by this electrolysis process, but they made a sludge with phosphoric acid in the solution.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.861-865
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• 1998

A plate-type linear ultrasonic motor using logitudinal and bending multi-vibration mode was designed and fabricated for the application to card-forwarding device. The stator consisted of PZ-PT-PMS piezoelectric ceramic plate and stainless steel. The performances of the motor were measured. As the experimental results, no-load speed of the motor was 0.6m/s when applied voltage was $80\textrm{V}_{rms}$ in resonance frequency. Starting torque was 1.4 mNm and maximum efficiency was 1.2%.

• Journal of Welding and Joining
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• v.5 no.4
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• pp.22-27
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• 1987

The debonding of clad steel was often occurred at interface between stainless steel and carbon steel during the fabrication of pressure vessel. In order to clarify the causes of debonding phenomena, the fabrication sequences were fully analyzed. As a result, possible factors were noticed for causing the debonding of clad steel, that is, thermal treatment on weldment and welding. Moreover the existence of hydrogen diffused from surroundings also expedites the debonding of clad steel. In this stud, the effect of welding thermal cycle, hydrogen and mixed condition under thermal treatment on the interfacial strength of clad steel were investigated to understand the debonding mechanism of clad steel. From this study, it has been confirmed that the interfacial strength of clad steel was remarkablely deteriorated due to welding and/or existence of hydrogen under thermal treatment. In the case of welding thermal cycle effect, the higher temperature at interface experienced by welding, the more reduction in interfacial strength of clad steel resulted in. And the existence of diffusible hydrogen also reduced the interfacial strength. It is also found that the interfacial strength of clad steel became much lower value than that of the as-received plate under coexistence of above mentioned factors.