• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2004.04a
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• pp.31-31
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• 2004

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.131.2-131.2
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• 2007

• Proceedings of the KWS Conference
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• 2002.05a
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• pp.185-187
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• 2002

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.153-154
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• 2006

• Journal of Advanced Marine Engineering and Technology
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• v.13 no.2
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• pp.43-63
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• 1989

Various kinds of corrosion prevention methods have been developed. It is known that the method of electrochemical protection is more effective and economical than any other method on the large scale metal structures in corrosive solutions. Strong acid solutions such as nitric and sulfuric acid solutions are often used in industries, and the expensive stainless steel is almost exclusively used for the equipment that comes in contact with such acid solutions. However, it is more reasonable that carbon steel is used rather than stainless steel depending upon concentration of those acid solutions from the economical viewpoint. In this study, the typical strong acid solution such as nitric and sulfuric acid solutions are chosen for the experiment and the selected materials of specimen are the stainless steels of SUS 304L and SUS 316L, the carbon steels of SS 41, SM 50 and RA 32, and highly pure lead. Electrochemical protection diagrams can be drawn with data from the external cathodic and anodic polarization curves of SUS 304L, SUS 316L and SM 50 steels in 5-60% nitric acid solutions and from those polarization curves of SS 41, RA 32, SM 50 and SUS 316L steels, and highly pure lead in 2.5-98% sulfuric acid solutions at the slow scanning rate. The data obtained with using the determination method of the optimum cathodic protection potential, the Tafel extrapolation method and the characteristics of anodic polarization curves. The main results obtained from the diagrams are as follows: 1) In nitric acid solution : (1) Corrosion potentials exist in each of those corrosion zones on the stainless steels in the lower concentration than about 12% solutions and on the high tensile strength steels in the lower concentration than about 30% solutions, but the corrosion current (density) in each zone is small on the above mentioned former steels and large on the latter ones. (2) The stainless steels can be self-passivated in the higher concentration than 15% solutions, and the high tensile strength steels gives rise to the same phenomenon in the higher concentration than 35% solutions. (3) The stainless steels in the lower concentration than 60% solutions and the high tensile strength steels in the higher concentration than 35% solutions can be used without protection, but the latter steels must ve protected anodically in the lower conccentration than about 30% solutions. 2) In sufuric acid solution : (1) The carbon steels can be self-passivated in the higher concentration than 45% solutions, and the SUS 316L steel in higher concentration than 75% solutions and the lead in all concentration solutions also gives rise to the same phenomenon. (2) The lead in the lower concentration than 80% solutions and the SUS 316L steel in the higher concentration than 80% solutions can be used without protection. (3) The carbon steels in the higher concentration than 50% solutions also can be used without protecting economically, but the SUS 316L steel in the 20-70% solutions are considerably corrosive without protecting anodically.

• Journal of the Korean Society for Nondestructive Testing
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• v.19 no.4
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• pp.270-276
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• 1999

Fourier transform has been one of the most commonly used tools in study of frequency characteristics of signal. However, based on the Fourier transform. it is hard to tell whether a signal's frequency contents evolve in time or not. Recently, to overcome Fourier transform fault. not to represent non-stationary signal, time-frequency analysis methods are developed and those can represent informations of signal's time and frequency at the same time. In this study we analysed ultrasonic signal for degraded SUS 316 with time-frequency analysis method. In particular the methods such as short time Fourier(STFT) and Wigner-Ville distribution(WVD) were used to extract frequency contents and characteristics from ultrasonic signals.

• Transactions of the Korean Society of Mechanical Engineers
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• v.4 no.4
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• pp.152-159
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• 1980

The temperature and the grain boundary precipitation have the great influence on the low-cycle fatigue behavior of austenite stainless steel at elevated temperature. For the purpose of investigating the mechanism concerning the change of fatigue micro crack mode in SUS 316 under various conditions low-cycle fatigue test was carried out at the elevated temperature 600.deg.C, plastic strain range 2% and constant strain rate .5c.p.m. A special attention is given to the observation of intergranular crack initiation. The results obtained are summarized as follows. The low-cycle fatigue behavior of SUS 316 at 600.deg.C is affected by transition of crack initiation mode from intergranular to transgranular. The transition is due to the aging effect, which is caused by grain boundary precipitations of Cr$\_$23/C$\_$6/. Since the intergranular crack initiation is brought about by the grain boundary sliding, the transgranular crack initiates in case that the strengthening of grain boundary due to the precipitation of Cr$\_$23/C$\_$6/ carbides takes place ahead of the intergranular crack initiation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10b
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• pp.36-39
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• 2003

Due to the strength and biocompatibility requirement, the stainless steel SUS 316L is widely used for trauma internal fixation device. SUS 316L can be hardened and strengthened only by cold work. In this work, the material compression test is performed both in laboratory and computer simulation by a FEM analysis software DEFORM to correlate the hardness to strain. This data is then used for preform design and predict the hardness of the finish bone plate forging. Finally, we compared the hardness between the actual forging and computer analysis results. Although the predicted hardness from computer simulation. is 55HV higher than the final forging sample, we can get good compatibility on the hardening tendency of cold forging.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.2
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• pp.142-146
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• 2012

In the geothermal power, the geothermal fluid such as water or steam is moved from the ground to turbine a pipeline. Because the geothermal fluid with high temperature contains Cl-and SO4-, It cause to diminish the system lifetime due to the increase in the corrosion of pipeline. In the present work, the characteristics of corrosion and its fatigue of the sus316 which is used in the pipeline are evaluated experimentally. From this study, the following results can be obtained; for the case of the corrosion environment, it is found that the corrosion rate is faster than that of the steam environment by 10 to 30 times, and the corrosion fatigue limit is underestimated compared to that of steam state.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.540-541
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• 2006

SUS316L stainless steel, commercial pure Titanium and Ti-6Al-4V alloy powders applied by Mechanical Milling (MM) process are sintered by Hot Roll Sintering (HRS) process. Microstructure and mechanical properties of those HRS materials is investigated. The microstructures of materials produced by HRS process consist of fine grains and work-hardened structure, that is, the hybrid microstructure. Tensile test of the HRS material demonstrated the good mechanical properties. These results show that the HRS process is very effective to the improvement of mechanical properties in the SUS316L stainless steel, commercial pure Titanium and Ti-6Al-4V alloy.