• 월간 기계설비
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• s.256
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• pp.66-67
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• 2011

스테인레스강은 철과 니켈, 크롬이 주 성분이다. 그 중에서 니켈이 차지하는 비율은 304계열 제품의 경우 8%에 불과하다. 그런데 STS 파이프 등 스테인레스 스틸 제품 원가의 60%를 차지하는 것이 니켈 가격이다. 결국 니켈 가격이 스테인레스 스틸 제품 가격을 좌지우지한다고 볼 수 있다. 우리 설비건설분야에서도 스테인레스 관련 제품이 공종에 따라 많이 투입되는 경우가 있다. 이번 호에서는 니켈의 국제 시세를 중심으로 스테인레스 제품 가격을 분석해 보고자 한다.

• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.385-390
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• 2016

In our study, ceramics coatings by additives of nano alumina and magnesia have cured on 304 stainless steel at $170^{\circ}C$ 2h. We designed and experimented the coated specimens that were characterized by laser induced fluorescence spectroscopy using the charge coupled device and scanning electronic microscopy(SEM). The result was revealed the ceramic coatings added fillers has more excellent on adhesive property and scratch resistance, and less weight loss in acid solution than ceramic coatings non-added fillers. Therefore, this study has designed and manufactured the electromagnetic spectrometry with CCD and then analyzed the coatings on 304 stainless steel using the High Resolution Charge Coupled Device in improving the corrosion resistance of 304 stainless steel. Nowadays, coatings of stainless steel have increased by industrial demand in hygienes, aviation, instrumentations and robotics as the industry special application develops.

• Tunnel and Underground Space
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• v.22 no.3
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• pp.221-225
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• 2012

Magnesium is one of the light weight materials, which can improve fuel economy and reduce emissions in automotive industry. Recently, magnesium alloys have gained considerable attention due to good mechanical properties. In this work, we have performed an explosive welding using the magnesium alloys (AZ31) and stainless steel (SUS 304). As a result, SUS304/AZ31 were successfully combined each other; however, a resolidified interlayer was observed at the point of welded layer. To reduce the resolidified interlayer, we have changed the thickness (0.5 mm and 1 mm) of stainless steel, distance (45 mm and 60 mm) between explosive and the center of materials and initial angle ($20^{\circ}$ and $30^{\circ}$) of explosive. In the case of the thickness 0.5 mm and angle of $30^{\circ}$, the resolidfied interlayer was not observed due to the increase of distance from the explosive. To accurately estimate the resolidified interlayer, electron probe micro-analyzer (EPMA) method and hardness were used. For the EPMA analysis, mixed materials were confirmed at the resolidified interlayer, and the measurement exhibited the middle value compared with the AZ31 and SUS304.

• Applied Chemistry for Engineering
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• v.31 no.2
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• pp.215-219
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• 2020

In this study, nanoporous iron oxide layers were fabricated by the anodization of 304 series stainless steel. K₂HPO₄/glycerol solution was used as an electrolyte for anodization. We investigated the anodization behavior according to various parameters such as electrolyte concentration, reaction temperature, applied voltage, and reaction time. As a result of anodization, we confirmed that the anodic growth rate of oxide layer on 304 series stainless steel increased with increasing the electrolyte temperature and applied potential. In order to form well-ordered porous nanostructures, the electrolyte temperature was at 160 ℃, and the applied potential was at 30 V in 10 wt% K₂HPO₄/glycerol electrolyte.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.3
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• pp.134-140
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• 2008

Micro electrochemical machining (ECM) is conducted on stainless steel 304 using non-toxic electrolyte of citric acid. Electrochemical dissolution region is minimized by applying a few hundred second duration pulses between the tungsten SPM tip and the work material. ECM characteristics according to citric acid concentration, feeding velocity and electric conditions such as pulse amplitude, pulse frequency, and offset voltage are investigated through a series of experiments. Micro holes of $60{\mu}m$ in diameter with the depth of $50{\mu}m$ and $90{\mu}m$ in diameter with the depth of $100{\mu}m$ are perforated. Square and circular micro cavities are also manufactured by electrochemical milling. This research can contribute to the development of safe and environmentally friendly micro ECM process.

• Proceedings of the KWS Conference
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• 2007.11a
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• pp.158-160
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• 2007

The butt and lap configurational friction stir welding of type 304 stainless steel was conducted in this study. The sound joints were obtained by WC tool. As the welding distance increased, tool deformation gradually increased at the pin edge. The discoloration by oxidation was observed at the top surface of the joint, a sufficient heat-input was required to avoid the welding defect owing to the lack of stirring at the welding start point. Very fine grains were observed in the stir zone, and the grain coarsening was not observed in the heat affected zone.

• Journal of Power System Engineering
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• v.8 no.2
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• pp.39-44
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• 2004

The effects of the STS 304 hollow cylinder property variations on the non-steady heat conduction are considered in this paper. In the non steady state, the specific heat and conductivity are depended on the temperature variations, and these properties affect to the governing equation on heat conduction. But the most of numerical analysis on heat conduction is assumed to constant properties which is conductivity and specific heat. Assuming that the properties are reacted sensitively, the numerical results can have the difference of between constant properties with non constant properties. The main parameters are specific heat and conductivity. The temperature distributions of the STS 304 hollow cylinder became in steady state after 4 minutes in case of the constant properties. As the conductivity is varied with temperature, the temperature distributions became in steady state after 15 minutes. Therefore, a numerical analysis of the non steady state heat transfer is so important in case of varying temperature.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1552-1557
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• 2004

This paper introduced about characteristics on the non-steady heat transfer of STS 304 hollow cylinder, In the non-steady state, the specific heat and conductivity are depended on the temperature variations, and these properties affect to the governing equation on heat conduction. But the most of numerical analysis on heat conduction is assumed to constant properties which is conductivity and specific heat. Assuming that conduction is assumed to constant properties which is conductivity and specific heat. Assuming that the properties are reacted sensitively, the numerical results can have the difference of between constant properties with non-constant properties. The main parameters are specific heat and conductivity. The temperature distributions of the STS 304 hollow cylinder became in steady state after 4 minutes in case of the constant properties. As the conductivity in varied with temperature, the temperature distributions became in steady state after 15 minutes. Therefore, a numerical analysis of the non steady state heat transfer will has to apply that conductivity varied with temperature.

• Journal of the Korean Applied Science and Technology
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• v.29 no.2
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• pp.317-322
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• 2012

The microstructures were examined by SEM, FT-IR spectra, tensible properties mole % of [NCO/OH], and particle size analyzer. Growing concerns in the environment-friendly industries have led to the development of solvent-free formulations that can be cured. We had synthesized the polyurethane resin having the ability to protect stainless steel against corrosion. Compared with general packing materials and coatings, this resin is highly stronger in intensity and longer durability. Polyurethane resins were composed of polyols, IPDI, silicone surfactant, catalyst and crosslink agent. Moreover, thermal fillers such as $Al_2O_3$, fume silica and $ZrO_2$ not only accelerated the curing rate but also improved the physical property as thermal barriers. The rigid segments of polyurethane in mechanical properties were due to crosslink agent and the increase of [NCO/OH]. In conclusion, the polyurethane microstructure with crosslink agent can be good material for themoset coating of metal substrates such as stainless steel.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.511-511
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• 2012

핵 융합로는 고밀도, 고에너지 플라즈마에 지속적으로 노출되며 고열부하 및 중성자, 플라즈마 이온에 의한 물성변화에 대한 다양한 핵 융합로 구축 재질의 실험데이터가 요구된다. 특히 핵 융합 반응의 핵심연료인 삼중수소의 재질별 누설거동 특성은 삼중수소의 블랑켓에서의 증식율, 열 교환기 및 공급과 회수과정에서의 손실율, 저장, 취급 및 차폐 등의 계산에 활용되므로 핵 융합로의 안전성과 경제성 확보 측면에서 매우 중요하다. 따라서 핵 융합로 구축 재질 선정시 삼중수소의 누설거동 특성은 반드시 고려되어야 한다. 본 연구는 삼중수소 누설거동 특성 해석을 위한 기초실험으로, 수소동위원소를 사용하는 누설거동실험 장치를 설계 제작하여 누설 거동실험을 수행하였다. 누설 가스로는 수소를 사용하였고, 시편은 스테인레스 스틸(SUS-304)을 사용하였으며, 시편의 가열온도는 500, 600, 700, $800^{\circ}C$에서 각각 수소누설거동 실험을 실시하였다. 수소에 대한 SUS-304 재질의 permeability, diffusivity, solubility에 대한 실험 결과를 발표하고자 한다.