• 한국기계가공학회지
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• 제21권6호
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• pp.98-106
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• 2022

Among the parts assembled in the gas receiver of a marine engine, the titanium alloy stainless steel (STS 316Ti) wire mesh serving as a filter was broken, and the related part, the turbine fan of the turbocharger, was damaged. In this study, a sample of the grid wire mesh was collected and the cause of breakage was analyzed, and a method of minimizing the dent mark caused by the mold during wire forming, which is one of the most direct causes, was studied. In addition, the optimum mold shape was realized through FEM simulation, and the wire wave molding machine capable of controlling the speed was improved by supplementing the problems of the existing wire wave molding machine, thereby improving durability with minimal dent marks.

• 대한금속재료학회지
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• 제47권2호
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• pp.79-90
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• 2009

A study has been made about the effects of powder content, reaction temperature, reaction time, and stirring speed on the preparation of the stainless steel(STS) 304L powders plating with copper by an electroless plating method. The behavior of corrosion resistance of the sintered STS-Cu composite powders was also investigated by the salt spraying test The electroless plating technique was an effective method to manufactur the copper-uniform plating composite powders, the corrosion resistance of this sintered specimen was improved bysuppressing Cr precipitates on grain boundaries in the sintered compacts of composite powders.

• 한국강구조학회 논문집
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• 제17권1호통권74호
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• pp.73-82
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• 2005

본 논문은 스테인리스강이 건축구조용으로 이용될 때 중심압축재와 기둥의 최대내력을 수치해석으로 조사한 것이다. STS304의 소재인장시험결과로부터 응력-변형도 관계를 모델화하여 최대내력에 미치는 영향을 조사하였으며 강구조 한계상태설계기준식과의 비교를 시도하였다. 스테인리스강을 건축구조용으로 사용하기 위해서는 별도의 설계기준식이 필요하다는 점이 확인되었다.

• 동력기계공학회지
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• 제14권6호
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• pp.29-34
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• 2010

As the steam temperature of fossil power plant boiler is increasing, the use of 9Cr-1Mo high alloy material is prevalent and it is needed to investigate the characteristics of low cycle fatigue for high alloy and austenite stainless steel that has used up to recently. As a result of test, in 9Cr-1Mo high alloy steel, the relation of strain and fatigue life is non-linear and the crack mode of low cycle fatigue is brittle but in the austenite stainless steel, that of strain and fatigue life is linear and the crack mode of low cycle fatigue is ductile. Comparing the fatigue life between high alloy and austenite stainless steel, there is no consistent characteristics as to strains. But the fatigue life of 9Cr-1Mo steel is longer by 25% than that of STS304 stainless steel in the relatively low, 0.3% strain. In the other strain, the fatigue life of two materials is similar.

• 한국표면공학회지
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• 제40권5호
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• pp.234-240
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• 2007

As a reactor coolant pump (RCP) is operated in the nuclear power system for a long time, so its surface is continuously contaminated by radioactive scales. In order to maintain for RCP internals, a special chemical decontamination process should be used to reduce the radiation from the RCP surface. In this study, applicable possibility in chemical decontamination for RCP was investigated for the various stainless steels. The stainless steel (STS) 304 showed the best electrochemical properties for corrosion resistance and the lowest weight loss ratio in chemical decontamination process model 3-1 than other materials. However, the pitting corrosion was generated in both STS 415 and STS 431 with the increasing numbers of cycle. The intergranular corrosion in STS 415 was sporadically observed. The sizes of their pitting corrosion were also increased with increasing cycle numbers.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.6-14
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• 2007

The objective of this research is to comparative LCA(life cycle assessment) between two different model of Electric Motor Unit(EMU).the environmental impact of Aluminum body Electric Motor Unit(EMU) and Stainless Steel(STS) body Electric Motor Unit(EMU). LCA process consists of four steps which are goal, scope definition, life cycle impact analysis(LCIA) and life cycle interpretation. ISO 14044 provides the LCA standard method which can be conducted by using comparative LCA. From the research it is foung that the Aluminium Body Electric Motor Unit (EMU) is 3.6ton heaver than Stainless Steel(STS) body Electric Motor Unit(EMU). The system boundary of both Electric Motor Unit (EMU) are same life span and travel same distance. These both Electric Motor Unit (EMU) has same kind of environmental impact which is maximum Ozone Depletion(OD). During using period of these two models, the Aluminium Body Electric Motor Unit(EMU) has more global warming(GW) effect but Stainless Steel(STS) body Electric Motor Unit(EMU) has more Ozone Depletion(OD) effect. The above result is obtained by using LCA software PASS verson 3.1.3.

• 한국표면공학회지
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• 제44권4호
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• pp.149-154
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• 2011

Martensitic stainless steel STS 431 has been nitrided by active screen ion nitriding under the various temperature and time. The thickness of diffusion layer, case depth, hardness and composition phases were investigated using field emission scanning electron microscopy (FE-SEM), micro-Vickers hardness tester, X-ray diffraction (XRD) and glow discharge spectroscopy (GDS). It was observed that the thickness of diffusion layer depends strongly on the treatment temperature and time. A sample, which was nitrided at $450^{\circ}C$ for 8hours, was a maximum hardness of Hv0.01 1558 and nitride layer of $70{\mu}m$. As shown in XRD patterns, $\varepsilon(Fe_{2-3}N)$ and expanded martensite (${\alpha}_N$) phases which was saturated with nitrogen solid solution were in the nitrided layer treated at $450^{\circ}C$ for 2 hours. Composition phases of $\varepsilon$ $(Fe_{2-3}N)$ and ${\gamma}'$ ($Fe_4N$) were observed after active screen nitriding at $450^{\circ}C$ for 8 hours.

• 대한금속재료학회지
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• 제46권11호
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• pp.708-712
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• 2008

The influence of high temperature gas nitriding (HTGN) in STS347 and STS310S steels was experimentally investigated. The HTGN was carried out at $1,050^{\circ}C{\sim}1,150^{\circ}C$ for 10 hrs in a gaseous atmosphere containing $1kg/mm^2$ of nitrogen. After HTGN, fine precipitates of $Cr_2N$ and NbN appeared in austenite on the surface of STS 347, while nitrogen pearlite, which was layeredof $Cr_2N$ and austenite alternatively, appeared in austenite on the surface of STS 310S. The surface hardness of HTGN-treated, STS 347 and STS 310S specimens was 250~360 Hv and 270~400 Hv, respectively, depending on the temperature of HTGN. The nitrogen content was analyzed 1.4 wt% and 1.6 wt% at the surface layer of STS 347 and STS 310S steels, respectively. In addition, an improvement in the corrosion resistance of HTGN treated specimens was observed.

• 한국결정성장학회지
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• 제23권4호
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• pp.207-212
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• 2013

산업시설에는 용접된 구조물에 반복 하중이 발생하여 피로파괴가 발생하고 있는데 이 피로파괴를 줄이기 위해 일반구조용압연강재(SS400)와 스테인리스강(STS304)을 $CO_2$ 용접하여 기계적 특성 분석을 하였다. X-ray 촬영을 하여 결함검사를 하고 용접부에 결함이 없는 시험편으로 경도, 인장, 피로 시험을 하였다. 경도는 SS400과 STS304가 용접된 시험편이 SS304만 용접된 시험편보다 높게 나타났다. 그리고 인장강도와 항복강도는 반대로 SS304만 용접된 시험편이 높았으며 피로한도 또한 마찬가지였다. 따라서 $CO_2$ 용접을 할 경우 융점이 낮고 용접성이 좋은 SS400만으로 용접할 때 더 좋은 성능을 보여준다.

• 한국정밀공학회지
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• 제26권11호
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• pp.131-137
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• 2009

A pair of connectors for transferring torque is widely used in various types of a mechanical system. By the repetition of mechanical contact between a pair of connector, wear occurs easily. This kind of defect sometimes can cause a serious problem of health in case of the connector is used in a refrigerator. In this work, the material combination of connectors was experimentally studied to reduce the amount of wear; for the combination of connectors, various types of engineering materials including polyacetal, polycabonate, stainless steel (STS-304), NiP coated STS-304, and STS-310 were evaluated to check each wear behavior. Also an effective method of wear test was suggested for precise controlling of wear conditions such as contact area, contact force, and relative motion speed. From the test results, it was found out that a pair of polyacetal to STS-304 and STS-310 showed the lowest specific wear rates among other pairs.