• 한국기계가공학회지
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• 제8권3호
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• pp.33-37
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• 2009

Manifold could apply stainless steel with light weight and durability to improve fuel efficiency at automotive industry. This study is analyzed and compared by heat transfer and deformation according to the materials of cast iron and stainless steel. The heat transfer at manifold of cast iron at the distribution of heat temperature is more than that of stainless steel. But the value of maximum heat deformation in case of stainless steel is 1.5 times as great as that in case of cast iron. The value of maximum heat equivalent stress in case of stainless steel is 2.7 times as great as that in case of cast iron. This maximum stress at manifold is shown at the part assembled with engine body.

• 보존과학연구
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• 통권21호
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• pp.101-118
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• 2000

Stone cultural properties(pagoda, Buddhist statue etc.) is moved in original place for many reasons and restored after taking to pieces for structural safety. With the movement and restoration after taking to pieces, the cast iron is used for the sake of a fixation and horizontality. The stone cultural properties are spoiled the beauty and accelerated the weathering because of the corrosion product of cast iron. So we need to substitute for the improved property in all aspects. We are executed the corrosion test and inquired the property of material on the usable material for the shim of stone cultural properties. That is the Cast iron, Stainless steel, Titanium and Fiber Reinforced Plastics. In the result of the physical property and strength, the Stainless steel and Titanium was superior to the Cast iron. And the Stainless steel and Titanium was slower than the Cast iron in the corrosion velocity for the acid, salt and rain. If the shim is substitute the Stainless steel or Titanium for the Cast iron, the stone cultural properties are able to reduce the pollution of stone cultural properties by corrosion product and should not happen in the matter of stone pagoda.

• 한국주조공학회지
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• 제18권5호
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• pp.467-473
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• 1998

For enhancing the mechanical properties of LTE (low thermal expansion) cast steel, systematic researches have been carried out. The effects of alloying elements such as vanadium, molybdenum and carbon on the hardness and linear thermal expansion coefficient were investigated. In the range of $0.5{\sim}2.3\;wt%$ carbon, addition of 1.73 wt% carbon caused hardness increase due to the formation of eutectic carbide having high hardness but over the range of 1.73 wt% carbon, hardness was decreased. Thermal expansion coefficient increases with carbon contents. In the LTE cast steel containing 0.6 wt% carbon, hardness increased up to 1.96 wt% vanadium addition. But over the range of 1.96 wt% vanadium hardness was decreased by coarse eutectic carbide. Thermal expansion coefficient of LTE cast steel containing 0.6 wt%carbon moderately increased with increasing vanadium contents. There was no significant variation of hardness and thermal expansion coefficient according to molybdenum content in LTE cast steel.

• 대한금속재료학회지
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• 제49권10호
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• pp.774-779
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• 2011

S-N fatigue behavior of cast 304 stainless steel was studied at 25, -50 and $-196^{\circ}C$ and at a stress ratio of -1 in uniaxial and bending loading condition. It was found that the resistance to S-N fatigue was greatly improved with decreasing testing temperature. The normalized S-N fatigue curves by tensile strength at three different testing temperatures matched each other, suggesting that tensile strength determines the S-N fatigue resistance of cast 304 stainless steel at low temperatures. The effects of different loading on the resistance to S-N fatigue of cast 304 stainless steel were quantified. The S-N fatigue curves at 25, -50 and $-196^{\circ}C$ were described by using Basquin's law the relationship between the S-N fatigue curve and the testing temperature was obtained by using a simple regression method.

• 보존과학회지
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• 제28권4호
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• pp.367-376
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• 2012

철기 생산 기술은 당시 사회 발전을 가늠하는 척도로서 과거의 제철 방법을 이해하기 위한 철기 유물의 미세조직과 개재물에 대한 다양한 연구가 진행되고 있다. 본 연구에서는 고려시대로 추정되는 고양 벽제 제철 유구에서 일괄로 수습된 철제 유물의 시편을 채취하여 광학현미경과 미세경도시험기, SEM-EDS를 이용하여 미세 조직의 성분분석을 통해 제철과 제련 기술을 추론하여 보았다. 연구결과 철괴는 주철괴와 탄소강 철괴로 분류되었다. 주철괴의 경우 백주철 조직과 인(P)의 함량이 높은 회주철 조직으로 분류되었으며 회주철 내 높은 P의 함량은 석회질 등의 융제가 첨가되며 혼입된 것으로 판단된다. 따라서 주철 조직의 철괴 및 고탄소강 철괴는 제련공정을 거치지 않은 선철들로 추정된다. 또한 철기 제작에는 크게 두가지 방법이 사용된 것으로 판단된다. 첫번째는 주물에 주철을 부어 제작하는 주철괴 제작 방법이며, 두번째는 선철의 제련 공정을 통하여 생산되는 탄소강을 제작하는 방법이다. 특히 탄소강의 고른 강 조직과 적은 양의 MnS 개재물은 현대 제철 조직과 매우 유사한 특징을 지니나 고양 벽제 제철유구에서 수습된 탄소강 내 Mn의 함유에 대하여 판단하기에는 좀 더 많은 연구가 이루어져야 할 것이며, 주철의 제강공정을 통한 고탄소강의 생산 가능성도 염두에 두어야 할 것으로 사료된다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.118-123
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• 2004

Cast austenitic stainless steel have been widely used for primary coolant piping in light water reactors. This material is subject to thermal embrittlement at reactor operating temperature. CF-8M and CF-8A cast austenitic stainless steel is used for several components, such as primary coolant piping, elbow, pump casing, and valve bodies in light water reactors. Thermal embrittlement results in spinodal decomposition of delta-ferrite leading to decreased fracture toughness. In this study, the specimens were prepared using an accelerated aging method. The measurement of ferrite content, Charpy impact test and J-R test were performed to verify the predicting equation for aged material properties. In case of above 25% ferrite content, predicted result of J-R curve might be non-conservative.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.131-136
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• 2003

CF8M cast austenitic stainless steel is used for several components such as primary coolant piping, elbow, pump casing, and valve bodies in light water reactors. These components are subject to thermal aging at the reactor operating temperature. Thermal aging results in spinodal decomposition of the delta-ferrite leading to increased strength and decreased toughness. In this study, three kinds of the aged CF8M specimen were prepared using an artificially simulated aging method. The objective of this study is to summarize the method of estimating ferrite contents, Charpy impact energy and J-R curve, and to evaluate the thermal embrittlement of the CF8M cast austenitic stainless steel piping used in the domestic nuclear power plants.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.96-101
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• 2004

Cast austenitic stainless steel is used for several components, such as primary coolant piping, elbow, pump casing and valve bodies in light water reactors. These components are subject to thermal embrittlement at the reactor operating temperature. The objective of this study is to summarize the method of estimating ferrite content, Charpy impact energy and J-R curve and to evaluate the thermal embrittlement of the cast austenitic stainless steel piping used in the domestic nuclear power plants. The result of evaluation, two domestic nuclear power plants used CF-8M and CF-8A material has adequate fracture toughness after saturation.

• 한국주조공학회지
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• 제8권4호
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• pp.429-436
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• 1988

The influences of some casting conditions on bonding ratio and state at bonding zone of stainless steel-cast iron dual tube produced by centrifugal casting process were investigated to estimate fabrication technics. 1) Bonding ratio is increasing such as increasing of inner surface temperature of outer metal(stainless steel STS 304), if pouring temperature of inner metal (cast iron) is constant. 2) The more pouring temperature of inner metal (cast iron) increase, the more bonding ratio increase when inner surface temperature of outer metal (cast iron) is constant. 3) As the mold rotary speed is increase, the hatching area of bonding map (perfect bonding area) goes down to the low pouring temperature of inner metal. 4) In order to predict bonding state of two different metal, we are able to make and use the bonding map about casting conditions such as inner surface temperature of outer metal, pouring temperature of inner metal and mold rotary speed.

• 한국주조공학회지
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• 제25권3호
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• pp.134-141
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• 2005

To overcome the undesirable deformation, peeling off and geometrical restrictions which were mainly caused by differences in thermal expansion coefficients during the cladding of aluminum strip and stainless strip, new processing method based on vacuum die casting is designed and implemented in fabricating Al/Fe-17wt%Cr steel(stainless steel). To increase cast-bonding ability, the surface of Fe-17wt%Cr steel is electrochemically etched to have optimum pit size and density. The optimum conditions to generate best pit are as follows: Solution: 1 M $Fecl_{3}$+1 M Nacl, Addition: $CuCl_{2}+HCl$, Current density: 80 $mA/cm^{2}$, Total current: 400 $coulomb/cm^{2}$, AC frequency :60 Hz.