계산역학과 초음파 탐상을 이용한 역문제 해석에 관한 연구

김윤채,이성룡,조석수 三陟大學校 1999 論文集 Vol.32 No.1

Quantitative nondestructive evaluation(QNDE) gets hold of position and pattern of defects in mechanical components and estimates safety of structure. The ultrasonic defect detection out of QNDE is based on refraction of ultrasonic wave by defects in solid material. Neural network is information processing system modeling human brain and has an application to defect identification with ultrasonic defect detection. The present method consists of three process. The first process gets sample data on defect and ultrasonic wave parameters according to various defect patterns. In the second process, Neural networks is learned using sample data. In the third process, neural networks predicts defect patterns by unlearned data. This processes are applied to the identification of size and location of defects hidden in SM45C.

인공지능기법을 이용한 맞대기용접부의 잔류응력 예측시스템 개발

김윤채,성백섭 조선대학교 생산기술연구소 2006 生産技術硏究 Vol.28 No.2

In this study, it is developed that the system for effective prediction of residual stresses by the backpropagation algohthm using the neural network. To achieve this goal, the series experiment were carried out and measured the residual stresses using the sectional method. Using the experimental results, the optional control algorithms using a neural network should be developed in order to reduce the effect of the extemal disturbances duhng GMA welding processes. Then the results obtained from this study were compared between the measured and calculated results, weld guality might be controlled by the neural network based on backpropagation algorithm.. This system can not only help to understand the interaction between the process parameters and residual stress, but also improve the quantity control for welded structures.

Fe-Sn系 燒結合金의 諸性質에 미치는 成形 및 燒結條件의 影響

박창선,김윤채 조선대학교 생산기술연구소 1998 生産技術硏究 Vol.20 No.1

Effects of compacting and sintering conditions on the properties of iron-tin sintered alloy for porous bearings were investigated in comparsion with those of iron compact. The results obtained are as follows. 1. The effect of compacting condition : When the green porosity becomes higher, the compact shrinks considerably but on the contrary. the pore-structure grows much more and the strength decreases largely. Therefore, in order to take the sintered compact having over 18vol% of the intercommunicating porosity and over 17kgf/㎟ of the radial crushing strength which are prescribed values for the sintered iron compact in JISB1581, the green porosity must be kept within 18~30% at the compacting. 2. The effect of sintering condition : When the sintering temperature becomes higher, the compact shrinks considerably but the pore-structure does not almost changed. On the other hand, the strength increases much more. And when the keeping time at the sintering temperature of about 1150℃ is longer, the compact shrinks considerably but on the contrary. the pore-structure becomes poor a little and the strength increases. Therefore, it is desirable sintering condition that the sintering temperature is about 1150℃ and keeping time is within 30 ~ 60min. As the results. compacting and sintering conditions of iron-tin sintered alloy can be detemined as follows. When tin powder having -350mesh of particle size is added about 1.0% into iron powder and compacted to about 22% of green porosity and then. sintered at 1150℃ for about 30min. the alloy will have following properties ; the dimensional change is about -0.2%, the intercommunicating porosity is about 20vol% and the radial crushing strength is about 30kgf/㎟ which are much better than the properties of the conventional sintered iron for porous bearing.

Fe-Cu계 합금분말을 이용한 Fe-Cu-Sn계 소결합금의 제성질

원용신,김윤채 三陟大學校 産業科學技術硏究所 2000 産業科學技術硏究論文集 Vol.5 No.-

In order to reduce the sintering temperature of iron based sintered parts, sintering properties of iron-copper-tin compact made from iron-copper prealloyed and tin powders were investigated at various temperatures in the range 700∼890 ℃, and then the results were compared with those of the conventional iron-coper-tin compact made from iron, copper and tin powders. The results obtained are as follows : 1) Sintered density ratio and radial crushing strength of iron-copper-tin compact made from iron-copper prealloyed and tin powders were higher than those of the conventional iron-copper-tin compact made from iron, copper and tin powders at all sintering tempeatures. 2) The radial crushing strength of iron-copper-tin sintered compact made from powder mixture, of which iron-7.20%copper prealloyed powder mixed with 1.80% tin powder in the copper and tin ratio 8 : 2, was obtained about 50kg/㎟ at the lowest temperature studied 700˚C for 30min, and this increased to about 60kg/㎟ after sintering at 890˚C for 30min. 3) The radial crushing strength of iron-copper-tin sintered compact made from iron, copper and tin powders mixture as the conventional method, also its chemical composition was same with in case of using above the iron-7.20%copper prealloyed powder, was obtained about 23kg/㎟ at 700˚C for 30min, and this increased to about 43kg/㎟ after sintering at 890˚C for 30min. As the result, the using of iron-copper prealloyed powder improve its sintering performance permitting lower sintering temperature more than conventional metnod.

Fe-Sn系 燒結合金의 諸性質에 미치는 Sn粉의 粒度 및 配合量의 影響

홍범식,김윤채 三陟大學校 1997 論文集 Vol.30 No.1

Effects of particle size and content of tin powder on the properties of iron-tin sintered alloy for porous bearing were investigated in comparison with those of iron powder compact. The results obtained are as follows; 1) The effect of particle size of tin powder : When the particle size becomes finer, the compact shrinks a little and pore-structure becomes finer and then, the strength increases considerably. 2) The effect of tin powder content : When content of tin powder increases, the compact expands a little and also the pore-structure grows a little. But the strength decreases especially with increasing of the tin content above 1.5wt&. Therefore, it is desirable that the particle size is -350mesh and the content is about 1.0wt%.

망간 용해액의 정제를 위한 기초 연구

신강호,송영준,김윤채 三陟大學校 1998 論文集 Vol.31 No.1

This study was performed to obtain basic data for refining manganese nitrate solution which used as starting material for manufacturing Mn₃O₄, raw material of Mn-Zn soft ferrite. 1. Among the various kinds of manganese oxide, MnO is most appropriate for making manganese nitrate solution, for the MnO is easily dissolve in nitric acid and which reaction is exothermic. 2. The most appropriate condition for reduction roasting which reducing Mn₃O₄to MnO is temperature of 700~800℃, roasting time of 30~60min, carbon 5~10 wt.%. 3. The appropriate pH of solution and reaction time for removing iron and silicon from manganese nitrate solution by controlling the pH of solution are pH4~6, 1~2hour, respectively. 4. The appropriate condition for removing calcium and magnesium from manganese nitrate solution by precipitating in the form of oxalate are pH of 1~4, (NH₄)₂C₂O₄adding amount of 0.1M or less and as long reaction time as possible.

합금철 분진의 재활용을 위한 기초 연구

신강호,송영준,김윤채 三陟大學校 1998 論文集 Vol.31 No.1

This study was performed to obtain the basic data for recycling of the dust in ferroalloy manufacture. The chemical composition, composition material, particle size and shapes of the bulk dust, sizing dust and magnetic separating dust were investigated. As the result, the dust from High Carbon Ferromanganese Manufacturing Process is not sufficient as source material of Mn, the dust from Bag Filter of AOD Process is a good source material of Mn, and the dust from Cooler of AOD Process can be a good source material of Mn through Sizing or Magnetic Separation.

Expansion Behavior of Iron-Copper Compact from (FeCu) Pre-Alloyed Powder

Kim, Youn Che,Suk, Myung Jin Scientific.Net 2007 Materials Science Forum Vol.534-536 No.1

<P>Dilatometric curves of iron-copper compact made from elemental or pre-alloyed powder were compared in order to study its expansion mechanism. The compacts from a mixture of elemental iron and copper powders showed the maximum expansion at the copper powder content of 7.44mass% and at the sintering temperatures above the copper melting-point. In the case of the compacts from a mixture of iron pre-alloyed powder of (Fe- 3.44mass%Cu) and copper powder, the maximum expansion which is lower than the former case was obtained at the additive copper powder content of 4.00mass%. But the compact from a mixture of iron pre-alloyed powder of (Fe-7.18mass%Cu) and copper powder showed only shrinkages at any additive copper powder content. The penetration of liquid copper into the interstices between solid grains was observed in all sintered compacts. The iron-copper compacts containing the same content of copper powder showed a very different expansion behavior depending on the amount of copper content in the starting iron raw powder.</P>

Expansion Behavior of Iron-copper Compact Made from (Fe-Cu) Prealloyed Powder

Kim Youn-Che,Suk Myung-Jin 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

Dimensional change of compact made from (Fe-Cu) prealloyed powder and copper powder compared to that of compact made from iron-copper elemental powder. The compact made from the prealloyed powder with a copper content of 7.18mass% which is nearly equal to its solution limit and copper powder showed only the large contraction in spite of penetration of liquid copper into grain boundary of the prealloyed powder. But the compact made from iron-copper elemental powder showed the large expansion in spite of same chemical composition with former case.

Mn3O4 분진으로부터 고순도 훼로망간 제조에 관한 연구

김윤채 ( Youn Che Kim ),송영준 ( Young Jun Song ),박영구 ( Young Koo Park ) 한국유화학회 2011 한국응용과학기술학회지 Vol.28 No.2

In order to make high-purity ferro-manganese from Mn3O4 waste dust, the application of aluminothermite process to the reduction of the waste dust was investigated. The mixture from Mn3O4 dust as metallic source and Al metal powder as the reductant ignited, and reduced with an extremely intense exothermic reaction. The rapid propagation of the aluminothermite reaction occurred spontaneously and stably by ignition of the mixture. The Manganese having some alloy elements emerged as liquids due to the high temperatures reached up to about 2,500°C and separated from the liquid by their differences of specific gravity. The result of thermite reaction showed the fact that can be obtained high purity ferro-manganese which have over about 90% of manganese content and lower impurities such as C, P, S than those of KS D3712 specification. The recovery of manganese from Mn3O4 dust was lower level of about 65% than about 75% from manganese ore by electric furnace process, that is due to spatter loss because of its extremely intense thermite reaction. But it will be improved by the process designed to provide CaO as the cooler or to use the Al metal powder having larger particle size distribution.