CAD 영상 데이터 베이스를 위한 2차원 공간 관계 표현방법 ( Representation Method of 2 Dimensional Spatial Relationships for the CAD-Image Database )

주철홍,이상훈,이대영 한국통신학회 1994 한국통신학회 학술대회논문집 Vol.13 No.1

CAD 影像 데이타 베이스를 위한 2次元 空間 關係 表現方法

주철홍(CHUL-HONG JOO),이상훈(SANG-HUN LEE),이대영(DAE-YOUNG LEE) 한국통신학회 1994 한국통신학회 학술대회논문집 Vol.1994 No.7

저Pb Sn-5%Pb-1.5%Ag-x%Bi계 솔더 합금의 특성에 관한 연구

홍순국,주철홍,강정윤,김인배 대한용접접합학회 1998 대한용접·접합학회지 Vol.16 No.3

Recently as environmental pollution caused by Pb has posed a serious threat to the global environment, the trend to regulate the usage of Pb in electronic industry is one the rise. Currently, the solder alloy with high Pb content, Sn-37%Pb, is utilized in the electronic assembly therefore, the objective of this study is to develop an alternative solder alloy for the existing Sn-37%Pb solder alloy. First thing, this work choosed Sn-5%Pb-1.5%Ag, Sn-5%Pb-1.5%Ag-x%Bi(x=1~5%) for candidate solder alloys, and examined their properties such as melting range, wettability, microhardness, tensile property, oxidation behavior and microstructure. Wettability was on the same level of Sn-37%Pb. Dissolution of Pb ion in Sn-5%Pb solder was 0.46ppm. This solder alloy revealed cellular dendrite microstructure $\beta$-Sn matrix, Pb-rich phase, Ag/Sn, and Cu/Sn Intermetallic compounds. The range of solidification temperature was within 3$0^{\circ}C$. Also these alloy displayed higher tensile strength and lower elongation than Sn-37%Pb. The resistance of oxidation in Sn-5%Pb-1.5%Ag solder alloy was superior to that of Sn-37%Pb solder alloy. But that of Sn-5%Pb-1.5%Ag-5%Bi solder alloy was equal to that of Sn-37%Pb solder alloy.

저Pb Sn-5%Pb-1.5%Ag=x%In계 솔더 합금의 특성에 관한 연구

강정윤,주철홍,홍순국,김인배 釜山大學校生産技術硏究所 1998 生産技術硏究所論文集 Vol.54 No.-

Pb의 환경오염 문제를 발생하지 않는 저농도 Pb 솔더합금을 개발하기 위하여, 새로운 Sn-5%Pb-1.5%Ag-x%In계 합금 조성을 설계하고, 이 합금의 융점, 젖음성, 상분석, 경도, 인장강도, 드로스성을 평가하여, Sn-37%Pb 솔더와 대체 가능성을 타진하였다. Sn-5%Pb 솔더 합금의 Pb이온 용출농도는 국제규제치인 2ppm¹)보다 훨씬 적은 0.46 ppm이었고, 환경문제를 유발하지 않는 것으로 확인되었다. 이 합금계의 융점은 183∼192℃이고, 응고온도범위도 5℃ 내외로 매우 좁았다. 젖음성은 In의 첨가량에 따라 큰 차이가 거의 없었으며, Sn-37%Pb와 비슷하였다. 융점 및 젖음성 측면에서 Sn-37%Pb와 대체 가능한 것으로 판단되었다. 경도는 Sn-37%Pb의 약 1.5배이고, 인장강도는 Sn-37%Pb의 것보다 높고, In의 첨가량에 따라 증가하였지만, 연신율은 감소 하였다. In이 1% 첨가된 합금에서는 수지상정 경계에 Ag₃Sn과 Pb가 정출되고, 3%이상에서는 Ag₃Sn과 Ag₃In 및 Pb가 정출되었다. 드로스 생성속도는 Sn-37%Pb합금이 Sn-5%Pb-1.5%Ag합금보다 빠르고, In을 첨가할수록 느리고, 2%의 In을 첨가한 합금은 180분에서도 거의 드로스가 발생하지 않았다. Recently environmental pollution caused by 'Pb' has posed a serious threat to the global environment, the trend to regulate the usage of 'Pb' in electronic industry is on the rise. Currently, the solder alloy with high Pb content, 63%Sn-37%Pb, is utilized in the electronic assembly; therefore, the objective of this study is to develop an alternative solder alloy for the existing 63%Sn-37%Pb solder alloy. First thing, this work choosed Sn-5Pb-1.5Ag, Sn-5Pb-1.5AgBi(x=1 ∼ 5%) for candidate solder alloys, and examined their properties such as melting range, wettability, microhardness, tensile property, oxidation behavior and microstructure. Wettability was on the same level of 63%Sn-37%Pb. Dissolution of Pb ion in 95%Sn-5%Pb solder was 0.46ppm. This solder alloy revealed cellular dendrite microstructure, β-Sn matrix, Pb-rich phase, Ag/Sn, and Cu/Sn Intermetallic compounds. The range of solidification temperature was within 30℃. Also these alloy displayed a higher U.T.S and lower elongation than 63%Sn-37%Pb. The resistance of oxidation in Sn-5Pb-1.5Ag solder alloy was superior to that of Sn-37Pb solder alloy. But that of Sn-5Pb-1.5Ag-5Bi solder alloy was equal to that of Sn-37%Pb solder alloy.

저 Pb Sn-5%Pb-1.5%Ag-x%In계 솔도 합금의 특성에 관한 연구

홍순국,주철홍,강정윤,김인배,Hong, Sun-Guk,Ju, Cheol-Hong,Gang, Jeong-Yun,Kim, In-Bae 한국재료학회 1998 한국재료학회지 Vol.8 No.11

Pb의 환경오염 문제를 발생하지 않는 저농도 Pb 솔도합금을 개발하기 위하여, 새로운 Sn-5%Pb-1.5%Ag-x%In계 합금 조성을 설계하고, 이 합금의 융점, 젖음성, 상분석, 경도, 인장강도, 드로스성을 평가하여, Sn-37%Pb 솔더오 대체 가능성을 타진하였다. Sn-37%Pb 솔도 합금의 Pbdldhs 용출농도는 국제규제치인 3ppm보다 훨씬 적은 0.46ppm이었고, 환경문제를 유발하지 않는 것으로 확인되었다. 이 합금계의 융점은 $183-192^{\circ}C$이고, 응고온도범위도 $5^{\circ}C$내외로 매우 좁았다. 젖음성은 In의 첨가양에 따라 큰 차이가 거의 없었으며, Sn-375Pb와 비슷하였다. 융점 및 젖음성 측면에서 Sn-37%Pb와 대체 가능한 것으로 판단되었다. 경도는 Sn-37%Pb의 약 1.5배이고, 인장강도는 Sn-37%Pb의 것보다 높고, In의 첨가량에 따라 증가하였지만, 연신율은 감소하였다. In이 1% 첨가된 합금에서는 수지 상정 경계에 Ag3Sn과 Pb가 정출되고, 3% 이상에서는 $Ag_3Sn$과 $Ag_3In$ 및 Pb가 정출되었다. 드로스 생성속도는 Sn-37%Pb 합금이 Sn-5%Pb-1.5%Ag 합금보다 빠르고, In을 첨가할수록 느리고 2%의 In을 첨가한 합금은 180분에서도 거의 드로스가 발생하지 않았다. This work designed Sn-5%Pb-1.5%Ag-x%In solder alloy to develop the solder alloy with low Pb content. This solder alloy doesn't cause environmental pollution. and this study reviewed the probability of replacement of Sn-37%Pb solder as evaluation of melting range, wettability. microstructure, microhardne'ss, tensile strength, drossability of this new solder alloys. The level of international regulation in dissolution amount of Pb ion was 3ppm. But dissolution amount of Pb ion in Sn-5%Pb solder alloy confirmed not to threat the global environmental is 0.46ppm. The melting range of this solder alloy was $183-192^{\circ}C$. Also the range of solidification was very narrow within $5^{\circ}C$. The wettability was similar to Sn-37%Pb solder, and the effect of amount of In addition of wettability couldn't be founded. The probability of replacement in the melting range and wettability is very high. And microhardness of this solder alloy was 1.5 times of conventional type solder. Tensile strength of new solder alloys was a little high than that of conventional type solder. With increasing amount of In% addition, tensile strength was increased, but elongation was decreased. The solder alloy of l%In addition revealed AgSn and Pb on dendrite microstructure boundary, and $Ag_3Sn$, $Ag_3In$ and Pb were revealed on it at the solder alloy of 3% In addition. The drossability was superior to Sn-37%Pb solder alloy and the solder alloys of 2% In addition was not generated for 3hrs.

두산중공업 R&D 현황 및 기업 소개

이태호,안민용,주철홍 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12

보일러 기동정지 운전중의 열응력 시뮬레이션

이지문(Ji-Moon Lee),주철홍(Cheol-Hong Joo) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11

Boiler components of fossil power plant are operated under the severe stresses resulted from high temperature and high pressure during startup and shutdown. While steam temperatures through components abruptly change from low temperature and high temperature, thermal stresses reach the design limit at the same time and reduce the remaining life of components. In general, these stresses are calculated with the commercial programs such as ANSYS and ABACUS. But these calculations are time-consuming and expensive. This paper says that simple and quick simulation during boiler startup and shutdown is developed with Green's Function and the optimum curve is calculated with this program. Green's function is the thermal stress by the unit change of steam temperature. This method is useful of the thermal stress simulation at the startup/shutdown.

발전소용 12Cr-Mo-V강의 재현용접 열영향부에 대한 크리프 손상 평가

정용근,강용호,박종진,주철홍,박익민 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.1

The creep rupture tests were carried out on actual welded joint specimens of 12Cr-Mo-V steel. It was revealed that the creep rupture life of actual welded joint was approximately 41% of that of base metal and the creep damage of it occurred mainly at intercritical heat-affected zone(HAZ). On the basis of the heat input during the welding, microstructure, microhardness and grain size of the actual intercritical HAZ, simulated HAZ was made in order to evaluate its material properties. The tensile tests and interrupted creep test were carried out on the simulated HAZ specimens. It was found that the tensile properties of the simulated HAZ were slightly inferior to those of the base metal and the creep rupture strength of it was approximately 46% of that of base metal and the creep strain rate of it was higher than that of base metal. The creep cavities in simulated HAZ were found at an early stage of creep life and the number of creep cavities increased exponentially and the average diameter of cavities increased linearly with creep life fraction. Plasticity constants of simulated HAZ can be available for the analysis of creep crack growth and the number and average diameter of creep cavities can be available for the evaluation of creep damage for welded joint.

보일러 압력부 실시간 열응력 모니터링을 통한 피로 및 크립 수명평가

이지문(Ji-Moon Lee),김형규(Hyeung-Gue Kim),정재진(Jae-Jin Jung),주철홍(Cheol-Hong Joo) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.11

The components of fossil power plants are operated under frequent change of high temperature and high pressure. In order to diagnose and evaluate the safety and integrity of power plant components, Thermal stress monitoring is required with real-timely measuring the operation data such as temperature and pressure. Fatigue damage is caused from the thermal stress during the start-up and shutdown of power plant. Creep damage comes from the high-temperature condition for a long time. The precise evaluation of these damages is necessary for escaping the plant outage and rescheduling the plant inspection. We developed that the thermal stress monitoring system operates on personal computers and local area network under the client/server environment. This system is able to collect the data (temperature and pressure) from boiler control system as well as from the sensors. Sensors are installed at the high-risk parts and at the components with cracks detected by NDE. Thermal stresses, due to the rapid change of fluid temperature, are calculated with using Green's function method. Calculation results are stored in the database of SQL Server 7.0. This paper says that the damage evaluation with real-timely monitoring thermal stresses gives utility operators benefits such as determining the inspection schedule, changing inspection interval, and replacing risk components on the basis of operation history.