http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
김기철,차준호,Kim Ki Chol,Cha Joon Ho 한국재료학회 2004 한국재료학회지 Vol.14 No.1
Laser weldability of aluminized steels for deep drawing application has been investigated. Test coupons for Nd:YAG laser welding and $CO_2$ laser welding were prepared trom the commercial steels. According to the test results, total penetration and back bead width of aluminized steels were sensitive to the welding conditions. Bead width at the half thickness of the overlap joint, however, was rather constant. Laser weldability of aluminized steels was superior to that of zinc coated steel. Weld microstructure revealed that overlap zone adjacent to the fusion line was filled with coated materials, which was thought to be desirable to protect weld from crevice corrosion. The aluminum coated materials was also found in the weld metal. Practically no spattering was observed in the laser welding of aluminized steels even when the welding was performed without joint gap. In the welding of zinc coated steel, however, spattering was so severe that it was difficult to get the acceptable weld. Bead quality of aluminized steel laser weld was smooth and stable.
김태경(Kim Tae-kyung),김기철(Kim Ki-chol) 동아대학교 해양자원연구소 2003 동아대학교 해양자원연구소 연구논문집 Vol.15 No.-
Busan port has been developed as the main hub port in the eastern asia. As the ship transportations increase, the risk of maritime accidents also increase. Maritime accidents result in marine pollutions such as oil or toxic material spill problems. As pollutant materials spread mainly in the direction of water movement, it is desirable to construct the real time prediction system of ocean circulation in the harbor as the effective strategy to minimize the pollution.<BR> In this study, the system to predict the depth-integrated currents forced by tide and wind at Busan port is developed using G.U.I. system.
계장화 충격시험에 의한 구상흑연 주철의 동적파괴인성의 고찰
윤의박,김기철,고광필 ( Eui Park Yoon,Ki Chol Kim,Kwang Pill Ko ) 한국주조공학회 1989 한국주조공학회지 Vol.9 No.2
N/A Microstructures and fracture toughness of the weld heat-affected zone of the ductile cast iron have been investigated. With increasing the cooling time from 800℃ to 500℃, the matrix structure of the heat-affected zone was transformed to martensite, martensitet pearlite, pearlite and pearlite including small amount of ferrite. The use of a proper preheat temperatures prevented the formation of martensite. These welding conditions corresponded to the preheat temperature of 200℃, heat input of 30KJ/㎝. And the instrumented charpy impact test has been carried out on a welded ductile cast iron. Result showed that the dynamic fracture toughness, K_(Id) was increased slightly with preheat temperature and heat input. In this work, it was shown that apparent impact energy includes contributions other than that of the true deflection of specimen. We found that a compliance energy correction was always needed to determine the true specimen energy. For this purpose, elastic compliance value of testing machine was measured dynamically by the low blow test to correct the apparent impact energy. From these results, the true specimen energy was nearly 62 percent of an apparent impact energy value. There, in instrumented impact testing, machine compliance corrections must be adapted to load-deflection curve.
Nd:YAG 레이저를 이용한 알루미늄도금강판의 용접성(II) - 용접부내 알루미늄의 거동 -
김종도,이정한,김기철,Kim, Jong-Do,Lee, Jung-Han,Kim, Ki-Chol 대한용접접합학회 2007 대한용접·접합학회지 Vol.25 No.4
Aluminized steel sheet is a material with excellent heat resistance, thermal reflection and corrosion resistance. It has wide applications, owing to its low cost and excellent performance, in the petrochemical industry, electric power and other energy conversion systems, etc and has attracted the attention of many investigators. But the welding of aluminized steel sheet has a problem of decreasing tensile-shear strength, caused by mixed Al in the weld. This study investigated behavior of Al and its structural properties to resolve this problem. Several analysis equipment(SEM, EDX, EPMA) were used to investigate Al element in the weld. Also microhardness tester and TEM equipment were used to find the intermetallic compound. As a result of this study, Al-rich zones existed in the weld and Fe-Al intermetallic compounds were found in these zones. At the same time, the weldability of aluminized stainless steel sheet was investigated and compared with that of aluminized steel sheet. Although there is a difference between the base metal of the low carbon steel and stainless steel, it is interpreted that a behavior of Al element in the weld is similar.
저탄소강의 알루미늄코팅조건에 따른 Nd:YAG 레이저 용접특성
김종도(Jong-Do Kim),이정한(Jung-Han Lee),김숙환(Sook-Hwan Kim),김기철(Ki-Chol Kim) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
Aluminized steel sheet that Al coated on low carbon steel has a excellent heat resistance, thermal reflection and corrosion resistance. It has applied to fuel tank, automotive exhaust systems, etc. Laser weldability of the aluminized steel for the full penetration welding will be described in this paper. We focused on the effect of Al coating conditions on weld strength. For these objectives, aluminized steel sheets that has various thickness and coating weight were prepared for laser welding. And then, tensile-shear and hardness test were carried out. At that same time, Al content mixed in weld after laser welding was evaluated and investigated a correlation between the mixed Al and mechanical properties. Besides, as removing partially coating layer, weldability has been investigated according to position of coating layer. As a result of this study, as increasing Al content in weld, tensile-shear strength was decreased. Also it was identified that Al of coating layer caused grain growth.