http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
김지준,최정길,홍준표 ( Ji Joon Kim,Jeong Kil Choi,Chun Pyo Hong ) 한국주조공학회 1995 한국주조공학회지 Vol.15 No.1
N/A Prediction of shrinkage cavity in shaped castings considering solidification contraction has been considered to be one of the most important subjects in casting design. Several methods of prediction of the position and shape of shrinkage cavity in castings by computer simulation have been reported. However, most of them did not fully consider solidification contraction. Casting defects caused by volume contraction during solidification of molten metal are categorized into shrinkage cavity and porosity, depending on their generation mechanism. This paper describes in detail a method for predicting the shape and position of shrinkage cavities and porosities in shaped castings both for pure metals and alloys. A computer program was developed to calculate the shape and dimension of shrinkage cavities in shaped castings. The potential of the present method has been successfully demonstrated by comparing predicted cavity shapes with those obtained in a series of experimental castings.
주강품 압탕 설계에 체적 수축을 고려한 응고해석의 적용
김지준,김기영,최정길,홍준표 ( Ji Joon Kim,Ki Young Kim,Jeong Kil Choi,Chun Pyo Hong ) 한국주조공학회 1995 한국주조공학회지 Vol.15 No.5
N/A Test castings in plate, disc, and cubic shaped castings for 0.2wt.% carbon and stainless steel have been poured to examine the effects of the riser dimensions including riser neck on the casting soundness. Three empirical methods were chosen in risering of steel castings. A computer program of solidification analysis considering liquid and solidification contraction was developed to apply for riser-design calculated by using their methods in plate, disc, and cubic shaped castings, and to calculate the position and dimension of shrinkage cavity in complex shaped casting. The potential of present method has been successfully demonstrated by comparing predicted cavity shapes with those obtained in a series of experimental castings. Three empirical methods can be used in a practical way to make a rapid estimation of tie minimum riser diameter, but they can not provide a criterion of casting soundness with shape and material on all occasions. The shape and position of shrinkage cavity can be successfully predicted both using the present method and using risering calculated by their methods regardless of the shape and cast material.
김지준,김진수,류관호,최정길,이진형,홍준표 ( Ji Joon Kim,Jin Soo Kim,Gwan Ho Ryu,Jeong Kil Choi,Zin Hyoung Lee,Chun Pyo Hong ) 한국주조공학회 1993 한국주조공학회지 Vol.13 No.3
N/A In gravity die casting, die cooling systems are frequently employed with water cooling to remove the heat of the solidifying metal. Thermal modeling is an important technique in mold design for improving the productivity of the process. Computer simulation system which consists of pre-processor, main solidification simulator and post-processor has been developed for three dimensional solidification analysis of cyclic gravity die casting. The pre-processor is used for mesh generation in a PC system. The modified finite difference method is adopted for the main solidification simulation algorithm during all the casting cycles. The post-processor graphically presents the simulation results. Several experiments in automotive cast piston were carried out. The temperature variations in casting and mold with time are measured experimentally, and the results are compared with calculation results. The effects of cycle number on solidification pattern are also studied. Several experimental results for the prediction of shrinkage defects are compared with calculated results.
상향식 연속 주조법에 의한 결정 성장에 있어서의 열, 운동량 및 물질전달에 관한 수치 해석
홍준표,김지준 대한금속재료학회(대한금속학회) 1993 대한금속·재료학회지 Vol.31 No.7
Transport phenomena in the UCC process are important in that they effect the quality of the crystal. Hence the heat, fluid flow and mass transfer must be considered in order to understand crystal growth. A numerical model has been developed for the prediction of temperature, velocity, and concentration fields. The governing equations have been discretized using the control-volume based on the finite difference method. The effects of convection on the solute profiles both in the melt and in the crystal have been studied. Attention is also focused both on the initial transient stage of solte redistribtuion and on the radial inhomogeneity of the solute concentration in the grown crystal. The effects of process variables, such as mold length, crucible wall temperature, and crystal pulling speed upon transport phenomena have been investigated.
상향식 연속주조법에 의한 Plate 및 Tube 형 Sn 결정의 성장 안정성
홍준표,진현진,김지준 대한금속재료학회(대한금속학회) 1993 대한금속·재료학회지 Vol.31 No.2
The Upward Continuous Casting process which manufactures near-net shaped crystals directly from the melt has been improved in order to reduce the cost of products. Growth of plate and tube shaped crystals using the U.C.C. process was carried out with tin. Near-net shaped tin plates and tubes have been produced with the newly developed mold. The effects of process parameters on the size and the shape of the crystal were studied:these were the meniscus height(S), the length between the top surface of the mold and free surface(H), the mold temperature, and the pulling speed. Of these S and H were the most important parameters in determining the crystal shape stability. The U.C.C. process was compared with other shaped growth methods to determine its growth stability. It can be concluded that the U.C.C. process will find applications in the growth of various shaped crystals.