• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1996년도 춘계학술대회논문
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• pp.165-171
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• 1996

Recently, to improve the productivity in the continuous casting process, thin slab continuous caster which is one of the new steelmaking technologies by a high speed casting has been introduced. In the process of the thin slab continuous cast, there is more possibility than convnetional one that the deformation be occurred by the bulging of solidified shell, since the thickness of soliidfied shell is very thin as much as 60mm after the casting is finished. In some cases of severe bulging, there might be more breakout. In this paper, using finite difference method , solification analysis of slab is made as well as the thicknessof solidified shell and temperature are calculated. Also, based on the data of the calculated temperature, the deformed behavior of solidified narrow face is anlayzed with the MARC which is a package program for finite element analysis.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 추계학술대회 논문집
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• pp.181-185
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• 2001

Three-dimensional finite-element-based numerical model of turbulent flow, heat transfer, macroscopic solidification and inclusion trajectory in a continuos steel slab caster was developed Turbulence was incorporated using the Improved Low-Re turbulence model with positive preserving approach. The mushy region was modeled as the porous media with average effective viscosity. A series of simulations was carried out to investigate the effects of the casting speed, the slab size, the delivered superheat the immersion depth of the SEN on the transport phenomena. In the absence of any known experimental data related to velocity profiles, the numerical predictions of the solidified profile on a caster was compared with breakouts data and a good agreement was found.

• 전력전자학회논문지
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• 제8권4호
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• pp.321-327
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• 2003

연속주조 프로세스는 고온의 액체 용강을 고체 금속으로 만드는 프로세스로서, 스트랜드 구동롤의 역할은 운전자가 설정한 주조 속도 제어 패턴에 따라 정확하게 주편을 인발하는 것이다. 기존의 스트랜드 구동롤의 제어는 주조 속도만을 제어하였으나 전동기 드라이버 세팅의 부정확성 및 변동, 연속적인 주조에 의한 구동롤의 마모 및 변형에 의한 롤 직경의 변경, 주조 중 주편 벌징량의 변동 등의 요인에 의해 주조 중 주편을 인발하는 데 소요되는 전체 인발력이 각 구동롤에 적절하게 분배되지 않아 주편 코너부에 수평 크랙을 발생시켜 주조 속도를 증가하는데 있어서 결정적인 장애요인이었다. 본 논문에서는 스트랜드 구동롤에 인가되는 인발력 분포와 주편 품질과의 상관 관계를 도출하고 주조 중에 연속적으로 인발력을 분배할 수 있는 알고리즘을 제안하였다. 제안한 인발력 분배 알고리즘은 각 구동롤 전동기의 절대적인 토크를 제어하는 것이 아니라, 상위제어기에서 결정한 인발력 분배 비율에 따라 각 구동롤 전동기의 토크분 전류를 상호 비교하여 속도 설정치를 조정함으로써 이루어진다. 그리고 인발력 분배 알고리즘의 동작 확인을 위해 광양제척소 1연주공장 4연주기에 적용하여 양호한 결과를 확인하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 추계학술대회 논문집
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• pp.264-267
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• 2001

by three-dimensional finite element method. The guide roll is an intermediately supported trans-axle miler, so called I-STAR roll, which was designed by VAI. The guide roll has been used in POSCO since 1998. Though the number of stowage in casting has been apparently decreased since thef it has occasionally been failed during operation. The simulations were carried out to find out the status of stress and deformation as well as improvement of the guide roll. The thermal effect is much more dominant than ferro-static pressure or others in stress and deformation of the guide roll. The material of the guide roll is SCM440.

• 조명전기설비학회논문지
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• 제18권3호
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• pp.74-80
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• 2004

연속 주조 공정에서 설정한 속도로 주편을 인발하는 스트랜드 구동롤에 인발력이 적절하게 분배가 되지 않으면 주형 레벨의 주기적인 변동을 유발시킴과 동시에 주편의 품질을 저하하게 된다. 따라서 본 논문에서는 주편의 속도를 제어함과 동시에 각 구동롤에 운전자가 원하는 비율로 인발력을 분배할 수 있는 알고리즘을 제안한다. 제안된 방법은 전동기에 작용하는 토크 전류를 상위 제어기로 귀환하여 평균 토크 전류를 산출하고 각 구동롤 전동기의 토크 전류와 비교하여 전동기의 속도 기준값을 미소하게 변경함으로써 각 구동롤 전동기의 토크 전류가 평균 토크 전류에 추종하도록 하여 인발력을 분배한다. 그리고 과도상태 개선을 위하여 안티와인더업(anti-wind up) 제어기를 가진 인발력 제어기를 적용하였으며, 제안된 알고리즘의 확인을 위하여 포스코의 시험연주기에 적용하여 우수성을 입증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.715-718
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• 2002

As the modern technology of continuous casting plant is focused on improvement of slab quality, the control system of strand driven roll which has positive effect is investigated in this paper. An irregular distribution of withdrawal force gives rise to horizontal crack in high and middle grade carbon steel. Based on the basic understanding on design concept of high technology company, monitoring the withdrawal force distribution of strand driven roll and analysis of the control system was Performed at continuous casters of POSCO. The control algorithm of withdrawal force distribution for A.C motor vector control, which was derived from above study and had been applied for POSCO Kwangyang 1-4 continuous casting plant, is presented.

• 대한산업공학회지
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• 제24권4호
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• pp.649-660
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• 1998

Steel making in Mini Mill consists of three major processing stages: molten steel making in an electric arc fuenace, slab casting in a continuous caster, and hot rolling in a finishing mill. Each processing stage has its own lot grouping criterion. However, these criteria in three stages are conflicting with each other. Therefore, delveloping on efficient lot grouping algorithm to enhance the overall productivity of the Mini Mill is an extremely difficult task. The algorithm proposed in this paper is divided into three steps hierarchically: change grouping, cast grouping, and roll grouping. An efficient charge grouping heuristic is developed by exploiting the characteristics of the orders, the processing constraints and the requirements for the downstream stages. In order to maximaize the productivity of the continuous casters, each cast must contain as many charges as possible. Based on the constraint satisfaction problem technique, an efficient cast grouping heuristic is developed. Each roll consists of two casts satisfying the constraints for rolling. The roll grouping problem is formulated as a weighted non-bipartite matching problem, and an optimal roll grouping algorithm is developed. The proposed algorithm is programmed with C language and tested on a SUN Workstation with real data obtained from the H steel works. Through the computational experiment, the algorithm is verified to yield quite satisfactory solutions within a few minutes.