• 한국공작기계학회논문집
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• 제14권1호
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• pp.52-57
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• 2005

In the foe of global competition, the requirements for the continuously increasing productivity, flexibility and quality(dimensional accuracy, mechanical properties and surface properties) have imposed a mai or change on steel manufacturing industries. Indeed, one of the keys to achieve this goal is the automation of the steel-making process using AI(Artificial Intelligence) techniques. The automation of hot rolling process requires the developments of several mathematical models for simulation and quantitative description of the industrial operations involved. In this paper, an on-line training neural network for both long-term teaming and short-term teaming was developed in order to improve the prediction of rolling force in hot rolling mill. This analysis shows that the predicted rolling force is very closed to the actual rolling force, and the thickness error of the strip is considerably reduced.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.124-129
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• 2003

In the face of global competitor the requirements flor the continuously increasing productivity, flexibility and quality(dimensional accuracy, mechanical properties and surface properties) have imposed a major change on steel manufacturing industries. Indeed, one of the keys to achieve this goal is the automation of the steel-making process using AI(Artificial Intelligence) techniques. The automation of hot rolling process requires the developments of several mathematical models fir simulation and quantitative description of the industrial operations involved. In this paper, a on-line training neural network for both long-term teaming and short-term teaming was developed in order to improve the prediction of rolling force in hot rolling mill. This analysis shows that the predicted rolling force is very closed to the actual rolling force, and the thickness error of the strip is considerably reduced.

• 한국재료학회지
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• 제4권2호
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• pp.241-249
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• 1994

항공기용 고력 AI합금인 7075 AI합금의 물성개선을 위한 가공열처리 방안으로서 과시효처리후 온간 및 냉간 압연에 의한 소성가공이 재결정조직과 강도에 미치는 영향에 대하여 연구하였다. 소송가공후 재결정처리에 의해 결정립을 미세화하는 공정에서 소성가공 전 과시효를 함으로써 재결정립의 미세화 정도는 더욱 현저하였다. 이는 과시효에 의한 조대한 석출물이 재결정처리시 핵생성 site로서 작용하였음을 의미한다. 본 연구에서 항복강도와 재결정립의 크기와는 Hall-petch식을 만족하지 않았으며 이는 등축이 아닌 연신된 결정조직에 기인된 결과로 보이며, 항복강도가 재결정립의 종횡비에 직선적으로 비례하였다. 또한 결정립 미세화를 통한 강도, 인성향상을 목적으로 하는 TMT(Thermo mechanical Treatment)공정에서는 심한 냉간가공에 의해서보다는 온간에서의 소성가공이 바람직함을 알 수 있었다.

• 한국분말재료학회지
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• 제10권1호
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• pp.15-20
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• 2003

Hybrid $A1_2O_3-TiC$ ceramic particle reinforced 6061 and 5083 Al composite powders were prepared by the combination of twin rolling and stone mill crushing process, followed by consolidating processes of cold compaction, degassing and hot extrusion. The composite bar consists of lamellar structure of ceramic particle rich area and matrix area, in which the hybrid was decomposed into each TiC of about $3-4\mutextrm{m}$ and $AI_2O_3$ particles of about $1-2\mutextrm{m}$ in diameter. It also found that fine $Mg_2Si$ precipitates of about 30 nm were embedded in the matrix, which have grains of about 3 $\mutextrm{m}$. Higher UTS was measured at the 5083 composite bar compared to the conventionally fabricated composite, due to again refinement effect by the rapid solidification. No particle was shown to form in the interface between the matrix and reinforcement, whereas carbon was diffused into the matrix.