• 한국식품저장유통학회지
• /
• 제6권3호
• /
• pp.313-318
• /
• 1999

쌀을 수분함량 24%로 10시간 동안 조질한 후 roll mill로 1회 분쇄한 후 pin mill로 1회 분쇄하였을 때 의 특성을 조사하였다. 소요전력은 다른 제분방법(TRMR, WDRMR, DPMR) 보다 가장 적었다. 쌀가루의 수분함량은 수침하여 제분한 쌀가루의 32.8%, 조질하여 제분한 쌀가루의 22.3%보다 훨씬 적은 17.2%였다. 쌀가루의 입도는 100 mesh 이상의 입자가 87.4%로 수침 roll mill 쌀가루 6.8%와 조질 roll mill 쌀가루 7.7%보다는 훨씬 높았고 건식 pin mill 쌀가 루의 80%보다도 높았다. 전자현미경으로 본 쌀가루의 입자구조를 살펴본 결과 수침한 쌀과 조질한 쌀의 분쇄된 쌀가루 입자 한 개는 수많은 작은 입자들이 모여 덩어리 모양의 입단(粒團, group)을 형성하고 있었다. 호화 개시온도는 63.2$^{\circ}C$로 다른 방법으로 제분한 쌀가루보다 1.3$^{\circ}C$ 낮았다. 최고점도, 최저점도, 냉각시 5$0^{\circ}C$에서의 점도도 다른 방법으로 제분한 쌀가루보다 낮았다. 이 방법으로 쌀을 제분하면 밀가루와 같이 고우며 백도가 높고 품질이 좋은 쌀가루 제품을 얻을 수 있었다.

• 한국식품영양과학회지
• /
• 제43권11호
• /
• pp.1742-1748
• /
• 2014

본 연구는 시판용 쌀가루와 제분공정을 달리한 쌀가루들의 품질 특성을 비교한 후 설기떡 제조에 적합한 쌀가루 가공공정을 제안하고자 하였다. 입도분포는 1st roll로 제분한 후 건조하였을 때 $710{\mu}m$ 초과의 쌀가루만을 건식제분기인 pin mill에 적용한 roll & pin에서 $250{\mu}m$ 이하의 작은 입도가 약 48%를 차지하여 CRF(2nd step roll mill)에 비해 높은 비율을 나타내었다. 일반성분은 1단계의 제분만을 거친 1st roll에서 단백질, 지방, 회분 함량이 높았고, CRF와 roll & pin은 유의적으로 낮은 값을 나타내었다. 색도는 작은 입자의 분포 비율이 많은 roll & pin에서 L값이 높았으며, 손상전분, 물결합력은 CRF와 roll & pin이 유의적으로 높게 나타났다. RVA 호화특성은 CRF와 roll & pin의 호화개시온도, 최고점도 및 노화 정도를 반영하는 setback 값 또한 1st roll에 비해 낮았다. 또한 위 3가지의 쌀가루(CRF, 1st roll, roll & pin)를 이용하여 제조한 설기떡의 외관 관찰에서 CRF와 roll & pin의 경우 큰 차이를 나타내지 않았으나 1st roll의 경우 거친 내상 및 외상을 확인할 수 있었다. 조직감에서는 roll & pin으로 제조한 쌀가루의 설기떡과 CRF로 제조한 설기떡은 유사한 것으로 나타났다. 정량적 묘사분석 결과 외관, 향, 맛, 질감 및 전반적 기호도에서 roll & pin이 CRF나 1st roll에 비해 높은 값을 나타내었다. 따라서 설기떡의 제조 시 건식제분인 roll & pin으로 제조한 쌀가루가 현재 상용화되어 있는 습식제분법인 2 step roll mill보다 제분공정을 간편화한 우수한 설기떡을 제조할 수 있으리라 사료된다.

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

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2008년도 추계학술대회 논문집
• /
• pp.95-98
• /
• 2008

In the present work, cross-roil rolling was rallied out using a rolling mill in which the roll axes are tilted by $5^{\circ},\;7.5^{\circ},\;10^{\circ}$ towards the transverse direction of the roiled sample. The evolution of strain states during cross-roll rolling was investigated by three-dimensional finite element method (FEM) simulation. Parallel to cross-roll rolling, normal-rolling using a conventional rolling mill was also carried out in the same rolling condition for clarifying the effect of cross-roll rolling. It turned out that three shear rate components were all introduced to the rolled sample by the cross-roll rolling process, while only one shear rate component operated during normal-rolling.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2008년도 춘계학술대회 논문집
• /
• pp.404-407
• /
• 2008

In the present work, cross-roll rolling was carried out using a rolling mill in which the roll axis is tilted by $7.5^{\circ}$ towards the transverse direction of the rolled sample. The evolution of strain states during cross-roll rolling was investigated by three-dimensional finite element method (FEM) simulation. Parallel to cross-roll rolling, normal-rolling using a conventional rolling mill was also carried out in the same rolling condition for clarifying the effect of cross-roll rolling. It turned out that three shear rate components were all introduced to the rolled sample by the cross-roll rolling process, while only one shear rate component operated during normal-rolling.

• 한국기계가공학회지
• /
• 제16권4호
• /
• pp.38-45
• /
• 2017

A finite element analysis-based approach which investigates the causes of the breakdown in the outer ring of the choke at hot rod rolling mill is presented. Two-dimensional drawings of the whole vertical-type mill stand are transformed into three-dimensional CAD models. Non-linear elasto-plastic deformation analysis of material at the roll gap is performed for computing roll force and torque of the work roll. Then, the reaction forces of the bearing rings together with a set of roller bearings that support the work roll are obtained by means of rigid body motion analysis. Finally, stress behaviors in the bearing rings together with a set of roller bearings that support the work roll are investigated by linear elastic analysis. Results reveal that stress at the contact area between the outer ring and roller bearing is extraordinary high when an internal gap between an external surface of the outer ring and the internal surface of the chock due to wear of the inside of the chock occurs.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
• /
• pp.180-180
• /
• 2000

The shape of cold strip for the stainless process has been become issue in quality recently, and hence POSCO (Pohang Iron & Steel Co., Ltd) developed an automatic control system for strip shape in the sendzimir mill. The strip shape is measured by an outward measuring roll and is controlled by As_U roll and first intermediate roll. As_U roll consists of 8 saddles, which are controlled vertically. The fist intermediate rolls, which are controlled horizontally, consist of two pairs of rolls up and down. A developed shape control system is applied to real plant by using fuzzy logic and neural network method to control actuators; As_U roll and first intermediate roll. This system composes mainly of three parts as a real-time system, input to output conditioner board, and man-machine interface. The actual shape is recognized by neural network and converted into symmetric shape. The fuzzy controller, based on the shape from neural network and sensor, controls positions of the As_U roll and first intermediate roll. This paper verifies the shape controller performance. The experiments are made on line for the sendzimir mill. The shape control performance shows very efficient for the target tracking, shape symmetry, and fluctuation of shape.

• 대한금속재료학회지
• /
• 제48권7호
• /
• pp.644-650
• /
• 2010

Interstitial free (IF) steel sheets were cold rolled by the cross-roll rolling mill in which the roll axes are tilted by ${\pm}7.5^{\circ}$ away from the transverse direction of the rolled sample. After cross-roll rolling of IF steel sheets, the cold rolling and the recrystallization textures were distinguished from those observed after rolling in a normal rolling mill. The three-dimensional finite element method (FEM) simulation revealed that the operation of a large shear strain ${\varepsilon}_{23}$ during cross-roll rolling leads to the formation of a distinct cold rolling texture. During recrystallization annealing, a pronounced change in texture components was not observed, which is attributed to the lack of either selective growth or oriented nucleation during the recrystallization process. Cold cross-roll rolling led to the formation of finer recrystallized grains in IF steel sheets.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
• /
• pp.163-171
• /
• 1999

The abnormal grain coarsening in wire rolling induces detrimental defects, such as jagged size tolorance, severe bending after heat treatments and drawing troubles, in the following secondary processes. Neishi et al observed that there is a band type region where grain coarsenting occurs in the plastic strain vs. deformation temperature plot. Based on the finding, we have investigate whether grain sizes and ferrite volume fractions are correlation to deformation strain with three kinds of wire rod diameters as for the different average deformation conditions. The samples were chosen from the No.2 Wire Rod Mill of POSCO where 3-roll type of finishing mill stand are used. It was found in the present work that the grain size and ferrite volume fraction of the rolled and cooled microstructure were changed with rolling reduction and rolling temperature. Abnormally grown grains at various observed points were also found. To have homogeneously fine grains of microstructure from the No. 2 Wire Rod Mill, it will be easier to control finish rolling temperature at around 750$^{\circ}C$ rather than to find another rolling schedule.

• 한국소음진동공학회논문집
• /
• 제21권3호
• /
• pp.199-205
• /
• 2011

This paper proposes a framework to predict the mechanical fault of hot rolling mill system (HRMS). The optimum process of HRMS is usually identified by the rotating velocity of working roll. Therefore, observing the velocity of working roll is relevant to early know the HRMS condition. In this paper, we propose the framework which consists of two methods namely spectrum matrix which related to case-based fast Fourier transform(FFT) analysis, and three dimensional condition monitoring based on novel visualization. Validation of the proposed method has been conducted using vibration data acquired from HRMS by accelerometer sensors. The acquired data was also tested by developed software referred as hot rolling mill facility analysis module. The result is plausible and promising, and the developed software will be enhanced to be capable in prediction of remaining useful life of HRMS.