• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.813-814
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• 2008

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.105-108
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• 2003

Sheets of aluminum alloy 1100 were asymmetrically cold rolled in a rolling mill with different roll speeds. In order to promote the shear deformation during asymmetrical rolling, cold rolling without lubrication was performed. The evolution of texture components during asymmetrical rolling was investigated by the calculation of the orientation distribution function (ODF) using the monoclinic sample symmetry. The strain state during asymmetrical rolling was tackled by means of FEM calculations. Asymmetrical rolling gave rise to the development of pronounced strain gradients throughout the thickness layers which resulted in the formation of strong texture gradients in the aluminum sheet.

• Transactions of Materials Processing
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• v.12 no.3
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• pp.244-250
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• 2003

Sheets of aluminum alloy 1100 were asymmetrically cold rolled in a rolling mill with different roll speeds. In order to promote the shear deformation during asymmetrical rolling, cold rolling without lubrication was performed with a roll speed ratio of 1.5/l.0. The evolution of texture components during asymmetrical rolling was investigated by the calculation of the orientation distribution function (ODF) using the monoclinic sample symmetry. The strain state during asymmetrical rolling was tackled by means of FEM calculations. Asymmetrical rolling gave rise to the development of pronounced strain gradients throughout the thickness layers which resulted in the formation of strong texture gradients in the aluminum sheet.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.7
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• pp.2257-2265
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• 1996

In the cold rolling mill, it is very important that a constrained static flow stress of rolled strip and rolling force calculation model be exactly considered to improve an prediction accuracy for rolling forces. Therefore, in this study, the values of the constrained static flow stress are used by deriving the regression equation which is a function of rolling conditions(FDT, CT) and chemical compositions(C, Si, Mn), previously applied by making the tables of yield strength for hot coils with size. And with the consideration that an elastic deformation part of an rolled strip appears at the entry and delivery side of the contacting area between the work roll and rolled strip is calculated. By applying these methods, the more accurate prediction for rolling force is obtained. As a results, the deviation of thickness is significantly reduced in the rolling direction.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.4
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• pp.895-905
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• 1999

This paper identifies a linear time-invariant mathematical model of each stand of a five-stand tandem cold mill to design a robust $H_\infty$ thickness controller by applying input and output data sets to N4SID (Numerical algorithms for Subspace State Space System Identification) method. The input-output data sets describe interstand interference in the process of tandem cold rolling and are obtained from a nonlinear simulator of the tandem cold mill. In result, it is shown that the identified model well approximates the nonlinear model than a Taylor linearized model. Furthermore, uncertainties including roll eccentricity and incoming strip variation are quantitatively analyzed from the plot of maximum singular values.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.7
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• pp.167-175
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• 1996

Work roll wear in the cold rolling of steel strip is strongly affected by rolling materials, rolling conditions and lubrication. Tests were performed to find the effects of rolling materials under the same lubricating conditions. Surface roughness of cold rolled steel strip as well as the coating technique itself is quite improtant in obtaining high image clarity of electronic products and car outer panels. Therefore this paper reviews for improvement of roughness and peak count about the surface of Cr coated work roll is investigated from the actual temper mill. The conclusions were obtained as follows; 1) Work roll wear in the cold rolling of steel strip is strongly affected by carbon contents of rolling materials, but there is not a separating force and total reduction ratio. 2) The roughness of strip surface is larger in the direction of width than in roll direction. 3) The electro-discharge textured roll has more uniform roughness distribu- tion than shot blasted roll and it's life time is two times longer than shot blasted because it has more harmonic wave roughness, and the higher peak count of surface roughness. 4) The life time of Cr coated work roll is 2 times longer than that of shot blasted work roll and variation of peak count, roughness and life time of Cr coated work roll is similar to electro-discharge texturing work roll. 5) The proper Cr coating thickness is 10 .mu. m at the work roll of temper mill.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.5
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• pp.1149-1157
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• 1995

The research for variation of coolant film thickness and separating force has been investigated following the examination for friction profile of work roll and roughness change of strip surface in rolling mill producting actual commercial products. The obtained results are as follows ; (1) Coolant film thickness in cold rolling has been increased relative to the circumferential velocity of work roll, and formation of coolant films has decreased with the smaller diameter of work roll. (2) Separating force is related to the formation of coolant film, and large separating force is needed to the formation of coolant film but it is constant after formation of appropriate film. (3) Wear and roughness alleviation of work roll is larger in bottom-roll than in top-roll on cold surface is larger in the direction of width than in roll direction, and changes of roughness and strip surface hardness rarely occurred after 3 passes.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.4
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• pp.429-435
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• 2012

An abrasion due to continuous friction between a work roll and strip causes the mass of the work roll to be unbalanced in the rolling process. We developed a mathematical model for the rolling mill considering the unbalanced mass and verified the model experimentally. The work roll was approximated as a rigid rotor with eccentricity, and the effect of the unbalanced mass on chatter vibration was investigated. The joint forces computed by quasistatic analysis were applied to the work roll in the rolling mill. Transient responses were obtained, and frequency analysis was performed by solving equations of motion using a direct integration method. Horizontal vibrations were more strongly affected by eccentricity than vertical vibrations. In the horizontal direction, a small eccentricity of 1% of the work roll radius considerably increased the amplitude of the chatter frequency.

• ICROS
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• v.5 no.4
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• pp.21-28
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• 1999

• Journal of Wetlands Research
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• v.17 no.2
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• pp.118-123
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• 2015

This work has performed to examine the operation status of regeneration and scrubber system of cold rolling mill plant and established the DIWS(Dip Injection Wet Scrubber) system for the removal of hydrochloric acid with micro bubble. When the initial 22.3 ppm of HCl gas was injected into the system, the average exhaust HCl gas was 0.59 ppm with the removal efficiency of 97.3%. Hydrochloric acid was effectively removed by DIWS system. In the long term monitoring for 10 hours by 5 minutes through TMS(Tele Monitoring System), the average exhaust HCl gas was stably kept 0.69 ppm, which was also verified by manual measurement.