how to control eccentricity problem in hot rolling mill
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Rolling of hot strip and strip defectsIspatGuru
For rolling of hot strip the slabs are heated initially at 1100 deg C to 1300 deg C The temperature in the last finishing stand of the hot strip mill varies from 700 deg C to 900 deg C It is always to be above the upper critical temperature to produce uniform equiaxed ferrite grains.
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quality a powerful controller is need Rolling mill simulator
Rolling mill simulator A new platform for testing analysis and optimization of cold rolling mills Axel Brickwedde Frank Feldmann Nicolas Soler The cold rolling of flat metal products especially in tandem or multi stand mills is a highly complex process where the product quality is
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Roll Eccentricity Control for Strip Rolling Mills
An in depth review of the roll eccentricity control design problem is provided which encompasses a number of recent novel design contributions and includes experimental results from two separate steel tandem cold rolling mill installations.
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FEATURING ROLLING AND PROCESSING
hot strip mills has increased the requirements for precise mass flow and thickness control As an initial step to meet these demands Primetals Technologies has developed a new control concept for rolling ultra thin hot rolled strip in the finishing mill of an ESP line Referred to as ultra thin rolling control the system
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Multi resolution wavelet method for roll eccentricity
In order to compensate the roll eccentricity in hot strip rolling process a multi resolution wavelet transform method was proposed This wavelet method has quiet good localization characteristic in both time domain and frequency domain To eliminate frequency aliases inhered in Mallat algorithm an anti aliasing algorithm combining fast Fourier transform FFT and inverse fast Fourier
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Strip Thickness Control of Cold Rolling Mill with Roll
where M is mill modulus The BISRA relationship is used to develop a thickness feedback signal for closed loop control To control the output thickness the motion of hydraulic cylinder con trolling the roll gap position is such that produces the desired output thickness Roll eccentricities are caused by axial deviations between the roll barrel and the roll necks due to irregularities in the mill rolls and/or roll bearings These irregularities cause cyclic deviations in the strip thickness at the output of a mill
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The Hot Rolling ProcessCalifornia Steel
The Hot Rolling Process The primary function of the Hot Strip Mill is to reheat semi finished steel slabs of steel nearly to their melting point then roll them thinner and longer through 12 successive rolling mill stands driven by motors totaling 77 000 hp and finally coiling up the lengthened steel sheet for transport to the next process.
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Application of Dynamic Deadband Eccentricity Filter in GM
The problem of roll eccentricity has become one of important factors to affect the quality of strips as downstream industries require improvement of the strip quality Reducing thickness control precision as little as possible is incompatible with restraining roll eccentricity perturbations on the requirement of the deadband size for the deadband drift method DDM with fixed deadband width.
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Roll Eccentricity Control by Using a Bandpass Filter
Thickness deviations of the steel plates in the rolling mill process is mainly caused by the roll eccentricity of the back up roll BUR In this paper a bandpass filter with high gain in the given frequency is introduced which is able to overcome the roll eccentricity of BUR and is very simple compared with other roll eccentricity control REC methods.
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HOT ROLLING PRACTICEAn Attempted Recollection
HOT ROLLING PRACTICEAn Attempted Recollection Saral Dutta B Tech Hons I.I.T Executive Director ISP RMD SAIL Retired Rolling is a metal forming process in which metal stock is passed through a pair of rolls There are two types of rolling processflat and profile rolling In flat rolling the final shape of the product is either
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Improvement of Accuracy for Gauge and Elongation
above control systems a desired elongation is realized by control ling the rolling force of the mill by a hydraulic screw down control system 2.3 AEC for skin pass mill of continuous processing line 2.3.1 Conventional AEC methods and their problems In most cases an in line skin pass mill
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Common Rolling Defects and How to Combat Them
Rolling is the process in which a metal stock passes through rollers to reduce and unify thickness Cold rolling occurs when performed at temperatures below the recrystallization point When done at temperatures above the recrystallization point it s referred as hot rolling Below are some of the common rolling defects and their remedies
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A SURVEY OF THE LOOPER TENSION CONTROL
and mass flow in hot rolling mills can be satisfied by proper control of the strip tension and looper angle Figure 1 shows the tension and looper control in a typical finishing mill Traditionally looper angle control has been per formed by changing the rotating speed of a main motor but there has been no tension feedback control because
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Roll Eccentricity Control Using Identified Eccentricity of
Roll eccentricity is a periodic disturbance caused by a structure of back up rolls in rolling mills and it affects product thickness accuracy It cannot be measured directly by sensors so it should be identified by measured thickness or measured roll force When there is a large difference of diameters between top and bottom back up roll the performance of roll eccentricity control using
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ANALYSIS OF CAMBER FORMATION SUPPRESSION AND
CONTROL IN HOT ROLLING OF WEDGE SHAPED SLABS BY process automation systems for hot strip mills Therefore detailed transient 3D models of the problem for many years cf e.g 5–8 and most of such studies are based on qualitative camber assessment pilot plant trials and numerical simulation results it has to be emphasized
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CiteSeerX ROLL ECCENTRICITY CONTROL WITH THE
CiteSeerXDocument Details Isaac Councill Lee Giles Pradeep Teregowda The Force Feed Forward FFF System is the only hot strip mill AGC system in the world today which does not incorporate the BISRA principle for gage control Instead using a revolutionary control algorithm FFF has proven in five installations in North and South America that steelmakers need not replace their
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Rolling Technology and Theory for the Last 100 Years The
At the time when the past basic research and development flowered development of many new type rolling mills with the crown shape control function were reported 72 73 74 75 76 77 78 A pair cross rolling mill with a big effect of profile control for hot rolling mills was put to practical use 79 which became a standard rolling mill for the
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Looper and tension control in hot rolling mills A survey
This paper considers some of the control issues in hot rolling mills Hence to set the context first we give a brief description of a typical process The role of a hot strip mill process is to roll the slabs produced in a continuous casting process and produce strips of thickness 0.8–20 mm Fig 1 shows
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Quality Improvement in Finished Cold Rolled
quality control of rolling process has a vital role In present is the customer of the Hot rolling mill Hot rolled product is Improper coiling Poor quality of oil used Spread roll problem Improper coiling Uncoiler assembly rough handling by crane less
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A SURVEY OF THE LOOPER TENSION CONTROL
and mass flow in hot rolling mills can be satisfied by proper control of the strip tension and looper angle Figure 1 shows the tension and looper control in a typical finishing mill Traditionally looper angle control has been per formed by changing the rotating speed of a main motor but there has been no tension feedback control because
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Prognosis technology for roll eccentricity based on the
The result demonstrated that the eccentricity influence of the first stand is the most serious and the eccentricity influence of the fifth stand in five stand cold tandem mill is second Furthermore the effect of watermarks before hot rolling was the primary factor of periodical rolling force variation.
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PriMetals 1 2015 72 2
Logically the strip width in a hot strip mill is mostly influenced by pressing or vertical rolling of the strip in the roughing mill Width deviations after the finishing mill arise from width deviations in front of the finish ing mill or from a width spread anomaly that takes place inside the finishing mill The behavior of width spread in a
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Technical Report UDC 621 771 25 Progress of Bar and
rolling mills 8 stand roughing rolling mill 4 stand intermediate rolling mill and 4 stand finishing rolling mill was built by Morgan Sumitomo Heavy Machinery Co Ltd. In the 1980s the aimed qual ity of products was shifted toward high value added special steel quality and to achieve this in 1986 a three roll finishing rolling
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How To Control Eccentricity Problem In Hot Rolling Mill
and roll eccentricity problem is the ii the structure of four high 4 h rolling mill so as the strip gauge control system is presented hot rolling and 5 mill stands in cold rolling Learn More Hot Rolling And Rolling
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Real time tension control in a multi stand rolling system
The problem of real time tension control in a metal strip processing line is addressed The tension in a metal strip changes due to not only the speed difference but also thickness changes at the ends of a span The mathematical dynamic model which describes relationship between the tension change and the roll speed change is improved to include the effect of the strip thickness change on
Get PriceHot Rolling Mill Hydraulic Gap Control HGC thickness
accuracy in thickness control in metal rolling area If the required accuracy of hot rolling mills can be achieved then in some cases cold rolling is not even required which can result in a radical decrease of production costs The schematic structure of a typical aluminum hot reversing rolling mill can be seen in Figure 1.
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Polynomial LQG control of back up roll eccentricity gauge
Abstract The issues relating to the polynomial LQG optimal control design method applied to the control of strip gauge in the single stand of a cold rolling mill are considered In particular the problem of controlling the Back Up Roll eccentricity gauge variation caused by non circular Back Up Rolls is treated A new polynomial systems formulation for this problem is presented and the
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Deformation ProcessingRolling
Flat Rolling Analysis Resultswithout front and back tension p p µp µp σ σ x x dσ x Stresses on Slab in Entry Zone Stresses on Slab in Exit Zone p p µp µp σ σ x x dσ x Using slab analysis we can derive roll pressure distributions for the entry and exit zones as h 0 and h b are the same thing 2tan1 ff RR H hh − φ = 0 0 2
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Unwind/rewind eccentricity control for rolling mills
Unwind/rewind eccentricity control for rolling mills United States Patent Abstract A method of rolling material in a rolling mill in which the material is directed from an unwind coil of the material to the mill and/or to a rewind coil of the material from the mill the material being under tension as it is directed to and from the
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Advanced Process and Quality Control in Hot Rolling
3.1 Key Feature of Process Control Detection of Periodic Defects Rolls and rollers are the most heavily used parts of a rolling mill Due to wear from contacting hot material with great force their lifetime is limited Although rolls are refurbished in the roll shop regularly they occasionally crack before the end of the usual production cycle.
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Roll eccentricity compensation based on anti aliasing
Roll eccentricity is an important factor causing thickness variations during hot strip rolling and might define the limit of strip thickness control accuracy An improved multi resolution wavelet transform algorithm was proposed to compensate for the roll eccentricity The wavelet transform method had good localization characteristics in both the time and frequency domains for signal analysis
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Online Monitoring System Design for Roll Eccentricity in
This paper deals with the parameter estimation and online monitoring of roll eccentricity in rolling mills Roll eccentricity induced disturbances can result in strip thickness deviation and
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GENERAL ASPECTS OF ROLL COOLING FOR HOT
rolling mill dedicated roll cooling systems are required to fulfill the required functions Examples are suitable roll cooling and lubricationsystems to fully utilize the advantages of HSS rolls in hot strip mills and selective roll cooling systems as a method to control the flatness of the strip in cold rolling mills.
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