scholarly journals Advancement of Roll-Gap Control to Curb the Camber in Heavy-Plate Rolling Mills

2021 ◽  
Vol 11 (19) ◽  
pp. 8865
Author(s):  
Andrey A. Radionov ◽  
Vadim R. Gasiyarov ◽  
Alexander S. Karandaev ◽  
Boris M. Loginov ◽  
Vadim R. Khramshin
Keyword(s):  
Large Diameter ◽  
Exit Point ◽  
Rolling Mills ◽  
Heavy Plate ◽  
Plate Rolling ◽  
Geometric Precision ◽  
The Asymmetry ◽  
The Difference ◽  
Edge Trimming ◽  
Roll Gap

The quality of steelwork products depends on the geometric precision of flat products. Heavy-plate rolling mills produce plates for large-diameter pipes and for use in shipbuilding, mechanical engineering, and construction. This is why the precision requirements are so stringent. Today’s Mills 5000 produce flat products of up to 5 m in width; the operation of these units shows ‘camber’ defects and axial shift of the roll at the stand exit point. This induces greater loss of metal due to edge trimming and involves a higher risk of accidents. These defects mainly occur due to the asymmetry in the roll gap, which is in turn caused by their misalignment in rolling. As a result, the feed varies in gauge, and the strip moves unevenly. The paper’s key contribution consists in theoretical and experimental substantiation and development of a set of control methods intended to address roll-gap asymmetry. The methods effectively compensate for the asymmetry resulting from the “inherited” wedge, which preexists before the strip enters the stand. They also compensate for the “ongoing” roll misalignment that is caused by the difference in force on the opposite side of the stand during rolling. This comprehensive approach to addressing camber and axial displacement of the feed has not been found in other sources. This paper presents a RAC controller connection diagram that ensures that the roll gap is even across the feed. The paper notes the shortcomings of the design configuration of the controller and shows how it could be improved. The authors have developed a predictive roll-gap asymmetry adjustment method that compensates for the deviations in gauge during the inter-passage pauses. They have also developed a method to control gap misalignment during rolling. The paper showcases the feasibility of a proportional-derivative RAC. The methods have been tested by mathematical modeling and experimentally. The paper further shows oscillograms sampled at Mill 5000 after implementing the developed solutions. Tests confirm far better precision of the screw-down mechanisms on the opposite sides of the stand. This reduces the variation in gauge across the feed and thus curbs the camber defect. As a result, the geometry of the flat improves, and less metal is lost in trimming. The paper further discusses how the RAC controller interacts with the automatic gauge control system. The conclusion is that these systems do not interfere with each other. The developed systems have proceeded to pilot testing.

scholarly journals The Analysis of the Asymmetric Plate Rolling Process in the Finishing Stand 3600/ Analiza Asymetrycznego Procesu Walcowania Blach Grubych W Klatce Wykańczającej 3600

2014 ◽  
Vol 59 (4) ◽  
pp. 1533-1538
Author(s):  
A. Kawałek ◽  
H. Dyja ◽  
M. Knapinski ◽  
G. Banaszek ◽  
M. Kwapisz
Keyword(s):  
Process Parameters ◽  
Rotational Speed ◽  
Shape Factor ◽  
Rolling Process ◽  
Asymmetry Factor ◽  
Asymmetric Rolling ◽  
Rolling Mills ◽  
Plate Rolling ◽  
Strip Shape ◽  
Roll Gap

Abstract In order to enhance the quality of plates, various solutions are being implemented, including normalizing rolling, the process of rolling followed by accelerated cooling, as well as new roll gap control systems. The hydraulic positioning of rolls and the working roll bending system can be mentioned here. The implementation of those systems results in increased loads of the rolling stands and working tools, that is the rolls. Another solution aimed at enhancing the cross-sectional and longitudinal shape of rolled plate is the introduction of asymmetric rolling, which consists in the intentional change of the stress and strain state in the roll gap. Asymmetric rolling systems have been successfully implemented in strip cold rolling mills, as well as in sheet hot rolling mills. The paper present results of studies on the effect of roll rotational speed asymmetry and other rolling process parameters on the change in the shape of rolled strip and the change of rolls separating force for the conditions of normalizing rolling of plates in the finishing stand. The variable process parameters were: the roll rotational speed asymmetry factor, av; the strip shape factor, h0/D; and the relative rolling reduction, ε. Working rolls of the diameter equal to 1000 mm and a constant lower working roll rotational speed of n = 50 rpm were assumed for the tests. The asymmetric rolling process was run by varying the rotational speed of the upper roll, which was lower than that of the lower roll. The range of variation of the roll rotational speed factor, av =vd/vg, was 1.01÷1.15. A strip shape factor of h0/D = 0.05÷0.014 was assumed. The range of rolling reductions applied was ε = 0.08÷0.50. The material used for tests was steel of the S355J2G3 grade. For the simulation of the three-dimensional plastic flow of metal in the roll gap during the asymmetric hot rolling of plates, the mathematical model of the FORGE 2008 ® program was used. For the mathematical description of the effect of rolling parameters on the strip curvature and rolls separating force the special multivariable polynomial interpolation was used. This method of tensor interpolation in Borland Builder programming environment was implemented. On the basis of the carried out analysis can be state, that by using the appropriate relative rolling reduction and working roll peripheral speed asymmetry factor for a given feedstock thickness (strip shape ratio) it is possible to completely eliminate the unfavorable phenomenon of strip bending on exit from the roll gap, or to obtain the permissible strip curvature which does not obstructs the free feed of the strip to the next pass or transferring the plate to the accelerated plate cooling stations. Additionally by introducing the asymmetric plate rolling process through differentiating working roll peripheral speeds, depending on the asymmetry factor used, the magnitude of the total roll separating force can be reduced and, at the same time, a smaller elastic deflection of rolling stand elements can be achieved. As a result smaller elastic deflection of the working rolls, smaller dimensional deviations across its width and length finished plate can be obtained.

scholarly journals Systems of control and diagnostics in integrated APCS of heavy-plate mills.

2021 ◽  
Vol 4 ◽  
pp. 58-69
Author(s):  
G.G. Grabovsky ◽  
◽  
M.G. Ievlev ◽  
S.Ye. Moiseienko ◽  
◽  
...  
Keyword(s):  
Control Systems ◽  
Residual Life ◽  
Technical Condition ◽  
Economic Effects ◽  
Mechanical Equipment ◽  
Diagnostic Systems ◽  
Rolling Mills ◽  
Heavy Plate ◽  
Plate Rolling ◽  
Resource Characteristics

Diagnosing the equipment of complex technological installations is a guarantee of their safe and efficient performance. The aims of the diagnostic systems creation are the following: timely prevention of possible failures and malfunctions of systems and equipment; the necessi-ty of having a complete and holistic picture of the actual technical condition of the operating systems and equipment; high accuracy forecasting of the residual life of the equipment; minimization of cost and increase of efficiency of works on technical conditions monitoring, maintenance, repairs and management of resource characteristics of systems and equipment; continuous improvement, based on objective performance data, actual characteristics of safety, reliability and operational readiness. To such complex technological installations there belongs the equipment of hot rolling shops, for example, mechanical equipment of the mill, electric drive with control systems, devices and control systems for hydraulics, lubrication and cooling management, ventilation stations, pumping stations; switchgear cells (high voltage switches), complex of APCS of heavy-plate mills rolling technical means. The article considers some methods of operational control of the technical condition of the heavy-plate rolling mills equipment. The factors that influence the efficiency of the diagnostic algorithms used in the APCS, in particular, the organization of collection and processing of statistical data on the possibilities of malfunctions and the costs of their search and elimination are determined in the paper. Formalization of methods for construction and description of mathematical models of the object of diagnostics is performed. Utilization of the subsystem of control and diagnostics in the APCS of modern rolling mills provides a significant improvement in the reliability of the APCS of heavy-plate mills rolling, as well as some economic effects.

A vision-based material tracking system for heavy plate rolling mills

2007 ◽  
Author(s):  
Mark Tratnig ◽  
Johann Reisinger ◽  
Helmut Hlobil
Keyword(s):  
Tracking System ◽  
Rolling Mills ◽  
Heavy Plate ◽  
Plate Rolling

Correction method for the asymmetry of the tangential beam in Couette (or Searle) geometry used in rheo-small-angle neutron scattering

2004 ◽  
Vol 37 (3) ◽  
pp. 438-444 ◽  
Author(s):  
Florian Nettesheim ◽  
Ulf Olsson ◽  
Peter Lindner ◽  
Walter Richtering
Keyword(s):  
Neutron Scattering ◽  
Cross Sections ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Correction Method ◽  
Shear Cell ◽  
The Asymmetry ◽  
The Difference ◽  
Scattering Cross Sections ◽  
Final Expression

A method of correcting the asymmetry in the scattering of the tangential beam configuration in a rheo-small-angle neutron scattering experiment is proposed. The asymmetry of the scattering in the tangential beam configuration can be attributed to the difference in pathlength for neutrons that are scattered toward compared with those which are scattered away from the axis of rotation of the shear cell. The pathlength problem is solved and a final expression for the two-dimensional scattering intensity is given. The results from these calculations are compared with experimental data, which offer a different option to correct this asymmetry, namely by just measuring the scattering of H2O/D2O mixtures with absolute scattering cross sections identical to those of the respective samples. However, the situation for anisotropic media is more complex and the correction procedure described here is less effective.

scholarly journals Breaking the symmetry of geminates in diachrony and synchrony

2017 ◽  
Vol 2 ◽  
pp. 164-202 ◽  
Author(s):  
Michela Russo ◽  
Shanti Ulfsbjorninn
Keyword(s):  
Consonant Cluster ◽  
Structural Units ◽  
True Nature ◽  
Internal Forces ◽  
The Asymmetry ◽  
The Difference ◽  
Control Relation

Autosegmentalism invariably represents geminates in a symmetrical one-to-many relationship — as feature bundles or root nodes attached to two structural units: x-slots, moras, or C-slots. This symmetry, however, is often not reflected in their diachronic origin. For instance, in Blevins’ (2008) Type 1 pathway, only the second C of a consonant cluster (CC) ever determines the geminate: CxCy > CyCy, *CxCx (e.g. Latin > Italian). Moreover, although most synchronic processes identify geminates as symmetrical, there is an exception: geminate integrity. Unlike CCs and long vowels (LVs), geminates never ‘break’ by epenthesis: *CyCy > CyVCy. We propose that this is central to understanding the true nature of geminates, and present analyses in two frameworks. The first is ‘control by contiguity’, which uses head-dependent ‘control chains’ (Russo 2013). A control relation applies between a specified and an unspecified position: -C. Inalterability and integrity result from the asymmetry of the geminate’s positions. The second is based on Strict CV. This restricts a geminate’s melody to one of its two skeletal positions. Unlike CC and LVs, geminates do not involve a ‘trapped’ empty V position that could host epenthesis and cause breaking; the difference between LVs and geminates follows from framework-internal forces and suggests that melodic branching always requires licensing. These two approaches share the insight that the representation of geminates is not symmetrical, like that of long vowels.

Static Pressure-Volume Curves for the Lung of the Frog (Rana Pipiens)

1978 ◽  
Vol 76 (1) ◽  
pp. 149-165 ◽  
Author(s):  
G. M. HUGHES ◽  
G. A. VERGARA
Keyword(s):  
Volume Change ◽  
Rana Pipiens ◽  
Static Pressure ◽  
Large Diameter ◽  
The Difference ◽  
Isolated Lungs ◽  
Precise Role ◽  
Different Parts

1. Static pressure/volume curves have been determined for isolated frog lungs inflated with either air or saline. In both cases a hysteresis was present: the pressure required to produce unit change of volume being greater during inflation than deflation. 2. The pressure necessary for a given volume change was less for the saline-filled than the air-filled lungs. The difference between these curves is due to the surface tension at the air/lung interface. 3. Pressure/volume curves for air-filled lungs in situ were similar to curves for isolated lungs. However, a greater pressure was required for the same volume change during both inflation and deflation. 4. Compliance was calculated from different parts of air pressure/volume curves and gave values greater than those obtained using similar calculations for higher vertebrates. 5. These observations support other evidence for the presence of a surfactant in the lung lining of frogs in spite of the relatively large diameter of their ‘alveoli.’ The precise role of such a lining is uncertain and it is concluded that similar forces may be involved during the inflation and deflation of lungs of frogs and higher vertebrates in spite of differences in gross morphology.

Development of a Mathematical Model of Plate Rolling on Hot Reversing Mills

2017 ◽  
Vol 746 ◽  
pp. 48-55
Author(s):  
Vasiliy V. Yashin ◽  
Evgenii V. Aryshenskii ◽  
Erkin D. Beglov ◽  
Maksim S. Tepterev ◽  
Anna F. Grechnikova
Keyword(s):  
Rolling Force ◽  
Work Roll ◽  
Calculation Model ◽  
Production Environment ◽  
Plate Rolling ◽  
Process Reliability ◽  
Calculation Results ◽  
Roll Gap ◽  
Relationship Of ◽  
Force Calculation

Objective of the work: develop a model for calculation of plate exit thickness. This model is supposed to improve process reliability in obtaining specified thickness with +/- 0.5 mm tolerance. The work identifies major influences on obtaining specified thickness and relationship of their effects. Based on derived relationships, the work develops rolling force calculation model with the following inputs: alloy grade, feedstock temperature, feedstock entry and exit gage, feedstock width, rotational speed of the rolls. Mill stand characteristics, like mill stiffness, backlash, work roll behavior, were studied in relation to force and temperature. The resulting model allows to predict the value of work roll gap increase during rolling. The model was validated in production environment and demonstrated high confidence level of calculation results.

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