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Abstract. Equations are derived for the normal roll pressure, specific roll load and torque in hot rolling mills, using the condition for plastic deformation in rolling derived by Orowan, together with von Kármán's equation of equilibrium. Although applying strictly to the rolling of ideal plastic-rigid materials, these equations may be. Chat Now
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The Calculation of Roll Force and Torque in Cold Strip Rolling with Tensions. D. Bland, H. Ford. Engineering. 1948. From an approximate theory, equations are derived for roll force and torque with and without front and back tensions applied to the strip. Where tensions are applied the calculations for each pass….
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Flat Rolling Analysis Results – without 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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through joint efforts with mill builders, new types of rolling mills equipped with such actuators; typical examples of these mills are the 6-high mill with lateral shifting of intermediate rolls (called the HC mill)5) 6)and the pair-crossed roll (PC) mill, which are shown in Fig. 1 (a) and (b), respectively. Technical Review (a) HC-mill (b) PC ...
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The rolling process is shown in Fig. 2.1: Rolling is done both hot and cold. It is accomplishes in rolling mills. A rolling mill is a complex machine having two or more working rollers, supporting rollers, roll stands, drive motor, reducing gear, flywheel, coupling gear etc. Rollers may be plain or grooved depends upon the shape of rolled product.
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derived from the equations of rolling load in Hot Rolling Bland and Ford's program (HRBF). The study developed a numerical model for the estimation of coefficient of friction for steel (HC SS316) of different thicknesses on two high reversing mills.
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However, in this experiment, the rolling load of mill is limited to a maximum value of 200 kN. The rolling force provided by the mill is not high enough to roll the foils to the theoretical minimum achievable thickness. In order to achieve a thickness close to the theoretical minimum, a mill of higher rolling load should be used.
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Stability areas are defined as function of mill and material modulus. An expression for accuracy as function of actual and system mill modulus is derived. Keywords. Control linearities, force control, function generators, metallurgical industries, position control, rolling mills, stability, thickness control.
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The experimental rolling load was calculated by using different analytical models given in table 3. The rolling load is calculated by consideration of strain, strain rate, temperature and composition of the steel using Misaka's equation . The mill current value for a given deformation strain was measured and was converted to the rolling torque.
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The plate rolling experiments were carried out in the laboratory by the rolling mill to ensure the reliability of numerical and analytical calculated results. The diameter of the work roll is 320 mm which is the same as the 'value 1' in Table 1 and the other main process parameters are listed in Table 2.
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load and torque in hot rolling mills. A simplified version of Sims [3] model which ... a 7 stand 4 roll high hot rolling mill. The industrial process data covers ... equation 2 derived by Hitchcock [19] [ ] 2) R is the original roll radius (m), b is the width of the strip (m) and where C is given
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Roll gap model Mill model Tension practices Model parameters Set-up values Adaption parameters Measured values Thickness, tension, speed Roll force, torque, temperature CVC, HS, position bending Coil-data Operator-trims Scheduling 400 350 300 250 200 150 100 50 0 0 0.5 1 1.5 2 Log deformation Yield stress 3542 Rolling mill applications covered ...
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METAL FORMING SCIENCE AND PRACTICE The flattening rate W is a function of the real area of contact area ratio A and the ratio p Y of the mean contact pressure to the plane strain yield stress of the strip, i.e. = A Y p W W, (4.4) The theoretical flattening rate W is in the range 1–8, increasing with increasing mean pressure and falling with increasing area of contact ratio.
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Establishment of a shape control model for twenty-high mill. Taking the laboratory twenty-high mill as the research object, a twenty-high mill shape control model was established by coupling the rolling force model, metal plastic deformation model, tension model and roll elastic deformation model. The main parameters of the twenty-high mill and ...
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Since there are two work rolls Torque Mt = 2P.a Consider two high roll mill as shown in the figure. For one revolution of the top roll the resultant rolling load P moves along the circumference of a circle equal to 2π.a Since there are two work rolls involved, the work done is equal to Work done =2 (2.π.a).P = 4P.π.a
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In this paper, a non-linear quadratic expression of the coefficient of friction at both entry and exit sides have been derived from the equations of rolling load in Hot Rolling Bland and Ford's ...
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Four-row tapered outer bearings are used in high-load applications such as rolling mill roll necks. Related Catalog Spherical roller bearings. These bearings have an outer ring with a spherical track surface, and an inner ring that encloses two …
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In this paper, an inverse analysis technique is used to obtain the flow curve of materials in a hot rolling finishing mill. This technique is based on minimization of the differences between the experimental and computed values. The flow curves and the friction coefficients at roll/work-piece interface are derived from two different models. Model I is based on simple …
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The application of finite element simulation to the problem of roll pass design for round bar rolling is considered. Two roll pass sequences were developed by analytical methods and …
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2. The coupling vibration model with friction of rolling mill. In the study of rolling mill driven by the motor, in order to simplify the model and conform to actual physical meaning, rolling mill drive system is usually abstracted into two parts, which are the motor terminal and the roller terminal according to lumped mass method.
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A set-up model for tandem cold rolling mills. ... expression for the limiting value of roll separating ... of roll force and torque in hot rolling mills. ... For repetitive high peak load applications, use the system peak torque in lb-ft . ... runout mill table roll .
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A method of assessing rolling contact metallic material shear stress fatigue values comprises the steps of deriving, by an ultrasound torsion fatigue test, a relationship between a rolling contact metallic material shear stress amplitude and a load cycles (S1); and determining, from the relationship between the shear stress amplitude and the load cycles derived in the test step …
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Nonlinear dynamic rolling forces in the vertical and horizontal directions are, respectively, established, considering the impact of vertical and horizontal directions vibration of rolls. Then a vertical-horizontal coupling nonlinear vibration dynamic model of rolling mill rolls is proposed, based on the interactions between this dynamic rolling force and mill structure.
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An approach which showed good agreement with real industrial rolling load data can be described by the expression. P = b l d K Q p. where P is the rolling load, b is the width of the rolling stock, K is the hot flow strength of the steel, l d is the length of contact between the rolls and rolling stock, and Q p is a geometrical factor.
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On the basis of theoretical considerations, it was established that strip thickness variation in the rolling of sintered materials affects the rolling force. An expression has been derived describing the relationship between the permissible rolling force variation and the tolerance limit for a given type of product. The fact that these two quantities are interrelated shows the need …
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The thickness of the plate delivered from the rolling mill can be expressed as a function of the cooperating forces produced during operation of the mill by the following expression 2 o GlP) (Q/ g) G/B) (Equation 1) where h, no-load roll gap between the work rolls P= rolling load M the modulus of the rolling mill parts, which modulus is a ...
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In this paper, a non-linear quadratic expression of the coefficient of friction at both entry and exit sides have been derived from the equations of rolling load in Hot Rolling Bland and Ford's program (HRBF).
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In the metallurgical industry, hydraulic automatic gauge control (HAGC) is a core mechanism for thickness control of plates used in the rolling process. The stability of the HAGC system's kernel position closed-loop is key to ensuring a process with high precision, speed and reliability. However, the closed-loop position control system is typically nonlinear, and its stability is …
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FOUR HIGH ROLLING MILL . To analyze rolling without slipping, we first derive the linear variables of velocity and acceleration of the center of mass of the wheel in terms of the angular variables that describe the wheel's motion. The situation is shown in (Figure). Figure 11.3 (a) A wheel is pulled across a horizontal surface by a force.
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Accurate prediction of the rolling force is critical to assuring the quality of the final product in steel manufacturing. Exit thickness of plate for each pass is calculated from roll gap, mill spring, and predicted roll force. Ideal pass scheduling is dependent on a precise prediction of the roll force in each pass. This paper will introduce a concept that allows obtaining the material model ...
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