However, when operator reverses mill and rolls capture the slab, drives usually are accelerated, gaps are kept closed by inertial torque of roll, and the dynamics in the driveline is not as high ...
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….
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 ...
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 ...
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
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 ...
through the grains of the metal, the rolling of threads causes improved strength, because of cold working and favorable grain flow. Figure 13.15 Thread-rolling processes: (a) and (c) reciprocating flat dies; (b) two-roller dies. Threaded fasteners, such as bolts, are made economically by these processes, at high rates of production.
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.
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 …
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.
Rolling mills are classified as in Fig. 2. Fig.2. The two-high mill was the first and simplest but production rates tended to be low because of the time lost in returning the metal to the front of the mill. This obviously led to the reversing two-high mill …
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 ...
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).
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 …
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 ...
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 ...
An expression for the dynamic rolling force of a rolling mill is derived in terms of the vibration and process parameters by analyzing the dynamic rolling process. A nonlinear vibration model of the rolling mill rolls is established. The amplitude-frequency and bifurcation equations are obtained using a multi-scale approximation method, to solve the dynamic equation with time …
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.
During the rolling process of thick plate, the nonlinear specific plastic power that derived from the non-linear Mises yield criterion is difficult to be integrated, which has restricted the establishment of a rolling force model. To solve this problem, a new yield criterion is firstly established, and then used to derive a linear specific plastic power.
Double Rolling Mill - Double D2 rolling mill from Durston Tools. The Double D2 Rolling Mill from Durston Tools is a different mill featuring two sets of rolls; one for flat rolling (having side extension rollers incorporating four half rounds) and the other grooved for the square wire rolling. The excellent gear ratios offer 7-1 load reduction on flat rolling and 3.5-1 for wire rolling, and ...
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.
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 …
The planetary rolling mill (Planetenshrägwalzwerk, PSW), as shown in Fig. 1, has been operated successfully in the roughing rolling process.The advantages of PSW include flexibility of workpiece size, low rolling load, low lateral spread of material, and low temperature drop between the leading and tail ends of the rolled workpiece .Because of its high reduction …
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.
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.
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 …
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 ...
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.
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 …
When hot rolling steel in the laboratory, using relatively small rolling mills, values of 4–20 kW/m 2 K appear to be the correct magnitudes. If modelling hot rolling of steel under industrial conditions, values of 50–120 kW/m 2 K are more useful. In both cases, the layer of scale is an important parameter.
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.
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.
Figure 2 shows grooved rolls for a new type of high-lift stands introduced to increase drafts at secondary mills compensating for the absence of blooming-slabbing mills. Roll costs contribute about 5 - 15 % of overall production costs, estimated at about US$ 1-5 per ton of rolled product and per rolling mill stand.
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 …
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 .
2. Roll deformation of 4-high rolling mill. As symmetry of the mill about the mid-span of the rolls, the calculation process involves one half of a roll system. Given in Fig. 1, one half of the roll barrel and the strip are divided into m and n slab elements respectively. The rolling pressure, the pressure between the work roll and backup roll ...
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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