Dynamics of exit section of automatic mill of pipe rolling line

2021 ◽  
Vol 77 (2) ◽  
pp. 175-186
Author(s):  
S. R. Rakhmanov
Keyword(s):  
Differential Equations ◽  
Mechanical System ◽  
Technological Process ◽  
Dynamic Models ◽  
Dynamic Processes ◽  
Exit Section ◽  
Pipe Rolling ◽  
Automatic Mill ◽  
Hollow Billet ◽  
Rolling Line

Nonuniformity of pipe wall thickness is one of significant indices, determining quality of hot-rolled seamless pipes. One of the reasons of increased nonuniformity arising is dynamics of exit section mechanisms of pipe rolling line (PRL). Results of study of mandrel holding mechanism dynamics of PRL presented. Dynamic models of exit section, accounting parameters of technological process and inertia of a rolled hollow billet elaborated, which enabled to determine the character of dynamic processes at the exit section of PRL automatic mill. Differential equations of exit section elements motion at the exit section of PRL automatic mill were made up. The solution of the differential equations system was obtained in a numerical form by application of Runge‒Kutta method for correspondent dynamic models of exit section based on the example of calculations for ТПА-350 automatic mill. The pattern of dynamic processes arising at the exit section was specified at realization of the whole technological process of a hollow billet rolling at automatic mill, taking into consideration alternative action from the side of deformation center and mass of the rolled hollow billet. It was shown, that the specified solution of the task for three advanced dynamic models of mechanical system considerably differs from those of the known mathematical models. It was established, that the dynamics of the mandrel holding mechanism of ТПА-350 automatic mill equivalently form the mechanism of finished pipes geometry forming. Analysis of dynamic models of the mill exit section enabled to select the necessary technological and dynamic parameters of the mechanical system, to determine stable modes of hollow billets rolling at the ТПА-350 automatic mill. Results of the study of dynamics of exit section ТПА-350 automatic mill presented. A scheme of modernization of the exit section ТПА-350 automatic mill proposed, which enables to realize rational modes of operation accounting level of mechanical system dynamics and to control quality (geometric parameters) of the rolled pipes.

scholarly journals COMPREHENSIVE STUDY OF THE DYNAMICS OF THE RETAINING MECHANISM OF THE AUTOMATIC MILL

2021 ◽  
pp. 76-88
Author(s):  
Suleiman Rakhmanov ◽  
Sergey Zdanevich
Keyword(s):  
Mathematical Models ◽  
Mechanical System ◽  
Technological Process ◽  
Dynamic Models ◽  
Retention Mechanism ◽  
Dynamic Processes ◽  
Longitudinal Rolling ◽  
Automatic Mill ◽  
Rod System ◽  
Output Side

The results of the study of the dynamics of the mechanism for holding the mandrel of an automatic TPA mill are presented. The value of the axial force acting on the mandrel and the rod system of the mechanism of its holding is determined. Developed models of the mandrel retention mechanism have been developed, which made it possible to establish the nature of the development of dynamic processes on the output side of the automatic mill, taking into account the force parameters of the longitudinal rolling process of the sleeve and the parameters of the output side of the automatic mill. Mathematical models of the mandrel retention mechanism have been developed, taking into account the parameters of the technological process and the inertness of the rolled sleeve. The solution of the system of differential equations with variable coefficients is implemented numerically using the Runge-Kutta method for the corresponding dynamic models of the mandrel retention mechanism on the example of calculating the automatic mill TPA 350. The picture of the formation of dynamic processes in the mandrel retention mechanism during the implementation of the entire technological process of pipe production on an automatic mill has been clarified. taking into account the variable impact from the deformation zone and the change in the mass of the rolled sleeve. For various dynamic models, numerical solutions of problems were implemented, which made it possible to select the necessary technological and dynamic parameters of the mechanical system, to assign stable modes of rolling the sleeves on the automatic mill TPA 350. It is shown that the refined solution of the problem for three developed dynamic models of the mechanical system differs significantly from the previously known mathematical models. It has been established that the dynamics of the mechanism for holding the mandrel of the automatic TPA 350 mill is equivalent to the formation of the mechanism for the formation of different wall thickness of pipes. A mechanism for stabilizing the dynamics of the mandrel holding mechanism by separating the sections of the output side of the mill is proposed.

scholarly journals Study of the dynamics of the working cell of the automatic mill of the pipe-rolling unit

2018 ◽  
pp. 74-80
Author(s):  
S.R. Rakhmanov ◽  
V.T Vyshinskyi
Keyword(s):  
Mathematical Model ◽  
Differential Equations ◽  
Mechanical System ◽  
Equations Of Motion ◽  
Retention Mechanism ◽  
Operating Conditions ◽  
Dynamic Processes ◽  
Real Spectrum ◽  
Pipe Rolling ◽  
Automatic Mill

Purpose. Determining the real spectrum and the level of dynamic loads would make it possible to develop recommendations for improving the TPA-350 automatic mill, with the aim of expanding its technological capabilities, improving the reliability of operation and durability. Metodology. This work was carried out on the basis of the development of a mathematical model of dynamic processes in the mechanical system of an automatic TPA mill, where an attempt was made to identify the features of the functioning of a working stand with a rolled sleeve in the formulation of dynamic problems. Obviously, the proposed approach is more correct and convenient when studying complex dynamic phenomena in the elements of an automatic TPA mill. Findings. The results of the study of the dynamics of the working stand of the automatic mill of the pipe-rolling unit (TPA) are given The basic parameters of the functioning of the working stand, such as the automatic mill TPA 350, are established, and a mathematical model of the basic problem of the dynamics of a mechanical system is developed. The differential equations of motion for the selected model of the working stand and the elastic elements of the bed retention mechanism on the support nodes of the automatic TPA mill have been compiled. The corresponding patterns of oscillations of the working stand were obtained. Some features of the functioning of the working stand are identified by the example of an automatic mill TPA 350. The dynamic parameters of the working stand of the mill, affecting the difference in the thickness of the rolled sleeves, are established. Originality. The interrelation of the working stand dynamics with the operating conditions of an automatic TPA mill on the basis of a simplified mathematical model of dynamic processes is established. A mathematical model of the mechanical system of a working working stand of an automatic TPA mill has been compiled. In the most general form, the mechanical system of a working stand of a mill is described using differential equations describing the behavior of the selected design scheme of a system with two degrees of freedom. Practical value. A scheme has been proposed for modernizing the working stand and the mechanism for holding the working stand of the TPA-350 automatic mill. IL. 4. Biblography: 8 titles.

Study of the dynamics of ТПА 350 automatic mill working stand elements

2020 ◽  
Vol 76 (8) ◽  
pp. 830-840
Author(s):  
S. R. Rakhmanov ◽  
V. V. Povorotnii
Keyword(s):  
Mechanical System ◽  
Dynamic Model ◽  
Maximum Amplitude ◽  
Calculation Scheme ◽  
Dynamic Loads ◽  
Forced Oscillations ◽  
Mass Model ◽  
Automatic Mill ◽  
Hollow Billet ◽  
Oscillation Movement

To form a necessary geometry of a hollow billet to be rolled at a pipe rolling line, stable dynamics of the base equipment of the automatic mill working stand has a practical meaning. Among the forces, acting on its parts and elements, significant by value short-time dynamic loads are the least studied phenomena. These dynamic loads arise during transient interaction of the hollow billet, rollers, mandrel and other mill parts at the forced grip of the hollow billet. Basing of the calculation scheme and dynamic model of the mechanical system of the ТПА 350 automatic mill working stand was accomplished. A mathematical model of dynamics of the system “hollow billet (pipe) – working stand” within accepted calculation scheme and dynamic model of the mechanical system elaborated. Influence of technological load of the rolled hollow billet variation in time was accounted, as well as variation of the mechanical system mass, and rigidity of the ТПА 350 automatic mill working stand. Differential equations of oscillation movement for four-mass model of forked sub-systems of the automatic mill working stand were made up, results of their digital calculation quoted. Dynamic displacement of the stand elements in the inter-roller gap obtained, which enabled to estimate the results of amplitude and frequency characteristics of the branches of the mill rollers setting. It was defined by calculation, that the maximum amplitude of the forced oscillations of elements of the ТПА 350 automatic mill working stand within the inter-roller gap does not exceed 2 mm. It is much higher than the accepted value of adjusting parameters of the deformation center of the ТПА 350 automatic mill. A scheme of comprehensive modernization of the rollers setting in the ТПА 350 automatic mill working stand was proposed. It was shown, that increase of rigidity of rollers setting in the ТПА 350 automatic mill working stand enables to stabilize the amplitude of forced oscillations of the working stand elements within the inter-rollers gap and considerably decrease the induced nonuniform hollow billet wall thickness and increase quality of the rolled pipes at ТПА 350.

scholarly journals Influence of deoxidizing powder on the internal surface of hot-rolled pipes

2019 ◽  
pp. 61-65
Author(s):  
O. V. Rozhkova
Keyword(s):  
Chemical Composition ◽  
Technological Process ◽  
Internal Surface ◽  
Metallographic Analysis ◽  
Pipe Rolling ◽  
Hollow Billet ◽  
Inner Surface ◽  
Hot Rolled

The article describes the experience of using deoxidizing powder in the technological process of production of hot-rolled seamless pipes; the processes that occur when applying to the inner surface of the hollow billet deoxidizing powder. The results of experimental and industrial tests of deoxidizing powder of different chemical composition are presented. The influence of the chemical composition of the deoxidizing powder on the formation of defects on the inner surface of the pipes is shown. Describes the stages of metallographic analysis of the defects on the inner surface of the pipe, provided the reasons for the formation of the defect «pipe rolling lap (skin)».

scholarly journals Laser Opto-Electronic Oscillator and the Modulation of a Laser Emission

2021 ◽  
Author(s):  
Alexander Bortsov
Keyword(s):  
Spectral Line ◽  
Differential Equations ◽  
Low Noise ◽  
Noise Generator ◽  
Dynamic Processes ◽  
Nonlinear Method ◽  
External Modulation ◽  
Mach Zehnder Modulator ◽  
Electronic Oscillator

The autonomous optoelectronic generator (OEO) is considered in the chapter as a source of low-noise oscillations. Differential equations are considered and methods with OEO modulation with direct and external modulation are analyzed. The complexity of both approaches is related to the non-standard way of description of the nonlinear method modulation for the internal (direct) structure and the utilization of the specific Mach-Zehnder modulator for the first stage on external modulation. The purpose of the presentation is to consider the main features of OEO as a low-noise generator. This includes consideration based on the study of differential equations, the study of transients in OEO, and the calculation of phase noise. It is shown that different types of fibers with low losses at small bending radii can be used as a FOLD in OEO. The important role of the choice of a coherent laser for OEO with a small spectral line width is shown. The prospects of using structured fibers with low losses at bends of less than 10 mm in OEO are described. The results of modeling dynamic processes in OEO with direct modulation are presented.

Increasing the stability of the pipe rolling process on an automatic mill

2019 ◽  
Vol 19 ◽  
pp. 2234-2238
Author(s):  
Yury B. Checulin ◽  
Vasily A. Morgunov ◽  
Artem A. Fedulov
Keyword(s):  
Rolling Process ◽  
Pipe Rolling ◽  
Automatic Mill ◽  
The Stability

scholarly journals Robust Low-Rank Discovery of Data-Driven Partial Differential Equations

2020 ◽  
Vol 34 (01) ◽  
pp. 767-774
Author(s):  
Jun Li ◽  
Gan Sun ◽  
Guoshuai Zhao ◽  
Li-wei H. Lehman
Keyword(s):  
Partial Differential Equations ◽  
Differential Equations ◽  
Minimization Problem ◽  
Real World ◽  
Low Rank ◽  
Dynamic Processes ◽  
Complex Data ◽  
Sparse Regression ◽  
Partial Differential ◽  
Regression Methods

Partial differential equations (PDEs) are essential foundations to model dynamic processes in natural sciences. Discovering the underlying PDEs of complex data collected from real world is key to understanding the dynamic processes of natural laws or behaviors. However, both the collected data and their partial derivatives are often corrupted by noise, especially from sparse outlying entries, due to measurement/process noise in the real-world applications. Our work is motivated by the observation that the underlying data modeled by PDEs are in fact often low rank. We thus develop a robust low-rank discovery framework to recover both the low-rank data and the sparse outlying entries by integrating double low-rank and sparse recoveries with a (group) sparse regression method, which is implemented as a minimization problem using mixed nuclear norms with ℓ1 and ℓ0 norms. We propose a low-rank sequential (grouped) threshold ridge regression algorithm to solve the minimization problem. Results from several experiments on seven canonical models (i.e., four PDEs and three parametric PDEs) verify that our framework outperforms the state-of-art sparse and group sparse regression methods. Code is available at https://github.com/junli2019/Robust-Discovery-of-PDEs

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