scholarly journals Analysis of Roll Wear Costs During Multi-Strand Rolling of Ribbed Bars Using New Slitting Pass System

2019 ◽  
Vol 2 (2) ◽  
pp. 267-278
Author(s):  
Dominika Strycharska

Abstract The paper presents a modification of the slitting pass system, which ensured a reduction in roll wear during three-strand rolling of ribbed bars with a diameter of 16 mm, and thus reduced the associated costs. The theoretical and experimental research on the rolling process of ribbed bars with a diameter of 16 mm rolled in three-strand technology was carried out on a D350 18-stand continuous bar rolling mill conditions. To determine the cost of slitting pass wear, the results of numerical calculations of the frictional force unit of work obtained using the Forge2011® computer program was used, as well as empirical calculations.

2015 ◽  
Vol 220-221 ◽  
pp. 898-904 ◽  
Author(s):  
Piotr Szota ◽  
Sebastian Mróz ◽  
Andrzej Stefanik ◽  
Henryk Dyja

Numerical modelling of the round bar rolling process, while considering the wear of passes depending on their shape, was carried out within the present work. The analysis of the rolling process was conducted thus analysing the influence of interstand tension on roll wear. For the theoretical study of the rolling process, Forge2011® was employed, which is finite element method-relying software that enables the thermo-mechanical simulation of rolling processes in a triaxial state of strain. The wear model implemented in Forge2011® permits no quantitative evaluation, but only a comparative analysis of the wear of rolls. In order to use the results of simulation employing the simplified Archard model for the quantitative evaluation of roll wear, it is necessary to define the factor of wear and the hardness of the tool as a function of temperature.


2010 ◽  
Vol 165 ◽  
pp. 294-299 ◽  
Author(s):  
Konrad Błażej Laber ◽  
Henryk Dyja

The paper presents investigation results related to the effect of application of round plain bar normalizing rolling on the selected mechanical properties of finished product. The research was carried out for the process of rolling 38 mm-diameter plain round bars made of constructional steel S355J2G3, based on actual specifications used in industrial conditions in a continuous bar rolling mill. In the course of investigation the yield stress, YS, and the tensile strength, TS, were determined. With the aim of evaluating the effect of controlled (normalizing) rolling on the mechanical properties of the considered steel grade, Zwick Z/100 testing machine was employed and analytical relationships were used. On the basis of performed research work it was established that enhancement of mechanical properties of the considered steel can be obtained as a result of application of the normalizing rolling process.


Mechanik ◽  
2017 ◽  
Vol 90 (1) ◽  
pp. 78-79
Author(s):  
Dominika Strycharska ◽  
Sebastian Mróz ◽  
Piotr Szota

An analysis of the roll wear in the multi-strand rolling of reinforced ribbed bars has been made in the study. For the computer simulations were used two slitting pass system. For determining the wear of the passes, the results of numerical computation of unit friction force work done using the Forge2011® software program.


2010 ◽  
Vol 638-642 ◽  
pp. 2628-2633 ◽  
Author(s):  
Konrad Błażej Laber ◽  
Henryk Dyja ◽  
Sebastian Mróz

The paper presents results of theoretical and experimental studies on the influence of strip temperature reduction at the final stage of the normalizing rolling process in a continuous bar rolling mill on the energy and force parameters. The studies were carried out for 38 mm-diameter round bars of constructional steel S355J2G3 (St52-3 acc. to DIN). At the first stage, numerical modelling of the rolling process was performed for the conditions of the currently used rolling technology. The aim of this stage of the work was to determine the distribution of strip temperature during the rolling process and of strip temperature after the rolling process. The obtained computation results were compared with the measurement results recorded during the actual rolling process using a thermovision camera. A computer program designed for three-dimensional modelling of metal flow during rolling in passes was used for the determination of the distribution of strip temperature during rolling. The second stage of the studies included modelling of the bar rolling technology modified by applying normalizing rolling after introducing accelerated strip cooling at the final stage of rolling. The aim of this stage of the work was to establish the influence of reduced strip temperature on the change in the values of the energy and force parameters of the process. By comparing the computed values of rolling power with those of the permissible power it was found that these values were lower than the permissible power of the rolling machine’s main drives installed in the Rolling Mill under analysis. Thus, it was demonstrated that it was possible to implement the process of normalizing rolling in the conditions of the Shape Mill under study.


2012 ◽  
Vol 706-709 ◽  
pp. 2090-2095
Author(s):  
Konrad Błażej Laber ◽  
Henryk Dyja ◽  
Marcin Kwapisz

The paper presents the results of the numerical modelling and industrial research of the cooling ability of the device for the round plain bars accelerated cooling process. Research were carried out for one of the bar rolling mill technological conditions in a few variants. The paper purpose was determination of the cooling ability of device for accelerated cooling process to checking possibility of the using this device in the rolling line, during normalizing rolling process. Investigation results elaborated in the paper made the basis for determination of the heat exchange coefficients between cooled band and water. In the next stage of this paper numerical modeling of the normalizing rolling process with accelerated cooling of band in the final stage of the rolling process was carried out. In this investigation heat exchange coefficients between band and cooling medium (water), which were determinated with allowance of cooling possibilities of investigated device for band accelerated cooling were used. From the obtained results it was found that in the analysed bar rolling mill it is possible to decrease the band average temperature to about 900 °C, which is required during the normalizing rolling process.


2019 ◽  
Vol 62 (1) ◽  
pp. 15-24
Author(s):  
A. M. Mikhailenko ◽  
D. L. Shvarts

Based on the system approach and on the experience accumulated at theoretical data, design and industrial development of bar rolling, the Chair “Metal Forming” of Ural Federal University develops the universal “Concept of optimum calibration”. The general ideology of roll pass design optimization is stated in article “The concept of optimal bar roll pass design. Report 1. Basic statements”. In the article “The concept of optimal bar roll pass design. Report 2. Calibers space” the structure, appointment and maintenance of the information block reflecting so-called “calibers space” are considered. According to the general concept of optimization, the following task that needs to be solved is the problem of creation of information block so-called “space of schemes of roll pass design” which will be used further as the first space of optimization. The concept “space of schemes of roll pass design of a bar-rolling mill” is considered as the space containing all possible virtual schemes of rolling of a concrete profile on the concrete rolling mill. For formation of the space of schemes of rail calibrations it is necessary to generate separate virtual schemes and to consistently fill this space with them. Thus, the space of calibrations schemes is formed of separate unique calibrations schemes. For formation of this space from separate calibers, it is offered to use the specialized algorithms which are “generators of schemes of roll pass design”. As an example, the structure of the generator prepared for creation of such space for rolling of railway rails is considered. It is revealed that all known rail calibrations can be presented in the form of essentially the same block structure which is used as the central element of the schemes generator of rail calibrations. Usage of described and similar generators in relation to rolling process of a concrete profile on the concrete rolling mill allows obtaining spaces of acceptable schemes of calibrations. Such spaces are necessary for the subsequent optimizing procedures for search of the best calibration scheme from all possible calibrations. The considered approach for creation of calibrations schemes space can be used during creation of computer-aided engineering systems and optimization of calibrations of rolling rolls.


2012 ◽  
Vol 706-709 ◽  
pp. 1533-1538 ◽  
Author(s):  
Piotr Szota ◽  
Sebastian Mróz ◽  
Henryk Dyja ◽  
Anna Kawałek

Numerical modelling of the round bar rolling process, while considering the wear of the passes depending on their shape, was carried out within the present work. For the theoretical study of the rolling process, the Forge2008® was employed, which is finite element method-relying software that enables the thermomechanical simulation of rolling processes in a triaxial strain state. The wear model implemented in the Forge2008® permits no quantitative evaluation, but only comparative analysis of the wear of rolls. In order to use the results of simulation employing the simplified Archard model for the quantitative evaluation of roll wear, it is necessary to define the wear factor and hardness of the tool as a function of temperature. The paper present a methodology for the determination of the quantitative wear of rolls based on the results of computer simulations performed using the Forge2008® software for a selected round pass during rolling of round bars.


2020 ◽  
Vol 14 ◽  
Author(s):  
Xiao-bin Fan ◽  
Hao Li ◽  
Yu Jiang ◽  
Bing-xu Fan ◽  
Liang-jing Li

Background: Rolling mill vibration mechanism is very complex, and people haven't found a satisfactory vibration control method. Rolling interface is one of the vibration sources of the rolling mill system, and its friction and lubrication state has a great impact on the vibration of the rolling mill system. It is necessary to establish an accurate friction model for unsteady lubrication process of roll gap and a nonlinear vibration dynamic model for rolling process. In addition, it is necessary to obtain more direct and real rolling mill vibration characteristics from the measured vibration signals, and then study the vibration suppression method and design the vibration suppression device. Methods: This paper summarizes the friction lubrication characteristics of rolling interface and its influence on rolling mill vibration, as well as the dynamic friction model of rolling interface, the tribological model of unsteady lubrication process of roll gap, the non-linear vibration dynamic model of rolling process, the random and non-stationary dynamic behavior of rolling mill vibration, etc. At the same time, the research status of rolling mill vibration testing technology and vibration suppression methods were summarized. Time-frequency analysis of non-stationary vibration signals was reviewed, such as wavelet transform, Wigner-Ville distribution, empirical mode decomposition, blind source signal extraction, rolling vibration suppression equipment development. Results: The lubrication interface of the roller gap under vibration state presents unsteady dynamic characteristics. The signals generated by the vibration must be analyzed in time and frequency simultaneously. In the aspect of vibration suppression of rolling mill, the calculation of inherent characteristics should be carried out in the design of rolling mill to avoid dynamic defects such as resonance. When designing or upgrading the mill structure, it is necessary to optimize the structure of the work roll bending and roll shifting system, such as designing and developing the automatic adjustment mechanism of the gap between the roller bearing seat and the mill stand, adding floating support device to the drum shaped toothed joint shaft, etc. In terms of rolling technology, rolling vibration can be restrained by improving roll lubrication, reasonably distributing rolling force of each rolling mill, reducing rolling force of vibration prone rolling mill, increasing entrance temperature, reducing rolling inlet tension, reducing strip outlet temperature and reasonably arranging roll diameter. The coupling vibration can also be suppressed by optimizing the hydraulic servo system and the frequency conversion control of the motor. Conclusion: Under the vibration state, the lubrication interface of roll gap presents unsteady dynamic characteristics. The signal generated by vibration must be analyzed by time-frequency distribution. In the aspect of vibration suppression of rolling mill, the calculation of inherent characteristics should be carried out in the design of rolling mill to avoid dynamic defects such as resonance. It is necessary to optimize the structure of work roll bending and roll shifting system when designing or reforming the mill structure. In rolling process, rolling vibration can be restrained by improving roll lubrication, reasonably distributing rolling force of each rolling mill, increasing billet temperature, reasonably arranging roll diameter and reducing rolling inlet tension. Through the optimization of the hydraulic servo system and the frequency conversion control of the motor, the coupling vibration can be suppressed. The paper has important reference significance for vibration suppression of continuous rolling mill and efficient production of high quality strip products.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 764
Author(s):  
Jarosław Bartnicki ◽  
Yingxiang Xia ◽  
Xuedao Shu

The paper presents chosen aspects of the skew rolling process of hollow stepped products with the use of a skew rolling mill designed and manufactured at the Lublin University of Technology. This machine is characterized by the numerical control of spacing between the working rolls and the sequence of the gripper axial movement, which allows for the individual programming of the obtained shapes of parts such as stepped axles and shafts. The length of these zones and the values of possibly realizable cross-section reduction and obtained outlines are the subject of this research paper. The chosen results regarding the influence of the technological parameters used on the course of the process are shown in the present study. Numerical modelling using the finite element method in Simufact Forming, as well as the results of experimental tests performed in a skew rolling mill, were applied in the conducted research. The work takes into account the influence of cross-section reduction of the hollow parts and the feed rate per rotation on the metal flow mechanisms in the skew rolling process. The presented results concern the obtained dimensional deviations and changes in the wall thickness determining the proper choice of technological parameters for hollow parts formed by the skew rolling method. Knowledge about the cause of the occurrence of these limitations is very important for the development of this technology and the choice of the process parameters.


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