scholarly journals Study of rollers box passes influence on formation of thermocyclic fractures under conditions of 3270/150 wire rod hot mill of “Belorussky steel-works – managing company of “BMK” holding

2019 ◽  
Vol 75 (1) ◽  
pp. 80-85 ◽  
Author(s):  
A. V. Strel’chenko ◽  
I. A. Zuev ◽  
I. V. Astapenko
Keyword(s):  
Service Life ◽  
Contact Pressure ◽  
Technological Process ◽  
Thermal Stresses ◽  
Side Surface ◽  
Rolling Process ◽  
Surface Heating ◽  
Technological Parameters ◽  
Temperature Expansion ◽  
Simulation Results

Rollers with box passes are widely used in long products manufacturing, that can be explained by better gripping ability and a high drawing out coefficient. However, along with the stated advantages there are considerable drawbacks – formation of an erosion net at a pass bottom and side fractures at side outlets. Study of main technological parameters of rolling process influence on wear, its value and character of distribution along a pass perimeter. Possibilities shown to decrease or redistribute the wear aimed at an increase of rollers service life. Results of reasons study of thermocyclic fractures formation at side outlets of box passes presented. By application of simulation three digital experiments were made: a base one – according to parameters of existing technological process and two being proposed, in which a pass outlet geometry was varied, estimated its influence on the side surface heating, contact pressure and contact with strip. Based on the experiments simulation results analysis the following was determined: formation of side fractures takes place as a result of uneven temperature expansion of side surface and pass bottom; considerably longer contact of box pass outlets results in critical expanding thermal stresses at its surface. Besides, it was determined, that by a pass outlet geometry changing it is possible to control the dynamic of thermal expanding of a pass surface and considerably decrease it.

Research into the Effect of Speed Mismatch during Continuous Rolling on the Process Parameters

2021 ◽  
Vol 316 ◽  
pp. 208-213
Author(s):  
Sergey O. Nepryakhin ◽  
Olga V. Vodopyanova
Keyword(s):  
Rolling Process ◽  
Rolling Speed ◽  
Continuous Rolling ◽  
Technological Parameters ◽  
Wire Mill ◽  
Small Deviations ◽  
Simulation Results ◽  
Rolling Torque ◽  
3D Software ◽  
Deform 3D

The paper analyzes the influence of tension (dam) on the technological parameters of the rolling process (spreading, force and rolling torque). For the analysis, a model of continuous rolling in three adjacent stands was developed, using the Deform 3D software. The adequacy of the model was confirmed by comparing the experimental data from the small-section wire mill 150 and the simulation results. The error in determining the forming was 0.4%, and in determining the power parameters was 11%. Further, a computational experiment was planned, to identify the effect of mismatched of rolling speeds on technological parameters. According to the results of calculations, graphs of changes in technological parameters were constructed. It is established that, even small deviations of rolling speed from the matched mode lead to significant changes in technological parameters.

Application of System Analysis for Technological Processes Investigation

2020 ◽  
Vol 834 ◽  
pp. 24-31
Author(s):  
Marina Polyakova ◽  
Elena Shiriaeva ◽  
Milyausha Iansaitova
Keyword(s):  
Technological Process ◽  
Hot Rolling ◽  
System Analysis ◽  
Rolling Process ◽  
Geometrical Parameters ◽  
Coating Process ◽  
Technological Parameters ◽  
Rolling Operation ◽  
Technological Processes ◽  
Input And Output

System analysis is used as the effective way for design and modification of different kinds of technical systems. Application of system analysis to any technological process allows to present the links between input and output parameters which makes it possible to analyze its effectiveness and effect on the process for manufacturing of the object with necessary level of quality. The paper presents results of system analysis application for multioperational technological processes. The main aim of hot rolling process is manufacturing the hot rolled metal sheet with definite geometrical parameters which are necessary for further cold rolling process. The scheme of hot rolling operation with its input and output links is presented. The obtained results can be used for mathematical modeling of hot rolling operation. It is shown the application of system analysis for technological process of coating on the example of vacuum ion-plasma coating process. Because of existence of operated, noncontrolled, and indignant parameters of the coating process application of system analysis is the effective way for structural analysis of this technical system. It is proposed to supplement system analysis with function-oriented analysis. This approach can state the links between properties of the object which are sufficient for its application and technological parameters of the manufacturing technological process.

A flexible electromagnetic control technique for interference adjustment in large-size sleeved backup rolls

2019 ◽  
Vol 116 (4) ◽  
pp. 405
Author(s):  
Yanfeng Feng ◽  
Wenwen Liu ◽  
Tingsong Yang ◽  
Fengshan Du ◽  
Jingna Sun
Keyword(s):  
Service Life ◽  
Contact Pressure ◽  
Control Method ◽  
Rolling Process ◽  
Control Technique ◽  
Rolled Strip ◽  
Backup Roll ◽  
Periodic Force ◽  
Large Size ◽  
Electromagnetic Control

Large-size sleeved backup rolls including the roll core and roll shell play a crucial role of supporting work rolls in the precision-rolling process. However, since the backup roll endures an unavoidable periodic force during the rolling process, the interference between its roll shell and roll core is correspondingly reduced, which leads to rolled strip defects or a decreased service life of the roll. To solve this problem, an interference electromagnetic control technique (IECT) was proposed for large-size sleeved backup rolls to freely regulate contact pressure between the roll core and roll shell using a thermally driven electromagnetic stick mounted inside the roll core, thereby adjusting the interference for large-size sleeved backup rolls. In this study, a finite element method (FEM) simulation of a ϕ1400 × 1420 mm size sleeved backup roll was built to demonstrate the effect of this technique by analysing contact pressure variations and roll profile curves of the backup roll at various heating times. According to the FEM model, the key parameters of the IECT including frequency and current density were optimized based on the simulation results. Compared with the conventional rolling process, the electromagnetic control method on the interference adjustment of the large-size sleeved backup roll is shown to be a possible alternative for a better strip shape with a much longer service life.

Functional and operational risk as a criterion for assessing the durability of an autonomous energy system

2019 ◽  
Vol 12 (1) ◽  
pp. 56-62 ◽  
Author(s):  
A. O. Nedosekin ◽  
A. V. Smirnov ◽  
D. P. Makarenko ◽  
Z. I. Abdoulaeva
Keyword(s):  
Service Life ◽  
Structural Reliability ◽  
Residual Life ◽  
Fuzzy Random Variable ◽  
Operational Risk ◽  
Energy System ◽  
Technical System ◽  
Residual Service Life ◽  
Technological Parameters ◽  
Residual Service

The article presents new models and methods for estimating the residual service life of an autonomous energy system, using the functional operational risk criterion (FOR). The purpose of the article is to demonstrate a new method of durability evaluation using the fuzzy logic and soft computing framework. Durability in the article is understood as a complex property directly adjacent to the complex property of system resilience, as understood in the Western practice of assessing and ensuring the reliability of technical systems. Due to the lack of reliable homogeneous statistics on system equipment failures and recoveries, triangular fuzzy estimates of failure and recovery intensities are used as fuzzy functions of time based on incomplete data and expert estimates. The FOR in the model is the possibility for the system availability ratio to be below the standard level. An example of the evaluation of the FOR and the residual service life of a redundant cold supply system of a special facility is considered. The transition from the paradigm of structural reliability to the paradigm of functional reliability based on the continuous degradation of the technological parameters of an autonomous energy system is considered. In this case, the FOR can no longer be evaluated by the criterion of a sudden failure, nor is it possible to build a Markov’s chain on discrete states of the technical system. Assuming this, it is appropriate to predict the defi ning functional parameters of a technical system as fuzzy functions of a general form and to estimate the residual service life of the technical system as a fuzzy random variable. Then the FOR is estimated as the possibility for the residual life of the technical system to be below its warranty period, as determined by the supplier of the equipment.

scholarly journals The Chosen Aspects of Skew Rolling of Hollow Stepped Shafts

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 764
Author(s):  
Jarosław Bartnicki ◽  
Yingxiang Xia ◽  
Xuedao Shu
Keyword(s):  
Cross Section ◽  
Rolling Mill ◽  
Metal Flow ◽  
Experimental Tests ◽  
Rolling Process ◽  
Numerical Control ◽  
Technological Parameters ◽  
Flow Mechanisms ◽  
The Individual ◽  
Skew Rolling

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.

Design of Pipe Steel Hot Rolling Technological Process Based on System Analysis

2021 ◽  
Vol 316 ◽  
pp. 449-454
Author(s):  
Elena Shiriaeva ◽  
Marina Polyakova
Keyword(s):  
Technological Process ◽  
Hot Rolling ◽  
Steel Sheet ◽  
System Analysis ◽  
Pipe Steel ◽  
Rolling Process ◽  
Technological Operation ◽  
Hot Rolling Process ◽  
Wide Range ◽  
Material Energy

Pipe steel sheet is manufactured by hot rolling technological process. Technological regimes of every technological operation can vary in a wide range affecting pipe steel sheet properties. It is shown that system analysis provides the effective way for searching out the basics for mathematical modeling of multi-variant technological processes. The detailed scheme of steel sheet hot rolling process is presented, determining its input and output parameters. Flows of material, energy, and information are presented for each technological operation. Metallurgical concept of pipe steel manufacturing is shown as the basics for competitive product manufacturing. It is proposed to analyze the hot rolling process as a set of target functions, which will make it possible to achieve the pipe steel sheet with the desired level of mechanical properties. The proposed approach based on system analysis allows to find tendencies for further development of hot rolling.

scholarly journals Test Rig for Applied Experimental Investigations of the Thermal Contact Resistance at the Blade-Rotor-Connection in a Steam Turbine

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Dennis Toebben ◽  
Xavier E. R. de Graaf ◽  
Piotr Luczynski ◽  
Manfred Wirsum ◽  
Wolfgang F. D. Mohr ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Steam Turbine ◽  
Contact Pressure ◽  
Rotational Speed ◽  
Thermal Contact Resistance ◽  
Thermal Stresses ◽  
Thermal Contact ◽  
Experimental Investigations ◽  
Molybdenum Steel ◽  
Bottle Neck

Recent studies have shown that in a prewarming, respectively, warm-keeping operation of a steam turbine, the blades and vanes transport most of the heat to the thick-walled casing and rotor. Thereby, a thermal bottle-neck arises at the connection between the blade root and the rotor. The thermal contact resistance (TCR) at these interfaces affects the temperature distribution and thus the thermal stresses in the rotor. The present paper introduces an experimental setup, which is designed to quantify the TCR at the blade-rotor-connection of a steam turbine. An uncertainty analysis is presented, which proves that the average measurement uncertainties are less than one percent. The experiments especially focus on the investigation of the contact pressure, which is a function of the rotational speed. Therefore, the results of several steady-state measurements under atmospheric and evacuated atmosphere using a high temperature-resistant chromium-molybdenum steel are presented. For the evaluation of the TCR, a numerical model of the specimen is developed in addition to a simplified 1D approach. The results show a significantly increasing TCR with decreasing contact pressure, respectively, rotational speed.

scholarly journals Numerical Simulation Study on the Front Shape and Thermal Stresses in Growing Multicrystalline Silicon Ingot: Process and Structural Design

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1053
Author(s):  
Chengmin Chen ◽  
Guangxia Liu ◽  
Lei Zhang ◽  
Guodong Wang ◽  
Yanjin Hou ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Thermal Stress ◽  
Thermal Stresses ◽  
Simulation Method ◽  
Power Ratio ◽  
Radial Temperature ◽  
Front Shape ◽  
Simulation Results ◽  
Insulation Block ◽  
Transient Numerical Simulation

In this paper, a transient numerical simulation method is used to investigate the effects of the two furnace configurations on the thermal field: the shape of the melt–crystal (M/C) interface and the thermal stress in the growing multicrystalline ingot. First, four different power ratios (top power to side power) are investigated, and then three positions (i.e., the vertical, angled, and horizontal positions) of the insulation block are compared with the conventional setup. The power ratio simulation results show that with a descending power ratio, the M/C interface becomes flatter and the thermal stress in the solidified ingot is lower. In our cases, a power ratio of 1:3–1:4 is more feasible for high-quality ingot. The block’s position simulation results indicate that the horizontal block can more effectively reduce the radial temperature gradient, resulting in a flatter M/C interface and lower thermal stress.

scholarly journals IMPROVING DYNAMIC REGIME OF ROLLING FOR INCREASING DURABILITY OF BALL-ROLLING MILL ROLLS

2019 ◽  
Vol 61 (12) ◽  
pp. 927-932 ◽  
Author(s):  
V. Yu. Rubtsov ◽  
O. I. Shevchenko ◽  
M. V. Mironova
Keyword(s):  
Contact Pressure ◽  
Rotational Speed ◽  
Rolling Mill ◽  
Experimental Studies ◽  
Rolling Process ◽  
Operating Conditions ◽  
Frequency Method ◽  
Rolling Mills ◽  
Ball Rolling ◽  
Progressive Technology

One  of  the  important  reasons  for  the  downtime  of  ball  rolling  mills  is  replacement  of  rolls  due  to  their  wear  and  tear.  The  degree  and  zones  of  critical  wear  of  ball  rolling  rolls  are  investigated  in  the  article, where the greatest wear is observed over the flanges in zone of billet  capture.  Conditions  necessary  to  capture  the  blank  and  to  perform  rolling  process  are  analytically  determined.  Variable  frequency  method  of  roll  rotations  is  proposed  as  a  progressive  technology  for  blank supply. The results of tests for its variations in accordance with  linear  and  quadratic  law  are  presented.  Known  formulas  determining  average  strain  rate  at  rolls  rotational  speed  change  are  converted  for  linear and quadratic dependences. Experimental studies have been carried  out  in  conditions  of  EVRAZ  Nizhnetagilsky  Metallurgical  Plant  ball rolling mills during rolling of 60mm ball made of Sh-3G steel. Experiments  were  performed  for  given  parameters  of  manual  change  in  rolls rotation speed at blank capture by rollers. The results have shown  a  significant  effect  of  change  in  rotational  speed  on  average  specific  pressure during blank capture. Evaluation of torque-time and average  contact  pressure  for  calculated  and  experimental  data  are  presented.  Empirical characteristics are also described at variable rotational speed  of rolls according to linear and quadratic law. Acceptable convergence  of results of calculated and empirical characteristics is determined. Engineering solution has been proposed for that task. It consists in installation of a thyristor converter. This solution allows reduction of rolls  speed before blank capture. Also, this solution will increase frequency  to  the  nominal  value  according  to  the  given  law  after  blank  capture.  As an obtained result, there is uniform distribution of average contact  pressure over the entire length of the roll under different operating conditions  of  mill  in  automatic  mode. Application  of  this  technique  will  reduce wear degree of the rolling tool. At the same time, productivity  of ball rolling mill will be maintained. Rolls consumption and number  of rolls change will decrease due to rolls wear.

Influence of Forming Residual Stresses on the Welding Distortions of Two Thick Plates

2009 ◽  
Vol 83-86 ◽  
pp. 125-132 ◽  
Author(s):  
Sebastien Gallée ◽  
Antoine Martin ◽  
Vincent Robin ◽  
Daniel Nelias
Keyword(s):  
Numerical Simulation ◽  
Electron Beam ◽  
Heat Source ◽  
Residual Stresses ◽  
Electron Beam Welding ◽  
Initial Conditions ◽  
Rolling Process ◽  
Vacuum Vessel ◽  
Thick Plates ◽  
Simulation Results

The manufacturing of the ITER (International Thermonuclear Experimental Reactor) vacuum vessel involves the welding of thick deformed plates. The aim of this study is to investigate the influence of forming residual stresses on the welding distortions of two thick plates. The plates are deformed using a three point rolling process. A first numerical simulation is performed to investigate the residual stresses induced by this process. The forming residual stresses are taken into account as initial conditions to perform the electron beam welding simulation of a deformed plate. This simulation first requires calibrating the heat source. Two welding simulations are then performed: the first one with residual stresses and the second one without. The comparison of the simulation results points out a low effect of the residual stresses on the electron beam welding distortions. As a result, in the next electron beam welding simulations of the vacuum vessel, no forming residual stresses will be taken into account.

Sign in / Sign up

Export Citation Format

Share Document