Experimental studies on Zr–1%Nb alloy properties in technological conditions of cold pilger tube rolling process

2019 ◽  
Vol 19 (1) ◽  
pp. 268-273 ◽  
Author(s):  
H. Dyja ◽  
A. Kawałek ◽  
K. Ozhmegov
Keyword(s):  
Experimental Studies ◽  
Rolling Process ◽  
Tube Rolling ◽  
Alloy Properties

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 Temperature Change on the Energy Parameters during Round Bars Rolling Process

2015 ◽  
Vol 220-221 ◽  
pp. 887-891
Author(s):  
Piotr Sygut
Keyword(s):  
Temperature Distribution ◽  
Experimental Studies ◽  
Rolling Process ◽  
Uniform Temperature ◽  
Energy Parameters ◽  
Uniform Temperature Distribution ◽  
Charge Length ◽  
Metallic Charge ◽  
Shape Mill ◽  
Length Changes

The paper presents results of experimental studies on the effect of non-uniform temperature distribution over the metallic charge length on the energy parameters change during round bars rolling process. Experimental tests were conducted on the D370 Continuous Shape Mill in industrial works. From the tests carried out, it has been found that the main cause of occurrence of the non-uniform distribution of temperature over the charge length is the process of heating the metallic charge in the walking beam furnace. During rolling of bars from metallic charge with non-uniform temperature distribution over its length, changes in friction conditions in the zone of contact between the band and the rolls and in the plastic properties of steel being rolled occur. For decrease temperature during metallic charge rolling process about 100 °C (Fig. 2) in walking beam furnace, increase of rolling torque and total rolling power about 30% during rolling process metallic charge in first continuous shape mill stand was observed.

The Thermal-Mechanical Coupled FEM Analysis on 3-Roll Continual Tube Rolling PQF Deformation Process

2011 ◽  
Vol 189-193 ◽  
pp. 1670-1674
Author(s):  
Fei Xue Wang ◽  
Feng Shan Du ◽  
Hui Yu
Keyword(s):  
Finite Element Method ◽  
Deformation Process ◽  
Rolling Force ◽  
Three Dimensional ◽  
Coupled Model ◽  
Fem Analysis ◽  
Rolling Process ◽  
Tube Rolling ◽  
Key Nodes ◽  
Good Agreement

Based on the characteristics of PQF deformation process, a thermal-mechanical coupled model of this process is established by the three-dimensional elasto-plastic finite element method. The simulation according to practical rolling process of a certain factory is completed. Some important parameters such as the finished size of the rolled product, the temperature variation curves of the key nodes on the tube, the rolling force and torque of each roller are predicted during this simulation. Comparison between simulation solutions and experiment results shows a good agreement, which means this model is capable of simulating PQF deformation process as well as forecasting product quality.

Influence of Wall Thickness Fluctuation of Pierced Shell on Continuous Tube Rolling Process of Semi-Floating Mandrel Mill

2011 ◽  
Vol 189-193 ◽  
pp. 2382-2386
Author(s):  
Yuan De Yin ◽  
Sheng Zhi Li ◽  
Yong Lin Kang ◽  
Yang Hua Li ◽  
Gong Ming Long ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Rolling Force ◽  
Metal Flow ◽  
Equivalent Plastic Strain ◽  
Rolling Process ◽  
Steel Tube ◽  
Transverse Wall ◽  
Tube Rolling ◽  
Boiler Steel ◽  
Rolling Moment

In continuous tube rolling process, wall thickness reduction per stand will be changed due to wall thickness fluctuation of pierced shell caused by piercing process, which results in changes in metal flow conditions and affects force parameters, deformation parameters, especially transverse wall thickness precision of rolled hollow tube. In this paper, with the aid of commercial FE code MSC.SuperForm, the high pressure boiler steel tube continuous rolling process of a typical hollow tube specification 133.0×4.0mm are simulated based on 133 main pass sequence of 89mm 6-stand semi-floating mandrel mill, and force parameters, equivalent plastic strain, transverse wall thickness precision, outline dimension and real roundness of rolled hollow tube are analyzed and compared on the condition of two different wall thicknesses of pierced shell. Analysis results indicate that force parameters increase with wall thickness of pierced shell, maximal rolling force, rolling moment and mandrel axial force increase 10% or so in the first three stands when rolling pierced shell of wall thickness 11.5mm compared to that of wall thickness 10.5mm. When rolling pierced shell of wall thickness 10.5mm, there exist front and back tensions among the third, the fourth and the fifth stands and outline dimension and real roundness of rolled hollow tube is slightly better. However, transverse wall thickness of rolled hollow tube at the bottom of groove is pulled thin obviously.

The Influence of Rolling Temperature on the Energy and Force Parameters during Normalizing Rolling of Plain Round Bars

2010 ◽  
Vol 638-642 ◽  
pp. 2628-2633 ◽  
Author(s):  
Konrad Błażej Laber ◽  
Henryk Dyja ◽  
Sebastian Mróz
Keyword(s):  
Final Stage ◽  
Rolling Mill ◽  
Metal Flow ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Rolling Process ◽  
Constructional Steel ◽  
Bar Rolling ◽  
Shape Mill ◽  
Rolling Technology

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.

A Computational and Experimental Study of Cold Rolling of Aluminum Alloys With Edge Cracking

2004 ◽  
Vol 126 (1) ◽  
pp. 74-82 ◽  
Author(s):  
S. Ghosh ◽  
M. Li ◽  
D. Gardiner
Keyword(s):  
Finite Element ◽  
Aluminum Alloys ◽  
Cold Rolling ◽  
Experimental Studies ◽  
Rolling Process ◽  
Rolled Strip ◽  
Damage Models ◽  
Friction Laws ◽  
Model Predictions ◽  
Edge Cracking

This paper identifies various modeling issues that are necessary for successful simulation of the cold rolling process by comparing it with experiments on aluminum alloys. It combines considerable experimental studies with finite element simulations using the ABAQUS/Explicit commercial finite element code to identify and evaluate modeling parameters, such as the material properties and friction laws. Damage models are incorporated in the numerical simulations by using plasticity with damage variables e.g., the Gurson-Tvergaard model with evolving porosity and Cockcroft-Latham with damage in terms of plastic work. The 3D model predictions are compared with predictions from 2D models to understand the limitations of 2D simulations in predicting the stresses, strains and evolving damage in the rolled strip.

Numerical and experimental studies on deformation behavior of 5083 aluminum alloy strips in equal channel angular rolling

2016 ◽  
Vol 232 (6) ◽  
pp. 1031-1043 ◽  
Author(s):  
Reza Nemati Chari ◽  
Bijan Mollaei Dariani ◽  
Alireza Fallahi Arezodar
Keyword(s):  
Mechanical Properties ◽  
Deformation Behavior ◽  
Experimental Studies ◽  
Rolling Process ◽  
Al Alloy ◽  
Effective Parameters ◽  
Influence Of Process Parameters ◽  
Fine Grained ◽  
5083 Aluminum Alloy ◽  
5083 Al Alloy

Improvement of mechanical properties of metal strips can be achieved by producing ultra-fine grained microstructure. The equal channel angular rolling process is one of the effective severe plastic deformation techniques which can lead to proper ultra-fine grained structures. In this research, the influence of process parameters such as pre–equal channel angular rolling annealing temperature, number of equal channel angular rolling passes, routes and post–equal channel angular rolling annealing on deformation behavior of 5083 Al alloy is investigated by experimental studies and numerical simulations. Metallurgical investigations revealed that grain refinement and increased dislocation density are two effective parameters on the mechanical strength improvement. The investigation of mechanical properties demonstrated that increasing number of equal channel angular rolling passes leads to a considerable increase in yield stress, ultimate tensile strength and hardness. In contrast, elongation was dramatically reduced. Also, improvement of mechanical properties reaches saturation at a critical strain level, depending on the microstructure evolution. In addition, investigation of effects of post–equal channel angular rolling annealing on the specimens annealed at 415 °C indicated that elongation and toughness increase, accompanying with a low decrease in yield and tensile strengths and hardness. In this study, the equal channel angular rolling process was numerically simulated using ABAQUS software in two different routes for three passes. It is shown that upper roller force is increased by increasing the number of equal channel angular rolling passes, but the rate of this increase is reduced at higher passes.

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