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.

Influence of Roll Speed Schedule on Continuous Tube Rolling Process of Semi-Floating Mandrel Mill

2010 ◽  
Vol 148-149 ◽  
pp. 563-568 ◽  
Author(s):  
Yuan De Yin ◽  
Sheng Zhi Li ◽  
Yong Lin Kang ◽  
Yang Hua Li ◽  
Gong Ming Long ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Rotational Speed ◽  
Rolling Force ◽  
Rolling Process ◽  
Steel Tube ◽  
Transverse Wall ◽  
Tube Rolling ◽  
Boiler Steel ◽  
Rolling Moment ◽  
Tools Wear

In continuous tube rolling process, it has an obvious influence on the stability of rolling process, tools wear and the quality of rolled hollow tube that configuration of roll rotational speed per stand. In this paper, various roll working diameters per stand are determined by velocity integral method (VIT) and FEM respectively, and two roll rotational speed schedules are obtained correspondingly based on 133 main pass sequence of 89mm 6-stand semi-floating mandrel mill. With the aid of commercial FE code MSC.SuperForm, the high pressure boiler steel tube continuous rolling process of a typical hollow tube specification 133.0×5.2mm are simulated, and force parameters, transverse wall thickness precision, outline dimension and real roundness of rolled hollow tube and clearance between the mandrel and rolled hollow tube are analyzed and compared on the condition of two different roll rotational speed schedules, which provides scientific basis for configuring reasonable roll rotational speed per stand in pass design and optimization. Analysis results indicate that roll working diameter obtained per stand is smaller and roll rotational speed configured is higher correspondingly using FEM compared to VIT. Using FEM, there exist front and back tensions between stands and maximal rolling force, rolling moment and mandrel axial force decrease 10% or so in continuous tube rolling process, and outline dimension and real roundness of rolled hollow tube is better. However, transverse wall thickness of rolled hollow tube at the bottom of groove is pulled thin slightly, and clearance between the mandrel and rolled hollow tube is less than normal.

Analysis of Transverse Wall Thickness Precision of Steel Tube Rolled by Semi-Floating Mandrel Mill

2010 ◽  
Vol 97-101 ◽  
pp. 3097-3103 ◽  
Author(s):  
Yuan De Yin ◽  
Sheng Zhi Li ◽  
Jie Xu ◽  
Yang Hua Li ◽  
Gong Ming Long ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Rolling Process ◽  
Steel Tube ◽  
Distribution Characteristic ◽  
Transverse Wall ◽  
Analysis Software ◽  
Continuous Rolling ◽  
Boiler Steel ◽  
Element Analysis ◽  
Simulation Results

With the aid of commercial finite element analysis software MSC. Superform, the high pressure boiler steel tube continuous rolling process with 6-stand semi-floating mandrel is simulated, and the distribution characteristic of transverse wall thickness is analyzed. It indicates that it presents “M” shape that the distribution of transverse wall thickness of hollow tube along one-fourth groove periphery. Transverse wall thicknesses have low values at the top, the bottom and sidewall 45 degree or so of groove, and they have high values at the sidewall 23 degree and 67 degree or so of groove. Then the improved measure is put forward on the basis of analyzing the causes responsible for transverse wall thickness. By the comparison of the simulation results, they have been improved obviously that transverse wall thickness precision and real roundness of rolled hollow tube using the improved measure.

Influence of Roll Speed Schedule on Transverse Wall Thickness Evenness of Shell Elongated by Mandrel Mill

2010 ◽  
Vol 654-656 ◽  
pp. 1311-1314 ◽  
Author(s):  
Sheng Zhi Li ◽  
Zhi Chao Zhang ◽  
Hai Yan Bao ◽  
Zhi Yang Zhou
Keyword(s):  
Wall Thickness ◽  
Rolling Process ◽  
Steel Tube ◽  
Transverse Wall ◽  
Data Reliability ◽  
Continuous Rolling ◽  
Roll Speed ◽  
Seamless Steel Tube ◽  
The Relationship ◽  
Seamless Steel

The seamless steel tube continuous rolling process with 8-stand full-floating mandrel is simulated with the aid of commercial FE code MSC. SuperForm. The relationship is analyzed between the distribution of the transverse wall-thickness and the speed schedule of the rollers. The result shows that the transverse evenness of the wall thickness of the tubes can be enhanced by optimizing the speed schedule. Furthermore, by adopting meliorated method to measure the wall-thickness of the shell, the error is reduced while data reliability is increased. When using the existing equipments (mandrel mill), it is an effective way to improve the transverse wall-thickness accuracy of the shell tube by adjusting the speed schedule. Compared with present roll speed schedule, the transverse wall-thickness accuracy can be increased by 10% for the rolling of elongated shell with 152.5mm in OD and 6mm in wall thickness tube under the 3# speed schedule put forward in this paper.

Analysis of Metal Flow and Deformation Features during Continuous Tube Rolling Process with Mandrel Mill

2011 ◽  
Vol 189-193 ◽  
pp. 2376-2381
Author(s):  
Yuan De Yin ◽  
Sheng Zhi Li ◽  
Yong Lin Kang ◽  
Lan Wei Hu
Keyword(s):  
Wall Thickness ◽  
Deformation Zone ◽  
Early Stage ◽  
Metal Flow ◽  
Equivalent Plastic Strain ◽  
Rolling Process ◽  
Lateral Spread ◽  
Thickness Reduction ◽  
Continuous Rolling ◽  
Stress Strain

With the aid of commercial FE code MSC.SuperForm, the structural steel tube continuous rolling process of a typical hollow tube specification 152.5×12.5mm is simulated based on Bao Steel 152.5 main pass sequence of 140mm 8-stand mandrel mill, and the distribution characteristics of stress/strain, outline lateral spread, temperature changes of workpiece in continuous rolling process and distribution of stress/strain, friction of workpiece in deformation zone are analyzed. Analysis results indicate that deformation of workpiece along the width of the groove, especially at the top and the bottom of the groove is highly inhomogeneous due to the unequal draught and the longitudinal stress of special position (the top and the bottom of the groove) of workpiece is always an alternate state, in a tensile-compressive-tensile manner, and has a distinct rule. In the first stand, outline dimension of workpiece gradually increases during reducing process and early stage of wall thickness reduction, but it gradually decreases during middle-late stage of wall thickness reduction and tends towards stability at last. It is inhomogeneous that distribution of unit compressive stress and longitudinal strain of workpiece in deformation zone, and contact stress and total equivalent plastic strain are maximal in inner surface of workpiece contacting with mandrel. Temperature difference between the outer and the inner surfaces of workpiece is obvious.

Application of Mass Scaling Technology in Steel Tube Rolling by Finite Element Simulation

2014 ◽  
Vol 887-888 ◽  
pp. 1139-1142
Author(s):  
Ning Pang ◽  
Zhi Yi Zhao
Keyword(s):  
Finite Element ◽  
Rolling Force ◽  
Element Model ◽  
Rolling Process ◽  
Steel Tube ◽  
Scaling Factor ◽  
Tube Rolling ◽  
Mass Scaling ◽  
Element Simulation ◽  
Operation Platform

Based on Abaqus/Explicit operation platform, a finite element model of Yantai Baosteel Φ460mm PQF mill was established to study the mass scaling factors influence of the rolling process. The experimental results show that mass scaling factor has smaller impact on the temperature. Distortion of rolling force and Mises stress gradually occurs with the increase of mass scaling factor. Under the premise of ensuring the calculation accuracy, a best mass scaling factor is found to improve the computational efficiency of the model.

Effect of Drive Roll Rotation Speed on Ring Rolling Process

2011 ◽  
Vol 189-193 ◽  
pp. 2586-2592
Author(s):  
Jie Zhou ◽  
Xiao Tao Gong ◽  
Xiao Bing Yang ◽  
Wu Jiao Xu
Keyword(s):  
Rotation Speed ◽  
Rolling Force ◽  
Metal Flow ◽  
Equivalent Plastic Strain ◽  
Rolling Process ◽  
Ring Rolling ◽  
Rolled Ring ◽  
Rolling Torque ◽  
Ring Rolling Process ◽  
Drive Roll

Based on the platform ABAQUS, 3-D FEA model for ring rolling has been constructed to investigate the effect of drive roll rotation speed on the metal flow in the ring rolling process. It can be seen clearly that the axial metal flow in the outside diameter of the rolled ring increases with the increasing of drive roll rotation speed and with the decreasing of the feeding magnitude per revolution , which causes the increasing of fishtail coefficient FT and maximum spread coefficient and in turn makes the quality deterioration of end-plane in the rolled ring. The rolling force and rolling torque necessary to execute the rolling process are reduced when the drive roll rotation speed is elevated, which results in the lower requirement for the characteristic of force and energy in the rolling machine. Besides that, average equivalent plastic strain PEEQ also increases, which indicates the enhancement of plastic deformation and is beneficial to the improvement of the mechanical property of the formed ring. But one point that we should pay attention is that uneven deformation and possibility of the inner defects in the rolled ring might be increased with the increasing of the drive roll rotation speed.

Research on Design Method of Polygonal Roll Pass for Stretch Reduced Seamless Tubes

2010 ◽  
Vol 654-656 ◽  
pp. 1614-1617 ◽  
Author(s):  
Sheng Zhi Li ◽  
Hai Yan Bao ◽  
Zhi Chao Zhang ◽  
Yang Hua Li ◽  
Gong Ming Long
Keyword(s):  
Wall Thickness ◽  
Design Method ◽  
Element Model ◽  
Rolling Process ◽  
Contact Length ◽  
Transverse Wall ◽  
Roll Pass ◽  
Steel Tubes ◽  
Pass System ◽  
Lateral Curvature

the aid of commercially available software MSC.SuperForm, a 3-D finite element model has been established to simulate the rolling process of steel tubes on the stretch reducing mill (SRM) with group centralized differential drive in certain factories. A special effort was made to analyze the fluctuation of transverse wall thickness uniformity. It was found that the wall thickness of each stand was accumulated in the original pass 50°~60° along the circumferential direction, which caused the formation of the inner hexagon defects and worsen. In view of this, this paper proposes a modified roll pass design method which uses the interactive technology of CAD graph curve and MATLAB equation. By means of decreasing the lateral curvature of roll pass contour curve to enlarge the contact length between the tube and groove, also the rolling process using the new pass system were simulated and analyzed. The results indicate that the design of such polygonal roll pass can be effective in improving the inner hexagon defects.

Numerical Simulation on Rolling Process of Medium Plate

2012 ◽  
Vol 602-604 ◽  
pp. 1864-1868 ◽  
Author(s):  
Lan Wei Hu ◽  
Xia Jin ◽  
Lei Shi ◽  
Sheng Zhi Li
Keyword(s):  
Contact Stress ◽  
Hot Rolling ◽  
Strain Field ◽  
Rolling Force ◽  
Metal Flow ◽  
Rolling Process ◽  
Slab Thickness ◽  
Actual Process ◽  
Hot Rolling Process ◽  
Rolling Efficiency

A 3-D thermal-mechanical model was built to simulate the hot rolling process of medium plate, with the aid of nonlinear commercial FE code MSC.SuperForm on a company's actual process parameters. The hot rolling process of single-pass which slab thickness is 180mm was simulated, and the influence of pass reduction on metal flow, stress-strain field, contact stress and rolling force were researched. The study revealed that pass reduction should be at least 20% by increase depress in pass in addition to rolling efficiency. As that, rolling efficiency be increased, roll contact stress be brought down, and its service life be prolonged. And metal plastic strain enhanced, metal flow increased, but its strain field non-uniformly distributed, metal flow and plastic deformation would be strengthen by increase pass reduction, and the lateral broadening in the head is bigger than that in the tail.

SIMULATION OF MULTI-PASS HOT ROLLING BY A MIXED ANALYTICAL-NUMERICAL METHOD

2011 ◽  
Vol 03 (03) ◽  
pp. 469-489 ◽  
Author(s):  
JINLING ZHANG ◽  
ZHENSHAN CUI
Keyword(s):  
Mathematical Model ◽  
Flow Stress ◽  
Strain Rate ◽  
Numerical Method ◽  
Hot Rolling ◽  
High Efficiency ◽  
Rolling Force ◽  
Metal Flow ◽  
Fem Simulation ◽  
Rolling Process

A mathematical model integrating analytical method with numerical method was established to simulate the multi-pass plate hot rolling process, predicting its strain, strain rate, stress and temperature. Firstly, a temperature analytical model was derived through series function solution, the coefficients in which for successive processes were smoothly transformed from the former process to the latter. Therefore, the continuous computation of temperature for multi-operation and multi-pass was accomplished. Secondly, kinematically-admissible velocity function was developed in Eulerian coordinate system according to the principle of volume constancy and characteristics of metal flow during rolling with undetermined coefficients — which were eventually solved by Markov variational principle. Thirdly, strain rate was calculated through geometric equations and the difference-equations for solving strain and a subsequent recurrent solution were established. Fourthly, rolling force was calculated on the base of Orowan equilibrium equation, considering the contribution to flow stress of strain, strain rate and temperature, rather than taking the flow stress as a constant. Consequently, the thermo-mechanics and deformation variables are iteratively solved. This model was employed in the simulation of an industrial seven-pass plate hot rolling schedule. The comparisons of calculated results with the measured ones and the FEM simulation results indicate that this mathematical model is able to reasonably represent the evolutions of various variables during hot rolling so it can be used in the analysis of practical rolling. Above all, the greatest advantage of the presented is the high efficiency. It costs only 12 seconds to simulate a seven-pass schedule, more efficient than any other numerical methods.

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