A study of flatness defect in strip rolling occurred in tension unloading

2016 ◽  
Author(s):  
Sami Abdelkhalek ◽  
Hamid Zahrouni ◽  
Nicolas Legrand ◽  
Michel Potier-Ferry
Keyword(s):  
Strip Rolling ◽  
Flatness Defect

Modification of tundish design to improve quality of slabs, casted at CCM No. 4 of EVRAZ NTMK

2020 ◽  
Vol 76 (6) ◽  
pp. 559-563
Author(s):  
I. M. Zakharov ◽  
V. A. Smirnov ◽  
D. V. Sushnikov ◽  
A. G. Lyzhin ◽  
E. A. Lavrova ◽  
...  
Keyword(s):  
Basic Number ◽  
Metal Level ◽  
Surface Layers ◽  
Secondary Oxidation ◽  
Strip Rolling ◽  
Actual Distribution ◽  
Ultrasonic Control ◽  
Analysis Of Results ◽  
Water Simulation

A technology of continuous casting of steel has a large effect on its contamination. In particular, proper organization of metal flows in tundish and mold is very important. After completion a series of casting through a tundish and drop of metal level in it, it possible, that the slag flows from the surface layers of the tundish to capture the metal. An analysis of results of ultrasonic control of finished strip showed, that the basic number of the revealed defects was obtained during strip rolling out of the last slabs of the last heat in a series for a tundish. Metallographic studies determined, that the defects were located in the slab axis zone and filled by macro-inclusions of complex composition. To determine the actual distribution of metal flows, a water simulation of them was accomplished for the existing design of the EVRAZ NTMK tundish. It was determined, that at the drop of metal level in a tundish, a capture of slag from the metal reservoir and its transfer into the main bath of the tundish takes place due to whirligig flows. Following the weight metal consumption, the zone of slag inclusions distribution enlarges. Besides, denudation of the metal mirror in the metal reservoir takes place, resulted in metal secondary oxidation. Based on the results of the simulation, it was proposed to modify the design of the “turbostop”, which is installed in the metal reservoir of the tundish. Besides, it was proposed to remove the dividers installation in the tundish. It was noted, that the proposed steps enable to ensure a minimal level of rejections.

Microstructural Control in Thick-Walled Nb-Ti-V Microalloyed Linepipe Steels

2004 ◽  
Vol 467-470 ◽  
pp. 223-228
Author(s):  
K.M. Banks
Keyword(s):  
Grain Size ◽  
Laboratory Simulation ◽  
Microalloyed Steels ◽  
Processing Parameter ◽  
Strip Rolling ◽  
Bearing Steels ◽  
Simulation Results ◽  
Linepipe Steels ◽  
Ferrite Grain Size ◽  
Microstructural Control

Various microstructure models for Nb-bearing steels were tested under industrial strip rolling conditions to establish a relationship between grain size and toughness in Ti-Nb-V microalloyed steels. For similar Nb contents, microstructure models for Nb steels were found to adequately describe recrystallisation kinetics in more complex Ti-Nb-V steels. For thick-walled linepipe (11.6mm), a minimum of 0.04%Nb is required to achieve adequate toughness. Retained strain was the dominant processing parameter factor affecting ferrite grain size. The predicted minimum amount of retained strain after the last pass required for sufficient grain refinement concurred with laboratory simulation results. For the rolling schedules investigated, metadynamic recrystallisation was predicted to occur during roughing, whilst static recrystallisation was predominant during finishing.

Energy-force parameters of six-high stands in wide-strip rolling mills

2007 ◽  
Vol 2007 (1) ◽  
pp. 41-50 ◽  
Author(s):  
E. A. Garber ◽  
N. L. Bolobanova ◽  
A. I. Traino ◽  
E. V. Diligenskii
Keyword(s):  
Strip Rolling ◽  
Rolling Mills ◽  
Wide Strip

FEM Analysis of Profile Control Capability during Rolling in a 6-High CVC Cold Rolling Mill

2014 ◽  
Vol 988 ◽  
pp. 257-262 ◽  
Author(s):  
Ke Zhi Linghu ◽  
Zheng Yi Jiang ◽  
Fei Li ◽  
Jing Wei Zhao ◽  
Meng Yu ◽  
...  
Keyword(s):  
Cold Rolling ◽  
Rolling Mill ◽  
Rolling Force ◽  
Fem Analysis ◽  
Continuous Variable ◽  
Cold Rolling Mill ◽  
Strip Rolling ◽  
Roll Bending ◽  
Profile Control ◽  
Control Capability

A 3D elastic-plastic finite element method (FEM) model of cold strip rolling for 6-high continuous variable crown (CVC) rolling mill was developed. The rolling force distributions were obtained by the internal iteration processes. The calculated error has been significantly reduced by the developed model. the absolute error between the simulated results and the actual values is obtained to be less than 10μm, and relative error is less than 1%. The developed model is significant in investigating the profile control capability of the CVC cold rolling mill in terms of work roll bending, intermediate roll bending and intermediate roll shifting.

A fast rigid-plastic finite element method for online application in strip rolling

2010 ◽  
Vol 46 (12) ◽  
pp. 1146-1154 ◽  
Author(s):  
S.H. Zhang ◽  
G.L. Zhang ◽  
J.S. Liu ◽  
C.S. Li ◽  
R.B. Mei
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Strip Rolling ◽  
Rigid Plastic ◽  
Online Application ◽  
Element Method

X-ray thickness gauge for hot strip rolling mills

1948 ◽  
Vol 67 (5) ◽  
pp. 441-444 ◽  
Author(s):  
C. W. Clapp ◽  
R. V. Pohl
Keyword(s):  
Thickness Gauge ◽  
Hot Strip Rolling ◽  
Strip Rolling ◽  
Rolling Mills ◽  
X Ray ◽  
Hot Strip

Evaluation of Strip Rolling Directly from the Semi-Solid State

2006 ◽  
Vol 116-117 ◽  
pp. 433-436 ◽  
Author(s):  
Antonio de Pádua Lima Filho ◽  
Márcio Iuji Yamasaki
Keyword(s):  
Solid State ◽  
Cooling System ◽  
Solid Alloy ◽  
Strip Rolling ◽  
Tin Alloys ◽  
Cooling Slope ◽  
Quality Issue ◽  
Lower Roller ◽  
Semi Solid ◽  
Strip Quality

The aim of this work is to study the solidification conditions necessary to produce good quality/low defect metal alloy strip when thixorolling directly from the semi-solid state. To facilitate the study lead/tin alloys were chosen for their relatively low operating temperature. The objective is to extrapolate these findings to the higher temperature aluminium alloys. Three alloys (70%Pb- 30%Sn, 60%Pb-40%Sn, 50%Pb-50%wtSn) were used particularly to study the influence of the solidification interval. The equipment consists of a two roll mill arranged as an upper and lower roller, where both rollers are driven at a controlled speed. The lower roller is fed with semi solid alloy through a ceramic nozzle attached to the lower end of a cooling slope. Several types of nozzle and their position at the roller were tested. This produced different solidifications and consequently different finished strip. The alloys were first cast and then poured onto the cooling slope through a tundish in order to create a continuous laminar flow of slurry and uniformity of metal strip quality. The pouring was tested at different positions along the slope. The cooling slope was coated with colloidal graphite to promote a smooth slurry flow and avoid the problem of adherence and premature solidification. The metallic slurry not only cools along the slope but is also initially super-cooled to a mush by the lower roller whilst at room temperatures, thus enabling thixorolling. It was also found that the nozzle position could be adjusted to enable the upper roller to also contribute to the solidification of the metallic slurry. However the rollers and the cooling slope naturally heat up. Temperature distribution in these zones was analysed by means of three thermocouples positioned along the cooling slope and a fourth in the base of the semi solid pool within the nozzle. The objective being to design an optimum pouring and cooling system. The formed strip was cooled down to room temperature with a shower of water. Microstructures of the thixorolling process were analysed. The differences in solidification conditions resulted in differing qualities of finished strip and corresponding defect types, all of which are a serious quality issue for the rolled product.

scholarly journals Analysis of Roll Gap Heat Transfers in Hot Steel Strip Rolling through Roll Temperature Sensors and Heat Transfer Models

2012 ◽  
Vol 504-506 ◽  
pp. 1043-1048 ◽  
Author(s):  
Nicolas Legrand ◽  
Nathalie Labbe ◽  
Daniel Weisz-Patrault ◽  
Alain Ehrlacher ◽  
Tomasz Luks ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Steel Strip ◽  
Temperature Sensors ◽  
Strip Rolling ◽  
Strip Surface ◽  
Roll Temperature ◽  
Heat Transfers ◽  
Roll Gap ◽  
Roll Bite ◽  
Transfer Models

This paper presents an analysis of roll bite heat transfers during hot steel strip rolling. Two types of temperature sensors (drilled sensor /slot sensor) implemented near roll surface and heat transfer models are used to identify in the roll bite interfacial heat flux, temperature and Heat Transfer Coefficient HTCroll-bite during pilot rolling tests. It is shown that: - the slot type sensor is much more efficient than the drilled type sensor to capture correctly fast roll temperature changes in the bite during hot rolling but life’s duration of the slot sensor is shorter. - average HTCroll-bite, identified with roll sensors temperature signals is within the range 15-26 kW/m2/K: the higher the strip reduction is, the higher the HTCroll-bite is. - scale thickness at strip surface tends to decrease heat transfers from strip to roll in the roll bite. - HTCroll-bite appears not uniform along the roll-strip contact, in contrast to usual assumptions made in existing models - Heat dissipated by friction at roll-strip interface and its partitioning through roll and strip respectively seems over-estimated in the existing thermal roll gap model [1]. Modeling of interfacial friction heat dissipation should be reviewed and verified. The above results show the interest of roll temperature sensors to determine accurately roll bite heat transfers and evaluate more precisely the corresponding roll thermal fatigue degradation.

Study on Surface Roughness Muring Metal Manufacturing Process

2011 ◽  
Vol 325 ◽  
pp. 731-736
Author(s):  
Zheng Yi Jiang ◽  
Shu Jun Wang ◽  
Dong Bin Wei ◽  
Hei Jie Li ◽  
Hai Bo Xie ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Crack Nucleation ◽  
Metal Plate ◽  
Experimental Result ◽  
Strip Rolling ◽  
Surface Asperity ◽  
Asperity Flattening ◽  
Cold Strip Rolling ◽  
Effect Of Surface ◽  
Good Agreement

In the paper, a crystal plasticity finite element method (CPFEM) model was developed based on ABAQUS to analyse the surface roughness transfer during metal manufacturing. The simulation result shows a good agreement with the experimental result in the flattening of surface asperity, and the surface roughness decreases significantly with an increase of reduction with considering friction effect. Lubrication can delay surface asperity flattening. The effect of surface roughness on produced metal defect (crack) was also studied, and the surface roughness affects the crack initiation significantly in cold strip rolling. In addition, the surface roughness variation along the metal plate width contributes to stress distribution and then inhibition of crack nucleation.

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