Formation Condition of Scale Layer on Work Roll in Hot Steel Rolling

2012 ◽  
Author(s):  
Akira Azushima ◽  
Kento Nakazawa
Keyword(s):  
Velocity Ratio ◽  
Work Roll ◽  
Rolling Reduction ◽  
Formation Condition ◽  
Roll Surface ◽  
Steel Rolling ◽  
Sheet Rolling ◽  
Scale Thickness ◽  
Scale Layer ◽  
Formation Conditions

It is well known that scale layer on work roll forms in hot sheet rolling of steel and scale layer on work roll plays an important role for hot rolling process. The formation conditions of scale layer on work roll are slightly known qualitatively and are hardly understood quantitatively. In order to investigate quantitatively the conditions of scale formation, three steels with different Si content are used and the slip rolling is carried out at a constant roll speed changing the scale thickness of steel workpiece and the reduction. The formation conditions of scale layer on work roll are examined quantitatively by observation of work roll surface after slip rolling. The experiments are carried out at constant rolling conditions of a velocity ratio of 20, a rolling speed of 50 m/min and a furnace temperature of 800 °C, changing the rolling reductions of 0.3, 0.5 and 1.0 mm and scale thickness of workpiece. The colza oil is used as base oil. The emulsion concentration is 3.0%. The emulsion temperature is controlled at 40 °C. Scale layer on work roll forms easily with increasing rolling reduction and decreasing scale thickness of workpiece for three steels A, B and C. In order to estimate quantitatively the formation condition of scale layer on work roll, parameter α which is given by a ratio of the rolling reduction to scale thickness of workpiece is proposed. Scale layer on work roll forms when values of parameter α become same for each steels. Values of parameter α become larger in order of steels A, B and C and it can be understood that scale layer on work roll forms easily in order of steels A, B and C. When FeO layer in scale of the steel surface adheres on work roll surface, it is expected that scale layer on work roll forms easily and strongly by transformation from FeO to Fe3O4, considering that the chemical composition of scale layer on work roll is Fe3O4.

A Study on Corrosion Wear of Cold Rolling Work Roll

2013 ◽  
Vol 871 ◽  
pp. 152-158
Author(s):  
Wei Hua Sun ◽  
Hong Chun Li ◽  
Ahn Kiet Tieu
Keyword(s):  
Cold Rolling ◽  
Corrosive Wear ◽  
Work Roll ◽  
Rolling Process ◽  
Corrosion Wear ◽  
Roll Surface ◽  
Steel Rolling ◽  
Conductive Medium ◽  
Materials Used ◽  
Work Rolls

The MMS-2B wear machine was used to study abrasion wear of work rolls in cold rolling by simulating emulsion cooling during the cold rolling process. The work roll materials used were 4%Cr, same as those in industrial production. The surface SEM scanning photographs were taken every 30 minutes until the friction experiment finished, and erosive appearance of emulsion on the work roll surface could be seen in the photos. The corrosive wear of the work roll surface is discussed. Findings show that the main causes of stress corrosion and pitting corrosion are uneven microstructure on the work roll surface and a large number of dislocation accumulations, which form microscopic cells. Water in steel rolling emulsion is the main conductive medium of electrochemistry reaction, and this intensifies the corrosive wear.

scholarly journals Influence of Work Roll Surface Oxide Scale on Interface Thermal Transfer

2018 ◽  
Vol 104 (12) ◽  
pp. 735-741
Author(s):  
Shohei Fujiwara ◽  
Eiji Abe ◽  
Nobuki Yukawa
Keyword(s):  
Oxide Scale ◽  
Work Roll ◽  
Surface Oxide ◽  
Roll Surface ◽  
Thermal Transfer

scholarly journals Eco-Friendly Water-Based Nanolubricants for Industrial-Scale Hot Steel Rolling

Lubricants ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 96
Author(s):  
Hui Wu ◽  
Hamidreza Kamali ◽  
Mingshuai Huo ◽  
Fei Lin ◽  
Shuiquan Huang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Oxide Scale ◽  
Rolling Force ◽  
Pure Water ◽  
Surface Hardness ◽  
Industrial Scale ◽  
Steel Rolling ◽  
Scale Thickness ◽  
Lubrication Performance ◽  
Water Based

Eco-friendly and low-cost water-based nanolubricants containing rutile TiO2 nanoparticles (NPs) were developed for accelerating their applications in industrial-scale hot steel rolling. The lubrication performance of developed nanolubricants was evaluated in a 2-high Hille 100 experimental rolling mill at a rolling temperature of 850 °C in comparison to that of pure water. The results indicate that the use of nanolubricant enables one to decrease the rolling force, reduce the surface roughness and the oxide scale thickness, and enhance the surface hardness. In particular, the nanolubricant consisting of 4 wt % TiO2, 10 wt % glycerol, 0.2 wt % sodium dodecyl benzene sulfonate (SDBS) and 1 wt % Snailcool exhibits the best lubrication performance by lowering the rolling force, surface roughness and oxide scale thickness by up to 8.1%, 53.7% and 50%, respectively. The surface hardness is increased by 4.4%. The corresponding lubrication mechanisms are attributed to its superior wettability and thermal conductivity associated with the synergistic effect of rolling, mending and laminae forming that are contributed by TiO2 NPs.

scholarly journals Simulation of Thermal Stress and Fatigue Life Prediction of High Speed Steel Work Roll during Hot Rolling Considering the Initial Residual Stress

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 966 ◽  
Author(s):  
Kejun Hu ◽  
Fuxian Zhu ◽  
Jufang Chen ◽  
Nao-Aki Noda ◽  
Wenqin Han ◽  
...  
Keyword(s):  
Residual Stress ◽  
Thermal Stress ◽  
Fatigue Life ◽  
Hot Rolling ◽  
Work Roll ◽  
Roll Surface ◽  
Initial Residual Stress ◽  
Thermal Fatigue Life ◽  
Cooling Conditions ◽  
Roll Temperature

Considerable residual stress is produced during heat treatment. Compressive residual stress at the shell is conductive to improving the thermal fatigue life of a work roll, while tensile stress in the core could cause thermal breakage. In hot rolling, thermal stress occurs under the heating-cooling cycles over the roll surface due to the contact with the hot strip and water spray cooling. The combination of thermal stress and residual stress remarkably influences the life of a work roll. In this paper, finite element method (FEM) simulation of hot rolling is performed by treating the residual stress as the initial stress. Afterwards, the effects of the initial roll temperature and cooling conditions on thermal stress considering the initial residual stress are discussed. Lastly, the thermal fatigue life of a work roll is estimated based on the strain life model. The higher initial roll temperature causes a higher temperature but a lower compressive thermal stress at the roll surface. The surface temperature and compressive stress increase significantly in the insufficient cooling conditions, as well as the center tensile stress. The calculation of the fatigue life of a work roll based on the universal slopes model according to the 10% rule and 20% rule is reasonable compared with experimental results.

DYNAMIC CHARACTERISTICS OF SHEET ROLLING INSTABILITY

2002 ◽  
Vol 02 (03) ◽  
pp. 375-394 ◽  
Author(s):  
Y.-J. LIN ◽  
C. S. SUH ◽  
S. T. NOAH
Keyword(s):  
Plastic Deformation ◽  
Dynamic Instability ◽  
Dominant Role ◽  
Physical Phenomenon ◽  
Spectral Characteristics ◽  
Work Roll ◽  
Rolled Strip ◽  
Sheet Rolling ◽  
Spectral Components ◽  
Work Rolls

Dynamic rolling instability known as fifth-octave chatter is studied using a nonlinear model developed to describe the responses of work rolls subjected to the exertion of sheet forces of various spectral characteristics. The model enables the dynamic instability of sheet rolling to be correlated with work roll stiffness, rolling speed, inter-stand tension, roll-bite entry and exit thickness, and the sheet force resulted from the interactive action of the work roll with the plastic deformation of the rolled strip. It is found that roll-bit elastic-plastic deformation sheet force is nonlinearly coupled with the rollstack stiffness and also plays a dominant role in affecting rolling instability. In addition, whenever the frequency spectrum of the normal sheet forces containing spectral components that match the fundamental modes of the roll stand, resonance-like beating would occur. This highly linear physical phenomenon, which is accompanied by large vibration amplitudes in the active work rolls, is recognized as chatter. Although many different dynamic modes of instability including mode excitation and beating are induced in response to sheet forces of nonlinear and non-stationary in nature, however, the rolling system never responds chaotically.

scholarly journals Skin Pass Rolling of High Manganese Steels

2016 ◽  
Vol 854 ◽  
pp. 93-98
Author(s):  
Kai Köhler ◽  
Norbert Kwiaton ◽  
Martin Bretschneider
Keyword(s):  
Surface Texture ◽  
Rolling Force ◽  
Work Roll ◽  
Major Influence ◽  
Roll Surface ◽  
High Manganese ◽  
Steel Sheets ◽  
Skin Pass ◽  
Texture Parameters ◽  
Work Rolls

Applying a specific roughness on steel sheets, to ensure paintability and sufficient lubrication, is a crucial point for the metal forming processes. Due to the strength of high manganese HSD® steels (X70MnAlSi 15-2.5-2.5), special actions are necessary to obtain the required roughness. At Salzgitter Mannesmann Forschung GmbH skin-pass rolling experiments on high manganese HSD® steels with different PRETEX® textured work-rolls were performed to investigate the influence of roll-surface-texture and skin-pass rolling force on the roughness transfer. The roughness and texture parameters of the steel sheets and roll surfaces were determined using optical confocal microscopy measurements. It is clearly shown that the work-roll surface texture has a major influence on the roughness transfer from work-rolls to steel sheet surfaces.

scholarly journals Eco-friendly Water-based Nanolubricants for Industrial-scale Hot Steel Rolling

2020 ◽  
Author(s):  
Hui Wu ◽  
Hamidreza Kamali ◽  
Mingshuai Huo ◽  
Fei Lin ◽  
Shuiquan Huang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Oxide Scale ◽  
Rolling Force ◽  
Pure Water ◽  
Surface Hardness ◽  
Industrial Scale ◽  
Steel Rolling ◽  
Scale Thickness ◽  
Lubrication Performance ◽  
Water Based

Eco-friendly and low-cost water-based nanolubricants containing rutile TiO2 nanoparticles (NPs) were developed for accelerating their applications in industrial-scale hot steel rolling. The lubrication performance of developed nanolubricants was evaluated in a 2-high Hille 100 experimental rolling mill at a rolling temperature of 850 ℃ in comparison to that of pure water. The results indicate that the use of nanolubricant enables to decrease the rolling force, reduce the surface roughness and the oxide scale thickness, and enhance the surface hardness. In particular, the nanolubricant consisting of 4 wt% TiO2, 10 wt% glycerol, 0.2 wt% sodium dodecyl benzene sulfonate (SDBS) and 1 wt% Snailcool exhibits the best lubrication performance by lowering the rolling force, surface roughness and oxide scale thickness up to 8.1%, 53.7% and 50%, respectively. The surface hardness is increased by 4.4%. The corresponding lubrication mechanisms are attributed to its superior wettability and thermal conductivity associated with the synergistic effect of rolling, mending and laminae forming that are contributed by TiO2 NPs.

Stochastic Method to Predict Effects of Roll Grinding Deviations on Sheet Flatness in Cold Rolling

2021 ◽  
pp. 1-34
Author(s):  
Feng Zhang ◽  
Arif S Malik
Keyword(s):  
Random Field ◽  
Contact Region ◽  
Measurement Data ◽  
Work Roll ◽  
Rolling Process ◽  
Rolled Sheet ◽  
Field Problem ◽  
Sheet Rolling ◽  
Roll Axis ◽  
Work Rolls

Abstract Industrial measurements of the diameter profiles of work-rolls used in cold sheet rolling are applied with a stochastic roll-stack model to better understand how residual error from the roll grinding process affects the rolled sheet flatness quality. Roll diameter measurements taken via a non-contact, optical device on new, warm, and worn work-rolls show that the diameter deviations vary along the roll lengths, across roll samples, and at different operational states, suggesting a multi-dimensional random field problem. Studies are conducted for a 4-high rolling mill with 301 stainless steel sheet to investigate the reliability in achieving target flatness considering the work-roll diameter random field. Also investigated is the sensitivity of the flatness reliability to roll diameter deviations at different locations along the roll lengths, and for the three operational states (newly machined, warm, and worn following several passes). The results lead to several key findings. Foremost, it is shown that an assumption of statistical independence among the residual grinding errors at different roll axis locations is improper. Further, it is demonstrated that, for the measured grinding error correlation patterns, the roll diameter deviations external to the roll/sheet contact region play an important role in contributing to flatness defects within the sheet, and that these influences vary according to the roll operational state (new, warm, worn). The presented stochastic model and applied measurement data thus provide for a new understanding into how roll grinding performance influences dimensional quality in the sheet rolling process.

Tempering effect on residual stress in bimetallic roll

2021 ◽  
pp. 2140044
Author(s):  
Nao-Aki Noda ◽  
Mohd Radzi Aridi ◽  
Yoshikazu Sano
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Maximum Stress ◽  
Work Roll ◽  
Nonuniform Heating ◽  
Roll Surface ◽  
Uniform Heating ◽  
Heating Treatment ◽  
Quenching And Tempering

In this study, tempering effect on the residual stress is studied after uniform heating–quenching and nonuniform heating–quenching for bimetallic work roll. Results for uniform heating treatment showed that the maximum stress at the center decreases by 68% from 396 MPa to 126 MPa after the first and second tempering. Results for nonuniform heating treatment showed that the maximum stress at the center decreases by 47% from 309 MPa to 165 MPa after the first and second tempering. It may be concluded that nonuniform heating–quenching and tempering are useful for reducing the central tensile stress preventing cracks at the roll surface.

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