Tribology in Sheet Rolling Technology
Akira Azushima
Contents
1 Fundamentals of Tribology 1
1.1 Friction 1
1.1.1 Friction in History 1
1.1.2 Contact Model Between Surfaces
with Surface Roughness 2
1.1.3 Junction Growth of Real Contact Area . 4
1.1.4 Effect of Surface Film . 5
1.1.5 Plowing Term in Friction . 6
1.2 Lubrication . 7
1.2.1 Lubrication in History . 7
1.2.2 Stribeck Curve . 8
1.2.3 Hydrodynamic Lubrication 9
1.2.4 Elastohydrodynamic Lubrication . 18
1.2.5 Boundary Lubrication . 19
1.2.6 Mixed Lubrication 23
1.3 Wear 24
1.3.1 Adhesive Wear 25
1.3.2 Abrasive Wear . 25
References . 26
2 Tribology in Metalforming 27
2.1 Characteristics of Tribology in Metalforming . 27
2.1.1 Lubrication Regime . 28
2.1.2 Contact Pressure . 29
2.1.3 Interfacial Temperature 30
2.1.4 Sliding Speed . 31
2.1.5 Introducing and Entrapping Lubricant 32
2.1.6 Virgin Surface . 34
2.2 Micro-contact Between Tool and Workpiece . 34
2.2.1 Hydrostatic Pressure 34
vii2.2.2 Entrapped Lubricant in Upsetting . 37
2.2.3 Roughening of Lubricated Surface
by Thick Film . 39
2.2.4 Free Surface Roughening . 42
2.2.5 Asperity Deformation in Upsetting Test
and Indentation Test 43
2.2.6 Micro-plastohydrodynamic Lubrication
(Micro-PHL) 47
2.2.7 Asperity Deformation in Sheet Metalforming 52
2.2.8 Oil Pocket Behavior on Edge Surface of Cylindrical
Billet in Upsetting Process 58
2.3 Lubrication Mechanism and Frictional Stress . 65
2.3.1 Lubrication Mechanism 65
2.3.2 Frictional Stress 66
2.4 Lubrication Mechanism and Surface Appearance
of Workpiece 71
2.4.1 Plastohydrodynamic Lubrication 71
2.4.2 Boundary Lubrication . 72
2.4.3 Micro-plastohydrodynamic Lubrication . 75
2.4.4 Mixed Lubrication 75
2.5 Oil Film Thickness at Interface Between Tool
and Workpiece . 76
2.5.1 Oil Film Thickness in Steady-State
Metalforming Process . 76
2.5.2 Oil Film Thickness in Unsteady-State
Metalforming Process . 80
2.6 Interfacial Temperature Between Tool and Workpiece 84
2.6.1 Interfacial Temperature Rise by Friction Energy 84
2.6.2 Interfacial Temperature Rise by Shear Energy in
Hydrodynamic Lubrication 88
2.6.3 Comparison of Results Calculated with Results
Measured by Experiments in Sheet Drawing . 88
2.7 Seizure 90
2.7.1 Seizure in Machine Element . 90
2.7.2 Seizure in Metalforming 91
2.8 Tribo-simulation in Metalforming . 93
2.8.1 Relationship Between Tribological Conditions
and Tribological Results 93
2.8.2 Tribo-simulator 95
2.8.3 Tribo-simulation Tests for New Tribo-simulator
in Metalforming 96
References . 98
viii Contents3 Fundamentals of Rolling 99
3.1 Mechanics of Rolling 99
3.2 Rolling Theory . 103
3.2.1 Two-Dimensional Homogenous Deformation
Theory for Rolling 103
3.2.2 Two-Dimensional Inhomogenous Deformation
Theory for Rolling 106
3.3 Flow Stress for Rolling Theory . 108
3.3.1 Flow Stress in Cold Sheet Rolling 108
3.3.2 Flow Stress in Hot Sheet Rolling . 111
3.4 Coefficient of Friction for Rolling Theory . 115
3.5 Simulation Test for Coefficient of Friction . 117
References . 120
4 Tribology in Cold Sheet Rolling 123
4.1 Coefficient of Friction 123
4.1.1 Coefficient of Friction in History . 123
4.1.2 Dependence of Coefficient of Friction
from Rolling Theory 125
4.1.3 Coefficient of Friction Measured by SlidingRolling-Type Tribo-Simulator Developed . 129
4.2 Lubrication Mechanism and Rolling Pressure . 139
4.2.1 Macro-plastohydrodynamic Lubrication 140
4.2.2 Boundary Lubrication . 141
4.2.3 Micro-plastohydrodynamic Lubrication . 141
4.2.4 Mixed Lubrication 142
4.3 Inlet Oil Film Thickness in Cold Sheet Rolling
with Neat Oil 144
4.3.1 Calculation of Inlet Oil Film Thickness . 144
4.3.2 Measurement of Inlet Oil Film Thickness . 147
4.3.3 Inlet Oil Film Thickness for Workpiece
with Random Surface Roughness . 150
4.4 Surface Appearance of Workpiece in Cold Sheet Rolling
with Neat Oil 157
4.4.1 Surface Appearance by Rolling Experiments . 157
4.4.2 Surface Brightness of Low Carbon Steel 162
4.4.3 Estimation System for Surface Brightness
of Rolled Sheet 169
4.5 Inlet Oil Film Thickness in Emulsion Oil 177
4.5.1 Emulsion Lubrication in History 177
4.5.2 Emulsion Behavior in EHL Contact . 181
4.5.3 Inlet Oil Film Thickness in Cold Sheet Rolling
with Emulsion Oil 184
4.5.4 Discussion of Inlet Oil Film Thickness
in O/W Emulsion . 189
4.5.5 New Model for Calculation of Inlet Oil Film Thickness
in O/W Emulsion . 191
Contents ix4.6 Surface Appearance of Workpiece in Cold Sheet Rolling
with Emulsion Oil 194
4.6.1 Comparison of Surface Appearance in O/W
Emulsion Oil with That in Neat Oil . 195
4.6.2 Effect of Tribological Conditions on Surface
Appearance with Emulsion Oil . 198
4.6.3 Surface Brightness Irregularity in Cold Sheet Rolling
of Stainless Steel with O/W Emulsion 201
4.7 Interfacial Temperature in Cold Sheet Rolling 204
4.7.1 Calculation of Interfacial Temperature
in Cold Sheet Rolling 204
4.7.2 Temperature Measurement of Roll Surface
by Thermocouple . 205
4.7.3 Temperature Measurement of Interface Between
Roll and Sheet by Thermoelectric Method . 208
4.8 Friction Pickup (Heat Streak) 213
4.8.1 Friction Pickup in History 213
4.8.2 Simulation for Friction Pickup . 215
4.8.3 Development of Commercial Oil with High
Antiseizure Property 220
4.8.4 Estimation of Antiseizure Property in Cold Sheet
Tandem Mill of Stainless Steel . 223
4.9 Cold Rolling Oil 228
4.9.1 Cold Rolling Oil in History . 228
4.9.2 Development of New Rolling Oil
with High Lubricity . 232
4.10 Cold Roll . 236
4.10.1 Cold Roll in History 236
4.10.2 Evaluation of Antiseizure Property
of Commercial Rolls 238
4.10.3 Development of Roll with High Antiseizure
Property . 241
4.10.4 Verification of Relationship Between Limitation
Reduction and Carbide Mean Spacing 246
4.10.5 Application of New Developed Roll
to Cold Tandem Mill 248
4.10.6 Evaluation of Surface-Treated Rolls . 251
References . 253
5 Tribology in Hot Sheet Rolling . 255
5.1 Tribology in Hot Sheet Rolling in History . 255
5.1.1 Actual Hot Tandem Mill . 255
5.1.2 Laboratory Mill 257
5.2 Coefficient of Friction 261
5.2.1 Coefficient of Friction in History . 261
x Contents5.2.2 Coefficient of Friction Measured by SRV Testing
Machine . 265
5.2.3 Coefficient of Friction Measured by Hot SlidingRolling-Type Tribo-Simulator Newly Developed . 268
5.3 Lubrication Mechanism 273
5.4 Friction Model . 276
5.4.1 Emulsion Concentrations of c > 1.0 % . 276
5.4.2 Emulsion Concentrations of c < 1.0 % . 276
5.4.3 Effect of Surface Roughness of Roll on Coefficient
of Friction 277
5.4.4 Effect of Roll Speed on Coefficient of Friction . 277
5.4.5 Confirmation of Friction Law 279
5.5 Friction Pickup . 281
5.5.1 Friction Pickup in History 281
5.5.2 Friction Pickup of Carbon Steel with High Strength 285
5.6 Scale on Workpiece Surface . 289
5.6.1 Characteristics of Scale 289
5.6.2 Effect of Scale Thickness on Coefficient
of Friction 290
5.6.3 Effect of Chemical Composition of Sheet
on Coefficient of Friction . 294
5.6.4 Effect of Si Content of Carbon Steel
on Coefficient of Friction . 297
5.7 Scale on Roll Surface 299
5.7.1 Scale on Roll Surface in History 300
5.7.2 Formation Condition of Black Scale Layer 303
5.8 Hot Rolling Lubricant 310
5.8.1 Hot Rolling Lubricant in History . 310
5.8.2 Evaluation of Hot Rolling Oil by Hot Sliding-Rolling
Type Tribo-Simulator . 312
5.8.3 Development of Hot Rolling Oil
for Stainless Steel 315
5.8.4 Development of Rolling Oil for Hot Rolling
with Large Reduction 317
5.9 Hot Roll 322
5.9.1 Hot Roll in History . 322
5.9.2 Development of Hot Roll for Hot Sheet Rolling
with High Reduction 326
References . 328
Index
كلمة سر فك الضغط : books-world.net
The Unzip Password : books-world.net
تحميل
يجب عليك التسجيل في الموقع لكي تتمكن من التحميل
تسجيل | تسجيل الدخول