Tribology in Sheet Rolling Technology (eBook)

Dr. Akira Azushima is a Professor Emeritus at Yokohama National University in Japan.

1. Fundamental of Tribology1.1  Friction1.1.1 Friction in history1.1.2 Contact model between surfaces with surface roughness1.1.3 Junction growth and real contact area1.1.4 Effect of surface film1.1.5 Plowing term in friction1.2  Lubrication1.2.1 Lubrication in history1.2.2 Stribeck curve1.2.3 Hydrodynamic lubrication1.2.3.1   Reynolds equation1.2.3.2   Plane bearing1.2.3.3   Journal bearing1.2.3.4   Rolling bearing1.2.3.5   Pressure distribution of journal and rolling bearings1.2.3.6   Elasto-hydrodynamic lubrication (EHL)1.2.3.7   Effect of viscosity of lubricant1.2.3.8   Elastic deformation1.2.4 Boundary lubrication1.2.4.1   Boundary lubrication model1.2.4.2   Boundary film1.2.5 Mixed lubrication1.3  Wear1.3.1 Adhesive wear1.3.2 Abrasive wearReferences2. Tribology in metalforming2.1  Characteristics of tribology in metalforming2.1.1 Lubrication regime2.1.2 Contact pressure2.1.3 Interfacial temperature2.1.4 Sliding speed2.1.5 Introducing and entrapping lubricant2.1.6 Virgin surface2.2  Micro-contact between tool and workpiece2.2.1   Hydrostatic pressure2.2.2   Entrapped lubricant in upsetting 2.2.3   Roughening of lubricated surface by thick film2.2.4   Free surface roughening2.2.5   Asperity deformation in upsetting test and indentation test2.2.5.1   Dry condition2.2.5.2   Lubricated condition2.2.6   Micro-plasto-hydrodynamic lubrication (Micro-PHL)2.2.7   Asperity deformation in sheet metal forming2.2.8   Oil pocket behavior on edge surface of cylinder billet in upsetting process2.3  Lubrication mechanism and frictional stress2.3.1 Lubrication mechanism2.3.2 Friction stress2.3.2.1   Plasto-hydrodynamic lubrication2.3.2.2   Boundary lubrication2.3.2.3   Micro-hydrodynamic lubrication2.3.2.4   Mixed lubrication2.4  Lubrication mechanism and surface appearance of workpiece2.4.1 Plasto-hydrodynamic lubrication2.4.2 Boundary lubrication2.4.3 Micro-plasto-hydrodynamic lubrication2.4.4 Mixed lubrication2.5  Oil film thickness at interface between and workpiece2.5.1 Oil film thickness in steady state metalforming process2.5.1.1   Constant viscosity2.5.1.2   Viscosity depending on pressure2.5.1.3   Viscosity depending on pressure and temperature 2.5.2 Oil film thickness in unsteady state metalforming process2.5.2.1   Upsetting at high compression speed2.5.2.2   Upsetting at low compression speed2.6  Interfacial temperature between tool and workpiece2.6.1 Interfacial temperature rise by friction energy2.6.2 Interfacial temperature rise by shear energy in hydrodynamic lubrication2.6.3 Comparison of results calculated with results measured by experiments in sheet drawing2.7  Seizure2.7.1 Seizure in machine element2.7.2 Seizure in metalforming2.8  Tribo-simulation in metalforming2.8.1 Relationship between tribological conditions and tribological results2.8.2 Tribo-simulatorReferences3. Fundamental of Rolling3.1  Mechanics of rolling3.2  Rolling theory3.2.1 Two dimensional homogenous theory for rolling3.2.2 Two dimensional in-homogenous theory for rolling3.3  Flow stress for rolling theory3.3.1 Flow stress in cold sheet rolling3.3.2 Flow stress in hot sheet rolling 3.4  Coefficient of friction for rolling theory3.5  Simulation test for coefficient of frictionReferences4. Tribology in Cold Sheet Rolling4.1 Coefficient of fricition4.1.1 Coefficient of friction in history4.1.2 Dependence of coefficient of friction from rolling theory4.1.2.1   Coefficient of friction in neat oils4.1.2.2   Coefficient of friction in emulsion oil4.1.3 Coefficient of friction measured by sliding-rolling type tribo-simulator 4.1.3.1   Evaluation of coefficient of friction measure4.1.3.2   Evaluation of additive in mineral base oil by coefficient of friction4.1.3.3   Evaluation of tallow base oil by coefficient of friction4.1.3.4   Evaluation of mixed rolling oil of mineral base oil tallow oil by coefficient of      friction4.2  Lubrication mechanism and rolling pressure4.2.1 Macro-plasto-hydrodynamic lubrication4.2.2 Boundary lubrication4.2.3 Micro-plasto-hydrodynamic lubrication4.2.4 Mixed lubrication4.2.4.1   Combination of hydrodynamic lubrication and boundary lubrication4.2.4.2   Combination of hydrostatic lubrication and boundary lubrication4.2.4.3   Combination of hydrodynamic lubrication, hydrostatic lubrication and boundary lubrication4.3  Inlet oil film thickness in cold sheet rolling with neat oil4.3.1 Calculation of inlet oil film thickness4.3.2 Measurement of inlet oil film thickness4.3.3 Inlet oil film thickness for workpiece with random surface roughness4.4  Surface appearance in cold sheet rolling with neat oil4.4.1 Surface appearance by rolling experiment4.4.1.1   Effect of rolling speed and reduction on surface appearance4.4.1.2   Effect of viscosity of lubricant on surface appearance4.4.1.3   Effect of surface roughnesses of roll and sheet4.4.2 Surface brightness of low carbon steel4.4.2.1   Surface brightness for roll and sheet with smooth surface4.4.2.2   Effect of roll surface on surface brightness4.4.2.3   Effect of surface roughness of sheet on surface brightness4.4.2.4   Relationship between surface brightness and inlet oil film thickness4.4.3 Estimation system for surface brightness of rolled sheet4.4.3.1   Outline of new estimation system4.4.3.2   Evaluation of estimation system in joint research4.4.3.3   Simulation method4.4.3.4   Simulation results4.4.3.5   Improvement of surface brightness4.5  Inlet oil film thickness in emulsion oil4.5.1 Emulsion lubrication in history4.5.2 Emulsion behavior in EHL contact4.5.3 Inlet oil film thickness in cold sheet rolling with emulsion oil4.5.3.1   Analysis of inlet oil film thickness by dynamic concentration model4.5.3.2   Calculated results of inlet oil film thickness4.5.3.3   Comparison of inlet oil film thickness calculated with that measured4.5.4 Discussion of inlet oil film thickness in O/W emulsion 4.5.5 New model for calculation of inlet oil film thickness in O/W emulsion4.6  Surface appearance of workpiece in emulsion oil4.6.1 Comparison of surface appearance in O/W emulsion oil with that in neat oil4.6.2 Effect of tribological conditions on surface appearance with emulsion oil4.6.2.1   Effect of emulsion property on surface brightness4.6.2.2   Effect of oil property on surface quality4.6.3 Surface brightness irregularity of stainless steel with O/W emulsion4.7  Interfacial temperature in cold sheet rolling4.7.1 Calculation of interfacial temperature in cold sheet rolling4.7.2 Temperature measurement of roll surface by thermocouple4.7.3 Temperature measurement of interface between roll and sheet by thermoelectric method4.8  Friction pick up (Heat streak)4.8.1 Friction pick up in history4.8.2 Simulation for friction pick up4.8.2.1   Evaluation of anti-seizure property of tallow oil4.8.2.2   Evaluation of anti-seizure property of commercial oils4.8.3 Development of commercial oil with high anti-seizure property4.8.4 Estimation of anti-seizure property in cold sheet tandem mill of stainless steel4.8.4.1   Evaluation of anti-seizure property by slip rolling type tribo-simulator4.8.4.2   Evaluation of anti-seizure property by normal rolling4.8.4.3   Estimation of mean interfacial temperature in tandem mill4.9  Cold rolling oil4.9.1 Cold rolling oil in history4.9.1.1   Emulsion particle4.9.1.2   Plating out4.9.2 Development of new rolling oil with high lubricity4.9.2.1   Experimental4.9.2.2   Results4.10 Cold roll4.10.1 Cold roll in history4.10.2 Evaluation of anti-seizure property of commercial rolls4.10.2.1   Experimental4.10.2.2   Results4.10.3 Development of roll with high anti-seizure property4.10.3.1   Experimental4.10.3.2   Results4.10.4 Verification of relationship between limitation reduction and carbide mean spacing4.10.5 Application of new developed roll to cold tandem mill4.10.6 Evaluation of surface treated rollsReferences5. Tribology in hot sheet rolling5.1  Tribology in hot sheet rolling in history5.1.1 Actual hot tandem mill5.1.2 Laboratory mill 5.1.2.1   Effect of lubricant on rolling load5.1.2.2   Effect of tribological factor5.2  Coefficient of friction5.2.1 Coefficient of friction in history5.2.2 Coefficient of friction measured by SRV testing machine5.2.3 Coefficient of friction measured by hot sliding-rolling type tribo-simulator developed newly5.2.3.1   Hot sliding-rolling type tribo-simulator5.2.3.2   Effect of surface roughness of roll on coefficient of friction5.3  Lubrication mechanism5.4  Friction model5.4.1 Emulsion concentration of c ＞ 1.0%5.4.2 Emulsion concentration of c ＜ 1.0%5.4.3 Effect of surface roughness of roll on coefficient of friction5.4.4 Effect of roll speed on coefficient of friction5.4.5 Confirmation of friction law5.5  Friction pick up5.5.1 Friction pick up in history5.5.2 Friction pick up of carbon steel with high strength5.6  Scale on workpiece surface5.6.1 Characteristics of scales5.6.2 Effect of scale thickness on coefficient of friction5.6.3 Effect of scale composition on coefficient of friction5.6.4 Effect of Si content on coefficient of friction5.7 Scale on roll surface 5.7.1 Scale on roll surface in history5.7.2 Formation condition of black scale layer5.7.2.1   Effect of sale thickness of sheet surface on formation condition5.7.2.2   Effect of composition of sheet on formation condition5.7.2.3   Effect of emulsion concentration on formation condition5.7.2.4   Effect of base oil and additive on formation condition5.8  Hot rolling lubricant5.8.1 Hot rolling lubricant in history5.8.2 Evaluation of hot rolling oil by hot sliding-rolling type tribo-simulator5.8.3 Development of hot rolling oil for stainless steel5.8.4 Development of rolling oil with hot rolling with large reduction5.8.4.1   Previous consideration5.8.4.2   Experiments and results5.9 Hot roll5.9.1 Hot roll in history5.9.2 Development of hot roll for hot rolling with high reduction5.9.2.1   Previous consideration5.9.2.2   ResultsReferences