The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
I J Freshwater - One of the best experts on this subject based on the ideXlab platform.
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simplified theories of flat Rolling i the calculation of Roll Pressure Roll force and Roll torque
International Journal of Mechanical Sciences, 1996Co-Authors: I J FreshwaterAbstract:Abstract The classical theories of Rolling continue to be widely used in practice although finite element methods can provide a more detailed analysis of the deformation during Rolling. Both a homogeneous deformation solution and an inhomogeneous method for calculating the Roll Pressure are reformulated as a development of the classical theories of flat Rolling. The new solutions do not require the gradient of the stress-strain curve d (2 k )/ dφ . This simplifies the computations, leads to consistent estimates of the main Rolling parameters including the calculation of the Roll torque and allows more general yield stress functions to be readily included in solutions for hot or cold Rolling. Data for the Rolling of annealed copper is used to establish the consistency and accuracy of the new solutions.
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Simplified theories of flat Rolling—II. Comparison of calculated and experimental results
International Journal of Mechanical Sciences, 1996Co-Authors: I J FreshwaterAbstract:A simplified inhomogeneous solution for the Roll Pressure has been used as the basis for computing consistent precise estimates of Roll force and Roll torque from the theory of cold flat Rolling. The accuracy of the new method is established in this paper by re-analysing previous data for the Rolling of prestrained copper, data for the Rolling of annealed mild steel and results for the Rolling of low carbon steel with lubrication. Both Swift's stress-strain law and a polynomial function are used to represent the experimental yield data for the Rolled materials.
John G. Lenard - One of the best experts on this subject based on the ideXlab platform.
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Chapter 6 – Applications and Sensitivity Studies
Primer on Flat Rolling, 2020Co-Authors: John G. LenardAbstract:Publisher Summary This chapter analyzes a set of concepts, ideas, and expressions regarding the flat-Rolling process by examining their sensitivity to some of the independent parameters in addition to their applicability in specific situations. This chapter discusses the sensitivity of the predicted magnitudes of the Roll-separating forces and Roll torques, by mathematical models, to various independent parameters such as the coefficient of friction, the reduction, the strain-hardening coefficient, and the entry thickness. This is followed by a comparison of the measured powers required for reducing a strip. This chapter also compares the Roll Pressure distributions as obtained by the friction hill approach and by letting the friction factor vary along the contact. It examines several relations, such as the statically recrystallized grain size and the critical strain, dealing with the metallurgical phenomena during Rolling.
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Applications and Sensitivity Studies
Primer on Flat Rolling, 2020Co-Authors: John G. LenardAbstract:This chapter analyzes a set of concepts, ideas, and expressions regarding the flat-Rolling process by examining their sensitivity to some of the independent parameters in addition to their applicability in specific situations. This chapter discusses the sensitivity of the predicted magnitudes of the Roll-separating forces and Roll torques, by mathematical models, to various independent parameters such as the coefficient of friction, the reduction, the strain-hardening coefficient, and the entry thickness. This is followed by a comparison of the measured powers required for reducing a strip. This chapter also compares the Roll Pressure distributions as obtained by the friction hill approach and by letting the friction factor vary along the contact. It examines several relations, such as the statically recrystallized grain size and the critical strain, dealing with the metallurgical phenomena during Rolling.
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Mathematical and Physical Simulation of the Properties of Hot Rolled Products - Chapter 4 – One-dimensional Modeling of the Flat Rolling Process
Mathematical and Physical Simulation of the Properties of Hot Rolled Products, 1999Co-Authors: John G. Lenard, Maciej Pietrzyk, L CserAbstract:This chapter reviews boundary conditions, connected with tribology, and the initial conditions connected with a material's flow strength. In each, the success or failure of the ability of the model to predict the Rolling variables is dependent on the mathematical rigor of the development, as well as on the knowledge and representation of the boundary and initial conditions: the coefficient of friction and the metal's resistance to deformation. An empirical model and several one-dimensional models are presented, all of which are designed to calculate one or more of the Rolling parameters: the Roll separating force, the Roll torque, the Roll Pressure, the power, the temperature rise, and the forward slip. The sensitivity of the predictions of the models to various parameters is also looked into. Finally, the chapter examines the predictive capabilities of the models, in both cold and hot Rolling processes, by comparing them to experimental results.
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chapter 4 one dimensional modeling of the flat Rolling process
Mathematical and Physical Simulation of the Properties of Hot Rolled Products, 1999Co-Authors: John G. Lenard, Maciej Pietrzyk, L CserAbstract:This chapter reviews boundary conditions, connected with tribology, and the initial conditions connected with a material's flow strength. In each, the success or failure of the ability of the model to predict the Rolling variables is dependent on the mathematical rigor of the development, as well as on the knowledge and representation of the boundary and initial conditions: the coefficient of friction and the metal's resistance to deformation. An empirical model and several one-dimensional models are presented, all of which are designed to calculate one or more of the Rolling parameters: the Roll separating force, the Roll torque, the Roll Pressure, the power, the temperature rise, and the forward slip. The sensitivity of the predictions of the models to various parameters is also looked into. Finally, the chapter examines the predictive capabilities of the models, in both cold and hot Rolling processes, by comparing them to experimental results.
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Measurements of friction during hot Rolling of aluminum strips
Journal of Materials Processing Technology, 1996Co-Authors: H.w. Colquhoun, John G. LenardAbstract:Abstract In order to establish the dependence of the coefficient of friction on Rolling speed and the reduction, commercially pure aluminum strips were Rolled at 500°C, using a 2% oil/water emulsion as the lubricant. The Roll separating forces, Roll torques, the forward slip, the Roll Pressure and the interfacial shear stress were measured as a function of the reduction and the Rolling speed. The coefficient of friction was determined from the shear stress and the Roll Pressure distributions and its magnitude was validated independently. The coefficient of friction was found to increase with reduction and, in general, decrease with Rolling speed. The adhesion theory of friction has been used to explain the observations.
Su Hai Hsiang - One of the best experts on this subject based on the ideXlab platform.
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Study of a 3-D FEM combined with the slab method for shape Rolling
Journal of Materials Processing Technology, 2000Co-Authors: Su Hai HsiangAbstract:Abstract A complex model which combines the rigid–plastic 3-D FEM with the slab method is developed in this paper. In this model, first the plastic deformation zone in the billet was divided into several slabs, each slab being divided into 40 eight-node hexahedral isoparametric elements. Then, the rigid–plastic theory was combined with the equilibrium condition of the slab method. Finally, the metal flow, Roll Pressure, strain and strain ratio, etc. were calculated. Compared with the rigid–plastic 3-D FEM, this complex model confirmed the result to be within an acceptable error. Not only could a great deal of simulation time and storage capacity of CPU be saved, but it was also very suitable in performance for personal computers.
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Analysis of the bulging in shape Rolling by combined 3D-FEM with slab method
International Journal of Materials & Product Technology, 2000Co-Authors: Su Hai HsiangAbstract:In the simulation of bulging in shape Rolling, for the purpose of CPU time saving, a complex method which combined the 3D-FEM with the slab method was developed in this paper. In this model, the deformation zone in the billet was divided into several proper slabs according to the shapes of boundary, and each slab was analysed by 3D-FEM. Then, the equilibrium of the longitudinal force and the condition of volume consistency were applied. Finally, the tendency of metal flow, Roll Pressure, stress and strain rate can be calculated. Compared with the traditional 3D-FEM, the results of this complex model were acceptable. This model had the merit of saving computation time and memory capacity, and it was also very suitable for performing in personal computers.
Laila S. Bayoumi - One of the best experts on this subject based on the ideXlab platform.
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Flow and stresses in round–oval–round Roll pass sequence
International Journal of Mechanical Sciences, 1998Co-Authors: Laila S. BayoumiAbstract:Abstract Analysis of flow and stresses in isothermal steady-state round–oval–round pass sequence for the production of round bars has been obtained from a flowline field solution. The velocity, strain-rate and stress components are derived from kinematic and static considerations together with the material constitutive law and friction boundary conditions. The results obtained show that the Roll Pressure and friction shear traction at the Roll interface are fairly uniform and the normalized average Roll Pressure and friction shear factor have lower values than those for flat bar Rolling at the same Rolling conditions. Small variations in the Rolls clearance gap have no appreciable effect on the Roll load and torque. Increasing friction causes a significant increase in the Roll load and torque. The analysis predicts pass grooves’ dimensions, Roll load and torque for different values of height reductions.
Laila Salah Bayoumi - One of the best experts on this subject based on the ideXlab platform.
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Effect of Roll gap change of oval pass on interfacial slip of workpiece and Roll Pressure in round-oval-round pass Rolling sequence
KSME International Journal, 2002Co-Authors: Laila Salah BayoumiAbstract:This paper presents a study of the effect of varying the Roll gap of oval pass in round-oval-round pass sequence on the interfacial slip of workpiece, entrance and exit velocities, stresses and Roll load that the workpiece experiences during Rolling, by applying analytical method, finite element simulation and verification through hot bar Rolling tests. The results have shown that the Roll gap variation of oval pass affects the interfacial slip of workpiece along the groove contact and the specific Roll Pressure. The optimum conditions in terms of minimum interfacial slip and minimum specific Roll Pressure, which might influence the maximum groove life, is obtained when the subsequent round pass is completely filled.
