Process Modelling of Metal Forming and Thermomechanical Treatment

ISBN-13: 9783642827907 / Angielski / Miękka / 2011 / 412 str.

Claudio R. Boer; Nuno M. R. S. Rebelo; Hans A. B. Rydstad

Opis

It is the objective of the series IIMaterials Research and Engineeringll to publish information on technical facts and pro cesses together with specific scientific models and theories. Fundamental considerations assist in the recognition of the origin of properties and the roots of processes. By providing a higher level of understanding, such considerations form the basis for further improving the quality of both traditional and future engineering materials, as well as the efficiency of industrial operations. In a more general sense, theory helps to integrate facts into a framework which ties relations between physical equilibria and mechanisms on the one hand, product development and econo mical competition on the other. Aspects of environmental compati bili ty, conservation of resources and of socio-cul tural inter action form the final horizon - a subject treated in the first ll volume of this series, IIMaterials in World Perspective . The four authors of the present book endeavor to present a comprehensive picture of process modelling in the important field of metal forming and thermomechanical treatment. The reader will be introduced to the rapidly-growing new field of application of computer-aided numerical methods to the quanti tative simulation of complex technical processes. Extensive use is made of the state of scientific knowledge related to materials behavior under mechanical stress and thermal treat ment."

Spis treści

1 Preface.- 2 Mathematical Modelling.- 2.1 Introduction.- 2.2 Infinitesimal Theory of Plasticity.- 2.2.1 Yield Criteria.- 2.2.2 Work Hardening.- 2.2.3 Plastic Deformation.- 2.3 Problem Solution.- 2.3.1 System Approach.- 2.3.2 Detailed Mechanics Approach.- 2.4 Elementary Analysis or “Slab Method”.- 2.4.1 The General Case.- 2.4.2 The Plane Strain Situation.- 2.4.2.1 Frictionless Strip Drawing.- 2.4.2.2 Lateral Flow between Parallel Dies.- 2.4.2.3 Plane Strain Lateral Flow between Inclined Dies.- 2.4.2.4 Flow into a Rib.- 2.4.3 The Axisymmetric Situation.- 2.4.3.1 Stress Distribution for the Flat Axisymmetric Case.- 2.4.3.2 Stress Distribution for Converging Outward Flow.- 2.5 Upper-Bound Method.- 2.6 Finite Element Analysis.- 2.6.1 Introduction and Historical Perspective.- 2.6.2 Finite Element Background.- 2.6.3 Stress-Strain Formulations.- 2.6.3.1 Elastic-Plastic Formulations.- 2.6.3.2 Rigid-Plastic Formulations.- 2.6.4 Thermal Formulations.- 2.6.5 Finite Element Equations.- 2.6.5.1 Velocity Equations.- 2.6.5.2 Temperature Equations.- 2.6.5.3 Time Dimension.- 2.6.6 Forming Specifics.- 2.6.7 Summary and Future Developments.- References Chapter 2.- 3 Physical Modelling.- 3.1 Similarity Theory.- 3.1.1 Basic Principles.- 3.1.2 Similarity Laws in Metal Forming.- 3.2 Application and Basic Techniques.- 3.3 Material Flow in Forging — Examples.- 3.4 Simulation of Material Deformation in Turbine Blade Forging.- 3.5 Conclusions.- References Chapter 3.- 4 Modelling of Forging.- 4.1 Introduction.- 4.2 System Modelling in Hot Die Upsetting.- 4.2.1 Heat Transfer Analysis.- 4.2.2 Non-Dimensional Analysis.- 4.2.3 Hot-Die Upsetting System Modelling.- 4.2.3.1 Temperature Calculation.- 4.2.3.2 Stress and Strain Calculation.- 4.2.3.3 Determination of the Shearing Zone in Closed Die Forging.- 4.2.3.4 Stresses.- 4.2.3.5 Flash Width Calculation.- 4.2.3.6 Force Calculations.- 4.2.3.7 Description of the Computer Program.- 4.2.3.8 Experimental Verification of the System Modelling.- 4.2.4 Optimization of Process Parameters.- 4.2.4.1 Geometrical Parameters.- 4.2.4.2 Maximum Allowable Die Stress.- 4.2.4.3 Influence of Thermal Barrier Thickness.- 4.2.4.4 Optimum Conditions for Forging NIM 80 A Billets.- 4.2.4.5 Isolines of Maximum Deformation.- 4.2.4.6 Evaluation of Optimum Variable Ram Speed.- 4.2.5 Coupled FEM Analysis of Forging.- 4.2.5.1 Introduction.- 4.2.5.2 Principle of Induction Heating.- 4.2.5.3 Influence of an Inhomogeneous Temperature Distribution on the Forging Process.- 4.2.5.4 Process Model and Boundary Conditions.- 4.2.5.5 Calculations, Experiments and Results.- 4.2.5.6 Local Strain and Temperature Distribution.- 4.2.5.7 Future Applications of Coupled FEM Process Models.- 4.3 Plane Strain Modelling of Closed Die Forging.- 4.3.1 Elementary Analysis Approach.- 4.3.2 CAD/CAM and Process Modelling of Closed Die Forging.- 4.3.2.1 The DIEDESIGN Software.- 4.3.2.2 Geometrical Input Data Description.- 4.3.2.3 Process Modelling of the Forging Process.- 4.3.2.4 Forging Loads Minimization and Flash Positioning.- 4.3.2.5 Preform and Flash Definition.- 4.3.2.6 Center of Loading.- 4.3.3 Application of CAD/CAM to Forge a Blade in a Nickel-Base Alloy.- 4.3.4 FEM Plane Strain Analysis of Blade Forging.- 4.3.4.1 Deformations.- 4.3.4.2 Effective Strains and Strain Rates.- 4.3.4.3 Stresses.- 4.3.4.4 Friction.- 4.4 Plan Strain Modelling of Thin Rib Forging.- 4.4.1 Elementary Analysis Approach.- 4.4.1.1 Forging Stress Distribution.- 4.4.1.2 Plate-Rib Forging Model.- 4.4.1.3 Rib Forging Model.- 4.4.1.4 Rib Forging Model with the Effect of the Radius.- 4.4.1.5 Experiments and Results.- 4.4.1.6 Conclusions.- 4.4.2 FEM Plane Strain Analysis of Thin Rib Forging.- 4.4.2.1 The FEM Model for the Rib Forging.- 4.4.2.2 Metal Deformation.- 4.4.2.3 Strain Distribution.- 4.4.2.4 Forging Pressure.- 4.4.3 Stress and Strain Analysis of Forging Dies.- 4.4.3.1 The Finite Element Model.- 4.4.3.2 Deformations at the Nodal Points.- 4.4.3.3 Stress Distribution.- 4.5 Finite Element Analysis of a Complex Axisymmetric Shape.- 4.5.1 Deformations.- 4.5.2 Strains.- 4.5.3 Die Stress.- References Chapter 4.- 5 Modelling of Rolling.- 5.1 Introduction.- 5.2 Measurements of Lateral Spread.- 5.3 Computer-Aided Roll Pass Design.- 5.3.1 Input of the Geometry of the Profile.- 5.3.2 Modifications to the Profile.- 5.3.3 Calculation and Modification of the Neutral Line.- 5.3.4 Determination of the Starting Profile (Preform).- 5.3.5 Roll Forming Parameters Calculations.- 5.3.6 Roll Pass Schedule and Roll Geometry.- 5.4 Results.- 5.5 CAD/CAM in Steel Profile Production.- 5.5.1 CAD of Shape Rolls.- 5.5.2 CAM of Shape Rolls at the CAD Workstation.- References Chapter 5.- 6 Modelling of Drawing.- 6.1 Introduction.- 6.2 Upper-Bound Analysis of Round-To-Square Drawing.- 6.2.1 The Upper-Bound Solution.- 6.2.2 The Geometrical Model.- 6.2.3 The Velocity Fields.- 6.2.4 Reduction of Area.- 6.2.5 Flow Lines.- 6.2.6 Optimization of the Theoretical Flow Field.- 6.2.7 Analysis of Process Parameters.- 6.2.8 Conclusions.- 6.3 Finite Element Analysis of Bar Drawing.- 6.3.1 The Finite Element Approach.- 6.3.2 Finite Element Formulation.- 6.3.3 Optimization.- 6.3.4 Finite Element Model.- 6.3.5 Restraints, Die Boundaries and Initial Conditions.- 6.3.6 Finite Element Results.- 6.3.7 Conclusions.- References Chapter 6.- 7 Modelling of Thermomechanical Treatment.- 7.1 Introduction.- 7.2 Determination of Heat Transfer Coefficients in Quenching.- 7.2.1 Approach to the Determination of the Heat Transfer Coefficient.- 7.2.2 Experimental Setup.- 7.2.3 Results.- 7.3 Quenching of Steel Plate through Water Flushing.- 7.3.1 Introduction.- 7.3.2 Analysis of the Heat Transfer.- 7.3.3 Influence of Scale Formation on the Heat Transfer.- 7.3.4 Experimental Technique.- 7.3.5 Material Properties.- 7.3.6 Experimental Results.- 7.4 Modelling of Quenching of Complex Parts.- 7.4.1 Introduction.- 7.4.2 Quenching of an Aluminum Impeller.- 7.4.3 Simulation.- 7.4.3.1 Temperature Calculations.- 7.4.3.2 Residual Stress and Distortion Calculations.- 7.4.4 Comparison with Experiments.- 7.4.5 Conclusions.- 7.5 Modelling of Heat Treatment of Large Forgings.- References Chapter 7.- 8 Outlook.