Modeling Steel Deformation in the Semi-Solid State (eBook)

Dr Marcin Hojny is a researcher and lecturer at the AGH University of Science and Technology in Cracow, Poland, where he lectures on concurrent design systems as well as numerical methods and simulations. He is the author of the continuously developed DEFFEM simulation package as a development aid intended for use with modern Gleeble series research workstations. His scientific interests include the practical use of physical and computer simulations within the context of new technology development aids, mainly for the aviation and automotive industries. In particular, his work explores the modelling of processes and phenomena occurring at temperatures exceeding those seen in classic hot forming processing. He is the author of over 100 articles, including 16 from the Journal Citation Report (JCR) list, as well as two published books.

Acknowledgments 6
Contents 7
Nomenclature 10
Abstract 13
1 Introduction 14
2 State of the Art 18
References 33
3 Aim of the Study 41
4 Integration of Physical and Computer Simulation 43
4.1 Characteristics of the Integrated Modelling Concept 43
4.2 Hybrid Analytical-Numerical Model of Mushy Steel Deformation 48
4.2.1 Resistance Heating Model 52
4.3 “One Decision Software”—The DEFFEM Package 54
4.4 Stereoscopic Visual Representation Algorithm for the 3D Gemini Barco Projection System 57
4.5 Summary 65
References 65
5 Spatial Solutions Based on the Smoothed Particle Method and the Finite Element Method—A Hybrid Approach 67
5.1 The Smoothed Particle Hydrodynamics (SPH) Method 67
5.1.1 Fluid Model 69
5.1.2 Thermal Model 71
5.2 Test Cases to Validate the Fluid Solver 72
5.2.1 Free Particles Fall 72
5.2.2 Structure Impact 76
5.3 Test Simulation of the Hybrid Solution 78
5.4 Summary 84
References 85
6 Spatial Solutions Based on the Finite Element Method and the Monte Carlo Method—A Multi-scale Approach 86
6.1 Thermal Model 86
6.1.1 Discretization for Steady Heat Flow Cases 91
6.1.2 Discretization for Transient Heat Flow Cases 92
6.2 Solidification Model 93
6.3 Mechanical Model 95
6.3.1 Spatial Solution 97
6.3.1.1 Transformation of the Coordinate System and Integration 103
6.3.1.2 Time Problem 108
6.4 Grain Growth Model in the Comprehensive Description of the Heating-Melting-Solidification Process (Multi-scale Approach) 110
References 112
7 Computer-Aided Physical Simulations Within the Context of New Technology Development 113
7.1 Material and Test Methodology 115
7.1.1 Samples and Tools 116
7.1.2 The Determination of Characteristic Temperatures 117
7.1.3 Thermal Process Map (TPM) 120
7.2 Preliminary Experimental and Computer Simulation Research of Steel Deformation in the Semi-solid State 121
7.2.1 The Dependence of Steel Microstructure Parameters on the Cooling Rate During Solidification 126
7.2.2 High-Temperature Stress-Strain Relationships 129
7.2.3 Steel Ductility in the Continuous Casting Process 135
7.2.4 Deformation Above Nil Ductility Temperature 138
7.2.5 Macrostructure and Microstructure 141
7.3 Summary 153
References 155
8 An Integrated Modelling Concept Based upon Axially Symmetrical Models 156
8.1 Direct Simulation Using the Gleeble Thermo-Mechanical Simulator 156
8.1.1 Testing the Temperature Distribution 157
8.1.2 Macrostructure and Microstructure 160
8.2 Application of Tomography to the Spatial Analysis of the Melting Zone 168
8.3 Numerical Modelling with the DEFFEM Simulation System 175
8.3.1 Modelling of the Resistance Heating Process 175
8.3.1.1 Example Results of Resistance Heating 180
8.3.2 Modelling of the Deformation Process 186
8.3.2.1 Rheological Model 188
8.3.2.2 The Numerical Identification Methodology (NIM) for the Low Temperature Range 189
8.3.2.3 The Direct Identification Methodology (DIM) for the Extra-High Temperature Range 192
8.3.2.4 The Numerical Identification Methodology (NIM) for the Extra-High Temperature Range 198
8.4 Summary 207
References 208
9 An Integrated Modelling Concept Based upon Three-Dimensional Models 209
9.1 Modified Experimental Research Methodology 209
9.2 Resistance Heating Model 212
9.3 Modelling of the Resistance Heating Process 214
9.4 Modelling of the Deformation Process 224
9.5 Conceptual Microstructure Estimation Methodology 228
9.6 Modelling Grain Growth in a Complex Approach of the Heating-Melting-Cooling Process 239
9.6.1 Research Methodology and Plan 243
9.6.2 Macrostructural Tests 244
9.6.3 Numerical Modelling of Grain Growth 250
9.7 Summary 263
References 265
10 Summary and Future Work 266
Appendix A: Thermo-physical Properties of the S355 Grade Steel 269
Appendix B: Thermo-physical Properties of the C45 Grade Steel 273
Appendix C: Complete Source Code: Steady Heat Flow 278
Appendix D: Subroutine: Gauss Method 291
Appendix E: Subroutine: Transformation and Integration (3D) 294
Appendix F: Function Calculating Geometry for Stereo Presentation 303