by Cho, King-sum. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 108-110). / Text in English; abstracts in English and Chinese. / by Cho, King-sum. / Abstract --- p.i / 摘要 --- p.iii / Acknowledgment --- p.iv / Contents --- p.v / List of figures --- p.x / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Review of non-destructive techniques --- p.2 / Chapter 1.1.1 --- Liquid penetration technique --- p.2 / Chapter 1.1.2 --- Eddy current inspection --- p.2 / Chapter 1.1.3 --- Ultrasonic testing --- p.3 / Chapter 1.1.4 --- Radiography --- p.3 / Chapter 1.1.5 --- Magnetic testing methods --- p.4 / Chapter 1.2 --- Barkhausen emission --- p.4 / Chapter 1.3 --- The development of Barkhausen Emission --- p.5 / Chapter 1.4 --- The advantages of using Barkhausen emission --- p.6 / Figures for chapter1 --- p.8 / Chapter 2 --- Iron-carbon System --- p.9 / Chapter 2.1 --- Iron-iron carbide phase diagram --- p.9 / Chapter 2.2 --- Invariant reactions in the Fe-Fe3C phase diagram --- p.11 / Chapter 2.3 --- Classification of carbon steels --- p.12 / Chapter 2.4 --- Effect of heat treatment on plain-carbon steels --- p.13 / Chapter 2.4.1 --- Annealing and normalizing --- p.14 / Chapter 2.4.2 --- Slow cooling --- p.15 / Chapter 2.5 --- Process of recovery and recrystallization --- p.15 / Chapter 2.5.1 --- Recovery --- p.16 / Chapter 2.5.2 --- Recrystallization --- p.16 / Chapter 2.5.3 --- Grain growth --- p.17 / Figures for chapter2 --- p.18 / Chapter 3 --- Background Theory --- p.23 / Chapter 3.1 --- Ferromagnetism --- p.23 / Chapter 3.1.1 --- Localized moment theory --- p.24 / Chapter 3.1.2 --- Band theory --- p.25 / Chapter 3.1.3 --- Hysteresis loop --- p.25 / Chapter 3.2 --- Domain theory --- p.26 / Chapter 3.2.1 --- Magnetic domain --- p.26 / Chapter 3.2.2 --- Structure of domain wall --- p.27 / Chapter 3.2.3 --- Domain wall motion --- p.29 / Chapter 3.2.4 --- Magnetostatic energy --- p.30 / Chapter 3.2.5 --- Magnetization process --- p.32 / Chapter 3.3 --- Effect of applied stress --- p.33 / Chapter 3.3.1 --- Stress --- p.33 / Chapter 3.3.2 --- Magnetostriction --- p.34 / Chapter 3.3.3 --- Effect of stress on magnetization --- p.34 / Figures for chapter 3 --- p.37 / Chapter 4 --- Instrumentation --- p.39 / Chapter 4.1 --- Introduction --- p.39 / Chapter 4.2 --- Experimental setup for Barkhausen emission --- p.39 / Chapter 4.2.1 --- Magnetizing unit --- p.40 / Chapter 4.2.2 --- Signal detection unit --- p.41 / Chapter 4.2.3 --- Signal processing unit --- p.42 / Chapter 4.3 --- The typical BE profile --- p.42 / Chapter 4.4 --- Specimen treatment --- p.43 / Chapter 4.4.1 --- Optical microscope --- p.43 / Chapter 4.4.2 --- Vickers´ة hardness tester --- p.44 / Chapter 4.4.3 --- Thermal resistance furnace --- p.45 / Chapter 4.4.4 --- Instron loading machine --- p.45 / Figures for chapter4 --- p.47 / Chapter 5 --- Experiments and Results: Evaluation of Carbon Content in Steel --- p.52 / Chapter 5.1 --- Introduction --- p.52 / Chapter 5.2 --- Experiments and results --- p.52 / Chapter 5.3 --- Discussions --- p.53 / Chapter 5.3.1 --- The magnetization process --- p.53 / Chapter 5.3.2 --- The BE profiles 、 --- p.54 / Chapter 5.3.3 --- Hardness --- p.57 / Chapter 5.4 --- Conclusions --- p.57 / Figures for chapter5 --- p.58 / Chapter 6 --- Experiments and Results: The Effects of annealing on Barkhausen Emission in Mild Steel Bars --- p.64 / Chapter 6.1 --- Introduction --- p.64 / Chapter 6.2 --- Experiments --- p.64 / Chapter 6.3 --- Results and discussions --- p.64 / Chapter 6.3.1 --- The mechanical properties --- p.65 / Chapter 6.3.2 --- Grain size --- p.65 / Chapter 6.3.3 --- BE profiles --- p.66 / Chapter 6.4 --- Conclusions --- p.67 / Figures for chapter6 --- p.68 / Chapter 7 --- Experiments and Results: The Effects of Dynamic and Residual Stresses on Barkhausen Emission in Annealed Mild Steel Bars --- p.76 / Chapter 7.1 --- Introduction --- p.76 / Chapter 7.2 --- Experiments --- p.76 / Chapter 7.2.1 --- Measurement of dynamic loading (with samples of Set A) --- p.77 / Chapter 7.2.2 --- Measurement of residual stress (with samples of Set B) --- p.77 / Chapter 7.2.3 --- Measurement of continuous tensile stress (with samples of Set C) --- p.77 / Chapter 7.3 --- Results and discussions --- p.78 / Chapter 7.3.1 --- Peak ratio of the BE profile --- p.78 / Chapter 7.3.2 --- The initial peak value under the effects of increasing tensile stress --- p.81 / Chapter 7.4 --- Conclusions --- p.82 / Figures for chapter7 --- p.83 / Chapter 8 --- Experiments and Results: The Recovery of Strained Steel Bars by Annealing --- p.94 / Chapter 8.1 --- Introduction --- p.94 / Chapter 8.2 --- Experiments --- p.94 / Chapter 8.2.1 --- Measurement of annealed sample (Set D) --- p.95 / Chapter 8.2.2 --- Results of the Set E samples --- p.95 / Chapter 8.3 --- Results and discussions --- p.95 / Chapter 8.3.1 --- Hardness --- p.96 / Chapter 8.3.2 --- Peak ratio of the BE profile --- p.97 / Chapter 8.3.3 --- BE profile for the samples of Set E --- p.98 / Chapter 8.4 --- Conclusions --- p.99 / Figures for chapter8 --- p.100 / Chapter 9 --- Conclusions and Suggestions for Further Studies --- p.104 / Bibliography --- p.108