THE TREATMENT OF STEEL
1 Solid-State Transformations in the Iron Carbon System 1 11 Introduction 1 12 Crystalline Structures of the Iron 3 13 Solid Solutions in the Iron 5 131 Substitutional Solid Solutions 5 132 Interstitial Solid Solutions 6 133 Hardness 10 134 Tensile Test 18 135 Toughness 23 14 Alphagenous and Gammagenous Character of the Elements Solubilized in the Iron 27 15 The Metastable Fe–C Equilibrium Diagram 32 151 Steels with 211% C 34 152 Transformations by Equilibrium Cooling of Hypoeutectoid Steels (<077% C) 37 153 Hypoeutectoid Steels with <002% C 43 16 Influence of Alloying Elements in the Fe–C Metastable Diagram 43 17 Non-equilibrium Transformations by Isothermal Cooling of the Austenite 49 171 Metallography and Kinetics of the Pearlitic Transformations 52 172 Bainitic Transformations 59 173 TTT Curves (Transformation-Temperature-Time Curves) 63 18 Transformation of the Austenite into Martensite 64 181 Crystalline Structure and Hardness of the Martensite 65 182 Ms Temperature 71 183 Thermal Difference (?? –T) and Residual Austenite 72 184 Stabilization of the Austenite by Interruption in the Cooling at T < Ms 74 19 Complementary Considerations About the Ferritic-Pearlitic Transformations 75 191 Ferritic-Pearlitic Transformations of the Austenite by Continuous Cooling 76 192 Ferritic-Pearlitic Transformations in Low Alloy Steels 78 110 Designation and Normalization of Steels 79 1101 Different Methods to Designate Steels 79 1102 International Standards for Steels 83 References 84 2 Heat Treatment of Steels 87 21 Introduction 87 22 Austenitization 87 221 Heating to Austenitize 88 222 Cooling from the Austenitic State 97 23 Annealing to Soften the Steel 102 231 Full Annealing 102 232 Intercritical Annealing 103 233 Isothermal Annealing 105 234 Subcritical Annealing 106 24 Normalizing 107 25 Quenching 109 251 Hardenability 110 252 Susceptibility to Cracking Due to Quenching 121 253 Surface Quenching 122 26 Tempering 123 261 General Questions 123 262 Stages of the Martensite Tempering 127 263 T1 Temperature and Time t in the Tempering 136 264 Multiple Tempering Treatments 149 27 Isothermal Treatments 174 271 Patenting 174 272 Austempering 176 273 Martempering 177 274 Sub-Zero Treatments 179 28 Surface Thermochemical Treatments 179 29 Hyperquenching and Aging 185 References 186 3 Thermomechanical Treatments of Steels 189 31 Recrystallization 189 32 Hot Deformation 193 33 Improvements by Hot Forming of the Solidification Structures 195 331 Forge Fibering and Crystalline Texture Anisotropy of Properties 198 34 Thermomechanical Treatments of the Austenite Before Their Allotropic Transformation 204 341 Banded Structure 205 342 Controlled Rolling 210 343 LT Ausforming 223 35 Thermomechanical Treatments of the Austenite During Its Allotropic Transformation 226 351 Isoforming 226 352 TRIP Effect 227 36 Thermomechanical Treatments After the Transformation of the Austenite 230 361 Pearlite Forming 230 362 Martensite Forming 231 References 232 4 Controlled Atmospheres in Furnaces for Heat Treatments 235 41 Introduction 235 42 Formation and Dissociation of Metallic Oxides: Ellingham’s Diagram 236 43 Reduction of Oxides with Gases 246 431 Reduction of an Oxide MxOy in the Presence of a CO–CO2 Gaseous Mixture 246 432 Reduction of an Oxide MxOy with H2 262 433 Reductant or Oxidizing Aptitude of CO–CO2–H2– H2Ovapor Gases Mixture in Equilibrium 264 44 Case-Hardening and Decarburizing of Steels 267 441 Boudouard’s Equilibrium 267 442 Decarburizing-Case Hardening in a CO–CO2 Binary Atmosphere 273 443 Decarburizing-Case Hardening in a Binary Atmosphere of H2–CH4 280 444 Mixture of Gases CO–CO2–H2–CH4–H2O in Equilibrium 281 45 Industrial Atmospheres: C–H–O–N System 292 451 Introduction 292 452 Endothermic and Exothermic Atmospheres 295 453 Atmospheres Obtained from NH3 307 454 The Future of the Industrial Atmospheres 313 46 Complementary Considerations 318 References 319