Directional Solidification of Steel Castings (eBook)

R. Wlodawer (Autor)

eBook Download: PDF

2013 | 1. Auflage
256 Seiten
Elsevier Science (Verlag)
978-1-4831-4911-0 (ISBN)

Infos

Directional Solidification of Steel Castings summarizes the results of a large number of investigations, mostly scientific in character, on the directional solidification of steel castings. The influence of design on the technical possibilities of producing casting in the foundry is examined. Diagrams, simple basic rules, and formulae are provided, along with many practical examples. This book is comprised of 16 chapters and begins with an introduction to the technical and psychological aspects of steel casting before turning to a discussion of the influence of shape and dimensions on the time it takes for castings to solidify. The thermal gradient, feeder heads, and cavities in steel castings are then considered. In particular, the effect of the thermal gradient on solidification and feeding range are examined. Methods for increasing the thermal gradient in the casting are described, including the use of mold heating pads, breaker cores or Washburn cores; external cooling (iron chills); cooling fins; internal chills; and exothermic pads. Cavities in steel castings which are commonly mistaken for true shrinkage cavities are also analyzed. This monograph is particularly suitable for foundry managers, foremen, technicians, casting designers, and students.

Inhalt

Front Cover 1
Directional Solidification of Steel Castings 4
Copyright Page 5
Table of Contents 6
Foreword To The First Edition 10
Preface To The English Edition 12
From The Introduction To The First Edition 14
CHAPTER 1. INTRODUCTION TO THE ENGLISH EDITION 16
1.1. The Technical Side of This Book 16
1.2. The Psychological Side of This Book 16
CHAPTER 2. THE INFLUENCE OF SHAPE AND DIMENSIONS ON THE TIME TAKEN FOR CASTINGS TO SOLIDIFY 17
2.1. Why Does a Casting Solidify? The Solidification Modulus 17
2.2. The Solidification Time and Modulus of Large Plates 18
2.3. The Influence of Mould Material and Casting Temperature 19
2.4. The Practical Significance of Simplified Modulus Calculations 19
2.5. Further Simplification of the Modulus Calculation by the Use of "Simulation" Bodies–Calculation of Junctions 
22 
2.6. Practical Examples of Modulus Calculations 26
CHAPTER 3. THE THERMAL GRADIENT IN THE CASTING 31
3.1. What Is a Thermal Gradient? 31
3.2. Thermal Gradient and Difference in Modulus 31
3-3- Effect of the Thermal Gradient on Solidification and Feeding Range 32
3.4. Factors Influencing the Feeding Range 36
CHAPTER 4. DETERMINATION OF THE CONNECTOR BETWEEN FEEDER AND CASTING,HERE CALLED FEEDER NECK 
38 
4.1. Calculation of Transition Cross-sections between Feeder and Casting (without Allowing for the Effects of the Flow of Metal) 38
4.2. Calculation of Ingates, Allowing for the Heating Effects of Metal Flow 42
CHAPTER 5. FEEDER HEADS 43
5.1. General 43
5.2. Action of Open Feeder Heads 43
5.3. Mode of Action of Blind Feeder Heads 44
5.4. Behaviour of the Feeder Head during Solidification 47
5.5. Shrinkage 48
5.6. Calculations Giving the Shrinkage Cavity Characteristics of the Best Form of Feeder Head and the Compensating Factor 50
5.7. Influence of the Structure of the Shrinkage Cavity on the Maximum Yield 69
5.8. Feeder Head Calculations 71
5.9. Examples of Feeder Head Calculation 75
5.10. Other Methods of Calculating Feeder Heads 82
CHAPTER 6. INCREASING THE THERMAL GRADIENT IN THE CASTING BY PADDING AND BY THE UTILIZATION OF NATURAL END ZONES 
83 
6.1. Utilization of Natural End Zones and Shape of the Feeder General 
83 
6.2. Use of the Heuvers (14) Circle Method for Castings 84
6.3. Calculation of the Modulus Curve 95
6.4. Further Development and Simplification in Practice of the Methods of Heuvers (14) and Stein18 
97 
6.5. Casting Sound Tubes 99
CHAPTER 7. INCREASING THE THERMAL GRADIENT BY MEANS OF MOULD HEATING PADS BREAKER CORES OR WASHBURN CORES 
101 
7.1. General Thermal Conditions Relating to Breaker Cores and Mould Heating Pads 101
7.2. Calculation of Washburn Cores and Mould Heating Pads on the Basis of the Thermal Conditions 103
7.3. On the Practice of Washburn Cores, Heating Pads and Internal Feeders 106
7.4. The Heating of Thin Sections of Moulding Sand. Influence on the Size of the Feeder Head. The Minimum Lengths of Ingates Which Will Prevent Harmful Sand Fillet Effects 110
CHAPTER 8. INCREASING THE THERMAL GRADIENT BY EXTERNAL COOLING 
121 
8.1. The Formation of Artificial End Zones by the Use of Chills 121
8.2. Measures Against Cracking Taken by the Use of Chills. Cooling of Junctions 129
8.3. Porosity at the Point of Attachment of Chills 132
8.4. Tears at the Points of Attachment of Chills 136
8.5. Principles of Calculating External Chills 138
8.6. Operating Practice in Cooling Heavy Cross-sections by Means of Chills 144
8.7. Shrinkage Cavity Due to the Incorrect Placing of Chills 147
8.8. Use of Contoured Chills 148
CHAPTER 9. INCREASING THE THERMAL GRADIENT BY MEANS OF COOLING FINS 151
9.1. General Discussion of the Action of Cooling Fins 151
9-2. Effect on the Modulus of the Prior Solidification of Adjacent Cross-sections on Wedge Plates with Attached Fins. Determination of the Modulus on Wedge Plates 152
CHAPTER 10. INCREASING THE THERMAL GRADIENT BY MEANS OF MOULDING MATERIALS WITH A CHILLING ACTION 154
10.1. Different Heat Removal Rates of Various Moulding Materials. Defects Arising from Their Use 154
10.2. Calculation of Moulding Materials with a Chilling Action 156
10.3. Practical Application and Calculation of Moulding Materials Having a Chilling Action 157
10.4. Manufacture of Extended Artificial End Zones by Means of Chilling Materials 159
10.5· Displacement of the Segregated Zone by the Use of Moulding Materials with a Chilling Action 159
CHAPTER 11. INCREASING THE THERMAL GRADIENT BY THE USE OF INTERNAL CHILLS 161
11.1. General 161
11.2. The Heat Balance of Welded-in Chills 164
11.3. The Transfer of Heat When WTelding the Chill to the Casting 166
11.4. The Influence of Temperature on the Melt-down Time of Chill Sections 167
11.5. The Dimensions of Welded-in Chill Sections as a Function of Steel Temperature and the Desired Chilling Effect 168
11.6. The Use of Non-bonding Internal Chills 169
11.7. Checking the Methods of Calculating Internal Chills 170
11.8. The Chilling Characteristics of Chaplets 172
11.9. Examples of the Use of Internal Chills 174
CHAPTER 12. THE CALCULATION OF EXOTHERMIC FEEDER HEAD MATERIALS 178
12.1. General 178
12.2. Principles of Calculation of Exothermic Feeder Heads, with Reference to Exothermic Sleeves 178
12.3. The Characteristic of Exothermic Feeder Heads 186
12.4. On the Practice of Exothermic Feeder Head Manufacture 199
12.5. Practical Examples and Hints for the Use of Exothermic Feeder Heads 202
12.6. The Economics of Exothermic Feeder Heads 212
12.7. The Use of Exothermic Antipiping Powder 218
12.8. Heat Theory and the Calculation of Exothermic Materials 227
CHAPTER 13. THE USE OF EXOTHERMIC PADS TO INCREASE THE THERMAL GRADIENT 229
13.1. Principles of the Calculation of Exothermic Pads 229
13.2. Shape and Venting of Exothermic Pads. Heated Breaker Cores 233
13.3. Examples of the Use of Exothermic Pads 235
13.4. Frequently Occurring Defects with Exothermic Pads 243
CHAPTER 14. BRIEF NOTE ON THE USE OF INSULATING MATERIALS IN STEEL CASTINGS 247
CHAPTER 15. CAVITIES IN STEEL CASTINGS WHICH ARE FREQUENTLY CONFUSED WITH TRUE SHRINKAGE CAVITIES 248
15.1. Blowholes Which Can Be Confused with Shrinkage Cavities 248
15.2. Slag Blowholes, Which Are Confused with Shrinkage Cavities 250
CHAPTER 16. FINAL BRIEF WORD 255
CONVERSION FACTORS 256
SYMBOLS USED IN THIS BOOK 256
REFERENCES 257

Produkt-Details

• Erscheint lt. Verlag: 22.10.2013
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Physik / Astronomie
• Themenwelt: Technik
• Themenwelt: Wirtschaft
• ISBN-10: 1-4831-4911-0 / 1483149110
• ISBN-13: 978-1-4831-4911-0 / 9781483149110