Directional Solidification of Steel Castings

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.

Foreword to the First EditionPreface to the English EditionFrom the Introduction to the First EditionChapter 1. Introduction to the English Edition 1.1. The Technical Side of This Book 1.2. The Psychological Side of This BookChapter 2. The Influence of Shape and Dimensions on the Time Taken for Castings to Solidify 2.1. Why Does a Casting Solidify? The Solidification Modulus 2.2. The Solidification Time and Modulus of Large Plates 2.3. The Influence of Mould Material and Casting Temperature 2.4. The Practical Significance of Simplified Modulus Calculations 2.5. Further Simplification of the Modulus Calculation by the Use of "Simulation" Bodies-Calculation of Junctions 2.6. Practical Examples of Modulus CalculationsChapter 3. The Thermal Gradient in the Casting 3.1. What is a Thermal Gradient? 3.2. Thermal Gradient and Difference in Modulus 3.3. Effect of the Thermal Gradient on Solidification and Feeding Range 3.3.1. Solidification Characteristics of Rectangular Section Bars 3.4. Factors Influencing the Feeding RangeChapter 4. Determination of the Connector between Feeder and Casting (Feeder Neck) 4.1. Calculation of Transition Cross-sections between Feeder and Casting (without Allowing for the Effects of the Flow of Metal) 4.2. Calculation of Ingates, Allowing for the Heating Effects of Metal FlowChapter 5. Feeder Heads 5.1. General 5.2. Action of Open Feeder Heads 5.3. Mode of Action of Blind Feeder Heads 5.4. Behavior of the Feeder Head during Solidification 5.5. Shrinkage 5.6. Calculations Giving the Shrinkage Cavity Characteristics of the Best Form of Feeder Head and the Compensating Factor 5.7. Influence of the Structure of the Shrinkage Cavity on the Maximum Yield 5.8. Feeder Head Calculations 5.9. Examples of Feeder Head Calculation 5.10. Other Methods of Calculating Feeder HeadsChapter 6. Increasing the Thermal Gradient in the Casting by Padding and by the Utilization of Natural End Zones 6.1. Utilization of Natural End Zones and Shape of the Feeder. General 6.2. Use of the Heuvers(14) Circle Method for Castings 6.2.1. Use of the Circle Method for Extending Feeder Zones. Feeding of Bars and Bosses 6.2.2. Application of the Circle Method to Junctions in a Complex Casting 6.3. Calculation of the Modulus Curve 6.4. Further Development and Simplification in Practice of the Methods of Heuvers(14) and Stein(16) 6.5. Casting Sound TubesChapter 7. Increasing the Thermal Gradient by Means of Mould Heating Pads. Breaker Cores or Washburn Cores 7.1. General Thermal Conditions Relating to Breaker Cores and Mould Heating Pads 7.2. Calculation of Washburn Cores and Mould Heating Pads on the Basis of the Thermal Conditions 7.2.1. Calculation of Internal Feeders 7.3. On the Practice of Washburn Cores, Heating Pads and Internal Feeders 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 7.4.1. Harmful Effects of Hot Spots 7.4.2. The Heating of Plane Core Plates by the Superheat of the Liquid Steel 7.4.3. The Decrease in the Cooling Surface Areas of Core Plates as a Result of Heating 7.4.4. Calculation of the Cooling Action of Cores in Long Tubular Bodies 7.4.5. Calculation of the Cooling Action of Cores in Short Tubular Bodies (Discs and Rings) 7.4.6. Retardation of the Solidification Period by Heating 7.4.7. Checking the Calculations for Tubular Castings by Measuring the Solidification Time 7.4.8. Retention of Heat in Junctions 7.4.9. The Importance of the Heating Effect in Feeder Calculations 7.4.10. Approximate Hub Calculations 7.4.11. Special Features of the Heating Effect in the Placing of Blind Feeder HeadsChapter 8.