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Castings Practice: The Ten Rules of Castings

by John Campbell

Brief contents

Rule 1 – Achieve a good quality melt

  • Background
  • Melting
  • Holding
  • Pouring
  • Melt treatments
  • Degassing
  • Additions
  • Filtration
  • Packed beds
  • Alternative varieties of filters
  • Practical aspects

Rule 2 – Avoid turbulent entrainment (the critical velocity requirement)

  • Maximum velocity requirement
  • The ‘no fall’ requirement
  • Filling system design
  • Gravity pouring of open-top moulds
  • Gravity pouring of closed moulds
  • Horizontal transfer casting
  • Counter-gravity
  • Surface tension controlled filling
  • Inclusion control: filter sand traps
  • Practical calculation of the filling system

Rule 3 – Avoid laminar entrainment of the surface film
(the non-stopping, non-reversing condition)

  • Continuous expansion of the meniscus
  • Arrest of vertical progress
  • Waterfall flow
  • Horizontal stream flow
  • Hesitation and reversal

Rule 4 – Avoid bubble damage

  • Gravity-filled running systems
  • Pumped and low-pressure filling systems

Rule 5 – Avoid core blows

  • Background
  • Prevention

Rule 6 – Avoid shrinkage damage

  • Feeding systems design background
    • Gravity feeding
    • Computer modelling of feeding
    • Random perturbations to feeding patterns
    • Dangers of solid feeding
    • The non-feeding roles of feeders
  • The seven feeding rules
    • rule 1: Do not feed
    • rule 2: Heat-transfer requirement
    • rule 3: Mass-transfer requirement
    • rule 4: Junction requirement
    • rule 5: Feed path requirement
    • rule 6: Pressure gradient requirement
    • rule 7: Pressure requirement
  • The new feeding logic
    • Background
    • The new approach
  • Active feeding
  • Freezing systems design
    • External chills
    • Internal chills
    • Fins

Rule 7 – Avoid convection damage

  • Convection: the academic background
  • Convection: the engineering imperatives
  • Convection damage and casting section thickness
  • Countering convection

Rule 8. Reduce segregation damage

Rule 9 – Reduce residual stress (the ‘no water quench’ requirement)

  • Residual stress from casting
  • Residual stress from quenching
  • Distortion
  • Heat treatment developments

Rule 10 – Provide location points

  • Date
  • Location points
  • Rectilinear systems
  • Cylindrical systems
  • Trigonal systems
  • Thin-walled boxes
  • Location jigs
    • Clamping points
    • Mould design: the practical issues
    • Casting accuracy
    • Tooling accuracy
  • Mould accuracy
  • Summary of factors affecting accuracy
  • Metrology

Appendix

  • The 1.5 factor
  • The Bernoulli equation
  • Rate of pour of steel castings from a bottom-pour ladle
  • Running system calculation record
  • Design methodology for investment castings

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