Convection Currents in Gray Cast Iron

Abstract

Experimental evidence is presented showing that convection currents exist in molten iron while the iron is solidifying in the mold. Bleeding experiments have revealed a consistent tendency for walls if gray iron castings to solidify more rapidly at the bottom than at the top. Cooling curves were obtained by inserting thermocouples into various positions in bottom poured test castings. From these curves it is possible to trace the flow of hot metal from the bottom to the top of the castings. From temperature measurements on a variety of test castings it was possible to conclude that convection currents are of sufficient magnitude and act long enough in gray cast iron to cause bottom poured castings to freeze from the bottom toward the top. This mode of freezing is dependent on pouring temperatures and size of castings.

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Document Details

Document Type
Technical Report
Publication Date
Dec 06, 1946
Accession Number
AD1203338

Entities

People

  • J. H. Schaum

Organizations

  • United States Naval Research Laboratory

Tags

DTIC Thesaurus Topics

  • Convection
  • Cooling
  • Critical Temperature
  • Freezing
  • Glass Transition Temperature
  • Isothermal Processes
  • Measurement
  • Thermocouples
  • Transition Temperature

Fields of Study

  • Materials science

Readers

  • Coastal Oceanography
  • Metallurgy
  • Thermal Physics or Thermal Science.