| An aluminum alloy die casting and die was designed such that temperatures could be measured in the die near the casting. These temperatures were compared to the results of numerical simulation of the heat flow during solidification and cooling of the castings. Computation of the interfacial heat transfer coefficients was based on the simulations that gave the best fit to experiments. Time independent heat transfer coefficients were shown to give as good a fit to the data as time dependent values.; The solidification time of the 7 mm thick casting was linearly dependent on the die temperature, and varied between about 2.5 and 5 seconds.; For aluminum alloy 380 castings, with liquid metal held in the furnace at 650{dollar}spcirc{dollar}C, the heat transfer coefficients are about 80 kW m{dollar}sp{lcub}-2{rcub}spcirc{dollar}C{dollar}sp{lcub}-1{rcub}{dollar} for die surfaces roughened by 120 grit paper. For dies that were not roughened, the heat transfer coefficients are about 35 kW m{dollar}sp{lcub}-2{rcub}spcirc{dollar}C{dollar}sp{lcub}-1{rcub}.{dollar} For each case, the alloy lost an amount of heat equivalent to about 120{dollar}spcirc{dollar}C of superheat between furnace and casting cavity. Thus, the alloy entered the casting cavity with a few percent solidified. Heavy lubrication application of four seconds spray increased the heat transfer coefficient at one die surface by a few percent as compared to light lubrication application.; With 380 alloy at furnace temperature of 760{dollar}spcirc{dollar}C, the heat transfer coefficients on one surface increased to greater than 120 kW m{dollar}sp{lcub}-2{rcub}spcirc{dollar}C{dollar}sp{lcub}-1{rcub}.{dollar} The temperature loss from furnace to casting was about 160{dollar}spcirc{dollar}C. These castings took about 1 second longer to freeze than the 650{dollar}spcirc{dollar}C alloy temperature case.; Alloy 390 castings took longer to freeze than 380 alloy castings, because of the higher enthalpy of fusion.; Intensification metal pressure of 120 MPa caused only a small increase in heat transfer coefficient, and then only for the lightly lubricated condition. |
