The relationship between heat transfer coefficient and surface temperature of aluminum alloy in water cooling stage is described by inverse method based on measuring temperature distribution of aluminum alloy ingot with diameters in 100 mm in semi-continuous casting with direct water-cooling. The calculated results show that the heat transfer coefficient is increased with decrease in surface temperature of the ingot

and especially decreased temperature from 400 ℃ to 130 ℃

the heat transfer coefficient is dramatically increased

where the maximum value about 23 000 W/（m

2

·K） can be observed at 130 ℃. After that

the heat transfer coefficient is rapidly decreased with temperature decline. A FEM model was built to analyze the temperature field and shell growth of ingot. The calculated results are well in agreement with the experimental ones.