EXTERNAL CHILLER FOR CASTING

PURPOSE:To prevent melt sticking of an external chiller for a casting to be used in the stage of casting on the casting at the temp. of the cast molten metal by forming an Al diffused layer on the surface of the chiller. CONSTITUTION:Molten steel is charged from a pouring cup 6 through a sprue 7 into a cavity 4 for casting in a casting mold constituted of top and bottom sand molds 2, 1, in the stage of casting the shoe of an endless tracked vehicle made of cast steel. A round bar-like chiller 9 is disposed in the place required for quick cooling in this case. The chiller 9 is beforehand formed thereon with a diffusion coating layer of Al by dipping in molten Al, a diffusion penetration method of Al, a melt spraying method, etc. The Al diffusion coating layer forms an Fe-Al alloy layer on the steel material of the chiller and since a thin layer of Al2O3 is formed on the surface, the removal of the casting is easy without melt sticking the cast steel and the chiller and the repetitive use of the chiller is possible.