Method of making a composite metal casting

A method of making a metal casting composed of a steel plate and aluminum material interlocked with said steel plate, which comprises the steps of:

• a. providing the steel plate having opposed surfaces;
• b. raising up the skin of said steel plate from at least one of said opposed surfaces for forming a plurality of teeth with primary interstices therebetween and causing said teeth to have at least one face with a number of flaws therein formed during the formation of said teeth and providing substantially irregular interstices;
• c. forming said steel plate with said teeth into a desired shape;
• d. pouring aluminum material in a molten state onto said surface of said steel plate having said plurality of teeth therein so that the molten aluminum material penetrates into said primary and irregular interstices;
• and
• e. cooling the thus obtained product to provide a firm interlocking between said steel plate and said aluminum material upon solidification thereof.