The invention discloses a composite
metal shell and a manufacturing method thereof. The manufacturing method of the composite
metal shell comprises the following steps: providing a first
metal base material; the first metal base material is subjected to hot
forging machining to form a metal inner shell, the metal inner shell comprises a main body and a boss, and the boss protrudes from the main body; performing chemical micropore
etching on the metal inner shell; a shell metal layer comprising second metal is formed on the side, provided with the boss, of the main body through
die casting, and the boss is embedded in the shell metal layer; a groove is formed in the side, away from the boss, of the main body, and the groove penetrates through the main body and extends into the boss. In the composite metal shell provided by the invention, the groove can avoid the junction of the metal inner shell and the metal layer of the outer shell, so that a chemical film with uniform thickness can be formed on the inner wall of the groove in a
chemical process, the composite metal shell can be effectively protected, and the probability of
corrosion at the groove is reduced.