Vacuum brazing oil cooler bottom plate material and preparation method thereof

The invention discloses a vacuum brazing oil cooler bottom plate material and a preparation method thereof. The preparation method comprises the steps that composite hot rolling is carried out, specifically, a skin material and a core material are compounded and then subjected to hot rolling, and a hot rolled plate is obtained; primary cold rolling is carried out, specifically, the hot rolled plate is subjected to multi-pass cold rolling, the deformation quantity of each pass is 10%-16%, and a cold rolled plate 1 is obtained; primary annealing is carried out, specifically, recrystallization annealing is carried out on the cold rolled sheet 1 to obtain a sheet material; secondary cold rolling is carried out, specifically, the plate is subjected to multi-pass cold rolling, the deformation quantity of each pass is 10%-16%, and a cold rolled plate 2 is obtained; secondary annealing is carried, specifically, recrystallization annealing is carried out on the cold rolled sheet 2; and a skin material is 3003 aluminum