THE ALUMINUM ALLOY SUB-FRAME FOR A CAR, AND THE MANRFACTURING METHOD OF THE SAME

摘要

An aluminum sub-frame for automobile which reduces weight of an automobile and improves durability of the automobile by having a light weight and excellent mechanical properties compared to a conventional steel sub-frame, and a manufacturing method of the aluminum sub-frame for automobile, which substantially improves productivity by optimizing extrusion conditions in the manufacturing process, are provided. A manufacturing method of an aluminum sub-frame(1) for automobile comprises the steps of: homogenizing the billet after melting an aluminum alloy and casting the molten aluminum alloy into a billet; extruding the billet into hollow shaped materials for rectangular pipe-shaped front and rear members(11,12), subjecting the hollow shaped materials to solution treatment, and cutting the solution treatment-completed hollow shaped materials to predetermined lengths; sequentially performing bending, upsetting, side bending and hole-machining on a hollow shaped material for the front member to manufacture the front member; sequentially performing bending, upsetting, first side bending and second side bending on a hollow shaped material for the rear member to manufacture the rear member; pressing an aluminum alloy plate to manufacture a pair of side members(13); age hardening the front and rear members; welding the side members to the front and rear members.