Abstract: According to the invention, in extrusion molding of a control arm of aluminum, control arm is manufactured by a variable curvature extruding process that simultaneously form straight sections and a curved section in extruding a raw material, without pressing forming that is accompanied by solution heat-treatment for forming a carrier fastening end and a bush fastening end at both ends of control arm. Therefore, since the press forming that is required in the extrusion molding of control arm is removed, the manufacturing process is simplified and the manufacturing cost is reduce. Further, the entire extrusion profile cross section of control arm has a double-hollow closed cross section to distribute loads, such that durability of a load-concentrated portion of control arm is increased and the loads can be more effectively distributed.

Abstract: An Al—Si—Mg-based aluminum alloy includes about 1.2 to about 1.4 wt % of Si, about 0.6 to about 0.75 wt % of Mg, about 0.8 to about 1.0 wt % of Sn, and Al and impurities as the balance on the basis of the total weight of the aluminum alloy.

Abstract: According to the invention, in extrusion molding of a control arm of aluminum, control arm is manufactured by a variable curvature extruding process that simultaneously form straight sections and a curved section in extruding a raw material, without pressing forming that is accompanied by solution heat-treatment for forming a carrier fastening end and a bush fastening end at both ends of control arm. Therefore, since the press forming that is required in the extrusion molding of control arm is removed, the manufacturing process is simplified and the manufacturing cost is reduce. Further, the entire extrusion profile cross section of control arm has a double-hollow closed cross section to distribute loads, such that durability of a load-concentrated portion of control arm is increased and the loads can be more effectively distributed.