Method of manufacturing lightweight high-strength member

Abstract

The present invention is to manufacture a lightweight high-strength member having desired mechanical properties such as a suspension part of an automobile. The present invention is a method of manufacturing a lightweight high-strength member such as a suspension part of an automobile, and has the steps of pouring the molten metal of an aluminum alloy containing, by weight, 4.0% to 10.5% Si and 0.3% to 1.3% Cu into a mold to cast a preform, and hot-forging the preform by the use of a forging die to form a final formed product.

What is claimed is:  
     
         1 . A method of manufacturing a lightweight high-strength member such as a suspension part for an automobile, the method comprising the steps of: 
 pouring molten metal of an aluminum alloy containing, by weight, 4.0% to 10.5% Si and 0.3% to 1.3% Cu into a mold to cast a preform; and    hot-forging the preform by use of a forging die to form a final formed product.    
     
     
         2 . A method of manufacturing a lightweight high-strength member according to  claim 1 , wherein the molten metal is pressure-cast under a pressure of not less than 39 MPa.  
     
     
         3 . A method of manufacturing a lightweight high-strength member according to  claim 1 , further comprising the steps of subjecting the part after forging to a solution treatment at a temperature of 530 to 545° C. for 4 to 10 hours, a hardening treatment, and an ageing treatment at a temperature of 170 to 180° C. for 6 to 10 hours.  
     
     
         4 . A method of manufacturing a lightweight high-strength member according to  claim 2 , further comprising the steps of subjecting the part after forging to a solution treatment at a temperature of 530 to 545° C. for 4 to 10 hours, a hardening treatment, and an ageing treatment at a temperature of 170 to 180° C. for 6 to 10 hours.