Cast aluminum alloy for forging, and aluminum cast-forged product and method of manufacturing the same

Abstract

There is disclosed a cast-forged product of an aluminum alloy consisting essentially of: 0.6 to 1.8 wt % of silicon; 0.6 to 1.8 wt % of magnesium; 0.8 wt % or less of copper; 0.2 to 1.0 wt % of manganese; 0.25 wt % or less of chromium; 0.0 to 0.15 wt % of titanium; and unavoidably contained impurities. When the product is used as various parts for automobiles formed of aluminum, such as suspension parts, frames, and parts for engines, the product is more superior in mechanical properties such as a tensile strength, proof stress, and elongation, and can be manufactured with a low cost.

What is claimed is:  
     
         1 . An aluminum alloy consisting essentially of: 0.6 to 1.8 wt % of silicon; 0.6 to 1.8 wt % of magnesium; 0.8 wt % or less of copper; 0.2 to 1.0 wt % of manganese; 0.25 wt % or less of chromium; 0.0 to 0.15 wt % of titanium; and unavoidably contained impurities.  
     
     
         2 . A use of an aluminum alloy in manufacturing an aluminum cast-forged product, wherein a preformed material is cast from the aluminum alloy consisting essentially of 0.6 to 1.8 wt % of silicon, 0.6 to 1.8 wt % of magnesium, 0.8 wt % or less of copper, 0.2 to 1.0 wt % of manganese, 0.25 wt % or less of chromium, 0.0 to 0.15 wt % of titanium, and unavoidably contained impurities, and the preformed material is forged to manufacture an aluminum cast-forged product.  
     
     
         3 . The use in manufacturing an aluminum cast-forged product according to  claim 2 , wherein the preformed material has a shape indicating a forging ratio of 18 to 60%, assuming that the shape of a final product is 100%.  
     
     
         4 . The use in manufacturing an aluminum cast-forged product according to  claim 2 , wherein the aluminum cast-forged product is a suspension part for a vehicle, a frame for the vehicle, or a part for an engine.  
     
     
         5 . The use in manufacturing an aluminum cast-forged product according to  claim 3 , wherein an aluminum cast-forged product is a suspension part for a vehicle, a frame for the vehicle, or a part for an engine.  
     
     
         6 . A method of manufacturing an aluminum cast-forged product consisting essentially of 0.6 to 1.8 wt % of silicon, 0.6 to 1.8 wt % of magnesium, 0.8 wt % or less of copper, 0.2 to 1.0 wt % of manganese, 0.25 wt % or less of chromium, 0.0 to 0.15 wt % of titanium, and unavoidable impurities, the method including: 
 a melting step of melting an aluminum alloy consisting essentially of 0.6 to 1.8 wt % of silicon, 0.6 to 1.8 wt % of magnesium, 0.8 wt % or less of copper, 0.2 to 1.0 wt % of manganese, 0.25 wt % or less of chromium, 0.0 to 0.15 wt % of titanium, and the unavoidable impurities at about 680 to 780° C. to obtain a molten metal;    a casting step of casting the obtained molten metal at a mold temperature of about 60 to 150° C. to obtain a preformed material which is a raw material for forging;    a rough forging step of heating the raw material for forging to a surface temperature at about 380° C. to a melting point or less and forging the raw material to obtain a roughly forged material;    a finish forging step of heating the roughly forged material to a surface temperature at about 380° C. to the melting point or less and forging the roughly forged material to obtain a finish forged material; and    a clipping flash step of removing flash from the finish forged material to obtain a final product.    
     
     
         7 . The method according to  claim 6 , wherein the aluminum alloy includes the flash generated at the time of the forging as a portion of a raw material.  
     
     
         8 . The method according to  claim 7 , wherein a forging ratio of the shape of a preformed material is in a range of 18 to 60%, assuming that the shape of a final product is 100%.  
     
     
         9 . A suspension part for a vehicle, a frame for the vehicle, or a part for an engine prepared by a method of manufacturing an aluminum cast-forged product consisting essentially of 0.6 to 1.8 wt % of silicon, 0.6 to 1.8 wt % of magnesium, 0.8 wt % or less of copper, 0.2 to 1.0 wt % of manganese, 0.25 wt % or less of chromium, 0.0 to 0.15 wt % of titanium, and unavoidable impurities, the method including: 
 a melting step of melting an aluminum alloy consisting essentially of 0.6 to 1.8 wt % of silicon, 0.6 to 1.8 wt % of magnesium, 0.8 wt % or less of copper, 0.2 to 1.0 wt % of manganese, 0.25 wt % or less of chromium, 0.0 to 0.15 wt % of titanium, and the unavoidable impurities at about 680 to 780° C. to obtain a molten metal;    a casting step of casting the obtained molten metal at a mold temperature of about 60 to 150° C. to obtain a preformed material which is a raw material for forging;    a rough forging step of heating the raw material for forging to a surface temperature at about 380° C. to a melting point or less and forging the raw material to obtain a roughly forged material;    a finish forging step of heating the roughly forged material to a surface temperature at about 380° C. to the melting point or less and forging the roughly forged material to obtain a finish forged material; and    a clipping flash step of removing flash from the finish forged material to obtain a final product.    
     
     
         10 . The suspension part for the vehicle, the frame for the vehicle, or the part for the engine according to  claim 9 , wherein the aluminum alloy includes flash generated at the time of the forging as a portion of a raw material.  
     
     
         11 . The suspension part for the vehicle, the frame for the vehicle, or the part for the engine according to  claim 9 , wherein a forging ratio of the shape of the preformed material is in a range of 18 to 60%, assuming that the shape of the final product is 100%.  
     
     
         12 . The suspension part for the vehicle, the frame for the vehicle, or the part for the engine according to  claim 9 , having mechanical properties such as a tensile strength of 320 MPa or more, a proof stress of 280 MPa or more, and an elongation of 10% or more.  
     
     
         13 . The suspension part for the vehicle, the frame for the vehicle, or the part for the engine according to  claim 10 , having mechanical properties such as a tensile strength of 320 MPa or more, a proof stress of 280 MPa or more, and an elongation of 10% or more.  
     
     
         14 . The suspension part for the vehicle, the frame for the vehicle, or the part for the engine according to  claim 11 , having mechanical properties such as a tensile strength of 320 MPa or more, a proof stress of 280 MPa or more, and an elongation of 10% or more.