Aluminum alloy structural components, starting material and method of manufacture

Abstract

The current disclosure describes a process for producing starting material for forged structural components made of aluminum. The process comprises the production of an aluminum alloy with 0.7 to 1.8 wt.-% silicon, 0.5 to 1.4 wt.-% magnesium, 0.3 to 1.2 wt.-% manganese, 0.005 to 0.5 wt.-% zirconium, 0.001 to 0.1 wt.-% titanium and no more than 0.3 wt.-% iron by means of direct quenching continuous casting. In this process, the melt is guided in such a way that it does not come into contact with a solid surface during quenching.

What is claimed is: 
     
         1 . A method for the production of a starting material for forged structural components made of aluminum, comprising:
 preparation of a melt with the components:
 0.7 to 1.8 wt.-% of silicon, 
 0.5 to 1.4 wt.-% of magnesium, 
 0.3 to 1.2 wt.-% of manganese, 
 0.005 to 0.2 wt.-% of zirconium, 
 0.01 to 0.05 wt.-% titanium, 
 0.08 to 0.3 wt.-% iron, 
 0.08 to 0.2 wt.-% chromium, 
 no more than 0.04 wt.-% zinc, 
 no more than 0.1 wt.-% copper, and 
 residual aluminum and unavoidable impurities, 
 wherein the ratio of silicon to magnesium is at least 1:0.8, and 
 the melt contains less than 0.5 ml H 2  per 100 g aluminum; and 
   continuous in casting of the aluminum alloy, wherein the molten metal is guided in such a way that it has no contact with a solid surface during solidification.   
     
     
         2 . The method according to  claim 1 , wherein the production of the aluminum alloy further comprises adding a pre-alloy containing titanium and boron for grain refinement, wherein the pre-alloy is preferably added to the melt immediately before it passes through a water-cooled annular mold. 
     
     
         3 . The method according to  claim 2 , wherein the aluminum master alloy contains 4.5 to 5.5 wt. % titanium and 0.8 to 1.2 wt. % boron and the remainder aluminum and unavoidable impurities. 
     
     
         4 . The method according to  claim 1 , in which a bar with an electrical conductivity of between 16 MS/m and 18 MS/m is produced by continuous casting. 
     
     
         5 . The method according to  claim 1 , wherein the weight ratio of titanium to zirconium (Ti:Zr) in the aluminum alloy is between 1:4 and 1:6. 
     
     
         6 . The method according to  claim 1 , wherein the weight ratio of iron to chromium to manganese (Fe:Cr:Mn) in the aluminum alloy is at least approximately 1:1:4. 
     
     
         7 . The method according to  claim 1 , wherein the aluminum alloy contains between 0.05 and 0.3 wt.-% of one or more of the rare earth elements to form further finely dispersed dispersoids. 
     
     
         8 . The method according to  claim 1 , wherein the weight ratio of silicon to magnesium (Si:Mg) in the aluminum alloy is between 1:0.7 and 1:0.8. 
     
     
         9 . The method according to  claim 1 , wherein, during solidification of the melt during continuous casting, contact of the melt and a solidified surface layer with a solid surface of the mold is prevented and liquid cooling of the melt is effected during passage through a mold. 
     
     
         10 . The method according to  claim 9 , wherein the melt is liquid-cooled during its passage through the mold in such a way that the cooling rate of the solidifying aluminum alloy is greater than 25 Kelvin per second. 
     
     
         11 . The method according to  claim 9 , wherein the melt is exposed to an oxygen-containing gas mixture during the passage through the mold before and during the solidification of the surface layer. 
     
     
         12 . A method for producing a structural component, in which the starting material produced by means of the method of  claim 1  is hot-formed into a structural component immediately after continuous casting, without a treatment for homogenizing the starting material taking place between the continuous casting and the hot forming. 
     
     
         13 . The method for producing a structural component according to  claim 12 , comprising artificial aging and subsequent air cooling of the hot-formed structural component. 
     
     
         14 . The method according to  claim 13 , in which the artificial aging takes place for 2 hours to 7 hours at 180° C. to 210° C. 
     
     
         15 . Use of a pre-material produced by the method of  claim 1  for the extrusion of forging pre-material for the automotive industry. 
     
     
         16 . Use of a starting material produced by the method of  claim 1  for forging components for the automotive industry. 
     
     
         17 . The method of  claim 1 , wherein the melt comprises:
 1.2 to 1.4 wt. % of silicon;   0.8 to 1.2 wt. % of magnesium;   0.4 to 0.8 wt. % of manganese;   0.05 to 0.2 wt. % of zirconium; and   no more than 0.02 wt. % copper.   
     
     
         18 . The method of  claim 1 , wherein the melt contains less than 0.25 ml H 2  per 100 g aluminum. 
     
     
         19 . The method of  claim 1 , wherein at least one of:
 the weight ratio of titanium to zirconium (Ti:Zr) in the aluminum alloy is at least approximately 1:5; and   the weight ratio of silicon to magnesium (Si:Mg) in the aluminum alloy is at least approximately 1:0.75.   
     
     
         20 . The method of  claim 7 , wherein the rare earth elements comprise one or more of Sc, Er, La, Ce, Y and/or Yb.