Blister-free aluminum forgings and method of making the same

Abstract

An aluminum alloy, which is more resistant to high temperature oxidation-type blistering, comprises: about 0.65-0.9 wt. % silicon, about 4-4.6 wt. % copper, about 0.6-0.9 wt. % manganese, about 0.35-0.55 wt. % magnesium, up to about 0.14 wt. % iron and a balance of aluminum, incidental elements and impurities. By reducing iron content, the invention has reduced scrap rates in some forging part lines to 0% . An improvement in fracture toughness performance was also observed. In an additional aspect, a forged structural part, and a method of making a forged structural part, are provided.

1 . A forged structural part having an improved resistance to high temperature oxidation, said structural part made from an alloy consisting essentially of: about 0.65-0.9 wt % silicon, about 4.0-4.6 wt % copper, about 0.6-0.9 wt % manganese, about 0.35-0.55 wt % magnesium, up to about 0.15 wt % iron, the balance being aluminum and incidental elements and impurities.  
     
     
         2 . The forged structural part of  claim 1 , wherein said part has a minimum tensile yield strength of at least about 56 ksi.  
     
     
         3 . The forged structural part of  claim 1 , wherein said part has an ultimate strength of at least about 65 ksi.  
     
     
         4 . The forged structural part of  claim 1 , wherein said part has an elongation of at least about 6%.  
     
     
         5 . The forged structural part of  claim 1 , wherein said part has been artificially aged to a temper of T6.  
     
     
         6 . The forged structural part of  claim 1 , which contains about 0.7-0.85 wt % silicon.  
     
     
         7 . The forged structural part of  claim 1 , which contains about 4.1-4.5 wt % copper.  
     
     
         8 . The forged structural part of  claim 1 , which contains about 0.65-0.85 wt % manganese.  
     
     
         9 . The forged structural part of  claim 1 , which contains about 0.4-0.5 wt % magnesium.  
     
     
         10 . The forged structural part of  claim 1 , which contains about 0.14 wt % iron or less.  
     
     
         11 . The forged structural part of  claim 1 , wherein said part is a vehicle wheel.  
     
     
         12 . The forged structural part of  claim 1 , wherein said part is an aircraft wheel.  
     
     
         13 . The forged structural part of  claim 1 , wherein said part is an aircraft brake component.  
     
     
         14 . The forged structural part of  claim 1 , wherein said part is a vehicle brake component.  
     
     
         15 . A method of making a forged structural part having improved resistance to high temperature oxidation, said method comprising: 
 providing a cast billet having an alloy composition consisting essentially of: about 0.65-0.9 wt % silicon, about 4.0-4.6 wt % copper, about 0.6-0.9 wt % manganese, about 0.35-0.55 wt % magnesium, up to about 0.15 wt % iron, the balance being aluminum and incidental elements and impurities;    heating said billet to a forging temperature and hot working said heated billet to create a forged part;    solution heat treating said forged part; and    quenching said forged part.    
     
     
         16 . The method of  claim 15 , wherein said forged part is artificially aged to a T6 temper.  
     
     
         17 . The method of  claim 16 , wherein said artificial aging is carried out at a temperature of about 325°-375° F.  
     
     
         18 . The method of  claim 15 , wherein said heating and hot working are carried out more than once.  
     
     
         19 . The method of  claim 15 , wherein said forging temperature is about 700°-900° F.  
     
     
         20 . The method of  claim 15 , wherein said solution heat treatment is carried out at a temperature of about 925°-945° F.  
     
     
         21 . The method of  claim 15 , wherein said forged part has a minimum tensile yield strength of at least about 56 ksi.  
     
     
         22 . The method of  claim 15 , wherein said forged part has an ultimate strength of at least about 65 ksi.  
     
     
         23 . The method of  claim 15 , wherein said forged part has an elongation of at least about 6%.  
     
     
         24 . The method of  claim 15 , wherein said forged part contains about 0.7-0.85 wt % silicon.  
     
     
         25 . The method of  claim 15 , wherein said forged part contains about 4.1-4.5 wt % copper.  
     
     
         26 . The method of  claim 15 , wherein said forged part contains about 0.65-0.85 wt % manganese.  
     
     
         27 . The method of  claim 15 , wherein said forged part contains about 0.4-0.5 wt % magnesium.  
     
     
         28 . The method of  claim 15 , wherein said forged part contains about 0.14 wt % iron or less.  
     
     
         29 . The method of  claim 15 , wherein said forged part is a vehicle wheel.  
     
     
         30 . The method of  claim 15 , wherein said forged part is an aircraft wheel.  
     
     
         31 . The method of  claim 15 , wherein said forged part is an aircraft brake component.  
     
     
         32 . The method of  claim 15 , wherein said forged part is a vehicle brake component.