Non-Cu-based cast Al alloy and method for heat treatment thereof

Abstract

A non-Cu-based cast Al alloy contains substantially no Cu, and has a tensile strength of 305 MPa or more, a 0.2% yield strength of 220 MPa or more, and an elongation of 10% or more. In the heat treatment of the cast Al alloy, the solution treatment is performed using a fluidized bed 18, and the solution treatment is performed by rapid heating up to the solution treatment temperature in 30 minutes, and maintaining the solution treatment temperature in 3 hours or less. Because this method for heat treatment performs solution treatment at an increased speed of heating-up time, with small deviation of temperature, and at a higher temperature, total time for heat treatment can be shortened drastically in comparison with the conventional method. A non-Cu-based cast Al alloy having well-balanced mechanical properties of tensile strength, yield strength, and elongation can be provided.

1 . to  5 . (Canceled).  
     
     
         6 . A method for heat treatment of a cast Al alloy comprising; 
 subjecting a work piece of the cast Al alloy to solution treatment, and then    subjecting the work piece to aging treatment, to improve mechanical properties of the work piece,    wherein at least said solution treatment is performed by rapidly raising the temperature to the solution treatment temperature within 30 minutes, and maintaining said solution treatment temperature within 3 hours to form the non-Cu-based cast Al alloy that has a tensile strength of 305 MPa or more, a 0.2% yield strength of 220 MPa or more, and an elongation of 10% or more.    
     
     
         7 . A method for heat treatment of a cast Al alloy comprising; 
 subjecting a work piece of the cast Al alloy to solution treatment, and then    subjecting the work piece to aging treatment, to improve mechanical properties of the work piece,    wherein at least said solution treatment is performed by allowing said work piece to be present in a fluidized bed to form the non-Cu-based cast Al alloy that has a tensile strength of 305 MPa or more, a 0.2% yield strength of 220 MPa or more, and an elongation of 10% or more.    
     
     
         8 . The method of heat treatment according to  claim 7 , wherein said aging treatment is performed by allowing said work piece to be present in a fluidized bed.  
     
     
         9 . The method of heat treatment according to  claim 7 , wherein said fluidized bed is formed by the direct blowing of hot air.  
     
     
         10 . The method of heat treatment according to  claim 8 , wherein said fluidized bed is formed by the direct blowing of hot air.