High strength aluminum alloy casting and method of production of same

Abstract

A high strength aluminum alloy casting obtained by casting an aluminum alloy comprised of 7.5 to 11.5 wt % of Si, 3.8 to 4.8 wt % of Cu, 0.45 to 0.65 wt % of Mg, 0.4 to 0.7 wt % of Fe, 0.35 to 0.45 wt % of Mn, and the balance of Al and not more than 0.2 wt % of unavoidable impurities, wherein this aluminum alloy has 0.1 to 0.3 wt % of Ag added to it or contains 0.1 to 1.0 wt % of at least one element selected from the group of second additive elements comprised of Rb, K, Ba, Sr, Zr, Nb, Ta, V, and Pd and rare earth elements, and a method of production of a high strength aluminum alloy casting comprising the steps of filling a melt of an aluminum alloy in a mold to obtain a casting, taking out the aluminum alloy casting from the mold, solubilizing the high strength aluminum alloy casting by heating in a temperature range of 495 to 505° C. for 2 to 6 hours, quenching the high strength aluminum alloy casting after the solubilization, and age hardening the high strength aluminum alloy casting by heating in a temperature range of 160 to 220° C. for 2 to 6 hours after quenching.

1 . A method of production of a high strength aluminum alloy casting obtained by casting an aluminum alloy comprised of 7.5 to 11.5 wt % of Si, 3.8 to 4.8 wt % of Cu, 0.45 to 0.65 wt % of Mg, 0.4 to 0.7 wt % of Fe, 0.35 to 0.45 wt % of Mn, and the balance of Al and not more than 0.2 wt % of unavoidable impurities, 
 wherein said method of production is a die cast method and further comprises the steps of closing mold halves, pouring aluminum melt into a melt sleeve of a die cast machine, then using an injection plunger to close a melt pouring inlet of the die cast machine and reducing the pressure in the mold to not more than 13.3 kPa and filling a high strength aluminum alloy in the mold after reducing the pressure, and    comprising the steps of:    filling a melt of an aluminum alloy in a mold to obtain a casting,    taking out the aluminum alloy casting from the mold,    solubilizing the high strength aluminum alloy casting by heating in a temperature range of 495 to 505° C. for 2 to 6 hours,    quenching the high strength aluminum alloy casting after the solubilization, and    age hardening the high strength aluminum alloy casting by heating in a temperature range of 160 to 220° C. for 2 to 6 hours after quenching,    wherein this aluminum alloy contains 0.1 to 1.0 wt % of at least one element selected from the group of second additive elements comprised of Rb, K, Ba, Sr, Zr, Nb, Ta, V, and Pd and rare earth elements in order to inhibit casting defects which are attributed to molten hydrogen gas in the alloy casting.    
     
     
         2 . A method of production as set forth in  claim 1 , wherein said method of production further comprises the step of adjusting the atmosphere by blowing in oxygen of a pressure of at least atmospheric pressure.  
     
     
         3 . A method of production as set forth in  claim 1 , wherein said method of production is a die cast method and further comprises the step of closing the mold halves, pouring aluminum melt into the melt sleeve of the die cast machine, then using low speed die casting to fill high strength aluminum alloy into the mold while advancing the injection plunger at a low speed so as to keep air, heat decomposition gas produced from a release agent, etc. from being entrained.  
     
     
         4 . A method of production of a scroll for a compressor of an air-conditioner made from a high strength aluminum alloy casting set forth in  claim 1 , comprising the steps of: 
 reducing the pressure inside the mold to not more than 13.3 kPa and    filling the mold with a high strength aluminum alloy after reduction of pressure for die casting.    
     
     
         5 . A method of production of a scroll for a compressor of an air-conditioner made from a high strength aluminum alloy casting set forth in  claim 1 , comprising the steps of: 
 adjusting the atmosphere by blowing oxygen of a pressure of at least atmospheric pressure into the mold after the step of reducing the pressure inside the mold to not more than 13.3 kPa and    filling the high strength aluminum alloy into the mold for die casting after adjusting the atmosphere.    
     
     
         6 . (canceled)