PRODUCTION OF ALUMINUM-ZINC-MAGNESIUM SERIES ALUMINUM ALLOY EXCELLENT IN EXTRUDABILITY AND THE SERIES ALUMINUM ALLOY EXTRUDED MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide a method for producing an Al alloy for extrusion and an Al alloy extruded material in which, at the time of extruding an Al-Zn-Mg series aluminum alloy, even in the case that the extruding rate is speeded up, the seizure of the aluminum alloy is prevented, and good surface properties can be secured. ;SOLUTION: As for the structure of an Al-Zn-Mg series aluminum alloy before extrusion, among precipitates in the aluminum alloy matrix, MgZn₂ precipitates are allowed to enter into solid solution in the aluminum alloy, or the average size of the MgZn₂ precipitates is regulated to 0.01 μm, and furthermore, the average size of Al-transition metal series precipitates is regulated to 0.2 μm. Moreover, for obtaining this structure, at the time of subjecting the Al-Zn-Mg series aluminum alloy to homogenizing heat treatment after casting, the heat treating temp. is regulated to the range of 430 to 480°C, and cooling after the heat treatment is executed by water cooling.;COPYRIGHT: (C)1999,JPO