PROBLEM TO BE SOLVED: To provide a 7,000 series aluminum extruded material which has excellent SCC resistance by optimizing a potential difference between the one in grains and the one on grain boundaries in a 7,000 series aluminum extruded material.;SOLUTION: The temperature of an extruded material directly after extrusion from an extrusion die lies in the range of 580 to 660°C, thereafter, cooling is performed at a cooling rate of 20 to 50°C/min until the temperature of the extruded material reaches ≤100°C, and precipitates with a grain diameter of 1 to 15 nm are present in the crystal grains of the metallic structure by 1,000 to 10,000 pieces/μm2 by observation measurement using a transmission electron microscope.;COPYRIGHT: (C)2011,JPO&INPIT
展开▼
