Aluminum alloy plate and process for producing the same

Abstract

The present invention provides an Al-Mg series alloy sheet of high-Mg with improved press formability and homogeneity which can be applied to automobile outer panels and inner panels. This is an Al-Mg series aluminum alloy sheet having 0.5 to 3 mm in thickness cast by twin-roll continuous casting and cold rolled, comprising over 8% but not more than 14% Mg, 1.0% or less Fe, and 0.5% or less Si with the remainder being Al and unavoidable impurities, wherein the mean conductivity of the aluminum alloy sheet is in the range of at least 20 IACS% but less than 26 IACS%, the strength-ductility balance (tensile strength x total elongation) as a material property of the aluminum alloy sheet is 11000 (MPa%) or more, and the homogeneity and press formability of the sheet have been improved.

Description

technical field [0001] The present invention relates to an aluminum alloy plate and a manufacturing method thereof, which is an Al-Mg-based aluminum alloy plate containing high Mg obtained by continuous casting, which has an excellent balance of strength and ductility and excellent formability. Background technique [0002] In recent years, in the field of the body of transport aircraft such as automobiles, fuel efficiency improvement due to weight reduction has been pursued in response to global environmental problems caused by exhaust gas and the like. Therefore, the use of aluminum alloy materials such as rolled plates and extruded profiles, which are lighter in weight, in place of conventionally used steel materials for automobile bodies is increasing. [0003] Among them, the use of Al-Mg-based aluminum for the outer panels (outer panels) and inner panels (inner panels) of automotive panel panels (panel structures) such as cover panels, fenders, roofs, and trunk lids is...

AI Technical Summary

Problems solved by technology

This is because the current twin-roll continuous casting method, as described later, is a casting method in which a lubricant is coated on the rolls. Therefore, depending on the position of the plate, the solidification rate is likely to be insufficient, and the higher the Mg content , the greater the impact on the increase of large-grain segregation and small-grain segregation

Therefore, in the current twin-roll continuous casting method, the Mg content is increased, and there is also a problem that it is difficult to average the strength and ductility balance of the Al-Mg-based Al alloy sheet within the same sheet.

[0017] Therefore, in order to improve the press formability of the above-mentioned actual outer and inner panels of the high-Mg Al-Mg-based Al alloy sheet produced by the twin-roll continuous casting method, only the crystal grains of the above-mentioned Patent Documents 1 and 2 are made finer. , and it is not sufficient to refine the Al-Mg intermetallic compound or reduce the coarse structure