Preparation method of 650 MPa-grade ultrahigh-strength aluminum alloy thin strip

Abstract

The invention relates to the technical field of metal plate strip machining, in particular to a preparation method of a 650 MPa-grade ultrahigh-strength aluminum alloy thin strip. The preparation method comprises the steps that an Al-Zn-Mg-Cu alloy plate which is hot-rolled to 7.5 mm and contains a rare earth element Er is subjected to two-pass cold rolling and coiled, and a 3.5 mm alloy plate blank coil is obtained; primary annealing treatment is peformed on the alloy plate blank coil, and then four-pass cold rolling is performed to obtain an alloy strip coil with a thickness of 0.5 mm; and finally, solid solution heat treatment and spray quenching are performed, and then T6 aging treatment is performed to obtain the 650 MPa-grade ultrahigh-strength aluminum alloy thin strip. According tothe aluminum alloy thin strip obtained through the method, a cupping test value reaches 6.0 mm before solid solution state aging, when bent in a mold with a fillet of not less than 2 mm for 90 degrees, no cracks occur, and after T6 aging heat treatment, a tensile strength can reach 650-700 MPa, a yield strength can reach 550-620 MPa, and a percentage elongation after fracture can reach 10%-15%.

Description

technical field [0001] The invention relates to the technical field of metal strip processing, in particular to a method for preparing a 650MPa ultra-high-strength aluminum alloy thin strip. Background technique [0002] Ultra-high-strength aluminum alloy sheets have broad application prospects in the fields of automobiles, rail transit, aerospace, engineering equipment, and civil use. They can replace 6xxx and 5xxx series aluminum alloy sheets and strips to make various shell and panel products, which can significantly improve the product quality. Bearing capacity, reduce component weight. [0003] Ultra-high-strength aluminum alloys usually have poor ductility and toughness, and the processing and preparation of their thin strips is very difficult, which severely limits their applications. At present, my country has not realized the mass production of ultra-high-strength aluminum alloy strips below 1mm, the main reason is that the processing technology is difficult to con...

AI Technical Summary

Problems solved by technology

CN111057920A discloses a super-high-strength aluminum alloy and its preparation method. On the basis of Al-Zn-Cu-Mg system, Zr, Ti and Y elements are added, and solution aging treatment is carried out after hot extrusion processing. The strength is higher than 900MPa, The maximum elongation after breaking is 5.6%, but it does not involve the processing method of cold rolling to produce thin strip

CN111020323A discloses a rolling method of ultra-high-strength aluminum alloy sheet material, the Zn content in the alloy is not more than 1%, and the Cu content is relatively high. It can be seen that a certain amount of Zn and Mg alloys are added on the basis of the Al-Cu alloy Elements and hard reinforcements such as TiC, MnO, SiO, ErO, etc., the hot-rolled alloy is solution treated and then cold-rolled, but the specific rolling thickness and final performance indicators are not specified

The aluminum alloy thin strips in the prior art are mainly 1xxx series, 3xxx series, 5xxx series, and 8xxx series aluminum alloy thin strips with low strength properties, and very few 7xxx series ultra-high-strength aluminum alloy thin strips

After annealing of 7xxx ultra-high-strength aluminum alloy sheets, the cold-rolling deformation rate is low, and cracking may occur when the deformation rate reaches 10-20%. It is extremely difficult to obtain ultra-high-strength aluminum alloy thin strips with a thickness of less than 1.0mm