Method for manufacturing al-zn-mg-cu series aluminum alloy plate, and aluminum alloy plate

Abstract

Disclosed is a method for manufacturing an Al—Zn—Mg—Cu series aluminum alloy plate. The method comprises: (1) preparing an Al—Zn—Mg—Cu series aluminum alloy ingot; (2) sequentially performing homogenization, hot rolling, cold rolling, solid solution quenching and artificial aging on the Al—Zn—Mg—Cu series aluminum alloy ingot to obtain a T6-state aluminum alloy plate; (3) performing heating, warm forming, in-mold quenching, pre-aging and paint baking treatment on the T6-state aluminum alloy plate to obtain a finished aluminum alloy plate. Further disclosed is an Al—Zn—Mg—Cu series aluminum alloy plate, made using the above manufacturing method. The present invention standardizes the production process and process parameters of the Al—Zn—Mg—Cu series aluminum alloy plate, and the Al—Zn—Mg—Cu series aluminum alloy plate prepared by said manufacturing method has high tensile strength, yield strength and elongation, can be applied to automobiles, and has good popularization prospects and application value.

1 . A method for manufacturing an Al—Zn—Mg—Cu series aluminum alloy plate, comprising steps of:
 (1) preparing an Al—Zn—Mg—Cu series aluminum alloy ingot; 
 (2) subjecting the Al—Zn—Mg—Cu series aluminum alloy ingot to homogenization treatment, hot rolling, cold rolling, solid solution quenching treatment, and artificial aging treatment in sequence to obtain a T6-state aluminum alloy plate; 
 (3) subjecting the T6-state aluminum alloy plate to heating, warm forming, die quenching, pre-aging treatment and paint baking treatment to obtain a finished aluminum alloy plate. 
 
     
     
         2 . The method according to  claim 1 , wherein the Al—Zn—Mg—Cu series aluminum alloy ingot comprises the following chemical elements in mass percentages:
 Cu: 1.6-2.2%, Mg: 1.8-2.4%, Zn: 6.0-8.6%, Zr: 0.10-0.16%, 0<Ti≤0.10%, 0<Mn≤0.05%, 0<Cr≤0.04%, and a balance of Al and unavoidable impurities. 
 
     
     
         3 . The method according to  claim 2 , wherein the mass percentages of the chemical elements of the Al—Zn—Mg—Cu series aluminum alloy ingot further satisfy at least one of:
 Cu: 1.8-2.2%, 
 Mg: 2.0-2.4%, 
 Zn: 6.1-7.8%, 
 Zr: 0.10-0.13%. 
 
     
     
         4 . The method according to  claim 1 , wherein the unavoidable impurities in the Al—Zn—Mg—Cu series aluminum alloy ingot include at least one of the following: Si≤0.10%, Fe≤0.15%, and a total amount of other impurity elements≤0.100%. 
     
     
         5 . The method according to  claim 1 , wherein in step (2), a three-stage homogenization process is used for the homogenization treatment, wherein a first stage homogenization treatment is held at a temperature of 418-430° C. for 5-8 hours, a second stage homogenization treatment is held at a temperature of 460-468° C. for 8-12 hours, and a third stage homogenization treatment is held at a temperature of 470-480° C. for 20-24 hours. 
     
     
         6 . The method according to  claim 1 , wherein in step (2), the hot rolling includes steps of: heating the ingot to 430-440° C., holding for 90-120 minutes, and then performing multiple passes of hot rolling, wherein the hot rolling is carried out in longitudinal and transverse directions alternately, a total hot rolling deformation rate is controlled to be ≥85%, and a rolling-end temperature is controlled to be ≥380° C. 
     
     
         7 . The method according to  claim 1 , wherein in step (2), the cold rolling includes steps of: first air cooling a hot-rolled plate to room temperature, and then performing multiple passes of cold rolling with a total cold rolling deformation rate being controlled to be ≥75%. 
     
     
         8 . The method according to  claim 1 , wherein in step (2), a two-stage solution treatment process is used for the solid solution quenching treatment, wherein a first stage solid solution treatment is held at a temperature of 445-450° C. for 20-30 minutes, and a second stage solid solution treatment is held at a temperature of 475-478° C. for 10-20 minutes, followed by direct water quenching. 
     
     
         9 . The method according to  claim 8 , wherein in step (2), a quenching transfer time is controlled to be 10 seconds or less. 
     
     
         10 . The method according to  claim 1 , wherein in step (2), the artificial aging treatment is held at a temperature of 185-205° C. for 30-60 minutes. 
     
     
         11 . The method according to  claim 1 , wherein in step (3), the heating is rapid solid solution heating and includes holding at a temperature of 460-477° C. for 5-10 minutes. 
     
     
         12 . The method according to  claim 1 , wherein in step (3), the pre-aging treatment is held at a temperature of 75-100° C. for 30-60 minutes. 
     
     
         13 . The method according to  claim 1 , wherein in step (3), the paint baking treatment is held at a temperature of 170-190° C. for 20-40 minutes. 
     
     
         14 . An Al—Zn—Mg—Cu series aluminum alloy plate obtained by the method according to  claim 1 . 
     
     
         15 . The Al—Zn—Mg—Cu series aluminum alloy plate according to  claim 14 , wherein its performances satisfy: tensile strength: 610-650 MPa, yield strength: 580-630 MPa, and elongation: ≥15.0%. 
     
     
         16 . The method according to  claim 2 , wherein the content of Ti is 0<Ti≤0.06%. 
     
     
         17 . The method according to  claim 4 , wherein Si≤0.08%, Fe≤0.1%, and a total amount of other impurity elements≤0.030%. 
     
     
         18 . The method according to  claim 11 , wherein the heating is performed by contact heating. 
     
     
         19 . The Al—Zn—Mg—Cu series aluminum alloy plate according to  claim 14 , wherein the Al—Zn—Mg—Cu series aluminum alloy ingot comprises the following chemical elements in mass percentages: Cu: 1.6-2.2%, Mg: 1.8-2.4%, Zn: 6.0-8.6%, Zr: 0.10-0.16%, 0<Ti≤0.10%, 0<Mn≤0.05%, 0<Cr≤0.04%, and a balance of Al and unavoidable impurities. 
     
     
         20 . The Al—Zn—Mg—Cu series aluminum alloy plate according to  claim 14 , wherein the unavoidable impurities in the Al—Zn—Mg—Cu series aluminum alloy ingot include at least one of the following: Si≤0.10%, Fe≤0.15%, and a total amount of other impurity elements≤0.100%.