6000-series aluminum alloy sheet manufacturing method and aluminum alloy sheet

Abstract

Disclosed are a 6000-series aluminum alloy sheet having high formability, high flangeability and few roping line defects, and a manufacturing method therefor. The sheet has an average grain size of 20-32 μm, a recrystallization texture density of 6.5-10.0, a cubic texture component content of less than or equal to 8%, and a Gaussian texture component content of less than or equal to 7%. The method comprises: (1) homogenizing a cast ingot, the temperature of homogenization being 530-580° C.; (2) directly performing hot rough rolling, hot finish rolling, and hot final rolling and coiling on the homogenized cast ingot, controlling the initial rolling temperature of the hot finish rolling to be 400-480° C., and controlling the temperature of the hot final rolling and coiling to be above 250° C.; (3) cold rolling: controlling the total deformation of the cold rolling to be 50-85%; (4) solution treatment; and (5) performing pre-aging treatment, and then performing air cooling, so as to obtain the 6000-series aluminum alloy sheet.

1 . A 6000 series aluminum alloy sheet, wherein the 6000 series aluminum alloy sheet has an average grain size of 20˜32 μm, a recrystallization texture density of 6.5˜10.0, a cubic texture component content of ≤8%, and a Gaussian texture component content of ≤7%. 
     
     
         2 . The 6000 series aluminum alloy sheet of  claim 1 , wherein the 6000 series aluminum alloy sheet has a tensile strength of ≥210 MPa, a yield strength of ≥104 MPa, and an elongation of 24%. 
     
     
         3 . The 6000 series aluminum alloy sheet of  claim 1 , wherein the 6000 series aluminum alloy sheet has a plastic strain ratio r of ≥0.68, a plane anisotropy index Δr of ≤0.10, a flanging grade rated as 1 and a roping grade rated as 1. 
     
     
         4 . The 6000 series aluminum alloy sheet of  claim 3 , wherein the 6000 series aluminum alloy sheet has a plastic strain ratio r of ≥0.70, r≥0.72, or r≥0.74. 
     
     
         5 . The 6000 series aluminum alloy sheet of  claim 3 , wherein the 6000 series aluminum alloy sheet has a plane anisotropy index Δr of ≤0.08, ≤0.06, or ≤0.04. 
     
     
         6 . The 6000 series aluminum alloy sheet of  claim 1 , wherein, by mass percentage, the 6000 series aluminum alloy sheet contains: Si: 0.3˜1.5%, Fe: 0.05˜0.5%, Cu: 0.02˜1.1%, Mg: 0.35˜1.2%, Zn: ≤0.8%, Mn: ≤0.8%, Cr: ≤0.35%, Ti: ≤0.15%, V: ≤0.20%, with a balance of Al and unavoidable impurities. 
     
     
         7 . A manufacturing method of the 6000 series aluminum alloy sheet having high formability, high flanging performance and low roping defects at the same time, wherein it comprises the following steps:
 (1) subjecting a cast ingot to a homogenization treatment, wherein the temperature of the homogenization treatment is 530˜580° C.;   (2) subjecting the homogenized ingot to hot rough rolling, hot finish rolling and hot final rolling and coiling directly, wherein the rolling-start temperature of hot finish rolling is controlled to be 400˜480° C., and the temperature of hot final rolling and coiling is controlled to be 250° C. or higher;   (3) cold rolling: the total deformation rate of cold rolling is controlled to be 50-85%, so as to obtain a cold rolled plate having an average size of Mg 2 Si precipitate phase of 1.3˜1.7 μm, and an areal density of Mg 2 Si precipitate phase of ≥55000 pieces/mm 2 ;   (4) solid solution treatment;   (5) pre-aging treatment, followed by air cooling, to obtain a 6000 series aluminum alloy sheet.   
     
     
         8 . The manufacturing method of the 6000 series aluminum alloy sheet of  claim 7 , wherein in step (2), the temperature of hot final rolling and coiling is 250˜340° C.; in step (3), intermediate annealing is carried out before cold rolling: the temperature of intermediate annealing is controlled to be 350˜430° C., and the holding time is 1˜4h, and then the sheet is cooled to room temperature in furnace; or if the temperature of hot final rolling and coiling is higher than 340° C., the step (3) is directly carried out without intermediate annealing. 
     
     
         9 . The manufacturing method of the 6000 series aluminum alloy sheet of  claim 7 , wherein in step (1), the holding time of the homogenization treatment is 6˜16h; and/or
 in step (2), the hot rough rolling temperature is controlled to be 530˜570° C.; and/or the total deformation rate of hot rough rolling is greater than 70%; and/or the total deformation rate of hot finish rolling is greater than 80%; and/or 
 in step (3), the total deformation rate of cold rolling is 60˜85%; and/or 
 in step (4), the solid solution treatment temperature is 550˜570° C., the heating rate of solid solution is 15˜30° C./s, the holding time of solid solution treatment is 1˜5 min, and the quenching method is water cooling. 
 
     
     
         10 .- 12 . (canceled) 
     
     
         13 . The manufacturing method of the 6000 series aluminum alloy sheet of  claim 7 , wherein in step (5), the pre-aging treatment is carried out immediately within 3 min after the end of step (4); and/or the pre-aging treatment is carried out by raising the temperature to 80˜100° C. and then slowly reducing from 80˜100° C. to room temperature with a cooling rate of 1˜4° C./h. 
     
     
         14 . The manufacturing method of the 6000 series aluminum alloy sheet of  claim 7 , wherein the 6000 series aluminum alloy sheet is the 6000 series aluminum alloy sheet has an average grain size of 20˜32 μm, a recrystallization texture density of 6.5˜10.0, a cubic texture component content of ≤8%, and a Gaussian texture component content of ≤7%. 
     
     
         15 . A 6000 series aluminum alloy sheet prepared by the manufacturing method of  claim 8 . 
     
     
         16 . The 6000 series aluminum alloy sheet of  claim 6 , wherein, by mass percentage, the element composition of the aluminum alloy sheet is as follows: Mg: 0.4˜0.7%, Si: 0.5˜0.8%, Fe: 0.1˜0.3%, Mn: 0.05˜0.15%, Cu: 0.05˜0.3%, Zn: ≤0.05%, V: ≤0.05%, Cr: ≤0.05%, with a balance of Al and unavoidable impurities. 
     
     
         17 . The 6000 series aluminum alloy sheet of  claim 2 , wherein the 6000 series aluminum alloy sheet has a plastic strain ratio r of ≥0.68, a plane anisotropy index Δr of ≤0.10, a flanging grade rated as 1 and a roping grade rated as 1. 
     
     
         18 . The manufacturing method of the 6000 series aluminum alloy sheet of  claim 7 , wherein:
 in step (1), the temperature of the homogenization treatment is 550˜570° C., and/or   in step (2) the rolling-start temperature of hot finish rolling is controlled to be 440˜480° C.   
     
     
         19 . The manufacturing method of the 6000 series aluminum alloy sheet of  claim 8 , wherein the heating rate of intermediate annealing is 13˜17° C./h, the cooling rate of intermediate annealing is 12˜15° C./h. 
     
     
         20 . The manufacturing method of the 6000 series aluminum alloy sheet of  claim 7 , wherein:
 the 6000 series aluminum alloy sheet has a tensile strength of ≥210 MPa, a yield strength of ≥104 MPa, and an elongation of ≥24%; and/or   the 6000 series aluminum alloy sheet has a plastic strain ratio r of ≥0.68, a plane anisotropy index Δr of ≤0.10, a flanging grade rated as 1 and a roping grade rated as 1.   
     
     
         21 . The manufacturing method of the 6000 series aluminum alloy sheet of  claim 7 , wherein, by mass percentage, the 6000 series aluminum alloy sheet contains: Si: 0.3˜1.5%, Fe: 0.05˜0.5%, Cu: 0.02˜1.1%, Mg: 0.35˜1.2%, Zn: ≤0.8%, Mn: ≤0.8%, Cr: ≤0.35%, Ti: ≤0.15%, V: ≤0.20%, with a balance of Al and unavoidable impurities. 
     
     
         22 . The manufacturing method of the 6000 series aluminum alloy sheet of  claim 7 , wherein, the element composition of the aluminum alloy sheet is as follows: Mg: 0.4˜0.7%, Si: 0.5˜0.8%, Fe: 0.1˜0.3%, Mn: 0.05˜0.15%, Cu: 0.05˜0.3%, Zn: ≤0.05%, V: ≤0.05%, Cr: ≤0.05%, with a balance of Al and unavoidable impurities. 
     
     
         23 . The 6000 series aluminum alloy sheet according to  claim 15 , wherein the 6000 series aluminum alloy sheet has an average grain size of 20˜32 μm, a recrystallization texture density of 6.5˜10.0, a cubic texture component content of ≤8%, and a Gaussian texture component content of ≤7%, optionally, the 6000 series aluminum alloy sheet also satisfies the following performances: a tensile strength of ≥210 MPa, a yield strength of ≥104 MPa, an elongation of ≥24%; and a plastic strain ratio r of ≥0.68, a plane anisotropy index Δr of ≤0.10, a flanging grade rated as 1; a roping grade rated as 1.