US2022127708A1PendingUtilityA1
Method for producing a sheet or strip from an aluminium alloy, and a sheet, strip or molded part produced thereby
Est. expiryJan 30, 2039(~12.5 yrs left)· nominal 20-yr term from priority
C22F 1/047C22C 21/08C22C 21/06
39
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Claims
Abstract
A method for producing a sheet or strip from an aluminum alloy and a sheet, strip or molded part produced thereby are disclosed. A rough surface and stretcher strain marks can be avoided if the cold-rolled sheet or strip with a particular composition and microstructure is subjected to a heat treatment with a recrystallization annealing and a subsequent accelerated cooling.
Claims
exact text as granted — not AI-modified1 . A method for producing a sheet or strip from an aluminum alloy, comprising:
from 2.0 to 5.5
wt % magnesium (Mg),
from 0.2 to 1.2
wt % manganese (Mn),
optionally
up to 0.45
wt % silicon (Si),
up to 0.55
wt % iron (Fe),
up to 0.35
wt % chromium (Cr),
up to 0.2
wt % titanium (Ti),
up to 0.2
wt % silver (Ag),
up to 4.0
wt % zinc (Zn),
up to 0.8
wt % copper (Cu),
up to 0.8
wt % zirconium (Zr),
up to 0.3
wt % niobium (Nb),
up to 0.25
wt % tantalum (Ta),
up to 0.05
wt % vanadium (V),
and a remainder comprising aluminum and inevitable production-related impurities, with up to at most 0.05 wt % of each and all together totaling at most 0.15 wt %, wherein the method comprises the following steps:
casting a rolling slab;
optional homogenization of the rolling slab;
hot rolling the rolling slab into a hot-rolled sheet or strip;
cold rolling the hot-rolled sheet or strip to a final thickness, optionally with an intermediate annealing of the sheet or strip, wherein the sheet or strip that has been cold-rolled to the final thickness has at least one intermetallic phase with first particles having an average particle size of 5 μm to 10 μm; and
heat treatment of the sheet or strip that has been cold-rolled to the final thickness, including recrystallization annealing with subsequent accelerated cooling and optionally a stabilization of the sheet or strip that has undergone accelerated cooling, wherein the heat-treated sheet or strip has an average crystal grain size D of ≤60 μm and the average crystal grain size D in mm and a number A of first particles per mm 2 in the aluminum alloy satisfy the condition:
√ D*A> 1.8.
2 . The method according to claim 1 , wherein
√ D*A
is >2.
3 . The method according to claim 1 , wherein
the recrystallization annealing takes place at 300° C. or more, and/or the accelerated cooling takes place at a cooling rate of at least 10 K/s, to below 180° C.
4 . The method according to claim 1 , wherein
the rolling slab is solidified by maintaining a cooling rate of <2.5° C./s.
5 . The method according to claim 1 , wherein
the optional homogenization takes place at 450° C. to 550° C. for at least 0.5 h, and/or the hot rolling takes place at 280° C. to 550° C., and/or the cold rolling to the final thickness, after the intermediate annealing, takes place with a degree of rolling reduction of 10% to 65%, and/or the optional intermediate annealing of the sheet or strip takes place at 300° C. to 500° C. and/or the optional stabilization takes place at 80° C. to 120° C. for at least 0.5 h.
6 . The method according to claim 5 , wherein
a product of the degree of rolling reduction in % after the intermediate annealing and the cooling rate in ° C./s satisfies the condition 10≤degree of rolling reduction*cooling rate 50.
7 . The method according to claim 1 , wherein
a primary intermetallic phase has an Al—Mn basis, and is of the Al13(Mn,Fe)6 type or of the A15FeMn3Si2 type or of the Al12Mn type or of the Al6Mn type.
8 . The method according to claim 1 , wherein
the aluminum alloy has
from 4.0 to 5.0
wt % magnesium (Mg) and/or
from 0.2 to 0.5
wt % manganese (Mn) and
optionally
from 2.0 to 4.0
wt % zinc (Zn).
9 . A sheet or strip composed of an aluminum alloy comprising:
from 2.0 to 5.5
wt % magnesium (Mg),
from 0.2 to 1.2
wt % manganese (Mn),
optionally
up to 0.45
wt % silicon (Si),
up to 0.55
wt % iron (Fe),
up to 0.35
wt % chromium (Cr),
up to 0.2
wt % titanium (Ti),
up to 0.2
wt % silver (Ag),
up to 4.0
wt % zinc (Zn),
up to 0.8
wt % copper (Cu),
up to 0.8
wt % zirconium (Zr),
up to 0.3
wt % niobium (Nb),
up to 0.25
wt % tantalum (Ta),
up to 0.05
wt % vanadium (V),
and a remainder comprising aluminum and inevitable production-related impurities, with up to at most 0.05 wt % of each and all together totaling at most 0.15 wt %, wherein the sheet or strip has an average crystal grain size D of ≤60 μm and has at least one intermetallic phase with first particles having an average particle size of 5 μm to 10 μm, and wherein the average crystal grain size D in mm and a number A of first particles per mm 2 in the aluminum alloy satisfy the condition
√ D*A> 1.8,
wherein the sheet or strip has been subjected to a heat treatment, including recrystallization annealing with subsequent accelerated cooling and optionally a stabilization of the sheet or strip that has undergone accelerated cooling.
10 . The sheet or strip according to claim 9 , wherein
√ D*A
is >2.
11 . The sheet or strip according to claim 9 , wherein
the crystal structure has more than 200 dislocations at each first particle.
12 . The sheet or strip according to claim 9 , wherein
the number A of first particles in the aluminum alloy is ≥10 particles/mm.
13 . The sheet or strip according to claim 9 , wherein
a primary intermetallic phase has an Al—Mn basis, and is of the Al13(Mn,Fe)6 type or of the Al15FeMn3Si2 type or of the Al12Mn type or of the Al6Mn type.
14 . The sheet or strip according to claim 9 , wherein
the aluminum alloy has
from 4.0 to 5.0
wt % magnesium (Mg) and/or
from 0.2 to 0.5
wt % manganese (Mn) and
optionally
from 2.0 to 4.0
wt % zinc (Zn).
15 . A molded part, more particularly a vehicle part, preferably a vehicle body part, composed of a sheet-metal-formed sheet or strip according to claim 9 .
16 . A molded vehicle part composed of a sheet-metal-formed sheet or strip according to claim 9 .
17 . A molded vehicle body part, composed of a sheet-metal-formed sheet or strip according to claim 9 .Join the waitlist — get patent alerts
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