US2004047759A1PendingUtilityA1
Aluminium alloy for lithographic sheet
Priority: Dec 11, 2000Filed: Dec 11, 2001Published: Mar 11, 2004
Est. expiryDec 11, 2020(expired)· nominal 20-yr term from priority
C22C 21/06C22F 1/047C22F 1/04B41N 1/083C22C 21/00
38
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Claims
Abstract
The invention discloses an Al alloy suitable for processing into a lithographic sheet, the alloy having a composition in wt %: Mg 0.05 to 0.30, Mn 0.05 to 0.25, Fe 0.11 to 0.40, Si up to 0.25, Ti up to 0.03, B up to 0.01, Cu up to 0.01, Cr up to 0.03, Zn up to 0.15, unavoidable impurities up to 0.05 each, 0.15 total Al balance. Also disclosed is a method of processing the Al alloy.
Claims
exact text as granted — not AI-modified1 . An Al alloy suitable for processing into a lithographic sheet, the alloy having a composition in wt %:
Mg
0.05 to 0.30
Mn
0.05 to 0.25
Fe
0.11 to 0.40
Si
up to 0.25
Ti
up to 0.03
B
up to 0.01
Cu
up to 0.01
Cr
up to 0.03
Zn
up to 0.15
unavoidable impurities up to 0.05 each, 0.15 total Al balance:
2 . An alloy according to claim 1 , wherein Mg is present in an amount of 0.06 to 0.30 wt %.
3 . An alloy according to claim 2 , wherein Mg is present in an amount of 0.10 to 0.30 wt %.
4 . An alloy according to any preceding claim, wherein Mn is present in an amount of 0.05 to 0.20 wt %.
5 . An alloy according to any preceding claim, wherein up to 0.028 wt % free Ti is present.
6 . An alloy according to any preceding claim, wherein Ti is present in a total amount up to 0.015 wt %.
7 . An alloy according to claim 6 , wherein Ti is present in a total amount up to 0.010 wt %.
8 . An alloy according to any preceding claim, wherein up to 0.019 wt % Zr is present.
9 . An alloy according to claim 8 , wherein up to 0.005 wt % Zr is present.
10 . An alloy according to any preceding claim, wherein there is no deliberate addition of Zr.
11 . An alloy according to any preceding claim, wherein Fe is present in an amount of about 0.20 to 0.40 wt %.
12 . An alloy according to any preceding claim, wherein Si is present in an amount of about 0.05 to 0.15 wt %.
13 . An alloy according to any preceding claim, wherein Si is present in an amount of 0.09 to 0.15 wt %.
14 . An alloy according to any preceding claim, wherein Zn is present in an amount of 0.05 wt %.
15 . An alloy according to any one of claims 1 to 13 , wherein Zn is present in an amount of 0.01 to 0.1 wt %.
16 . An alloy according to claim 15 , wherein Zn is present in an amount of from 0.015 to 0.06 wt %.
17 . An alloy according to claim 16 , wherein Zn is present in an amount of from about 0.02 to about 0.05 wt %.
18 . An Al alloy according to claim 1 having a composition in wt %:
Mg
0.10
Mn
0.10
Zn
0.02 to 0.05
Fe
0.30
Si
0.08
Ti
0.006
Unavoidable impurities up to 0.05 each, 0.15 total Al balance.
19 . A lithographic sheet formed from the alloy of any preceding claim.
20 . A lithographic sheet according to claim 19 , wherein Ti is present in an amount sufficient to enable the sheet to be capable of being electrograined in nitric acid.
21 . A DC cast ingot comprising an alloy of any one of claims 1 to 13 .
22 . A method of processing an Al alloy according to any one of claims 1 to 13 , which method comprises the steps of: casting, optional homogenising, optional hot rolling, cold rolling, optional interannealing.
23 . A method according to claim 22 , wherein the casting step is carried out by DC casting.
24 . A method according to claim 22 or 23 , wherein the homogenisation step is carried out by heating the cast alloy to a temperature of 550 to 610° C. for 1 to 10 hours and subsequently cooling to a hot rolling temperature of between 450 and 550° C.
25 . A method according to claim 22 or 23 , wherein the homogenisation step is carried out by ramped heating of the cast alloy to a temperature of 450 to 550° C. for 1 to 16 hours and subsequently hot rolling at that temperature.
26 . A method according to any one of claims 22 to 25 , which does not comprise the optional interannealing step.
27 . A method according to any one of claims 22 to 26 , wherein the interannealing is batch interannealing.
28 . A method according to claim 27 , wherein the interannealing is carried out at 300 to 500° C. for 1 to 5 hours.
29 . A method according to any one of claims 22 to 26 , wherein the interannealing is continuous interannealing.
30 . A method according to claim 29 , wherein the continuous interannealing is carried out at 450 to 600° C. for less than 10 minutes.
31 . A method according to any one of claims 22 to 30 , further comprising the step of electrograining.
32 . A method according to claim 31 , wherein the alloy is electrograined in hydrochloric acid.
33 . A method according to claim 31 , wherein the alloy is electrograined in nitric acid.
34 . A method according to claim 31 , wherein the alloy is capable of being electrograined in both hydrochloric and nitric acids.
35 . A method of forming a lithographic sheet comprising electrograining an aluminium metal sheet in a nitric acid electrolyte until a total charge input of above 82 kC/m 2 is applied, wherein the surface of the lithographic sheet comprises a pitted structure, and wherein the metal sheet is formed of an alloy according to any one of claims 1 to 18 .
36 . A method according to claim 35 , wherein a total charge input of about 87 kC/m 2 is applied.Cited by (0)
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