Aluminum-alloy, fin material and manufacturing method thereof
An aluminum-alloy, fin material is composed of a brazing sheet containing a core material and filler material(s) disposed on both sides of the core material. The core material is an aluminum alloy containing 0.02-0.80 mass % Si, 0.02-0.80 mass % Fe, and 0.8-2.0 mass % Mn. The core material has a crystalline-aggregate structure in which: the orientation density of one or more of brass orientation, copper orientation, and S orientation is 20 times or more that or those of a randomly oriented sample; and the orientation densities of cube orientation, CR orientation, and P orientation are each 10 times or less than those of the randomly oriented sample. The filler material(s) is (are) composed of an Al—Si series alloy that contains 6.0-13.0 mass % Si and 0.02-0.80 mass % Fe. The clad percentage of filler material(s) is 6-16% of the total thickness of the brazing sheet.
1. An aluminum-alloy, fin material composed of a brazing sheet that comprises a core material and either a first filler material disposed on first and second surfaces of the core material or the first filler material disposed on the first surface of the core material and a second filler material disposed on the second surface of the core material, wherein:
the core material has:
an aluminum alloy composition that contains Si: 0.02 mass % or more and 0.80 mass % or less, Fe: 0.02 mass % or more and 0.80 mass % or less, and Mn: 0.8 mass % or more and 2.0 mass % or less; and
a crystalline-aggregate structure in which: the orientation density of one or more crystal orientations selected from the group consisting of brass orientation, copper orientation, and S orientation is 20 times or more that or those of a randomly oriented sample; and the orientation densities of cube orientation, CR orientation, and P orientation are each 10 times or less than those of the randomly oriented sample;
the first and second filler materials are each composed of an Al—Si series alloy that contains Si: 6.0 mass % or more and 13.0 mass % or less and Fe: 0.02 mass % or more and 0.80 mass % or less; and
the clad percentage of each of the first and second filler materials is 6% or more and 16% or less of a total thickness of the brazing sheet.
2. The aluminum-alloy, fin material according to claim 1 , wherein the aluminum alloy composition of the core material further contains Zn: 0.3 mass % or more and 3.0 mass % or less.
3. The aluminum-alloy, fin material according to claim 1 , wherein the Al—Si series alloy that constitutes the first and second filler materials further contains Sr: 0.005 mass % or more and 0.050 mass % or less.
4. A method of manufacturing the aluminum-alloy, fin material according to claim 1 , comprising:
preparing by casting: a core-material slab having an aluminum alloy composition that contains Si: 0.02 mass % or more and 0.80 mass % or less, Fe: 0.02 mass % or more and 0.80 mass % or less, and Mn: 0.8 mass % or more and 2.0 mass % or less; and either only a first filler-material slab or first and second filler-material slabs each composed of an Al—Si series alloy that contains Si: 6.0 mass % or more and 13.0 mass % or less and Fe: 0.02 mass % or more and 0.80 mass % or less;
either disposing two of the first filler-material slab on first and second surfaces of the core-material slab, respectively, or disposing the first filler-material slab on the first surface of the core-material slab and disposing the second filler-material slab on the second surface of the core-material slab, to prepare a clad slab;
performing hot rolling on the clad slab to prepare a clad sheet;
performing a first cold-rolling process on the clad sheet;
annealing the clad sheet after the first cold-rolling process by heating it under conditions in which a total amount of diffusion M calculated according to Equation (1) below becomes 1.0×10 −14 m 2 or more and 5.0×10 −12 m 2 or less; and
performing a second cold-rolling process on the clad sheet after the annealing process;
wherein:
Equation
(
1
)
is
:
M
=
∑
k
=
1
n
D
0
e
-
Q
RT
(
k
)
Δ
t
(
1
)
(n is the number of intervals when the total heating time is divided into units of time Δt,
D 0 is 1.37×10 −5 m 2 /s,
Q is 123 KJ/mol,
R is 8.3145 J/(mol·K), and
T(k) is the heating temperature [K] at the start time of the k th interval.
5. The method according to claim 4 , wherein the casting step includes a cool down step in which an average cooling rate of the core-material slab is 0.13° C./s or more as the core-material slab cools from 550° C. to 200° C.
6. The method according to claim 4 , further comprising:
after the casting step but before preparing the clad slab, subjecting the core-material slab to a homogenization treatment, in which the core-material slab is held at a temperature of 420-510° C. for 0.5-12 hours.
7. The method according to claim 4 , wherein the hot rolling is performed after the clad slab has been pre-heated to a temperature of 420-500° C.
8. The method according to claim 7 , wherein the temperature of the clad sheet at the completion of the hot rolling is 350° C. or lower and the hot rolling is completed within 40 minutes or less.
9. The method according to claim 4 , wherein the first cold-rolling process is performed such that the clad sheet has a thickness of 85.0-99.5% of the thickness of the clad sheet prior to the first cold-rolling process.
10. The method according to claim 5 , further comprising:
after the casting step but before preparing the clad slab, subjecting the core-material slab to a homogenization treatment, in which the core-material slab is held at a temperature of 420-510° C. for 0.5-12 hours.
11. The method according to claim 10 , wherein:
the hot rolling is performed after the clad slab has been pre-heated to a temperature of 420-500° C.,
the temperature of the clad sheet at the completion of the hot rolling is 350° C. or lower and the hot rolling is completed within 40 minutes or less, and
the first cold-rolling process is performed such that the clad sheet has a thickness of 85.0-99.5% of the thickness of the clad sheet prior to the first cold-rolling process.
12. The method according to claim 11 , wherein the aluminum alloy composition of the core material contains:
0.04-0.60 mass % Si;
0.05-0.70 mass % Fe;
1.0-1.8 mass % Mn; and
0.7-2.7 mass % Zn;
the remainder being Al and unavoidable impurities.
13. The aluminum-alloy, fin material according to claim 1 , wherein the aluminum alloy composition of the core material contains 0.04-0.60 mass % Si.
14. The aluminum-alloy, fin material according to claim 1 , wherein the aluminum alloy composition of the core material contains 0.05-0.70 mass % Fe.
15. The aluminum-alloy, fin material according to claim 1 , wherein the aluminum alloy composition of the core material contains 1.0-1.8 mass % Mn.
16. The aluminum-alloy, fin material according to claim 1 , wherein the aluminum alloy composition of the core material contains 0.7-2.7 mass % Zn.
17. The aluminum-alloy, fin material according to claim 1 , wherein the aluminum alloy composition of the core material contains:
0.04-0.60 mass % Si;
0.05-0.70 mass % Fe;
1.0-1.8 mass % Mn; and
0.7-2.7 mass % Zn;
the remainder being Al and unavoidable impurities.
18. The aluminum-alloy, fin material according to claim 1 , wherein the Al—Si series alloy of at least the first filer material contains 6.5-12.0 mass % Si.
19. The aluminum-alloy, fin material according to claim 1 , wherein the Al—Si series alloy of at least the first filler material contains 0.10-0.60 mass % Fe.
20. The aluminum-alloy, fin material according to claim 17 , wherein the Al—Si series alloy of at least the first filler material contains 6.5-12.0 mass % Si and 0.10-0.60 mass % Fe.