Aluminum-alloy brazing sheet and manufacturing method thereof

Patent metadata

Field	Value
Publication number	US-11772205-B2
Application number	US-202017794809-A
Country	US
Kind code	B2
Filing date	Mar 30, 2020
Priority date	Mar 30, 2020
Publication date	Oct 3, 2023
Grant date	Oct 3, 2023

Abstract

A brazing sheet ( 1 ) includes a core material ( 11 ) composed of an Al alloy containing 0.40-2.50 mass % Mg; and a filler material ( 12 ) composed of an Al alloy containing Mg, 6.0-13.0 mass % Si, and 0.010-0.050 mass % Bi. The filler material is layered on a side of the core material and is exposed at an outermost surface ( 121 ). The Mg concentration in the filler material continuously decreases in a direction from a boundary ( 122 ) with the core material toward the outermost surface. The Mg concentration (c 1/8 ) is 0.080 mass % or less at a depth (position P 1/8 ) from the outermost surface that is ⅛ of the thickness t f of the filler material ( 12 ). The Mg concentration (c 7/8 ) is 15-45% of the amount of Mg in the core material at a depth (position P 7/8 ) from the outermost surface that is ⅞ of the thickness t f of the filler material.

First claim

The invention claimed is:

1. An aluminum-alloy brazing sheet for use in brazing performed without flux, comprising:
a core material composed of an aluminum alloy that contains 0.40 mass % or more and 2.50 mass % or less of Mg; and
a filler material composed of an aluminum alloy that contains Mg, 6.0 mass % or more and 13.0 mass % or less of Si, and 0.010 mass % or more and 0.050 mass % or less of Bi, the filler material being layered on at least one side of the core material and is exposed at an outermost surface of the brazing sheet;
wherein:
the filler material:
has an Mg distribution such that the Mg concentration becomes continuously lower in a direction from a surface of a boundary with the core material toward the outermost surface;
at a position at which the depth from the outermost surface is ⅛ of the thickness of the filler material, the Mg concentration is 0.080 mass % or less; and
at a position at which the depth from the outermost surface is ⅞ of the thickness of the filler material, the Mg concentration is 15-45% of the amount of Mg in the core material.

2. The aluminum-alloy brazing sheet according to claim 1 , wherein the filler material further contains one or two elements selected from the group consisting of Sr: 0.10 mass % or less and Sb: 0.10 mass % or less.

3. The aluminum-alloy brazing sheet according to claim 1 , wherein the core material further contains one or two or more elements selected from the group consisting of Fe: 1.0 mass % or less, Mn: 1.80 mass % or less, Si: 1.0 mass % or less, Cu: 1.0 mass % or less, Zn: 3.0 mass % or less, Ti: 0.20 mass % or less, and Zr: 0.50 mass % or less.

4. The aluminum-alloy brazing sheet claim 1 , wherein the filler material is layered on both surfaces of the core material.

5. The aluminum-alloy brazing sheet according to claim 1 , wherein the brazing sheet comprises: the core material; the filler material layered on a first surface of the core material; and a sacrificial-anode material composed of pure aluminum or an aluminum alloy that contains Zn: 8.0 mass % or less, the sacrificial-anode material being layered on a second surface of the core material.

6. The aluminum-alloy brazing sheet according to claim 5 , wherein the sacrificial-anode material is composed of an aluminum alloy that further contains one or two or more elements selected from the group consisting of Mn: 2.0 mass % or less, Mg: 3.0 mass % or less, Si: 1.5 mass % or less, Fe: 1.0 mass % or less, Cu: 1.0 mass % or less, Ti: 0.3 mass % or less, Zr: 0.3 mass % or less, and Cr: 0.3 mass % or less.

7. The aluminum-alloy brazing sheet according to claim 5 , wherein the sacrificial-anode material is composed of an aluminum alloy that further contains one or two elements selected from the group consisting of In: 0.0050-0.100 mass % and Sn: 0.0050-0.100 mass %.

8. An aluminum-alloy brazing-sheet manufacturing method according to claim 1 , comprising:
preparing a clad slab comprising: a core-material slab, which has the chemical composition of the core material; and a filler-material slab, which is composed of an aluminum alloy that contains 6.0 mass % or more and 13.0 mass % or less of Si and 0.010 mass % or more and 0.050 mass % or less of Bi, the filler-material slab being overlayed on the core-material slab;
preparing a clad material by hot rolling the clad slab to join layers constituting the clad slab; and
forming the Mg distribution in the filler material by performing one or more passes of cold rolling on the clad material and diffusing Mg by heating the clad material one or more times between passes of the cold rollings and/or after a last pass of the cold rolling.

9. The aluminum-alloy brazing-sheet manufacturing method according to claim 8 , comprising:
when Mg is to be diffused from the core material into the filler material, heating the clad material under a condition in which a value of D in Equation (1) below is 1.0×10 −15 -3.0×10 −9

D
=

∑

k
=
1

n

10

-
8

⁢

Th
k

-
2

⁢

∫

t

k
⁢
0

t

k
⁢
1

1.24
×

10

-
4

⁢

e

-

130000

RT
(
t
)

⁢
dt

(
1
)

Assignees

• Uacj Corp

Inventors

• Nakamura Shinichi
• YAMAYOSHI Tomoki
• DOKOU Takeyoshi

Classifications

• B23K35/286 Primary

  Al as the principal constituent · CPC title

• B23K35/0238

  layered · CPC title

• C21D8/0226

  Hot rolling · CPC title

• C22C21/02

  with silicon as the next major constituent · CPC title

• C22C21/06

  with magnesium as the next major constituent · CPC title