JPH0748643A - Aluminum alloy casting material - Google Patents

Abstract

PURPOSE:To provide aluminum alloy casting materials of high wettability of brazer even in a low tem. range. CONSTITUTION:The primary aluminum alloy casting material is one contg., by weight, 4.0 to 13.0% Si and 0.5 to 2.0% Zn, furthermore contg. one or >=two kinds among 0.2 to 0.6% Mg, 1.0 to 4.0% Cu, 0.01 to 0.4% Mn and 0.01 to 0.4% Cr, and the balance Al. Moreover, the secondary aluminum alloy casting material is one in which one or >= two kinds among 0.0005 to 0.01% Be, 0.0005 to 0.05% Sr, 0.0005 to 0.05% Na and 0.01 to 0.3% Ti are added to the same compsn. Furthermore, the concn. of gaseous hydrogen is preferably regulated to <=0.2cc/100g in both aluminum alloy casting materials having the above compsns.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy casting material containing Si and suitable for use as a brazing component material.

[0002]

2. Description of the Related Art Al-Si system, Al-Si-Mg system, A
Aluminum alloy casting materials containing Si, such as 1-Si-Cu, are widely used in various fields because of their excellent castability. Since such an aluminum alloy casting material has a low melting point, when brazing it, an Al—Zn-based brazing material having a low melting temperature is also used as the aluminum alloy casting material.

[0003]

However, when a Zn-Al type brazing material is used for a conventional aluminum alloy casting material containing Si, the wettability at low temperature is poor and good brazing is achieved. Therefore, the brazing temperature must be increased, and there was a danger of melting the base metal.

The present invention aims to solve the above problems by providing a Si-containing aluminum alloy casting material having good brazing properties even at low temperatures and capable of good brazing. To do.

[0005]

A first aluminum alloy casting material according to the present invention is made of Si;
4.0-13.0 wt% and Zn; 0.5-2.0 wt%
In addition, Mg; 0.2-0.6 wt%, Cu;
1.0-4.0 wt%, Mn; 0.01-0.4 wt%, C
r: 0.01 to 0.4 wt% of 1 type or 2 types or more (hereinafter referred to as “Mg group”) is added and added, and the balance is A
It is characterized in that it consists of 1. Moreover, the 2nd aluminum alloy casting material of this invention is Si; 4.0-1.
3.0 wt% and Zn; 0.5-2.0 wt%,
Further, it contains one or more elements of the Mg group, and Be: 0.0005-0.01 wt%, Sr;
0.0005-0.05 wt%, Na; 0.0005-
0.05 wt%, Ti; 0.01 to 0.3 wt% of 1 type or 2 types or more (hereinafter, referred to as "Be group"),
The balance is made of Al.

Furthermore, in any of the above-mentioned aluminum alloy casting materials, the hydrogen gas concentration is 0.2 cc /
It is preferably suppressed to 100 g or less.

In each aluminum alloy casting material composition of the present invention, Si is an essential basic component for obtaining good castability. However, if the Si content is less than 4.0 wt% or 13.0 wt%, the castability decreases, so the Si content needs to be in the range of 4.0 to 13.0 wt%, and particularly 8.0 to 12 wt%. 0.0 wt% is preferable. Zn is Zn-
It is an essential basic component for improving the brazing property when using a low temperature brazing material such as Al. However, if the Zn content is less than 0.5 wt%, no improvement in brazing property is observed,
If it exceeds 2.0 wt%, the corrosion resistance will deteriorate, so the Zn content must be in the range of 0.5 to 2.0 wt%, and 1.0 to 2.0 wt% is particularly preferable.

The elements of the Mg group, namely Mg, Cu,
Mn and Cr are necessary for improving the strength of the aluminum alloy casting material. The strength improving effect can be obtained by mixing one kind of these elements, but two or more kinds may be used in combination. In particular, mainly using Mg and / or Cu,
It is preferable to supplementarily use Mn and / or Cr. These elements have a Mg content of less than 0.2 wt%, C
u content less than 1.0 wt%, Mn content 0.01 wt%
If the Cr content is less than 0.01 wt%, the strength is not improved. Also, when the Mg content is 0.6 wt%, the Cu content is 4.0 wt%, the Mn content is 0.4 wt%, and the Cr content is more than 0.4 wt%, the required mechanical strength is also required. Can't get Therefore, the Mg content is 0.2 to
0.6 wt% range, Cu content 1.0-4.0 wt%, Mn content 0.01-0.4 wt%, Cr
The content must be in the range of 0.01 to 0.4 wt%, and particularly 0.3 to 0.5 wt% and 2.0 to 3.
0 wt%, 0.15-0.3 wt%, 0.15-0.3 wt%
Is preferred.

The elements of the above Be group, namely Be, Sr,
Na and Ti refine the crystal of the Si phase in the Al-Si eutectic structure or the alloy structure as a whole,
It has the effect of improving the strength and toughness of aluminum alloy castings. Such an effect can be obtained by blending one kind of these elements, but two or more kinds may be used in combination. Also,
Be content is less than 0.0005 wt% and Sr content is less than 0.005 wt%.
If the content is less than 0005 wt%, the Na content is less than 0.0005 wt%, and the Ti content is less than 0.01 wt%, the above effect is poor, and the Be content is 0.01 wt% and the Sr content is. 0
5 wt%, Na content 0.05 wt%, Ti content 0.
Even if it is compounded in excess of 3 wt%, the above effect is saturated and it is meaningless to add a large amount. Therefore, the content of Be, Sr, Na and Ti is 0.0005-0.01 wt%, 0.00
It is necessary to set the range of 05-0.05 wt%, 0.0005-0.05 wt% and 0.01-0.3 wt%, and especially 0.001-0.0015 wt%, 0.001-
0.0015wt%, 0.0050.02wt%, 0.02
0.10 wt% is preferable. Further, Be also has an effect of suppressing the oxidation of Mg, and when Mg is contained for the purpose of improving strength as described above, it is preferable to selectively add Be.

In the aluminum alloy casting material having the above-mentioned composition, if hydrogen gas is contained, a pinhole may be formed in the alloy structure, which may reduce strength and toughness or cause blistering during brazing. Therefore, it is preferable to remove hydrogen gas as much as possible, and it is preferable to suppress the hydrogen gas to 0.2 cc or less, particularly 0.1 cc or less, per 100 g of the alloy.

The aluminum alloy casting material of the present invention as described above may be cast by a conventional method, and the hydrogen gas concentration can be controlled by, for example, blowing an inert gas such as argon into the molten metal and agitating the hydrogen gas. It can be done by discharging.

[0012]

The aluminum alloy casting material according to the present invention has excellent castability by containing 4.0 to 13.0 wt% of Si, and also contains 0.5 to 2.0 wt% of Zn. This improves the wettability in a low temperature range with respect to a brazing material having a low melting temperature such as Zn-Al system. As a result, good brazing is possible even at a low brazing temperature, and the base metal is not exposed to unnecessary high temperatures.
In addition, Mg: 0.2-0.6 wt%, Cu: 1.0-
4.0 wt%, Mn; 0.01 to 0.4 wt%, Cr;
The strength of the casting material is improved by the inclusion of one or two or more of 01 to 0.4 wt%.

Further, in the above composition, Be; 0.0005
~ 0.01 wt%, Sr; 0.0005-0.05 wt%,
Na: 0.0005 to 0.05 wt%, Ti: 0.01 to
By adding 0.3 wt% of one type or two or more types, the crystal of the Si phase in the Al-Si eutectic structure or the entire alloy structure is refined, and the strength and toughness of the aluminum alloy casting material are improved.

Further, in the aluminum alloy casting material of each composition as described above, the hydrogen gas concentration is 0.2 cc /
By suppressing the amount to 100 g, it is possible to prevent the strength and toughness from decreasing and prevent blistering during brazing.

[0015]

EXAMPLES Next, specific examples of the aluminum alloy casting material of the present invention will be described.

In accordance with a conventional method, an aluminum alloy casting material having each chemical composition shown in Table 1 below is used to cast a pipe material (1) (2) having an outer diameter of 40 mm and a wall thickness of 2 mm as shown in FIG. did. In addition, No. For 1 to 10 and 12 to 14, in order to suppress the hydrogen gas concentration, Ar gas was blown into the molten metal in the casting step to stir the molten metal to perform degassing treatment.

Next, as shown in FIG. 1, the lap joint is assembled by expanding the diameter of the upper end of one pipe member (2) and fitting the lower end of the other pipe member (1) to the expanded diameter portion.
A ring-shaped brazing material (3) made of a Zn-25% Al alloy was placed on the upper end of the expanded diameter portion, and a flux suspension was applied and dried. Then, this joint is placed in an N ₂ gas atmosphere at 53
It was brazed by heating at 0 ° C. for 5 minutes. Then, after cooling to room temperature, the state of the brazing part was observed and the brazing property was evaluated. The results of these evaluations are also shown in Table 1.

[0018]

[Table 1] As is clear from the results in Table 1, the aluminum alloy casting material No. 1 of the present invention was used. All of Nos. 1 to 11 had good wetting of the wax even at a low temperature of 530 ° C. and could be brazed well. However, in No. 1 which did not control the hydrogen concentration in the aluminum alloy casting material. In No. 11, the wetting of the wax was good, but some blistering occurred due to the heating during brazing. On the contrary,
Comparative Example No. containing no Zn at all. 12, 13 and Z
n with a small n content. No. 14 had poor wax wetting at this temperature and bad brazeability.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing brazing of a lap joint made of an aluminum alloy casting material of the present invention.

[Explanation of symbols]

 1, 2 ... Tube material 3 ... Brazing material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shoichi Sato 6-224 Kaiyamacho, Sakai City Showa Aluminum Co., Ltd.

Claims (3)

[Claims] 1. Si: 4.0-13.0 wt% and Z
n: 0.5 to 2.0 wt% and further Mg: 0.2
.About.0.6 wt%, Cu; 1.0 to 4.0 wt%, Mn;
01-0.4 wt%, Cr; 0.01-0.4 wt%, 1 type or 2 types or more, The balance consists of Al, The aluminum alloy casting material characterized by the above-mentioned. 2. Si: 4.0 to 13.0 wt% and Z
n: 0.5 to 2.0 wt% and further Mg: 0.2
.About.0.6 wt%, Cu; 1.0 to 4.0 wt%, Mn;
01-0.4 wt%, Cr; 0.01-0.4 wt%, one or more, and Be; 0.0005-
0.01 wt%, Sr; 0.0005-0.05 wt%, N
a: 0.0005 to 0.05 wt%, Ti: 0.01 to
It contains 0.3 wt% of one or more kinds, and the balance is Al.
An aluminum alloy casting material comprising: 3. The aluminum alloy casting material according to claim 1, wherein the hydrogen gas concentration in the alloy composition is suppressed to 0.2 cc / 100 g or less.