JPS5985364A - Vacuum brazing sheet for hollow structural body made of aluminum - Google Patents

Abstract

PURPOSE:To provide a titled brazing sheet having improved suitability to brazing and pressure-resistant strength by using an Al-Si-Mg contg. brazing alloy for a facing material on the outside of a hollow structural body made of Al and using an Al-Si brazing alloy for the facing material on the inside thereof. CONSTITUTION:A brazing alloy contg. 5-14wt% Si, 0.2-3% Mg, the balance Al and if necessary, contg. <=1% Bi is used for the skin material on the outside of a hollow structural body in a brazing sheet for the hollow structural body formed by cladding a skin material consisting of an Al contg. brazing alloy on both surfaces of an Al alloy core material. A brazing material contg. 5-14% Si, the balance Al and if necessary, <=1% one or more of Bi, Sn, Sb, Ba, Be is used for the facing material on the inside. The fillet in the joint part of the vacuum brazing sheet is thus made uniform and the strength is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum plating sheet suitable for manufacturing an aluminum heat exchanger having a hollow structure such as a dron cup type oil cooler, evaporator or radiator.

In recent years, a vacuum brazing method that does not require flux has been developed for brazing aluminum structures, and this method has become popular since there is no concern about pollution. Vacuum brazing is a method of brazing in a vacuum using a plating sheet made of an aluminum alloy core and one or both sides of which is clad with an aluminum brazing alloy as a skin material. It is used for attachment.

Various aluminum alloys for core materials and aluminum solder alloys for skin materials have been developed for vacuum plating sheets, and are currently standardized as shown in Tables 1 and 2 according to JIS Z3263.

Table 1 Among these plating sheets, the most commonly used plating sheet uses Shinshi% 3003 alloy and has 10wt plating material on both sides (hereinafter referred to as wt%t-%). Aluminum brazing alloy (BA4004 alloy) containing about 1.5% of Si and about 1.5% of Mg without cladding BA8
PC, which is usually molded into a desired shape and then vacuum brazed in combination.

Conventional Dron cup type oil coolers have a tubular body (1) that is fully laminated as shown in Figure 1.
The fins (2) are placed in between and the stem is manufactured by a brazing method. In addition, as shown in Fig. 2, the radiator has a tank (4) completely attached to the end of a formed flat tube (3).
The fins (2) are arranged between the flat tubes (3) and manufactured by a vacuum brazing method. However, Figures 1 and 2
As shown in the figure, when a structure having a hollow part is manufactured by the full vacuum brazing method, the fillet formation at the inner joint part of the hollow part may not be sufficient and a joint strength of 75r may not be obtained.

In view of this, the present inventors used a currently used vacuum brazing seam (BA8PC) and set the outer diameter as mm as shown in Fig. 3.
, drawn into a cup (5) with a height of 10 mm, and a ventilation hole (6) with a diameter of 3W* in the center of one end surface (5a).
lc, a flange (5b) i was formed on the other end, and this was placed on a one-fin thick substrate (7) made of 3003 alloy so that the flange (5b) was in contact with IU, and vacuum Perform brazing and examine the fillets of the outer joint part (13) and the inner joint part (13) of the base plate (7) and the flange (5b) of the cup (5).As a result, vacuum brazing (vacuum level 3
After 10-' Torr, temperature 1i 600℃, holding time 3 minutes), the inner joint (B storm clearly outer ψ11 polymerization part (
5) In some cases, the fillet is not uniform, and in vacuum brazing of a structure with a hollow part, it has been observed that the bonding state differs between the outside and the inside.

In view of this, the present invention has been made as a result of various studies.
For vacuum brazing of objects such as oil coolers, evaporators, radiators, etc., the outside and inside of the hollow structure must be clad with an aluminum brazing alloy suitable for bonding as a skin material. As a result of further research, we developed vacuum brazing for aluminum hollow structures that forms good fillets at the outer and inner joints and improves brazing properties and pressure resistance. It is something.

That is, the first aspect of the present invention is a plating sheet in which an aluminum hollow structure is uniformly manufactured by vacuum brazing, and a plating sheet is clad with a skin material made of an aluminum brazing alloy on both sides. Si5~14wt% and MgO62~awts in the material
The present invention is characterized in that an aluminum brazing alloy containing 5 to 14 wt % of Si and the remainder At is used for the skin material on the inside of the hollow structure.

The second aspect of the present invention is to manufacture an aluminum hollow structure entirely by vacuum brazing, using an aluminum alloy as the core material, and using an aluminum brazing alloy made of aluminum brazing alloy At on both sides of the core material, and using an aluminum brazing alloy made of an aluminum brazing alloy on both sides. The skin material contains 5 to 14 wt% of Si, 13i, and Sn.

Sb, 13a, 13e, type 1 or 2 fii
The present invention is characterized in that an aluminum brazing alloy is used, which contains at least 1 wt.

The third aspect of the present invention is a plating sheet in which an aluminum hollow structure is manufactured by vacuum brazing.The plating sheet is made of an aluminum alloy as a core material and is clad with a skin material made of an aluminum brazing alloy on both sides, which is the outside of the hollow structure. Si5~14wt% and Mg0.2~3wt in skin material
% and 11 wt% or less of B, and the balance is At, and the skin material forming the inside of the hollow structure contains 5 to 14 wt% of 3i, and the balance is ht. It is something.

Fourthly, the third aspect of the present invention is to manufacture an aluminum hollow structure by vacuum brazing.In a plating sheet in which an aluminum alloy is used as a core material and both sides are clad with a 1" thick skin made of an aluminum brazing alloy, the outer side of the hollow structure is Si5~14wt% and MgO13~3wt% in the skin.
and Bi1wtqb or less, and the balance is At, the hollow structure's B a, B e
The present invention is characterized by using an aluminum brazing alloy containing any one of the following or 28a or more and fl wt% or less, and the balance being At.

As described above, the plating sheet of the present invention has an aluminum solder alloy clad as a skin material on both sides of a core material made of an aluminum alloy. The skin material containing 5 to 14 wt% of Si and 12 to 3% of MgO, the balance being At or 5 to 14% of Si, 0.2 to 31% of Mg,
An aluminum alloy containing 1% or less of Bi and the remainder At is used, and the skin material inside the hollow structure is made of Si5-14
13i, with the remainder At or Si 5-14%.

It uses an aluminum brazing alloy containing one or more of Sn, Sb, Ba, and 13e in a total of 1 qb or less, and the balance is At, and the core material is not particularly limited, but it is 3003 as before. Starting with alloys, 30
05 alloy (At-1, 0-1.5% Mn-0, 20-0
．． 6% Mg), 6951 alloy (AL-0,2~0.5
%5i-0,15~0.4%Cu-0,4~0.8%M
g) etc. may be used.

The addition of Si as a skin material lowers the melting point of the skin material to the melting point of the core material, especially the addition of Mg to the outer skin material, which is evaporated during vacuum brazing and reacts with H, 0, and 0 in the atmosphere. By doing so, 02 in the atmosphere is collected, A L * Os covering the surface of the skin material is destroyed due to the difference in thermal expansion with At, and AA exposed to the surface is prevented from being reoxidized. This is to improve the wettability of the wax cake, and Bi is added if necessary to further improve the wettability of the wax chestnut. On the other hand, the reason why we used a brazing alloy that does not contain MgY for the skin material on the circular side is that if Mg is present in the inner skin material, the Mg evaporated during vacuum brazing will be absorbed into the hollow part.
This is because Mg0i is generated by reacting with B IXS ns S b % B because it is difficult to come out and adheres to the surface of the brazing material again and obstructs the flow of the brazing material.
a) One flft or two or more of the examples of B and e may be added if necessary to further improve the wettability of the brazing filler metal.

The reason why the brazing alloy compositions of the outer skin material and the inner skin material of the hollow structure are limited as described above is as follows.

Si of the outer skin material and the inner skin material of the hollow structure
If the content is less than 5%, the fluidity as a brazing material will be low;
If it exceeds 4%, the molding process becomes difficult, so it is particularly desirable to keep the Si content within the range of 7 to 12 cracks. Furthermore, if the Mg content of the outer skin material is less than 0.2%, it will not be possible to sufficiently collect oxygen in the atmosphere, including the inside of the hollow structure, making brazing difficult. If it exceeds Mg, not only the effect of Mg will be saturated, but also the moldability will be deteriorated.
7. Furthermore, Mgft adhering to the inside of the vacuum furnace increases, causing problems in furnace maintenance, especially when the Mg content f:
It is desirable to set it within the range of 0.5 to 2%. In addition, the 13i content is 1% to improve the wettability of the outer brazing filler metal.
This is because, if it exceeds this value, not only the effect of Bi will be saturated, but also the moldability and plastic workability will decrease. Further inside 11111
Bi% Sn% S to improve the wettability of the brazing filler metal
b% If the content of one or more of Ba and Be exceeds 1%, the effect of this element will be saturated or the moldability and plastic workability will deteriorate.

All embodiments of the present invention will be described below.

A vacuum plating sheet with a thickness of 1 mm is used, with a core material of 30030-alloy and both sides clad with a skin material made of a brazing alloy having the composition shown in Table 3. A cup (5) with a height of 10+nm is drawn and processed,
A ventilation hole (6) with a diameter of 3rMn was formed at the center of one end surface (5a), and a tsuba (5b) was formed at the other end.
As shown in the figure, the flange (5b) is placed on a one-thickness substrate (7) made of 3003 alloy so that it is in contact with the flange (5b), and the end face (5a) and the flange (5b) are placed on it. ] Lay them together so that they are in contact with each other, and vacuum level is 3 x 10-' Torr.

Vacuum brazing was performed at a heating temperature of 600° C. and a holding time of 3 minutes.

With respect to the products subjected to vacuum brazing in this manner, the state of the fillet at the inner joint portion was examined and a one-surface pressure test was conducted. The results are also listed in Table 3.

As is clear from Table 3, Sl and M
It can be seen that when vacuum bracing is performed using the sheeter of the present invention, which contains all G and does not contain Mg in the inner skin material, the condition of the fillet inside the hollow structure can be made uniform and the compressive strength can be significantly improved. Also, the outer skin material is made of Si.

13i is impregnated with Mg in a range of 1 or less, and V and inner skin material are impregnated with Si together with B i%S ns S bs
A total of 1% of one or more of B a or B e.
When vacuum brazing was performed using the sheet la of the present invention containing the following content, a slight improvement in compressive strength was observed.

On the other hand, it can be seen that problems occur when an outer skin material or an inner skin material is used outside the composition range defined by the present invention. That is, in the outer skin, comparative skin material No. 19 with a high Si content and comparative skin material N [L21 with a high Mg content]
The workability of the comparative skin material No. 23, which has a high Si content, deteriorated and it was not possible to draw it into a cup shape. In addition, comparative skin materials NIIL20 and M with low Si content
Comparative skin 1'N [122 tl'' with less g-containing material was used, and the fluidity of the solder was poor, and the formation of the outer fillet after brazing was uneven, resulting in a decrease in pressure resistance.In addition, the inner skin material Comparative skin materials with a high content of 3i Na24 and Bis Sns Sb% Bas Be, or a comparative skin material with a high total content of one or more types 26, tt
All of the products using No. 27e have poor workability and cannot be drawn into a cup shape. In addition, when using the comparative skin material Nα25 with a low 3i content, the fluidity of the solder was poor, and the formation of the inner fillet after brazing was uneven.
Compressive strength has decreased.

As described above, the plating sheet of the present invention can significantly improve the uniformity and strength of the fillets at the joints in vacuum bracing of hollow structures, such as oil coolers with hollow structures, voluminators, radiators, etc. It has remarkable effects such as being able to completely improve the pressure resistance of the heat exchanger.

[Brief explanation of the drawing]

Figure 1 is a t111 side view of an oil cooler manufactured by vacuum brazing, Figure 2 is a side cross-sectional view of a radiator manufactured by vacuum brazing, and Figure 3 is an example of an A empty brazing test cup, partially cut away. FIG. 4 is a perspective view showing an example of a pressure-resistant test structure in which a test cup is joined by vacuum bracing. 1......Tubular body 2...Fin 3...Flat tube 4... ......Tank 5...Cup-shaped test piece 6...
・・・・・・・・・Vent hole 7・・・・・・・・・・・・Board

Claims (4)

[Claims] (1) Manufacturing a hollow structure made of aluminum by vacuum brazing In a plating sheet made of an aluminum alloy as a core material and clad with a skin material made of an aluminum brazing alloy on both sides, the skin material on the outside of the hollow structure is Si
5 to 14 wt% and Mg0.2 to 3 wt%, the balance A
Using an aluminum brazing alloy consisting of 4, the skin material forming the inside of the hollow structure contains 5 to 14 wt% of Si, and the balance is At.
A vacuum plating sheet for aluminum hollow structures, characterized by using an aluminum brazing alloy consisting of: (2) Manufacturing an aluminum hollow structure by vacuum brazing In a brazing sheet with an aluminum alloy as a core material and a skin material made of an aluminum brazing alloy on the face, the skin material on the outside of the hollow structure is made of Si.
The remainder is AL, including 5-14wt and Mg0.2-3wt.
Using an aluminum brazing alloy consisting of 5 to 14 wt% of 3i and B l, S n to the skin material that becomes the inside of the hollow structure.
, Sb-, Ba, Be, or more, in a total of 1 wt % or less, and the balance is At. Made of aluminum hollow structure. Empty praising sheet. (3) Manufacturing an aluminum hollow structure by vacuum brazing In a plating sheet with an aluminum alloy as a core material and a skin material made of an aluminum brazing alloy on both sides, the skin material on the outside of the hollow structure is made of Si.
5 to 14 wt% and Mg0.2 to 3 wt% and 1311
Using an aluminum brazing alloy containing 5 to 1 wt% and the remainder At, the skin material that becomes the inside of the hollow structure contains Si5 to 1
A vacuum plating sheet for an aluminum hollow structure, characterized in that it uses an aluminum brazing alloy containing 4 wt% of the total content and the remainder of At. (4) Manufacturing an aluminum hollow structure by vacuum brazing In a plating sheet that uses an aluminum alloy as a core material and clads both sides with a skin material made of an aluminum brazing alloy, the skin material on the outside of the hollow structure is made of Si.
5-14wt%, Mg0.3-3wtchi and B11wt%
Using an aluminum brazing alloy containing the following, with the remainder being At, the skin material that will be inside the hollow structure is S i 5 J
w t %, and BI Sn% Sb% Ba. A vacuum plating sheet for an aluminum hollow structure, characterized by using an aluminum brazing alloy containing one or more f: 1wt% or less of 13e and the remainder being AL.