JPS62199746A - Tube material for heat exchanger made of aluminum - Google Patents

Abstract

PURPOSE:To obtain an Al-Mn-Cu alloy having superior strength and extrudability as well as superior corrosion resistance as a tube material for a heat exchanger by adding specified amounts of Mn and Cu to Al. CONSTITUTION:An Al alloy contg. 0.5-0.9wt% Mn, 0.05-0.3wt% Cu and impurities including <=0.3wt% Fe and <=0.2wt% Si is used as a tube material for a heat exchanger. The Al alloy tube material has superior strength and extrudability as well as remarkably superior corrosion resistance.

Description

[Detailed Description of the Invention] Industrial Application Field This invention is assembled by brazing extruded pipes and fins, and is used for car cooler evaporators, car cooler condensers, industrial oil coolers, etc. This invention relates to tube materials used for aluminum heat exchanger tubes.

In this specification, "%" indicates "% by weight".

Conventional technology and its problems Conventionally, the aluminum heat exchanger as described above is A11.
A fin made of a brazing sheet made of an A3003 core material and an A4004 skin material was assembled by vacuum brazing to a tube extruded from an aluminum alloy containing 0.00 or 0.5% copper. However, when A1100 is used as the tube material, pitting corrosion occurs in the tube near the joint with the fin, and the tube material has a diameter of 0.5 mm.
When using an aluminum alloy containing 5%, there was a problem that the strength of the tube was insufficient.

An object of the present invention is to provide a tube material for an aluminum heat exchanger that solves the above problems.

Means for Solving the Problems The aluminum heat exchanger tube material according to the present invention contains 0.5-0.9% manganese and 0.05-0.3% copper, with the balance consisting of aluminum and unavoidable impurities. be.

In the above, manganese has the property of increasing the potential of the tube material, increasing the potential difference with the fins when a tube made of this tube material is assembled as a heat exchanger, and increasing the strength of the tube material. However, if the manganese content is less than 0.5%, the above effects cannot be obtained, and if it exceeds 0.9%, extrusion processability during extrusion molding of a pipe will deteriorate. Therefore, the manganese content should be selected within the range of 0.5 to 0.9%, particularly preferably within the range of 0.6 to 0.8%. Copper, like manganese, increases the electric potential of the tube material and increases the potential difference with the fins when a tube made of this tube material is assembled as a heat exchanger.
It has the property of increasing the strength of the pipe material. However, if the copper content is less than 0.05%, the above effects cannot be obtained, and if it exceeds 0.3%, extrusion processability during extrusion molding of a pipe will deteriorate.

Therefore, the copper content 1 should be selected within the range of 0.05 to 0.3%, particularly preferably within the range of 0.1 to 0.2%.

Among the above-mentioned unavoidable impurities, it is preferable that the content of Fe is 0.3% or less and the content of Si is 0.2% or less.

This is because when the contents of Fe and 3i are as described above, the corrosion resistance of the pipe material can be improved. Further, the total content of other unavoidable impurities is preferably 0.05% or less.

Heat exchange with tubes made of the above-mentioned tube materials.

The fin material used for the fins for assembling the vessel has a core material of 0.02 to 0.1% indium and 1 to 1% manganese.
It is preferable to use a brazing sheet made of a known aluminum alloy brazing material of A/-8i series or A/-8i-Ma series, with the remainder being aluminum and unavoidable impurities. . Indium in the core material has the effect of shifting the natural electrode potential of the fin material to the base side and sacrificially corroding the fin against the pipe, and is a substance with extremely low vapor pressure (at 600°C). (approximately 10 −6 iorr), the sacrificial corrosion effect continues even after brazing. Indium content in core material Wtfr0.02-0.1% (7)
If LL is less than 0.02%, the above effects cannot be obtained,
This is because if it exceeds 0.1%, self-corrosion will become too large. The reason why the core material should contain 1 to 1.5% manganese is to increase the strength of the fin material without reducing its workability and corrosion resistance. That is, as the core material, for example, an A3203 alloy to which a predetermined amount of indium is added may be used.

The heat exchange tube made from the above tube material and the fin material made from the above fin material are joined by vacuum brazing, furnace brazing, non-corrosive flux brazing, or the like.

Example Examples of the present invention will be described below along with comparative examples.

Table 1 shows the alloy composition of the tubes used.

Table 1 A billet with a diameter of 6 inches and a length of 400 mm is cast from the above 10 types of pipe materials, and from this billet, a flat tube (1 ) was extruded.

The width of the flat tube (1) is 100ffilIl, the thickness is 51I
The wall thickness of the peripheral wall of the lll11 tube (1) and the wall thickness of the partition wall between adjacent fluid flow passages (2) are 0.7+m. Table 2 shows the extrusion ram speed during extrusion molding of each tube material and the surface condition of the flat tube (1).

(Margin below) Table 2 Next, the extruded flat tube (1) was bent into a meandering shape, corrugated fins were placed between adjacent straight tube sections, and the temperature was 5 x 10 '' Torr, 603°C. A heat exchanger was made by vacuum brazing for 5 minutes. The fin material (IF to 5F) used for the corrugated fins is
Blazing Sea 1~ in which a skin material made of A4004 alloy is clad on both sides of a core material having the alloy composition shown in the table.
Consisting of

(Left below) Table 4 also shows the combinations of tube materials and fin materials in the manufactured heat exchangers. Note that three heat exchangers were prepared for each heat exchanger.

(Left below) Table 4 and 0°5N-N of the tube and fin after vacuum brazing
Table 5 shows the measurement results of the natural electrode potential (based on saturated agaric electrode), the tensile strength of the tube, and the breakdown pressure of the tube in aGz aqueous solution (p l-1 = 7).

(Left below) Also, JISZ237 for each heat exchanger (1 to 14)
A salt spray test based on 1 was conducted to determine the time until leakage occurred from the pipe. The results are shown in Table 6.

(Leaving space below) Table 6 As is clear from Tables 2, 5, and 6, when a heat exchanger is assembled using the tube materials of the example (IT-6T), the tube materials of the comparative example ( The extrudability, strength, and corrosion resistance of the tube are all superior to those obtained when using 7T to 10T).

Effects of the Invention The aluminum heat exchanger tube material according to the present invention contains 0.5 to 0.9% manganese and 0.05 to 0.3% copper, with the balance consisting of aluminum and inevitable impurities. The corrosion resistance of the tubes in the heat exchanger assembled by brazing the tubes with aluminum (including aluminum alloy) fins is excellent. In addition, it has greater strength and extrusion processability than conventional products.

[Brief explanation of drawings]

The drawing is a cross-sectional view of a flat tube extruded from a tube material. 4 people other than the above

Claims (1)

[Claims] Manganese 0.5-0.9% and copper 0.05-0.3
%, with the remainder consisting of aluminum and unavoidable impurities.