JPS6351791B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a plate-shaped Ti-Al-Ti clad material, and in particular, it can produce excellent bonding strength, flatness, and other properties with relatively simple operations. Plate-shaped Ti with characteristics
-Relates to a method for producing Al-Ti clad material.

[Prior Art] Ti--Al clad material is a composite metal material that combines the excellent corrosion resistance of Ti and the excellent electrical conductivity of Al, and can be used in a wide range of applications, including electrodes for electrolysis. However, Ti and Al have a large difference in melting temperature, tend to form brittle intermetallic compounds at the bonding interface, and have a large difference in coefficient of thermal expansion.
It has various problems such as easy formation of a strong oxide film. That is, Ti-Al is TiAl ₃ within a certain composition range.
This produces brittle intermetallic compounds such as TiAl and TiAl, which significantly reduce the strength and toughness of the joint. Furthermore, when joined at high temperatures, cracking or peeling may occur due to differences in cooling shrinkage due to differences in thermal expansion coefficients. Furthermore, similar problems may occur when exposed to high temperatures during welding or the like after manufacture, and the high temperatures may also promote the growth of intermetallic compounds, which may adversely affect the joints. Furthermore, these metals form a protective oxide film in the atmosphere and exhibit corrosion resistance, but when manufacturing cladding materials,
Unless this oxide film is removed in advance, good metal-to-metal bonding cannot be achieved. Therefore, it is necessary to remove the oxide film and clean it in advance.

For these reasons, in the past, for example,
As disclosed in Japanese Patent No. 20747, a method is adopted in which the oxide film on the metal surface is removed, the metals are overlapped, and the metals are hot-pressed or hot-rolled.

[Problems to be solved by the invention] However, these methods require selective reduction of Al, and it is difficult to apply lubricating oil and set conditions such as roll diameter and roll speed, and even if suitable conditions are set, the cladding material It is easy to cause bending, etc., and it is necessary to correct the flatness by cold rolling or the like. Moreover, there is also the problem that bonding properties vary due to variations in rolling reduction. There is also a method of applying aluminized treatment, plating treatment, etc. and rolling it as an insert material, but these also involve a large number of steps and are not suitable for actual circumstances.

The present inventors have been conducting various improvement studies on the manufacturing method of Ti-Al-Ti clad materials, especially Ti-Al-Ti clad materials, for some time.
As a result, even if a method of bonding using a brazing sheet using Al brazing material is adopted, excellent bonding strength can be obtained under appropriate conditions that suppress the excessive growth of intermetallic compounds at the bonding interface. Embrittlement due to oxidation and nitridation of Ti is suppressed by joining in a vacuum, and the cladding material brazed using Al brazing sheet has excellent flatness compared to the rolled cladding material mentioned above. The present invention was completed based on these findings.

[Means for Solving the Problems] The method for manufacturing the plate-shaped Ti-Al-Ti clad material according to the present invention is as follows: Al or A Ti plate or a Ti alloy plate (hereinafter simply referred to as a Ti plate) is stacked on top of a brazing sheet formed by forming an Al or Al alloy brazing material layer on both surfaces of an Al alloy sheet, and then brazed under vacuum. The key point lies in the fact that it has become possible to provide an extremely high quality plate-shaped Ti--Al--Ti clad material that is free from bending using a relatively simple method.

[Function] In the present invention, the surfaces of the Ti plate 1 and the Al plate 2 are cleaned by subjecting them to treatments such as pickling, brushing, and degreasing, and for example, as shown in FIG. A brazing sheet 4 with a brazing filler metal 3 for Al layered on both sides is interposed, and a brazing sheet 4 is placed on both sides of the Al plate 2.
The Ti plates 1 are stacked and transported into a brazing furnace.

The brazing conditions are the same as for normal Al vacuum brazing, and since the atmosphere is vacuum, the Al plate and
Brittleness due to oxidation and nitridation of the surface of the Ti plate is prevented. Also, during brazing, heavy objects are placed on top of the stacked items to improve the adhesion of the joint surfaces.
By using a method in which multiple sets of objects to be brazed are laminated and soldered simultaneously, the adhesion can be improved by the weight of the objects to be brazed, and furthermore, the brazing time per unit of brazing object can be shortened. It's advantageous.

Further, when obtaining a complete coating with Ti, for example, by combining a Ti plate 1, an Al plate 2, and a brazing sheet 4 as shown in FIG. 2, soldering can be performed in one cycle.

The clad material obtained in this way has excellent bonding strength and flatness, as shown in the examples below, and is free from embrittlement due to oxidation and nitridation of Ti, and has a good appearance and It is of extremely high quality in terms of performance etc. The clad material obtained by the present invention can be put to practical use as it is, but it is also possible to perform further processing such as rolling.

The Ti alloy to be joined in the present invention includes Ti
-5Ta, Ti-6Al-4V, Ti-5Al-2Cr-
Fe, Ti―5Al―2.5Sn, Ti―15Mo―5Zr, Ti―
Examples include 15Mo-5Zr-3Al, and Al alloys include Al-Mn, Al-Mg, Al-Mg-Mn, Al
-Mg-Si, Al-Mg-Si-Cu, Al-Si-Mg,
Examples include Al--Zn--Mg, and the type thereof can be appropriately selected depending on the physical, chemical, electrical, etc. properties of the intended cladding material. In addition, all brazing sheets used for brazing Al or Al alloys can be used as brazing sheets for brazing, and the best ones include Al-Si or Al-Si-Mg brazing sheets. Formed on both sides of an Al or Al alloy sheet.

[Examples] Next, Examples are shown below, but they do not limit the present invention, and can be implemented with appropriate changes in accordance with the spirit of the above and below. included in the range.

Example 1 Two pure Ti plates cleaned with nitric-fluoric acid [0.5 ^t × 100 ^w ×
100 ^l (mm)] of pure water washed with caustic soda and nitric acid.
Both sides of the Al plate were laminated with the following brazing sheets interposed therebetween, and vacuum brazing was performed under the following conditions.

[Brazing sheet] Core material: Pure Al Brazing material: Al-9.5Si-1.5Mg or Al-7.5Si Dimensions: 0.6 ^t × 100 ^w × 70 ^l (mm) Cleaning: Sequential cleaning with caustic soda and nitric acid [Brazing Conditions] Layering method: Layering as shown in Figure 3, 20g/
cm ² or 50 g/cm ² weight 5 is placed. Vacuum level: 10 ^-4 mmHg Temperature: 605℃ x 5 minutes for Al-9.5Si-1.5Mg.
In the case of Al-7.5Si, 615°C x 5 minutes The appearance and microscopic observation results of the obtained clad plate are shown below.

[Appearance properties] In the obtained clad plate, the coefficient of thermal expansion of Ti and Al is different (the coefficient of thermal expansion of Al is more than twice that of Ti).
However, since Ti is clad on both sides of Al,
No bending or warping due to thermal expansion differences occurs,
A clad material with extremely high flatness was obtained. In addition, a good bonding condition was obtained regardless of the type of brazing filler metal.

[Microscopic observation results] Figure 10 shows Al-9.5Si-1.5Mg as a brazing material.
Using a brazing sheet with a load of 50
An enlarged photograph (200x) showing the metallographic structure of the cross section of the joint of the clad plate obtained by brazing at g/ ^cm2 . Enlarged photograph (400x) in place of the drawing shown,
FIG. 4 shows the results of line analysis of the joint boundary of the same clad plate. Figure 12 is ^an enlarged photograph (200x ), Figure 13 is an enlarged photograph (400x) showing the metal structure of the cross-section of the boundary between Ti and brazing metal of the same clad plate, and Figure 5 shows the line analysis results of the joint boundary of the same clad plate. It is something.

As is clear from FIGS. 10 to 13, no large voids were observed near the joints, and a good joint state was obtained. Furthermore, as is clear from Figures 4 and 5, intermetallic compounds are generated at the bonding boundary, and the thickness of the diffusion layer is approximately 10.0 μm when Al-9.5Si-1.5Mg is used, and the thickness of the diffusion layer is approximately 10.0 μm when Al-9.5Si-1.5Mg is used. When 7.5Si was used, it was approximately 8.0 μm.

Example 2 Pure Ti plate cleaned with nitric-fluoric acid [0.5 ^t × 600 ^w × 1110 ^l
(mm)], brazing sheet cleaned with caustic soda and nitric acid [0.65 ^t × 600 ^w × 1150 ^l (mm)] and pure Al plate cleaned with caustic soda and nitric acid [4.0 ^t × 600 ^w ×
1230 ^l (mm)] were further wire brushed and degreased with acetone, and then stacked as shown in Figure 6. These five sets were stacked and a weight equivalent to 190 to 200 g/cm ² was placed on top. Vacuum brazing was performed. An Al plate was placed at the bottom of the stack to improve heat conduction and ensure flatness. The brazing conditions were a vacuum level of 10 ^-4 mmHg, a temperature of 615°C, and a time of 15 minutes.

The appearance properties, microscopic observation results, and quality test results of the joint boundary area of the obtained clad plate are shown below.

[Appearance Properties] The obtained clad plate had excellent flatness and the bonded state was also extremely good. Moreover, when we measured the thickness error of five clad plates, all of them were within ±0.10mm.

[Microscopic observation results] Figure 14 (500x), Figure 15 (200x), and Figure 16 (400x) are enlarged photographs showing the metal structure of the cross section of the brazed part, and the lines of the joint boundary. The analysis results are shown in Figure 7. As a result, it can be confirmed that the bonding state is good, but the 14th to 16th
The figure shows the formation of tongue-shaped intermetallic compounds. Further, from FIG. 7, the thickness of the diffusion layer is approximately 13.0 μm, which is slightly thicker than that in Example 1 (10.0 μm). This is considered to be because the brazing time was 10 minutes longer than in Example 1.

[Quality of boundary area] A. Adhesive strength When the resulting clad plate was cut as shown in Figure 8 and the tensile shear adhesive strength was measured at a portion of length L, the results shown in Figure 9 were obtained. . From this result, the shorter L is, the higher the adhesive strength is, and when L is 1 mm, it shows a value of 12.0 Kg/mm ² .

B Bending test The obtained clad plate was bent to a radius of 0.4t ^R , 1.0t ^R and
A 180 degree U-bend was performed at 2.0t ^R , and the state of peeling and cracking at the joint was observed. As a result, both peeling and cracking occurred at 0.4t ^R , but at 1.0t ^R and
No abnormality was observed with 2.0t ^R. According to the Ti standard, the bending limit radius is ^1.5tR for the base material and ^2.0tR for the welded part, and the clad plate obtained by the present invention fully satisfies the standard.

[Effects of the Invention] The present invention is structured as outlined above, and its effects are summarized as follows.

This method uses a brazing sheet for Al brazing, and a reliable bond can be obtained regardless of the type of Ti or Ti alloy and Al or Al alloy, and the material can be selected according to the application.

Since a vacuum brazing method is used, embrittlement due to Ti oxidation and nitridation does not occur.

The degree of freedom in determining the thickness of the bonding material is wider than in the rolling method, and it is possible to obtain cladding materials with dimensions that suit the application.

Although the thermal expansion coefficients of Al and Ti are quite different, the clad material obtained by the present invention has Ti, which has a small thermal expansion coefficient, bonded to both sides of Al, so that even when subjected to temperature changes, the amount of expansion and contraction on both sides is small. Since they are the same, the clad plate itself will not bend or warp, and a clad plate with high flatness can be obtained. Furthermore, Al and Ti are bonded via a brazing sheet layer, and internal strain occurring at the bonded portion due to the difference in thermal expansion is absorbed and relaxed by the brazing layer, thus ensuring a stable bonded state.

If the method shown in FIG. 2 is adopted, it is possible to manufacture a completely covered clad material at the same time as brazing, increasing productivity.

[Brief explanation of the drawing]

Figures 1 and 2 are conceptual diagrams illustrating the superimposition method of Ti and Al, Figures 3, 6, and 8 are explanatory diagrams to support the examples, and Figures 4, 5, and 7 are obtained by the present invention. A line analysis chart of the joint boundary of the cladding material, FIG. 9 is a graph showing the measurement results of adhesive force, and FIGS. 10 to 16 are enlarged photographs in place of drawings showing the metal structure of the cross section of the brazed part. 1...Ti or Ti alloy, 2...Al or Al alloy, 3...
Al brazing filler metal, 4...brazing sheet, 5...money.

Claims (1)

[Claims] 1 Ti plate or Ti alloy plate through a brazing sheet formed by forming a brazing material layer for Al or Al alloy on both surfaces of the Al plate or Al alloy plate. A plate-shaped Ti plate characterized by overlapping and vacuum brazing
Manufacturing method of Al-Ti clad material.