JPH0256191B2 - - Google Patents

Description

[Detailed description of the invention]

Field of application: This invention enables the efficient production of lightweight, highly corrosion-resistant, two- or three-layer clad plates of good quality and as heat exchanger components used in particularly harsh environmental conditions, such as heat exchangers. Regarding the manufacturing method. BACKGROUND ART With recent advances in space development, various heat exchangers are also being used in artificial satellites. Generally, Al material is used as a heat exchanger member for the purpose of weight reduction. There has been a demand for materials for heat exchangers that are lightweight and have a long life under harsh atmospheric conditions, but as in the past,
When Al is used for structural members, under harsh environmental conditions, Al is prone to pitting corrosion due to generated moisture, and if pitting corrosion penetrates the Al member, the cooling fluid will leak into other rooms. There is a risk of leakage, which poses a major problem with its reliability. Therefore, as a heat exchanger component, we use an Al-Ti two-layer clad plate, which is a Ti plate coated with an Al plate on one or both sides, which is lightweight, has high corrosion resistance, and has high mechanical strength.
Alternatively, an Al--Ti--Al three-layer clad plate has been proposed, but since it is manufactured by hot pressing, there is a problem in its productivity, and the clad plate cannot be provided at a low price. In order to improve productivity, methods such as cold pressure welding and diffusion annealing, which are common manufacturing methods for clad plates, can be considered. Depending on the diffusion annealing conditions, the growth of intermetallic compounds such as lTi and TiAl ₃ at the welded interface may make the welded interface brittle and reduce its adhesive strength. In addition, depending on the thickness, purpose, and mechanical properties of the product clad plate, it is necessary to perform diffusion annealing, cold rolling, intermediate annealing, finish rolling, etc. If the plate thickness ratio before welding is not appropriate, cracks and tearing will occur in the core Ti plate during cold welding or cold rolling, making it difficult to produce good-quality two- or three-layer clad plates. I couldn't get it. Purpose of the invention This invention solves the problems of conventional Al-Ti clad plates, and eliminates the occurrence of cracks in the Ti core material.
The objective is to provide a method for manufacturing multilayer cladding boards that can be manufactured at high quality and at low cost. Structure and Effects of the Invention This invention sets the thickness of the clad plate on one or both sides of the Ti plate whose surface has been cleaned so that the thickness ratio of the Ti layer and the Al layer is 1:0.01 to 4. Place the aluminum plates facing each other and
After stacking with Ti plate, rolling reduction rate is 30-70% in cold.
In the case of an Al-Ti two-layer clad plate, diffusion annealing is performed in a vacuum at 500℃ to 600℃ for 1 to 6 hours, and in the case of an Al-Ti-Al three-layer clad plate, a vacuum annealing is performed. This is a manufacturing method in which a two-layer or three-layer multilayer clad plate is obtained by diffusion annealing at 500° C. to 600° C. for 1 hour to 6 hours in an inert gas such as N ₂ or Ar gas. By the manufacturing method of the present invention, it is possible to obtain high pressure bonding strength without forming intermetallic compounds at the pressure contact interface between L and Ti, and to efficiently produce a multilayer clad plate having the required mechanical properties. Disclosure of the Invention Based on Drawings The method for manufacturing an Al--Ti--Al three-layer clad plate according to the present invention will be explained with reference to FIG. While unwinding the coiled T plate 1, the surface is mechanically or chemically cleaned, and Al plates 2 and 3 are placed on both sides of the Ti plate 1, which is run rightward in the figure.
are placed on top of each other and cold welded using a pressure roll 4 at a reduction rate of 30% to 70%. At this time, the Al plate 2 has a thickness ratio of 0.01 to 4 with respect to the thickness of the Ti plate. After the above-mentioned cold pressure welding, in a continuous annealing furnace 5, it is heated at 500°C to 600°C for 1 hour in a vacuum or an inert gas.
After diffusion annealing for ~6 hours, if necessary, cold rolling in a rolling mill 6, softening treatment in a softening furnace 7, or intermediate cold rolling, intermediate annealing, finish cold rolling, or further softening treatment, Al-Ti - Obtain an Al three-layer clad plate. Preferred Embodiment of the Invention In this invention, the reason why the thickness ratio of the Al plate and the Ti plate before cold welding is limited to 0.01 to 4:1 is that if the thickness ratio to Ti is less than 0.01, the plate becomes extremely thin. during transport and during cold welding or subsequent cold rolling.
This is not preferable because it causes cracks and cracks in Ti. Furthermore, if the rolling reduction ratio of cold welding is less than 30%, sufficient welding cannot be achieved, and if the rolling reduction ratio exceeds 70%, cracks may occur in the Ti plate, which is not preferable. Diffusion annealing conditions are less than 500℃ and less than 1 hour.
The softening of the plate is insufficient, and if the temperature exceeds 600℃, the growth of intermetallic compounds at the weld interface will be extremely undesirable.If the temperature exceeds 6Hr, the diffusion annealing effect will be saturated and the Al grains will become coarser, which is not desirable. do not have. In addition, the atmosphere during diffusion annealing is oxygen for Ti,
Since it easily absorbs nitrogen and hydrogen gas and greatly changes the properties of Ti, heat treatment in a vacuum is preferable, but it is also possible to coat both sides of the Ti plate with Al plates, or bending or drawing in the subsequent process. When using a flat plate as rolled without processing, diffusion annealing may be performed using an inert gas such as Na gas. The reduction rate of cold rolling after diffusion annealing is selected appropriately depending on the required thickness of the product clad plate, usage conditions, and required mechanical properties, but if the reduction rate exceeds 70%, the Ti plate may crack. , which is undesirable because it causes cracks. Further, the softening treatment conditions after cold rolling may be the same as those for diffusion annealing in terms of atmosphere, temperature, and time. Examples Example 1 An Al plate with a thickness of 2 mm and a width of 300 mm is placed on the plane of a Ti plate with a thickness of 2 mm and a width of 300 mm, which has been rewound by an unwinding roller and whose surface has been buffed, while facing the Ti plate. Run it, overlap both plates, and reduce the reduction rate to 50%.
A two-phase clad plate with a thickness of 2 mm was produced by cold welding. Then, in a vacuum furnace at 250℃, 300℃, 350℃,
Each temperature of 450℃, 500℃, 550℃, 600℃, 650℃,
Diffusion annealing was performed for 1 hour to obtain a test piece with dimensions of 2 mm x 10 mm x 100 mm. As shown in Figure 2, the test piece was bent in the direction of separation at the pressure contact surface to form a roughly T-shape, and its hardness was measured.The pressure contact surface of the test piece was also observed under a microscope. The presence or absence of compound formation was investigated. The results are shown in Table 1.

[Table] Example 2 An Al plate of 0.5 mm in thickness x 300 mm in width was placed on both sides of a Ti plate of 1 mm in thickness x 300 mm in width, which had been rewound by an unwind roller and had its surface buffed, facing the Ti plate. Run it while moving, overlap each plate, and reduce the rolling reduction rate to 60.
A three-layer clad plate with a thickness of 0.8 mm was fabricated by cold pressure welding at 0.8 mm. After that, after diffusion annealing at 550℃ for 3 hours in a vacuum furnace, cold rolling was performed at a reduction rate of 60%.
A three-layer clad board was obtained. A test piece was taken from the clad plate, and the tensile strength, elongation, Young's modulus, volume resistivity, specific gravity, and layer thickness of each layer were measured. The results are shown in Table 2.

【table】

【table】 [Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the manufacturing method according to the present invention. FIG. 2 is an explanatory diagram of the test piece. 1... Ti plate, 2, 3... Al plate, 4... Pressure roller, 5... Continuous annealing furnace, 6... Rolling roller, 7
...Softening treatment furnace.

Claims (1)

[Claims] 1. On one or both sides of a Ti plate whose surface has been cleaned, an Al plate whose thickness is set in advance such that the thickness ratio of the Ti layer and Al layer of the cladding plate is 1:0.01 to 4. After stacking the plates facing each other on the Ti plate, they are cold welded at a reduction rate of 30% to 70%, and then heated in an inert gas or vacuum at 500℃ to 600℃ for 1Hr to 6Hr. A method for manufacturing a multilayer clad plate, characterized by performing diffusion annealing under certain conditions.