JPH0525563B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for manufacturing a cold-rolled titanium alloy ultrathin plate. Titanium alloys are lightweight and have excellent corrosion resistance and strength, so they are used in a wide range of fields such as the aerospace industry and the marine industry. The present invention relates to a method for manufacturing this cold-rolled ultra-thin plate of titanium alloy. [Prior art] In this specification, titanium alloy means Ti+6Al− when cooled.
α of 2Sn−4Mo−2Zr alloy, Ti−6Al−4V alloy, etc.
−β titanium alloy. Titanium alloy has excellent corrosion resistance and strength, but is a difficult-to-work material with poor plastic workability. Therefore, it is difficult to produce plates with a thickness of 6 mm or less using normal hot rolling. Even thinner titanium alloy plates are produced by stacking several hot-rolled plates to form a special slab and then hot-rolling the slab, which is called pack rolling, but even with this method, the thickness is 0.4 It is difficult to roll a thin plate with a diameter of less than mm, and titanium thin plates rolled by this method have large variations in plate thickness and poor surface smoothness. Ultra-thin titanium alloy plates are usually produced by grinding or melting the surface of hot-rolled plates, but grinding or melting the surface to a uniform thickness is technically unstable. Yes, and it is not efficient. JP-A-63-177905 relates to a method for cold rolling α+β titanium alloy plates. This publication describes a method in which a cut plate of a titanium alloy, for example, having a thickness of 5 mm to 10 mm, is cold rolled by a normal cold rolling method at a total reduction of 30% or less, and then annealed. However, in cold rolling of cut plates, there is no winder, so it is difficult to produce thin, ultra-thin plates with good shape, and there is a limit to the thickness that can be obtained. In addition, when cold rolling materials with a thickness of 5 to 10 mm with a total reduction rate of 30%, the number of intermediate annealing increases.
Manufacturing extremely thin titanium alloy plates is extremely complicated. [Problems to be Solved by the Invention] The present invention involves cold rolling an ultra-thin titanium alloy plate.
The present invention provides a method for producing an ultrathin plate with high efficiency and excellent shape. [Means and effects for solving the problem] First, the invention of claim 1 will be explained. If a titanium alloy plate can be rolled with small-diameter rolls while applying tension to the plate using, for example, a Sendzimir cold rolling mill, it is possible to increase the rolling reduction per pass and efficiently cold-roll the plate. One possible way to apply tension to the plate is to wrap the titanium alloy plate around tension rolls on the front and rear sides of the cold rolling mill. However, the titanium alloy plate subjected to this cold rolling is, for example, Ti-6Al-2Sn-
Since the 4Mo-2Zr alloy has a tensile strength of about 110 Kgf/mm ² and is high in strength, it is difficult to wind it onto a tension reel. It is conceivable to join a carbon steel or stainless steel leader coil to the front and rear parts of a titanium alloy plate and wind it around a tension reel via the leader coil, but if the titanium alloy plate and carbon steel or titanium When alloy plates and stainless steel are welded, fragile intermetallic compounds are generated in the welded area, making the weld extremely brittle, and in a general sense, welding is impossible, so the titanium alloy plate is rolled under tension. I can't. In addition, mechanical joining such as rivets is satisfactory in terms of joining properties, but since holes are drilled into thin plates and joined with rivets, when the joint comes into contact with the take-up roll, the drilled holes of the rivets may be damaged. This is not a satisfactory joining method because the rivets become large, the rivets come off, and the rivets are cut from the drilled hole. The present inventors welded pure titanium leader coils to the front and rear parts of a titanium alloy plate, and wound the leader coils around tension reels provided at the front and rear sides of a cold rolling mill, respectively. Tension was applied to the titanium alloy plate through a coil for rolling, and since pure titanium has a tensile strength of about 45 Kgf/mm ² and is soft, it was easy to wind it around a tension reel. Furthermore, the welded joint between the titanium alloy and the pure titanium leader coil was able to ensure sufficient ductility, making it possible to cold-roll the titanium alloy plate with the desired tension applied. When welding a titanium alloy and a pure titanium leader coil by, for example, TIG welding, resistance welding, or MIG welding, a stable joint can be obtained. The present inventors used a titanium alloy plate with a thickness of 0.4 to 3 mm and cold-rolled it using this method.
The reduction rate per pass was also large, and cold rolling with a total cold rolling rate of 40% or less was achieved. Figure 1 shows a Ti-6Al-4V alloy plate (thickness: 0.4mm)
FIG. 3 is a diagram showing the relationship between the rolling tension and the total cold rolling rate on the occurrence of edge cracks when cold rolling is performed with tension applied to the steel sheet. The titanium alloy material cold-rolled at a total rolling reduction of 40% or less was heat treated and refined to form a cold-rolled coil. Conventionally, cold-rolled titanium alloy coils thinner than 0.4 mm have not been manufactured, but they can be efficiently manufactured using the method of the present invention. When manufacturing thinner cold-rolled sheets or foils, the following steps are required:
The processing according to claim 2 is performed. As already mentioned, titanium alloy has poor plastic workability and tends to cause edge cracks during cold rolling. After that, a treatment is performed to restore cold rolling properties. As a treatment for restoring the cold rollability of the titanium alloy, the cold rolled material is intermediately annealed (heat treated) at 600°C to 950°C. This heat treatment recrystallizes the metal structure and removes the processing strain caused by cold rolling.
It is said that the cold rollability of the cold-rolled coil is restored. However, according to the findings of the present inventors, although the rolling structure and mechanical properties of cold-rolled coils are improved by this heat treatment, the cold workability of the edge portions cannot be recovered by this heat treatment alone. However, it is easy to cause edge cracks in the next cold rolling. The present inventors performed side trimming during this heat treatment, but this side trimming removes the edges of the cold rolled coil where edge cracks are likely to occur, thereby preventing the occurrence of edge cracks in the next cold rolling. I can do that. FIG. 2 is a diagram illustrating an example of this effect, showing the effect of trimming on the occurrence of edge cracks. In Fig. 2, the rolling tension is 10 to 15 kg/mm ² and the plate thickness is 0.47 mm → 0.08 mmt. The present inventors have discovered that Ti-
6Al−2Sn−4Mo−2Zr alloy plate (width: 380mm),
Cold rolled by the method of claim 1 so that the total cold rolling ratio becomes 40%, and a cold rolled coil with and without side trimming on both sides of the cold rolled coil by 3 mm before heat treatment is produced. did. All of these cold-rolled coils were heat-treated, and then, in the same manner as described in claim 1, the titanium alloy coil was passed through and cold-rolled while applying tension. As shown in Figure 2, side cracks are likely to occur in coils without side trimming when the total cold rolling rate exceeds approximately 20%, but in coils with side trimming, side cracks tend to occur when the total cold rolling rate exceeds 40%. %, no side cracks occurred. Side trimming may be performed after heat treatment, but the shape of the plate after heat treatment is poor and it is difficult to perform side trimming to accurate dimensions, and the stress from side trimming remains on the edges, so side trimming is not recommended. It is desirable to perform this before heat treatment. In the cold rolling according to the second aspect, as in the first aspect, tension is applied to the cold-rolled titanium alloy material and the material is passed through the sheet. By repeating the process of claim 2, an ultra-thin plate of high-strength titanium alloy with a desired thickness can be obtained. However, in this method, the ultra-thin plate after rolling is wound into a coil shape, so the cold rolling of the cut plate is Unlike rolling, it is possible to manufacture long products with thin thickness, and the shape is also excellent. [Example] Ti-6Al-4V and Ti-6Al-2Mo shown in Table 1
The raw material is a thin plate of -4Zr-2Sn alloy cut into 380 mm width, the leader material is a 0.4 mm thick JIS class 2 (TP35C) cold rolled plate cut into the same width, and the ends are butted together using a TIG welder. It was made into a coil by welding. A schematic diagram of the manufactured coil is shown in FIG. 3. Figure 3a shows a pure titanium plate for a leader on the front and back of a test metal thin plate, which is made into a coil by TIG welding. Since it is about 25mm deep, it is the range minus 50mm from the length of the test gold plate. In addition, in b, specimen metal plates A and B were first butted and joined by TIG welding, and pure titanium plates for the leader were butted before and after that, and coiled by TIG welding, and the cold rolling range was the same as in a. , pure titanium and

[Table] Approximately 25 mm from the joint of the test metal plate to the test metal side, and the weld between the test metal plate and the test metal plate in the middle was cold rolled. The test metal plates A and B used in this coil production were of the same type. The coil thus produced had very good setting properties on the reel of a Sendzimir rolling mill. For cold rolling, a Sendzimir rolling mill with alloy rolls with a work roll diameter of 55 mmφ was used, and the initial tension was set to 10 kg/
mm ² , shape is corrected with a total load of 20Ton, and the load is 5To.
The rolling load was increased in increments to a total cold rolling rate of 35%. The reason why the load was increased in 5Ton increments was because of the tension.
This is to prevent deterioration in shape due to unbalanced load and to prevent constriction associated with this. To prevent edge cracking from occurring in the cold-rolled coil, slit both edges of the coil to a width of 3 mm on each side, wash the rolling oil with a solvent, and then wind the coil loosely.
Vacuum annealing was performed at 830°C for 1 hour. Then, the total cold rolling rate was set to 35 to 40%, and the cycle of → slitting → vacuum annealing was repeated for two cycles.
An ultra-thin titanium alloy plate of 0.1 mmt x 375mmW x C was manufactured. The properties of the manufactured titanium alloy ultrathin plate are shown in Table 2, which fully satisfies AMS 4911K, and
We manufactured titanium alloy foil plates with very high precision, ensuring flatness of 0.5mm/500mm in terms of shape, and thickness variation of approximately ±5μm. The produced ultra-thin plates have been applied to honeycomb materials for aircraft, and the results have been good, and the excellent properties of titanium alloys such as high corrosion resistance, high specific strength, and non-magnetic properties are expected to be used in space and ocean exploration, which are expected to be actively developed in the future. We believe that we can make a significant contribution to fields that use .

[Table] [Results of the Invention] By carrying out the present invention, it is possible to efficiently produce a cold-rolled sheet of high-strength titanium alloy that has a beautiful surface, excellent dimensional accuracy, and is thin in thickness.

[Brief explanation of drawings]

Figure 1 shows the relationship between the occurrence of edge cracks, rolling tension and total cold rolling reduction during cold rolling of titanium alloy sheets.
A diagram showing an example of the effect of side trimming of a 2Zr-2Sn alloy plate, and FIG. 3 is an explanatory diagram of the configuration of a coil in an example. It is.

Claims (1)

[Claims] 1. Pure titanium leader coils are welded to the front and rear parts of a titanium alloy plate, and the leader coils are wound around tension reels provided at the front and rear sides of a cold rolling mill, respectively. A method for cold rolling ultra-thin titanium alloy sheets, characterized by applying tension to the titanium alloy sheet through a leader coil and rolling it through the sheet at a total cold rolling rate of 40% or less. 2 A cold-rolled titanium alloy material having pure titanium leader coils on the front and rear parts is subjected to side trimming and annealing, and the leader coils are attached to tension reels provided on the front and rear surfaces of the cold-rolled material. The treatment process involves winding each titanium alloy plate, applying tension to the titanium alloy plate through a leader coil, and rolling it through the plate at a total cold rolling rate of 40% or less.
A method for cold rolling ultra-thin titanium alloy sheets, characterized by repeating the process once or twice or more.