CN1818095A - Method and mould for producing face-centered cubic metal plate with fine grain - Google Patents

Abstract

The invention discloses a method and a mold for preparing a face-centered cubic metal fine-grained plate. The method comprises making the pressure-receiving surface of the plate to be prepared form an angle of θ of 45-80° with the pressure direction, and then applying pressure to the plate to be prepared. . The mold required to realize the method has an upper mold and a lower mold, and the surface of the upper mold and the lower mold contacting the metal sheet is an inclined plane, and the inclined plane forms an included angle of 45-80° with the direction of force application. The invention can make the plate to be prepared not only receive the force perpendicular to the compression direction, but also receive the shear force parallel to the surface of the slab during the compression process, which not only greatly reduces the grain size, but also can form in the plate The strong shear texture increases the content of ND∥<111> texture, thus greatly improving the deep drawing performance of face-centered cubic metal sheets, especially suitable for the production of aluminum and aluminum alloy sheets.

Description

Method and mold for preparing face-centered cubic metal fine-grained sheet

technical field

The invention relates to a method and a mold for preparing a face-centered cubic metal fine-grained plate.

Background technique

At present, the preparation of metal sheets mainly includes hammer flat compression and rolling. Flat hammer compression causes the metal to undergo plane strain deformation, and rolling is an approximate plane strain deformation. Since the effects of the two are basically the same, rolling is more It is suitable for industrialized production, so the rolling method is usually used in the industry to produce metal sheets. The body-centered cubic metal sheets processed by this method, such as steel plates, have good deep drawing performance, and the plastic strain ratio r>1, while for face-centered cubic In the preparation of metal sheets, due to the inability to form a strong ND∥<111> texture component, the deep drawing performance of aluminum and aluminum alloy rolled sheets is poor, and the plastic strain ratio is very low, usually less than 0.8. In addition, the grain size of the plate obtained by rolling deformation is usually very coarse, and the size is often uneven, which cannot meet the organizational conditions required by superplasticity (the grain size must generally be less than 10 μm). Due to the limitation of the total deformation, the ordinary rolling method cannot obtain a very fine grain structure, and even if the rolling-based mechanical heat treatment is used, the grain size below 10 μm cannot be obtained. Taking the 1420 aluminum-lithium alloy as an example, the nominal composition is Al-5Mg-2Li2-0.1Zr. The initial grain structure is shown in Figure 1. The grains are flat, and the three dimensions of RD, ND, and TD are about 210μm, 15μm, 45μm. After hot rolling, its grain structure is shown in Figure 2. Although the grain size has been greatly reduced and some equiaxed grains have appeared, many grains are still flat, and its texture components are typical copper textures. , the occupancy rate of the {111} surface is almost zero, as shown in Figure 3. Taking high-purity aluminum as an example, the plate rolled by the traditional method has a grain size of about 500-600 μm, as shown in Figure 4. Therefore, the poor deep drawing performance of face-centered cubic metal sheets is an urgent problem to be solved.

Contents of the invention

The object of the present invention is to provide a method and mold for preparing face-centered cubic metal fine-grained plates, which can effectively improve the deep-drawing performance of the face-centered cubic metal plate and refine its grain structure.

The method for preparing the face-centered cubic metal fine-grained plate of the present invention comprises making the pressure-receiving surface of the plate to be prepared form an angle θ of 45-80° with the pressure direction, and then apply pressure to the plate to be prepared.

The mold for preparing the face-centered cubic metal fine-grained plate with the method of the present invention has an upper mold and a lower mold, and the surface of the upper mold and the lower mold contacting the metal plate is an inclined plane, and the inclined plane forms a θ of 45-80° with the direction of force application. angle.

In the present invention, the material (the plate to be prepared) is not only subjected to a force perpendicular to the compression direction, but also to a shear force parallel to the surface of the slab during the compression process, so that the strong shear strain is introduced into the flat hammer compression or compression of the slab. In plane strain compression, not only can more deformation energy be stored in the sheet, so that the grain size is greatly reduced, but also a strong shear texture can be formed in the sheet, and the content of ND∥<111> texture can be increased, especially The face-centered cubic metal can also greatly increase the normal ND∥<111> texture content of the plate surface, thus greatly improving the deep drawing performance of the plate, especially suitable for the production of aluminum and aluminum alloy plates.

Description of drawings

Figure 1 is a diagram of the initial grain structure of 1420 Al-Li alloy.

Fig. 2 is a diagram of the grain structure of a sheet of 1420 Al-Li alloy rolled by a traditional method.

FIG. 3 is a (111) pole figure of the sheet of FIG. 2. FIG.

Figure 4 is a diagram of the grain structure of high-purity aluminum rolled by conventional methods.

Fig. 5 is a schematic diagram of the first structure of the mold of the present invention.

Fig. 6 is a schematic diagram of the second structure of the mold of the present invention.

Fig. 7 is a schematic diagram of the third structure of the mold of the present invention.

Fig. 8 is a grain structure diagram of a 1420 aluminum-lithium alloy plate rolled by the method of the present invention.

FIG. 9 is a (111) pole figure of the plate described in FIG. 8 .

Fig. 10 is a grain structure diagram of a high-purity aluminum plate rolled by the method of the present invention.

Detailed ways

Embodiment one:

Fig. 5-Fig. 7 is three kinds of different shapes of mold of the present invention, all has upper die 2 and lower die 3, and the contact surface of upper die and lower die and metal slab is inclined-plane, and the angle between direction of application force and inclined-plane, The θ angle is 45°-80°, preferably between 50°-60°, and the metal slab 1 is placed between the upper mold 2 and the lower mold 3 during use.

Example two:

The initial slab is 8.5mm thick hot-rolled plate, which is 1420 aluminum-lithium alloy after smelting, semi-continuous casting, face milling, homogenization, and hot rolling. 1420 is a Russian wrought aluminum alloy grade.

The mold adopts any one of the molds shown in Figures 5-7, and the θ angle is selected as 60°.

The slab is placed between the molds (2, 3), and a suitable lubricant should be used between the mold and the metal slab. Apply a little pressure to keep the slab and mold in a stable position. Heat the mold and the slab to 300°C, keep it warm for 10 minutes, and press it with a strain of 10% per pass until the total deformation reaches about 90%. The dwell time between each pass is 6 seconds. Quenching to room temperature to preserve the high temperature structure. The compressed grain structure (longitudinal section) is shown in Figure 8, the grain size is greatly reduced, and the average grain size is about 3.5 μm. Figure 9 is the compressed {111} pole figure, it can be seen that the occupancy of {111} plane is much higher than that of the rolling plane deformation state. Make the aluminum-lithium alloy sheet have good deep drawing performance. According to common knowledge in the technical field, the present invention is also applicable to other aluminum alloys.

Example three:

The initial slab is a high-purity aluminum hot-rolled sheet, and its impurity content is about Fe 7×10 ^-8 -10×10 ^-6 , Si 7×10 ^-6 -10×10 ^-6 , Cu 30×10 ^-6 -40 ×10 ^-6 , the ingot was homogenized at 610°C for a long time, face milled, and then hot rolled to about 7mm. Use the mold shown in Figure 2, select θ = 55°, and the deformation temperature is 500°C.

Place the slab between the molds (2, 3) and apply a little pressure to keep the slab and mold in a stable position. Heat the mold and slab to 500°C, keep it warm for 10 minutes, and press it according to the strain amount of 10% in each pass until the total deformation reaches about 90%, and the residence time between each pass is 6 seconds. Its grain structure (longitudinal section) is shown in Figure 7, and the grain size is obviously smaller (compared with that rolled by the traditional process in Figure 4).

Therefore, the present invention can process face-centered cubic metal sheets such as aluminum and aluminum alloys with good deep drawing performance, and use the present invention to prepare other process parameters of face-centered cubic metal fine-grained sheets, such as heating temperature, holding time, and the temperature of each pass. There are no special requirements for the amount of pressing and the interval time, and the process parameters of traditional flat hammer compression can be used.

Claims (4)

1, a kind of method for preparing face-centered cubic metal plate with fine grain comprises the θ angle that the load face that makes sheet material to be prepared and pressure direction are 45-80 °, exerts pressure to sheet material to be prepared then.

2, method according to claim 1 is characterized in that described angle is 50-60 °.

3, a kind of mould with the described method preparation of claim 1 preparation face-centered cubic metal plate with fine grain is characterized in that having upper die and lower die, and the face that upper die and lower die contact described sheet metal is the inclined-plane, and this inclined-plane becomes 45-80 ° θ angle with application of force direction.

4, mould according to claim 3 is characterized in that described angle is 50-60 °.

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