JPH0359761B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention enables effective compression of the internal voids of the slab and reduces width fluctuations when reducing the thickness of the slab using a press. The present invention relates to a method and apparatus for reducing the thickness of a slab that can improve production efficiency.

[Prior Art] Conventionally, as shown in Fig. 9, thickness reduction by a press is performed by providing upper and lower anvils a and b that can be raised and lowered, and moving the slab S intermittently in the direction of arrow c. , b are raised and lowered to perform thickness reduction.

[Problems to be solved by the invention] However, with the means shown in FIG. 9 above,
Because the slab is rolled down to a predetermined thickness in one press using a flat anvil in the longitudinal direction of the slab, uneven compression occurs in the longitudinal direction of the slab, resulting in internal voids d.
There were problems such as not being able to effectively press the slab S, and furthermore, the fluctuation in the width of the slab S becoming large.

The present invention has been made in view of the above-mentioned circumstances, with the object of making it possible to effectively compress the internal voids of slabs, reducing width fluctuations, and improving production efficiency.

[Means for Solving the Problems] In the present invention, when reducing the thickness of a slab using a press, the thickness reduction is performed by performing step compression using an anvil provided with step portions having different heights in the slab advancing direction.

[Function] Therefore, in the present invention, the thickness is not reduced to a predetermined thickness by one press, but the thickness is reduced to a predetermined thickness by a number of presses corresponding to the number of stages of the anvil, and as a result, the inside of the slab The gap is effectively crimped and width variations are reduced.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention, in which numerals 1 and 2 indicate upper and lower anvils that can be raised and lowered. The upper and lower anvils 1 and 2 are provided with steps 3 and 4 in the slab advancing direction,
Height of upper and lower anvils 1 and 2 on the upstream side in the direction of slab movement
H ₁ is formed lower than the height H ₂ of the upper and lower anvils 1 and 2 on the downstream side in the slab advancing direction. R is the radius of curvature of the corner portions of the upper and lower anvils 1 and 2.

When the thickness is reduced by such upper and lower anvils 1 and 2, the slab S is reduced in thickness from T ₁ to T 2 by the height H ₁ portion of the upper and lower anvils 1 and ₂ in the first press, The thickness is reduced from the thickness T ₂ to a predetermined thickness T ₃ by the next press. By compressing the steps in this manner, the internal voids of the slab S are effectively compressed, and fluctuations in the slab width are reduced.

Next, experimental results will be explained with reference to FIGS. 2 to 5, when the thickness reduction was performed by the means of the present invention and when the thickness reduction was performed by the conventional means shown in FIG.

In both the means of the present invention shown in FIG. 1 and the conventional means shown in FIG. ₉ , as shown in _FIG . Anvil feed amount L ₀ as shown in the figure
Gaps 5 are formed in the slab S by machining at smaller intervals L, and the thickness reduction is performed by varying the slab thickness T ₃ at the exit side of the device, and the thickness reduction ratio and the void remaining ratio are determined as shown in Fig. 4. The relationship between ρ was determined, and the relationship between the thickness reduction rate and the width variation rate η was determined as shown in FIG. Here, the void remaining ratio ρ is the average of all voids expressed as ρ = h ₁ − _{h 2} /h ₁ when the height h ₁ of the void 5 at the entrance side of the device is reduced to h ₂ after thickness reduction. The width fluctuation rate η is the maximum plate width of the slab S at the exit side of the equipment, Wmax.
When the minimum plate width is Wmin., it is expressed as η=Wmax.−Wmin./W ₁ ×100.

In Fig. 4, curve A shows the void remaining ratio when thickness reduction is performed by the means of the present invention, and curve B shows the void remaining ratio when thickness reduction is performed by the conventional means shown in Fig. 9. It shows. From the graph in FIG. 4, it can be seen that as the thickness reduction rate increases, the void remaining ratio when the thickness reduction is performed by the means of the present invention is significantly reduced compared to the void remaining ratio when using the conventional means. it is obvious.

In FIG. 5, curve A shows the width variation rate when thickness reduction is performed by the means of the present invention, and curve B shows the width variation rate when thickness reduction is performed by the conventional means. From the graph in FIG. 5, it is clear that as the thickness reduction rate increases, the width variation rate when the means of the present invention is used is much lower than the width variation rate when the conventional means shown in FIG. 9 is used. It is.

In addition, if the front and rear ends of the slab S are compressed by the step compression described above without taking any means, the heights of the upper and lower anvils 1 and 2 will change as shown in FIG.
If the biting width at the part _H2 is small, the elongation of the surface layer of the slab S becomes large, resulting in a fish tail 6.
is formed, and this fishtail 6 needs to be cut later as shown by the dotted line 7, which poses a problem of lowering the product yield.

Therefore, in the tip compression of the slab S, the seventh
As shown in the figure, during compression, the engagement width L ₁ of the slab S at the height H ₂ section is set to the maximum so that the tip of the thickness T ₃ section substantially coincides with the front end of the height H ₂ section.

In addition, when compressing the rear end of the slab S, as shown in Figure 8, the rear end of the _3rd part of the thickness T is
The remaining width L ₂ of the rear end compressed by the height H ₁ part is set to the maximum so that it approximately coincides with the rear end part of the H _{2 part} .

As a result of the above, the front and rear ends of the slab S are pressed in the same way as when pressed with a flat anvil, and by pushing and stretching the entire thickness of the slab S, it is possible to prevent the occurrence of fish tails. Thereby, product yield can be improved. In order to prevent the formation of fishtails at the front and rear ends of the slab, the width W 2 at the height H ₂ should be made _larger as appropriate than the width W ₁ at the height H ₁ , as shown in FIG. This allows for easy adjustment.

In addition, in the embodiment of the present invention, the case where the step compression is performed by setting the step of the anvil in two steps has been explained, but it should be noted that it is possible to use any number of steps as long as it is two or more steps and has a finite step (in this case, the anvil has n steps). Then, the slab is pressed down to the specified thickness by n presses.)
It goes without saying that other changes may be made without departing from the gist of the present invention.

[Effects of the Invention] According to the slab thickness reduction method and apparatus of the present invention, step compression is performed using an anvil provided with steps in the slab advancing direction, so uneven compression is reduced and slab internal voids are reduced. As the width decreases, the width variation also decreases, which improves product quality and yield, and also improves production efficiency.Furthermore, the step part of the anvil is smoothly curved, so the material does not disintegrate during rolling. The flow is smooth and there is little variation in plate width or irregularities in the thickness direction, which also contributes to improving product quality.Furthermore, since the anvil is a one-piece piece, burrs occur at the step part of the rolled slab. Therefore, various excellent effects can be achieved, such as making it possible to operate under high pressure and further improving production efficiency.

[Brief explanation of drawings]

Fig. 1 is a side view of an embodiment of the slab thickness reduction method and apparatus of the present invention, Fig. 2 is a perspective view showing slab dimensions when experiments are conducted using the means of the present invention and conventional means, and Fig. 3 The figure is a side view of the same void spacing, Figure 4 is a graph of experimental results showing the relationship between thickness reduction rate and void survival rate, and Figure 5 shows the relationship between thickness reduction rate and width variation rate. Graphs of experimental results. Figure 6 is a side view of a fishtail caused by step compression. Figure 7 is a side view of compression to prevent a fishtail from occurring at the tip of the slab. Figure 8 is a side view of a fishtail produced at the rear end of the slab. FIG. 9 is a side view of a conventional example. In the figure, 1 indicates the upper anvil, 2 indicates the lower anvil, and S indicates the slab.

Claims (1)

[Claims] 1. In a method for reducing the thickness of a slab using a press, the slab is compressed by an integrated anvil that has stepped portions with different heights in the direction of slab movement, and the corner portions of the stepped portions are formed into smooth curves. A method for reducing the thickness of a slab, characterized by reducing the thickness of the slab. 2. In a device for reducing the thickness of a slab using a press, an integrated anvil is provided with stepped portions with different heights in the slab advancing direction, and the corner portions of the stepped portions are formed in a smooth curved shape, and can be moved toward and away from the slab plane. A slab thickness reduction device characterized by being provided in.