JPS631121B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method and apparatus for hot rolling steel bars and wire rods. In conventional rolling of steel bars and wire rods, several driven horizontal rolling mills are arranged in tandem to roll several strands, or horizontal rolling mills and vertical rolling mills each driven are arranged alternately to roll one strand. The majority are those that perform rolling. In rolling by a rolling mill group consisting of only horizontal rolling mills, it is necessary to rotate the rolled material by 90 degrees around the longitudinal direction between the rolling mills, and considering workability when changing rolls and guides, etc. The distance between each rolling mill is approximately 3 to 5 m, and the site area occupied by the entire rolling mill group becomes large. In addition, since the rolled material is twisted by 90 degrees, defects such as sagging and folding are likely to occur in terms of quality. On the other hand, the rolling method of one strand using a rolling mill group in which horizontal rolling mills and vertical rolling mills, both of which are driven, are arranged alternately, yields a steel bar or wire rod of better quality than rolling with only a horizontal rolling mill group. The equipment cost of a rolling mill is very high, about 3 to 4 times that of a horizontal rolling mill, and therefore the equipment cost of the rolling mill group as a whole is also considerably higher than that of the horizontal rolling mill group. Furthermore, considering that the area occupied by the vertical rolling mill's drive unit mounting column itself is larger than that of the horizontal rolling mill's drive unit, and considering the ease of work such as changing the rolls and guides of the vertical rolling mill, this method is The spacing between rolling mills is longer than in a system using only horizontal rolling mills. (Problems to be Solved by the Invention) One object of the present invention is to provide a method and apparatus for hot rolling steel bars and wire rods that overcomes the drawbacks of the prior art described above. More specifically, another object of the present invention is to provide a method and apparatus for hot rolling steel bars and wire rods that enable a compact rolling facility with relatively low equipment costs and a small footprint. (Means for Solving the Problems) The gist of the present invention is to provide a method for hot rolling steel bars and wire rods through a horizontal rolling mill, a vertical rolling mill, and a horizontal rolling mill. After rolling the rolled material, the rolled material is rolled by a vertical rolling mill consisting of non-driven vertical rollers placed behind the horizontal rolling mill, and then an electric motor further placed behind the vertical rollers. This is a method for hot rolling steel bars and wire rods, characterized in that the above-mentioned rolling material is rolled by a driven horizontal rolling mill. In one embodiment of the present invention, the rolling by the vertical rolling mill consisting of non-driven vertical rollers may be carried out under the action of compressive force generated in the rolled material by rolling by the preceding horizontal rolling mill. good. Furthermore, rolling by the vertical rolling mill consisting of the above-mentioned non-driven vertical rollers involves the compression force generated in the rolled material by the rolling by the earlier stage horizontal rolling mill and the tensile force produced in the rolled material by the later stage horizontal rolling mill. It may also be carried out under the influence of According to one embodiment of the present invention, the cross-sectional reduction rate of the rolled material per pass by each horizontal rolling mill is between 20 and 30.
%, and a pass schedule hot rolling method is provided in which the cross-sectional reduction rate of the rolled material per pass by vertical rollers is 10 to 20%. Cross section reduction rate per pass by horizontal rolling mill is 20
If it is less than %, the rolling efficiency will be poor and many passes of rolling will be required. Moreover, the tensile force of the material between the horizontal rolling mill and the vertical rollers at the later stage becomes insufficient. On the other hand, if the area reduction rate exceeds 30%, it will generally be difficult to cause the material to bite into the horizontal rolling rollers. If the cross-sectional reduction rate of the rolled material per pass by the vertical rollers is less than 10%, the rolling efficiency will be poor as described above, and a large number of passes will be required.
In addition, in the case of rolling by more than 20%, the compressive force generated between the material and the horizontal rolling mill in the previous stage may exceed the buckling limit of the material. Furthermore, when performing grooveless rolling, a trough is installed that can restrict the movement of the rolled material in four directions between the vertical rollers and the horizontal rolling mill.
Even if the occurrence of buckling is minimized, if the area reduction rate exceeds 20%, it will become extremely difficult to bite the material into the vertical rollers, or slight buckling will occur, causing a slip phenomenon and making rolling impossible. There is a risk that it will happen. Therefore, in the hot rolling method of the present invention, the cross-sectional reduction rate of the rolled material per pass by each horizontal rolling mill is 20 to 20.
30%, and the cross-sectional reduction rate of the rolled material per pass by the vertical rollers is preferably 10-20%. Furthermore, according to one embodiment of the invention, the vertical rollers are arranged as close as possible to the preceding horizontal rolling mill. This is to prevent as much as possible buckling of the rolled material due to the compressive force generated in the rolled material between the vertical rollers and the preceding horizontal rolling mill, and also to reduce the area occupied by the entire equipment. This is only possible because the vertical rollers are not driven. Therefore, from another aspect of the present invention, the first
The horizontal rollers constituting the horizontal rolling mill, the vertical rollers constituting the vertical rolling mill, and the horizontal rollers constituting the second horizontal rolling mill are assembled into the first housing in this order along the rolling direction.
This hot rolling apparatus for steel bars and wire rods is characterized in that two horizontal rollers are driven by electric motors, and the vertical rollers are non-driven. (Operation) The present invention will be explained in more detail with reference to the accompanying drawings. FIG. 1 shows part of a group of rolling mills for hot rolling steel bars and wire rods according to the prior art, in which horizontal rolling mills and vertical rolling mills, both of which are driven by electric motors, are arranged alternately. It is a schematic explanatory diagram in which reference numbers 1 and 3 indicate horizontal rolling mills, and 2 indicates a vertical rolling mill. The rolling material 4 is first rolled in a horizontal rolling mill 1, then sequentially rolled in a vertical rolling mill 2 and then a horizontal rolling mill 3. However, in the conventional rolling equipment shown in FIG. 1, both the horizontal rollers and the vertical rollers are driven by electric motors, so the distance between each rolling mill is L ₁ ,
L ₂ becomes considerably large. This is usually 3-5m
This depends on the overall capacity of the rolling mill, the guide change, the workability of misrolling, the size of the electric motor and reducer, and especially the size of the vertical rolling mill's drive system. In addition,
The increased thickness of the rolled material 4 leaving the vertical rolling mill 2 is due to the material flowing partially in the roll length direction, ie in the thickness direction of the rolled material 4, due to the reduction by the vertical rolls. Here, in order to apply the method of the present invention in which the vertical rolling mill is a non-drive type to the above-mentioned conventional rolling equipment, the problem with the equipment is that the reduction gear of the vertical rolling mill 2 and the vertical rolls must be connected. It is enough to remove the spindle coupler spring. FIG. 2 shows a first step for implementing the method of the invention.
An example of modifying the equipment shown in the figure is shown. The vertical rolling mill 2 of FIG. 1 has its spindle coupling removed and functions as a non-driven vertical roller 2'. According to the apparatus modified in this way, first, at the start of rolling, the horizontal rolling mill 1 preferably rolls 20 to 30
The rolled material 4, which has been rolled with a reduction in area of Rolling is carried out with a reduction in area of preferably 10-20%. As shown in FIG. 2, a trough 5 is provided between the horizontal rolling mill 1 and the vertical rollers 2' so as to restrict the movement of the rolled material 4 around the entire circumference, thereby preventing buckling of the rolled material 4. are doing. After rolling starts, the compressive force applied to the rolled material 4 by the horizontal rolling mill 1, or the compressive force and the tensile force applied to the rolled material 4 by the horizontal rolling mill 3, further increases the When the amount of rolling by the vertical rollers is extremely small, rolling proceeds substantially by the driving forces of both horizontal rolling mills 1 and 3. Regarding the relationship between the horizontal rolling mill 1 and the subsequent horizontal rolling mill 3, it is more preferable that before the rear end of the rolled material 4 passes through the horizontal rolling mill 1, the leading end is caught in the horizontal rolling mill 3. Rolling is carried out with a reduction in area of 20-30%. Therefore, even if the rear end of the rolled material 4 passes through the horizontal rolling mill 1 at the end of rolling and no compressive force is generated between the horizontal rolling mill 1 and the vertical rollers 2', the vertical rollers 2' A tensile force is created in the rolled material 4 between the horizontal rolling mill 3 and the horizontal rolling mill 3, which allows the rolling by the non-driven vertical rollers 2' to be completed. FIG. 3 is a schematic explanatory diagram showing a part of a rolling mill group in which only horizontal rolling mills for several strands are arranged according to the prior art. The rolled material 4 is passed through horizontal rolling mills 6, 7,
Rolling is repeated in the order of 8, alternating between twisting by 90 degrees and not twisting at all. However, according to this method, as mentioned above, rolling is repeated by rotating the roll through 90 degrees, resulting in low rolling efficiency and quality defects such as sagging and folding. Here, since the method of the present invention uses only vertical rollers with a simple structure due to non-drive, the third
The above-mentioned horizontal rolling mill group for several strands shown in the figure can also be modified simply by installing non-driven vertical rollers 9 and 10 downstream of the horizontal rolling mills 6 and 7 as shown in FIG. Can be applied. In FIG. 4, a non-driven vertical roller 9 is placed as close as possible to the rear of the horizontal rolling mills 6 and 7 of FIG.
and 10 are arranged. In the illustrated example, the horizontal rolling mill 7 also serves as a horizontal rolling mill that applies tension to the rolled material between the vertical rollers 9 and a horizontal rolling mill that applies compressive force to the rolled material between the vertical rollers 10. The stiffness of the vertical rollers 9 and 10 is approximately equal to the stiffness of the horizontal rolling mills 6 and 8. According to the method of the present invention, when rolling with the equipment shown in FIG. 4, it is not necessary to twist the rolled material by 90 degrees, and the quality of the rolled material can be improved by continuing rolling. Although the case of one strand is shown in FIG. 4, the number of vertical rollers 9 and 10 equal to the number of strands is
By increasing the number of sets, rolling of several strands becomes possible according to the present invention. This is horizontal rolling mill 6,
Although it depends on the size of the spacings L ₃ and L ₄ of 7 and 8, it is usually possible to roll at least two strands. In the case of rolling two strands, horizontal rolling mills 6 and 7 each have two vertical rollers 9 and 10.
It may be installed between 7 and 8. When the method of the present invention is carried out using the rolling equipment shown in Fig. 4, the cross section of the material is made larger than that in the conventional horizontal rolling method, improving the rolling yield, and rolling with a larger overall area reduction. It can be performed. Next, FIG. 5 shows an example of a hot rolling apparatus designed as an apparatus capable of most efficiently carrying out the rolling method of the present invention. The hot rolling apparatus 11 shown in FIG. 5 has motor-driven horizontal rollers 13 and 14 attached to the front and rear parts of the same housing 12, respectively, and a non-driven vertical roller 15 arranged in the center. The reason why it is possible to install three sets of rollers in the same housing in this way is that the structure of the vertical rollers 15 is extremely simple because they are not driven. The rolled material 4 is rolled by the horizontal rollers 13 with a reduction in area of 20 to 30%, and immediately bitten by the vertical rollers 15, rolled with a reduction in area of 10 to 20%, and then rolled by a motor-driven horizontal roller. 14 with a reduction in area of 20 to 30%. Due to the close proximity of the horizontal rollers 13 and vertical rollers 15, the possibility of buckling of the rolled material 4 is less than when a conventional rolling mill is modified according to the invention. Furthermore, since the rolling apparatus 11 is extremely compact, the area occupied by the entire rolling equipment including the hot rolling apparatus 11 is extremely small. This can be said to be a significant practical advantage when installing new rolling equipment. Next, an example of hot rolling a material having cross-sectional dimensions of 115×115 (mm) using the rolling mill group shown in FIG. 2 according to the method of the present invention will be described below. Horizontal rolling mills achieve a cross-section reduction of 20-30%, respectively, while that with vertical rollers is also 10-30%.
20% is ensured, and the total cross-sectional reduction rate due to these rollings is approximately 50%. Despite this large amount of rolling, no defects were observed in terms of quality, and the mechanical properties of the resulting wire were superior to those obtained by the conventional method using driven vertical rollers. Ta.

[Table] (Effects of the invention) As detailed above, according to the method and apparatus of the present invention, the entire rolling equipment occupies a small area, and the use of vertical rollers improves the properties of the product. Since it is non-driven, the structure is simplified, inspection and maintenance are easy, and power consumption can be reduced. Furthermore, the scope of the present invention is not limited only to what is shown in the accompanying drawings, but should be determined based on the claims. For example, rolling of steel bars and wire rods by a combination of a horizontal rolling mill and non-driven vertical rollers is also within the scope of the present invention.

[Brief explanation of the drawing]

Figure 1 is a schematic explanatory diagram of a part of hot rolling equipment for steel bars and wire rods according to the conventional technology in which horizontal rolling mills and vertical rolling mills are arranged alternately; Figure 2 is a partially modified version of the equipment shown in Figure 1. FIG. 3 is a schematic illustration of a part of a horizontal rolling group of several strands according to the prior art; FIG. A schematic explanatory diagram showing an example in which the equipment shown in FIG. 3 has been modified in order to implement the method of the present invention; and FIG. 5 is a schematic explanatory diagram of a hot rolling apparatus designed to implement the rolling method of the present invention. It is. 1, 3, 6, 7, 8, 13, 14...Horizontal rolling mill, 2...Horizontal rolling mill, 2', 9, 10, 15...
...Vertical roller, 4...Rolled material, 6...Trough.

Claims (1)

[Claims] 1. A method for hot rolling steel bars and wire rods through a horizontal rolling mill, a vertical rolling mill, and a horizontal rolling mill,
After rolling the rolled material by an electric motor-driven horizontal rolling mill, the rolled material is rolled by a vertical rolling mill consisting of non-driven vertical rollers arranged behind the horizontal rolling mill, and then A method for hot rolling steel bars and wire rods, characterized in that the above-mentioned rolled material is rolled by a horizontal rolling mill driven by an electric motor further disposed at the rear. 2. The method according to claim 1, wherein the rolling by the vertical rolling mill consisting of non-driven vertical rollers is carried out under the action of compressive force generated on the rolled material by rolling by the preceding horizontal rolling mill. . 3. Rolling by the above-mentioned vertical rolling mill consisting of non-driven vertical rollers involves the effects of compressive force generated on the rolled material by rolling by the earlier stage horizontal rolling mill and tensile force produced on the rolled material by the later stage horizontal rolling mill. 2. A method according to claim 1, characterized in that it is carried out by: 4 Incorporating the horizontal rollers constituting the first horizontal rolling mill, the vertical rollers constituting the vertical rolling mill, and the horizontal rollers constituting the second horizontal rolling mill in this order along the rolling direction into the housing of 1; A hot rolling apparatus for steel bars and wire rods, characterized in that the two horizontal rollers are driven by an electric motor, and the vertical roller is non-driven.