JP2001353501A - Method and equipment for rolling with four rolls - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the parallelism, perpendicularity and dimensional accuracy of the radius of curvature of the corners of a wire and bar having square-shaped cross section. SOLUTION: This method for rolling the wire and bar 1 into a square-shaped cross section with two 4-roll mils 3, 4 which are installed in the rolling direction has: a stage where the four sides of the square-shaped cross section are rolled with the 4-roll mill 3 provided with flat rolls; and a stage where the radius of the four corners are rolled with the 4-roll mill 4 provided with caliber rolls corresponding to the radius of curvature of the four corners of the square-shaped cross section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for rolling a wire rod having a rectangular cross section, and more particularly to a method and a rolling method suitable for rolling a wire rod having an aspect ratio of less than 1.3. Equipment related.

[0002]

2. Description of the Related Art As a conventional rolling method of this kind, a material to be rolled by a row of rough rolling mills and a row of intermediate rolling mills is composed of, for example, two-roll rolling mills a and b as shown in FIG. 2. Description of the Related Art A method of rolling by a finish rolling mill train is known. That is, first, as shown in FIG. 7 (a), a two-roll rolling mill a provided with a caliber-equipped roll c having a semi-elliptical cross section is rolled into an elliptical cross section, and then, as shown in FIG. 7 (b). , A section R having a corner R (A) and a corner R (B)
The two-roll rolling mill b provided with the character-shaped caliber-equipped rolls d is used to obtain a wire rod having a rectangular cross section by rolling into a rectangular cross section.

[0003]

However, in the above-mentioned conventional rolling method, two two-roll rolling mills a and b are used.
Parallelism (parallelism of two opposing sides of a rectangular cross section) and a right angle (a right angle of an intersection formed by extending adjacent sides of a rectangular cross section) Angle) and the dimensional accuracy of the corners R (the dimensional accuracy of the radius of curvature of the four corners of the quadrangular section) are low.
There is an inconvenience that it is difficult to work with high dimensional accuracy in which corner corners become pin angles (90 degrees).

The present invention has been made to solve such inconveniences, and can improve the parallelism, squareness, and dimensional accuracy of the corner R of a wire rod having a square cross section, thereby improving the rearward accuracy. It is an object of the present invention to provide a four-roll rolling method and a rolling equipment capable of obtaining a scribed steel wire with high dimensional accuracy in the die drawing step.

[0005]

In order to achieve the above object, a four-roll rolling method according to the first aspect of the present invention finishes a wire rod into a quadrangular cross section by using a plurality of four-roll rolling mills arranged in a rolling direction. A method of rolling, in which a four-roll rolling machine having a flat roll is used to roll four sides having a rectangular cross section, and a four-roll rolling including a roll with a caliber corresponding to four corners R of the four corners of the rectangular cross section. Rolling the four corners R by a mill.

[0006] The rolling equipment according to claim 2 is a rough rolling mill train,
In a rolling equipment in which an intermediate rolling mill row and a finishing rolling mill row are arranged in this order and the wire bar is rolled into a rectangular cross section, the finishing rolling mill row is provided with flat rolls for rolling four sides of the rectangular cross section. 4 roll rolling mill and 4
4 equipped with a roll with caliber for rolling the corner R of the corner
And a roll rolling mill.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory schematic plan view for explaining a rolling method which is an example of an embodiment of the present invention.
FIG. 3 is an explanatory view for explaining a rolling step by a four-roll rolling mill provided with flat rolls. FIG. 3 is an explanatory view for explaining a rolling step by a four-roll rolling mill provided with rolls with calibers. Is an explanatory diagram for explaining another embodiment of the present invention, and FIG. 6 is a graph showing a dimensional accuracy distribution of a corner R in a conventional example and an example of the present invention.

In FIG. 1, reference numeral A denotes a heating furnace, B denotes a row of rough rolling mills, C denotes a row of intermediate rolling mills, and both the row of rough rolling mills B and the row of intermediate rolling mills C are in the traveling direction (rolling direction) of the bar 1. And a plurality of two-roll rolling mills 2 arranged in a state where the rolling direction is orthogonal to the rolling direction. On the downstream side of the intermediate rolling mill row C, the steel bar 1 after passing through the intermediate rolling mill row C
Is arranged, for example, to roll into a square cross section having an aspect ratio of less than 1.3, and the finishing mill row D is arranged along a rolling direction. There are four 4-roll mills 3 and 4. Among the two four-roll rolling mills 3, 4, the four-roll rolling mill 3 arranged on the upstream side includes a horizontal roll pair 3a, 3a and a vertical roll pair 3a.
b, 3b, and each roll surface is a flat surface. On the other hand, the two pairs of rolls 4a, 4a, 4b, 4b of the four-roll mill 4 arranged on the downstream side are at 45 ° to the two pairs of rolls 3a, 3a, 3b, 3b of the four-roll mill 3. The calibers 5 are arranged so as to be out of phase with each other and correspond to the four corners R of the rectangular cross section on each roll surface.

Then, the steel bar 1 discharged from the heating furnace A is rolled by the rough rolling mill row B and the intermediate rolling mill row C into a substantially circular cross section or a substantially square cross section, and then the tail end passes through the intermediate rolling mill row C. As shown in FIG. 2, the bar steel 1 having been subjected to the four-roll rolling mill 3 on the upstream side of the finishing mill row D is used as a pair of flat rolls 3 a, 3 a, 3 b, 3 b to form a square bar 4.
The side is then rolled and then, as shown in FIG. 3, two pairs of caliber-equipped rolls 4a, 4a,
The four corners R of the rectangular cross section are rolled by 4b, 4b, whereby the steel bar 1 is rolled into a rectangular cross section having an aspect ratio of, for example, less than 1.3.

Thus, in this embodiment, one of the four
The two flat roll pairs 3a, 3a,
3b, the four sides of the rectangular cross section are constrained by 4b, and the other four roll mill 4 is provided with four pairs of caliber-equipped rolls 4a, 4a, 4b, 4b to form four corners of the rectangular cross section. Since the rolling is performed with the R constrained, it is possible to obtain a wire rod having a rectangular cross section with high parallelism, squareness and high dimensional accuracy of the corner R. As a result, the four corner corners can be obtained in the subsequent die drawing process. It is possible to obtain a steel wire having only a high dimensional accuracy in which the portion has a pin angle (90 degrees).

In the above embodiment, the case where the four-roll rolling mill 3 having the flat roll surface is arranged on the upstream side is taken as an example. However, it is not always necessary to adopt such an arrangement. Even when the four-roll rolling mill 4 having the flat roll surface is arranged on the upstream side and the four-roll rolling mill 3 having the flat roll surface is arranged on the downstream side, the same operation and effect as in the above embodiment can be obtained. Can be.

In this case, the steel bar 1 whose tail end has passed through the intermediate rolling mill row C is used as shown in FIG. 4 to form two sets of caliber-equipped roll pairs 4a, 4a, 4a of the upstream four-roll rolling mill 4. 4
b, 4b to roll four corners R of the rectangular cross section, and then roll four sides of the rectangular cross section by two pairs of flat rolls 3a, 3a, 3b, 3b of the downstream four-roll rolling mill 3. Thereby, the steel bar 1 is rolled into, for example, a rectangular section having an aspect ratio of less than 1.3.

In the above embodiment, the case where the finishing rolling mill row D is composed of two four-roll rolling mills has been described. However, the number of finishing rolling mill rows need not be limited to two. It is possible to arrange the two rolls at the first stage as a four-roll rolling mill with flat rolls, and at the latter stage as a four-roll rolling mill with rolls with calibers.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the case where a wire rod having a rectangular cross section is rolled using two two-roll rolling mills a and b shown in FIG. 7 (conventional example).
Dimensional accuracy of corners R at four corners, respectively, when a wire rod having a rectangular cross section is rolled using two four-roll rolling mills 3 and 4 shown in FIGS. 2 and 3 (example of the present invention). FIG. 6 shows the result of organizing the distribution. The rolling conditions such as the material and the cross-sectional dimensions were the same except for the rolling mill used, and the number of times of rolling was N = 23 in both the conventional example and the present invention. Further, in the conventional example, referring to FIG. 7, a corner R constrained by the caliber is (A), and a corner R not constrained by the caliber is (B). As is clear from FIG.
In the conventional example, the dimensional accuracy varies in the range of 1.8 to 3.4 mm of the corner R, and it can be seen that the dimensional accuracy of the corner R (B), which is not constrained by the caliber, particularly varies greatly. On the other hand, in the example of the present invention, the corner R
It can be seen that the variation is small in the range of 2.2 to 2.6 mm, and that the corner R is almost concentrated to 2.4 mm, and that high-dimensional precision rolling can be performed.

According to the conventional method, about 0.5% of dimensional defects that do not satisfy the strict standards of parallelism and squareness occur. However, in the present embodiment, the rate of defective products is reduced to 0.1%. %.

[0016]

As is apparent from the above description, according to the present invention, the parallelism, the squareness and the dimensional accuracy of the corner R of the wire rod having a rectangular cross section can be improved, so that the die is later pulled out. The effect is obtained that a steel wire can be obtained with only high dimensional accuracy in the process.

[Brief description of the drawings]

FIG. 1 is an explanatory schematic plan view for explaining a rolling method as an example of an embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining a rolling process by a two-roll rolling mill.

FIG. 3 is an explanatory diagram for explaining a rolling process by a four-roll rolling mill.

FIG. 4 is an explanatory diagram for explaining a modification of a rolling process by a two-roll rolling mill.

FIG. 5 is an explanatory diagram for explaining a rolling process by a four-roll rolling mill.

FIG. 6 is a graph showing a precision distribution of a dimension of a corner R in a conventional example and an example of the present invention.

FIG. 7 is an explanatory view of a conventional rolling method, and is an explanatory view for explaining a method of rolling a wire rod having a rectangular cross section by two two-roll rolling mills.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Steel bar (wire bar) 3 ... 4 roll rolling mill 3a ... Flat roll 3b ... Flat roll 4 ... 4 roll rolling mill 4a ... Roll with caliber 4b ... Roll with caliber 5 ... Caliber

Continued on front page F term (reference) 4E002 AC12 AC14 BB05 BB06 BB07 CB01 CB09 4E016 AA04 AA05 BA05 BA10 CA08 DA06

Claims (2)

[Claims] 1. A method of finishing rolling a wire rod into a rectangular cross section by a plurality of four roll rolling mills arranged in a rolling direction, wherein the four sides of the rectangular cross section are formed by a four roll rolling mill provided with flat rolls. And a step of rolling the four corners R by a four-roll rolling machine having rolls with calipers corresponding to the four corners R of the quadrangular cross section. Rolling method. 2. A rolling mill in which a rough rolling mill row, an intermediate rolling mill row, and a finishing rolling mill row are arranged in this order to roll a wire rod into a rectangular cross section, wherein the finishing rolling mill row has a rectangular cross section. A rolling facility comprising: a four-roll rolling mill having flat rolls for rolling four sides; and a four-roll rolling mill having rolls with calipers for rolling four corners R of a quadrangular cross section.