JP2527283B2 - Round steel sizing rolling method - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to a material to be rolled which is rolled by the rolling mill train the upper stream side, of installed downstream of the rolling mill train
The present invention relates to a sizing rolling method for round bar steel, which is shaped into a plurality of dimensions by the sizing rolling machine .

[0002]

2. Description of the Related Art When sizing rolling is carried out, it is not necessary to replace it with a roll having a caliber corresponding to the diameter of the round steel bar to be shaped, but by simply adjusting the gap between the rolls for sizing rolling, the round steel bar having a plurality of diameters is adjusted. Can be manufactured, the rolling stop time required for changing the size according to the product diameter can be significantly reduced, and the dimensional accuracy of the formed round steel bar itself can be improved.

As a conventional sizing rolling method carried out for the above, a caliber having an arc with a diameter larger than the diameter of the raw material is used, and as shown in FIG.
A two-roll method (FIG. 3A) in which rolling is performed while shifting the rolling direction, a three-roll method (FIG. 3B) in which rolling is performed while shifting the rolling direction by a three-roll rolling mill, or a four-roll rolling machine A four-roll method (Fig. 3 (c)) in which rolling is performed by shifting the rolling direction is known. These methods are performed by a plurality of rolling mills of the same type as shown in the figure while changing the rolling direction. Sizing rolling is performed by rolling the pass.

[0004]

[SUMMARY OF THE INVENTION However, in the sizing rolling method, such as, and the size range of Do that round bar steel allow shaping by only changing the roll gap at the caliber of the same shape is a problem that narrow. Explaining in detail, comparing the shapes of the rolled material after passing the second pass in the sizing rolling by the two-roll method and the four-roll method, the cross-section of the two-roll method becomes a circle slightly close to a quadrangle, and the four-roll method Since the circle is a little like an octagon, the two-roll method has a larger deviation diameter difference, and therefore the size range of the product diameter that can be obtained by the two-roll method within the allowable deviation diameter difference is smaller than that of the four-roll method. By the way, the theoretical value of the size range where the difference in eccentricity is 0.5 mm or less is 1.7 mm in the two-roll method, 3.8 mm in the three-roll method, and 7 mm in the four-roll method.

Even if the size range of the product diameter in the 4-roll method is wide, the deviation in diameter becomes larger as the product diameter and the diameter of the arc of the caliber become more distant. There was a problem that the size range of about 1.5 mm was narrow even with the 4-roll method when trying to form a product of less than 0.1 mm. The present invention has been made in view of the above problems, and an object of the present invention is to provide a sizing rolling method in which the size range of the product diameter is wide only by adjusting the roll gap.

[0006]

In order to achieve the above-mentioned object, the sizing rolling method for a round steel bar according to the present invention is designed so that a material having a substantially circular cross section is rolled in four rolling directions.
In a sizing rolling method of rolling in series by two 4-roll rolling mills that are offset by 5 degrees, at least the second-pass 4-roll rolling mill is equipped with an arc having a diameter 1-14% smaller than the diameter of the material. By adjusting the roll spacing of the 4-roll rolling mill,
Round bar steel with different product diameter without changing rolls
Characterized by rolling .

[0007]

Material became almost circular cross section by the upstream rolling mill train than rolling mill for [action] sizing rolling, by being rolled by each other to two four-roll rolling mill shifted pressing direction 45 degrees, cross is shaped into a circle had close to Gayaya octagon. At this time, the product diameter is changed by adjusting the roll gap of the 4-roll rolling mill .

As in the prior art, when the diameter of the material is smaller than the diameter of the arc of the caliber of the roll, the deviation in diameter increases as the product diameter decreases. Further, as in the present invention, when the diameter of the material is larger than the diameter of the arc of the caliber of the roll, the difference in eccentricity is the smallest in that the product diameter is the same as the arc of the caliber. Diameter is on the large diameter side,
And, the smaller the diameter is, the larger the deviation in diameter becomes.

As described above, the size range that can be shaped is increased by having the allowable range of the eccentricity difference in the direction opposite to the conventional one. In the present invention , the limit of the value of the diameter of the arc of the roll caliber in the present invention is experimentally determined to be smaller than the diameter of the material.
When the diameter of the circular arc of the caliber is reduced by 14% or more, surface flaws due to biting occur and the product becomes defective. Therefore, the value is limited to the above value.

[0010]

An embodiment of the present invention will be described with reference to the drawings.
First, explaining the structure, the material cross-section ho by rolling mill train on the upstream side (not shown) is rolled substantially circular, to shape the predetermined product size, rolling machine is installed for the sizing rolling.

[0011] mill for the sizing rolling, as shown in Figure 1, the two four-roll rolling mill 1, 2 or we are composed, it and the product is shaped by two rolling paths Products
It The four-roll mill 1 for the first pass has two sets of calibers 1.
The facing directions of a and 1b are arranged in the vertical direction and the horizontal direction, respectively, and the rolling-down direction is directed to the vertical direction and the horizontal direction. The four-roll rolling mill 2 for the second pass is arranged so that the facing directions of the two sets of calibers 2a and 2b are each inclined by 45 degrees from the horizontal direction.

In the sizing rolling apparatus having the above-mentioned structure, the material 3 is shaped into a circle having a shape close to a quadrangle in the first pass, and is pressed in the first pass which is the maximum diameter portion after the first pass in the second pass. 8 is pressed down at the boundary of the surface
Is shaped into a circle had close to the square. At this time, as in the past,
When caliber 1a than the diameter of the material 3, 1b, 2a, the diameter of 2b large, the shaped product is polarized as the product diameter decreases diameter difference is large KuSei form.

When the diameter of the calibers 1a, 1b, 2a, 2b is smaller than the diameter of the raw material 3 as in the present invention, the shaped product becomes uneven as the product diameter becomes smaller.
Diameter difference is small, polarized in that the product diameter is equal to the diameter of the arc of the caliber diameter difference Ri minimum Do further, the product having a small diameter
The difference in eccentricity increases again as it becomes smaller . For example, material 3
2 has a diameter of 58 mm and an allowable deviation diameter difference of 0.5 mm, the sizable range is as shown in FIG.

According to the present invention, sizing rolling using a conventional caliber having the shape of an arc having a diameter of 58 mm, which is equal to the diameter of the material 3, and an arc having a diameter of 51 mm, which is 7 mm smaller than the diameter of the material, are performed according to the present invention. The relationship between the sizing rolling using the existing caliber and the difference in diameter and the possible product diameter was calculated.The one shown by the dotted line in the figure represents the conventional sizing rolling, and the one shown by the solid line is the Fig. 3 represents a sizing rolling according to the invention.

As can be seen from FIG . 2 , the allowable deviation diameter difference is set to 0.
If it is 5 mm, the size range of the product diameter that can be shaped only by adjusting the roll gap is about 7.75 mm in the conventional sizing rolling (A in FIG. 3), but about 14 mm in the sizing rolling according to the present invention ( It can be seen that the size range of the product diameter that can be shaped almost twice as in B) in FIG. 3 is expanded.

In particular, even in the case where a product having an eccentricity difference of 0.1 mm or less is required to be manufactured with extremely high precision, the size range that can be shaped only by adjusting the roll gap is
As can be seen from FIG. 2, it is about 1.25 mm in the prior art, whereas it is about 2.5 mm when the caliber according to the present invention is used, and the size range can be doubled.
As described above, it is possible not only to provide the tolerance range for the diameter deviation in the direction of the smaller product diameter, but also to allow the tolerance range for the diameter difference in the direction of the larger product diameter. Compared to,
The size range of the product diameter that can be adjusted only by adjusting the roll gap is 2
It can be expanded nearly twice.

[0017]

As described above, the method for sizing and rolling a round steel bar according to the present invention not only provides the allowable range of the diameter deviation in the direction in which the product diameter is small, but also the deviation in the direction in which the product diameter is large. It is possible to set the allowable range of the diameter difference , and the size range of the product diameter that can be adjusted only by adjusting the roll gap can be expanded almost twice as compared with the conventional method, reducing the roll change .
By doing so, it is possible to significantly reduce the operating time.

Especially, in the ultra-precision rolling (deviation difference of 0.1 mm or less) in which secondary processing steps such as cutting and drawing, which have been increasing in recent years, can be omitted , conventional sizing rolling is used.
Required frequent roll changes, but
In ging rolling, the size range that can be shaped can be expanded , and a significant roll change reduction effect can be obtained .

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an apparatus for sizing rolling according to the present invention.

FIG. 2 is a diagram showing a relationship between a deviation diameter difference and a shapeable product diameter.

FIG. 3 is a schematic configuration diagram showing a conventional apparatus for sizing rolling.

[Explanation of symbols]

 1, 2 and 4 roll rolling machine 1a, 1b, 2a, 2b Cariba

Front page continuation (72) Inventor Hidenori Kondo 1-chome, Mizushima Kawasaki-dori, Kurashiki City, Okayama Prefecture (without street number) Inside the Mizushima Steel Works, Kawasaki Steel Co., Ltd. (56) Reference JP-A-4-258302 (JP, A) Sho 63-43702 (JP, A) Japanese Patent Publication 3-6841 (JP, B2)

Claims (1)

(57) [Claims] 1. A sizing rolling method in which a material having a substantially circular cross section is rolled in series by two four-roll rolling mills whose rolling directions are shifted from each other by 45 degrees. A 4-roll rolling machine is used in which the roll bar of each roll of the rolling mill has a shape in which an arc having a diameter 1 to 14% smaller than the diameter of the material and an appropriate relief are arranged.
By adjusting the roll interval of the
A method for sizing and rolling a round steel bar, which comprises rolling a round steel bar having a reduced product diameter .