JP3280254B2 - Rolling roll of continuous hot finishing mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a rolling roll of a continuous hot finishing mill.

[0002]

2. Description of the Related Art It is known that a convex crown is formed on a work roll of a rolling mill to make the shape in the width direction of a steel strip uniform. Further, by forming a convex crown on the backup roll, without impairing the shape of the rolled steel strip, to a roll having a large crown control ability,
It is disclosed in Japanese Patent Publication No. 2-49163. Furthermore,
JP-A-5-23705 discloses that a crown of a backup roll is formed in a trapezoidal shape to form a concave crown in which a straight portion is formed in a center portion of a roll width of a work roll crown.

[0003]

As described above, in the former rolling roll, the crown control ability of the rolling mill can be increased, and the above-mentioned crown-shaped backup roll is disposed on the front stand to reduce the rolling. It is to prevent shape defects such as middle elongation and ear elongation of the steel strip. In the latter rolling roll, no contact load is generated from the backup roll in a portion where the steel strip does not exist in the case of narrow width steel strip rolling, and in the case of wide width steel strip rolling, a concave crown at the end of the work roll is used. The generation of a negative strip crown can be prevented, and the defective shape of the rolled steel strip can be prevented. In such a roll, the stress between the roll and the backup roll cannot be equalized in the roll width direction during the thermal crown of the work roll (when the crown is formed) after the start of the rolling. Poor shape (e.g., medium elongation) of the rolled steel strip may occur, deteriorating the quality and leading to a stoppage of the rolling equipment due to the drawing breakage of the steel strip. Further, recently, there is a tendency to use a work roll (generally referred to as a high-speed roll) made of a material made of high wear resistant steel or high carbon steel (high wear resistant steel) containing V, W, Cr, Mo or the like. In a work roll made of such high wear-resistant steel, the wear progresses slowly and is durable, which is excellent in itself. The amount of reduction at the center in the width direction of the steel strip is larger than that at both ends, so that the middle elongation state rolling continues for a long time. Therefore, the quality deterioration of the rolled steel strip increases, and the yield decreases. Further, there is a problem that a drawing break easily occurs due to the middle elongation of the rolled steel strip, and the productivity decreases due to a decrease in the operation rate due to the stoppage of the rolling equipment. The method of the present invention has been made to advantageously solve such a problem, and a concave crown similar to a thermal crown of a work roll is formed on a backup roll, and a work roll and a steel strip are formed in a width direction of the steel strip. An object of the present invention is to solve the above-mentioned problem by relaxing the deviation of the contact stress.

[0004]

A feature of the method of the present invention is that a concave crown similar to a convex thermal crown of a work roll is formed on a backup roll, and the concave crown is connected to the concave crown and both ends in the width direction of the backup roll. A rolling roll of a continuous hot finish rolling mill characterized in that a surface pressure-optimized shape is formed in a portion.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a rolling roll according to the present invention forms a convex crown 2 on a work roll 1 and forms a concave crown 3 similar to a thermal crown formed by rolling on a backup roll 4. . In addition, at the both ends of the backup roll 4 in the width direction, the surface pressure optimized shape 5 is formed. Such a rolling roll 6 is arranged symmetrically above and below a rolling steel strip 7 threading position to roll the steel strip. Thus, the height of the concave crown 3 of the backup rolls 4 and 4a is equal to the convex thermal crown 2 of the work rolls 1 and 1a.
2a, the work roll 1
Although it is determined by the convex thermal crown amount of 1a, a hot finish rolling mill generally used with a thermal crown amount of 100 to 500 μm can surely perform good rolling. The concave crowns 3 and 3a of the backup rolls 4 and 4a are connected to connect the backup rolls 4, 4a.
The shape 3 of the crowns 3 and 3a formed at both ends in the width direction 4a is determined based on the width of the passing plate of various rolled steel strip width sizes. The function of the surface pressure optimizing shape 5 between the crowns 3 and 3a is to equalize the surface pressure between the work rolls 1 and 1a and the backup rolls 4 and 4a in the width direction so that the work rolls 1 and 1a are The purpose of the present invention is to alleviate the deviation of the contact stress in the width direction with the rolled steel strip 7 and prevent disturbance (deformation) in the shape of the strip steel strip.

An example of determining the crown 3, 3a surface pressure-optimized shape 5 by a mathematical formula will be described. In FIG. 2, F = L / 2− (B / 2 + α) = 1727 / 2− (rolled steel strip width / 2 + 70), where F: crown width setting shape (mm), α: length of the work roll convex thermal crown sudden change area Sa [L: 1727
(Mm)]

[0007] Such rolling rolls are arranged on each rolling stand of a hot finishing mill, and the rolling amount of each rolling stand is formed to be the same as that of the rolling stand. The stress at the center in the width direction between the backup rolls 4 and 4a and the work rolls 1 and 1a during the formation of the convex thermal crown of the work rolls 1 and 1a at the start of rolling is reduced, and the shape of the rolled steel strip is reduced. It is intended to improve the quality by improving the quality and to avoid the drawing fracture of the rolled steel strip. Further, in the work rolls 1 and 1a made of high wear-resistant steel, it is possible to surely prevent the shape defect of the rolled steel strip after forming the convex thermal crown and to improve the quality.

[0008]

Next, operation examples of the present invention will be described together with comparative examples.

[Table 1]

[0009]

[Table 2] (continuation of Table 1)

Note 1: The work roll material is R1: V,
A commonly used high wear-resistant steel roll (work roll diameter 700 mm) made of an alloy containing W and Co, or R
2: Highly wear-resistant steel rolls (commonly known as Ni-Gr rolls, work roll diameter 700 mm) mainly composed of Fe, C, and Ni, and backup rolls are generally used cast iron rolls (diameter 1500 mm). . Note 2: In Examples 2 to 4 and Comparative Examples 2 to 4, in the seven finishing stands of F1 (incoming rolling stand) to F7 (outgoing rolling stand) of the hot finishing rolling mill, the above specifications are applied to each rolling stand. The work roll and the backup roll were disposed and rolled. Example 1 and Comparative Example 1 correspond to four of F1 to F4.
In the rolling stand, the work roll R1 is moved to F5 to F7.
In the three rolling stands, the work roll R2 was disposed, and the backup roll was disposed in each of the rolling stands F1 to F7 to perform rolling. Example 5 and Comparative Example 5
The work roll R1 was provided on the six rolling stands F1 to F6, the work roll R2 was provided on one rolling stand F7, and the backup roll was provided on each of the rolling stands F1 to F7. Note 3: Crown amount of Example 1 and Comparative Example 1 -50 μm
Indicates the concave crown depth. Others indicate convex crown height. Note 4: The steel strip rolling temperature is the F1 (entry rolling stand) temperature of the hot finishing mill. Note 5: Crown height of backup roll, A is convex crown height of 1000 μm. B is a flat shape. Note 6: The shape defect rate is a shape defect rate due to medium elongation, and the shape defect rate of 10,000 km rolling is shown in each case. Note 7: The number of rolled steel strip breaks is the number of rolled steel strip breaks when rolling the strip pressure extension of Note 5.

[0011]

According to the present invention, it is possible to improve the rolling shape of the hot-finish rolled steel strip, thereby improving the quality and the yield. Further, it is possible to remarkably reduce steel strip breakage during rolling due to defective shape of the rolled steel strip, and to obtain excellent effects such as avoiding productivity due to stoppage of operation of the rolling mill.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a side view showing a shape of a backup roll. DESCRIPTION OF SYMBOLS 1 Work roll 1a Work roll 2 Convex crown 2a Convex crown 3 Concave crown 3a Concave crown 4 Backup roll 4a Backup roll 5 Appropriate surface pressure shape 6 Rolling roll 7 Rolled steel strip

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tadaomi Sato 5-3 Tokai-cho, Tokai-shi, Aichi Prefecture Nippon Steel Corporation Nagoya Works (56) References JP-A-5-23705 (JP, A) JP-A-5-228510 (JP, A) JP-A-57-72704 (JP, A) JP-A-5-285503 (JP, A) JP-A-62-296902 (JP, A) JP-A-57-109524 (JP-A-57-109524) JP, A) JP-A-63-112005 (JP, A) JP-A-9-125159 (JP, A) JP-A-61-266107 (JP, A) JP-A-59-94701 (JP, U) Hei 2-49163 (JP, B2) Jikken 46-13534 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21B 27/02 B21B 29/00 B21B 27/00

Claims (2)

(57) [Claims] 1. A backup roll having a concave crown similar to a convex thermal crown of a work roll, and a surface pressure-optimized shape formed at both ends in a width direction of the backup roll by being connected to the concave crown. Rolls of a continuous hot finishing mill. 2. The rolling roll of a continuous hot finishing mill according to claim 1, wherein the surface pressure-optimized shape is formed in a horizontal linear shape.