JPS62110806A - Preheating method for rolling roller - Google Patents

Abstract

PURPOSE:To preheat a rolling roller to an ideal heat crown by cross-providing a roller frame so that it can ascend and descend, on the upper part of a delay table of a hot rolling line, attaching the rolling roller to the frame and bringing the rolling roller into contact with a moving hot material which has been rolled roughly, from the upper part. CONSTITUTION:A rolling roller 6 to be preheated is attached to a roller frame 5, and at the time point when the tip of a hot material 2 which has come out of a rough rolling mill has passed through the roller frame 5, the roller frame 5 is made to descend so that the rolling roller 6 contacts the upper face of the hot material 2. In this case, a contact pressure of the rolling roller 6 is set to an extent that the rolling roller 6 is driven to rotate. Also, in order to prevent a collision against the rolling roller 6, the rolling roller 6 is brought into contact, after the tip of the hot material 2 has passed through the roller frame 5. Also, the reason why the contact to the hot material 2 is executed on a delay table between a rough rolling mill and a finish rolling mill is because a scale obstructs preheating before the rough rolling mill, and a shape and a plate thickness of the rolling material are varied after the finish rolling mill.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rolling row IVf used in hot rolling and a method for preheating the rolling row IVf before use.

[Conventional technology]

The hot rolling roll is heated during rolling by the sensible heat of the rolled material and the working heat of rolling. This heating is noticeable at the center of the roll, and the edges are not heated at the center. The rolling roll is designed to take into account the radial thermal expansion caused by this heating and to be given an appropriate roll crown in the heated state. It has a shape minus the crown.

Therefore, if the rolling roll/I/ff: is installed in a roll stand without preheating and rolling is performed, rolling is performed in a state where the roll crown is insufficient immediately after the start of rolling, and the roll is not rolled into an appropriate shape. For this reason, the rolling loaf m/'jH is preheated before it is assembled into the roll stand. Note that hot rolling consists of rough rolling and finishing rolling, and preheating is mainly performed with finishing rolls that ultimately determine the product shape.

[Problem that the invention seeks to solve]

Conventionally, preheating of rolling rolls during hot rolling has been carried out using a dedicated heating device using electricity or steam (see, for example, Japanese Patent Laid-Open No. 47-29258), which requires a large heating cost. Furthermore, when using these dedicated heating devices, it is naturally necessary to preheat off-line. It is also uneconomical that many low) VFs cannot be preheated at once.

Furthermore, when preheating the rolling rolls, it is not enough to simply raise the roll temperature;
/It is necessary to preheat according to the temperature distribution.

That is, it is necessary to provide a preheating temperature distribution such that the center of the roll is at a high temperature and both ends are at a lower temperature than the center. Although conventional dedicated heating devices have been designed to meet these demands, the device configuration has become more complex and the fabrication methods have become more complicated.

The present invention provides a method for preheating a mill roll that solves all of these problems.

[Means for solving problems]

The method for preheating a rolling roll of the present invention includes installing a roll mount that can be raised and lowered over a delay table between a rough rolling mill and a finishing rolling mill of a hot rolling line, and placing a roll mount on the roll mount that is to be preheated. The rolling row (I) is attached and the rolling row (V) is brought into contact with the roughly rolled hot material moving on the delay table from above to preheat it.

[Effect]

Thickness: 227ya, length: 8m, weight: 15t /M7
When hot rolling to a thickness of 8.0 mm, the passing time of the material (rough bar) through the delay table is about 9 seconds.

During this time, when the hot material moving on the delay table is brought into contact with the rolling roll) Vf liquid, the rolling roll will have rolling roll/L
The amount of heat for total preheating is applied and the low) V temperature rises to about 80° C. after the lO wood interest has passed, for example.

According to this preheating method, not only is a heat source for preheating unnecessary, but also preheating can be performed within the hot rolling line, that is, online! , multiple rolling rows/V'
It is also possible to preheat to xM.

Furthermore, bringing the rolling roll into contact with the hot material means that the rolling roll is preheated under the same conditions as during rolling. Therefore, the roll temperature distribution obtained by this preheating will be in an ideal distribution state as long as the absolute heating temperature is controlled.

Since the surface layer of the rolling roll can be preheated and the rolling roll (VF) liquid can be brought into contact with a plurality of materials, the amount of heat supplied to the rolling roll will not be insufficient. Therefore, the absolute heating temperature of the roll can be easily adjusted by the cumulative contact time between the roll and the hot material or the cooling time after preheating.

A preferable preheating time is 60 to 180 seconds in terms of cumulative contact time; if the preheating time is less than 60 seconds, a low crown will not be applied sufficiently. On the other hand, if it exceeds 180 seconds, the heat crown will become too large, and it will also have a negative effect on the roll chock.

Figure 2 shows the change over time in the surface temperature of a part of the roll center (A in the same figure) and the change in the heat crown over time (Open in the same figure) when the uninvented preheating method was carried out under the conditions of the example described later. . Under these conditions, the surface temperature is 80°0, the heat crown is 25
In order to obtain 0μ, a cumulative preheating time of 90 seconds is required, and if the average passing time of one material is 9 seconds, then 10
It can be brought into contact with wooden materials.

Since the rolling roll has a large heat capacity, the temperature drop after preheating is small even if the surface layer is preheated, and there is virtually no temperature change for about 80 minutes, and the roll can be replaced during this time.

〔Example〕

FIG. 1 is a side view of an example of a device suitable for carrying out the inventive preheating method. In the figure, (1) shows the delay tape /L/ of the hot rolling line, (2r shows the hot material after rough rolling that moves on the delay table. Below both sides of the delay table 11 there are frames ( 3), and a roll mount (5) is provided to this via an elevating mechanism (4) so as to straddle the delay tape /L/(21). low/l
/(Place the roll chock (7) of 61 into the upper mold (8) and the lower mold (
9) and is fixed with bolt α0 (10). Further, this roll mount (5) has a structure in which a plurality of receiving portions for roll chocks (7) are provided in the material movement direction so that a plurality of rolling rows /L/(61) can be preheated at once.

0]) is a hydraulic cylinder that is the power source for raising and lowering the roll frame (5), and 0202 is the frame (3) and roll frame (5).
This is a counter-type pedestal height detector installed on the material entry side.

To carry out the inventive preheating method using the above device,
First, before starting hot rolling, the rolling roll /l/(61) to be preheated is attached to the roll frame (5).

When hot rolling starts, the hot material (2
) before the tip reaches the roll stand (5),
Predict its arrival. This includes, for example, hot materials <21
From the time when the detector detects the passage of the material, the movement of the leading edge of the material can be tracked by capturing the rotation of the roller table with the Pannuzi generator. Then, when the leading edge of the material has finished passing through the roll pedestal (5), the roll pedestal (5) is completely lowered so that the rolling roll /l/ (61) comes into contact with the upper surface of the hot material (2).

The contact pressure of the rolling row/L'(6) against the hot material (2+) may be large enough to cause the rolling row/L/(61 to rotate as the hot material (2) advances. Excessive contact pressure is undesirable because it deforms the hot material (6) and increases the force applied to the 't* equipment, but if it is a slight material deformation, it is not a particular problem as it will be corrected in the finishing mill in the subsequent stage. .The preferable contact pressure is specifically 10Ton to 50Ton.
It is Ton.

The lowering position of the roll frame (5) is determined by taking into account the thickness of the hot material (2) and the above-mentioned contact pressure. What should be considered at this time is not to make a large change in the thickness of the material, and to ensure uniform contact with the roll in the width direction.

After the tip of the hot material (2) has passed the roll stand (5), the hot material (rolling roll to 21) v (61e
The tip of the hot material (2) is brought into contact with the rolling roll/l.
/(This is to prevent collision with 61.

When the hot material (2) has completely passed through the roll pedestal (5), the hydraulic cylinder 01) is fully activated to raise the roll pedestal (5) to its original initial height. Roll roll (6
) is heated more than necessary, the roll pedestal (5) may be fully raised before the hot material (2) has passed past the roll pedestal (5). After the roll mount (5) is fully raised, move the rolling roll 1v (6Hr) roll mount (5) as appropriate.
5) Remove from.

In the preheating method of the present invention, the contact between the hot material (21 and the rolling roll/l/(6) is carried out on the delay table between the rough rolling mill and the finishing rolling mill before the rough rolling mill. In this case, there is a risk that the scale attached to the material may obstruct the preheating of the rolling roll (6), and after the finishing mill, the shape and thickness of the rolled material may change, which may adversely affect the final product. .

In the ffC example, setting the rolling row/L/(6) on the roll stand (5) with the roll chock (7) fully attached is to install the rolling row (6) on the ffi roll stand after preheating. This is because it is easy, and since a bearing mechanism is not required for the roll frame (5), the structure of the frame can be significantly simplified.

In the hot rolling line, the specifications are shown in Table 1 and the low μ arrangement is shown in Figure 4, the dimensions are diameter 780 and body length 21007.
A rolling mill having a length of 1 m and a weight of about 10 tons was preheated by an uninvented method. The preheating conditions are shown in Table 2.

Table 1 Table 2 The roll crown immediately after preheating and the target roll crown are shown in FIG. 8 by solid lines and broken lines, respectively.

As is clear from the figure, in the method of the present invention, an almost ideal heat crown can be obtained only by contact heating of the hot material.

〔Effect of the invention〕

As is clear from the above description, since the preheating method of the present invention utilizes the sensible heat of the rolled material as heating energy, there is no need for an energy converter, and the effect of sensible heat recovery and energy saving is significant.

! Since multiple rolling rows can be preheated at once, the efficiency of the preheating itself is also high. Furthermore, since preheating is performed using actual hot rolling, preheating is performed under conditions extremely close to those of actual rolling, and a nearly ideal heat crown can be imparted to the rolling roll without the use of complicated equipment or methods. can.

[Brief explanation of drawings]

FIG. 1 is a side view showing an example of an apparatus suitable for carrying out the method of the present invention, and FIGS. 2(a) and 2(b) illustrate the roll surface temperature and heat crown over time, illustrating the inventive preheating effect. Similarly, FIG. 8 is a temperature distribution diagram in the axial direction of the rolling rolls, and FIG. 4 is a diagram showing the roll arrangement of the hot rolling line used in the example. In the figure, 1: delay table, 2: hot material after rough rolling, 5: roll stand, 6: rolling roll.

Claims (1)

[Claims] (1) A roll pedestal is installed above the day table between the rough rolling mill and the finishing rolling mill of the hot rolling line so as to be able to rise and fall, and the rolling roll to be preheated is attached to the roll pedestal. 1. A method for preheating a rolling roll, comprising: bringing the rolling roll into contact with a roughly rolled hot material moving on a rolling table from above to preheat the material.