JPS623806A - Rolling method for clad steel - Google Patents

Abstract

PURPOSE:To maintain the same elongation percentage of both hard and soft materials by controlling temp. via rolls so that the hard material and soft material have the same deformation resistance in the rolling stage of a clad steel. CONSTITUTION:The clad steel I with the hard material 2 positioned on the upper side is fed into the spacing between work rolls 3 and 4. A small amt. of cooling water 8 is supplied to the rolls 3, 5 on the top side and a large amt. of cooling water 8 is supplied to the rolls 4, 6 on the bottom side in the stage of rolling. The rolls 3, 5 on the top side are thereby maintained at a high temp. and the rolls 4, 6 on the bottom side are maintained at a low temp. As a result, the temps. of the hard material 2 and soft material 1 of the clad steel I which are initially the same are made different so that the hard material 2 has the lower deformation resistance and the soft material 1 has the higher deformation resistance. The deformation in the clad steel I after rolling is thereby prevented.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a method for hot rolling clad steel.

Prior Art> A conventional rolling method for clad steel is shown in Fig. 4. In this method, a clad steel I consisting of a soft material 1 and a hard material 2 is rolled with rolls 10.11 of different diameters, and the amount of rolling strain of the soft material 1 and the hard material 2 is varied. Tsumashi,
When rolling at the same temperature, K,
Due to the difference in deformation resistance of both materials, when rolled with rolls of the same diameter, the curling L
and anti-shi C will occur. To prevent this, the diameter of the rolls is changed. In addition, in the figure, 5 is ・tsuku an roll.

As means for preventing the deformation of the clad steel I, in addition to the method of changing the diameter of the roll as described above, there is also a method of changing the circumferential speed of the roll.

<Problems to be solved by the invention> However, when applying the above method to an existing rolling mill,
Significant modification of the rolling mill is required, which raises the issue of equipment costs, and when applied to a newly installed rolling mill, additional equipment and controls are required compared to a normal rolling mill.

The present invention was made in view of the above situation K, and eliminates the deformation (bulging and warping) that occurs during hot rolling of clad steel in a normal rolling mill, without requiring capital investment or new installation, unlike conventional methods. The purpose of the present invention is to provide a new rolling method that can prevent this.

Means for Solving the Problems> The configuration of the present invention for achieving the above object is such that when hot rolling clad steel made of a hard material and a soft material, the deformation resistance of both materials is the same. It is characterized by rolling the material while controlling its temperature using rolls.

In the above method, the deformation resistance of the hard material and the soft material in clad steel -1 are made to match by controlling the temperature through the rolls, the rolling strain and load distribution are made the same, and thereby the elongation of both materials is This makes the rice the same and prevents it from being rolled up or stacked.

Embodiment FIG. 1 is an explanatory diagram of a rolling method according to an embodiment of the present invention.

(2) is clad steel, consisting of soft material 1 and hard material 2. 3 and 4 are upper and lower work rolls, between which the clad steel I is introduced and rolled. 5,6
is a backup roll that supports work rolls 3 and 4.

In this embodiment, as means for cooling the work rolls 3.4, a cooling water injection nozzle 7a is provided only on the exit side of the upper work roll 3, and a cooling water injection nozzle 7a is provided for the lower roll. Cooling water injection nozzles 7b and 7C are provided on both the inlet and outlet sides of the roll 4 and the backup roll 5.

Clad steel I is rolled into work roll 3 with hard material 2 on top.
．． Sent in between 4. During rolling, the dog side (upper side)
A small amount of cooling water 8 is supplied to the rolls 3 and 5, and a large amount of cooling water 8 is supplied to the rolls 4.6 on the entry side (lower side). This results in different roll temperatures between the top side and the bottom side. In other words, the top side roll 3,
5 is at a high temperature, and the rolls 4 and 6 on the entry side are at a low temperature.

As a result, the temperatures of hard material 2 and soft material 1 of clad steel I, which were at the same temperature at the beginning, become the same, and the deformation resistance of hard material 2 decreases by the amount of temperature increase, and conversely, the temperature of soft material I decreases. The deformation resistance increases accordingly. As shown in FIG. 5, a condition arises in which the deformation resistances of both are the same at temperatures A and B. In order to satisfy this condition, the temperature can be controlled by pouring cooling water onto the roll. According to this method, the clad steel I after rolling is free from deformation as shown in FIG.

In addition, in the present invention, the reason why the hard material side is placed upward and the cooling water is cooled is because if this was reversed, the cooling water on the top side would fall hot on the inlet side, making it difficult to control the roll temperature. .

<Effects of the Invention> According to the method for rolling clad steel according to the present invention, rolling can be easily carried out using an ordinary rolling mill without causing deformation of the clad steel, and the equipment can be easily rolled. It is also advantageous in terms of costs.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of the rolling method according to the present invention, FIG. 2 is a cross-sectional diagram of clad steel obtained by the method of the present invention,
Figure 3 (a3 (b) is a cross-sectional view of an example of a defect that occurs in shiflad steel by the conventional method, Figure 4 is an explanatory diagram showing the conventional cladding rolling method, and Figure 5 is a deformation resistance diagram of clad steel. In the drawing, ■ is clad steel, l is a soft material, 2 is a hard material, 3.4 is a work roll, 5.6 is a backup roll, and 7a, 7b, and 7c are cooling water injection nozzles.

Claims (1)

[Claims] A clad steel made of a hard material and a soft material, which is hot-rolled while controlling the temperature of both materials with rolls so that the deformation resistance of both materials is the same. rolling method.