JP2002160001A - Direct-feed rolling method and mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a direct-feed rolling method and mill wherein a cast metal piece can be bitten by the mill at or above a temperature at which it is possible to bite the cast metal piece even without a heat insulating means, and wherein uneven cooling during conveyance can be alleviated. SOLUTION: In the process of conveyance the cast metal piece 1 is turned by a turning means, for example so that the rear end of the cast metal piece 1 during casting is made the front end for rolling whereby a biting temperature is secured. Uneven cooling is alleviated by conveying a waiting cast metal piece 11 while being partially or totally kept apart up from conveying rolls by a pushing-up means and/or by conveying a cast metal piece 12 while being tilted and turned sideward by a tilting/turning means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct rolling method and apparatus, and more particularly, to a direct rolling method and apparatus for conveying and rolling a slab immediately after continuous casting.

[0002]

2. Description of the Related Art In direct rolling, a cast slab is directly sent to a rolling mill as it is at a high temperature and hot-rolled, so that the slab is usually reheated by a heating furnace before rolling. Is omitted to save energy. But,
During the direct feeding of the cast slab to the rolling mill, the heat of the slab is gradually lost, and the slab end temperature may be lower than the temperature at which the rolling mill can bite. If rolling is performed in such a case, there is a high risk of causing defects such as poor biting and cracking. Therefore, in order to keep the slab end temperature higher than the temperature at which the rolling mill can bite, various methods of keeping the slab end at the time of direct feeding have been conventionally proposed (for example, Japanese Patent Application Laid-Open No. Sho 56-95407).
JP-A-58-163505, JP-A-57-91815 and the like.

[0003]

However, in the method of keeping the slab warm, it is necessary to always provide a heat-retaining means (cover or heat-insulating material), which is costly. It is necessary to provide a dedicated facility around the transfer line, and it may be difficult to realize the facility due to restrictions such as installation space, facility cost, and facility maintenance load. In addition, the slab that has exited the casting machine is directly fed by the transport roller, but so-called partial cooling in which the portion in contact with the transport roller preferentially cools occurs, and the deformation resistance of the partial cooling portion is higher than that of other portions. When rolling is performed, shape defects such as warpage and bending occur during rolling, and it becomes easy to hinder the threading or threading.

[0004] Therefore, the present invention provides a direct-feed rolling method and apparatus that can cast a slab into a rolling mill at a temperature equal to or higher than the temperature at which it can be bitten without a heat retaining means and can reduce uneven cooling during conveyance. The purpose is to:

[0005]

The present invention which has achieved the above objects is as follows. (1) A direct-feed rolling method for conveying and rolling a slab immediately after casting, wherein rolling is started from a casting tail end of the slab. (2) A direct-transfer rolling method in which a slab is transported and rolled immediately after casting, wherein a part of or a part of a slab waiting in the middle of transportation is separated from a transport roller.

(3) A direct feed rolling method in which a slab is conveyed and rolled immediately after casting, wherein the slab is tilted around a traveling direction during the conveyance to change a contact point with a conveyance roller. Direct rolling method. (4) A direct-feed rolling apparatus for conveying and rolling a slab immediately after casting, the slab turning means for rotating the slab on a conveying roller.

(5) A direct feed rolling apparatus for conveying and rolling a slab immediately after casting, comprising a slab push-up means for pushing up at least one portion of the slab on a conveying roller. (6) A direct feed rolling apparatus for conveying and rolling a slab immediately after casting, comprising a slab tilting means for tilting the slab on a transport roller around a traveling direction.

[0008] Here, the direct rolling mill according to the present invention is:
A casting machine (preferably a continuous casting machine) for casting a slab, a rolling mill for rolling a slab cast by the casting machine, and a slab coming out of the casting machine sent directly to the rolling mill by a transport roller. And a transfer device that performs the transfer.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Conventionally, it has not been considered which of the casting tip and the casting tail end is used as the rolling tip, whereas in the present invention (1), the casting tail end is set at the rolling tip. Specified. The slab temperature immediately after casting is the lowest at the casting tip and the highest at the casting tail end. This tendency is the same even after conveyance (rolling mill entry side). For this reason, conventionally, when the rolling tip = casting tip, under the transporting conditions such that the casting tail end temperature ≧ the biting possible temperature> the casting tip temperature at the rolling mill entry side, the rolling tip temperature <the biting possible. The temperature was so high that rolling was difficult.
However, in the present invention (1), since the rolling tip always equals the casting tail end, the rolling tip temperature ≧ the biteable temperature is satisfied even under the above-described transport conditions, and the rolling can be easily performed.

In many cases, it is necessary to change the direction of the slab in order to set the tail end of the casting to the tip of the rolling. Therefore, the direct-feed rolling apparatus uses the casting according to the present invention (4) as shown in FIG. The one having one-side turning means is preferable. In this example, the transport direction is orthogonal to the rolling direction, and the rolling mill 6 is on the right side of the transport path. The slab (billet) 1 that has exited the continuous casting machine is conveyed from the lower side of the figure by the conveying roller 3 with the casting tail end A as the conveying tail end. Then, the tip of the cast slab 1 is received by the stopper 2, and the tip of the slab 1 is rotated 90 ° counterclockwise in the drawing by pushing the caster 1 sideward with the stopper 2 as a center of rotation. I try to put it on 4. As a result, the slab 1 'on the transport roller 4 has the casting tail end A' on the high temperature side at the head, and bites into the rolling mill 6 from the high temperature side. Note that the turning angle is not limited to 90 ° in this example, but may be arbitrary (for example, 180 °) depending on the layout of the line.
° etc.).

Next, in the present invention (2), the cast slab waiting in the middle of the transportation is partly or entirely separated from the transportation roller. According to this, the heat loss due to the contact with the transport roller is reduced, and it becomes easy to achieve the slab end temperature ≧ the bitable temperature, and the uneven cooling can be reduced. This method and the method of the present invention (3) to be described later are particularly effective when implemented immediately after the start of operation, such as immediately after start-up from a periodic repair in which the temperature of the transport roller is low.

This method can be carried out, for example, by the slab pushing-up means according to the present invention (5) as shown in FIG. In this example, a push-up mechanism constituted by a tilting arm 8 driven and lowered by an air cylinder 10 is disposed below a slab end stop position. When the arm 8 is raised, the tip of the tilt arm 8 pushes up one end of the slab to incline the slab 11, so that the slab 11 can be partially separated from the transport roller 9 easily. Also, to separate the entire slab from the transport roll,
For example, another push-up mechanism as described above may be provided below the stop position of the other end of the slab, and push up each one of the two ends of the slab. The lifting mechanism is not limited to this example. For example, the lifting mechanism may be configured so that the arm moves vertically.

Next, in the present invention (3), the slab is tilted around the traveling direction during the conveyance to change the contact position with the conveyance roller. According to this, since the heat removal due to the contact between the slab and the transport roll is reduced, the uneven cooling can be reduced. This method can be implemented by, for example, the slab tilting means according to the present invention (6) as shown in FIG. In this example, in a suitable section of the transport line, the transport rollers are arranged as one-side tapered rollers 13 having a larger taper angle toward the downstream side in the traveling direction (the farther side in the direction perpendicular to the paper surface). Alternatively, an air cylinder 14 for pushing up the slab may be provided on the exit side of the section. Reference numeral 15 denotes a guide plate. The slab 12 passing through this section gradually tilts laterally because the bottom surface is gradually inclined by the one taper surface whose taper angle gradually increases in the traveling direction. Alternatively, it may be tilted 90 ° by further pushing up with the air cylinder 14. If such a slab tilting means is appropriately provided on the transport line, only a specific side surface of the slab comes into contact with the transport rolls, so that heat is intensively removed, and troubles such as warpage on the passing plate occur. Can be prevented. In addition, the slab tilting means,
The invention is not limited to this example, and may be configured with, for example, only an air cylinder for pushing up.

[0014]

[Example 1] (Example 1) In a billet direct-feed rolling equipment in which the shortest possible slab transport time from the end of the continuous casting machine to the rolling mill = 50 seconds, and the biting temperature of the rolling mill = 900 ° C, the conventional The casting tip was the rolling tip, but the billet of 120 mm square x 4.5 m was the temperature from tip to tail end immediately after casting = 930 to 980.
° C, the average cooling rate during transport = 40 ° C / min, the bite temperature was lower than the bitable temperature, and it was difficult to roll without keeping the temperature during the transport. Therefore, according to the present invention, the billet is turned as shown in FIG. 1 and the casting tail end on the high temperature side is used as the rolling tip, so that the rolling can be easily performed without keeping the temperature.

(Example 2) In Example 1, uneven cooling in which the bottom of the billet at the time of standby was lower by about 30 ° C than the other part during the transportation occurred during the conveyance, and a defective rolling shape sometimes occurred. Therefore, according to the present invention, the cast slab was pushed up and inclined as shown in FIG. 2 to eliminate the uneven cooling. (Example 3) In Example 1, uneven cooling in which the bottom was lower by about 30 ° C than in other parts of the billet from the start of the operation to the first few billets occurred, and a defective rolling shape sometimes occurred. Therefore, according to the present invention, the billet was conveyed while being tilted to the side as shown in FIG. 3, thereby eliminating the uneven cooling.

[0016]

According to the present invention, a slab directly fed without a heat retaining means can be bitten into a rolling mill at a temperature higher than a temperature at which the slab can be bitten. Thus, it is possible to avoid the trouble on the passing plate due to the above-mentioned effects.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a slab turning means.

FIG. 2 is a side view showing an example of a slab pushing-up means.

FIG. 3 is a side view showing an example of a slab tilting means.

[Explanation of symbols]

 1, 1 ', 11, 12 cast slab (billet) 2 stopper 3, 4, 9 transport roller (table roller) 5 kicker 6 rolling mill 8 tilting arm 10, 14 air cylinder 13 roller with one taper 15 guide plate

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor, Yoshisuke Kita 1-chome, Mizushima-Kawasaki-dori, Kurashiki-shi, Okayama Pref. (Inside Mizushima Works, Kawasaki Steel Co., Ltd.) 1-5-1, Tohoku Steel Co., Ltd. (72) Inventor Takeaki Shimizu 1-5-1, Minato, Miyagino-ku, Sendai, Miyagi Prefecture F-term in Tohoku Steel Co., Ltd. 4E002 AA04 AB06 BA03 BD02 CB05

Claims (6)

[Claims] 1. A direct rolling method for conveying and rolling a slab immediately after casting, wherein the rolling is started from a casting tail end of the slab. 2. A direct-feed rolling method in which a slab is transported and rolled immediately after casting, wherein a part of or a part of a slab that is on standby during transportation is separated from a transport roller. 3. A direct feed rolling method in which a slab is conveyed and rolled immediately after casting, wherein the slab is tilted around a traveling direction in the course of conveyance to change a contact point with a conveyance roller. Direct rolling method. 4. A direct feed rolling apparatus for conveying and rolling a slab immediately after casting, comprising a slab turning means for turning the slab on a conveying roller. 5. A direct feed rolling apparatus for conveying and rolling a slab immediately after casting, wherein at least one of the slabs on a conveying roller is provided.
A direct-feed rolling device comprising a slab pushing-up means for pushing up a portion. 6. A direct feed rolling apparatus for conveying and rolling a slab immediately after casting, comprising a slab tilting means for tilting a slab on a transport roller in a traveling direction. .