JPH0576921A - Method for cooling high temperature rail - Google Patents

Abstract

PURPOSE:To provide a cooling method for a high temperature rail causing no bending at the tip part. CONSTITUTION:When rails 1, 10 at high temperature are cooled under the horizontal state on a cooling floor 3, the head sides of both tip parts of the rails 1, 10 charged into the cooling floor 3 are bent so that each of the head sides comes to the outside of the bend. As a result, such excellent results can be obtained that the necessity for press staightening of the rail is reduced drastically, the productivity is improved and the personnels can be rationalized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cooling a high temperature rail which does not bend when cooling a high temperature rail.

[0002]

2. Description of the Related Art A high temperature rail after hot rolling has an asymmetrical cross-sectional shape, and therefore has a problem that it is largely bent when cooled from a high temperature state to a normal temperature state in a cooling bed. In order to deal with this, for example, as shown in Japanese Patent Laid-Open No. 59-31824, the bottom of the rail is kept warm, and the temperature difference between the rail head and the bottom and the difference in cooling speed that occur during cooling are eliminated to prevent bending. There are things to prevent. In addition, as shown in Japanese Patent Laid-Open No. 63-11492, when cooling a high temperature rail that retains heat above the austenite region temperature that is heated for the purpose of finishing hot rolling or heat treatment, the rail top surface And its head side are cooled while injecting the refrigerant with an injection amount that satisfies the target strength of the material, and when the pearlite transformation amount of the rail head progresses from 40% to 60%, Some cooling is performed with a refrigerant injection amount of / 2 to 1/5.

[0003]

SUMMARY OF THE INVENTION
Neither of the methods described in JP-A-59-31824 and JP-A-63-11492 can manufacture a perfectly straight rail, and in particular, the straightness at the end is not sufficient. The bend at this end cannot be completely straightened by a roll straightening machine. That is, it is not possible to correct a bend generated in a length shorter than the distance between adjacent rolls. Therefore, there is no choice but to press-correct the bending that has occurred at both ends of the rail. The reduction in efficiency of the refining process caused by the press straightening of the end cannot be ignored, and is one of the factors that reduce the productivity.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for cooling a high temperature rail which does not bend and does not require press straightening.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a method for cooling a high-temperature rail in which bending does not occur without impairing various factors such as mechanical characteristics and productivity of the rail in the conventional rail manufacturing. In cooling a high temperature rail in a horizontal state on a cooling floor, both ends of the rail loaded on the cooling floor are bent so that the head side is outside the bending.

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 are a schematic perspective view and a plan view showing the concept of the present invention. In FIG. 1, 1
Is in a high temperature state such as the state where hot rolling is completed on the rail.
Reference numeral 2 denotes a transport roller, which vertically feeds the high-temperature rail 1 in the length direction. Reference numeral 3 denotes a cooling floor, which is connected to the conveying roller 2 so that the high temperature rail 1 longitudinally fed by the conveying roller 2 is sequentially fed horizontally in a state of being laid down.

The high temperature rail 1 which has been hot-rolled is vertically fed by the conveying roller 2 toward the inlet side of the cooling floor 3, and then horizontally fed to the inlet side of the cooling floor 3 in a state of being laid down. Charge. The high temperature rail 1 charged in the cooling floor 3 is bent at both ends so that the head side is outside the bend. The high temperature rail 1 whose both ends are bent so that the head side is outside the bend is straight when the bend returns to normal temperature during air cooling while laterally moving on the cooling floor 3.

That is, the high temperature rail 1 in the case where the head 11 is inserted to the entrance side of the cooling floor 3 and the bottom 12 is located on the exit side of the cooling floor 3 in a sideways state is shown in FIG. As shown, a stopper 4 installed so as to project to the desired position on the cooling floor 3 presses the bottom 12 side from the end at a desired position, and the head 11 side ends are moved back and forth to both sides of the cooling floor 3. The rail pressing device 5 movably installed pushes and bends the rail pressing device 5 toward the exit side of the cooling floor 3. At this time, the first hot rail 1
Presses a plurality of blooms, one bloom at a time, and then bends following the first one. The high-temperature rails 1 should press a plurality of one blooms at a time, and the rails loaded into the cooling floor 3 should be pressed sequentially. In addition, it is possible to freely select whether to press the desired number of pieces at once or one by one. The high-temperature rail 1 whose both ends are bent so that the head side is outside the bending is cooled (cooled) while being laterally fed on the cooling floor 3 toward the exit side.

[0009] Usually, a hot rail 1 loaded in the cooling floor.
Is cooled in a straight state, during cooling, the head 11 having a large mass is bent inside and the bottom 12 is bent outside. However, the high temperature rail 1 in which both ends are bent in advance so that the head side is outside the bending finally becomes the rail 10 at room temperature in which the ends are in a straight state. Therefore, it is not necessary to perform press straightening on the rail end portion in the straightening step, and the number of man-hours in the straightening step can be reduced.

[0010]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 3 is a side view showing the basic structure of an example of an apparatus used in the method of the present invention. Numeral 4 is a stopper which is installed on both sides of the cooling floor 3 so as to project or retract or detachably project upward. Reference numeral 5 is a rail pressing device installed on both sides of the cooling floor 3, and a claw 51 for pressing the rail 1 and the claw 5 are provided.
1 is a horizontal carriage 52 that holds the rail 1 so that it falls below the bearing surface of the rail 1, and the carriage 52
Carriage guide 53 in the form of a lateral groove that is supported so as to be able to move transversely in the direction perpendicular to the longitudinal direction of the carriage, a connecting handle 54 having one end connected to the carriage 52, and a connecting handle 5 having one end.
It has a swivel rod 55 which is rotatably connected to the other end of the swivel rod 4, the other end of which is supported by a fulcrum, and a hydraulic cylinder 56 which is connected to an intermediate portion of the swivel rod 55.

A case where the method of the present invention is carried out by the above apparatus will be described. The high-temperature rail 1, which has been cut or heated after hot rolling, is loaded on the entry side of the cooling floor 3 in a sideways state in which the head 11 is in front. At this time, the claw 51 is on standby near the entrance side of the cooling floor 3, and when the rail 1 passes, it is tumbled and sunk below the rail 1 bearing surface of the cooling floor 3. The high-temperature rails 1 of the number of fortunes (one bloom) that have passed the upper part of the claw 51 have stoppers whose bottom portions 12 side away from the end portions are projected on or removed from both sides of the cooling floor 3 or detachably project upward. Abut 4. Next, the high temperature rail 1 is bent by the carriage 5 which is operated by the hydraulic cylinders 56 of the rail pressing device 5 installed on both sides of the cooling floor 3 to press both ends from the head 11 side by a desired amount. After that, immerse or remove the stopper 4,
By operating a transfer (not shown), the above-mentioned rails are collectively advanced in the direction of arrow B. And claw 51
Moves to a standby position near the inlet side of the cooling floor 3. After that, the high-temperature rails 1 loaded into the cooling floor 3 are pressed one by one so as to bend following the first one, and the entire lengths thereof are sequentially brought into contact with each other.

The pressing of the rail 1 at a high temperature is caused by the bloom 1
It may be arranged such that a plurality of pieces each consisting of a plurality of pieces are collectively pressed, or that the pieces charged into the cooling floor 3 are sequentially pressed one by one. The high temperature rail 1 whose both ends are bent so that the head side is outside the bend is
Both ends are straight when cooled (cooled) while advancing sideways toward the exit side. During air cooling, the claws 51 are in a state in which both ends of the final rail 1 are pushed in. After that, the cooled rail 10 is carried out by an output side transfer (not shown) and sent to a straightening process.

Table 1 shows the test results using a R50N rail having a length of 25 m together with a conventional example. Since the temperature of the rail 1 when pressed by the claw 51 is about 760 ° C., the deformation resistance is small and the rail 1 can be easily bent. In case of R50N with a length of 25 m, the distance between the stopper 4 and the rail pressing device 5 is 300 mm.
And Table 1 shows the proportion of those requiring press straightening at the rail ends after roll straightening. As shown in Table 1, the present invention significantly reduces the press straightening incidence.

[0014]

[Table 1]

[0015]

According to the present invention, the degree of need for press straightening applied to the end of a cooled rail is significantly reduced, productivity is improved, and the rationalization of personnel is achieved. .

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing the concept of the present invention.

FIG. 2 is a schematic plan view showing the concept of the present invention.

FIG. 3 is a side view showing the basic structure of an example of an apparatus used in the method of the present invention.

[Explanation of symbols]

 1,10 Rail 2 Transport roller 3 Cooling floor 4 Stopper 5 Rail pressing device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mamoru Isobe 1-2 1-2 Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Yasuaki Nakatsuka 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Date Inside the Steel Pipe Co., Ltd. (72) Inventor Kiyomitsu Imaoka 1-2 1-2 Marunouchi, Chiyoda-ku, Tokyo Inside the Nippon Steel Pipe Co., Ltd.

Claims (1)

[Claims] 1. When cooling a high-temperature rail on a cooling floor in a sideways state, both ends of the rail loaded on the cooling floor are bent so that the head side is outside the bending. How to cool high temperature rails.