JPH05295444A - Device for heat-treating rail - Google Patents

Abstract

PURPOSE:To enable an efficient heat treatment shortening non-cooling loss time. CONSTITUTION:This device is constituted of a cooling device 1 for simultaneously cooling the whole length of a rail after hot-rolling, a rail carry-in device 2a and a rail carry-out device 2b arranged in parallel to the cooling device 1 at both sides of the cooling device 1 as the devices for carrying the rail in a drawing direction, a rotation and carry-in device 3a for carrying the rail while rotating from the rail carry-in device 2a into the cooling device 1, a rotation and carry-out device 3b for carrying the rail while rotating from the cooling device 1 to the rail carry-out device 2b. During cooling of the rail in the cooling device 1, the following cooling rail is waited at the charging position 2a to the cooling device and the carry-out of the already cooled rail from the cooling device 1 and the carry-in of the following cooling rail into the cooling device 1 are simultaneously performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of a rail heat treatment apparatus.

[0002]

2. Description of the Related Art In general, a hot rolled rail for domestic use can secure 3 or 4 cuts of a 25 m fixed length rail from one hot rolled material. Hot-rolled material with such a rail is usually 20 to 1 hour.
25 pieces, that is, a pitch of 2 minutes 30 seconds to 3 minutes is manufactured.
On the other hand, the heat-rolled rail is subjected to heat treatment (cooling treatment), but if the desired structure and hardness are to be obtained in this heat treatment, the temperature between 750 ° C and 500 ° C is 1-3 ° C / sec.
It is necessary to cool at a cooling rate of, for this reason, cooling requires at least 90 seconds, and stable cooling requires about 150 seconds. In addition to this, it is required for loading and unloading rails on the cooling line, turning the rails from the rolling posture (sideways posture) to the cooling posture (upright posture), and setting the relative position between the rails and the cooling header. There is also non-cooling loss time. Therefore, if it is attempted to cool the hot-rolled material only with the cooling device for one material, the heat treatment does not catch up with the supply of the hot-rolled material, and the hot-rolling efficiency is inevitably reduced.

[0003]

As a heat treatment apparatus for quenching a rail immediately after hot rolling, Japanese Patent Publication No. 13012/1990 has been proposed.
The rail heat treatment apparatus described in Japanese Patent Publication is known. This device has a stacking transfer device such as a chain transfer that moves in a direction perpendicular to the direction in which the rail extends, and a plurality of cooling zones corresponding to the rail length are arranged in parallel in the middle of this transfer device. A plurality of rails in an upright state are conveyed by a stacking conveyance device in a direction perpendicular to the direction in which the rails are stretched, and a plurality of rails in the middle of this conveyance are stopped and restrained / positioned at the cooling zone position, and the head of each rail and The foot is cooled by injecting a cooling gas from the injection header.

However, even with this apparatus, there is too much time loss to carry the rails for several rows into the apparatus, and the above-mentioned drastic reduction of the hot rolling efficiency cannot be avoided. The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a rail heat treatment apparatus capable of minimizing a non-cooling required time.

[0005]

In order to achieve such an object, the rail heat treatment apparatus of the present invention is a cooling apparatus capable of simultaneously cooling the entire length of the rail after hot rolling, and an apparatus for transporting the rail in its extending direction. A rail carry-in device and a rail carry-out device which are arranged on both sides of the cooling device in parallel with the cooling device, a turning-in / carrying-in device for carrying in the rail while turning it from the rail carry-in device to the cooling device, and cooling the rail. It is characterized in that it comprises a turning-out device which carries out the device while turning it out to a rail carrying-out device.

[0006]

The operation of the device of the present invention will be described with reference to FIG. The hot-rolled rail A ₁ is conveyed in the extending direction by the rail carry-in device 2a, and is carried laterally to the side of the cooling device 1 as shown by the solid line in FIG. Then the rail A ₁
Is carried into the cooling device 1 while being turned to an upright state by the turning / carrying-in device 3a as shown by the phantom line in FIG. The rail A ₁ carried into the cooling device 1 in an upright state is
As shown in FIG. 1 (b), the foot portion is restrained by the rail foot portion supporting / constraining device 4, and the refrigerant injection header 5 is set (the refrigerant jet header for cooling the rail head top portion and the rail head side portion). And is cooled for about 90 seconds to 150 seconds by the refrigerant injection header 5 and the refrigerant injection header 5'for cooling the sole of the rail.

By the time the cooling of the rail A ₁ is completed, the next cooling rail A ₂ is carried in by the rail loading device 2a as shown in FIG. 1 (c) and stands by at the side of the cooling device 1. ing. After cooling the rail A ₁ , as shown in FIG. 1D, the refrigerant injection header 5 is removed (the refrigerant head for cooling the top of the rail and the cooling of the side for cooling the rail head are lifted), and the foot of the rail is also lifted. The restraint by the supporting / constraining device 4 is released, and thereafter, the rail A ₁ is unloaded to the rail unloading device 2b side while being turned sideways by the tumbling / unloading device 3b, and at the same time, on the rail loading device 2a. The rail A ₂ which has been on standby is carried into the cooling device 4 while being turned from the sideways state to the upright state by the turning and loading device 3a, and the rail A ₂ is cooled. Through the above cycle, the cooling of the rail A and its loading / unloading are sequentially performed.

FIG. 10 shows the time cycle of rail cooling by the device of the present invention, which is a comparative device, that is, a transport device and a turning / transport device on one side for loading and unloading the rail with respect to the cooling device (in the example of FIG. 1, This is shown in comparison with a device which is performed only by the rail carry-in device 2a and the turning / carrying-in device 3a). According to this, the cooling pitch of the comparative example device is tp, and the cooling pitch of the present invention device is t'p. In that case, tp = 2 × (tm + ts) + tc in the device of the comparative example, whereas t′p = tm + ts + (tc-tm) = t in the device of the present invention.
s + tc, and therefore the cooling pitch of the device of the present invention is (tp-t) below the cooling pitch of the device of the comparative example.
The time will be shortened by'p). tp−t′p = {2 × (tm + ts) + tc} − (ts
+ Tc) = 2tm + ts

[0009]

2 to 4 show one embodiment of the device of the present invention. The device of the present invention comprises a cooling device 1 capable of simultaneously cooling the entire length of a rail after hot rolling, a rail loading device 2a and a rail unloading device 2b arranged on both sides of the cooling device 1 in parallel therewith, and a rail loading device. It is composed of a slewing / carrying-in device 3a which is carried in from the device 2a to the cooling device 1 while being carried in, and a slewing / carrying-out device 3b which is carried out while the rail is being rolled from the cooling device 1 to the rail unloading device 2b.

The cooling device 1 includes refrigerant cooling headers 5a and 5b for cooling the rail head top portion and rail head side portion which can be moved up and down, and a plurality of rails provided at appropriate intervals in the longitudinal direction of the device. It is composed of a foot supporting / constraining device 4 and a coolant injection header 5c for cooling the bottom of the rail which is arranged below the rail supporting position by this device. Each of the refrigerant injection headers 5a, 5b, 5c has a refrigerant injection nozzle.

A pedestal 16 is provided on the upper part of the cooling device 1, and an elevating frame 18 is held on the pedestal 16 via an elevating device 17 (cylinder device) so as to be vertically movable. The refrigerant jet headers 5a and 5b for cooling the rail head top portion and the rail head side portion are mounted and fixed to the elevating frame 18.

The rail foot supporting and restraining device 4 has a pair of claws 15 for holding both sides of the rail foot. The rail foot supporting / constraining device 4 is arranged at four positions in the longitudinal direction of the device (usually at intervals of about 1.5 to 5 m) and is fixed to a support frame 19 arranged at the lower part of the device. The support frame 19 constitutes an oscillation mechanism 6 which will be described later, and includes a traveling roller 21 that rolls on a base 22.
Is configured so that it can be moved back and forth in the longitudinal direction of the device. The coolant injection header 5c for cooling the rail sole is
It is arranged below the rail supporting position by the rail foot supporting / constraining device 4, and has discontinuities in the arrangement portions of the respective rolling / carrying-in devices 3a and rolling / carrying-out devices 3b.

The rail loading device 2a and the rail unloading device 2b are devices for transporting the rail in the extending direction,
It is arranged on both sides of the cooling device 1 in parallel with it. Each of the rail carry-in device 2a and the rail carry-out device 2b has a plurality of table rollers 23. Each of the rolling-in / carrying-in device 3a and the rolling-in / carrying-in device 3b has a holding body 7 having a receiving surface 70 having an L-shaped cross section for holding a rail. In this embodiment, the rail-carrying-in device 2a and the cooling device. 1
, And each of the rail unloading device 2b and the cooling device 1 are provided at three places with appropriate intervals.

FIG. 4 shows a specific structure of the turning-in / carrying-out device 3a and the turning-out / carrying-out device 3b. Each device is provided with a lifter 8 which can be lifted and lowered by a lifter 9, and rails for the lifter 8. A carriage 10 provided so as to be movable between the carry-in device 2a or the rail carry-out device 2b and the cooling device 2, and this carriage 10
Cylinder device 12 for driving the vehicle, and the carriage 10
The holder 7 pivotally attached 14 to the tip of
It is composed of a cylinder device 13 for rotating the holding body 7. In the figure, 11 is a traveling roller of the carriage, 120 is an operating rod of the cylinder device 12, and 130 is an operating rod of the cylinder device 13.

According to such an apparatus, the rail can be conveyed by moving the carriage 10 while the rail is held by the receiving surface 70 of the holder 7, and the cylinder device 13 is actuated to hold the rail. By rotating 7 about 90 °, the rail held on the receiving surface 70 can be freely rotated about 90 °, that is, between the upright state and the sideways state. The holding body 7 is indicated by a broken line x in FIG. 2 when the lifter 9 is moved up and down and the carriage 10 is moved in order to avoid interference with the table roller 23 and the rail foot support / restraint device 4. Move along the trajectory to carry in and out the rail.

Further, in this embodiment, there is provided an oscillation mechanism 6 for oscillating the rail foot supporting / constraining device 4 in the longitudinal direction of the rail. Japanese Patent Fair 1-130
In the conventional heat treatment apparatus as disclosed in Japanese Patent Publication No. 12, a part of the bottom of the rail is always covered by a transfer or the like which is a stacking type transfer device, so that this portion is not exposed to the cooling gas, and a predetermined amount is not provided. There is a problem that the cooling rate cannot be obtained. As a result of such a portion having a low cooling rate, there is a drawback that the quality of the foot sole portion becomes uneven.

Therefore, in this embodiment, the rail foot supporting / constraining device 4 is oscillated (reciprocatingly moved) in the longitudinal direction of the rail by the oscillation mechanism 6 to cool the bottom of the rail at a uniform cooling speed. This is to ensure uniform quality in the longitudinal direction of the foot. The oscillation mechanism 6 includes the support frame 19 that can move forward and backward in the device longitudinal direction, and a cylinder device 20 in which an operating rod is connected to one end of the support frame 19. The cylinder device 20 moves the support frame 19 in the device longitudinal direction. The rail foot supporting and restraining device 4 can be oscillated in the longitudinal direction of the rail.

In this embodiment, the rail foot supporting / constraining device 4 for restraining the rail is made to oscillate in the longitudinal direction of the rail. However, in some cases, the refrigerant injection header 5c for cooling the sole of the rail is used for the rail. The structure may be such that it oscillates in the longitudinal direction. In other drawings,
Reference numeral 24 is a supply pipe for supplying a refrigerant such as air to the respective refrigerant injection headers, 25 is a flow rate adjusting valve provided in these supply pipes, and 29 is a refrigerant conduit through which the supply pipes 24 are supplied with the refrigerant. Each of the supply pipes 24 of the refrigerant injection headers 5a and 5b has an expansion tube portion or a flexible tube portion (not shown) in the middle thereof in order to enable the refrigerant injection headers to move up and down.

Further, in the above embodiment, the refrigerant jet header 5a for cooling the rail head portion and the refrigerant jet header 5b for cooling the rail head side portion are integrally moved up and down via the elevating frame 18. In some cases, it is possible to attach both refrigerant injection headers to different elevating frames so that they can be individually moved up and down.

FIGS. 5 and 6 show a preferred embodiment of the rail foot supporting / constraining device 4, in order to ensure cooling of the constrained portion of the rail foot on which the pawl 15 abuts,
The structure is such that the refrigerant can be supplied to the inner side of 5. That is, the portion of the claw 15 that restrains the rail foot is
A plurality of refrigerant supply holes 30 opening to the rail contact surface 151 of the pawl 15 are formed, and the rail contact surface 15 of the pawl 15 is further formed.
1 is formed with a groove 31 extending in a plurality of directions from each of the coolant supply holes 30. In this embodiment, the rail contact surface 1
Grooves 31 are formed in a grid pattern at 51, and the openings of the coolant supply holes 30 are located at the intersections of the grooves 31. Then, the refrigerant is supplied to each of the refrigerant supply holes 30 through a supply pipe (not shown), and the refrigerant flows along the groove 31, whereby the claw 1
The constrained portion of the rail foot on which 5 abuts is cooled.

Next, an example of rail cooling processing by the apparatus of the present invention will be described by taking the apparatus shown in FIGS. 2 to 4 as an example. 7 to 9 show stepwise a procedure of the rail cooling process by the apparatus shown in FIGS. 2 to 4.

FIG. 7A shows a state in which the rail A ₁ is transported from the rolling line by the rail loading device 2a. From this state, as shown in FIGS. 7B and 7C, the rail A in which the holding body 7 of the turning / carrying-in device 3a is in the sideways state.
_It is moved to the lower part of ₁ , and is lifted up and conveyed to the cooling device 1. As shown in (d) of FIG. 7, the holding body 7 is rotated about 90 ° during the transportation to turn the rail A ₁ to the upright state. As shown in (e) and (f) of FIG. 8, the rail A ₁ is conveyed to directly above the refrigerant injection header 5c, and then lowered to the rail supporting position. In this state, as shown in FIG. 8 (g), the pawls 15 of the rail foot supporting / constraining device 4 in the open state are operated, and the pawls 15 support and constrain both sides of the rail foot. ..

Next, as shown in FIG. 8 (h), the holding body 7 is retracted to the outside of the cooling device, and the elevating device 17 is used to cool the top of the rail head and to cool the side of the rail head. And 5b are lowered to the cooling processing position. In this state, each refrigerant injection header 5
Refrigerant such as air is supplied from the nozzles a, 5b and 5c to the rail A.
_It is injected to each part of ₁ to cool the rail A ₁ . This cooling process is usually performed for about 90 seconds to 150 seconds. By the time the cooling of the rail A ₁ is completed, the next cooling rail A ₂ is carried in by the rail loading device 2a as shown in (i) of FIG.
It stands by at the side of the cooling device 1.

After cooling the rail A ₁ , as shown in (j) and (k) of FIG. 9, the refrigerant injection headers 5a and 5b rise and the rail foot support / restriction device 4 releases the rail restraint. Then, the rail A ₁ is unloaded to the rail unloading device 2b while being rolled sideways by the tumbling and unloading device 3b, and in synchronization with this, the rail A ₂ waiting on the rail unloading device 2a rolls. The carry-in device 3a carries the product into the cooling device 4 while turning it from the sideways state to the upright state, and the next cooling is performed. Through the above cycle, the cooling of the rail A and its loading / unloading are sequentially performed.

In the apparatus of the present embodiment, during the cooling of the rail, the cylinder frame 20 causes the support frame 19 to reciprocate in the longitudinal direction of the rail.
And the rail A restrained by this is oscillated in its longitudinal direction. With such oscillation, the entire bottom of the rail sole as shown in FIG. 11 can be cooled at a uniform cooling rate.

That is, considering quality unevenness of the rail hardness imparted by cooling in the rail longitudinal direction,
As shown in FIG. 11, a cooling medium injection header 5c for cooling the bottom of the rail (5a is a cooling medium injection header for cooling the top of the rail)
When the discontinuity part of is a distance a, in the conventional device, a part cooled by the header and a part not cooled are mixed in the longitudinal direction of the rail A, and there are a part having high hardness and a part having low hardness due to cooling. The quality becomes uneven. On the other hand, in the apparatus of the present embodiment, as shown in FIG. 11, the rail A (or the refrigerant injection header 5c) is cooled while oscillating by a certain distance b in the longitudinal direction, and therefore, the discontinuous portion of the refrigerant injection header 5c. Even if there is, it is possible to avoid that the refrigerant uniformly hits the entire length of the rail and uneven quality in the longitudinal direction of the rail occurs.

Actually, after rolling, 50N rail (C: 0.77 wt%, S) which retains heat of austenite region temperature
i: 0.25 wt%, Mn: 0.89 wt%, P: 0.
(017 wt%, S: 0.007 wt%), the hardness of the sole part when cooled in the state where the discontinuous portion of the refrigerant injection header exists as shown in FIG. 11 is approximately the following relational expression. Can be represented. HV (h) ≈0.5 × t + HV (n) t = T × (1-a / b) However, HV (h): HV hardness of the refrigerant injection header discontinuous portion HV (n): No cooling (natural cooling) ) HV hardness of the track t: Cooling time of the refrigerant injection header discontinuous portion T: Cooling time of the refrigerant injection header continuous portion a: Length of the refrigerant injection header discontinuous portion b: Oscillation length

According to this, when the length a of the discontinuous portion of the refrigerant injection header is 200 mm and the cooling time T is 120 seconds,
In the case of no oscillation, a hardness difference of HV60 occurs between the continuous portion and the discontinuous portion of the refrigerant injection header, but by performing the oscillation at b: 1000 mm, for example,
The difference in hardness between the continuous portion and the discontinuous portion of the refrigerant injection header is HV1.
It is possible to reduce it to 2.

The predetermined cooling rate required for heat treatment of the rail head is set by the rail head and each refrigerant injection header 5a,
5b, and the amount of the refrigerant injected from each refrigerant injection header is adjusted. The distance between the rail head and each refrigerant injection header is adjusted by adjusting the height of the elevating frame 18, and the amount of refrigerant injection is adjusted by the flow rate adjusting valve 25 provided in each supply pipe 24. Further, the refrigerant injection amount of the refrigerant injection header 5c for cooling the sole of the rail is also adjusted by the flow rate adjusting valve 25 of the supply pipe 24. The cooling of the bottom of the rail is performed in consideration of the balance with the cooling of the head of the rail in order to minimize the bending amount of the rail. During cooling of the rail, a temperature detector (not shown) provided above the rail detects the temperature of the top of the rail, and the flow rate adjusting valve 25 is closed at the time when the rail is cooled to a predetermined temperature based on this temperature detection. To stop cooling.

[0030]

As described above, according to the device of the present invention,
During cooling of the rail in the cooling device, the next cooling rail stands by at the cooling device loading position, and it is possible to carry out the already cooled rail from the cooling device and carry in the next cooling rail to the cooling device almost at the same time. Therefore, it is possible to perform an efficient heat treatment with a reduced non-cooling loss time, and it is possible to suppress the reduction of the hot rolling efficiency due to the insufficient treatment capacity of the conventional heat treatment apparatus as much as possible.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the basic configuration of the device of the present invention and its usage state.

FIG. 2 is a front view showing an embodiment of the device of the present invention.

FIG. 3 is a plan view of the device shown in FIG.

FIG. 4 is a side view showing the details of a turning-in / carrying-in device and a turning-carrying-out device in the apparatus of the present invention shown in FIGS. 2 and 3.

FIG. 5 is a partial side view showing a preferred embodiment of the rail foot supporting and restraining device, showing a state in which the rail foot is restrained by a pawl.

6 is an arrow view taken along line VI-VI in FIG.

FIG. 7 is an explanatory diagram showing stepwise a procedure of rail cooling processing by the device of the present invention.

FIG. 8 is an explanatory view showing the steps of the rail cooling process by the device of the present invention step by step.

FIG. 9 is an explanatory view showing steps of a rail cooling process by the device of the present invention step by step.

FIG. 10 is a drawing showing a time cycle of rail cooling by the device of the present invention.

11 is an explanatory diagram showing a range of oscillation by the apparatus of FIG.

[Simple explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cooling device, 2a ... Rail carrying-in device, 2b ... Rail carrying-out device, 3a ... Rolling / carrying-in device, 3b ... Rolling-carrying-out device, 4
… Rail foot support / restriction devices 5, 5 ', 5a, 5b, 5
c ... Refrigerant injection header

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenichi Sakai 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd.

Claims (1)

[Claims] 1. A cooling device capable of simultaneously cooling the entire length of a rail after hot rolling, and a device for transporting the rail in its extending direction, the rail loading device being arranged on both sides of the cooling device in parallel with the cooling device. And a rail carry-out device, a roll-in / carry-out device that carries in the rail while rolling it from the rail carry-in device to the cooling device, and a roll-carry-out device that carries out the rail while rolling the rail from the cooling device to the rail carry-out device. Heat treatment equipment.