DEVICE FOR THERMALLY PROCESSING RAILS

Abstract

 The invention relates to the field of metallurgy and, in particular, to the thermal processing of rails, including railroad rails.
The proposed invention for thermally processing rails allows for simultaneously solving the problem of coupling a pipeline and a collector when the coupled surfaces thereof differ in form and achieving a gradual change of a flow of coolant medium at the entrance to the collector, and also allows for dividing the flow of coolant medium inside the collector.
Together, these features allow for equally distributing a flow of coolant medium in a collector and for achieving the required (specified) equal distribution of coolant medium on the surface of a rail.

Description

TECHNICAL FIELD

[0001] The invention relates to the field of metallurgy, in particular, to the thermal processing of rails including railroad rails.

BACKGROUND OF THE INVENTION

[0002] RU2450877 (WO 2009/107639) describes a system of cooling a hot-rolled long steel beam, in particular, a rail, the system including a plurality of chambers arranged along the rolled steel beam, each of said chambers having a blowing hole facing the rolled steel beam and configured to blow cooling forced air fed into the chamber through a gas input port that is in fluid communication with the chamber; a nozzle plate having a plurality of nozzle orifices, the nozzle plate being located on the blowing hole so that the nozzle plate faces the rolled steel beam; a nozzle for feeding cooling water into the chamber; and a straightening plate located between the gas input port and the nozzle for feeding cooling water and configured to prevent from a direct impact of the cooling forced air fed through the gas input port on the nozzle plate; the cooling system being configured to spray a coolant medium obtained by mixing said cooling water fed through the nozzle with said cooling forced air fed through the gas input port and straightened by said straightening plate in the direction of the rolled steel beam through said nozzle orifices of the nozzle plate in order to provide uniformly cooling the surfaces of the rolled steel beam.

[0003] This method is characterized in that the thermally processing a rail is effected by a medium with a continual cooling ability, which fails to provide flexibly changing the cooling rate during thermally processing one rail in order to ensure optimal characteristics thereof.

[0004] It is a disadvantage of this system that its water-feeding nozzles are located downstream the straightening plate and feed water directly to the nozzle plates, which does not provide the achievement of a sufficiently uniform distribution of water in air. Therefore, a non-uniform distribution of the coolant medium (water and air mixture) on the nozzle plate takes place. This results in non-uniformly spraying the coolant medium through the nozzle orifices and, consequently, in non-uniformly cooling the surface of the rail (steel beam) subjected to thermal processing.

[0005] Another disadvantage of this system consists in means for achieving the uniformity of distribution of air within the chamber, i.e., in the straightening plate horizontally positioned in a wider portion of the chamber with such a gap that the cooling forced air passing between the side edges of the straightening plate and the inner walls of said wider portion of the chamber is uniformly distributed in a narrower portion thereof. In the opinion of the inventors, in order to provide the uniformity of distribution of air within the chamber, strict requirements shall be specified to the accuracy of positioning the straightening plate, as even slight deflections of positioning the plate during assembly operations cause a dramatic redistribution of air in the chamber.

[0006] Further, the technical result declared in this patent depends on the form of the chamber which includes a wider portion that is made such in order to provide input of gas; a narrower portion having a lesser width than the wider portion; and a sloped portion interconnecting said wider and narrower portions; the blowing hole being located at the end of the narrower portion of the chamber.

[0007] Such a complex form of the chambers is a disadvantage in terms of design, arrangement and installation of devices for thermally processing rails. Experience has shown that the form of collectors is a function of specific conditions of engineering design of thermal processing equipment, and there are good reasons to use different forms of upper, lower, and lateral collectors, e.g., for thermally processing variable-profile and/or nonsymmetrical-profile rails or long rolled steel profile, or in case of engineering design of said equipment in a space-limited industrial environment.

[0008] RU2456352 discloses a method and device for thermally processing a rail, the device comprising
units of loading, unloading, positioning, and holding the rail,
a turbo-compressor,
a system of air-ducts and collectors with nozzle orifices for feeding a coolant medium simultaneously onto both top and underside of the rail,
units of positioning said air-ducts and collectors with nozzle orifices,
a system of controlling delivery of coolant medium,
a system of temperature control, the device being characterized in that it has a system of pulsewisely quasicontinuously and/or continuously injecting water into an air flow, the system comprising
a container for water,
a water pipework,
flow-rate and pressure controllers made as controlled valves and controlled regulation valves,
pulse injectors governed by an injection control unit for injecting, in a pulsewise quasicontinuous and/or continuous mode, water into a flow of air medium with adjustably changeable humidity and pressure of the air in order to change the cooling ability of the medium,
said units of loading, unloading, positioning, and holding the rail being configured to provide the upside down position of the rail during the processing thereof.

[0009] This technology makes it possible to select the mode of cooling and to control the rate of cooling the rail. However, it does not solve the problem of non-uniformity of the coolant medium flow distribution at the input thereof into the collector because of an abrupt change of the flow velocity owing to difference of sectional areas, namely, because the sectional area of the gas pipeline is significantly smaller than that of the collector, which causes an insufficiently uniform distribution of the coolant medium in the collector.

BRIEF DESCRIPTION OF THE INVENTION

[0010] The technical result of the invention consists in simultaneously coupling differently shaped coupling surfaces of the gas pipeline and collector and in smoothly changing the velocity flow of the coolant medium entering the collector, as well as in dividing the flow of the coolant medium within the collector, which cumulatively facilitates to achieve a more uniform distribution of the coolant medium flow within the collector and a specified uniform distribution of the coolant medium on the surface of the processed rail.

[0011] This technical result is achieved in a device for thermally processing a rail, comprising
a gas pipework,
a water pipework,
a unit for pulsewisely quasicontinuously and/or continuously injecting water into a gas flow, the unit comprising pulse injectors governed by an injection control unit for injecting, in a pulsewise quasicontinuous and/or continuous mode, water into a flow of gas medium with adjustably changeable humidity and pressure of the gas in order to change the cooling ability of the medium,
cooling modules, each of which comprising an upper and/or lateral and/or lower collector for feeding coolant medium simultaneously onto both top and underside of the rail,
wherein, according to the invention, the pipes of said gas pipework are coupled with said collectors through transition flanges with built-in injectors with discharge openings directed into said pipes of the gas pipework in order to form the coolant medium, dividers being installed at least in the upper collectors.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] 

Fig. 1 schematically illustrates the arrangement of the cooling modules of the device of invention, the number reference signs designating:

1 - rail,

2 - cooling module,

3 -upper collector,

4 - lateral collector,

5 - lower collector.

Fig. 2 schematically illustrates a cooling module of the device of invention, the number reference signs designating:

1 - rail,

2 - cooling module,

3 -upper collector,

4 - lateral collector,

5 - lower collector,

6 - gas pipework,

7 - water pipework,

8 - control unit,

9 - perforated screen with guide holes,

10 - transition flange,

12 - injector.

Fig. 3 schematically illustrates a collector with a transition flange according to a first embodiment of the device of invention, the number reference signs designating:

6 - gas pipework (fragment),

10 - transition flange,

12 - injector,

13 - divider.

Fig. 4 schematically illustrates a cross-section of a rail and the perforated screens of collectors, the number reference signs designating:

1 - rail,

9 - perforated screen,

9a - guide holes.

Fig. 5 schematically illustrates a divider in a collector of the device of invention, the number reference signs designating:

9 - perforated screens,

9a - guide holes,

11- intake opening,

13 - divider,

b - width of the perforated screen,

f - distance between the divider and the perforated screen,

l - width of one pitch of the divider,

p - width of the intake opening of the collector,

ϕ - angle formed by the pitches of the divider.

Fig. 6 schematically illustrates a collector with a transition flange according to a second embodiment of the device of invention.

Fig. 7 schematically illustrates a collector with a transition flange according to a third embodiment of the device of invention.

Fig. 8 schematically illustrates a collector with a transition flange according to a fourth embodiment of the device of invention.

Fig. 9 schematically illustrates a collector with a transition flange according to a fifth embodiment of the device of invention.

Fig. 10 schematically illustrates a collector with a transition flange according to a sixth embodiment of the device of invention.

Fig. 11 schematically illustrates a collector with a transition flange according to a seventh embodiment of the device of invention.

Figs. 12a-d show diagrams of hardness distribution over the length of the rail.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

[0013] As shown in Fig. 1, cooling modules 2 are arranged in series along a rail 1. The number of the cooling modules 2 is determined in order to provide simultaneously cooling the entire length of the rail 1. Each cooling module 2 may comprise: an upper collector 3 and/or one or two lateral collectors 4 and/or a lower collector 5, that are arranged along respective surface of the rail 1 subjected to cooling. The collectors 3, 4, and 5 are in fluid communication with gas pipework 6, which is communicated with water pipework 7. Control unit 8 provides injecting, in a pulsewise quasicontinuous and/or continuous mode, water into a flow of gas.

[0014] Preferably, each of the collectors 3, 4, and 5 is formed as a longitudinally oriented parallelepiped, as shown in Fig. 3, or in any different shape in accordance with the type of surface subjected to thermally processing and conditions of assembling of the cooling modules 2. Some optional versions are illustrated in Figs. 6-11. Each of the collectors 3, 4, and 5 has an intake opening 11 providing intake of coolant medium, the face of the collector fronting the surface of the rail being formed as a perforated screen 9 (Fig. 2) having guide holes 9a (Figs. 4 and 5) for feeding the coolant medium onto the surfaces of the rail subjected to thermally processing. The area of said intake opening 11 of the collector may be less than or equal to that of the perforated screen 9. Besides, the intake opening 11 of the collector 3, 4, and/or 5 may be oriented either parallel, or at an angle to said perforated screen 9. As shown in Figs. 2 and 3, the gas pipework 6 is coupled with the collector 3, 4, and/or 5 through a transition flange 10, which optimally provides coupling a corresponding pipe of the pipework 6 with the collector 3, 4, or 5, the two coupled parts being significantly different as to the shape of the surfaces to be coupled, a gradual change of the flow of coolant medium at the entrance to the collector being simultaneously achieved.

[0015] As shown in Fig. 3, the transition flange 10 has a built-in injector 12, so that the discharge opening of the latter is directed into said pipe of the gas pipework 6 in order to form coolant medium. As shown in Figs. 3 and 5, a divider 13 is installed in the collector 3, 4, and/or 5 to provide dividing of the coolant medium flow within the collector. Said divider 13 has a two-pitched surface (Fig. 5). The length of the divider 13 is usually in a range of between 50% and 90% of the length of the collector, and the width I of one pitch of the divider 13 is calculated using the following formula:

where

b - width of the perforated screen 9 of the collector;

p - width of the intake opening 11 of the collector; and

ϕ - angle formed by the pitches of the divider 13, ϕ<180°.

[0016] In case I = b/(2sin(ϕ/2)), the divider would occlude the cross-section of the collector completely, and the whole flow of the coolant medium would be directed from the intake opening 11 only to the butt-end areas of the collector, which would cause non-uniformity in the coolant medium flow on the rail surface.

[0017] In case I < p/(2sin(ϕ/2)), a portion of the coolant medium would flow directly to the guide holes 9a of the perforated screen 9, which would cause flow non-uniformity as well. This would lead to a higher velocity of the coolant medium flow from the guide holes 9a and, consequently, to a higher rate of cooling the rail surface in these areas, which would result in non-uniformity in the properties of the rail over its length.

[0018] In case of arranging the divider 13 symmetrically about the intake opening 11, the flow would be divided into two equal parts.

[0019] It is conceivable to use a divider 13 with its surface perforated with round holes and/or openings of rectangular or other shape. Besides, the divider 13 may have a variable width changing over its length.

[0020] The use of transition flanges, two-pitched dividers, and perforated screens with guide holes allows using collectors of various shapes enabling a differentiated thermal processing (depending on the type of the thermally processed item).

[0021] Preferably, the dividers 13 are installed in the collectors 3, 4, and 5. Also, here are conceivable such embodiments of the device where the divider 13 is installed only in the collectors 3 or 4, or 5, or 3 and 4, or 3 and 5, or 4 and 5, which would allow using the device, e.g., for processing rails of a non-uniform and/or non-symmetrical profile, or long symmetrical and/or non- symmetrical rolled steel profile.

[0022] The device operates in the following manner:

The devise provides conducting an adjustable differentiated cooling in both feed-through and in-and-out modes. In the feed-through cooling mode, the rail is moved relative to the cooling modules with a programmatically preset velocity. In the in-and-out cooling mode, the rail is held motionless relative to the cooling modules. The rail 1 is delivered from rolling or separate heating into a quenching device and positioned relative to the cooling modules 2. The cooling is started from a temperature not lower that the austenitisation temperature.

[0023] Gas is fed through gas pipework 6 by a turbine compressor (not shown). Water delivered through water pipework 7 is injected into said gas pipework 6 by injectors 12 inbuilt in the transition flange 10 is injected into said gas pipework 6, where intermixing of the water and gas results in forming a coolant medium. A control unit 8 adjusts the mass-flow rate of the gas in accordance with the environmental temperature and humidity, ensuring a preset pressure in the collectors 3, 4, and 5, and the mass-flow rate of the injected water, thereby adjusting the mass ratio therebetween in a preset range in order to obtain a coolant medium having preset characteristics, which provides a preset (constant / required) flow velocity of the coolant medium.

[0024] The thus formed coolant medium flowing out of the gas pipework 6 flows through the transition flange 10, which helps reduce the flow resistance thereof, and, through an intake opening 11, is fed into the collectors 3, 4, and 5, wherein a divider 13 divides the flow of the coolant medium and provides the uniformity of distribution thereof over the volume of each of said collectors.

[0025] Further, the coolant medium is directed to corresponding surfaces of the rail 1 via guide holes 9a of a perforated screen 9 of each of the collectors 3, 4, and 5.

EXAMPLE OF IMPLEMENTATION

[0026] Full-profile 1.6 meter long specimens of P-65 type rail were subjected to thermally processing. Two cooling modules were installed in series along the rail, said cooling modules comprising one upper collector, two lateral collectors, and one lower collector in order to estimate the uniformity of the flow on the rail surface both over the length of any one collector and in the places of joining the cooling modules. The rail specimens were made of steel K76F of the same cast having the following chemical composition:

C - 0.78%,

Mn - 0.93%,

Si - 0.36%,

V - 0.077%,

Cr - 0.038%,

P - 0.009%, and

S - 0.004%.

[0027] The rail specimens were heated in a proof-of-concept furnace of an in-and-out type. The temperature of heating the rail specimens for hardening was 850°C. The rail specimens were cooled in accordance with a mode programmatically preset for this chemical composition of the rail cast as disclosed in RU2456352 using the device according to the invention.
Rail specimens of the same type were tested also in a feed-through mode as described in patent applications RU2011131883 and RU2011144110.

[0028] Full-profile templates were used to evaluate the macroscopic and microscopic structures of the thermally processed specimens. No dark and bright fringes were observed in the macroscopic structure. As for the microscopic structure, a various dispersion pearlite was observed.

[0029] The uniformity of the thermal processing of the rails over the length of the collectors was evaluated based on the Brinell hardness thereof measured on the rail head running surface in 50 mm increments subsequent to removal of a 0.50 mm decarburized layer from the surface. Distribution diagrams of the Brinell hardness over the rail head running surface are shown in Fig. 12.

a) for the device of invention in its in-and-out mode of operation using a divider but without using a transition flange;

b) for the device of invention in its in-and-out mode of operation using a transition flange but without using a divider;

c) for the device of invention in its in-and-out mode of operation with both a transition flange and a divider;

d) for the device of invention in its feed-through mode of operation with both a transition flange and a divider.

In Fig. 12a, the Brinell hardness dispersion is within 25 HB, in Fig. 12b - 50 HB, in Fig. 12c and 12d - less than 10 HB, thus confirming the best result in respect of the uniformity of cooling the rail.

INDUSTRIAL APPLICABILITY

[0030] The device for thermally processing rails according to the invention allows for simultaneously solving the problem of coupling a pipeline and a collector when the coupled surfaces thereof differ in form and achieving a gradual change of a flow of coolant medium at the entrance to the collector, and also allows for dividing the flow of coolant medium inside the collector, these features together allowing for equally distributing a flow of coolant medium in a collector and for achieving the required (specified) equal distribution of coolant medium on the surface of a rail.

Claims

1. A device for thermally processing rails comprising:

- a gas pipework,

- a water pipework,

- a unit for pulsewisely quasicontinuously and/or continuously injecting water into a gas flow, the unit comprising pulse injectors governed by an injection control unit for injecting, in a pulsewise quasicontinuous and/or continuous mode, water into a flow of gas medium with adjustably changeable humidity and pressure of the gas in order to change the cooling ability of the medium,

- cooling modules, each of which comprises an upper and/or lateral and/or lower collector for feeding coolant medium simultaneously onto both top and underside of the rail,

characterized in that the pipes of said gas pipework are coupled with said collectors through transition flanges with built-in injectors with discharge openings directed into said pipes of the gas pipework in order to form the coolant medium, dividers being installed at least in the upper collectors.

2. The device according to claim 1, wherein said collectors together constitute cooling modules, each of which comprises at least one upper collector, two lateral collectors, and one lower collector.

3. The device according to claim 1, wherein said collector is preferably formed as a longitudinally oriented parallelepiped.

4. The device according to claim 1, wherein an intake opening of the collector may be oriented at an angle to a perforated screen of the collector.

5. The device according to claim 1, wherein the area of an intake opening of the collector is less than or equal to the area of a perforated screen of the collector.

6. The device according to claim 1, wherein said transition flange is formed as a frustum of pyramid to couple said gas pipework with the collector.

7. The device according to claim 1, wherein said divider has a two-pitched surface.

8. The device according to claim 1, wherein the angle formed by the pitches of the divider is specified depending on the width of the intake opening, the width of a perforated screen having guide holes, and the distance between the divider and said perforated screen.

9. The device according to claim 1, wherein the length of the divider is in a range of between 50% and 90% of the length of the collector, and the divider is arranged symmetrically about the intake opening of the collector.

10. The device according to claim 1, wherein the surfaces of the divider may be perforated with round holes and/or openings of rectangular or other shape.

11. The device according to claim 1, wherein the divider may have a variable width changing over its length.

12. The device according to any of claims 1 or 3, wherein the collector may be formed as a reservoir with a round cross-section.

13. The device according to any of claims 1, 3, or 12, wherein the collector may be formed as a reservoir with a polygonal cross-section.

Drawing