CN109338075B - On-line heat treatment method for rail web of turnout steel rail and restraining device thereof - Google Patents
On-line heat treatment method for rail web of turnout steel rail and restraining device thereof Download PDFInfo
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- CN109338075B CN109338075B CN201811378013.7A CN201811378013A CN109338075B CN 109338075 B CN109338075 B CN 109338075B CN 201811378013 A CN201811378013 A CN 201811378013A CN 109338075 B CN109338075 B CN 109338075B
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- rail
- steel rail
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/04—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rails
Abstract
The invention discloses an on-line heat treatment method for a turnout steel rail web and a restraint device thereof in the technical field of metal heat treatment, which comprises the following steps of firstly, controlling the temperature of a steel rail at 700-800 ℃, wherein the percentage content of carbon is between 0.7 and 0.90 percent; then, the steel rail is sent into a restraint device, and an accelerating cooling medium is applied to the center of the tread of the rail head, the two sides of the rail head and the center of the rail bottom of the steel rail by using the restraint device, wherein the cooling speed is 1-5 ℃/s; and finally, when the temperature of the steel rail is reduced to 450-500 ℃, the steel rail is sent out of the restraint device. The invention has the beneficial effects that: the restraining device is used for stabilizing the steel rail, and then an accelerating cooling medium is applied to the rail head and the rail bottom of the steel rail, so that the temperature of the rail head and the rail bottom is rapidly reduced, the heat of the rail web part is rapidly conducted to two ends, the residual stress of the rail web of the steel rail is reduced, and the comprehensive performance of the rail web of the turnout steel rail is improved.
Description
Technical Field
The invention relates to the technical field of metal heat treatment, in particular to an on-line heat treatment method for a turnout steel rail web and a restraint device thereof.
Background
The turnout is an important part for guiding the train to turn by a railway line, and the thickness of the rail web of the turnout rail reaches 44mm at most, which is 2-3 times of that of a common rail. In the on-line heat treatment process of the turnout steel rail, rail web heat is difficult to dissipate, and the heat treatment strength of the rail head is influenced by the rail web heat, so that the performance of the rail head with the same components is lower than that of a common steel rail. Meanwhile, the turnout rail head and the rail web are complex in stress and harsh in use condition, and are always one of the weakest links of a railway line for many years, so that the rapid development of the railway is severely restricted. At present, in the heat treatment process of the turnout steel rail, all-round cooling is generally adopted, and the cooling speed and the cooling effect are poor, so that a heat treatment method capable of improving the comprehensive performance of the turnout steel rail is needed to be researched.
Disclosure of Invention
In order to overcome the defects of poor cooling effect and the like of the existing turnout steel rail, the invention aims to solve the technical problems that: provides an on-line heat treatment method capable of improving the comprehensive performance of the rail web of the turnout steel rail and a restraint device thereof.
The technical scheme adopted by the invention for solving the technical problems is as follows:
an on-line heat treatment method for a turnout steel rail web comprises the following steps:
firstly, controlling the temperature of the steel rail at 700-800 ℃, wherein the percentage content of the carbon content is between 0.7 and 0.90 percent;
then, the steel rail is sent into a restraint device, and an accelerating cooling medium is applied to the center of the tread of the rail head, the two sides of the rail head and the center of the rail bottom of the steel rail by using the restraint device, wherein the cooling speed is 1-5 ℃/s;
and finally, when the temperature of the steel rail is reduced to 450-500 ℃, the steel rail is sent out of the restraint device.
Further, the cooling medium is air blast or spray.
Further, the pressure of the cooling medium ejection is: v is (T1-700)/60+ G/20-1.5, wherein T1 is the rail web temperature of the steel rail entering unit, the unit is the temperature, and G is the thickness of the rail web, and the unit is mm.
The restraint device for carrying out on-line heat treatment on the rail web of the turnout steel rail comprises a fixed frame and a cooling device; the top of the fixing frame is provided with a bottom restraint wheel, two sides of the fixing frame are provided with rocker arms, the upper ends of the rocker arms are provided with guide plates, the inner sides of the guide plates are provided with upper restraint wheels, the rail bottom of the steel rail is placed on the bottom restraint wheel, and the upper restraint wheels respectively abut against two sides of the rail web of the steel rail; and the cooling device is provided with a plurality of nozzles which respectively face the center of the tread of the rail head of the steel rail, two sides of the rail head and the center of the rail bottom.
Furthermore, the middle part of the rocker arm is hinged with the fixed frame, and the lower end of the rocker arm is connected with the fixed frame through an adjusting bolt.
Furthermore, the length of the guide plate is 1-2 m, and two groups of rocker arms are arranged at intervals in the length direction of the guide plate.
The invention has the beneficial effects that: the restraining device is used for stabilizing the steel rail, and then an accelerating cooling medium is applied to the rail head and the rail bottom of the steel rail, so that the temperature of the rail head and the rail bottom is rapidly reduced, the heat of the rail web part is rapidly conducted to two ends, the residual stress of the rail web of the steel rail is reduced, and the comprehensive performance of the rail web of the turnout steel rail is improved.
Drawings
Fig. 1 is a front view of the present invention.
Fig. 2 is a side view of the present invention.
Marked in the figure as 1-fixed frame, 2-cooling device, 3-bottom restraint wheel, 4-rocker arm, 5-guide plate, 6-upper restraint wheel, 7-steel rail, 8-nozzle and 9-adjusting bolt.
Detailed Description
The invention is further illustrated with reference to the following figures and examples.
The invention provides an on-line heat treatment method for a rail web of a turnout steel rail, which comprises the following steps:
firstly, controlling the temperature of the steel rail at 700-800 ℃, wherein the percentage content of the carbon content is between 0.7 and 0.90 percent; then, the steel rail is sent into a restraint device, and an accelerating cooling medium is applied to the center of the tread of the rail head, the two sides of the rail head and the center of the rail bottom of the steel rail by using the restraint device, wherein the cooling speed is 1-5 ℃/s; and finally, when the temperature of the steel rail is reduced to 450-500 ℃, the steel rail is sent out of the restraint device.
The temperature and the carbon content of the steel rail determine the strength of the steel rail in the heat treatment process, the traditional cooling mode is slow, carbon is easily separated out, the residual stress of the steel rail is not easy to release, and the like, so that the performance of the rail web of the steel rail is not enough. The invention applies accelerating cooling medium to the center of the tread of the rail head, the two sides of the rail head and the center of the rail bottom, so that the temperature of the rail head and the rail bottom of the rail can be rapidly reduced, and the heat of the rail web part can be rapidly conducted to the two ends, thereby reducing the residual stress of the rail web of the rail and improving the comprehensive performance of the rail web of the turnout rail.
In order to make the cooling medium spray out uniformly and quickly for the purpose of rapid cooling, the cooling medium is preferably air or mist. Because the heat quantity to be conducted by the rail webs with different thicknesses is different, the cooling rate is controlled by adjusting the pressure sprayed by the cooling medium so as to adapt to different steel rails, and the specific pressure is as follows: v is (T1-700)/60+ G/20-1.5, wherein T1 is the rail web temperature of the steel rail entering unit, and G is the thickness of the rail web.
The restraint device for carrying out on-line heat treatment on the rail web of the turnout steel rail comprises a fixed frame 1 and a cooling device 2 as shown in figures 1 and 2; the top of the fixed frame 1 is provided with a bottom restraint wheel 3, two sides of the fixed frame 1 are provided with rocker arms 4, the upper ends of the rocker arms 4 are provided with guide plates 5, the inner sides of the guide plates 5 are provided with upper restraint wheels 6, the rail bottom of the steel rail 7 is placed on the bottom restraint wheel 3, and the upper restraint wheels 6 respectively abut against two sides of the rail waist of the steel rail 7; the cooling device 2 is provided with a plurality of nozzles 8, and the nozzles 8 respectively face the center of the railhead tread, two sides of the railhead and the center of the rail bottom of the steel rail 7.
The bottom restraint wheels 3 are mainly used for bearing and conveying steel rails 7, in order to avoid the bottom restraint wheels 3 from shielding the middle of the rail bottom and influencing the cooling effect, the bottom restraint wheels 3 can be arranged on two sides of the rail bottom, and a middle part is reserved for the nozzles 8 to spray cooling media to the rail bottom. The upper restraint wheels 6 on the two sides are used for clamping the rail web, so that the steel rail 7 is limited from shaking left and right. The cooling device 2 comprises a cooling and pressurizing part and is provided with a control system for controlling the pressure of the sprayed cooling medium, including applying different pressures to different parts. A plurality of nozzles 8 for cooling the same portion may be provided at regular intervals to improve the cooling effect.
Because the thickness of the middle rail web of the turnout steel rail of different models is different, in order to enable the device to adapt to rail webs of different thicknesses, the middle part of the rocker arm 4 is hinged with the fixed frame 1, and the lower end of the rocker arm 4 is connected with the fixed frame 1 through the adjusting bolt 9. Through rotating adjusting bolt 9, can make rocking arm 4 rotate round the pin joint in middle part to two rocking arm 4 upper ends of control realize opening and shutting, in order to reach the purpose that can both press from both sides tightly the rail waist to different thickness.
Furthermore, the length of the guide plate 5 is 1-2 m, and two groups of rocker arms 4 are arranged at intervals in the length direction of the guide plate 5. According to the practical application condition, the guide plate 5 with the length of 1-2 m is arranged, namely, the guide plate passes through the cooling path with the length of 1-2 m, so that the resource utilization is more economical and reasonable while the cooling effect is ensured, and the purposes of energy conservation and environmental protection are achieved. Two sets of rocker arms 4 are arranged, so that the supporting force can be improved, and the stable operation of the steel rail 7 is ensured.
The present application is further illustrated by comparative tests.
Example (b):
the following steel rail chemical components are selected in the embodiment of the invention and the corresponding comparative example.
TABLE 1 chemical composition/% of the example Steel rails
The comparative examples in the present invention used the same chemical composition, heating, and rolling processes as those of the examples. The shape of the rolled turnout rail is 60AT1, the thickness of the rail web is 44mm, and the temperature of the rolled turnout rail entering a machine set is 760 ℃.
The method of the application is adopted to carry out different heat treatment processes and different rail web heat treatment processes (cooling speed of applied cooling medium) on the steel rail. In which 1# to 3# are constraint devices using different processes and are supplemented with different heat treatment processes, and 4# is a comparative example in which no heat treatment process is performed. Subsequently, 4 samples are produced by the same heating and rolling process,
TABLE 2 Heat treatment process for steel rails of examples and comparative examples and heat treatment restraining device used therein
And respectively detecting the tensile property, the structure and the rail bottom residual stress of 4 steel rail samples according to the requirements of TB/T2344-.
TABLE 3 examples and comparative examples test for tensile Properties, thickness of oxide layer and residual stress of rails
In the invention, the steel rails with the same chemical composition are selected for comparison, and in the embodiment, the 3 treatment modes are the method in the invention. The results of the comparison in tables 1 to 3 show that the strength and toughness of the turnout rail web are improved by adopting the heat treatment process. Meanwhile, the rail web is heated for heat treatment and cooling strength, so that a martensite structure is easy to appear in the structure, and meanwhile, an accelerated cooling and restraining device is applied to the rail web, so that the residual stress of the steel rail is obviously reduced.
In conclusion, the heat treatment production method and the heat treatment restraining device for the steel rail can obviously reduce the residual stress of the rail web of the steel rail and improve the matching property of the structure and the performance of the steel rail, thereby improving the comprehensive performance of the rail web of the turnout steel rail and having good practicability and application prospect.
Claims (2)
1. The on-line heat treatment method for the rail web of the turnout steel rail is characterized by comprising the following steps:
firstly, controlling the temperature of the steel rail at 700-800 ℃, wherein the percentage content of the carbon content is between 0.7 and 0.90 percent;
then, the steel rail is sent into a restraint device, an accelerated cooling medium is applied to the center of the tread of the rail head, two sides of the rail head and the center of the rail bottom of the steel rail by using the restraint device, the cooling medium is air blast or spray, the cooling speed is 1-5 ℃/s, and the pressure sprayed by the cooling medium is as follows: v is (T1-700)/60+ G/20-1.5, wherein T1 is the rail web temperature of the steel rail entering the unit, the unit is the temperature, and G is the thickness of the rail web, and the unit is mm;
and finally, when the temperature of the steel rail is reduced to 450-500 ℃, the steel rail is sent out of the restraint device.
2. The restraining device for implementing the on-line heat treatment method of the turnout rail web according to claim 1 is characterized in that: comprises a fixed frame (1) and a cooling device (2); the top of the fixing frame (1) is provided with a bottom restraint wheel (3), two sides of the fixing frame (1) are provided with rocker arms (4), the upper ends of the rocker arms (4) are provided with guide plates (5), the length of each guide plate (5) is 1-2 m, two groups of rocker arms (4) are arranged in the length direction of each guide plate (5) at intervals, the inner sides of the guide plates (5) are provided with upper restraint wheels (6), the rail bottoms of the steel rails (7) are placed on the bottom restraint wheels (3), and the upper restraint wheels (6) respectively abut against two sides of the rail web of the steel rails (7); the cooling device (2) is provided with a plurality of nozzles (8), the nozzles (8) respectively face the center of the tread of the rail head of the steel rail (7), two sides of the rail head and the center of the rail bottom, the middle part of the rocker arm (4) is hinged with the fixed frame (1), and the lower end of the rocker arm (4) is connected with the fixed frame (1) through an adjusting bolt (9).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811378013.7A CN109338075B (en) | 2018-11-19 | 2018-11-19 | On-line heat treatment method for rail web of turnout steel rail and restraining device thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811378013.7A CN109338075B (en) | 2018-11-19 | 2018-11-19 | On-line heat treatment method for rail web of turnout steel rail and restraining device thereof |
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|---|---|
| CN109338075A CN109338075A (en) | 2019-02-15 |
| CN109338075B true CN109338075B (en) | 2020-11-10 |
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| CN201811378013.7A Active CN109338075B (en) | 2018-11-19 | 2018-11-19 | On-line heat treatment method for rail web of turnout steel rail and restraining device thereof |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1178250A (en) * | 1996-09-29 | 1998-04-08 | 攀枝花钢铁(集团)公司 | Heat treating method and apparatus for producing high duty rails by waste heat from rolling process |
| CN1920062A (en) * | 2006-09-12 | 2007-02-28 | 攀枝花钢铁(集团)公司 | Rail heat processing method and rail heat processing unit |
| CN202226887U (en) * | 2011-09-09 | 2012-05-23 | 攀钢集团攀枝花钢铁研究院有限公司 | Guiding and restraining device for controlling running trace of railroad turnout steel rail |
-
2018
- 2018-11-19 CN CN201811378013.7A patent/CN109338075B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1178250A (en) * | 1996-09-29 | 1998-04-08 | 攀枝花钢铁(集团)公司 | Heat treating method and apparatus for producing high duty rails by waste heat from rolling process |
| CN1920062A (en) * | 2006-09-12 | 2007-02-28 | 攀枝花钢铁(集团)公司 | Rail heat processing method and rail heat processing unit |
| CN202226887U (en) * | 2011-09-09 | 2012-05-23 | 攀钢集团攀枝花钢铁研究院有限公司 | Guiding and restraining device for controlling running trace of railroad turnout steel rail |
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| CN109338075A (en) | 2019-02-15 |
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