阅读说明：本技术 一种钢轨跟端加热装置 (Steel rail heel end heating device ) 是由 杨含 施庆峰 亓云飞 兰超锋 武振甲 于 2021-09-01 设计创作，主要内容包括：本发明公开了一种钢轨跟端加热装置,该加热装置用于降低钢轨压型跟端热影响区的长度,具体包括：感应加热炉,所述感应加热炉的炉口内设有感应加热线圈,所述感应加热线圈自内向外逐渐加密排列,且所述感应加热线圈与感应加热机电连接。本发明是在不改变原有感应加热炉的基础上,通过在炉口处上炉壁加装一定长度的仿形中频感应加热线圈,在低功率、短时间工作状态下,保证线圈下钢轨跟端纵向加热温度与炉内温度偏差不超过±50℃。最终,缩短了钢轨跟端加热过程中热影响区软区长度,减少了软点数量,提升钢轨的使用寿命和过车的平顺性。(The invention discloses a heating device for a steel rail heel, which is used for reducing the length of a heat affected zone of the profiled steel rail heel and specifically comprises the following components: the induction heating furnace is characterized in that an induction heating coil is arranged in a furnace mouth of the induction heating furnace, the induction heating coil is gradually arranged in an encrypted manner from inside to outside, and the induction heating coil is electrically connected with the induction heating machine. On the basis of not changing the original induction heating furnace, the invention ensures that the longitudinal heating temperature of the heel end of the steel rail under the coil does not exceed +/-50 ℃ from the temperature in the furnace under the working state of low power and short time by additionally arranging the profiling medium-frequency induction heating coil with a certain length on the upper furnace wall at the furnace mouth. Finally, the length of a soft area in a heat affected zone in the heating process of the heel end of the steel rail is shortened, the number of soft points is reduced, the service life of the steel rail is prolonged, and the smoothness of vehicle passing is improved.)

1. A rail heel end heating device, comprising: the induction heating furnace is characterized in that an induction heating coil is arranged in a furnace mouth of the induction heating furnace, the induction heating coil is gradually arranged in an encrypted manner from inside to outside, and the induction heating coil is electrically connected with the induction heating machine.

2. The device as claimed in claim 1, wherein the induction heating coil is made by winding a copper tube, and the copper tube is filled with cooling water.

3. A rail heel end heating device according to claim 2, wherein the induction heating coil is of a "gate" configuration in cross-section and spans the top of the rail heel end to be heated.

4. A rail heel end heating device according to claim 2, wherein the induction heating coil is of annular configuration in cross-section and surrounds the periphery of the heel end of the rail to be heated.

5. A rail heel end heating device according to claim 3 or 4, wherein one end of the induction heating coil is flush with the mouth of the induction heating furnace and the other end extends into the induction heating furnace by no more than 200 mm.

6. A rail heel end heating device according to claim 5, wherein the distance between the induction heating coil and the top of the rail heel end to be heated is 8-15 mm.

Technical Field

The invention belongs to the technical field of heat treatment of turnout steel rail pieces, and particularly relates to a steel rail heel heating device.

Background

After the turnout switch rail heel end is molded, in order to ensure that the overall quality of the molded section meets the requirement of the original base metal, the molded heating section needs to be thermally treated again. There are two main ways of heat treatment: one is that the forged steel rail heel is directly heated in an induction heating furnace in a full section at 900-1000 ℃, and then is quickly pushed to a wind box to spray wind on the rail top for cooling; the other method is that the heel end is firstly normalized in a resistance furnace, after air cooling to room temperature, the steel rail is moved on a quenching machine tool, and the rail head part of the heel end of the steel rail is continuously heated and cooled by air injection.

The first mode has high production efficiency and good overall performance of the heel end after heat treatment, but due to the factors of long heating time, low heating efficiency caused by self heat dissipation of the steel rail and magnetic field divergence of the end of the inductor and the like, a soft area (an area with the hardness of the rail top surface of the steel rail lower than the minimum hardness required by the base metal) with a certain length exists in a heat affected area of heat treatment heating. The second heat treatment mode has large gradient change of the hardness of the section of the steel rail, low production efficiency and higher turnout manufacturing cost than the first heat treatment mode. Before the industry standard of 2019 is implemented, the length of a soft area of a heat affected zone is not particularly required, both modes are used, and then the number of soft points is specified to be not more than 5 points (the surface hardness points are separated by 10 mm). Through a plurality of process verification tests, after the heat treatment by using the first induction furnace heating mode, the number of soft points is more than 5, the soft points are all arranged in the furnace mouth for a certain distance, and the second mode can meet the standard requirement.

If the hardness of the soft zone formed during heating is low, the range is long, and diseases such as fat edge, saddle-shaped abrasion and even crushing are caused during vehicle passing. This is detrimental to line maintenance, ride comfort and safety.

Therefore, the heating mode of the furnace mouth of the existing induction heating furnace needs to be improved, the length of a heat affected zone is shortened, and the problem of steel rail diseases in the driving process is solved.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a heating device for a heel end of a steel rail. The technical problem to be solved by the invention is realized by the following technical scheme:

a rail heel heating apparatus comprising: the induction heating furnace is characterized in that an induction heating coil is arranged in a furnace mouth of the induction heating furnace, the induction heating coil is gradually arranged in an encrypted manner from inside to outside, and the induction heating coil is electrically connected with the induction heating machine.

Furthermore, the induction heating coil is formed by winding a copper pipe, and cooling water is introduced into the copper pipe.

Furthermore, the section of the induction heating coil is of a door-shaped structure and spans above the top of the heel end of the steel rail to be heated.

Furthermore, the cross section of the induction heating coil is of an annular structure and surrounds the periphery of the heel end of the steel rail to be heated.

Further, one end of the induction heating coil is flush with the furnace mouth of the induction heating furnace, and the other end of the induction heating coil extends into the induction heating furnace for no more than 200 mm.

Further, the distance between the induction heating coil and the top of the steel rail heel to be heated is 8-15 mm.

The invention has the beneficial effects that:

1. on the basis of not changing the original induction heating furnace, the invention ensures that the deviation between the longitudinal heating temperature of the steel rail under the coil and the temperature in the furnace does not exceed +/-50 ℃ under the working state of low power and short time by additionally arranging the profiling medium-frequency induction heating coil with a certain length on the upper furnace wall at the furnace mouth. Finally, the length of a soft area in a heat affected zone in the heating process of the steel rail is shortened, the number of soft points is reduced, the service life of the steel rail is prolonged, and the smoothness of passing is improved;

2. the device has simple structure, easy manufacture, small investment and simple maintenance.

The present invention will be described in further detail with reference to the accompanying drawings and examples.

Drawings

FIG. 1 is a schematic view of a structure of an induction heating coil;

FIG. 2 is a cross-sectional view of an induction heating gasket;

fig. 3 is a schematic structural diagram of a heating device for the heel end of the steel rail.

Description of reference numerals:

1-induction heating furnace; 2-induction heating coil; 3-an induction heating machine; 4-rail heel.

Detailed Description

The present invention will be described in further detail with reference to specific examples, but the embodiments of the present invention are not limited thereto.

The embodiment of the invention provides a steel rail heel end heating device, which is used for reducing the length of a heat affected zone of a profiled steel rail heel end and specifically comprises the following steps: the induction heating furnace comprises an induction heating furnace 1, wherein an induction heating coil 2 is arranged in a furnace mouth of the induction heating furnace 1, the induction heating coil 2 is gradually arranged from inside to outside in an encrypted manner, and the induction heating coil 2 is electrically connected with an induction heating machine 3.

The induction heating coil 2 is wound by a square copper tube with the size of 12 multiplied by 2mm, the shape of the induction heating coil is shown in figure 1, a circulating cooling water channel is formed inside the copper tube, and cooling water is introduced; when the heating device is in use, the cooling water is circulated through the circulating cooling water passage inside the induction heating coil 2, and the service life of the induction heating coil 2 is prolonged.

Further, 2 one end of induction heating coil flushes with the fire door tip of induction heating furnace 1, and the other end does not exceed 200mm in extending to induction heating furnace 1, and this induction heating coil 2's position is adjustable, and the distance between the rail top of induction heating coil 2 and the rail heel end 4 of treating the heating is 8 ~ 15mm when guaranteeing to heat.

Specifically, the induction heating coil 2 may be fixed at the mouth end of the induction heating furnace by an adjustable bolt, so that the distance between it and the rail top of the rail heel end 4 may be conveniently adjusted.

In order to improve the heating effect, the section of the induction heating coil 2 is of a door-shaped structure and spans over the top of the heel end 4 of the steel rail to be heated.

In addition, if the performance of the rail web and the rail bottom is required in addition to the rail top, the cross section of the induction heating coil 2 is made into a ring structure, the ring structure is similar to the cross section of the rail heel end 4, and surrounds the periphery of the rail heel end 4 to be heated, so as to meet the corresponding performance requirement, and the specific distance between the rail web and the rail bottom and the induction heating coil 2 is set according to the specific performance requirement, and the embodiment of the invention is not particularly limited herein.

In addition, considering that the longitudinal temperature gradient formed when the induction heating furnace 1 is heated is arranged at the rail heel end 4 at the furnace mouth, the induction heating coils 2 are gradually arranged and encrypted from the inside of the furnace chamber to the outside of the furnace mouth, namely, the turns of the induction heating coils 2 in unit distance are gradually increased from the inside of the furnace chamber to the outside of the furnace mouth, so that the temperature complementation is formed, and the aim of jointly increasing the temperature is fulfilled.

The power supply power of the medium-frequency induction heating machine 3 is not more than 50KW, the longitudinal heating temperature of the steel rail heel end 4 contained in the induction heating coil 2 and the temperature deviation in the induction heating furnace 1 are not more than +/-50 ℃, and overheating and even overburning of a heating area below the induction heating coil 2 are avoided.

The method for reducing the length of the heat affected zone of the heel end of the steel rail by using the heating device comprises the following steps:

s1: the heel end of the steel rail is sent into an induction heating furnace, after the preset length is reached, the induction heating furnace starts to work, and meanwhile circulating cooling water is continuously introduced into a copper pipe of the induction heating coil; the heating target temperature of the steel rail heel is 900-950 ℃.

S2: when the temperature of the heel end of the steel rail in the middle of the furnace reaches a certain temperature measured by an infrared thermometer, the temperature is generally 50 ℃ lower than the target temperature, and the induction heating coil at the furnace mouth starts to work in a low-power state of not more than 50 KW.

S3: when the temperature of the steel rail heel end of the induction heating coil heating area reaches the target temperature, the induction heating furnace and the induction heating coil stop working, at the moment, the steel rail is automatically discharged from the induction heating furnace and cooled, and the whole heating process of the steel rail heel end is completed.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.