WO2018147755A1

WO2018147755A1 - Method for producing and heat treating rail strings and facility for the implementation thereof

Info

Publication number: WO2018147755A1
Application number: PCT/RU2017/000059
Authority: WO
Inventors: Сергей Васильевич ХЛЫСТ; Алексей Геннадьевич ИВАНОВ; Михаил Николаевич КИРИЧЕНКО; Владимир Михайлович КУЗЬМИЧЕНКО; Илья Сергеевич ХЛЫСТ; Андрей Николаевич ШЕСТАКОВ; Сергей Михайлович СЕРГЕЕВ; Павел Александрович ПШЕНИЧНИКОВ
Priority date: 2017-02-07
Filing date: 2017-02-07
Publication date: 2018-08-16
Also published as: EA036937B1; EA201900231A1; RU2681046C1

Abstract

The invention relates to railway transportation and is used for producing and subsequently heat treating welded rail strings. A method for producing and heat treating rail strings comprises producing rail strings, which includes consecutively butt welding rails, removing burrs and grinding the contour of the welded joints, straightening the welded joints and checking the quality of the welded joints, and then heat treating the rail strings, which includes differentially heating elements of the rail string profile, and differentially cooling elements of the rail string profile. Heat treatment is commenced once production of the entire rail string has been completed,i.e. production and heat treatment operations are not carried out simultaneously on a rail string. The method is carried out using a facility for producing and heat treating rail strings, which comprises rail string production units and assemblies including, arranged in sequence, a welding assembly, a burr remover, a weld joint contour grinding unit, a weld joint straightening unit, and instruments for checking the quality of the welded joints, and also an arrangement for heat treating a fully produced rail string, disposed independently of the rail string production units and assemblies, in which devices for heating and cooling elements of the rail string profile are respectively capable of uniformly heating and cooling each cross section of a rail string.

Description

A method of manufacturing and heat treatment of rail lashes and a complex for implementing the method

The invention relates to railway transport and can be used for the manufacture of welded rail lashes and their subsequent heat treatment. Higher demands are placed on the quality of rail lashes due to an increase in axle load and an increase in the speed of rolling stock.

Known methods of heat treatment of welded rails:

“Method of heat treatment of welded rails” according to patent jVs 1735392 (publ. 05.23.1992), “Method of heat treatment of welded products” according to patent JVs 373318 (publ. 01.01.1973), “Method and device for heat treatment of rail joint” according to JNb 2411295 (publ. 02/10/2011 1), “Method for cooling the rail welding zone” according to patent J e 2485187 (publ. 20.06.2013), JP2008274745 (A) publ. 13.1 1. 2008, JP2008274744 (A) publ. 11/13. 2008 and JP2007175707 (A) publ. 07/12/2007. The main disadvantage of these methods is that the heat treatment of the rail lash is carried out only in limited areas - in the field of welded joints. When each region of the welded joint is heated to the temperature of the onset of phase transformations, heat affected zones are formed on both sides of the heated section, which have reduced hardness, including the hardness of the rolling surface of the rail head. This leads to uneven wear of rail lashes and their failure due to wear and formation of defects in places of reduced hardness on both sides of each area of the welded joint.

A known method of heat treatment of welded joints of a rail whip according to patent N ° 2309185 (publ. 27.10.2007). The method includes heating the rail whip in the welded area to the temperature of the onset of phase transformations in the metal, moreover, the head is heated to the width of the heat-affected zone of welding, and the sole is heated to a width several times greater than the heat-affected zone of welding, as well as subsequent hardening of the head by forced cooling while cooling the neck and sole in air. The main disadvantage of the above methods persists in this method.

For the closest analogue, JVs 2521071 (publ. 06/27/2014) “Rail welding and heat treatment complex for the manufacture of rail lashes” was selected. A method for manufacturing rail lashes according to the patent includes sequentially butt welding of non-hardened rails, removal of the weld, grinding of the contour of the welded joints and sequential hardening of the rail along the entire length by passing the welded part of the rail lash through the quenching unit. The work of the rail welding and heat treatment complex is organized as sequential along the length of the welded rail whip and the simultaneous execution of all operations: welding of rails, removal of burrs, grinding of the contour of welded joints and hardening. The first rail is introduced at one end into the conveyor-pusher, which moves the first rail and subsequent rails of the extending rail lash sequentially through all nodes and assemblies of the rail welding and heat treatment complex. Moreover, all the nodes and assemblies of the complex, including the quenching unit, are placed along the whip in a common building.

The main disadvantage of the closest analogue is the simultaneous execution of all operations of the method along the length of the same rail lash. For example, butt welding of rails of one part of a rail lash is performed during hardening of another part of it. Based on the requirements of the technology, the rails must be warmed up before welding, and this process together with welding takes several minutes. Similarly, the process of removing the burr and grinding the contour of the welded joints requires a certain time. That is, the rail lash moves intermittently, in a torn mode. Quenching with such intermittent movement is not possible. The slightest violation of the hardening regime leads to the marriage of the welded part of the rail lash, and therefore the entire lash.

Another disadvantage is that during hardening, the rail is heated only from its lateral sides, and only the rail head is cooled (see the location of the inductors pos. 14 and nozzles pos. 15 in Fig. 3 of the patent closest analogue), which leads to deformation of the rail, in particular, to its bend, to the extent that the rail does not pass through the quenching unit. In addition, with such cooling, large tensile residual stresses are formed in the rail head, which negatively affects the wear resistance of the rail during operation. A further drawback is the lack of quality control of the rail lash before hardening, which, in the case of defects in previous hardening operations, will inevitably lead to defects during hardening and economic losses.

A further disadvantage is that in the case of the manufacture of a rail whip from previously hardened rails, only small sections of the rail on both sides of each welded joint are subjected to heat treatment. It is known that for recrystallization of a weld, i.e. restoration of the hardness of the rail, heating to relatively high temperatures is necessary. As a result of such heating, heat affected zones with reduced hardness, including the hardness of the rolling surface of the rail head, are formed on both sides of the heated sections. This ultimately leads to failure of the rail lashes due to wear and tear in the heat affected zones on both sides of each welded joint.

The technical task of the proposed invention is to create a method for the production of welded rail lashes of guaranteed high quality.

The problem is solved in that the method of manufacturing and heat treatment of rail lashes, as the closest analogue, comprises manufacturing a rail lash, including sequentially butt welding of the rails, removal of the burr and grinding of the contour of the welded joints, and then heat treatment of the rail whip, including heating and cooling.

Unlike the closest analogue, the manufacture of a rail whip is completed by quality control of the welded joints, before which the editing of the welded joints is carried out; heat treatment begins after the completion of the entire rail lash, i.e. simultaneous manufacturing and heat treatment operations on one rail lash is excluded; during heat treatment, differentiated heating of the rail lash profile elements and differential cooling of the rail lash profile elements are carried out.

The technical problem was solved at a complex for the manufacture and heat treatment of rail lashes, containing units and assemblies for manufacturing a rail lash, including a sequentially located welding unit, a puller and a grinding unit for the contour of welded joints, as well as a heat treatment unit containing heating devices and cooling devices. At the same time, assemblies and assemblies for manufacturing a rail whip additionally include sequentially located after a grinding unit for a contour of welded joints, a straightening unit for welds and quality control devices for welded joints, as well as a heat treatment unit for a fully manufactured rail whip, is located independently of the assemblies and assemblies for manufacturing a rail whip, heating devices and cooling devices for rail lash profile elements have the possibility of uniformly heating and cooling each cross respectively cross section of the rail lash. The invention is illustrated by: figure 1 - a simplified layout of the nodes and assemblies for the manufacture of rail lashes; figure 2 - installation of heat treatment of the rail lash; Fig.3 - the location of the heating devices, section B - B in figure 2; figure 4 - the location of the cooling devices, section C - C in figure 2.

FIG. 1 illustrates the manufacture of the rail lash 1 when passing sequentially through the unit for preparing the ends of the rails for welding 2, the welding unit 3, the puller 4, the grinding unit for the contour of the welded joints 5, the editing unit for the welded joints 6. After the editing unit for the welded joints 6, quality control devices for welded joints are installed rail whip non-destructive methods (not shown in Fig.). The direction of movement of the stacked rail lash 1 is in the direction of arrow A. The movement of the rail lash 1 through all nodes and assemblies for the manufacture of the rail lash is performed by the first transport means 7.

In FIG. 2 schematically illustrates a heat treatment unit 8 of a rail lash 1 with heating devices 9 and cooling devices installed sequentially along the rail lash 1. The heat treatment unit 8 includes automated control devices (not shown) of the heating devices 9 and cooling devices 10 elements of the profile of the rails of the whip. Heating devices 9 of the neck of the rail may be absent. The movement of the rail lash 1 through the heat treatment unit 8 is carried out by the second conveying means 1 1 in the direction of arrow D. The first and second conveying means 7 and I (FIGS. 1, 2) can be any known mechanisms. For example, such as a drive trolley for basing a rail whip on it, or rollers 7a and 1 1a equipped with drives. The drive rollers 11a in the heat treatment unit 8 (Fig. 2) can be installed between the heating devices 9, between the paired heating device 9 and the cooling device 10, and between the cooling devices 10. The drive rollers 7a (Fig. 1) can be installed in between units and assemblies 2, 3, 4, 5, 6 of the manufacture of rail whip 1 with the provision of transportation of the rail whip along the quality control devices of welded joints

The implementation of the method according to the proposed invention will be considered on the example of the manufacture and heat treatment of rail lashes from previously hardened and / or non-hardened rails of type P65 according to GOST R 51685-2000, as well as from old-time rails.

In the site for preparing the ends of the rails for welding 1 (Fig. 1), the previously stripped ends of the rails are tightly joined and transverse cutting is performed (perpendicular to the longitudinal axis) at the junction of the rails with a cutting mechanism, which ensures parallel joints in welding and improves the strength of the welded joint. The movement of the rails is stopped for 30 s. In addition, before welding, they can edit the rails, in the case of the straightness of these rails.

Then, in the welding unit 2, the rails are heated at the junction and welded. Butt welding is carried out by any known method, for example, reflow, induction-press welding, gas-press welding, closed arc welding, etc. A control section of the rail can be welded to the end of the rail lash. After welding, the burr is removed in the stripper 3. For the duration of these operations, equal to about 240 s, the movement of the rails is stopped.

Next, in node 4, grinding of the contour of the welded joints is performed, in which the movement of the rails is stopped for a time equal to about 60 s. Next, in the editing unit of the welded joints 5, make editing of the welded joints on the correct press or other mechanism. Moving rails when editing joints can be carried out both in the direction of arrow A, and in the opposite direction. Next, quality control of welded joints is carried out using non-destructive testing devices. For the duration of the control, the rail lash can be stopped, while the quality control of one welded joint is about 120 s.

Thus, the movement of the rail lash 1 during its manufacture is carried out with stops of various durations, for high-quality performance of technological operations of manufacturing.

Next, heat treatment of the completely manufactured rail lash 1 is carried out at the heat treatment unit 8 (Fig. 2), which is located and used independently of the equipment for manufacturing the rail lash, which makes it possible to move the rail lash with a stable speed through the heat treatment installation.

Heat treatment is carried out by methods known from the patents of the patent holder of LLC NLP TEK: RU 2487177, RU 2484148, RU 2456352 and RU 2607882. These methods can significantly improve the quality of the rails. Thus, in patent RU 2484148, differentiated heating of rail profile elements to the temperature of the onset of phase transformations in metal and differential cooling of rail profile elements during hardening of the rail are disclosed. Differential cooling of rail profile elements is carried out by adjusting the parameters of the cooling medium, in particular, changing the cooling ability of the air-water mixture, changing the pressure and air flow. In this case, the cooling intensity is controlled by changing the cooling speed of the rail at various stages of the cooling mode and in a wide range, with the ability to control the parameters of the cooling medium supplied simultaneously to various elements of the rail profile (head, neck, sole), depending on the cooling mode specified for each separate cooling device. After cooling of the rail is completed, self-tempering is performed to relieve stresses, then additional differential cooling of the rail to a temperature of <250 ° C and final cooling to a temperature below 60 ° C are carried out.

RU 2456352 discloses a method for heat treatment of rails, including continuous cooling of the rail head and sole simultaneously from rolling and / or reheating from a temperature not lower than the austenization temperature of the air with regulation of its humidity and pressure, by injecting water into the air flow to ensure a change in cooling abilities of the environment.

Also, heat treatment of the rail whip 1 can be carried out: either by high-temperature tempering, in order to temper the welded joints to reduce their brittleness and relieve stresses, or by normalizing with recrystallization of the weld to reduce brittleness and restore the hardness of the rail. In FIG. 3 shows the location of the heating elements 9 operating in predetermined heating modes for differentially heating the profile elements of the rail lash 1 in order to uniformly heat each of its cross sections to ensure minimum thermal stresses and deformations of the rail lash during heating. Because the head 12 and the sole 13 have a different mass and configuration, then they are heated at different speeds, and the sole 13 is heated according to a certain law in accordance with the heating mode of the head 12 in order to avoid warping of the rail lash 1. Heating can be performed by any type of heaters providing the required heating temperature, for example, by induction, or electric, or gas, or convective heaters. Figure 4 shows the differential cooling of the head and sole of the rail lash 1 with a cooling medium having an adjustable cooling capacity. In the cooling devices 10, a cooling medium is formed, which flows through the water pipelines 14 and the gas pipelines 15, by injecting water into the gas stream, with the possibility of controlling the parameters of the cooling medium depending on the cooling mode specified for each individual cooling device 10, with the necessary cooling rate . In FIG. 4 shows an embodiment of the base of the rail lash sole 1 on a drive carriage 1 lb.

The cooling medium may be a water-air mixture, or an aqueous medium, or an air medium with regulation of its humidity and pressure, obtained by injecting water into a stream of air. In addition, the cooling medium may be a polymer, salt-containing and / or any other cooling medium.

Differential cooling of the rail lash profile elements is carried out to a temperature providing a highly dispersed pearlite structure.

After differential cooling of the rail lash profile elements, the rail lash is self-released to relieve stresses. After self-tempering, additional differential cooling of the rail lash is carried out to a temperature of <250 ° C, which eliminates thermal warping and subsequent dressing in a roller straightening machine. After additional differential cooling, the final rail is forcedly cooled to a temperature below 60 ° C, which avoids the long exposure time of the rail lash on the refrigerator and leads to the rational use of production facilities and areas.

As a result of heat treatment receive:

- homogeneous finely dispersed pearlite structure to a depth of more than 22 mm from the head rolling surface due to the intensification of the cooling ability of the medium during cooling; - increase the plastic and strength properties of heat-treated steel by increasing the dispersion of perlite;

- the required calcination depth, dispersion of the structure and physico-mechanical properties, due to the fact that the heat treatment unit 8 is equipped with an automated control system for controlling each heating device 9, as well as for controlling and regulating the parameters of the cooling medium of each cooling device 10.

After heat treatment, the rail lash is monitored by non-destructive methods, for example, hardness and straightness. And also after heat treatment, a section of the control section of the rail with a welded joint is carried out, if any, to check the control section and the welded joint using destructive testing methods.

The heat treatment of rail lashes made by butt welding of previously hardened and / or non-hardened rails, as well as by butt welding of old-time rails, allows to obtain a homogeneous structure and properties of rail lashes along their entire length.

The fact that the heat treatment of each rail lash begins after completion of its manufacture, i.e. the simultaneous manufacture and heat treatment operations on one rail lash is excluded, it allows the manufacturing to manipulate the expandable rail lash without affecting the heat treatment operations. The result is continuous movement of the rail lash with a stable speed through the heat treatment unit 8, which is necessary in the heat treatment process and allows to obtain high quality heat-treated rail lash.

Carrying out heating of the rail whip profile elements differentially, with the possibility of operation of each heating device 9 in a predetermined heating mode, as well as conducting cooling of the rail whip profile elements differentially, with the possibility of working in 10 modes set for each individual cooling device, allow for uniform heating and cooling each cross section of the rail lash. The result is a favorable diagram of the internal residual stresses of the rail lash and its straightness.

Thus, using the proposed method, it is possible to produce rail lashes of guaranteed high quality, having throughout them an improved microstructure and a favorable diagram of the distribution of internal residual stresses, which ensures high strength and wear resistance of rail lashes and a high service life.

Claims

Claim

1. A method of manufacturing and heat treatment of rail lashes, comprising manufacturing a rail lash, including sequentially butt welding of rails, removing the grit and grinding the contour of the welded joints, and then heat treating the rail lash, including heating and cooling, characterized in that the manufacture of the rail lash is completed by quality control of the welded joints before which editing of welded joints is carried out; heat treatment begins after the completion of the entire rail lash, i.e. simultaneous manufacturing and heat treatment operations on one rail lash is excluded; during heat treatment, differentiated heating of the rail lash profile elements and differential cooling of the rail lash profile elements are carried out.

2. The method according to claim 1, characterized in that before welding the ends of the rails are tightly joined and transverse trimming is performed at the junction of the rails.

3. The method according to claim 1, characterized in that the heat treatment of the rail lash made by butt welding of hardened and / or non-hardened rails, as well as by butt welding of old-fashioned rails, is performed along the entire length of the rail lash.

4. The method according to claim 1, characterized in that the differential cooling is carried out by a medium providing the necessary cooling rate.

5. The method according to p. 4, characterized in that the differential cooling of the profile elements of the rail lash is carried out by air with the regulation of its humidity and pressure, by injecting water into the air flow.

6. The method according to p. 4, characterized in that the differentiated cooling of the rail lash profile elements is carried out with a water-air mixture, or with an aqueous medium, or with a polymer medium, or with a salt-containing medium.

7. The method according to claim 1, characterized in that the differentiated cooling of the rail lash profile elements is carried out to a temperature providing a highly dispersed pearlite structure.

8. The method according to claim 1, characterized in that the heat treatment of rail lashes can be carried out by hardening, or by high-temperature tempering, or by normalization.

9. A complex for the manufacture and heat treatment of rail lashes, containing nodes and assemblies for the manufacture of rail lashes, including sequentially located welding unit, filler and grinding unit for welding joints, as well as a heat treatment unit containing heating devices and cooling devices, characterized in that the assemblies and assemblies for manufacturing the rail lash additionally include welded joints editing unit and weld joints quality control devices sequentially located after grinding the welded joints contour , as well as the heat treatment installation of a fully fabricated rail whip, is located independently of the nodes and assemblies for manufacturing the rail whip, on revatelnye devices and elements of the cooling device runner rail profile respectively have the possibility of uniform heating and cooling of the rail cross section of each runner.

10. The complex according to claim 9, characterized in that after the dressing unit of the welded joints there are non-destructive quality control devices for the welded joints.

1 1. The complex according to claim 9, characterized in that it contains the first transporting means for moving the rail lash through all nodes and assemblies for manufacturing the rail lash.

12. The complex according to claim 9, characterized in that it contains a second conveying means for moving a fully manufactured rail whip through the heat treatment unit.

13. The complex according to claim 9, characterized in that the heat treatment unit is equipped with an automated control system for controlling each heating device, as well as for controlling and regulating the parameters of the cooling medium of each cooling device.