Composite rail and rolling method

Abstract

The embodiment of the present disclosure relates to the field of rolling steel, and discloses a composite rail and a rolling method, the method comprising: machining a groove at a position corresponding to a head of a rail product of a billet; embedding a stainless steel strip matching the shape of the groove in the groove; and rolling the stainless steel strip with the billet to form a rail product with a conductive strip. The over-heated rolling composite method of the exemplary embodiment of the present disclosure is verified by a large number of tests, and the stainless steel composite rail for track conduction produced by the method has stable specifications and performance. The present application is the first of its kind in China, and has a revolutionary significance for improving and enhancing the conduction performance of the line, and has a wide market prospect.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the technical field of steel rolling, and in particular to a composite rail and a rolling method. Background Art

[0002] Rails are the channels for transmitting train operation information in track circuit systems. Rails are exposed to the elements and are subject to natural corrosion. Rust is particularly prevalent on tracks within stations where trains rarely pass. Oxides (rust) increase shunt resistance, which is the primary cause of poor track circuit shunt information. This poor track circuit shunt information within stations poses a safety hazard to train operations and warrants attention and resolution.

[0003] The more mature solution at present is to continuously weld a certain width of stainless steel on the rail tread to meet the existing track circuit branching requirements while having sufficient wear resistance. Figure 1 and Figure 2 As shown, the rails are installed above the roadbed 5. The bottom of the wheel hub 1 contacts the rail at the weld bead 2, fusion zone 3, and heat-affected zone 4. The weld bead 2 on the rail surface is a straight line and is located at the centerline of the rail surface or the inner arc. This is where the wheel flange of the wheel hub 1 is in closest contact with the rail. The weld bead dimensions are: weld bead width 10mm±2mm, fusion depth with the rail <2.5mm, and height of the weld overlay layer above the rail surface <2.5mm. However, this solution has the following disadvantages: the track overlay welding process inevitably produces residual deformation due to unbalanced heating and cooling, leading to the formation of cold cracks. At the same time, the subsequent overlay welding of the stainless steel layer wastes a lot of manpower and material resources, and the portion that protrudes above the rail surface will cause instability in train operation.

[0004] Another option is a composite casting method in which a layer of stainless steel is cast on the surface of the ingot during continuous casting. However, due to the difference in material quality between stainless steel and rail steel, and the poor fusion between stainless steel casting and rail steel casting, the composite casting method is difficult to implement.

[0005] Therefore, how to prepare a finished rail with a stainless steel strip on the surface during production while maintaining a stable structure and performance has become an urgent problem to be solved. Summary of the Invention

[0006] The embodiments of the present disclosure provide a composite rail and a rolling method to solve or alleviate one or more of the above technical problems in the prior art.

[0007] According to one aspect of the present disclosure, there is provided a composite rail rolling method, comprising:

[0008] A groove is machined in the steel billet at a position corresponding to the head of the finished rail;

[0009] Inlaying a stainless steel bar matching the shape of the groove into the groove;

[0010] Stainless steel bars and billets are rolled to form finished rails with conductive strips.

[0011] In a possible implementation, before machining the groove at the position of the steel billet corresponding to the head of the finished rail, the process includes:

[0012] The size of the groove is calculated based on the required size of the conductive tape and the theoretical elongation coefficient.

[0013] In a possible implementation, before inserting a stainless steel bar matching the shape of the groove into the groove, the method includes:

[0014] The size of the stainless steel strip can be deduced based on the required size of the conductive strip and the elongation coefficient of the finished rail head during the rolling process.

[0015] In a possible implementation, after forming a groove in the steel billet at a position corresponding to the head of the finished rail, the process includes:

[0016] The groove is pickled to remove foreign matter in the groove.

[0017] In a possible implementation, embedding a stainless steel bar matching the shape of the groove in the groove includes:

[0018] Push the stainless steel bar into the groove from the end and embed it into the groove;

[0019] The surface and ends of the grooves inlaid with stainless steel strips are sealed.

[0020] In a possible implementation, two grooves are symmetrically provided along the center line of the steel billet.

[0021] In a possible implementation, the length of the stainless steel bar is smaller than the length of the groove.

[0022] In a possible implementation, the steel billet is a casting.

[0023] In a possible implementation, the groove is an inverted T-shaped dovetail groove, and the stainless steel bar is a T-shaped steel bar that matches the inverted T-shaped dovetail groove.

[0024] According to one aspect of the present disclosure, there is provided a composite rail, which is rolled according to the above composite rail rolling method.

[0025] The exemplary embodiments disclosed herein have the following beneficial effects: The inverted "T"-shaped dovetail structure of the exemplary embodiments disclosed herein avoids the overflow and shedding of the stainless steel bars due to rolling and squeezing during the rolling process. The exemplary embodiments disclosed herein can fully guarantee the survival of the stainless steel bars during the service life of the rails, and will not cause the stainless steel bars to fall off or wear out during the rail cycle. The method for rolling stainless steel composite rails for rail conductivity effectively solves the difficult problems of complex composite casting processes and high surface welding costs for finished products. Through hot rolling composite methods, stainless steel composite rails with conductive properties can be realized in hot rolling, eliminating the thorny problem of welding residual stress deformation that inevitably occurs due to unbalanced heating and cooling during the rail welding process before going online, leading to the generation of cold cracks.

[0026] The exemplary embodiment of the present disclosure is achieved in a hot rolling process through a stainless steel composite rail rolling method, which greatly saves the cost of subsequent surfacing and processing, and the stainless steel conductor formed by one-time rolling has excellent conductive performance.

[0027] The exemplary embodiment of the present disclosure uses hot-rolling composite stainless steel rails. The hot-rolling method has been verified by a large number of tests. The specifications and performance of the stainless steel composite rails produced for track conduction are stable. This invention is a domestic first and has revolutionary significance for the enhancement and improvement of line conductivity, and has broad market promotion prospects.

[0028] The details of one or more embodiments of the present application are set forth in the following drawings and description. Other features and advantages of the present application will become apparent from the accompanying drawings. It should be understood that the above general description and the detailed description that follows are merely exemplary and explanatory and do not limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification, are used to explain the principles of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0030] Figure 1 It is a structural diagram of a steel rail in the prior art;

[0031] Figure 2 It is a schematic diagram of the structure when the rail and the steel hub are in contact in the prior art;

[0032] Figure 3 is a flow chart of a composite rail rolling method according to the present exemplary embodiment;

[0033] Figure 4is a schematic diagram of the three-dimensional structure of a steel billet inlaid with stainless steel bars according to this exemplary embodiment;

[0034] Figure 5 is a schematic diagram of a three-dimensional structure of a rail with a conductive strip according to this exemplary embodiment;

[0035] Figure 6 is a schematic structural diagram of a steel rail with a conductive strip according to an exemplary embodiment;

[0036] Figure 7 Schematic diagram of the rolling inheritance relationship between the ingot and the finished rail product in this exemplary embodiment;

[0037] Figure 8 is a front view of a steel billet inlaid with a stainless steel strip according to the exemplary embodiment;

[0038] Figure 9 is a front view of a rail with a conductive strip according to an exemplary embodiment;

[0039] Figure 10 is a schematic structural diagram of a stainless steel bar according to this exemplary embodiment;

[0040] Figure 11 FIG. 4 is a schematic structural diagram of a conductive tape according to an exemplary embodiment of the present invention.

[0041] In the figure: 1. Wheel hub; 2. Weld bead; 3. Fusion zone; 4. Heat-affected zone; 5. Roadbed; 6. Steel billet; 7. Stainless steel bar; 8. Conductive tape; 9. Rail; 10. Weld point. DETAILED DESCRIPTION

[0042] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the present disclosure will be more comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced while omitting one or more of the specific details, or that other methods, components, devices, steps, etc. may be employed. In other cases, well-known technical solutions are not shown or described in detail to avoid obscuring various aspects of the present disclosure.

[0043] In addition, the accompanying drawings are merely schematic illustrations of the present disclosure and are not necessarily drawn to scale. Identical reference numerals in the figures denote identical or similar parts, and thus repetitive descriptions thereof will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically separate entities. These functional entities may be implemented in software, in one or more hardware units or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0044] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all steps. For example, some steps may be decomposed, while some steps may be combined or partially combined, so the actual execution order may change according to actual circumstances.

[0045] The terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the application described herein can, for example, be implemented in an order other than that illustrated or described herein.

[0046] In addition, the terms "comprise" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or submodules is not necessarily limited to those steps or submodules explicitly listed, but may include other steps or submodules not explicitly listed or inherent to such process, method, product or apparatus.

[0047] Figure 3 is a flow chart of a composite rail rolling method of this exemplary embodiment, as shown in FIG. Figure 3 As shown, an exemplary embodiment of the present disclosure provides a composite rail rolling method, comprising:

[0048] S1 processes a groove in the steel billet at the position corresponding to the head of the finished rail;

[0049] S2 is a stainless steel bar inlaid in the groove with a shape matching the groove;

[0050] S3 rolls the stainless steel bars and billets to form finished rails with conductive strips.

[0051] Specifically, before machining a groove at a position of the steel billet corresponding to the head of the finished rail, the process includes:

[0052] The size of the groove is calculated based on the required size of the conductive tape and the theoretical elongation coefficient.

[0053] The present embodiment proposes a method for rolling a stainless steel composite rail for track conduction, which effectively solves the problems of complex composite casting process, high cost and low efficiency of surface welding of finished products. The hot rolling method of the stainless steel composite rail has been successfully tested after a large number of tests. The specifications of the stainless steel composite rail for track conduction produced are stable, which has revolutionary significance for the enhancement and improvement of line conductivity and has broad market promotion prospects.

[0054] For example, Figure 4 As shown, in this embodiment, an inverted T-dovetail groove is machined at the position of the steel billet 6 corresponding to the conductive strip 8 at the head of the rail 9, and a T-shaped stainless steel strip is embedded in the inverted T-dovetail groove. Through the existing rail rolling process (heating - descaling - blanking - rough rolling - finishing rolling - hot sawing - straightening), the stainless steel strip is hot-rolled and composited with the steel billet substrate, and a stainless steel conductive strip is rolled and extended on the surface of the finished product. The finished product after rolling is as shown in FIG. Figure 5 As shown, it meets the existing track circuit branching requirements. During operation, due to the stainless steel characteristics of the conductive belt, it will not rust, and at the same time has sufficient wear resistance, which can achieve long-term and stable conductive effect.

[0055] This embodiment takes the rolling method of a conductive stainless steel composite rail for producing an existing 60kg / m standard rail from a 280*380 cross-section steel billet as an example, and is described in detail with reference to the accompanying drawings, including the following steps:

[0056] (1) Billet processing: According to the rolling inheritance relationship between the billet and the finished rail (such as Figure 7 As shown, Figure 7 The left side of the figure is the ingot, and the right side is the finished rail. The av marks on the ingot represent the various positions of the ingot, which correspond one-to-one with the av marks on the finished rail. Inverted T-shaped dovetail grooves are processed at the corresponding positions of the corresponding surfaces of the ingot. The dovetail groove size is calculated based on the required conductive strip size and the theoretical elongation coefficient. The dovetail groove processing size is designed according to a certain scaling factor in the width direction of the calculated actual size to facilitate installation. The purpose of processing it into an inverted T-shaped dovetail groove is to prevent the T-shaped stainless steel bar from being squeezed out during the hot rolling process and to ensure that it is fully extended in the dovetail groove.

[0057] (2) After the inverted T dovetail groove is processed on the steel billet, a stainless steel T-bar of corresponding size is processed. The size of the stainless steel T-bar is reversed according to the required conductive strip size and the extension coefficient of the rail head during rolling. The top width, bottom width and height of the stainless steel T-bar section are calculated. The length of the stainless steel T-bar is 20-40 mm shorter than the dovetail groove.

[0058] (3) After the inverted T dovetail groove on the steel billet is processed and before the T-shaped stainless steel bar is assembled, pickling is carried out to clean the dust, oxides and other foreign matter in the dovetail groove to ensure the fit between the inverted T dovetail groove and the stainless steel bar during the rolling process.

[0059] (4) Push the processed T-shaped stainless steel bar from the end and embed it into the inverted T dovetail groove, ensuring that the fitting surface is tight and firm, leaving 10-20mm at the end for end sealing welding.

[0060] (5) After the inlay is completed, the surface and ends are sealed with stainless steel welding rods, the material of which is the same as that of the T-shaped stainless steel bars.

[0061] (6) The material of the T-shaped stainless steel bar is made of stainless steel with good ductility to ensure that it can fully extend in the dovetail groove during the rolling process and be hot-rolled with the steel billet matrix.

[0062] (7) After processing and assembly, the rails are rolled into conductive stainless steel composite rails through the existing rail rolling process (heating - descaling - blanking - rough rolling - finishing rolling - hot sawing - straightening).

[0063] If the rail needs to be replaced, the conductive strips on the rail tread can be made into two symmetrical ones with the center line of the rail head, and the production method of the other conductive strip is the same as above.

[0064] Specifically, before inserting a stainless steel bar matching the shape of the groove into the groove, the method includes:

[0065] The size of the stainless steel strip can be deduced based on the required size of the conductive strip and the elongation coefficient of the finished rail head during the rolling process.

[0066] Specifically, after the groove is machined at the position of the steel billet corresponding to the head of the finished rail, the process includes:

[0067] The groove is pickled to remove foreign matter in the groove.

[0068] Specifically, embedding a stainless steel bar matching the shape of the groove in the groove includes:

[0069] Push the stainless steel bar into the groove from the end and embed it into the groove;

[0070] The surface and end of the groove inlaid with the stainless steel strip are sealed.

[0071] Specifically, two grooves are symmetrically opened along the center line of the steel billet.

[0072] Specifically, the length of the stainless steel strip (the length of the stainless steel strip along the laying direction of the rail) is smaller than the length of the groove.

[0073] Specifically, the steel billet is a casting.

[0074] Specifically, the groove is an inverted T-shaped dovetail groove, and the stainless steel bar is a T-shaped steel bar that matches the inverted T-shaped dovetail groove.

[0075] The present embodiment proposes a method for rolling a stainless steel composite rail for conducting electricity. In this method, an inverted T-dovetail groove is machined on the two conductive strips on the steel billet corresponding to the rail head, and a T-shaped stainless steel strip is embedded in the inverted T-dovetail groove. The stainless steel and the steel billet substrate are hot-rolled and composited through the existing rail rolling process. A stainless steel conductive strip is rolled and extended on the surface of the finished product. The stainless steel conductive strip has a width of 10 mm ± 2 mm and a depth of less than 3.5 mm, which meets the existing track circuit branching requirements. During operation, due to the stainless steel characteristics of the conductive strip, it will not rust and has sufficient wear resistance, which can achieve long-term and stable conductive effect. Figure 4 、 Figure 5 and Figure 6 This embodiment illustratively includes the following steps:

[0076] Rail Conductive Strip Dimensions: On the finished rail surface, the conductive strip runs straight through, located on both sides of the rail surface center, with the center of the conductive strip 23.96mm from the centerline of the rail tread. This location is where the wheel flange and rail make the closest contact. The conductive strip dimensions are: width 10mm ± 3mm (designed to 10mm), and fusion depth with the rail less than 3.5mm (designed to 3mm).

[0077] According to the rolling inheritance relationship between the billet and the finished rail in actual production (such as Figure 7 As shown in the figure), according to the rail head elongation coefficient of 14.18, the widening coefficient of 2.22, and the compression coefficient of 7.203, the required basic dimensions of stainless steel are: width = 10mm*2.22 = 22.2mm, thickness = 3mm*7.203 = 21.61mm. Taking into account the comprehensive rolling deformation, to prevent the stainless steel from separating from the matrix during the rolling process and to meet the basic dimensional requirements of the finished stainless steel strip, it is modified into an inverted T-shaped dovetail structure. The dimensions are modified dynamically. The processing position of the T-shaped dovetail groove is set at 38mm on both sides of the center line of the billet according to the rolling inheritance relationship between the ingot and the finished rail. Figure 8 and Figure 9 , the specific dimensions of the inverted T-shaped dovetail groove and T-shaped stainless steel processing are as follows Figure 10 and Figure 11 shown.

[0078] Among them, the inverted T-shaped dovetail groove and the T-shaped stainless steel leave an installation gap allowance. The design here is based on an offset allowance of 0.1mm to ensure that the T-shaped stainless steel is smoothly installed in place and fully extended in the dovetail groove during the hot rolling process.

[0079] After the inverted T dovetail groove is processed and before the T-shaped stainless steel bar is assembled, it is pickled with a sulfuric acid aqueous solution with a concentration of 10%-20% to remove dust, oxides and other foreign matter in the dovetail groove to ensure that the inverted T dovetail groove fits tightly with the stainless steel bar during the rolling process.

[0080] The processed T-shaped stainless steel strip is pushed into the inverted T-shaped dovetail groove from the end, inlaid into the inverted T-shaped dovetail groove, to ensure that the fitting surface is tightly and firmly attached, and 20mm is left at the end for end sealing welding, and the position of the welding spot 10 is as shown in Figure 11 .

[0081] The T-shaped stainless steel strip is made of 304L stainless steel with good ductility, to ensure that the dovetail groove is fully extended and combined with the base body during rolling.

[0082] After inlaying, the surface and the end are sealed, and the sealing is made of stainless steel welding rod, which is the same as the T-shaped stainless steel strip.

[0083] After processing and assembly, the inverted T-shaped stainless steel strip is rolled and extended into a drum-shaped stainless steel strip through the existing rail rolling process (heating - descaling - blooming - rough rolling - finishing - hot sawing - straightening), the stainless steel strip is rolled and combined at the head of the rail, and the root is inlaid in the rail, which has good stability, the head and the rail tread are smoothly transitioned, and have good smoothness and conductivity.

[0084] The rolled and formed stainless steel composite rail with conductivity, as shown in Figure 6 , can be directly laid on the line.

[0085] If the rail needs to be used on the other side, the conductive strip on the rail tread can be made into two symmetrical lines with the center line of the rail head, and the other conductive strip is made in the same way.

[0086] Figure 6 is a structural diagram of the rail with a conductive strip according to the present exemplary embodiment, as shown in Figure 6 , the present exemplary embodiment provides a composite rail rolled according to the above-mentioned rolling method.

[0087] The above is only a preferred embodiment of the present disclosure, and the protection scope of the present disclosure is not limited to the above-mentioned embodiments, and any technical solution falling within the scope of the present disclosure is within the protection scope of the present disclosure. It should be noted that for ordinary skilled persons in the art, some improvements and decorations without departing from the principles of the present disclosure should be considered within the protection scope of the present disclosure.

Claims

1. A composite rail rolling method, characterized in that: include: A groove is machined in the steel billet at a position corresponding to the head of the finished rail; Inlaying a stainless steel bar matching the shape of the groove into the groove; The stainless steel strips and billets are rolled to form finished rails with conductive strips; Before the groove is machined in the steel billet at the position corresponding to the head of the finished rail, the following steps are included: Calculate the size of the groove according to the required size of the conductive tape and the theoretical elongation coefficient; Before inserting a stainless steel bar matching the shape of the groove into the groove, the method includes: The size of the stainless steel strip is deduced based on the required size of the conductive strip and the elongation coefficient of the finished rail head during rolling; After the groove is machined in the steel billet at the position corresponding to the head of the finished rail, the following steps are included: Pickling the groove to remove foreign matter in the groove; The stainless steel bar inlaid in the groove and matching the shape of the groove includes: Push the stainless steel bar into the groove from the end and embed it into the groove; Sealing the surface and ends of the grooves inlaid with stainless steel bars; Two rail conductive belts are symmetrically arranged on both sides of the center of the finished rail surface; The dimensions of the rail conductive strip, including the distance between the rail conductive strip and the centerline of the rail tread and the fusion depth between the rail conductive strip and the rail; The grooves are symmetrically provided along the center line of the steel billet. The groove is an inverted T-shaped dovetail groove, and the stainless steel bar is a T-shaped steel bar that matches the inverted T-shaped dovetail groove; The inverted T-shaped dovetail groove is used to prevent the T-shaped stainless steel bar from being squeezed out during the hot rolling process, ensuring that the T-shaped stainless steel bar is fully extended in the dovetail groove; The T-shaped steel bar is made of ductile stainless steel to ensure that it is fully extended in the dovetail groove during the rolling process and hot-rolled with the steel billet matrix; The T-shaped stainless steel strip is rolled and extended into a drum-shaped stainless steel strip, which is rolled and laminated on the rail head. The root of the stainless steel strip is embedded in the rail, and the stainless steel strip head and the rail tread have a smooth transition.

2. The composite rail rolling method according to claim 1, characterized in that: The length of the stainless steel bar is smaller than the length of the groove.

3. The composite rail rolling method according to claim 1, characterized in that: The steel billet is a casting.

4. A composite rail, characterized in that: The composite rail is rolled according to the composite rail rolling method according to any one of claims 1 to 3.

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