Roll forging method for frog rail

Abstract

A method for roll forging a frog rail is provided. A rectangular cross-section blank is heated before forging using a continuous induction heating furnace. A forging manipulator clamps one end of the blank and roll-forges the other end of the blank on a hydraulic roll forging machine to form a rail tip. The blank is turned around, and the forging manipulator clamps the rail tip-forming end of the blank and roll-forges the other end of the blank on a hydraulic roll forging machine to form a rail waist and a rail tail. The present invention solves the current technical problem of frog rails being unable to achieve large-scale, low-cost production. The present invention achieves high dimensional accuracy, low production costs, and a reduced number of process steps. Different rail shapes can be formed in one heat. The invention avoids bending and twisting problems, eliminates the need for straightening processes, and achieves good straightness, approaching the effect of closed-die forging. The process is simple and highly efficient.

Description

Technical Field

[0001] The invention belongs to the technical field of manufacturing operating transport railway turnout forgings, and in particular relates to a frog point rail roll forging method. Background Art

[0002] Currently, demand for alloy steel frog products is increasing annually in the national railway, subway, and heavy-haul railway turnout markets. All alloy steel frog products, regardless of their structure and rail type, require at least one forged alloy steel frog point rail. Fixed railway alloy steel frog point rails are large, long-axis forgings weighing 300-500 kg and measuring 2-3 meters in length. They are categorized by rail type into three series: 50, 60, and 75. These are further categorized by turnout number, such as 6, 9, 12, and 18. As can be seen, the dimensions of each forging vary, making die forging development uneconomical.

[0003] Under existing technology, various manufacturers generally use free forging processes to produce forging billets. One process involves forging or rolling rectangular cross-section billets on large precision forging machines or rolling production lines, and then directly processing the heart rail. However, this process has the disadvantages of large machining allowances for forgings and high material costs. Another process uses free forging equipment such as fast forging machines and electro-hydraulic hammers to forge the membrane based on rectangular cross-section billets, further forming a smaller machining allowance. However, this process has the problem of multiple heating cycles and low production efficiency. It can be seen that the existing heart rail processing methods impose certain restrictions on the large-scale, low-cost production of switch heart rails. In response to this, the following improved technical solutions are proposed. Summary of the Invention

[0004] The technical problem solved by the present invention is to provide a frog rail roll forging method, which adopts a rectangular cross-section billet and heats it before forging in a continuous through-type induction heating furnace; a forging manipulator clamps one end of the billet and roll-forges the other end of the billet on a hydraulic roll forging machine to form the tip of the heart rail; the billet is turned around, the forging manipulator clamps the formed end of the heart rail tip, and roll-forges the other end of the billet on the hydraulic roll forging machine to form the waist and tail of the heart rail, thereby solving the technical problem that frog rails cannot be produced in large quantities and at low cost at present.

[0005] The technical solution adopted by the present invention is a frog rail roll forging method, which comprises the following steps: heating a rectangular cross-section blank in a continuous through-type induction heating furnace before forging; clamping one end of the blank by a forging manipulator, and roll-forging the other end of the blank on a hydraulic roll forging machine to form a rail tip; turning the blank, clamping the rail tip forming end of the blank by the forging manipulator, and roll-forging the other end of the blank on the hydraulic roll forging machine in sequence to form a rail waist and a rail tail.

[0006] The above technical solution further comprises the following steps:

[0007] S1. Initial rolling of the mandrel with gradually thickened tip: The rectangular cross-section billet heated before forging in a continuous through-type induction heating furnace is conveyed from left to right between the upper and lower rollers of the hydraulic roll forging machine. The upper and lower rollers of the hydraulic roll forging machine rotate counterclockwise synchronously and gradually open and press. Under the action of friction, the billet moves from left to right and gradually separates from the upper and lower rollers, and the mandrel with gradually thickened tip is formed by initial roll forging.

[0008] S2. Forming the gradually thickened tip of the core rail: Repeat step S1 multiple times, and perform multiple roll forging to form the gradually thickened tip of the core rail.

[0009] S3, turn the center track.

[0010] S4. Forming the tapered waist of the heart rail: The turned heart rail is conveyed from right to left between the upper and lower rollers of the hydraulic roll forging machine. When it is 60 to 80 mm away from the thickest position of the gradually thickening tip of the heart rail, the upper and lower rollers of the hydraulic roll forging machine rotate clockwise synchronously and press in the same distance to form the tapered waist of the heart rail. After the tapered waist of the heart rail is formed, the upper and lower rollers rotate clockwise synchronously to move away from the heart rail. Under the action of friction, the heart rail separates from the upper and lower rollers.

[0011] S5. Forming the tapered waist of the heart rail: The heart rail is conveyed from left to right between the upper and lower rollers of the hydraulic roll forging machine, and is bitten into the heart rail with the thinnest end of the tapered waist as the starting point. The upper and lower rollers rotate counterclockwise synchronously and press down the same distance synchronously to form the tapered waist of the heart rail. After the tapered waist of the heart rail is formed, the upper and lower rollers move away from the heart rail synchronously, and the heart rail is separated from the upper and lower rollers under the action of friction.

[0012] S6. Forming the gradually thickening tail of the heart rail: The heart rail is conveyed from left to right, and the thinnest end of the gradually tapering waist of the heart rail is used as the starting point for biting. The upper and lower rollers rotate counterclockwise synchronously and gradually open and press synchronously. Under the action of friction, the blank moves from left to right and gradually separates from the upper and lower rollers, and the gradually thickening tail of the heart rail is formed by roller forging.

[0013] In the above technical solution, further: the upper and lower rollers are both flat rollers; the diameters of the upper and lower rollers are 300 to 500 mm.

[0014] In the above technical solution, further: in step S1 and step S2, the synchronous pressing distance of the upper and lower rollers is 3 to 5 mm; the pressing speed of the upper and lower rollers is 0 to 10 mm / s; the rotation speed of the upper and lower rollers is 8 revolutions / minute; the slope of the gradually thickening tip of the center rail is 1:57 to 96.

[0015] In the above technical solution, further: in step S4, the synchronous pressing distance of the upper and lower rollers is 5 to 8 mm.

[0016] In the above technical solution, further: in step S5, the synchronous displacement speed of the upper and lower rollers in the vertical direction is 0-2 mm / s; the slope of the tapering waist of the center rail is 0-1:125; and the rotation speed of the upper and lower rollers is 8 rpm.

[0017] In the above technical solution, further: in step S6, the synchronous displacement speed of the upper and lower rollers in the vertical direction is 5-10 mm / s; the rotation speed of the upper and lower rollers is 8 rpm; the slope of the gradually thickening tail of the center rail is 1:23-35.

[0018] In the above technical solution, further: the continuous through-type induction heating furnace is composed of a plurality of induction heating furnaces, and adjacent induction heating furnaces are connected in series transversely and concentrically via transmission rollers to form a continuous through-type induction heating furnace group.

[0019] The advantages of the present invention compared with the prior art are:

[0020] 1. The present invention adopts the flat rollers of the hydraulic roll forging machine for roll forging production. The upper and lower rollers have the functions of synchronous pressing and rotation, which can achieve uniform and gradual forming of the inclined surfaces on both sides of the heart rail with high dimensional accuracy.

[0021] 2. Heart rails of different rail types and numbers can be roll forged using flat rollers of the same specifications without the need to replace the mold. The equipment and tooling have strong process applicability and low production costs.

[0022] 3. Rectangular cross-section billets are used for roll forging production. There is no need to make special roll forging dies to make the billets. Flat rolls are used for direct forging, which reduces the number of process steps. Frog rails of different rail types and numbers can all be formed in one fire.

[0023] 4. The forging manipulator clamps the blank and separates it from the upper and lower rollers under the combined action of friction and the drawing force provided by the manipulator. Since the blank always maintains a certain tension during the roll forging process, the final forging will not have the bending and twisting problems that are inevitable in conventional free forging production. There is no need for an additional straightening process, and the forging has good straightness, which is close to the forming effect of closed die forging. There is no need for straightening, the process is simple, and the production is efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of a rectangular cross-section blank before processing the No. 60-12 center rail according to the present invention;

[0025] Figure 2 The front view of the No. 60-12 center rail processed and formed by the present invention;

[0026] Figure 3 This is a schematic diagram of roll forging in step S1 of the present invention;

[0027] Figure 4 This is a schematic diagram of the first roll forging process in step S2 of the present invention;

[0028] Figure 5 This is a schematic diagram of the second roll forging process in step S2 of the present invention;

[0029] Figure 6 This is a schematic diagram of the third roll forging process in step S2 of the present invention;

[0030] Figure 7 This is a schematic diagram of the bite-in state of the roll forging of the suddenly tapered waist of the center rail in step S4 of the present invention;

[0031] Figure 8 This is a schematic diagram of the tapering waist state of the core rail formed in step S5 of the present invention;

[0032] Figure 9 This is a schematic diagram of the biting state of the gradually thickened tail of the formed heart rail in step S6 of the present invention;

[0033] Figure 10 This is a schematic diagram of roll forging of the gradually thickened tail portion of the center rail in step S6 of the present invention;

[0034] Figure 11 It is a process flow chart of the present invention;

[0035] Figure 12 This is a schematic diagram of the structure of a continuous pass-through induction heating furnace;

[0036] In the figure: 1-center rail, center rail gradually thickening tip 101, center rail suddenly tapering waist 102, center rail gradually tapering waist 103, center rail gradually thickening tail 10, 2-upper roller, 3-lower roller, 4-induction heating furnace, 5-transmission roller. DETAILED DESCRIPTION

[0037] The following is a combination of the embodiments of the present invention Figure 1-12 The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0038] A frog rail roll forging method comprises the following steps: heating a rectangular cross-section blank in a continuous through-type induction heating furnace before forging; clamping one end of the blank by a forging manipulator, and roll-forging the other end of the blank on a hydraulic roll forging machine to form a rail tip; turning the blank, clamping the rail tip forming end of the blank by the forging manipulator, and roll-forging the other end of the blank on the hydraulic roll forging machine in sequence to form a rail waist and a rail tail.

[0039] In the above embodiment, further: the upper and lower rollers of the hydraulic roll forging machine are both flat rollers; and the diameters of the upper and lower rollers are 300-500 mm.

[0040] It should be noted that the "hydraulic roll forging machine" used in the above-mentioned roll forging production process is a prior art, as disclosed in the Chinese patent entitled "A Hydraulic Roll Forging Machine" with publication number CN212121537U. The hydraulic roll forging machine involved in this patent has "upper and lower rollers adopting a flat roller structure, the bite of the workpiece adopts the middle bite, and the height dimensions of the workpiece with different cross sections are achieved by the synchronous downward pressure of the upper roller during the rotation of the upper and lower rollers. The upper roller of the hydraulic roll forging machine is fixedly mounted on the lower part of the movable crossbeam, and the lower roller is fixedly mounted on the upper part of the lower crossbeam. It is driven by hydraulic pressure and the upper roller is driven by the piston cylinder to adjust the upper and lower positions. The hydraulic motor drives the upper and lower rollers respectively to rotate in opposite directions. The upper and lower rollers are both flat structures, which can realize the continuous extension and forming of long shaft workpieces. The roll forging process is controlled by program. By adjusting the roller speed and the displacement of the upper roller separately or simultaneously, the height dimensions of different cross sections of long strip forgings can be controlled." It can be seen that the hydraulic roll forging machine has upper and lower flat rolls that are each powered by their own power, and can realize reciprocating roll forging.

[0041] The "forging manipulator" used in the aforementioned roll forging production process is prior art, as described in Chinese Patent Publication No. CN205464137U, entitled "A Forging Manipulator." It clamps the rail and moves along its length. During operation, when the front end of the rail is engaged by the upper and lower rollers of the hydraulic roll forging machine, the clamps of the forging manipulator grip the rail and move backward, maintaining a certain drawing tension on the rail forging. The forging tension of the forging manipulator and the friction between the upper and lower rollers of the hydraulic roll forging machine allow the rail to disengage and be rolled into shape.

[0042] (like Figure 12 (As shown in the above-mentioned roll forging production process, the continuous pass-through induction heating furnace used requires multiple induction heating furnaces 4. To achieve the continuous pass-through induction heating function: multiple induction heating furnaces 4 are used, and the multiple induction heating furnaces 4 are arranged in parallel and series. In particular, adjacent induction heating furnaces 4 are concentrically connected in series via transmission rollers 5 to form a continuous pass-through induction heating furnace group. This continuous pass-through induction heating furnace group is used to achieve the continuous pre-forging heating and transmission function of long axial workpieces, and is used to achieve efficient, continuous, and automated production of the forging heating process.

[0043] Among them, the continuous through-type induction heating furnace group and the hydraulic roll forging machine only need to select and design the appropriate furnace chamber and upper and lower rolls of appropriate sizes according to the different heart rail models. The remaining structures of all the above equipment not mentioned are existing technologies and do not need to be changed.

[0044] It can be seen that the present invention uses the flat rollers of the hydraulic roll forging machine for roll forging production. The upper and lower rollers have the functions of synchronous pressing and rotation, which can achieve uniform gradual forming of the inclined surfaces on both sides of the heart rail with high dimensional accuracy.

[0045] Furthermore, heart rails of different rail types and numbers can all be roll forged using flat rollers of the same specifications without having to change the mold. The equipment and tooling have strong process applicability and low production costs.

[0046] Secondly, rectangular cross-section billets are used for roll forging production. There is no need to make special roll forging dies to make the billets. Flat rolls are used for direct forging, which reduces the number of process steps. Different rail types and numbers of switch heart rails can be formed in one fire.

[0047] Finally, the forging manipulator clamps the blank and separates it from the upper and lower rolls under the combined action of the friction force provided by the hydraulic roll forging machine and the drawing force provided by the forging manipulator. Since the blank always maintains a certain tension during the roll forging process, the final forging will not have the bending and twisting problems that are inevitable in conventional free forging production. There is no need for an additional straightening process, the forging has good straightness, and the forming effect is close to that of closed die forging. There is no need for straightening, the process is simple, and production is efficient.

[0048] The present invention comprises the steps of:

[0049] (like Figure 3 Step S1, rough rolling of the mandrel with a gradually thickened tip: A rectangular cross-section billet, heated before forging in a continuous through-type induction heating furnace, is transferred from left to right between the upper and lower rolls of a hydraulic roll forging machine. The upper and lower rolls of the hydraulic roll forging machine rotate synchronously counterclockwise and gradually separate to form the mandrel with a gradually thickened tip 101. This means that the minimum thickness of the roll forging area B1 is reduced from the initial thickness of the billet to H1, and the total length of the billet is extended to L1.

[0050] Step S2, forming the gradually thickened tip of the center rail: repeating step S1 multiple times, and performing multiple roll forging passes to form the gradually thickened tip 101 of the center rail.

[0051] (like Figures 4 to 6 (As shown) Preferably: Step S2, forming the gradually thickened tip of the center rail: Repeat step S1 three times, and roll forge the gradually thickened tip of the center rail 101 in three passes until the cross-sectional dimensions of the roll forging B4 area meet the forming requirements of the gradually thickened tip of the center rail 101 in the drawing, i.e., the gradually thickened tip of the center rail 101 is roll-formed.

[0052] In the above embodiment, further: in step S1 and step S2, the synchronous pressing distance of the upper and lower rollers each time is 3 to 5 mm; the pressing speed of the upper and lower rollers is 0 to 10 mm / s; the rotation speed of the upper and lower rollers is 8 revolutions / minute; and the slope of the gradually thickened tip of the center rail is 1:57 to 96.

[0053] Example 1:

[0054] Taking the processing of 60-12 center rail as an example, in step S1 and step S2, the synchronous pressing distance of the upper and lower rollers each time is 5mm; the pressing speed of the upper and lower rollers is 3.2mm / s; the slope of the center rail gradually thickened tip 101 is 1:57; in the matching steps S1 and S2, the rotation speed of the upper and lower rollers is 8 rpm. The minimum thickness of the left side of the formed center rail gradually thickened tip 101 is 65mm, and the maximum thickness on the right side is 114mm (combined with Figure 2 ).

[0055] Example 2:

[0056] Taking the processing of a 50-18 center rail as an example, in steps S1 and S2, the synchronous pressing distance of the upper and lower rollers is 5 mm per roll; the pressing speed of the upper and lower rollers is 1.7 mm / s; the slope of the center rail tapered tip 101 is 1:96; and in steps S1 and S2, the rotation speed of the upper and lower rollers is 8 rpm. The resulting center rail tapered tip 101 has a minimum thickness of 71 mm on the left side and a maximum thickness of 114 mm on the right side.

[0057] Example 3:

[0058] Taking the processing of a 75-12 center rail as an example, in steps S1 and S2, the synchronous pressing distance of the upper and lower rollers is 5 mm per roll; the pressing speed of the upper and lower rollers is 4 mm / s; the slope of the center rail tapered tip 101 is 1:46; and in steps S1 and S2, the rotation speed of the upper and lower rollers is 8 rpm. The resulting center rail tapered tip 101 has a minimum thickness of 54 mm on the left side and a maximum thickness of 114 mm on the right side.

[0059] Step S3: turning the center rail.

[0060] (like Figure 7 Step S4, forming the tapered waist of the center rail: The turned center rail is conveyed from right to left between the upper and lower rollers of a hydraulic roll forging machine. When the center rail is 60 to 80 mm from the thickest position of the gradually thickening tip 101 of the center rail, the upper and lower rollers of the hydraulic roll forging machine rotate clockwise synchronously and press in the same distance to form the tapered waist 102 of the center rail. After the tapered waist 102 of the center rail is formed, the upper and lower rollers rotate clockwise synchronously away from the center rail. Under the action of friction, the center rail is separated from the upper and lower rollers. In the above embodiment, further: in step S4, the synchronous pressing distance of the upper and lower rollers is 5 to 8 mm.

[0061] Example 1:

[0062] Taking the processing of 60-12 center rail as an example, in step S4, the synchronous pressing distance of the upper and lower rollers is 5mm. The thickest dimension of the left side of the suddenly tapered waist 102 of the formed center rail is 114mm, and the minimum thickness on the right side is 75mm (combined with Figure 2).

[0063] Example 2:

[0064] Taking the processing of 50-18 center rail as an example, in step S4, the synchronous pressing distance of the upper and lower rollers is 5mm. The thickest dimension of the left side of the tapered waist 102 of the formed center rail is 114mm, and the minimum thickness on the right side is 80mm.

[0065] Example 3:

[0066] Taking the processing of 75-12 center rail as an example, in step S4, the synchronous pressing distance of the upper and lower rollers is 5mm. The thickest dimension of the left side of the tapered waist 102 of the formed center rail is 114mm, and the minimum thickness on the right side is 72mm.

[0067] (like Figure 8 Step S5: Forming the tapered waist of the core rail: The core rail is conveyed from left to right between the upper and lower rollers of the hydraulic roll forging machine, and the core rail is bitten into the thinnest end of the tapered waist 102 as the starting point. The upper and lower rollers rotate counterclockwise synchronously and press down the same distance to form the tapered waist 103 of the core rail (combined with Figure 9 After the tapering waist portion 103 of the heart rail is formed, the upper and lower rollers move away from the heart rail synchronously, and under the action of friction, the heart rail is separated from the upper and lower rollers.

[0068] Example 1:

[0069] Taking the processing of 60-12 center rail as an example, the total length of the formed center rail suddenly tapered waist 102 and the center rail gradually tapered waist 103 is 560mm, of which the left end of the center rail gradually tapered waist 103 is the thickest 75mm, and the right end of the center rail gradually tapered waist 103 is the thinnest 67mm (combined with Figure 2 ).

[0070] Example 2:

[0071] Taking the processing of 50-18 center rail as an example, the total length of the formed center rail suddenly tapered waist 102 and the center rail gradually tapered waist 103 is 990mm, among which the left end of the center rail gradually tapered waist 103 is the thickest at 80mm, and the right end of the center rail gradually tapered waist 103 is the thinnest at 80mm.

[0072] Example 3:

[0073] Taking the processing of 50-18 center rail as an example, the total length of the formed center rail suddenly tapered waist 102 and the center rail gradually tapered waist 103 is 990mm, among which the left end of the center rail gradually tapered waist 103 is the thickest at 80mm, and the right end of the center rail gradually tapered waist 103 is the thinnest at 80mm.

[0074] Step S6, forming the gradually thickened tail of the heart rail: the heart rail is conveyed from left to right, and the thinnest end of the gradually thin waist 103 of the heart rail is used as the starting point to bite into (such as Figure 9As shown), the upper and lower rollers rotate counterclockwise synchronously and gradually open and press. Under the action of friction, the blank moves from left to right and gradually separates from the upper and lower rollers to form the gradually thickened tail portion 104 of the heart rail (as shown). Figure 10 shown).

[0075] In the above embodiment, further: in step S5, the synchronous displacement speed of the upper and lower rollers in the vertical direction is 0-2 mm / s; the slope of the tapered waist portion 103 of the center rail is 0-1:125; and the rotation speed of the upper and lower rollers is 8 rpm.

[0076] In the above embodiment, further: in step S6, the synchronous displacement speed of the upper and lower rollers in the vertical direction is 5-10 mm / s; the rotation speed of the upper and lower rollers is 8 rpm; and the slope of the gradually thickened tail portion 104 of the center rail is 1:23-35.

[0077] Example 1:

[0078] Taking the processing of 60-12 center rail as an example, in step S5, the synchronous displacement speed of the upper and lower rollers in the vertical direction is 1.7mm / s; the slope of the center rail tapering waist 103 is 1:125; the rotation speed of the upper and lower rollers is 8 rev / min; in step S6, the synchronous displacement speed of the upper and lower rollers in the vertical direction is 8.7mm / s; the slope of the center rail tapering tail 104 is 1:23; the rotation speed of the upper and lower rollers is 8 rev / min. The thickness of the thinnest end of the formed center rail tapering tail 104 is 67mm, and the thickest size of the right end of the formed center rail tapering tail 104 is 103mm (combined with Figure 2 ).

[0079] Example 2:

[0080] Taking the processing of a 50-18 center rail as an example, in step S5, the vertical synchronous displacement speed of the upper and lower rollers is 0 mm / s, the slope of the center rail's tapered waist 103 is 0, and the rotation speed of the upper and lower rollers is 8 rpm. In step S6, the vertical synchronous displacement speed of the upper and lower rollers is 5.9 mm / s, the slope of the center rail's tapered tail 104 is 1:35, and the rotation speed of the upper and lower rollers is 8 rpm. The thickness of the formed center rail's tapered tail 104 at its thinnest end on the left is 74 mm, and the thickness of the formed center rail's tapered tail 104 at its thickest end on the right is 98 mm.

[0081] Example 3:

[0082] Taking the processing of a 75-12 center rail as an example, in step S5, the vertical synchronous displacement speed of the upper and lower rollers is 0 mm / s, the slope of the center rail's tapered waist 103 is 0, and the rotation speed of the upper and lower rollers is 8 rpm. In step S6, the vertical synchronous displacement speed of the upper and lower rollers is 8.7 mm / s, the slope of the center rail's tapered tail 104 is 1:24, and the rotation speed of the upper and lower rollers is 8 rpm. The thickness of the formed center rail's tapered tail 104 at its thinnest end on the left is 72 mm, and the thickness of the formed center rail's tapered tail 104 at its thickest end on the right is 99 mm.

[0083] The working principle of this invention is as follows: A continuous through-type induction heating furnace with its accompanying automatic loading, conveying, and discharging mechanisms facilitates efficient, continuous, and automated production during the forging heating process; forgings require only a single heating cycle. Pre-forging heating of rectangular cross-section billets reduces the pressing force required for roll forging, minimizing excess material processing, lowering material costs, and improving production efficiency. A hydraulic roll forging machine, utilizing its independently powered upper and lower flat rollers for reciprocating roll forging, enables roll forging of frog rails up to 4 meters in length, achieving low cost and high efficiency, suitable for high-volume, efficient production.

[0084] From the above description, it can be seen that the present invention uses a rectangular cross-section billet, which is heated before forging in a continuous pass-through induction heating furnace; a forging manipulator clamps one end of the billet and roll-forges the other end of the billet on a hydraulic roll forging machine to form the tip of the heart rail; then the billet is turned around, the forging manipulator clamps the formed end of the heart rail tip, and roll-forges the other end of the billet on the hydraulic roll forging machine to form the waist and tail of the heart rail, thereby solving the technical problem that the current frog heart rail cannot be produced in large quantities and at low cost.

[0085] In summary, the present invention utilizes a continuous through-type electric induction heating furnace and its associated automatic loading, conveying, and discharging mechanisms to achieve efficient, continuous, and automated production during the forging heating process. The use of rectangular cross-section rolled or forged blanks as raw materials reduces the pressing force required for roll forging, improving production efficiency. A dedicated hydraulic roll forging machine, equipped with self-powered flat rollers on both the upper and lower sides, and a reciprocating roll forging technique, enables efficient, low-cost, and high-quality roll forging of frog rails up to 4 meters in length.

[0086] Furthermore, the upper and lower rollers feature synchronous pressing and rotation, achieving uniform, gradual shaping of the inclined surfaces on both sides of the heart rail with high dimensional accuracy. Heart rails of varying rail types and numbers can be roll-forged using the same flat rollers, eliminating the need for die replacement. This makes the equipment and tooling highly adaptable and reduces production costs. Roll forging uses rectangular billets, eliminating the need for specialized roll forging dies. Direct roll forging with flat rollers reduces the number of process steps. Frog heart rails of varying rail types and numbers can be formed in a single pass. The forging manipulator grips the billet, which is released from the upper and lower rollers through a combination of friction and the pull-out force provided by the manipulator. Because the billet maintains a constant tension during the roll forging process, the resulting forging avoids the bending and twisting that inevitably occur with conventional open die forging. No additional straightening steps are required, resulting in excellent straightness, approaching that achieved by closed die forging. The process is simple, efficient, and practical, making it highly effective, stable, and reliable, making it suitable for widespread adoption.

[0087] Each embodiment in this specification is described in a related manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0088] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. A frog rail roll forging method, characterized in that: A rectangular cross-section billet is heated before forging using a continuous through-type induction heating furnace; one end of the billet is clamped by a forging manipulator, and the other end is roll-forged on a hydraulic roll forging machine to form the tip of the mandrel; The billet is turned over, the forging manipulator clamps the forming end of the billet's mandrel tip, and the other end of the billet is roll-forged on the hydraulic roll forging machine to form the mandrel waist and the mandrel tail; S1. Initial rolling of the mandrel rail to form a gradually thickened tip: a rectangular cross-section billet heated before forging in a continuous through-type induction heating furnace is conveyed from left to right between the upper and lower rollers of a hydraulic roll forging machine. The upper and lower rollers of the hydraulic roll forging machine rotate counterclockwise synchronously and gradually open and press. Under the action of friction, the billet moves from left to right and gradually separates from the upper and lower rollers, forming a gradually thickened tip of the mandrel rail by initial roll forging (101); S2, forming the gradually thickened tip of the center rail: repeating step S1 multiple times, and performing multiple roll forging to form the gradually thickened tip of the center rail (101); S3, center track U-turn; S4, forming the tapered waist of the heart rail: the turned heart rail is conveyed from right to left between the upper and lower rollers of the hydraulic roll forging machine, and when the distance from the thickest position of the gradually thickened tip (101) of the heart rail is 60 to 80 mm; the upper and lower rollers of the hydraulic roll forging machine are synchronously rotated clockwise and pressed in the same distance to form the tapered waist (102) of the heart rail; after the tapered waist (102) of the heart rail is formed, the upper and lower rollers are synchronously rotated clockwise to move away from the heart rail, and the heart rail is separated from the upper and lower rollers under the action of friction; S5, forming the tapered waist of the heart rail: the heart rail is conveyed from left to right between the upper and lower rollers of the hydraulic roll forging machine, and is bitten into the heart rail with the thinnest end of the tapered waist (102) as the starting point, and the upper and lower rollers rotate counterclockwise synchronously and press down the same distance synchronously to form the tapered waist (103) of the heart rail; after the tapered waist (103) of the heart rail is formed, the upper and lower rollers are synchronously away from the heart rail, and the heart rail is separated from the upper and lower rollers under the action of friction; S6, forming the gradually thickened tail of the heart rail: the heart rail is conveyed from left to right, and the thinnest end of the gradually thin waist (103) of the heart rail is used as the starting point for biting, and the upper and lower rollers rotate counterclockwise synchronously and gradually open and press synchronously. Under the action of friction, the blank moves from left to right and gradually separates from the upper and lower rollers, and the gradually thickened tail (104) of the heart rail is formed by roller forging; The upper and lower rollers are both flat rollers.

2. The frog rail roll forging method according to claim 1, characterized in that: The diameters of the upper and lower rollers are 300 to 500 mm.

3. The frog rail roll forging method according to claim 1, wherein: In step S1 and step S2, the synchronous pressing distance of the upper and lower rollers is 3 to 5 mm; the pressing speed of the upper and lower rollers is 0 to 10 mm / s; the rotation speed of the upper and lower rollers is 8 revolutions / minute; and the slope of the gradually thickened tip (101) of the center rail is 1:57 to 96.

4. The frog rail roll forging method according to claim 1, wherein: In step S4, the synchronous pressing distance of the upper and lower rollers is 5 to 8 mm.

5. The frog rail roll forging method according to claim 1, wherein: In step S5, the synchronous displacement speed of the upper and lower rollers in the vertical direction is 0 to 2 mm / s; the slope of the tapering waist (103) of the center rail is 0 to 1:125; and the rotation speed of the upper and lower rollers is 8 revolutions per minute.

6. The frog rail roll forging method according to claim 1, characterized in that: In step S6, the synchronous displacement speed of the upper and lower rollers in the vertical direction is 5 to 10 mm / s; the rotation speed of the upper and lower rollers is 8 revolutions / minute; and the slope of the gradually thickening tail portion (104) of the center rail is 1:23 to 35.

7. The frog rail roll forging method according to claim 1, wherein: The continuous through-type induction heating furnace is composed of a plurality of induction heating furnaces (4), and adjacent induction heating furnaces (4) are connected in series in a transverse and concentric manner via transmission rollers (5) to form a continuous through-type induction heating furnace group.

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