A method of processing a welded rail

Abstract

The application discloses a processing method of a welded center rail, which comprises the following steps: placing a workpiece on a processing tool; the workpiece comprises a front-end alloy head and a rear-end connecting rail; the processing tool comprises an electric permanent magnetic chuck, a bidirectional center-finding vice, a lateral top-adjusting screw rod, a connecting rail auxiliary support and a pressing mechanism; clamping and aligning the workpiece, which comprises clamping and positioning the front-end alloy head by using the bidirectional center-finding vice; after the aligning is completed, the two connecting rails are pressed by using the pressing mechanism in the connecting rail auxiliary support and the pressing mechanism. The method is used for the overall linear processing of the center rail blank workpiece after the flash welding of the forged alloy head and the standard hard head rail. Through a series of software and hardware means, the high-precision working linear of the welded center rail is ensured, the processed center rail of the type is used as the core component of the CN turnout, the high-speed and high-comfort operation of the train is ensured, and the economic and social benefits are obvious.

Description

A method for processing welded mandrels Technical Field

[0001] This invention relates to the field of rail processing technology, and in particular to a method for processing welded core rails. Background Technology

[0002] With the development of the national economy, railway transportation volume has been continuously increasing. In order to improve the speed and capacity of railway lines, multiple speed increases have been implemented, which has placed high demands on the construction of rail lines, especially the renovation of existing lines. Currently, alloy steel composite frogs are widely used for high-speed railway turnouts. Their frogs are forged from high-wear-resistant, high-strength and high-toughness alloy steel and spliced ​​with the rear fork rail, greatly improving the service life of the frogs.

[0003] Traditional high-speed turnout movable frogs are typically made by machining standard rails into long and short frogs, which are then bolted together. The disadvantages are that the assembled structure has poor overall integrity, causing vibrations when trains pass, affecting ride comfort. Furthermore, the assembled structure is not conducive to the transfer of temperature stress, and the connecting bolts are prone to fatigue, affecting the service life of the frog.

[0004] As a new generation of alloy steel core rail, the front part is forged from high-carbon alloy steel, while the rear part uses a 60kg standard hardened rail as the heel connection rail, which is connected to the front alloy head using flash welding. Welding eliminates the defects caused by bolted connections and improves the overall integrity of the frog. Compared with other welding methods, flash welding has advantages such as shorter heating time, no need for filler metal, simpler metallurgical process, smaller heat-affected zone, and easier acquisition of high-quality weld joints. Therefore, it can be used for welding rails or turnouts in factories, and can also be performed on-site using rail welding trains. Consequently, it is widely used in the railway equipment manufacturing field.

[0005] Before flash welding, the general shape elements of the mandrel, such as the alloy head end face, mounting holes, grooves, and bottom surface, as well as the general shape elements of the connecting rail, such as the rail web hole, rail bottom, and rail head traveling surface, are all machined in a single-piece state. However, for the traveling crane, the crucial double working edges, which have a margin at the top of the alloy head, need to be machined after welding.

[0006] However, since flash welding is a special process that is difficult to control in terms of shape and size, a series of methods are required for processing control in order to achieve the high precision requirements of the working edge profile on both sides of the entire welding core rail (including the connecting rail). Summary of the Invention

[0007] This invention provides a method for processing welded mandrels.

[0008] This invention provides the following solution:

[0009] A method for processing a welded mandrel, comprising:

[0010] The workpiece is placed on the machining fixture; the workpiece includes a front alloy head and a rear connecting rail; the machining fixture includes an electro-permanent magnetic chuck, a bidirectional centering vise, a lateral adjusting screw, a connecting rail auxiliary support, and a clamping mechanism; the electro-permanent magnetic chuck is used to attract the bottom surface of the workpiece; the bidirectional centering vise is used to position and clamp the workpiece in the width direction; the lateral adjusting screw is used to laterally align the workpiece at the welding position; the connecting rail auxiliary support and clamping mechanism are used to support and clamp the connecting rail as it approaches the machining area;

[0011] The workpiece is clamped and aligned. The clamping and alignment includes using the bidirectional centering vise to clamp and position the front alloy head, and activating the electro-permanent magnet chuck to attract the front alloy head and the heel end connecting rail near the welding position. The distance between the heel end connecting rail near the welding position is adjusted to the target size by the rail distance adjustment and fixing device, and the center of the rail distance width is aligned with the center of the front alloy head.

[0012] After alignment, the two connecting rails are pressed together using the pressing mechanism in the connecting rail auxiliary support and pressing mechanism.

[0013] Use a form milling cutter to complete local pre-milling and working edge milling;

[0014] Use a face milling cutter to remove the steps left in the middle area when the forming milling cutter is used to machine both sides. The cutting height during milling should be close to the center of the top surface of the working edge on both sides.

[0015] Preferably: the step of adjusting the track spacing to the target size using the track spacing adjustment and fixing device, and aligning the center of the track spacing width with the center of the front alloy head, includes:

[0016] Take the relatively fixed and high-precision edge of the workbench or the edge of the tooling after cutting and alignment as the reference zero line. Use alignment measuring tools to measure the distance of the outer point 16mm below the rail at each alignment position relative to the reference zero line, and adjust the lateral tightening screws on both sides to correct the position.

[0017] Preferably, the track spacing adjustment and fixing device includes fixing bolts, washers, spacers, and forward and reverse adjustment bolts; the alignment measuring tool includes an L-shaped magnetic base, a magnetic switch, a height-direction main scale, a horizontal-direction vernier scale, a horizontal-direction main scale, fastening screws, and a height-direction vernier scale.

[0018] Preferably, the local pre-milling includes taking an allowance of about 2mm on each side in the width direction to process the working edges of the front alloy head of the welding part in several times, and checking the step height of the milled surface on the side relative to the connecting rail. If it is relatively uniform, then proceed with subsequent milling. If it is not uniform, then the zero point value of the Y axis needs to be slightly corrected according to the measurement results until the milled surface on both sides of the front alloy head is consistent with the step height of the corresponding heel end connecting rail.

[0019] Preferably, the working edge milling includes using a form milling cutter to mill the working edges on both sides of the front alloy head in 3-4 passes according to the Y-axis zero point coordinates adjusted by local pre-milling. The tool running path includes entering obliquely from one side of the workpiece, after the flash welding point, to the actual tip according to the drawing line, and then the tool moves to the other side for symmetrical back-turn machining, and exits obliquely from the corresponding position of the heel end connecting rail.

[0020] Preferably, during the feed, after the milling depth covers the local pre-milling position, the step height of the milled surface on the side and top surface relative to the heel end connecting rail is measured for each feed, and the feed values ​​in the Y and Z directions are adjusted accordingly.

[0021] When adjusting the Z value, the feed dimensions on both sides are slightly differentiated according to the actual height of the heel end connecting rail, until the working edge of the front alloy head is smoothly connected to the heel end connecting rail. The milling tool runs close to the surface of the heel end connecting rail and makes a slight cut. At the weld point, the cutting surface extends inward from the top surface beyond the center of the top of the heel end connecting rail, and is 16mm lower than the side of the heel end connecting rail.

[0022] Preferably, the machining fixture is aligned before use. The alignment includes cutting alignment using a face milling cutter under the same Z-coordinate on the machine tool and alignment using a bidirectional centering vise.

[0023] Preferably, both the electro-permanent magnet chuck and the bidirectional centering vise comprise multiple units and are distributed along the length of the machining fixture.

[0024] Preferably, the workpiece clamping surface of the jaws of the bidirectional centering vise is a plane or arc surface for forming point contact.

[0025] Preferably, the machining fixture further includes a tail steel structure support.

[0026] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0027] This invention provides a method for processing a welding mandrel. In one implementation, the method includes placing a workpiece on a processing fixture. The workpiece includes a front alloy head and a rear connecting rail. The processing fixture includes an electro-permanent magnetic chuck, a bidirectional centering vise, a lateral adjusting screw, a connecting rail auxiliary support, and a clamping mechanism. The electro-permanent magnetic chuck is used to attract the bottom surface of the workpiece. The bidirectional centering vise is used to position and clamp the workpiece in the width direction. The lateral adjusting screw is used to laterally align the workpiece at the welding position. The connecting rail auxiliary support and clamping mechanism are used to support and clamp the connecting rail near the processing area. The workpiece is clamped and aligned. The clamping and alignment process includes clamping and positioning the front alloy head using the bidirectional centering vise, and activating the electro-permanent magnet chuck to attract the front alloy head and the heel connecting rail near the welding position. The distance between the heel connecting rails near the welding position is adjusted to the target size using a rail spacing adjustment and fixing device, and the center of the rail spacing width is aligned with the center of the front alloy head. After alignment, the two connecting rails are pressed together using the clamping mechanism in the connecting rail auxiliary support and clamping mechanism. A forming milling cutter is used to perform local pre-milling and working edge milling. A face milling cutter is used to remove the residual steps in the middle area from the working edge milling cutter on both sides, with the cutting height during milling based on the center of the top surface of the working edges on both sides. This method is used for the overall linear machining of the core rail blank workpiece after flash welding of the forged alloy head and standard hardened head rail. Through a series of software and hardware measures, a high-precision working line shape of the welded core rail is ensured. As a core component of CN turnouts, this type of core rail ensures high-speed and high-comfort train operation, resulting in significant economic and social benefits.

[0028] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 is a schematic diagram of the processing fixture provided in an embodiment of the present invention;

[0031] Figure 2 is a schematic diagram of the first partial structure of the machining fixture provided in an embodiment of the present invention;

[0032] Figure 3 is a schematic diagram of the second partial structure of the machining tooling provided in an embodiment of the present invention;

[0033] Figure 4 is a schematic diagram of the third partial structure of the machining tooling provided in an embodiment of the present invention;

[0034] Figure 5 is a schematic diagram of the track spacing adjustment and fixing device provided in an embodiment of the present invention;

[0035] Figure 6 is a schematic diagram of the alignment gauge provided in an embodiment of the present invention;

[0036] Figure 7 is a structural schematic diagram of the alignment gauge provided in the embodiment of the present invention in use.

[0037] Figure 8 is a data identification diagram for aligning the 42# core track as an example provided in an embodiment of the present invention;

[0038] Figure 9 is a schematic diagram of the anti-jumping platform for milling the tip from the side of the workpiece provided in an embodiment of the present invention;

[0039] Figure 10 is a schematic diagram of partial pre-milling provided in an embodiment of the present invention;

[0040] Figure 11 is a schematic diagram of working edge milling provided in an embodiment of the present invention;

[0041] Figure 12 is a schematic diagram of the process of milling the middle step of the top surface according to an embodiment of the present invention;

[0042] Figure 13 is a front view of the CN42# movable center rail provided in an embodiment of the present invention;

[0043] Figure 14 is a top view of the CN42# movable guide rail provided in an embodiment of the present invention;

[0044] Figure 15 is a cross-sectional view of the AA plane provided in an embodiment of the present invention;

[0045] Figure 16 is a BB-side cross-sectional view provided in an embodiment of the present invention;

[0046] Figure 17 is a cross-sectional view of the CC plane provided in an embodiment of the present invention.

[0047] In the diagram: 1. Machining fixture; 11. Electro-permanent magnet chuck; 12. Two-way centering vise; 13. Lateral top adjustment screw; 14. Connecting rail auxiliary support and clamping mechanism; 15. Tail steel structure support; 2. Rail spacing adjustment and fixing device; 21. Fixing bolt; 22. Washer; 23. Spacer; 24. Positive and negative snap adjustment bolt; 3. Alignment measuring tool; 31. L-shaped magnetic base; 32. Magnetic switch; 33. Height direction main scale; 34. Horizontal direction vernier scale; 35. Horizontal direction main scale; 36. Fastening screw; 37. Height direction vernier scale; 4. Front alloy head; 5. Heel connecting rail. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0049] Example

[0050] This invention provides a method for processing welded mandrels, which may include:

[0051] The workpiece is placed on the machining fixture 1. As shown in Figures 1, 2, 3, and 4, the workpiece includes a front alloy head 4 and a rear connecting rail 5. The machining fixture 1 includes an electro-permanent magnetic chuck 11, a bidirectional centering vise 12, a lateral adjusting screw 13, and a connecting rail auxiliary support and clamping mechanism 14. The electro-permanent magnetic chuck 11 is used to adsorb the bottom surface of the workpiece. The bidirectional centering vise 12 is used to position and clamp the workpiece in the width direction. The lateral adjusting screw 13 is used to laterally align the workpiece at the welding position. The connecting rail auxiliary support and clamping mechanism 14 is used to support and clamp the connecting rail near the machining area. Specifically, multiple electro-permanent magnetic chucks 11 and bidirectional centering vises 12 are included and distributed along the length of the machining fixture 1. The workpiece clamping surface of the jaws of the bidirectional centering vise 12 is a small-sized flat or curved surface. To support extra-long workpieces, this embodiment of the application may also provide that the machining fixture 1 includes a tail steel structure support 15.

[0052] The workpiece is clamped and aligned. The clamping and alignment includes using the bidirectional centering vise 12 to clamp and position the front alloy head 4, and activating the electro-permanent magnet chuck to attract the front alloy head 4 and the heel end connecting rail 5 near the welding position. The spacing of the heel end connecting rail 5 near the welding position is adjusted to the target size by the rail spacing adjustment and fixing device 2, and the center of the rail spacing width is aligned with the center of the front alloy head 4.

[0053] After alignment, the two connecting rails are pressed together using the pressing mechanism in the connecting rail auxiliary support and pressing mechanism 14.

[0054] Partial pre-milling and working edge milling are performed using a form milling cutter. Specifically, the partial pre-milling involves machining the working edges of the front alloy head at the welding location on both sides in several passes with an allowance of approximately 2mm on each side in the width direction. The step height of the milled surface relative to the connecting rail is checked. If it is relatively uniform, subsequent milling is performed. If it is not uniform, the Y-axis zero point value needs to be slightly corrected based on the measurement results until the milled surfaces on both sides of the front alloy head are consistent with the step height of the corresponding heel end connecting rail. The working edge milling involves using a form milling cutter to mill the working edges on both sides of the front alloy head in 3-4 passes according to the Y-axis zero point coordinates adjusted by the partial pre-milling. The tool path includes entering obliquely from one side of the workpiece, after the flash welding point, to the actual tip according to the drawing line, then moving the tool to the other side for symmetrical back-turn machining, and exiting obliquely from the corresponding position of the heel end connecting rail.

[0055] After the milling depth covers the local pre-milling position, the step height of the milled surface relative to the heel end connecting rail is measured on the side and top surface with each cut, and the feed values ​​in the Y and Z directions are adjusted accordingly.

[0056] When adjusting the Z value, the feed dimensions on both sides are slightly differentiated according to the actual height of the heel end connecting rail, until the working edge of the front alloy head is smoothly connected to the heel end connecting rail. The milling tool runs close to the surface of the heel end connecting rail and makes a slight cut. At the weld point, the cutting surface extends inward from the top surface beyond the center of the top of the heel end connecting rail, and is 16mm lower than the side of the heel end connecting rail.

[0057] Use a face milling cutter to remove the steps left in the middle area when the forming milling cutter is used to machine both sides. The cutting height during milling should be close to the center of the top surface of the working edge on both sides.

[0058] The processing method for the welded mandrel provided in this application embodiment, based on the relative positional relationship between the heel end connecting rail and the front end alloy head after the mandrel flash welding, uses a series of hardware and software measures such as processing tooling 1 and rail spacing adjustment and fixing device 2 to ultimately achieve the mandrel meeting the strict manufacturing technical requirements.

[0059] Furthermore, adjusting the track spacing of the heel connection near the welding position to the target size using the track spacing adjustment and fixing device 2, and aligning the center of the track spacing width with the center of the front alloy head, includes:

[0060] Take the relatively fixed and high-precision edge of the workbench or the edge of the tooling after cutting and alignment as the reference zero line. Use the alignment measuring tool 3 to measure the distance of the outer point 16mm below the rail at each alignment position relative to the reference zero line. Adjust the tightening screws on both sides of the rail spacing adjustment and fixing device 2 to correct the position.

[0061] As shown in Figure 5, the track spacing adjustment and fixing device 2 includes a fixing bolt 21, a washer 22, a spacer 23, and a forward / reverse adjustment bolt 24; as shown in Figure 6, the alignment measuring tool 3 includes an L-shaped magnetic base 31, a magnetic switch 32, a height-direction main scale 33, a horizontal-direction vernier scale 34, a horizontal-direction main scale 35, a fastening screw 36, and a height-direction vernier scale 37. The specific structure and usage of the track spacing adjustment and fixing device 2 and the alignment measuring tool 3 will be described in detail later.

[0062] To further improve the alignment effect, this application embodiment can also provide tooling alignment of the machining tooling 1 before use. The tooling alignment includes cutting alignment using a face milling cutter under the same Z-coordinate of the machine tool and alignment using the bidirectional centering vise 12.

[0063] The methods and hardware devices used in the embodiments of this application will be described in detail below.

[0064] The method for machining the welded movable point rail of high-speed turnout includes machining fixture 1 and its alignment, rail spacing adjustment and fixing device 2 and alignment gauge 3, workpiece clamping and alignment process, main machining methods and tool selection.

[0065] The movable point of the CN series high-speed turnout: the front part is forged from high-carbon alloy steel, and the rear part uses a 60Kg standard hardened rail as the heel end connecting rail, which is connected to the front alloy head by flash welding. Its specific structure is shown in Figures 13, 14, 15, 16, and 17 (taking CN42# movable point as an example).

[0066] Before flash welding, the general shape elements of the mandrel, such as the alloy head end face, mounting holes, grooves, and bottom surface, as well as the general shape elements of the connecting rail, such as the rail web hole, rail bottom, and rail head travel surface, are all machined in a single-piece state. However, for the crane, the crucial double working edges, which have a allowance on the upper part of the alloy head, need to be machined after welding. To achieve the high-precision requirements for the double working edge profile of the entire welded mandrel (including the connecting rail), its machining must be controlled through a series of methods, starting with the selection of tooling, clamping and alignment, the main machining methods, and the selection of forming tools. These methods include:

[0067] Post-welding mandrel machining fixture 1 and its alignment:

[0068] The main structure of the post-weld mandrel machining fixture 1 includes a two-way centering vise 12, an electro-permanent magnet chuck 11, a lateral top-adjusting screw 13, a connecting rail auxiliary support and clamping mechanism 14, and a tail steel structure support 15 (including the clamping mechanism).

[0069] The CN turnout welding point rail is generally a long rod, with its various shape elements distributed along the length of the workpiece. Therefore, the main structure of the tooling is as follows:

[0070] a. Electro-permanent magnetic chucks 11 are spaced apart along the length direction, mainly used for adsorbing the bottom surface of workpieces. After being magnetized by a single power-on, they do not lose their magnetism when the power is turned off. The adsorption force should be 160 N / cm. 2 above.

[0071] b. Two-way centering vises 12 are distributed at intervals along the length direction to position and clamp the workpiece in the width direction. The jaws on both sides open and close synchronously. The repeatability of positioning accuracy is required to be above 0.1mm. The workpiece clamping surface of the jaws is a small plane or arc surface to make the clamping tend to point contact.

[0072] c. Lateral adjusting screws 13 are installed before and after the welding position for lateral alignment of the workpiece in this section.

[0073] d. The tail end is equipped with a connecting rail auxiliary support and a clamping mechanism 14, which improves the stability of the connecting rail when it approaches the processing area;

[0074] e. When the length of the connecting rail exceeds the worktable, the tooling needs to be equipped with a tail steel structure support 15 (including a clamping mechanism).

[0075] f. Positioning keys and fastening bolts must be installed between the main structure and between the main structure and the worktable at each level of the component to ensure connection strength and accuracy.

[0076] Alignment before using tooling:

[0077] a. Alignment of the electro-permanent magnet chuck and auxiliary support: Use a face milling cutter to perform cutting alignment under the same Z-coordinate on the machine tool, in two steps: rough milling and finish milling, to ensure the positioning accuracy of the fixture on the workpiece in the height direction.

[0078] b. Two-way centering vise 12 alignment: Clamp the lower part of all vise jaws with spacers of the same length to overcome the gap error of the vise itself. Then use an end mill to rough mill and finish mill the jaws along the X-axis of the machine tool to ensure the positioning accuracy of the fixture on the workpiece in the width direction. At the same time, record the coordinate values ​​when finishing milling the jaws on both sides, and take the center as the center coordinate of the fixture (that is, the center coordinate of the workpiece width).

[0079] As shown in Figures 6 and 7, the alignment measuring tool 3 includes: a magnetic base 31, a magnetic switch 32, a height-direction main scale 33, a horizontal-direction vernier scale 34, a horizontal-direction main scale 35, a fastening screw 36, and a height-direction vernier scale 37.

[0080] a. An L-shaped magnetic base 31, when in use, rotating the magnetic switch 32 can stably fix the measuring tool to the right-angled edge of the workbench or tooling. The two straight sides of the L-shape serve as the zero-point planes in the height and horizontal directions, respectively, and the reading values ​​in the height and horizontal directions correspond to the zero-point planes in their respective directions.

[0081] b. The reading structure is a vernier scale in both the height and horizontal directions, and the vernier scales in both directions are fixed as one piece, with a reading accuracy of 0.02mm.

[0082] c. The height main scale 33 is fixed to the magnetic base 31, the height direction vernier scale 37 can move and be fixed along the height main scale 33, and can also move along the horizontal main scale 35.

[0083] d. The horizontal main scale 35 can move and be fixed in the groove of the horizontal vernier scale 34 along the horizontal direction. Its front end measuring position is a gradually decreasing structure, which is equivalent to point contact with the workpiece being measured.

[0084] The track spacing adjustment device 2 includes a fixing bolt 21, a washer 22, a spacer 23, and a forward and reverse adjustment bolt 24.

[0085] In use, the main body of the device (including spacer 23, reversible adjustment bolt 24, and the distance between the two spacers 23 is appropriately reduced) is inserted forward from the wider position of the connecting rail. Then, the outer cylinders of the two spacers 23 are aligned with the corresponding rail web holes on both sides. The reversible adjustment bolt 24 (one side has a left-hand thread and the other side has a right-hand thread) is rotated to make the main outer contours of the two spacers 23 fit tightly against the inner rail web of the two rails for initial fixation. Then, the fastening bolts 21 and washers 22 on both sides are inserted into the rail web holes of the rails from the outside to fix them to the spacers 13. At this time, rotating the reversible adjustment bolt 24 can adjust and fix the distance between the two connecting rails.

[0086] Workpiece clamping and alignment:

[0087] The workpiece is hoisted to the corresponding position of the tooling, and the positioning alloy head is clamped by a two-way centering vise 12. The electro-permanent magnet chuck is then activated to attract the alloy head and the connecting rail near the welding position.

[0088] Alignment of the rail connection area near the welding point (generally four alignment points are used, spaced 300mm apart):

[0089] Since flash welding cannot guarantee that the relative positions of the two connecting rails on both sides are strictly consistent on each workpiece, in order to ensure the positional relationship between the alloy head and the connecting rail, the rail spacing of the two connecting rails near the welding point (i.e., the spacing 16mm below the outer side of the rail, which can be measured using a rail gauge commonly used in the turnout field) needs to be adjusted to the target size through the rail spacing adjustment and fixing device 2, and then its width center is aligned with the center of the alloy head (i.e., the center of the clamp).

[0090] However, once the rail spacing at each alignment position of the two connecting rails is fixed, its center is only an imaginary point without any physical support, making it difficult to measure. Therefore, when aligning the center rail, the edge of the workbench (or the edge of the tooling after alignment) with a relatively fixed position and high precision is taken as the reference zero line. A special alignment measuring tool 3 is used to measure the distance from the outermost point 16mm below the rail at each alignment position relative to the reference zero line (i.e., the distance from the center of the clamp to the reference line - half the 16mm gap between the two connecting rails). The tightening screws on both sides are then adjusted to correct the position. The alignment diagram is as follows:

[0091] As shown in Figure 8, the distance from the center of the clamp to the edge of the workbench is 400. It needs to be adjusted to 400 minus half the width of the two connecting rails, which corresponds to the reference points at the front end face distances of 10117, 10417, 10717, and 11017. The corrected distance values ​​for adjusting the tightening screws on both sides are 319.3, 316.8, 314.1, and 311.4, respectively.

[0092] Connecting rail clamping:

[0093] After alignment, the two connecting rails are pressed together using the clamping mechanism in the auxiliary support and clamping mechanism 14 and the tail steel structure support 15 to prevent the workpiece from moving during machine tool table operation and processing.

[0094] Main machining processes and tool selection:

[0095] Using a Φ200 circumferential milling cutter, as shown in Figure 9, the cutter is fed from the side of the workpiece to mill the anti-jump platform at the tip of the mandrel.

[0096] Pre-milling of welded areas:

[0097] As shown in Figure 10, in order to ensure the linear accuracy of the working edges of each section, special forming milling cutters are used for local pre-milling and working edge milling. That is, the cutting edge shape of the cutter is designed according to the workpiece profile, and various types of inserts are used to overlap. This can ensure the dimensional accuracy, shape consistency and high productivity of the machined workpiece.

[0098] The basic process of local pre-milling is as follows: Take an allowance of about 2mm on each side in the width direction and machine the working edges of the alloy head on both sides of the welding part in several times. Check the step height of the milled surface on the side relative to the connecting rail (the main measurement point is 16mm below the side of the connecting rail). If it is relatively uniform, then proceed with subsequent milling. If it is not uniform, the zero point value of the Y axis needs to be slightly corrected according to the measurement results until the step height of the milled surface on both sides of the alloy head is consistent with that of the corresponding connecting rail.

[0099] Workside milling:

[0100] As shown in Figure 11, a special forming milling cutter is used to mill the working edges on both sides of the alloy head in 3-4 passes according to the Y-axis zero point coordinates that have been adjusted by local pre-milling. The basic path of the tool is as follows: the tool enters obliquely from one side of the workpiece, after a certain length of the connecting rail position after the flash welding point, and moves to the actual tip according to the line shape of the drawing. Then the tool moves to the other side, performs symmetrical back-turn machining, and exits obliquely from the corresponding position of the connecting rail.

[0101] During the feed, after the milling depth covers the local pre-milling position, the step height of the milled surface relative to the connecting rail should be measured on the side (the main measurement point is 16mm below the side of the connecting rail) and the top surface (the main measurement point is the top center of the connecting rail) with respect to the connecting rail for each feed. Adjust the feed values ​​in the Y and Z directions (i.e., feed values ​​in the width and height directions) accordingly. When adjusting the Z value, the feed dimensions on both sides can be slightly differentiated according to the actual height of the connecting rail, until the working edge of the alloy head is smoothly connected to the connecting rail. At this time, the milling tool should run close to the surface of the connecting rail head and make a slight cut. At the weld point, the cutting surface should extend inward beyond the top center of the connecting rail on the top surface and be 16mm below the side of the connecting rail on the side.

[0102] A step remains in the middle of the top surface after milling:

[0103] As shown in Figure 12, since the alloy head and tail have a large width within a certain length, the working edge milling cutter cannot cut the entire workpiece when machining on both sides, and there will be a residual step in the middle area. Therefore, a face milling cutter is used to remove this local area. When milling, the cutting height should be close to the center of the top surface of the working edge on both sides.

[0104] The machining method for the welding mandrel provided in this application employs a bidirectional centering vise and cutting alignment, which improves clamping accuracy and speed compared to adjusting the workpiece center with set screws on both sides. Electromagnetic adsorption of the workpiece, compared to mechanical or hydraulic clamping, solves the problems of insufficient clamping points at the bottom of the workpiece and obstruction of the machining position when clamping at the top. The specialized measuring tools and methods used for workpiece alignment overcome the difficulty of finding the solid center using general measuring tools and machine tool coordinate alignment. The machining method of pre-milling the welding position and step-by-step measurement and tool entry precisely centers the workpiece, ensuring a smooth and precise connection between the working edges on both sides of the alloy head and the corresponding connecting rail. Compared to fixed coordinate tool entry, this solves the problem of workpieces being discarded due to poor workpiece accuracy caused by overcutting or undercutting of the connecting rail.

[0105] In summary, the welding point rail processing method provided in this application is for processing the overall profile of a point rail blank workpiece that is flash-welded between a forged alloy head and a standard hardened head rail. Through a series of software and hardware measures, the high-precision working profile of the welding point rail is ensured. As a core component of CN turnouts, this type of point rail ensures high-speed and high-comfort operation of trains, resulting in significant economic and social benefits.

[0106] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0107] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A method for processing a welded mandrel, characterized in that, include: The workpiece is placed on the machining fixture; the workpiece includes a front alloy head and a rear connecting rail; the machining fixture includes an electro-permanent magnetic chuck, a bidirectional centering vise, a lateral adjusting screw, a connecting rail auxiliary support, and a clamping mechanism; the electro-permanent magnetic chuck is used to adsorb the bottom surface of the workpiece; the bidirectional centering vise is used to position and clamp the workpiece in the width direction; the lateral adjusting screw is used to laterally align the workpiece at the welding position; the connecting rail auxiliary support and clamping mechanism are used to support and clamp the connecting rail near the machining area; the workpiece is clamped and aligned, the clamping and alignment including using the bidirectional centering vise to clamp and position the front alloy head, and activating the electro-permanent magnetic chuck to adsorb the front alloy head and the rear connecting rail near the machining area. The heel end connecting rail at the welding position; the spacing of the heel end connecting rail near the welding position is adjusted to the target size using a rail spacing adjustment and fixing device, and the center of the rail spacing width is aligned with the center of the front alloy head; the alignment method includes taking the relatively fixed and high-precision edge of the workbench or the edge of the tooling after cutting and alignment as the reference zero line, using alignment measuring tools to measure the distance of the 16mm outer point of each alignment position rail relative to the reference zero line, and adjusting the lateral tightening screws on both sides for position correction; after alignment, the two connecting rails are pressed together using the clamping mechanism in the connecting rail auxiliary support and clamping mechanism; local pre-milling and working edge milling are completed using a forming milling cutter; the local pre-milling includes single-sided milling in the width direction. With a 2mm allowance, process the working edges of both sides of the front alloy head at the welding area in several passes, and check the step height of the milled surface relative to the connecting rail. If it is relatively uniform, proceed with subsequent milling; if it is not uniform, slightly correct the Y-axis zero point value based on the measurement results until the milled surface on both sides of the front alloy head matches the step height of the corresponding connecting rail. The working edge milling includes using a form milling cutter, according to the Y-axis zero point coordinates adjusted by local pre-milling, to mill the working edges of both sides of the front alloy head in 3-4 passes. The tool path includes entering obliquely from one side of the workpiece, after the flash welding point, to the actual tip according to the drawing line, and then moving the tool to the other side for symmetrical back-turn machining. The cutting tool exits obliquely from the corresponding position of the heel end connecting rail. During the cutting process, after the milling depth covers the local pre-milling position, the step height of the milled surface relative to the heel end connecting rail is measured on the side and top surfaces of each cutting pass, and the cutting values ​​in the Y and Z directions are adjusted accordingly. The Y direction points to the width direction, and the Z direction points to the height direction. When adjusting the Z value, the cutting dimensions on both sides are slightly differentiated according to the actual height of the heel end connecting rail, until the working edge of the front alloy head is smoothly connected to the heel end connecting rail. The milling tool runs close to the surface of the heel end connecting rail head and makes a slight cut. At the weld point, the cutting surface extends inward beyond the center of the top of the heel end connecting rail on the top surface and is 16mm lower than the side of the heel end connecting rail on the side.A face milling cutter is used to remove the step left in the middle area when the form milling cutter is used on both sides. The cutting height during milling is based on being close to the center of the top surface of the working edges on both sides.

2. The processing method for welding mandrels according to claim 1, characterized in that, The track spacing adjustment and fixing device includes fixing bolts, washers, spacers, and forward and reverse adjustment bolts; the alignment measuring tool includes an L-shaped magnetic base, a magnetic switch, a height-direction main scale, a horizontal-direction vernier scale, a horizontal-direction main scale, fastening screws, and a height-direction vernier scale.

3. The processing method for welding mandrels according to claim 1, characterized in that, Before using the machining fixture, the fixture is aligned. The fixture alignment includes cutting alignment using a face milling cutter under the same Z-coordinate of the machine tool and alignment using a bidirectional centering vise.

4. The processing method for welding mandrels according to claim 1, characterized in that, The electro-permanent magnet chuck and the bidirectional centering vise each comprise multiple units and are distributed along the length of the machining fixture.

5. The processing method for welding mandrels according to claim 4, characterized in that, The workpiece clamping surface of the jaws of the bidirectional centering vise is a plane or arc surface used to form point contact.

6. The processing method for welding mandrels according to claim 1, characterized in that, The machining fixture also includes a tail steel structure support.

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