A large I-shaped section non-closed arc-shaped guide rail medium-frequency quenching deformation correction device and method

Abstract

The application discloses a large I-shaped section non-closed arc-shaped guide rail medium-frequency quenching deformation correction device and method, belongs to the technical field of deformation correction, and comprises a connecting rod, a retainer, a protective pad and a pre-tightening screw, the connecting rod is connected with the retainers at both ends, the retainer is internally provided with a square hole capable of accommodating the I-shaped steel section to be inserted, the end of the retainer is provided with a screw hole, the pre-tightening screw is screwed into the hole, and pressure is applied to the track. The application aims at the problem that the large I-shaped section non-closed arc-shaped guide rail is plastically deformed during medium-frequency quenching, resulting in the increase of the diameter of the guide rail, provides a deformation correction method, the operation process of the method is simple, the problem that the machining allowance is insufficient and the surface mechanical properties are insufficient due to the excessive deformation of the guide rail is avoided, the method is suitable for the surface quenching manufacturing and processing field of large non-closed arc-shaped tracks, and is worth promoting. The application has the advantages of simple structure, simple operation process, good deformation correction effect and low cost.

Description

Technical Field

[0001] This invention relates to the field of deformation correction technology, and in particular to a device and method for correcting deformation caused by medium-frequency quenching of a large I-shaped cross-section non-closed arc-shaped guide rail. Background Technology

[0002] Nickel-chromium-molybdenum tempered steel is a high-quality alloy steel with high strength, toughness, good hardenability and stability against overheating. In the tempered state, it is suitable for manufacturing important parts with high strength and large cross-section. It has a high carbon content and a high tendency to harden. If subjected to cyclic loads during use, it is prone to damage[1]. In order to improve this defect of this type of steel, the surface quenching method of medium frequency heating can be used to modify its surface, improve the wear resistance, fatigue resistance and load-bearing capacity of the material surface, and make the material have good comprehensive mechanical properties.

[0003] A large I-shaped cross-section non-closed arc-shaped guide rail ( Figure 1 The guide rail is large in size. After medium frequency quenching, the thermal stress and structural stress caused by thermal expansion and contraction and structural transformation, as well as the residual stress from the previous machining process, are superimposed, causing plastic deformation of the guide rail. The outer diameter of the guide rail increases by 70mm. If no correction measures are taken, the guide rail will be scrapped due to exceeding the tolerance.

[0004] This workpiece has a machining allowance before surface induction hardening, requiring that the diameter deformation after induction hardening not exceed 8mm. The existing deformation already far exceeds this allowance. Excessive machining allowance removes too much hardened layer during processing, leading to reduced surface hardness and wear resistance, severely shortening the part's lifespan. Furthermore, a large machining allowance increases the amount of machining required on high-hardness surfaces, consuming more materials and time, increasing costs, and reducing production efficiency. Therefore, it is necessary to invent a correction method and device for the guide rail after induction hardening to control the deformation within a reasonable range.

[0005] Currently, both domestically and internationally, there are only patents and articles related to medium-frequency quenching technology for closed-loop circular rings of the same material and anti-deformation measures for non-closed-loop arc tempering processes of the same material. There are no patents or articles related to surface medium-frequency quenching deformation correction devices and methods for non-closed large I-shaped cross-section arc-shaped guide rails. Summary of the Invention

[0006] This invention addresses the problem of increased guide rail diameter due to plastic deformation during the surface medium-frequency quenching process of large I-shaped non-closed arc-shaped guide rails. It proposes a deformation correction method and designs a deformation device. While ensuring the surface hardness and hardened layer depth of the part, the method and device correct the guide rail deformation within a reasonable range, avoiding insufficient machining allowance and inadequate surface mechanical properties caused by excessive deformation. This invention is applicable to the manufacturing and processing of large arc-shaped rails through surface quenching and is worthy of promotion.

[0007] To address the aforementioned technical problems, this invention proposes a calibration device and a calibration method, the technical solution of which is as follows.

[0008] A device for correcting deformation of a large I-beam cross-section non-closed arc-shaped guide rail after medium-frequency quenching. The device includes a connecting rod, a retainer, a protective pad, and a pre-tightening screw. The retainer is connected to both ends of the connecting rod. The retainer has a square hole that can accommodate the insertion of the I-beam cross-section. The end of the retainer has a screw hole. The pre-tightening screw is screwed into the hole to apply pressure to the rail.

[0009] Furthermore, a protective pad is inserted into the hole, and the protective pad is installed between the track and the preload screw.

[0010] Furthermore, the guide rail is made of nickel-chromium-molybdenum modulated steel.

[0011] Furthermore, the chord length of the arc is greater than or equal to 8m.

[0012] Furthermore, the forging blank undergoes quenching and tempering treatment, and the surface of the guide rail is subjected to medium-frequency quenching, which is applied to the outer surface of the arc of the guide rail, the middle web of the I-beam, and the inner wall of the outer surface. The surface hardness of the quenched part is greater than or equal to HRC48; the depth of the hardened layer is greater than or equal to 6mm.

[0013] A method for correcting deformation of a large I-shaped cross-section non-closed arc-shaped guide rail surface after medium-frequency quenching, characterized by comprising the following steps:

[0014] Step 1: Measure the outer diameter of the guide rail after surface medium-frequency quenching. The medium-frequency quenching positions are located on the outer surface of the guide rail's arc, the middle web of the I-beam, and the inner wall of the outer surface.

[0015] Step 2: Based on the measurement results of the guide rail outer diameter, calculate the pre-clamping amount required for the guide rail to use the above-mentioned deformation correction device through simulation;

[0016] Step 3: Install the aforementioned deformation correction device, place both ends of the guide rail into the square holes of the retainer, place the protective pad between the pre-tightening bolt and the outer arc surface of the guide rail, and tighten the pre-tightening bolt to pre-tighten the guide rail according to the simulation calculation results in Step 2.

[0017] Step 4: Perform reverse deformation medium-frequency quenching on the inner arc surface of the guide rail;

[0018] Step 5: Perform tempering heat treatment on the guide rail. During this process, the deformation correction device is not removed.

[0019] Step 6: Remove the deformation correction device and remeasure the outer diameter of the guide rail.

[0020] Compared with existing technologies, this invention addresses the problem of increased guide rail diameter due to plastic deformation during medium-frequency quenching of large I-shaped cross-section non-closed arc-shaped guide rails. It provides a deformation correction method with a simple operation process, avoiding insufficient machining allowance and inadequate surface mechanical properties caused by excessive guide rail deformation. It is applicable to the manufacturing and processing of large non-closed arc-shaped rails and is worthy of promotion.

[0021] 2. This invention provides a deformation correction device that applies this deformation correction method; it has a simple structure, simple operation process, good deformation correction effect, and low cost. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a large I-shaped cross-section non-closed arc-shaped guide rail;

[0023] Figure 2 This is a schematic diagram showing the location of the surface of the I-shaped cross-section guide rail that requires medium-frequency quenching;

[0024] Figure 3 This is a diagram of a guide rail surface medium-frequency quenching deformation correction device;

[0025] Figure 4 This is a schematic diagram of the quenching position on the inner arc surface of the guide rail in the reverse deformation direction;

[0026] Figure 5 This is a schematic diagram of a guide rail deformation correction device;

[0027] Figure 6 This is an enlarged schematic diagram of the guide rail deformation correction device.

[0028] Where A is the outer surface of the arc, D and E are the webs of the I-beam, B and C are the inner walls of the outer surface, and F is the inner surface of the arc. 1 is the I-beam, 2 is the straightening device, 2-1 is the connecting rod, 2-2 is the retainer, 2-3 is the protective pad, and 2-4 is the preload screw. Detailed Implementation

[0029] The technical solution of the present invention will be further explained below with reference to the accompanying drawings.

[0030] The object involved is a large, non-closed arc-shaped guide rail with an I-shaped cross-section, such as... Figure 1As shown, the guide rail has a non-closed circular arc shape and an I-shaped cross-section; as Figure 2 As shown, the guide rail has surfaces A, B, C, D, and E that undergo medium-frequency quenching. After medium-frequency quenching at these five surfaces, the distance between the two ends of the semi-circular guide rail increases under the quenching stress, causing the outer diameter of the guide rail to increase beyond reasonable requirements.

[0031] To address the deformation problem of the guide rails after medium-frequency quenching, this invention designs a deformation correction device 2, see... Figure 3 It is installed on both ends of guide rail 1. The deformation correction device applies pressure to both ends of the guide rail, causing elastic deformation and generating outward elastic stress inside the guide rail. Based on this, the inner arc surface of the guide rail is subjected to reverse deformation medium-frequency quenching F, see Figure 4 Under the influence of temperature, the material near the inner arc surface of the guide rail undergoes a phase transformation, and the elastic stress near the inner arc surface of the guide rail disappears, changing from elastic deformation to plastic deformation. During the medium-frequency quenching and cooling process of the inner arc surface of the guide rail, the temperature of the inner arc surface of the guide rail drops sharply, generating internal stress. Under the action of internal stress, the inner arc surface of the guide rail undergoes shrinkage deformation. The shrinkage internal stress generated by the quenching of the inner arc surface of the guide rail is balanced with the outward expansion elastic stress of the guide rail. After removing the deformation correction device, the outer diameter of the guide rail stabilizes within a reasonable size, thereby achieving the correction purpose.

[0032] The specific structure of a medium-frequency quenching deformation correction device for a large I-shaped cross-section non-closed arc-shaped guide rail is shown below. Figure 5 , Figure 6 It includes a connecting rod 2-1, a retainer 2-2, a fixing baffle 2-3, a protective pad 2-4, and a pre-tightening bolt 2-5.

[0033] To achieve the pre-tightening effect of the above-mentioned deformation correction device on both ends of the guide rail, the two ends of the guide rail are placed in the two square frames of the retainer 2-2, and the protective pad 2-3 is placed between the pre-tightening bolt 2-4 and the outer arc surface of the guide rail. The retainer 2-2 and both ends of the guide rail are connected and fixed by the connecting rod 2-1. When the pre-tightening bolt 2-4 is tightened, the pre-tightening bolt applies pressure to the guide rail through the protective pad. Under the pressure at both ends, the guide rail undergoes shrinkage deformation, and the outer diameter of the guide rail shrinks and becomes smaller under the deformation correction device.

[0034] When using it, the following steps are included:

[0035] Step 1: Measure the outer diameter of the guide rail after completing the medium-frequency quenching of 5 surfaces;

[0036] Step 2: Based on the measurement results of the guide rail outer diameter, calculate the pre-clamping amount required for the guide rail to use the above-mentioned deformation correction device through simulation;

[0037] Step 3: Install the above deformation correction device, place both ends of the guide rail in the two square frames of the retainer 2-2, place the protective pad 2-3 between the pre-tightening bolt 2-4 and the outer arc surface of the guide rail, and tighten the pre-tightening bolt 2-4. Adjust the pre-tightening bolt 2-4 to pre-tighten the guide rail according to the simulation calculation results in Step 2.

[0038] Step 4: Perform reverse deformation medium-frequency quenching on the inner arc surface of the guide rail;

[0039] Step 5: Perform tempering heat treatment on the guide rail. During this process, the aforementioned deformation correction device shall not be removed.

[0040] Step 6: Remove the above deformation correction device and remeasure the outer diameter of the guide rail.

Claims

1. A surface medium frequency quenching deformation correction method for a large I-shaped section non-closed arc-shaped guide rail, characterized in that, It comprises the following steps: Step one: measure the outer diameter of the guide rail after the surface medium frequency quenching, the medium frequency quenching position is respectively located in the outer surface of the guide rail arc, the I-beam middle web and the inner wall part of the outer surface; Step two: according to the guide rail outer diameter measurement result, the pre-pressing amount required for the guide rail to adopt the deformation correction device is calculated through simulation; the deformation correction device comprises a connecting rod, a retainer, a protective pad and a pre-tightening screw, the connecting rod is connected with the retainer at both ends, the retainer has a square hole capable of accommodating the I-beam cross section inserted, the end of the retainer has a screw hole, the pre-tightening screw is screwed into the screw hole, and the guide rail is subjected to pressure; Step three: install the deformation correction device, place the guide rail end in the square hole of the retainer, place the protective pad between the pre-tightening screw and the outer arc surface of the guide rail, and tighten the pre-tightening screw according to the simulation calculation result in step two to pre-press the guide rail; Step four: reverse deformation medium frequency quenching is carried out on the inner side arc surface of the guide rail; Step five: the guide rail is subjected to tempering heat treatment, and the deformation correction device is not removed during the process; Step six: remove the deformation correction device and re-measure the outer diameter of the guide rail.

2. The surface quenching and deformation correction method of the large H-shaped section open arc guide rail according to claim 1, characterized in that, The protective pad is inserted into the square hole, and the protective pad is installed between the guide rail and the pre-tightening screw.

3. The surface quenching and deformation correction method of the large H-shaped section open arc guide rail according to claim 1, characterized in that, The guide rail adopts nickel-chromium-molybdenum alloy steel.

4. The surface quenching and deformation correction method of the large H-shaped section open arc guide rail according to claim 1, characterized in that, The chord length of the arc is greater than or equal to 8m.

5. The surface quenching and deformation correction method of the large H-shaped section open arc guide rail according to claim 1, characterized in that, The forging blank adopts quenching and tempering treatment, the surface of the guide rail part adopts medium frequency quenching, which is respectively located in the outer surface of the guide rail arc, the I-beam middle web and the inner wall part of the outer surface, and the surface hardness of the quenched surface is greater than or equal to HRC48; the hardened layer depth of the quenched surface is greater than or equal to 6mm.

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