Induction quenching and tempering method for main bearing ring and obtained product

Abstract

The invention relates to the technical field of heat treatment of main bearing rings, in particular to a main bearing ring induction quenching and tempering method and an obtained product. The product is prepared by the method. The method comprises the steps of installing a workpiece; installing a first sensor and a second sensor; quenching parameters are set, and induction quenching treatment on the current to-be-quenched surface of the workpiece is completed; tempering parameters are set, and induction tempering treatment on the current to-be-quenched face of the workpiece is completed; spray cooling treatment on the workpiece is further included between the induction quenching treatment and the induction tempering treatment. And the induction quenching treatment and the induction tempering treatment are combined to complete quenching and tempering operation on the next to-be-quenched surface of the workpiece in sequence, and so on, until quenching and tempering operation on all to-be-quenched surfaces of the workpiece is completed. The method can solve the problems of low production efficiency, high energy consumption and high cost caused by timely tempering in the existing surface quenching treatment mode.

Description

Technical Field

[0001] The invention relates to the technical field of heat treatment of a main bearing ring, and in particular to an induction quenching and tempering method for a main bearing ring and a resulting product. Background Art

[0002] As the core component of the shield machine, the main bearing has the characteristics of high load-bearing capacity, high price and difficult replacement. As the main component of the shield machine main bearing, the ring needs to be quenched on its raceway and flange to increase the surface hardness of the ring and thus increase its fatigue life.

[0003] At present, the surface quenching treatment method is generally used for the raceway and flange of the main bearing ring, specifically the scanning surface quenching method; after the quenching is completed, it is necessary to temper in time (this tempering is conventional tempering, that is, the single tempering time is usually 7~15h, and the single tempering requires nearly 10,000 yuan in electricity); if the tempering is not timely, cracks may appear on the surface, which will cause the ring to be scrapped. The ring is expensive, costing hundreds of thousands or millions. If cracks occur, it will cause great economic losses. In addition, because the ring generally has 3~5 quenching surfaces, if the surface is tempered in time after each quenching, it will need to be tempered multiple times; if the ring is heat treated in this way, not only will the production efficiency be low, manpower will be wasted, but also a large amount of energy will be consumed, increasing production costs.

[0004] In order to solve the above problems, it is necessary to develop a main bearing ring induction quenching and tempering method and the resulting product to solve the problems of low production efficiency, high energy consumption and high cost caused by the need for timely tempering in the existing surface quenching treatment method. Summary of the invention

[0005] The object of the present invention is to provide a method for induction quenching and tempering of a main bearing ring and the resulting product. The specific technical scheme is as follows: In a first aspect, the present invention provides a method for induction quenching and tempering of a main bearing ring, comprising: Step S1, installing the workpiece; hoisting the workpiece onto the workbench of the quenching machine, aligning the workpiece and clamping the workpiece; Step S2, installing a first sensor and a second sensor; sequentially arranging the first sensor and the second sensor along the rotation direction of the workpiece; Step S3, setting quenching parameters and completing the induction quenching treatment of the current surface of the workpiece to be quenched; setting the speed of the worktable to rotate the workpiece in linkage with the workpiece on the quenching machine to be 100-200 mm / min; setting the working power of the first inductor and the second inductor to be 60-80 kW; setting the working frequency of the first inductor and the second inductor to be 2.0-4.0 kHz; setting the coupling gap between the first inductor and the workpiece and the coupling gap between the second inductor and the workpiece to be 2-4 mm; after setting the quenching parameters, starting the quenching machine, the first inductor and the second inductor to complete the induction quenching treatment of the current surface of the workpiece to be quenched; Step S4, setting tempering parameters and completing the induction tempering treatment of the current surface to be quenched of the workpiece; setting the speed of the worktable linked to the workpiece rotation on the quenching machine to 80-140 mm / min; setting the working power of the first sensor and the second sensor to 20-35 kW; setting the working frequency of the first sensor and the second sensor to 1.0-2.0 kHz; setting the coupling gap between the first sensor and the workpiece and the coupling gap between the second sensor and the workpiece to 2-4 mm; after setting the tempering parameters, starting the quenching machine, the first sensor and the second sensor to complete the induction tempering treatment of the current surface to be quenched of the workpiece; A spray cooling process is also included for the workpiece between the induction hardening process and the induction tempering process; Step S5, combining the induction hardening treatment and the induction tempering treatment to sequentially complete the quenching and tempering operations on the next surface to be quenched of the workpiece, and so on, until the quenching and tempering operations on all surfaces to be quenched of the workpiece are completed.

[0006] Optionally, the cooling liquid used in the spray cooling treatment includes PAG quenching liquid; the mass concentration of the PAG quenching liquid used is 10%~15%, and the flow rate is 60~70L / min.

[0007] Optionally, the spraying method adopted in the spray cooling treatment is a jetting method.

[0008] Optionally, the spraying method is completed by using a spray box; along the rotation direction of the workpiece, the spray box is arranged behind the second sensor, and an inclined spray hole is arranged on the spray box; the inclination direction of the spray hole deviates from the setting of the second sensor, and the angle between the inclination direction and the surface of the workpiece is 10°~60°.

[0009] Optionally, the first inductor and the second inductor have the same structure, both comprising a magnetic conductor and an induction coil; the magnetic conductor is a rectangular structure with an opening; the induction coil is a hollow copper rectangular tube; the magnetic conductor is integrally embedded in the induction coil.

[0010] Optionally, the induction hardening treatment and the induction tempering treatment further include a cyclic cooling treatment of the first inductor and the second inductor.

[0011] Optionally, the circulating cooling process includes introducing circulating cooling water into the induction coil.

[0012] Optionally, the workpiece is a main bearing ring.

[0013] In a second aspect, the present invention provides a product prepared by the main bearing ring induction quenching and tempering method.

[0014] Optionally, the average depth of the middle hardened layer of the raceway of the product is 9.7~10.1mm, the average surface hardness after quenching is 60.9~61.3HRC, and the average surface hardness after tempering is 60.3~60.8HRC.

[0015] The application of the technical solution of the present invention has at least the following beneficial effects: (1) The induction quenching and tempering method for the main bearing ring provided by the present invention can solve the problems of low production efficiency, high energy consumption and high cost caused by the need for timely tempering in the existing surface quenching treatment method. Specifically, the present invention first combines induction quenching treatment and induction tempering treatment to sequentially complete the quenching and tempering operations of the current surface to be quenched of the workpiece, and then combines induction quenching treatment and induction tempering treatment to sequentially complete the quenching and tempering operations of the next surface to be quenched of the workpiece, and so on, until the quenching and tempering operations of all surfaces to be quenched of the workpiece are completed; finally, the workpiece is transferred to the tempering furnace for final tempering (i.e., conventional tempering in the background technology), which can reduce the overall tempering time by N-1 times, where N is the number of surfaces to be quenched, which saves the total tempering time, not only greatly improves the production efficiency, but also greatly reduces energy consumption and production costs. In addition, compared with induction quenching treatment, the present invention appropriately reduces the rotation speed of the workpiece during induction tempering treatment, which is convenient for increasing the tempering time per unit length of the workpiece, and the working frequency during tempering is lower than the working frequency during quenching, which is convenient for utilizing the skin effect, that is, the low-frequency induced current can penetrate deeper, making the tempering depth deeper and reducing the risk of cracks in the ring.

[0016] (2) The average depth of the middle hardened layer of the raceway of the main bearing ring product prepared by the present invention is 9.7-10.1 mm, the average surface hardness after quenching is 60.9-61.3 HRC, and the average surface hardness after tempering is 60.3-60.8 HRC, which is convenient for reducing the risk of cracks in the ring.

[0017] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 It is a structural schematic diagram of a main bearing ring induction quenching and tempering method in embodiment 1 of the present invention; Figure 2 It is a schematic diagram of the structure of the magnetic conductor; Figure 3 It is a schematic diagram of the structure of the induction coil; Among them, 1, workpiece, 2, first sensor, 3, second sensor, A1, magnetic conductor, A2, induction coil. DETAILED DESCRIPTION

[0019] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention. Embodiment 1:

[0020] See also Figure 1 , a method for induction quenching and tempering of a main bearing ring, comprising: Step S1, installing a workpiece 1 (specifically, a main bearing ring, provided by China Railway Construction Heavy Industry Group Co., Ltd.); hoisting the workpiece 1 onto a workbench of a quenching machine, aligning the workpiece 1 (specifically, adjusting the center of the workpiece 1 to coincide with the center of the workbench), and then clamping the workpiece 1; Step S2, installing the first sensor 2 and the second sensor 3; sequentially arranging the first sensor 2 and the second sensor 3 along the rotation direction of the workpiece 1; Step S3, setting quenching parameters and completing the induction quenching treatment of the current surface to be quenched of the workpiece 1; setting the speed of the worktable to rotate the workpiece 1 in linkage with the workpiece 1 on the quenching machine to 100-200 mm / min (specifically 110 mm / min); setting the working power of the first inductor 2 and the second inductor 3 to 60-80 kW (specifically 74 kW); setting the working frequency of the first inductor 2 and the second inductor 3 to 2.0-4.0 kHz (specifically 2.7 kHz); setting the coupling gap between the first inductor 2 and the workpiece 1 and the coupling gap between the second inductor 3 and the workpiece 1 to 2-4 mm (specifically 2.5 mm); wherein the coupling gap between the first inductor 2 and the workpiece 1 is the distance between the first inductor 2 and the workpiece 1; the coupling gap between the second inductor 3 and the workpiece 1 is the distance between the second inductor 3 and the workpiece 1; after setting the quenching parameters, starting the quenching machine, the first inductor 2 and the second inductor 3 to complete the induction quenching treatment of the current surface to be quenched of the workpiece 1; Step S4, setting tempering parameters and completing the induction tempering treatment of the current surface to be quenched of the workpiece 1; setting the speed of the worktable to rotate the workpiece 1 in linkage with the workpiece 1 to 80-140 mm / min (specifically 90 mm / min) on the quenching machine; setting the working power of the first inductor 2 and the second inductor 3 to 20-35 kW (specifically 26 kW); setting the working frequency of the first inductor 2 and the second inductor 3 to 1.0-2.0 kHz (specifically 1.2 kHz); setting the coupling gap between the first inductor 2 and the workpiece 1 and the coupling gap between the second inductor 3 and the workpiece 1 to 2-4 mm (specifically 2.5 mm); after setting the tempering parameters, starting the quenching machine, the first inductor 2 and the second inductor 3 to complete the induction tempering treatment of the current surface to be quenched of the workpiece 1; A spray cooling process is also included for the workpiece 1 between the induction hardening process and the induction tempering process; Step S5, combining the induction hardening treatment and the induction tempering treatment to sequentially complete the quenching and tempering operations on the next surface to be quenched of the workpiece 1, and so on, until the quenching and tempering operations on all surfaces to be quenched of the workpiece 1 are completed.

[0021] The cooling liquid used in the spray cooling treatment includes PAG quenching liquid; the mass concentration of the PAG quenching liquid used is 10%~15% (specifically 14%), and the flow rate is 60~70L / min (specifically 67L / min).

[0022] The spraying method adopted in the spray cooling treatment is a jetting method.

[0023] The spraying method is completed by using a spray box; along the rotation direction of the workpiece 1, the spray box is arranged behind the second sensor 3, and an inclined spray hole is arranged on the spray box; the inclined direction of the spray hole deviates from the setting of the second sensor 3, and the angle between the inclined direction and the surface of the workpiece is 10°~60° (specifically 25°).

[0024] See also Figure 1-Figure 3 The first inductor 2 and the second inductor 3 have the same structure, both of which include a magnetic conductor A1 (specifically, the American FLUXTROL A type solid magnetic conductor A1 is adopted, and is milled by a CNC machine tool) and an induction coil A2; the magnetic conductor A1 is a rectangular structure with an opening; the induction coil A2 is a hollow copper rectangular square tube; the magnetic conductor A1 is integrally embedded in the induction coil A2, which is convenient for concentrating magnetic flux lines and improving the heating efficiency of the induction coil A2. In addition, compared with traditional silicon steel sheets, the milled magnetic conductor A1 can cover the induction coil A2 with the largest area, and the induction heating efficiency is higher.

[0025] The induction hardening treatment and the induction tempering treatment further include a cyclic cooling treatment of the first inductor 2 and the second inductor 3 .

[0026] The circulating cooling treatment includes passing circulating cooling water into the induction coil A2 to cool the heat on the first inductor 2 and the second inductor 3 themselves during electromagnetic induction heating and the heat radiated from the workpiece 1 to the first inductor 2 and the second inductor 3. Embodiment 2:

[0027] Different from Example 1, some quenching parameters and some tempering parameters are changed; specifically, in the quenching parameters, the working powers of the first inductor 2 and the second inductor 3 are set to 77 kW, and the coupling gap between the first inductor 2 and the workpiece 1 and the coupling gap between the second inductor 3 and the workpiece 1 are set to 2.7 mm; in the tempering parameters, the working powers of the first inductor 2 and the second inductor 3 are set to 29 kW.

[0028] The main bearing ring products treated in Example 1-2 were respectively subjected to the test of the depth of the hardened layer in the middle of the raceway, the surface hardness after quenching, the surface hardness after tempering and the magnetic particle flaw detection test, and the test results are shown in Table 1. Among them, the test of the depth of the hardened layer in the middle of the raceway was tested by sisco.kobelco hardening layer depth measuring instrument (model Kobelco SH-67), 100 test points were randomly selected, and the test results were taken as the average of each test point. The surface hardness test after quenching was tested by Leeb hardness tester (model TIME5301), 100 test points were randomly selected, and the test results were taken as the average of each test point. The surface hardness test after tempering was tested by Leeb hardness tester (model TIME5301), 100 test points were randomly selected, and the test results were taken as the average of each test point.

[0029] Table 1 Hardened layer depth and hardness test results

[0030] From the data in Table 1, we know that: The average depth of the middle hardened layer of the raceway of the main bearing ring products prepared by Examples 1-2 of the present invention is 9.7 mm and 10.1 mm respectively, the average surface hardness after quenching is 61.3 HRC and 60.9 HRC respectively, and the average surface hardness after tempering is 60.8 HRC and 60.5 HRC respectively, which is convenient for reducing the risk of cracks in the ring; and the magnetic particle flaw detection test also proves that the surface of the main bearing ring products prepared by Examples 1-2 is free of cracks.

[0031] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for induction quenching and tempering of a main bearing ring, characterized in that: include: Step S1, installing the workpiece; hoisting the workpiece onto the workbench of the quenching machine, aligning the workpiece and clamping the workpiece; Step S2, installing a first sensor and a second sensor; sequentially arranging the first sensor and the second sensor along the rotation direction of the workpiece; Step S3, setting quenching parameters and completing the induction quenching treatment of the current surface of the workpiece to be quenched; setting the speed of the worktable to rotate the workpiece in linkage with the workpiece on the quenching machine to be 100-200 mm / min; setting the working power of the first inductor and the second inductor to be 60-80 kW; setting the working frequency of the first inductor and the second inductor to be 2.0-4.0 kHz; setting the coupling gap between the first inductor and the workpiece and the coupling gap between the second inductor and the workpiece to be 2-4 mm; after setting the quenching parameters, starting the quenching machine, the first inductor and the second inductor to complete the induction quenching treatment of the current surface of the workpiece to be quenched; Step S4, setting tempering parameters and completing the induction tempering treatment of the current surface to be quenched of the workpiece; setting the speed of the worktable linked to the workpiece rotation on the quenching machine to 80-140 mm / min; setting the working power of the first sensor and the second sensor to 20-35 kW; setting the working frequency of the first sensor and the second sensor to 1.0-2.0 kHz; setting the coupling gap between the first sensor and the workpiece and the coupling gap between the second sensor and the workpiece to 2-4 mm; after setting the tempering parameters, starting the quenching machine, the first sensor and the second sensor to complete the induction tempering treatment of the current surface to be quenched of the workpiece; A spray cooling process is also included for the workpiece between the induction hardening process and the induction tempering process; Step S5, combining the induction hardening treatment and the induction tempering treatment to sequentially complete the quenching and tempering operations on the next surface to be quenched of the workpiece, and so on, until the quenching and tempering operations on all surfaces to be quenched of the workpiece are completed.

2. The method for induction quenching and tempering of a main bearing ring according to claim 1, characterized in that: The cooling liquid used in the spray cooling treatment includes PAG quenching liquid; the mass concentration of the PAG quenching liquid used is 10%~15%, and the flow rate is 60~70L / min.

3. The method for induction quenching and tempering of a main bearing ring according to claim 1, characterized in that: The spraying method adopted in the spray cooling treatment is a jetting method.

4. The method for induction quenching and tempering of a main bearing ring according to claim 3, characterized in that: The spraying method is completed by using a spray box; along the rotation direction of the workpiece, the spray box is arranged behind the second sensor, and an inclined spray hole is arranged on the spray box; the inclined direction of the spray hole deviates from the setting of the second sensor, and the angle between the inclined direction and the surface of the workpiece is 10°~60°.

5. The induction quenching and tempering method for the main bearing ring according to any one of claims 1 to 4, characterized in that: The first inductor and the second inductor have the same structure, both of which include a magnetic conductor and an induction coil; the magnetic conductor is a rectangular structure with an opening; the induction coil is a hollow copper rectangular square tube; the magnetic conductor is integrally embedded in the induction coil.

6. The method for induction quenching and tempering of a main bearing ring according to claim 5, characterized in that: The induction hardening process and the induction tempering process further include a cyclic cooling process performed on the first inductor and the second inductor.

7. The method for induction quenching and tempering of a main bearing ring according to claim 6, characterized in that: The circulating cooling process includes introducing circulating cooling water into the induction coil.

8. The method for induction quenching and tempering of a main bearing ring according to claim 7, characterized in that: The workpiece is a main bearing ring.

9. A product prepared by the induction quenching and tempering method for a main bearing ring as claimed in claim 8.

10. The product according to claim 9, characterized in that The average depth of the middle hardened layer of the raceway of the product is 9.7~10.1mm, the average surface hardness after quenching is 60.9~61.3HRC, and the average surface hardness after tempering is 60.3~60.8HRC.

Images