Method for designing flow guide tool and reducing heat treatment deformation of workpiece based on finite element method

Abstract

The invention relates to a method for reducing heat treatment deformation of a workpiece, in particular to a method for designing a flow guide tool based on a finite element method to reduce heat treatment deformation of the workpiece. The problem that in the prior art, a bearing ring deforms under the combined action of thermal stress and structural stress after heat treatment is solved. Finite element software is used for simulating and calculating flow field distribution in a vacuum gas quenching furnace, then the flow field distribution is regulated and controlled through a beam tool, the position and the hole diameter of a hole formed in the flow guide tool are optimized based on the simulation calculation result of the finite element software, and the flow field near a bearing ring is evenly distributed; the beam tool design is guided through a simulation means, time and cost are saved, and heat treatment deformation of the bearing ring is reduced. The invention belongs to the technical field of workpiece heat treatment deformation reduction.

Description

Technical Field

[0001] This invention relates to a method for reducing workpiece deformation during heat treatment, specifically a method for designing a flow guiding fixture based on the finite element method to reduce workpiece deformation during heat treatment, belonging to the technical field of reducing workpiece deformation during heat treatment. Background Technology

[0002] Bearings, as an indispensable core component in mechanical equipment, are often referred to as the "joints of the machinery industry." Their performance directly affects the precision, stability, reliability, and service life of the entire mechanical equipment. Whether in civilian fields such as precision machine tools, automobile engines, and rail vehicles, or in cutting-edge industrial fields such as high-end equipment manufacturing, bearings play a crucial role in supporting rotating shafts, reducing kinetic friction, and transmitting loads.

[0003] In the machining process of bearing rings, heat treatment is the core process that endows them with excellent mechanical properties. Through vacuum quenching heat treatment, the hardness, strength, wear resistance and fatigue resistance of the rings can be significantly improved, meeting their service requirements under complex working conditions. However, during vacuum quenching, the bearing rings are inevitably subjected to the combined action of thermal stress and structural stress, which leads to deformation. This problem has become an important bottleneck restricting the machining accuracy and performance stability of bearing rings.

[0004] Currently, solving heat treatment deformation through experimental methods is time-consuming and costly, making it difficult to promote and implement.

[0005] In summary, how to propose a method to reduce workpiece deformation during heat treatment in response to the above-mentioned technical problems has become an urgent issue for those skilled in the art. Summary of the Invention

[0006] To address the shortcomings of the prior art, this invention provides a method for designing flow guiding fixtures based on the finite element method to reduce workpiece deformation during heat treatment.

[0007] The technical solution of this invention is: a method for reducing workpiece heat treatment deformation by designing a flow guiding fixture based on the finite element method, specifically carried out according to the following steps:

[0008] Step 1: Establish the model used for calculation

[0009] Step 1: Measure the furnace chamber dimensions of the vacuum air quenching furnace;

[0010] Step 12: Establish a three-dimensional model of the vacuum quenching furnace, and draw the furnace air inlet and outlet in the three-dimensional model;

[0011] Step 13: Draw the geometric models of the bearing rings and the material frame within the 3D model of the vacuum quenching furnace to obtain the model used for calculation;

[0012] Step 2: Import the model obtained in Steps 1 and 3 into the finite element software for calculation;

[0013] Step 2: Assign material properties to the model;

[0014] Step 22: Mesh the model;

[0015] Steps 2 and 3: Use the turbulence model in the software to calculate the flow field and obtain the longitudinal distribution map of the flow field during the air quenching cooling process;

[0016] Step 24: Export the flow field distribution diagram of the bearing ring at the top layer bearing ring. Optimize the opening position and diameter of the flow guiding tool based on the flow field distribution diagram to obtain the optimized flow guiding tool.

[0017] Step 3: First, based on the optimized flow guiding fixture in Step 3, process the flow beam fixture using 304 stainless steel material, and then install the flow beam fixture into the vacuum quenching furnace, with the distance between the flow beam fixture and the furnace outlet being 90-110mm.

[0018] Step 4: Perform heat treatment

[0019] After heating, the bearing rings are quenched with nitrogen gas at a temperature of 5–15°C and a pressure of 1.5–2.5 bar. This completes the method of reducing workpiece heat treatment deformation by designing a flow guiding fixture based on the finite element method.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. This invention utilizes finite element software to simulate and calculate the flow field distribution within a vacuum air quenching furnace, and then uses a beam tooling to control the flow field distribution. Based on the simulation results of the finite element software, the position and diameter of the opening of the flow guiding tooling are optimized to ensure a uniform flow field distribution near the bearing ring. The simulation method guides the design of the beam tooling, saving time and costs and reducing the deformation of the bearing ring during heat treatment. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the model used in the calculation;

[0023] Figure 2 This is a longitudinal distribution diagram of the flow field during the air quenching process. The units of the values ​​in the diagram are m / s.

[0024] Figure 3 This is a lateral flow field distribution diagram of the uppermost bearing ring during the air quenching cooling process. The units of the values ​​in the diagram are m / s.

[0025] Figure 4 This is a schematic diagram of the optimized flow guide tooling dimensions. The values ​​in the diagram are in mm.

[0026] Figure 5 This is a lateral flow field distribution diagram of the uppermost bearing ring after the flow guiding fixture is installed. The units of the values ​​in the diagram are m / s.

[0027] Figure 6 This is a schematic diagram of the deformation of the bearing ring before the installation of the guide fixture. The units of the values ​​in the diagram are mm.

[0028] Figure 7 This is a schematic diagram showing the deformation of the bearing rings after the installation of the flow guide fixture. The values ​​in the diagram are in mm. Detailed Implementation

[0029] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments.

[0030] Specific implementation method one: Combining Figures 1 to 7 This embodiment describes a method for designing a flow-guiding fixture based on the finite element method to reduce workpiece deformation during heat treatment. The specific steps are as follows:

[0031] Step 1: Establish the model used for calculation

[0032] Step 1: Measure the furnace chamber dimensions of the vacuum gas quenching furnace. The vacuum gas quenching furnace is a Turbo Treater type vacuum gas quenching furnace manufactured by Ipsen GmbH, Germany.

[0033] Step 12: Establish a three-dimensional model of the vacuum quenching furnace, and draw the furnace air inlet and outlet in the three-dimensional model;

[0034] Step 13: Draw the geometric models of the bearing rings and the material frame within the 3D model of the vacuum quenching furnace to obtain the model used for calculation;

[0035] Step 2: Import the model obtained in Steps 1 and 3 into the finite element software for calculation;

[0036] Step 2: Assign material properties to the model;

[0037] Step 22: Mesh the model;

[0038] Steps 2 and 3: Use the turbulence model (k-ω model) in the CFD module of the software to calculate the flow field and obtain the longitudinal distribution map of the flow field during the air quenching cooling process;

[0039] Step 24: Export the flow field distribution diagram of the bearing ring at the top layer (near the air inlet). Optimize the opening position and diameter of the flow guiding tool based on the flow field distribution diagram to obtain the optimized flow guiding tool.

[0040] The longitudinal distribution of the flow field during the air quenching cooling process calculated above is shown in the figure. Figure 2 The lateral distribution of the flow field near the uppermost bearing ring is shown in the figure. Figure 3 By changing the opening scheme on the flow guiding tool, the spatial flow field distribution inside the furnace can be adjusted. Through multiple numerical simulations in the software, the influence of the opening position and aperture size of the flow beam baffle on the spatial velocity distribution can be found.

[0041] The calculations revealed that the orifice location affects the flow velocity uniformity, while the orifice size affects the flow velocity below the guide fixture. By designing an orifice scheme, calculating the flow field distribution around the collar, and then adjusting the orifice location based on flow field feedback, the process was repeated until the most suitable orifice scheme was found. The optimized beam fixture dimensions and structure are as follows: Figure 4 As shown.

[0042] Step 3: First, based on the optimized flow guiding fixture in Step 3, process the flow beam fixture using 304 stainless steel material, and then install the flow beam fixture into the vacuum quenching furnace, with the distance between the flow beam fixture and the furnace outlet being 90-110mm.

[0043] Step 4: Perform heat treatment

[0044] After heating, the bearing rings are quenched with nitrogen gas at a temperature of 5–15°C and a pressure of 1.5–2.5 bar. This completes the method of reducing workpiece heat treatment deformation by designing a flow guiding fixture based on the finite element method.

[0045] Based on the above steps, the flow field distribution near the bearing race after installing the flow guiding fixture was calculated (see...). Figure 5 This ensures a uniform flow field distribution around the bearing race; and calculations show that the maximum deformation of the bearing race after heat treatment before installing the flow guide fixture is 0.021 mm (see...). Figure 6 The maximum deformation after installing the flow guide fixture is 0.0205 mm (see...). Figure 7 Therefore, the flow guiding fixture designed based on the finite element method improves the uniformity of the flow field distribution in the vacuum quenching furnace and reduces the deformation of the bearing rings after heat treatment.

[0046] Specific Implementation Method Two: Combining Figures 1 to 7 This embodiment describes how AutoCAD software is used to create the model in step one.

[0047] Furthermore, in step two, COMSOL software is used for calculation.

[0048] Furthermore, in step three, the distance between the beam fixture and the furnace outlet is 100mm.

[0049] Furthermore, the temperature of the nitrogen gas in step four is 10°C.

[0050] Furthermore, the nitrogen pressure in step four is 2 bar.

[0051] The other components and connections are the same as in Specific Implementation Method 1.

[0052] The present invention has been disclosed above with reference to preferred embodiments, but it is not intended to limit the present invention. Any simple modifications, equivalent changes and alterations made by those skilled in the art to the above embodiments without departing from the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for designing flow guiding fixtures based on the finite element method to reduce workpiece heat treatment deformation, characterized in that: This method is specifically carried out in the following steps: Step 1: Establish the model used for calculation Step 1: Measure the furnace chamber dimensions of the vacuum air quenching furnace; Step 12: Establish a three-dimensional model of the vacuum quenching furnace, and draw the furnace air inlet and outlet in the three-dimensional model; Step 13: Draw the geometric models of the bearing rings and the material frame within the 3D model of the vacuum quenching furnace to obtain the model used for calculation; Step 2: Import the model obtained in Steps 1 and 3 into the finite element software for calculation; Step 2: Assign material properties to the model; Step 22: Mesh the model; Steps 2 and 3: Use the turbulence model in the software to calculate the flow field and obtain the longitudinal distribution map of the flow field during the air quenching cooling process; Step 24: Export the flow field distribution diagram of the bearing ring at the top layer bearing ring. Optimize the opening position and diameter of the flow guiding tool based on the flow field distribution diagram to obtain the optimized flow guiding tool. Step 3: First, based on the optimized flow guiding fixture in Step 3, process the flow beam fixture using 304 stainless steel material. Then the beam fixture is installed inside the vacuum quenching furnace, and the distance between the beam fixture and the furnace outlet is 90-110mm. Step 4: Perform heat treatment After heating, the bearing rings are quenched with nitrogen gas at a temperature of 5–15°C and a pressure of 1.5–2.5 bar. This completes the method of reducing workpiece heat treatment deformation by designing a flow guiding fixture based on the finite element method.

2. The method for reducing workpiece heat treatment deformation by designing a flow guiding fixture based on the finite element method according to claim 1, characterized in that: In step one, AutoCAD software is used to build the model.

3. The method for reducing workpiece heat treatment deformation by designing a flow guiding fixture based on the finite element method according to claim 2, characterized in that: In step two, COMSOL software is used for calculation.

4. The method for reducing workpiece heat treatment deformation by designing a flow-guiding fixture based on the finite element method according to claim 3, characterized in that: In step three, the distance between the beam fixture and the furnace outlet is 100mm.

5. The method for reducing workpiece heat treatment deformation by designing a flow guiding fixture based on the finite element method according to claim 4, characterized in that: The temperature of the nitrogen gas in step four is 10°C.

6. The method for reducing workpiece heat treatment deformation by designing a flow guiding fixture based on the finite element method according to claim 5, characterized in that: The nitrogen pressure in step four is 2 bar.

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