A method for reducing the heat treatment deformation of long rod parts

Abstract

The invention discloses a method for reducing the heat treatment deformation of long rod parts, and relates to the field of heat treatment processing technology. The steps are as follows: S01. preparing tooling, S02. assembling tooling, S03. positioning and straightening, S04. placing parts, S05. fixing parts, S06. heat treatment, and S07. cooling and inspection. By adopting the tooling of this scheme, the long rod parts are placed vertically and positioned and straightened using a grid plate, which effectively limits the displacement of the parts during the heat treatment process. This placement method avoids the bending deformation caused by the tilting of one end of the parts in the traditional process, thereby significantly improving the dimensional accuracy and mechanical properties of the parts. The tooling design in this scheme allows the entire support part to be heat treated together with the tooling in a partition furnace, so that multiple parts can be processed at one time, reducing the time and labor required for processing a single part and improving production efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of heat treatment processing, and specifically to a method for reducing the heat treatment deformation of long rod parts. Background Art

[0002] In the fields of mechanical manufacturing and metal processing, the heat treatment of long rod parts is a key process, which directly affects the mechanical properties and dimensional accuracy of the parts. Traditional heat treatment processes, such as continuous mesh belt furnace heating, quenching, tempering, etc., usually have some problems that are difficult to overcome. Especially for long rod parts, due to their shape characteristics of being thick in the middle and thin at both ends, when placed horizontally on the mesh belt for heat treatment, one end and the middle of the part serve as support points, and the other end is prone to warping. This placement method is likely to cause the part to bend and deform during the heating, quenching, and tempering processes, seriously affecting the quality and performance of the part.

[0003] To solve this problem, the present invention provides a new heat treatment method. This process improvement effectively restricts the displacement of the part during the heat treatment process, thereby significantly reducing the bending deformation during the heat treatment process and improving the dimensional accuracy and mechanical properties of the part. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a method for reducing the heat treatment deformation of long rod parts, solving the problems proposed in the background art.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: A method for reducing the heat treatment deformation of long rod parts, the steps are as follows:

[0006] S01. Prepare the tooling: According to the size and shape of the long rod part, design and manufacture a special tooling, including a chassis, a pulling tool, a first tray, a second tray, a grid tray, a sleeve, and a vertical rod;

[0007] S02. Assemble the tooling: Insert the vertical rod into the corresponding hole positions of the chassis, and then place the first tray and the second tray on the vertical rod to ensure that the vertical rod can support the entire tooling structure;

[0008] S03. Position and straighten: Sleeve a sleeve outside the vertical rod so that the sleeve lands on the surfaces of the first tray and the second tray, and is used to support the grid tray above the first tray and the second tray;

[0009] S04. Place the part: Vertically stand the long rod part on the first tray and the second tray, ensure that the bottom of the long rod part is in stable contact with the first tray and the second tray, and use the grid tray to position and straighten the middle position of the long rod part to ensure that the long rod part remains vertical during the heating process and reduce the deformation caused by tilting;

[0010] S05. Fixing parts: Use a puller to connect and fix the vertical rods of two adjacent toolings, enabling the two toolings to be connected and fixed to each other, restricting the displacement of parts during the heat treatment process, so as to facilitate the batch heat treatment of long rod parts;

[0011] S06. Heat treatment: Put the whole tray of parts together with the tooling into a box furnace for heating, quenching and tempering; Since the long rod parts are restricted in displacement within the tooling, the bending deformation during the heat treatment process can be effectively reduced;

[0012] S07. Cooling and inspection: After the heat treatment is completed, let the parts cool naturally within the tooling or cool according to the process requirements; After cooling, check the dimensions and shapes of the long rod parts to ensure that the parts after heat treatment meet the quality requirements.

[0013] Preferably, the chassis includes a flat base for supporting the entire tooling structure, and the interior of the flat base is in a hollow structure. The chassis also includes a plurality of positioning holes evenly distributed on the flat base for receiving the insertion of the vertical rods to ensure the fixed position of the vertical rods on the chassis.

[0014] Preferably, both ends of the puller are provided with hole grooves, and the two hole grooves are sleeved outside the vertical rods of two adjacent toolings. The hole grooves at both ends of the puller are aligned with one end of the top of the sleeve, and a plurality of expansion joints are annularly and equidistantly distributed outside the vertical rods.

[0015] Preferably, the surfaces of the first tray and the second tray are in a hollow structure. A plurality of circular through holes are distributed on the surfaces of the first tray and the second tray, and the circular through holes are aligned with the circular through holes on the surface of the chassis. The vertical rods are inserted into the circular through holes on the surfaces of the first tray and the second tray for fixing the first tray and the second tray.

[0016] Preferably, the surface of the grid tray is in a hollow structure, and circular hole grooves are evenly distributed inside. The circular hole grooves on the surface of the grid tray are respectively used for fixing the vertical rods and the long rod parts. The bottom of the grid tray is supported by a sleeve, and the height of the sleeve is half of the length of the long rod part.

[0017] Preferably, in step S04, during the placement process of the long rod parts, ensure that the contact surfaces between the parts and the first tray and the second tray are clean and free of impurities to avoid uneven heat distribution caused by poor contact during the heat treatment process; At the same time, the contact points between the bottom of the long rod parts and the trays should be accurately positioned to ensure the vertical stability of the long rod parts during heating; In addition, the placement of the long rod parts should ensure that they are aligned with the hole grooves of the grid tray to achieve the positioning and straightening of the parts through the grid tray during the heat treatment process.

[0018] Preferably, in step S06, during the heat treatment process, the whole tray of long rod parts together with the tooling is placed in a box furnace, and the furnace atmosphere is controlled to be a protective gas environment to prevent the surface of the parts from oxidizing or decarburizing at high temperatures. At the same time, the temperature distribution in the furnace is uniform, ensuring that all long rod parts are heated uniformly during the heating process and reducing deformation caused by uneven temperature.

[0019] Preferably, in step S07, the natural cooling process is carried out under the condition that the ambient temperature is 20±5°C to ensure the stability of the cooling process. The tooling and long rod parts are placed in a well-ventilated environment, and the ventilation speed is controlled at 0.1 - 0.3 m / s to promote uniform cooling. The natural cooling time is 1 - 4 hours to avoid thermal shock and deformation caused by rapid cooling.

[0020] Preferably, in step S07, the inspection process includes measuring the outer diameter dimension of the long rod parts using precision measuring tools with a measurement accuracy of ±0.01 mm to ensure the dimensional accuracy after heat treatment. At the same time, the shape of the parts is visually inspected or detected using a profilometer device to ensure that the parts have no bending, twisting or other defects caused by heat treatment. The hardness test is carried out using a Vickers hardness tester with a test accuracy of ±1 HV to verify whether the heat treatment effect meets the expected mechanical properties.

[0021] The present invention provides a method for reducing the heat treatment deformation of long rod parts. It has the following beneficial effects:

[0022] (1) Reducing heat treatment deformation: By adopting the tooling of this solution, the long rod parts are placed vertically and positioned and straightened using a grid plate, effectively restricting the displacement of the parts during the heat treatment process. This placement method avoids the bending deformation caused by one end of the parts tilting up in the traditional process, thus significantly improving the dimensional accuracy and mechanical properties of the parts.

[0023] (2) Improving production efficiency: The tooling design in this solution allows the whole tray of parts together with the tooling to be heat-treated in a box furnace, so that multiple parts can be processed at one time, reducing the time and labor required for processing a single part and improving production efficiency.

[0024] (3) Optimizing heat treatment quality: Since the displacement of the parts is restricted in the tooling, the heat distribution during the heat treatment process is more uniform, reducing the thermal stress and deformation caused by local overheating or uneven cooling. In addition, the design of the tooling helps to control the cooling process, further ensuring the quality of the parts after heat treatment and making the mechanical properties of the parts more stable and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic flow chart of the present invention;

[0026] Figure 2 Schematic diagram of the tooling structure of the present invention;

[0027] Figure 3 Side view schematic diagram of the tooling structure of the present invention;

[0028] Figure 4 Schematic diagram of the long rod part structure;

[0029] Figure 5 Schematic diagram of the prior art.

[0030] In the figure, 1 is the chassis; 2 is the pulling tool; 3 is the vertical rod; 4 is the first tray; 5 is the second tray; 6 is the grid tray; 7 is the sleeve. Specific implementation method

[0031] Next, in combination with the drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Embodiment 1

[0032] Prepare the tooling and design a special tooling suitable for long rod parts with a diameter of 20 mm and a length of 500 mm, including the chassis 1, the pulling tool 2, the first tray 4, the second tray 5, the grid tray 6, the sleeve 7 and the vertical rod 3;

[0033] Assemble the tooling, accurately insert the vertical rod 3 into the positioning hole of the chassis 1 to ensure stability, and then place the first tray 4 and the second tray 5, and fix them through the through holes on the vertical rod 3;

[0034] Position and straighten. The sleeve 7 is sleeved outside the vertical rod 3 to ensure that the grid tray 6 can be stably placed above the first tray 4 and the second tray 5;

[0035] Place the parts. Vertically place the long rod parts on the first tray 4 and the second tray 5, and use the grid tray 6 to position and straighten in the middle position to ensure a vertical state;

[0036] Fix the parts. Use the pulling tool 2 to connect and fix the vertical rods 3 of two adjacent toolings to limit the displacement of the parts and facilitate batch heat treatment;

[0037] Heat treatment. Put the whole tray of parts together with the tooling into the box furnace, control the atmosphere in the furnace as an inert gas, with uniform temperature distribution, and perform heating, quenching and tempering;

[0038] Cooling and inspection. Naturally cool for 2 hours, control the ventilation speed at 0.2 m / s, use precision measuring tools to check that the dimensional accuracy reaches ±0.01 mm, and the hardness test accuracy is ±1 HV. Example 2

[0039] Prepare the tooling and design a special tooling suitable for long rod parts with a diameter of 25 mm and a length of 600 mm.

[0040] Assemble the tooling. Insert the vertical rod 3 into the hole position of the chassis 1, place the first tray 4 and the second tray 5, and ensure that the vertical rod 3 supports the entire tooling structure.

[0041] Position and straighten. The sleeve 7 is sleeved outside the vertical rod 3 to support the grid plate 6 and ensure the stability of the grid plate 6.

[0042] Place the parts. Place the long rod parts vertically and use the grid plate 6 for positioning to ensure they remain vertical during the heating process.

[0043] Fix the parts. The puller 2 is connected to adjacent vertical rods 3 to restrict the displacement of the parts and achieve batch heat treatment.

[0044] Heat treatment. Put it into a box furnace, control the furnace atmosphere as a protective gas, with uniform temperature, and conduct heat treatment.

[0045] Cooling and inspection. Naturally cool for 3 hours, with a ventilation speed of 0.25 m / s. Use a Vickers hardness tester for hardness testing to ensure the expected mechanical properties are achieved. Example 3

[0046] Prepare the tooling and design a special tooling suitable for long rod parts with a diameter of 30 mm and a length of 700 mm.

[0047] Assemble the tooling. Insert the vertical rod 3 into the hole position of the chassis 1, place the first tray 4 and the second tray 5, and ensure the stability of the vertical rod 3.

[0048] Position and straighten. The sleeve 7 is sleeved outside the vertical rod 3 to support the grid plate 6 and ensure the stability of the grid plate 6.

[0049] Place the parts. Place the long rod parts vertically and use the grid plate 6 for positioning to ensure they remain vertical during the heating process.

[0050] Fix the parts. The puller 2 is connected to adjacent vertical rods 3 to restrict the displacement of the parts and facilitate batch heat treatment.

[0051] Heat treatment. Put the whole tray of parts together with the tooling into a box furnace, control the furnace atmosphere as an inert gas, with uniform temperature distribution, and conduct heating, quenching, and tempering.

[0052] Cooling and inspection. Naturally cool for 4 hours, with a ventilation speed of 0.3 m / s. Use precision measuring tools and a profiler to check the dimensions and shape to ensure there are no defects.

[0053] Comparative Example 1:

[0054] Preparation stage: Select the traditional mesh belt continuous furnace as the heat treatment equipment (such as Figure 5 As shown in the figure), no special tooling is designed and mesh belt is used as support;

[0055] Parts placement: Place the long-rod parts horizontally on the mesh belt without taking any fixing measures, and the parts are placed freely on the mesh belt;

[0056] Heating process: During the heating process, due to the continuous movement of the mesh belt and the free placement of the parts, one end of the part naturally rises, resulting in uneven heating;

[0057] Heat treatment: During the quenching and tempering process, parts are bent and deformed due to warping, and due to the vibration of the mesh belt, parts may collide with each other, increasing the risk of deformation;

[0058] Cooling process: After the heat treatment is completed, the parts are cooled naturally on the mesh belt, and the ventilation speed is not controlled, resulting in inconsistent cooling speed;

[0059] Inspection stage: After cooling, the parts were inspected for size and shape, and it was found that due to uneven cooling and warping during heat treatment, the dimensional accuracy and shape of the parts did not meet the expected requirements.

[0060] Comparative Example 2:

[0061] Preparation stage: choose a traditional heat treatment furnace, use a common tray as support, and do not design special tooling;

[0062] Parts placement: Place the long-rod parts flat on a common tray without using the grid tray 6 and sleeve 7 for positioning and straightening;

[0063] Heating process: During the heating process, due to the flat support of the tray and the flat placement of the parts, the parts are prone to tilt at high temperatures, resulting in uneven heating;

[0064] Heat treatment: During the quenching and tempering process, the parts will bend due to tilting, and the thermal expansion of the parts at high temperatures may cause further tilting;

[0065] Cooling process: After the heat treatment is completed, rapid cooling is adopted, and the flow rate and temperature of the cooling medium are not accurately controlled, resulting in thermal shock and deformation;

[0066] Inspection stage: After cooling, the parts were inspected for surface quality and hardness, and oxide scale and decarburization were found on the surface of the parts. The hardness test showed that the expected mechanical properties were not achieved, which may be caused by rapid cooling and oxidation reaction at high temperature.

[0067] In order to verify the effectiveness of the method of the present invention, this program designed and conducted a series of heat treatment experiments, and compared the results with the prior art. The following is a detailed comparison table of experimental data;

[0068] Table 1: Comparison of dimensional accuracy:

[0069]

[0070] It can be seen from the data in Table 1 that Examples 1, 2, and 3 using the method of the present invention are significantly superior to Comparative Examples 1 and 2 of the traditional method in terms of dimensional accuracy.

[0071] The data comparison in Table 1 clearly demonstrates the significant advantages of the method of the present invention in controlling the dimensional accuracy of long rod parts. The dimensional deviations of Examples 1, 2, and 3 are all maintained within a strict range of ±0.01 mm, which is much lower than those of Comparative Examples 1 and 2 of the traditional heat treatment method, whose dimensional deviations reach ±0.0433 mm and ±0.06 mm respectively. This indicates that the tooling design and heat treatment process of the present invention can effectively reduce the dimensional changes during the heat treatment process and improve the dimensional accuracy of the parts.

[0072] Table 2: Comparison of hardness test results:

[0073]

[0074] Table 2 shows the influence of different heat treatment methods on the hardness of the parts. The hardness test results of the examples are more concentrated, with the hardness fluctuation range between 3 - 4 HV, and the average hardness value is close to the expected target.

[0075] In contrast, the hardness test results of Comparative Examples 1 and 2 show large fluctuations, and the hardness values deviate from the expected target, which may be due to inaccurate temperature control and inconsistent cooling rates in the traditional heat treatment method. This inconsistency in hardness may affect the performance of the parts and even lead to early failure.

[0076] Table 3: Comparison of surface quality and deformation

[0077]

[0078] It can be clearly seen from the data in Table 3 that the parts processed by the method of the present invention have significant advantages in terms of surface quality and deformation control. The parts in the examples have no oxide scale on the surface and no deformation occurs, while the parts in the comparative examples have oxide scale and serious deformation problems. This shows that the heat treatment process and tooling design of the present invention can effectively avoid surface damage and deformation during the heat treatment process, thereby improving the overall quality of the parts.

[0079] In summary, the heat treatment method provided by the present invention is superior to the prior art in terms of dimensional accuracy, hardness consistency, surface quality, and deformation control, and can significantly improve the heat treatment quality of long rod parts.

[0080] The foregoing has shown and described the basic principles, main features and advantages of the present invention. For a person skilled in the art, it is obvious that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and without departing from the spirit or basic features of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes that fall within the meaning and scope of the equivalent elements of the claims in the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

[0081] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for the sake of clarity. A person skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by a person skilled in the art.

Claims

1. A method for reducing the heat treatment deformation of long rod parts, characterized in that, The steps are as follows: S01. Prepare the tooling: According to the size and shape of the long rod parts, design and manufacture special tooling, including a chassis (1), a pulling tool (2), a first tray (4), a second tray (5), a grid tray (6), a sleeve (7) and a vertical rod (3); S02. Assemble the tooling: Insert the vertical rod (3) into the corresponding holes of the chassis (1), and then place the first tray (4) and the second tray (5) on the vertical rod (3) to ensure that the vertical rod (3) can support the entire tooling structure; S03. Position and straighten: Fit a sleeve (7) over the outside of the vertical rod (3) so that the sleeve (7) rests on the surfaces of the first tray (4) and the second tray (5) for supporting the grid tray (6) above the first tray (4) and the second tray (5); S04. Place the parts: Vertically stand the long rod parts on the first tray (4) and the second tray (5) to ensure that the bottom of the long rod parts is in stable contact with the first tray (4) and the second tray (5). Use the grid tray (6) to position and straighten the long rod parts at the middle position to ensure that the long rod parts remain vertical during the heating process and reduce deformation caused by tilting; S05. Fix the parts: Use the pulling tool (2) to connect and fix the vertical rods (3) of two adjacent toolings so that the two toolings can be connected and fixed to limit the displacement of the parts during the heat treatment process, facilitating the batch heat treatment of the long rod parts; S06. Heat treatment: Put the whole tray of parts together with the tooling into a box furnace for heating, quenching and tempering; Since the displacement of the long rod parts in the tooling is restricted, the bending deformation during the heat treatment process can be effectively reduced; S07. Cooling and inspection: After the heat treatment is completed, let the parts cool naturally in the tooling or cool according to the process requirements; After cooling, check the size and shape of the long rod parts to ensure that the parts after heat treatment meet the quality requirements; The chassis (1) includes a flat base for supporting the entire tooling structure, and the inside of the flat base is in a hollow structure. The chassis (1) also includes a plurality of positioning holes evenly distributed on the flat base for receiving the insertion of the vertical rod (3) to ensure the fixed position of the vertical rod (3) on the chassis (1); The surface of the grid tray (6) is in a hollow structure, and circular holes are evenly distributed inside. The circular holes on the surface of the grid tray (6) are respectively used to fix the vertical rod (3) and the long rod parts. The bottom of the grid tray (6) is supported by a sleeve (7), and the height of the sleeve (7) is half of the length of the long rod parts; In step S06, during the heat treatment process, the whole tray of long rod parts together with the tooling is put into a chamber furnace, and the atmosphere in the furnace is controlled to be a protective gas environment to prevent the surface of the parts from oxidizing or decarburizing at high temperatures; At the same time, the temperature distribution in the furnace is uniform to ensure that all long rod parts are heated uniformly during the heating process and reduce deformation caused by uneven temperature; In the step S07, the natural cooling process is carried out under the condition that the ambient temperature is 20±5°C to ensure the stability of the cooling process; the tooling and the long rod parts are placed in a well-ventilated environment, and the ventilation speed is controlled at 0.1-0.3 m / s to promote uniform cooling; the natural cooling time is 1-4 hours to avoid thermal shock and deformation caused by rapid cooling.

2. The method for reducing the heat treatment deformation of the long rod part according to claim 1, characterized in that: Holes and grooves are provided at both ends of the pulling tool (2), and the two holes and grooves are sleeved outside the vertical rods (3) of two adjacent toolings. One end of the top of the sleeve (7) is aligned with the holes and grooves at both ends of the pulling tool (2). A plurality of expansion joints are distributed in an annular and equidistant manner on the outside of the vertical rod (3).

3. A method for reducing the heat treatment deformation of a long rod part according to claim 1, characterized in that: The surfaces of the first tray (4) and the second tray (5) are of a hollow structure. A plurality of circular through holes are distributed on the surfaces of the first tray (4) and the second tray (5), and the circular through holes are aligned with the circular through holes on the surface of the chassis (1). The vertical rods (3) are inserted into the circular through holes on the surfaces of the first tray (4) and the second tray (5) for fixing the first tray (4) and the second tray (5).

4. A method for reducing the heat treatment deformation of a long rod part according to claim 1, characterized in that: In the step S04, during the placement of the long rod parts, it is ensured that the contact surfaces between the parts and the first tray (4) and the second tray (5) are clean and free of impurities to avoid uneven heat distribution caused by poor contact during the heat treatment process; at the same time, the contact points between the bottom of the long rod parts and the trays should be accurately positioned to ensure the vertical stability of the long rod parts during the heating process; in addition, the placement of the long rod parts should ensure that they are aligned with the holes and grooves of the grid plate (6) so as to realize the positioning and straightening of the parts through the grid plate (6) during the heat treatment process.

5. A method for reducing the heat treatment deformation of long rod parts according to claim 1, characterized in that: In the step S07, the inspection process includes measuring the outer diameter dimension of the long rod part using a precision measuring tool with a measurement accuracy of ±0.01 mm to ensure its dimensional accuracy after heat treatment. At the same time, the shape of the part is visually inspected or detected using a profiler device to ensure that the part has no bending, twisting or other defects caused by heat treatment. The hardness test is carried out using a Vickers hardness tester with a test accuracy of ±1 HV to verify whether the heat treatment effect meets the expected mechanical properties.

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