Method for reducing heat treatment deformation of long rod part

Abstract

The invention discloses a method for reducing heat treatment deformation of a long rod part, and relates to the technical field of heat treatment processing.The method comprises the following steps of S01, tool preparing, S02, tool assembling, S03, positioning and righting, S04, part placing, S05, part fixing, S06, heat treatment and S07, cooling and checking.By adopting the tool, the long rod part is vertically placed in a standing mode, a lattice disc is used for positioning and righting, and the long rod part is prevented from being deformed; according to the heat treatment tool for the parts, the displacement of the parts in the heat treatment process is effectively limited, bending deformation caused by tilting of one ends of the parts in a traditional technology is avoided through the placing mode, and therefore the size precision and mechanical performance of the parts are remarkably improved. The tool design in the scheme allows the whole support parts and the tool to be subjected to heat treatment together in a partition type furnace, and the heat treatment efficiency is improved. In this way, a plurality of parts can be processed at a time, time and labor needed for processing a single part are reduced, and production efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of heat treatment processing, in particular to a method for reducing heat treatment deformation of a long rod part. Background Art

[0002] In the field of mechanical manufacturing and metal processing, 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 mesh belt continuous furnace heating, quenching, tempering, etc., usually have some difficult to overcome problems. Especially for long rod parts, due to their appearance 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 easily causes the parts to bend and deform during the heating, quenching, and tempering process, which seriously affects the quality and performance of the parts.

[0003] In order to solve this problem, the present invention provides a new heat treatment method. This process improvement effectively limits the displacement of parts 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 parts. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a method for reducing the heat treatment deformation of a long rod part, thereby solving the problems raised in the background art.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for reducing the heat treatment deformation of a long rod part, the steps of which are as follows: S01. Prepare tooling: Design and manufacture special tooling according to the size and shape of the long rod parts, including chassis, puller, first material tray, second material tray, grid tray, sleeve and vertical rod; S02. Assemble the tooling: insert the vertical rod into the corresponding hole of the chassis, and then place the first material tray and the second material tray on the vertical rod to ensure that the vertical rod can support the entire tooling structure; S03 positioning and straightening: the outer sleeve of the pole is set so that the sleeve falls on the surface of the first tray and the second tray, and is used to support the grid plate above the first tray and the second tray; S04. Parts placement: Place the long-rod parts upright on the first and second trays, ensuring that the bottom of the long-rod parts are in stable contact with the first and second trays. Use a grid plate to position and straighten the long-rod parts in the middle to ensure that the long-rod parts remain vertical during heating to reduce deformation caused by tilting. S05. Fixing parts: Use a puller to connect and fix the vertical rods of two adjacent toolings so that the two toolings can be connected and fixed to each other, limiting the displacement of the parts during the heat treatment process, so as to facilitate the batch heat treatment of long rod parts; S06. Heat treatment: Put the whole tray parts together with the tooling into the partition furnace for heating, quenching and tempering; because the long rod parts are restricted in displacement in the tooling, 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.

[0006] Preferably, the chassis includes a planar base for supporting the entire tooling structure, and the interior of the planar base is a hollow structure. The chassis also includes a plurality of positioning holes evenly distributed on the planar base for receiving the insertion of the vertical poles to ensure the fixed position of the vertical poles on the chassis.

[0007] Preferably, holes are provided at both ends of the puller, and the two holes are sleeved on the outside of the vertical poles of two adjacent toolings, the holes at both ends of the puller are aligned with one end of the top of the sleeve, and multiple expansion joints are distributed in a circular shape with equal spacing on the outside of the vertical pole.

[0008] Preferably, the surfaces of the first material tray and the second material tray are hollow structures, and a plurality of circular through holes are distributed on the surfaces of the first material tray and the second material tray, and the circular through holes are aligned with the circular through holes on the surface of the chassis, and vertical rods are inserted into the circular through holes on the surfaces of the first material tray and the second material tray for fixing the first material tray and the second material tray.

[0009] Preferably, the grid plate surface is a hollow structure with circular holes evenly distributed inside, the circular holes on the grid plate surface are used to fix the vertical poles and the long rod parts respectively, and the bottom of the grid plate is supported by a sleeve, wherein the height of the sleeve is half the length of the long rod part.

[0010] Preferably, in step S04, during the placement of the long rod parts, ensure that the contact surfaces between the parts and the first material tray and the second material tray are clean and free of impurities to avoid uneven heat distribution due to poor contact during the heat treatment process; at the same time, the contact point between the bottom of the long rod parts and the material tray should be precisely 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 slots of the grid tray so that the parts can be positioned and straightened by the grid tray during the heat treatment process.

[0011] Preferably, in step S06, during the heat treatment process, the entire support of the long rod parts together with the tooling are placed in a partition furnace, and the atmosphere in the furnace is controlled to be an inert or protective gas environment to prevent the surface of the parts from oxidation or decarburization at high temperatures; at the same time, the temperature in the furnace is evenly distributed to ensure that all long rod parts are heated uniformly during the heating process, reducing deformation caused by uneven temperature.

[0012] Preferably, in step S07, the natural cooling process is carried out under an ambient temperature of 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.

[0013] Preferably, in step S07, the inspection process includes using a precision measuring tool to measure the outer diameter of the long rod part 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 tested using a profilometer device to ensure that the part has no bending, twisting or other defects caused by heat treatment. The hardness test is performed using a Vickers hardness tester with a test accuracy of ±1HV to verify whether the heat treatment effect achieves the expected mechanical properties.

[0014] The present invention provides a method for reducing the heat treatment deformation of long rod parts. It has the following beneficial effects: (1) Reducing deformation during heat treatment: By adopting the tooling of this solution, 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 part in the traditional process, thereby significantly improving the dimensional accuracy and mechanical properties of the parts.

[0015] (2) Improve production efficiency: The tooling design in this solution allows the entire tray of parts to be heat treated together with the tooling in a partition furnace. This allows multiple parts to be processed at one time, reducing the time and labor required for processing a single part and improving production efficiency.

[0016] (3) Optimizing heat treatment quality: Since the displacement of parts is restricted in the tooling, the heat distribution during the heat treatment process is more uniform, reducing thermal stress and deformation caused by local overheating or uneven cooling. In addition, the design of the tooling helps control the cooling process, further ensuring the quality of parts after heat treatment, making the mechanical properties of the parts more stable and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the process of the present invention; Figure 2 It is a schematic diagram of the tooling structure of the present invention; Figure 3 It is a schematic diagram of the side view structure of the tooling of the present invention; Figure 4 It is a schematic diagram of the structure of the long rod parts; Figure 5 It is a schematic diagram of the prior art.

[0018] In the figure, 1, chassis; 2, puller; 3, vertical pole; 4, first material tray; 5, second material tray; 6, grid tray; 7, sleeve. DETAILED DESCRIPTION

[0019] The following will be combined with the 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 without creative work are within the scope of protection of the present invention. Example 1

[0020] Prepare tooling and design a special tooling suitable for long rod parts with a diameter of 20 mm and a length of 500 mm, including a chassis 1, a puller 2, a first material tray 4, a second material tray 5, a grid tray 6, a sleeve 7 and a vertical rod 3; Assemble the tooling, accurately insert the vertical rod 3 into the positioning hole of the chassis 1 to ensure stability, then place the first material tray 4 and the second material tray 5 and fix them through the through holes on the vertical rod 3; Positioning and straightening, the sleeve 7 is sleeved on the outside of the vertical rod 3 to ensure that the grid tray 6 can be stably placed above the first material tray 4 and the second material tray 5; For parts placement, place the long-rod parts vertically on the first tray 4 and the second tray 5, and use the grid tray 6 to position and straighten them in the middle to ensure a vertical state; Fix the parts, use the puller 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; Heat treatment: put the whole tray parts together with the tooling into a partition furnace, control the atmosphere in the furnace to be inert gas, and evenly distribute the temperature to perform heating, quenching and tempering; Cooling and inspection: natural cooling for 2 hours, ventilation speed controlled at 0.2 m / s, use precision measuring tools to check that the dimensional accuracy reaches ±0.01mm, and the hardness test accuracy is ±1HV. Example 2

[0021] Prepare tooling and design special tooling for long rod parts with a diameter of 25 mm and a length of 600 mm; Assemble the tooling, insert the vertical rod 3 into the hole of the chassis 1, place the first material tray 4 and the second material tray 5, and ensure that the vertical rod 3 supports the entire tooling structure; Positioning and straightening, the sleeve 7 is sleeved on the outside of the vertical pole 3 to support the grid plate 6 to ensure the stability of the grid plate 6; When placing parts, long-rod parts should be placed vertically and positioned using the grid plate 6 to ensure that they remain vertical during heating; Fix the parts, the puller 2 connects the adjacent vertical rods 3, limits the displacement of the parts, and realizes batch heat treatment; Heat treatment: put it into a partition furnace, control the atmosphere in the furnace to be protective gas, and carry out heat treatment at a uniform temperature; Cooling and inspection: natural cooling for 3 hours, ventilation speed 0.25 m / s, hardness test using Vickers hardness tester to ensure that the expected mechanical properties are achieved. Example 3

[0022] Prepare tooling and design special tooling for long rod parts with a diameter of 30 mm and a length of 700 mm; Assemble the tooling, insert the vertical pole 3 into the hole of the chassis 1, place the first material tray 4 and the second material tray 5, and ensure the stability of the vertical pole 3; Positioning and straightening, the sleeve 7 is sleeved on the outside of the vertical pole 3 to support the grid plate 6 to ensure the stability of the grid plate 6; When placing parts, long-rod parts should be placed vertically and positioned using the grid plate 6 to ensure that they remain vertical during heating; To fix the parts, the puller 2 connects the adjacent vertical rods 3 to limit the displacement of the parts and facilitate batch heat treatment; Heat treatment: put the whole tray parts together with the tooling into a partition furnace, control the atmosphere in the furnace to be inert gas, and evenly distribute the temperature to perform heating, quenching and tempering; Cooling and inspection: natural cooling for 4 hours, ventilation speed 0.3 m / s, use precision measuring tools and profilometers to check size and shape to ensure there are no defects.

[0023] Comparative Example 1: 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; 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; 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; 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; 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; 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.

[0024] Comparative Example 2: Preparation stage: choose a traditional heat treatment furnace, use a common tray as support, and do not design special tooling; 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; 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; 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; 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; 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.

[0025] 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; Table 1: Dimensional accuracy comparison: Experiment number Part diameter (mm) Part length (mm) Measured size deviation (mm) Average size deviation (mm) Example 1 20 500 ±0.005,±0.008,±0.012 ±0.0083 Example 2 25 600 ±0.004,±0.006,±0.010 ±0.0057 Example 3 30 700 ±0.003,±0.007,±0.009 ±0.0057 Comparative Example 1 20 500 ±0.03,±0.04,±0.06 ±0.0433 Comparative Example 2 25 600 ±0.05,±0.06,±0.07 ±0.06 It can be seen from the data in Table 1 that the dimensional accuracy of Examples 1, 2 and 3 using the method of the present invention is significantly better than that of Comparative Examples 1 and 2 using the traditional method.

[0026] 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 kept within a strict range of ±0.01 mm, which is much lower than that 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 shows 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. Table 2: Comparison of hardness test results: Experiment number Part diameter (mm) Part length (mm) Hardness test value (HV) Average hardness (HV) Hardness fluctuation range (HV) Example 1 20 500 500,502,498 500.33 4 Example 2 25 600 550,552,549 550.67 3 Example 3 30 700 600,602,598 600.33 4 Comparative Example 1 20 500 450,460,470 460 20 Comparative Example 2 25 600 520,530,540 530 20 Table 2 shows the effect of different heat treatment methods on the hardness of the parts. The hardness test results of the embodiment are more concentrated, the hardness fluctuation range is between 3-4HV, and the average hardness value is close to the expected target.

[0027] 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 caused by the inaccurate temperature control and inconsistent cooling rate in the traditional heat treatment method. This inconsistency in hardness may affect the performance of the parts and even lead to early failure.

[0028] Table 3: Comparison of surface quality and deformation Experiment number Part diameter (mm) Part length (mm) Surface quality Deformation Example 1 20 500 No oxide scale No deformation Example 2 25 600 No oxide scale No deformation Example 3 30 700 No oxide scale No deformation Comparative Example 1 20 500 With oxide skin Severe deformation Comparative Example 2 25 600 With oxide skin Severe deformation It can be clearly seen from the data in Table 3 that the parts treated by the method of the present invention have significant advantages in terms of surface quality and deformation control. The parts in the embodiment have no oxide scale on the surface and no deformation, while the parts in the comparative example 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.

[0029] In summary, the heat treatment method provided by the present invention is superior to the existing technology in terms of dimensional accuracy, hardness consistency, surface quality and deformation control, and can significantly improve the heat treatment quality of long rod parts.

[0030] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0031] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for reducing heat treatment deformation of long rod parts, characterized in that: The steps are as follows: S01. Prepare tooling: Design and manufacture special tooling according to the size and shape of the long rod part, including a chassis (1), a puller (2), a first material tray (4), a second material tray (5), a grid tray (6), a sleeve (7) and a vertical rod (3); S02. Assembling the tooling: inserting the vertical rod (3) into the corresponding hole of the chassis (1), and then placing the first material tray (4) and the second material tray (5) on the vertical rod (3), ensuring that the vertical rod (3) can support the entire tooling structure; S03 positioning and straightening: the outer sleeve (7) of the upright (3) is set so that the sleeve (7) falls on the surface of the first tray (4) and the second tray (5) to support the grid plate (6) above the first tray (4) and the second tray (5); S04. Parts placement: Place the long-rod parts upright on the first material tray (4) and the second material tray (5), ensuring that the bottom of the long-rod parts are in stable contact with the first material tray (4) and the second material tray (5), and use a grid plate (6) to position and straighten the middle of the long-rod parts to ensure that the long-rod parts remain in a vertical state during the heating process to reduce deformation caused by tilting; S05. Fixing the parts: Use a puller (2) to connect and fix the vertical rods (3) of two adjacent toolings so that the two toolings can be connected and fixed to each other, limiting the displacement of the parts during the heat treatment process, so as to facilitate batch heat treatment of long rod parts; S06. Heat treatment: Put the whole tray parts together with the tooling into the partition furnace for heating, quenching and tempering; because the long rod parts are restricted in displacement in the tooling, 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.

2. A method for reducing heat treatment deformation of a long rod part according to claim 1, characterized in that: The chassis (1) comprises a plane base for supporting the entire tooling structure, and the interior of the plane base is a hollow structure. The chassis (1) also comprises a plurality of positioning holes evenly distributed on the plane base for receiving the insertion of the vertical pole (3) to ensure that the vertical pole (3) is fixed in position on the chassis (1).

3. A method for reducing heat treatment deformation of long rod parts according to claim 1, characterized in that: The puller (2) is provided with holes and slots at both ends, and the two holes and slots are sleeved on the outside of two adjacent tooling uprights (3), the holes and slots at both ends of the puller (2) are aligned with one end of the top of the sleeve (7), and the outside of the upright (3) is provided with a plurality of expansion joints distributed in an annular shape at equal intervals.

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

5. A method for reducing heat treatment deformation of long rod parts according to claim 1, characterized in that: The surface of the grid plate (6) is a hollow structure, and circular holes and grooves are evenly distributed inside. The circular holes and grooves on the surface of the grid plate (6) are used to fix the vertical pole (3) and the long rod part respectively. The bottom of the grid plate (6) is supported by a sleeve (7), wherein the height of the sleeve (7) is half the length of the long rod part.

6. A method for reducing 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 material tray (4) and the second material tray (5) are clean and free of impurities, so as to avoid uneven heat distribution due to poor contact during the heat treatment process; at the same time, the contact point between the bottom of the long rod parts and the material 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 tray (6), so that the grid tray (6) can be used to position and straighten the parts during the heat treatment process.

7. A method for reducing heat treatment deformation of a long rod part according to claim 1, characterized in that: In step S06, during the heat treatment process, the entire support of the long rod parts together with the tooling are placed in a partition furnace, and the atmosphere in the furnace is controlled to be an inert or protective gas environment to prevent the surface of the parts from oxidation or decarburization at high temperatures; at the same time, the temperature in the furnace is evenly distributed to ensure that all long rod parts are heated uniformly during the heating process, reducing deformation caused by uneven temperature.

8. A method for reducing heat treatment deformation of a long rod part according to claim 1, characterized in that: In step S07, the natural cooling process is carried out under the condition of an ambient temperature of 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.

9. A method for reducing heat treatment deformation of a long rod part according to claim 1, characterized in that: In step S07, the inspection process includes using a precision measuring tool to measure the outer diameter of the long rod part 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 tested using a profilometer to ensure that the part has no bending, twisting or other defects caused by heat treatment. The hardness test is performed using a Vickers hardness tester with a test accuracy of ±1HV to verify whether the heat treatment effect achieves the expected mechanical properties.

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