Quenching process and device

Abstract

The invention relates to a quenching process and device, and relates to the field of metal heat treatment, the quenching process sequentially comprises a heating step, a quenching step, a tempering step and a quenching step, and the quenching step sequentially comprises a pre-cooling step, an intercooling step and a deep cooling step. According to the method, the workpiece is subjected to subzero treatment in stages after being subjected to conventional heat treatment, unstable retained austenite in the workpiece can be forcibly converted into martensite, and the hardness of the workpiece is improved; and meanwhile, the tempering step is adjusted, and the quenching step is carried out in stages, so that the concentration of thermal stress in the workpiece can be effectively reduced, and the probability of deformation and cracking of the workpiece is reduced.

Description

Technical Field

[0001] The present invention relates to the field of metal heat treatment processes, and in particular, to a quenching process and device. Background Art

[0002] During the metal processing, heat-treating the processed workpiece can change the mechanical properties of the workpiece, increase the toughness or hardness of the workpiece, and enable the processed workpiece to adapt to different working scenarios. Especially when processing rolls, in order to increase the hardness of the rolls, after processing the rolls, the workpiece needs to be quenched and tempered to convert high-carbon steel into high-hardness martensite.

[0003] Currently, a Chinese patent application with the publication number CN 116103482 A and the publication date of May 12, 2023, proposes a quenching and cold treatment process for high-carbon steel rolls, which includes the following steps: S1: Preheat the high-carbon steel roll workpiece in a quenching furnace in two stages; S2: Place the preheated high-carbon steel roll workpiece into a high-temperature melting furnace; S3: Combine air cooling and water cooling; S4: Place the cooled high-carbon steel roll workpiece into a tempering furnace for tempering treatment; S5: Place dry ice and the high-carbon steel roll workpiece in an adiabatic barrel at the same time, and let the dry ice absorb the heat of the workpiece during the gasification process to achieve the purpose of cold treatment.

[0004] During use, stepwise preheating is adopted during the preheating process to make the workpiece heat more evenly, and cold treatment is carried out after the workpiece is quenched to increase the hardness of the workpiece.

[0005] In view of the above-related technologies, the method of combining air cooling and water cooling is used for quenching and cooling, and the temperature change gradient is large, resulting in easy cracking due to the concentration of internal thermal stress in the workpiece. Moreover, the austenite conversion efficiency of the final low-temperature tempering and cold treatment processes is low, affecting the overall hardness of the workpiece. Summary of the Invention

[0006] In order to improve the overall hardness of the workpiece and reduce the cracking efficiency of the workpiece in the cold treatment step, the present invention provides a quenching process and device.

[0007] First aspect: The present invention provides a quenching process, adopting the following technical solutions: A quenching process, which successively includes a heating-up step, a quenching step, a tempering step, and a cryogenic cooling step: Heating-up step: The workpiece is heated up and held at a constant temperature in stages, and finally the workpiece is heated above Ac3 and held at a constant temperature to obtain austenite; Quenching step: The workpiece is quickly cooled below Ms, so that austenite is transformed into martensite; Tempering step: The workpiece is reheated to 200 °C to 400 °C and held for more than 4 hours to eliminate the internal stress of the workpiece; The rapid cooling step successively includes a pre-cooling step, a medium-cooling step, and a cryogenic cooling step: Pre-cooling step: The workpiece is cooled to -50 °C and held for 5 hours; Medium-cooling step: The workpiece is cooled to -100 °C and held for 5 hours; Cryogenic cooling step: The workpiece is cooled to -150 °C and held for 6 hours.

[0008] By adopting the above technical solution, when heating up the workpiece, heating up in stages can timely disperse the thermal stress inside the workpiece, reduce the concentration of thermal stress, and raise the temperature of the workpiece above Ac3 in the final heating-up stage to transform the metal phase of the workpiece into austenite. In the quenching step, quickly cooling the workpiece below the Ms point can convert austenite into martensite and increase the hardness of the workpiece. The tempering step can relieve the thermal stress accumulated inside the workpiece during the quenching step. In this application, the medium-temperature tempering is adopted in the tempering step and the holding time is longer, so that the thermal stress inside the workpiece is eliminated more thoroughly, preparing for the subsequent rapid cooling step in advance. In the rapid cooling step, the workpiece is cooled in three stages, mainly to forcibly transform the retained austenite that has not been completely transformed into martensite during the quenching step into martensite, so that the content of martensite in the final workpiece is higher, and thus the overall hardness of the workpiece can be increased. Dividing the rapid cooling step into three stages is to reduce the concentration of thermal stress inside the workpiece. Especially when processing special-shaped rollers, directly reducing the temperature to -150 °C will cause the rapid concentration of thermal stress at the corners of the roller body, and there is a risk of workpiece cracking. Cooling and holding in stages can gradually disperse the thermal stress inside the workpiece and reduce the risk of workpiece cracking.

[0009] Optionally, the heating-up step successively includes five stages: First stage: The workpiece is heated to 200 °C and held for a time of T1; Second stage: The workpiece is heated to 400 °C and held for a time of T2; Third stage: The workpiece is heated to 500 °C and held for a time of T3; Fourth stage: The workpiece is heated to 600 °C and held for a time of T4; Fifth stage: The workpiece is heated above 900 °C and held for a time of T5; and 1 hour < T1 < T2 < T3 < T4 < T5 < 2 hours.

[0010] By adopting the above technical solution, since high-carbon steel has poor thermal conductivity, the workpiece heating stage is refined into 200 °C, 400 °C, 500 °C, 600 °C and 900 °C, and heat preservation is carried out respectively, which can make the heat transfer more uniform, reduce the temperature difference between the core temperature and the surface temperature of the workpiece, thereby reducing the thermal stress inside the workpiece and the probability of cracking and deformation of the workpiece during quenching. And the heat preservation duration of the workpiece at different temperature stages increases with the increase of temperature because carbon will precipitate when the temperature of high-carbon steel rises, and the decrease of carbon content will lead to the decrease of the thermal conductivity coefficient of high-carbon steel, and then the thermal conductivity of high-carbon steel decreases with the increase of temperature. Therefore, increasing the heat preservation duration of the workpiece at different temperature stages with the increase of temperature can make the core temperature and the surface temperature of the workpiece consistent and reduce the thermal stress inside the workpiece.

[0011] Optionally, both the heating step and the quenching step are carried out in a vacuum environment.

[0012] By adopting the above technical solution, heating and quenching the workpiece in a vacuum environment can isolate the workpiece from oxygen, reduce the probability of the workpiece reacting with oxygen and carbon dioxide in the air at high temperature, and then reduce the oxide layer on the workpiece surface, improving the cleanliness and precision of the workpiece surface.

[0013] Optionally, the quenching step uses special quenching oil for quenching or uses inert gas for quenching.

[0014] By adopting the above technical solution, the special quenching oil has a specific cooling curve. Using the quenching oil to quench the workpiece can reduce the cooling speed of the workpiece and the risk of workpiece cracking. When using inert gas quenching, the quenching temperature can be adjusted to control the cooling speed of the workpiece and reduce the risk of workpiece cracking; and both oil quenching and inert gas quenching can isolate the workpiece from the air, reducing the probability of oxide scale formation on the workpiece surface and improving the cleanliness and precision of the workpiece.

[0015] Second aspect: The present invention provides a quenching device, adopting the following technical solution: A quenching device, comprising a furnace body, a heating chamber arranged inside the furnace body, and a quenching chamber arranged inside the furnace body. An air quenching chamber and an oil quenching chamber are arranged inside the quenching chamber. The air quenching chamber is arranged above the oil quenching chamber. A first sealing assembly and a second sealing assembly are arranged between the air quenching chamber and the oil quenching chamber. A guide rail is further arranged inside the air quenching chamber. The guide rail is slidably installed in the air quenching chamber in the vertical direction. When the air quenching chamber works, the second sealing assembly is closed, the air quenching chamber and the oil quenching chamber are isolated and sealed, the guide rail is located above the second sealing assembly, and the workpiece is supported on the guide rail. When the oil quenching chamber works, the workpiece descends into the oil quenching chamber along with the guide rail. The first sealing assembly is located above the guide rail, and the first sealing assembly is closed, so that the air quenching chamber and the oil quenching chamber are isolated and sealed.

[0016] When heat-treating a workpiece, after the workpiece is heated in a vacuum heating furnace and then directly placed in quenching oil for cooling, since the workpiece has a high temperature after heating, the direct contact between the high-temperature workpiece and the quenching oil will cause the quenching oil to evaporate, generating oil vapor that will pollute the inside of the quenching chamber. Moreover, when performing air quenching, if the oil mist of the quenching oil drifts into the air quenching chamber and contacts the gas used for quenching in the air quenching chamber and cools down along with the workpiece, it will cause an oil film or abnormal structure to remain on the surface of the workpiece, affecting the surface finish of the workpiece.

[0017] And the workpiece needs to move up and down in the quenching chamber so as to perform air quenching in the air quenching chamber or oil quenching in the oil quenching chamber. If only one set of sealing assemblies is arranged in the quenching chamber, the device for driving the workpiece to move up and down will be affected by the sealing assemblies when driving the workpiece to move up and down. Therefore, in this application, two sets of upper and lower sealing assemblies are arranged, and the device for driving the workpiece to move up and down is arranged between the two sets of upper and lower sealing assemblies. When the workpiece moves upward, the lower sealing assembly is closed. When the workpiece moves downward, the upper sealing assembly is closed, so that there is always one set of sealing assemblies in a sealed state during the up and down movement of the workpiece, and the air quenching chamber and the oil quenching chamber in the quenching chamber can be better isolated.

[0018] By adopting the above technical solution, when gas quenching the workpiece, the workpiece is placed on the guide rail in the gas quenching chamber. The second sealing component below the guide rail is closed, and the oil mist is isolated in the oil quenching chamber below the second sealing component, which can reduce the probability of the oil mist entering the gas quenching chamber and contacting the workpiece during the gas quenching process. At the same time, when oil quenching the workpiece, the workpiece is placed on the guide rail, and the workpiece descends along the guide rail into the oil quenching chamber below for oil quenching. At this time, the first sealing component above the guide rail is closed to isolate the oil quenching chamber from the gas quenching chamber, thereby reducing the probability of the oil mist generated at high temperature during the oil quenching of the workpiece entering the gas quenching chamber and polluting the gas quenching chamber. In this way, the first sealing component and the second sealing component can isolate the gas quenching chamber from the oil quenching chamber respectively during oil quenching and gas quenching, reduce the probability of the oil mist in the oil quenching chamber diffusing into the gas quenching chamber, and improve the cleanliness inside the workpiece and the gas quenching chamber.

[0019] Optionally, there are two sets of the first sealing components, and the two sets of the sealing components are respectively arranged opposite to each other on both sides of the guide rail. The first sealing component includes a first support member, a first driving member and a first sealing member. The first support member is fixedly arranged on the inner wall of the gas quenching chamber. The first support member is arranged along the length direction of the guide rail. The first sealing member is slidably arranged on the first support member. The first driving member is fixedly arranged on the first support member. The first driving member is used to drive the first sealing member to move along the direction of the first support member. There are two sets of the second sealing components, and the two sets of the second sealing components are respectively arranged on both sides of the guide rail. The second sealing component includes a second support member, a second driving member and a second sealing member. The second support member is fixedly arranged on the inner wall of the oil quenching chamber. The second support member is arranged along the length direction of the guide rail. The second sealing member is fixedly arranged on the second support member. The second driving member is fixedly arranged on the second support member. The second driving member is used to drive the second sealing member to move along the direction of the second support member. The guide rail is installed on the first sealing member through a connecting rod assembly, and the connecting rod assembly is used to control the up and down movement of the guide rail.

[0020] By adopting the above technical solution, when the gas quenching chamber is working, the workpiece is supported in the gas quenching chamber along with the guide rail. The second sealing assembly is located below the guide rail, and the second driving members in the two groups of second sealing assemblies respectively arranged below the guide rail drive the second sealing members to slide along the direction of the second supporting member, so that the ends of the two second sealing members arranged oppositely on both sides of the guide rail abut against each other, and sealing isolation is carried out below the guide rail; when the oil quenching chamber is working, the workpiece moves downward along with the guide rail into the oil quenching chamber. At this time, the second sealing assembly is opened, the first sealing assembly is located above the guide rail, and the first driving members in the two groups of first sealing assemblies respectively arranged above the guide rail drive the first sealing members to slide along the direction of the first supporting member, so that the ends of the two second sealing members arranged oppositely on both sides of the guide rail abut against each other, and sealing isolation is carried out above the guide rail; and the guide rail is installed on the first sealing member through the connecting rod assembly, so that the up and down movement of the guide rail moves along with the opening and closing of the first sealing assembly, eliminating the driving structure for the up and down movement of the guide rail, and enabling the linkage between the first sealing assembly and the guide rail, realizing the synchronous movement between the first sealing assembly and the guide rail. In this way, when the gas quenching chamber and the oil quenching chamber are working, the first sealing assembly and the second sealing assembly are respectively closed, which can isolate the gas quenching chamber from the oil quenching chamber, reducing the pollution caused by the diffusion of oil mist into the gas quenching chamber; and the setting of the connecting rod assembly plays a linkage role in the movement between the first sealing assembly and the guide rail, enabling the synchronous movement between the first sealing assembly and the guide rail.

[0021] Optionally, the connecting rod assembly includes a first rotating shaft, a second rotating shaft and a connecting rod. The first rotating shaft is fixedly arranged on the first supporting member, the second rotating shaft is fixedly arranged on the guide rail, one end of the connecting rod is rotatably connected to the first rotating shaft, and the other end of the connecting rod is rotatably connected to the second rotating shaft.

[0022] By adopting the above technical solution, when the first sealing member moves, the connecting rod rotates with the first rotating shaft and the second rotating shaft as the first sealing member moves. The two first sealing members on both sides of the guide rail move towards each other, and the guide rail moves downward under the action of gravity, so that the guide rail continuously moves downward; the two first sealing members on both sides of the guide rail move away from each other, and the guide rail moves upward under the pulling force of the connecting rod. In this way, the linkage between the guide rail and the first sealing member can be realized through a simple connecting rod assembly, which not only eliminates the driving structure of the guide rail, but also enables the synchronous movement of the first sealing member and the guide rail.

[0023] Optionally, a guide rail is arranged above the first sealing member. When the gas quenching chamber is working, the first sealing assembly is opened, and the guide rail is flush with the guide rail on the first sealing member; a support assembly is arranged above the second sealing member. When the second sealing assembly is closed, the support assembly is used for supporting below the guide rail, and at this time, the end of the connecting rod connected to the first rotating shaft is lower than the other end.

[0024] Since only the driving force and the supporting force are provided by pulling through the connecting rod during the movement of the guide rail, when the connecting rod tends to be horizontal, the supporting force provided by the connecting rod for the guide rail in the vertical direction will gradually decrease, resulting in unstable support; by adopting the above technical solution, when the gas quenching chamber works, the first sealing assembly is opened and the second sealing assembly is closed. When the guide rail is supported in the gas quenching chamber, the upper end of the guide rail is flush with the first seal, and the lower part of the guide rail is supported by the supporting assembly arranged on the first seal, so that the bottom of the guide rail can be supported by the supporting assembly and limited by the abutting part, increasing the stability of the guide rail supported in the gas quenching chamber. At the same time, the end of the connecting rod connected to the guide rail is set lower than the end connected to the first seal, which can increase the supporting force provided by the connecting rod for the guide rail in the vertical direction and further improve the stability of the guide rail.

[0025] Optionally, the supporting assembly includes a first abutting block, a second abutting block and an abutting rod. The first abutting block is fixedly arranged on the second seal. One end of the abutting rod is rotatably connected to the first abutting block, and the second abutting block is rotatably installed at the other end of the abutting rod; a convex platform is arranged at the bottom of the guide rail. When the second sealing assembly is closed, the second abutting block abuts at the included angle between the convex platform and the bottom surface of the guide rail to support the guide rail.

[0026] By adopting the above technical solution, the first abutting block is fixedly arranged on the second seal and moves with the second seal. When the second seal is closed, the first abutting blocks on the two second seals located on both sides of the guide rail move towards each other with the second seal. The first abutting block will drive the abutting rod and the second abutting block to move synchronously, so that the second abutting block abuts on the convex platform at the bottom of the guide rail. The first abutting block drives the second abutting block to continue moving towards the convex platform. The abutting rod will push the second abutting block to slide upwards, so that the second abutting block abuts at the included angle between the convex platform and the bottom surface of the guide rail, and supports the guide rail at the bottom of the guide rail through the abutting rod; in order to enable the second abutting block to abut on the convex platform and slide upwards, springs or torsion springs are arranged at both ends of the connecting rod, so that the position of the second abutting block is higher than the position of the first abutting block. In this way, the second abutting block abuts at the bottom of the guide rail for support, and the position of the second abutting block is limited by the convex platform at the bottom of the guide rail, so that the second abutting block can support the guide rail on the second seal through the abutting rod and the first abutting block, increasing the stability of the guide rail supported in the gas quenching chamber.

[0027] In summary, the present invention includes at least one of the following beneficial technical effects: By performing cryogenic treatment on the heat-treated workpiece, the content of martensite in the workpiece can be increased, thereby increasing the hardness of the workpiece.

[0028] When heat-treating and cryogenic-treating the workpiece, it is carried out in different temperature stages and a reasonable temperature gradient is set, which can reduce the thermal stress in the workpiece, thereby reducing the probability of workpiece cracking and deformation and improving the yield rate of the workpiece.

[0029] By setting up a special quenching furnace, when quenching the workpiece in a vacuum environment, the gas quenching chamber and oil quenching chamber of the quenching furnace are isolated by using the first sealing component and the second sealing component respectively. On the one hand, it can reduce the contact between the oil mist in the oil quenching chamber and the workpiece during gas quenching, reducing the probability of generating oil stains or abnormal spots on the workpiece surface and improving the surface finish of the workpiece; on the other hand, it can reduce the diffusion of oil vapor generated at high temperature into the gas quenching chamber during oil quenching, reducing the pollution inside the gas quenching chamber and improving the cleanliness inside the gas quenching chamber.

[0030] Set up a connecting rod assembly to connect the first sealing member for moving sealing in the first sealing assembly with the guide rail. The connecting rod assembly can not only act as a driving device to drive the guide rail to drive the workpiece to move, but also realize the synchronous movement of the guide rail and the first sealing member. Brief Description of the Drawings

[0031] Figure 1 is the quenching process method diagram of Embodiment 1 of the present invention; Figure 2 is the overall structural schematic diagram of the quenching device of Embodiment 2 of the present invention; Figure 3 is the first working state schematic diagram of the first sealing assembly and the second sealing assembly of Embodiment 2 of the present invention; Figure 4 is the second working state schematic diagram of the first sealing assembly and the second sealing assembly of Embodiment 2 of the present invention; Figure 5 is the structural explosion schematic diagram of the first sealing assembly and the second sealing assembly of Embodiment 2 of the present invention.

[0032] Description of the Reference Numerals: 100, furnace body; 200, heating chamber; 300, quenching chamber; 310, gas quenching chamber; 320, oil quenching chamber; 330, guide rail; 331, convex platform; 400, first sealing assembly; 410, first support member; 420, first driving member; 430, first sealing member; 500, second sealing assembly; 510, second support member; 530, second driving member; 600, connecting rod assembly; 610, first rotating shaft; 620, second rotating shaft; 630, connecting rod; 700, support assembly; 710, first abutting block; 720, second abutting block; 730, abutting rod. Detailed Description of the Embodiments

[0033] The following will be combined with Figures 1 to 5 to further elaborate on the present invention in detail.

[0034] Example 1: An embodiment of the present invention discloses a quenching process. Refer to Figure 1 A quenching process sequentially includes a heating step, a quenching step, a tempering step, and a cryogenic cooling step. Among them, the heating step is divided into five stages. The temperature of the workpiece is increased to above Ac3 in five successive stages, causing the metallographic structure of the workpiece to transform towards austenite. Secondly, a special quenching oil is used to quench the workpiece, causing the metallographic structure of the workpiece to transform towards martensite. Thirdly, the workpiece is tempered to eliminate the internal thermal stress of the workpiece. Finally, the workpiece is subjected to an emergency cooling step. The emergency cooling step is divided into three steps. The temperature of the workpiece is sequentially reduced to -150 °C through three steps, causing the retained austenite inside the workpiece to continue to transform towards martensite, thereby enhancing the hardness of the workpiece.

[0035] Specifically, when heat-treating the workpiece, the following process is sequentially performed: S1: Place the workpiece in the heating chamber of a vacuum quenching furnace and evacuate the inside of the vacuum quenching furnace to a vacuum state; S2: Raise the temperature in the heating chamber to 200 °C and maintain it for 1 hour; S3: Raise the temperature in the heating chamber to 400 °C and maintain it for 1.2 hours; S4: Raise the temperature in the heating chamber to 500 °C and maintain it for 1.5 hours; S5: Raise the temperature in the heating chamber to 600 °C and maintain it for 1.8 hours; S6: Raise the temperature in the heating chamber to 900 °C and maintain it for 2 hours; S7: Move the workpiece from the heating chamber of the vacuum heating furnace to the quenching chamber of the vacuum heating furnace and quench the workpiece with a special quenching oil to cool the workpiece to below 230 °C; S8: Move the workpiece from the quenching chamber of the vacuum heating furnace to the heating chamber of the vacuum heating furnace and raise the temperature in the heating chamber to between 200 °C and 400 °C and maintain it for 4 hours. The temperature in the heating chamber in step S8 is adjusted according to the thickness of the workpiece. The greater the thickness of the workpiece, the higher the set temperature inside the heating chamber. Conversely, the smaller the thickness of the workpiece, the lower the set temperature inside the heating chamber. Specifically, for thin workpieces with a radius or thickness between 10 mm and 20 mm, the temperature increases by 5 °C for every 1 mm increase in thickness; for medium-thick workpieces with a radius or thickness between 20 mm and 40 mm, the temperature increases by 3 °C for every 1 mm increase in thickness; for thick workpieces with a radius or thickness between 40 mm and 60 mm, the temperature increases by 2 °C for every 1 mm increase in thickness; S9: Take out the workpiece from the vacuum heating furnace and place it in a special cryogenic cooling box, set the temperature in the cryogenic cooling box to -50 °C, and keep it warm for 5 hours S10: Set the temperature in the cryogenic chamber to -100 °C and keep it warm for 5 hours; S11: Set the temperature in the cryogenic chamber to -150 °C and keep it warm for 6 hours; In steps S9 to S11, liquid nitrogen is used to cool the cryogenic chamber. Specifically, a liquid nitrogen injection device can be used, and the internal temperature of the cryogenic chamber can be controlled by controlling the injection rate of liquid nitrogen.

[0036] Example 2: Refer to Figures 2 to 5 , this embodiment provides a quenching device. The quenching device includes a furnace body 100, a heating chamber 200 arranged inside the furnace body 100, and a quenching chamber 300 arranged inside the furnace body 100. The quenching chamber 300 includes a gas quenching chamber 310 and an oil quenching chamber 320. A first sealing component 400 and a second sealing component 500 are arranged between the gas quenching chamber 310 and the oil quenching chamber 320, and a guide rail 330 is arranged inside the gas quenching chamber 310. During operation, the workpiece and the material cart are placed on the guide rail 330, and the material cart drives the workpiece to move to the heating chamber 200 or the quenching chamber 300.

[0037] The quenching device adopted in this embodiment is a vacuum quenching device. The furnace body 100 is internally connected with a vacuum extraction device. When the heating chamber 200 or the quenching chamber 300 inside the furnace body 100 is working, the inside of the furnace body 100 needs to be pumped into a vacuum state.

[0038] When the workpiece is quenched in the quenching chamber 300, when the workpiece is working in the gas quenching chamber 310, the workpiece is supported on the guide rail 330 of the gas quenching chamber 310. The second sealing component 500 is located below the guide rail 330, and the second sealing component 500 is closed to isolate and seal the gas quenching chamber 310 and the oil quenching chamber 320. When the workpiece is working in the oil quenching chamber 320, the second sealing component 500 is opened, and the workpiece descends into the oil quenching chamber 320 along with the guide rail 330. At this time, both the first sealing component 400 and the second sealing component 500 are located above the guide rail 330, and the first sealing component 400 is closed to isolate and seal the gas quenching chamber 310 and the oil quenching chamber 320 Refer to Figures 3 to 5 , where there are two groups of the first sealing components 400. The two groups of the first sealing components 400 are arranged at both ends of the guide rail 330 along the length direction of the guide rail 330, and the two groups of the first sealing components 400 are arranged oppositely. Specifically, the first sealing component 400 includes a first support member 410, a first driving member 420, and a first sealing member 430. The first support member 410 is fixedly arranged on the inner wall of the gas quenching chamber 310, and the first support member 410 is arranged along the length direction of the guide rail 330. The first sealing member 430 is slidably arranged on the first support member 410, and the first driving member 420 is fixedly arranged on the first support member 410. The first driving member 420 is used to drive the first sealing member 430 to move along the direction of the first support member 410.

[0039] In this embodiment, the first driving member 420 is driven by the cooperation of a lead screw and a nut. Specifically, a chute is provided on the upper end surface of the first support member 410, and the chute is arranged along the length direction of the first support member 410. A slider is provided at the bottom of the first seal member 430, and the slider is arranged in cooperation with the chute. The lead screw is arranged in the chute along the length direction of the first support member 410. The nut is fixedly arranged on the slider through a bolt, and the lead screw passes through the nut. Installing a motor at the end of the lead screw to drive the lead screw to rotate can control the first seal member 430 to extend along the first support member 410. After the first seal members 430 arranged oppositely at both ends of the guide rail 330 extend out and abut against each other, they can be sealed.

[0040] In order to save space and increase the stability of the material cart moving on the guide rail 330 and the first seal member 430, a track is provided above the first seal member 430, and the track is arranged corresponding to the guide rail 330, so that the material cart can move on the first seal member 430 and the guide rail 330. When the gas quenching chamber 310 is working, the first sealing assembly 400 is arranged at both ends of the guide rail 330, and the guide rail 330 is flush with the track on the first seal member 430.

[0041] Refer to Figures 3 to 5 , the guide rail 330 is installed on the first seal member 430 through a connecting rod assembly 600. The connecting rod assembly 600 includes a first rotating shaft 610, a second rotating shaft 620 and a connecting rod 630. The first rotating shaft 610 is fixedly arranged on the side of the first support member 410, the second rotating shaft 620 is fixedly arranged on the side of the guide rail 330, one end of the connecting rod 630 is rotatably connected to the first rotating shaft 610, and the other end of the connecting rod 630 is rotatably connected to the second rotating shaft 620. When the first seal members 430 arranged oppositely on both sides of the guide rail 330 move towards the relatively close direction, the positions of the first rotating shafts 610 approach each other, the connecting rod 630 rotates accordingly, and the guide rail 330 moves downward under the action of gravity. The guide rail 330 drives the workpiece to move into the oil quenching chamber 320 below; when the first seal members 430 arranged oppositely on both sides of the guide rail 330 move towards the relatively far direction, the positions of the first rotating shafts 610 move away from each other, the connecting rod 630 rotates accordingly and pulls the guide rail 330 upward, so that the guide rail 330 drives the workpiece to rise into the gas quenching chamber 310; in order to increase the supporting force provided by the connecting rod 630 to the guide rail 330 upward, when the first seal member 430 is flush with the guide rail 330, the connecting rod 630 is arranged obliquely, so that the end of the connecting rod 630 connected to the first rotating shaft 610 is lower than the other end.

[0042] Refer to Figures 3 to 5, there are two sets of second sealing components 500, and the two sets of second sealing components 500 are oppositely arranged on both sides of the guide rail 330. The second sealing component 500 includes a second support member 510, a second driving member 530 and a second sealing member. The second support member 510 is fixedly arranged on the inner wall of the oil quenching chamber 320. The second support member 510 is arranged along the length direction of the guide rail 330. The second sealing member is fixedly arranged on the second support member 510. The second driving member 530 is fixedly arranged on the second support member 510. The second driving member 530 is used to drive the second sealing member to move along the direction of the second support member 510.

[0043] In this embodiment, the structure of the second driving member 530 is the same as that of the first driving member 420. In order to increase the sealing performance of the first sealing member 430 and the second sealing member,

[0044] Refer to Figures 3 to 5 , a support assembly 700 is arranged above the second sealing member. When the second sealing assembly 500 is closed, the support assembly 700 is used to support under the guide rail 330. The support assembly 700 includes a first abutting block 710, a second abutting block 720 and an abutting rod 730. The first abutting block 710 is fixedly arranged on the second sealing member. One end of the abutting rod 730 is rotatably connected to the first abutting block 710. The second abutting block 720 is rotatably installed at the other end of the abutting rod 730. Correspondingly, a boss 331 is arranged at the bottom of the guide rail 330. When the second sealing assembly 500 is closed, the second abutting block 720 abuts at the included angle between the boss 331 and the bottom surface of the guide rail 330 to support the guide rail 330.

[0045] In order to enable the second abutting block 720 to abut against the boss 331 and when the second abutting block 720 moves in the direction close to the boss 331, enable the second abutting block 720 to slide upward, springs or torsion springs are arranged at both ends of the connecting rod, so that the second abutting block 720 has a tendency to slide upward, and the position of the second abutting block 720 is higher than the position of the first abutting block 710. In this embodiment, torsion springs are arranged at both ends of the abutting rod 730 to make the second abutting block 720 slide and abut against the bottom of the guide rail 330 or the first sealing member 430. When the second sealing member is closed, the second abutting block 720 abuts against the bottom of the first sealing member 430 for support. When the second sealing member is opened, the second abutting block 720 slides and abuts against the bottom of the first support member 410.

[0046] The implementation principle of a quenching device according to an embodiment of the present invention is as follows: When the workpiece needs to be gas quenched, the workpiece is supported on the guide rail 330. The guide rail 330 is supported by the connecting rod assembly 600 and the support assembly 700 to be flush with the first seal 430, and the second seal closes below the guide rail 330 for sealing; when the workpiece needs to be oil quenched, the workpiece is supported on the guide rail 330, the second seal assembly 500 is opened, and the first seal assembly 400 is closed. When the first seal assembly 400 is closed, the first seal 430 moves in a relatively closer direction. Under the action of gravity and the connecting rod assembly 600, the guide rail 330 drives the workpiece to move downward and enter the oil quenching chamber 320. When the first seals 430 at both ends of the guide rail 330 move to the ends and abut against each other, the first seal assembly 400 completes the sealing, and the guide rail 330 moves to the lowest position for oil quenching.

[0047] In summary, performing cryogenic treatment on the heat-treated workpiece according to the present invention can increase the content of martensite in the workpiece, thereby increasing the hardness of the workpiece. When performing heat treatment and cryogenic treatment on the workpiece, different temperature stages are divided, and a reasonable temperature gradient is set, which can reduce the thermal stress in the workpiece, thereby reducing the probability of workpiece cracking and deformation and improving the yield rate of the workpiece; when using a quenching furnace to quench the workpiece, the first seal assembly 400 and the second seal assembly 500 are used to isolate the gas quenching chamber 310 and the oil quenching chamber 320 of the quenching furnace. On the one hand, it can reduce the contact between the oil mist in the oil quenching chamber 320 and the workpiece during gas quenching, reducing the probability of generating oil stains or abnormal spots on the surface of the workpiece and improving the surface finish of the workpiece; on the other hand, it can reduce the diffusion of oil vapor generated at high temperature into the gas quenching chamber 310 during oil quenching, reducing the pollution inside the gas quenching chamber 310 and improving the cleanliness inside the gas quenching chamber 310.

[0048] The above are all the preferred embodiments of the present invention. The protection scope of the present invention is not limited by this. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A quenching process, characterized in that: 依次包括升温步骤、淬火步骤、回火步骤、深冷步骤: 升温步骤:分阶段对工件进行升温保温,并最终将工件加热至Ac3以上进行保温,得到奥氏体; 淬火步骤:快速将工件降温至Ms以下,使奥氏体转变为马氏体; 回火步骤:将工件二次升温至200 degrees Celsius to 400 degrees Celsius, and hold for more than 4 hours to eliminate the internal stress of the workpiece; 急冷步骤,依次包括预冷步骤、中冷步骤和深冷步骤: 预冷步骤:将工件降温至-50 degrees Celsius, and hold for 5 hours; 中冷步骤:将工件降温至-100 degrees Celsius, and hold for 5 hours; 深冷步骤:将工件降温至-150 degrees Celsius, and hold for 6 hours.

2. A quenching process according to claim 1, characterized in that: 升温步骤依次包括五个阶段: 第一阶段:将工件升温至200 degrees Celsius, and the holding time is T1; 第二阶段:将工件升温至400 degrees Celsius, and the holding time is T2; 第三阶段:将工件升温至500 degrees Celsius, and the holding time is T3; 第四阶段:将工件升温至600 degrees Celsius, and the holding time is T4; 第五阶段:将工件升温至900 degrees Celsius or above, and the holding time is T5; 且1 hour < T1 < T2 < T3 < T4 < T5 < 2 hours.

3. A quenching process according to claim 2, characterized in that: 升温步骤和淬火步骤均在真空环境中进行。 4. A quenching process according to claim 2, characterized in that: 淬火步骤采用专用淬火油进行淬火或采用惰性气体进行淬火。 5. A quenching device, comprising a furnace body (100), a heating chamber (200) arranged inside the furnace body (100), and a quenching chamber (300) arranged inside the furnace body (100), characterized in that a gas quenching chamber (310) and an oil quenching chamber (320) are arranged inside the quenching chamber (300), the gas quenching chamber (310) is arranged above the oil quenching chamber (320), a first sealing assembly (400) and a second sealing assembly (500) are arranged between the gas quenching chamber (310) and the oil quenching chamber (320), and a guide rail (330) is further arranged inside the gas quenching chamber (310), and the guide rail (330) is slidably installed in the gas quenching chamber (310) in the vertical direction; when the gas quenching chamber (310) works, the second sealing assembly (500) is closed, the gas quenching chamber (310) and the oil quenching chamber (320) are isolated and sealed, the guide rail (330) is located above the second sealing assembly (500), and the workpiece is supported on the guide rail (330); when the oil quenching chamber (320) works, the workpiece descends into the oil quenching chamber (320) along with the guide rail (330), the first sealing assembly (400) is located above the guide rail (330), and the first sealing assembly (400) is closed, and the gas quenching chamber (310) and the oil quenching chamber (320) are isolated and sealed.

6. A quenching device according to claim 5, characterized in that: The first sealing assembly (400) is provided with two groups, and the two groups of the first sealing assemblies (400) are arranged oppositely on both sides of the guide rail (330). The first sealing assembly (400) comprises a first support member (410), a first driving member (420) and a first sealing member (430). The first support member (410) is fixedly arranged on the inner wall of the gas quenching chamber (310). The first support member (410) is arranged along the length direction of the guide rail (330). The first sealing member (430) is slidably arranged on the first support member (410). The first driving member (420) is fixedly arranged on the first support member (410). The first driving member (420) is used to drive the first sealing member (430) to move along the direction of the first support member (410). The second sealing assembly (500) is provided in two groups, and the two groups of the second sealing assembly (500) are arranged oppositely on both sides of the guide rail (330). The second sealing assembly (500) comprises a second support member (510), a second driving member (530) and a second sealing member (540). The second support member (510) is fixedly arranged on the inner wall of the oil quenching chamber (320). The second support member (510) is arranged along the length direction of the guide rail (330). The second sealing member (540) is fixedly arranged on the second support member (510). The second driving member (530) is fixedly arranged on the second support member (510). The second driving member (530) is used to drive the second sealing member (540) to move along the direction of the second support member (510). The guide rail (330) is mounted on the first sealing member (430) via a connecting rod assembly (600), and the connecting rod assembly (600) is used to control the up and down movement of the guide rail (330).

7. A quenching device according to claim 6, characterized in that: The connecting rod assembly (600) comprises a first rotating shaft (610), a second rotating shaft (620) and a connecting rod (630); the first rotating shaft (610) is fixedly arranged on the first support member (410); the second rotating shaft (620) is fixedly arranged on the guide rail (330); one end of the connecting rod (630) is rotatably connected to the first rotating shaft (610); and the other end of the connecting rod (630) is rotatably connected to the second rotating shaft (620).

8. A quenching device according to claim 7, characterized in that: A track is arranged above the first sealing member (430); when the gas quenching chamber (310) is in operation, the first sealing assembly (400) is opened, and the guide rail (330) is flush with the track on the first sealing member (430); A support assembly (700) is provided above the second sealing member (540); when the second sealing member (500) is closed, the support assembly (700) is used to provide support below the guide rail (330), and at this time, one end of the connecting rod (630) connected to the first rotating shaft (610) is lower than the other end.

9. A quenching device according to claim 8, characterized in that: The support assembly (700) comprises a first abutment block (710), a second abutment block (720) and an abutment rod (730), wherein the first abutment block (710) is fixedly arranged on the second sealing member (540), one end of the abutment rod (730) is rotatably connected to the first abutment block (710), and the second abutment block (720) is rotatably mounted on the other end of the abutment rod (730); A boss (332) is provided at the bottom of the guide rail (330), and when the second sealing assembly (500) is closed, the second abutment block (720) abuts against the angle between the boss (332) and the bottom surface of the guide rail (330) to support the guide rail (330).

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