Annular furnace heat treatment production line with intermediate cooling and secondary heating functions and its process

Abstract

A ring furnace heat treatment production line with intermediate cooling and secondary heating functions and its process, wherein the ring furnace heat treatment production line includes a loading platform, a pre-oxidation furnace, a heating furnace, a push-plate diffusion furnace, a ring carburizing furnace, a double-station intermediate cooling chamber, a rotary bottom secondary heating furnace, a quenching oil tank, a cleaning machine and a discharge platform connected in sequence, the interior of the double-station intermediate cooling chamber is divided into a left cooling chamber, a right cooling chamber and a common channel, and the diffusion furnace discharge mechanism of the push-plate diffusion furnace can selectively push the workpiece after diffusion treatment to the common channel or the rotary bottom secondary heating furnace; when the workpiece is pushed to the common channel, the workpiece is sequentially intermediate cooled and secondary heated through the left and right cooling chambers and the rotary bottom secondary heating furnace, and then the workpiece is sent to the quenching oil tank; and when the workpiece is directly pushed into the rotary bottom secondary heating furnace, it can be sent to the quenching oil tank via the rotary bottom secondary heating furnace. Accordingly, the heat treatment requirements of different types of workpieces can be met, and the heat treatment efficiency of the workpiece can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of workpiece heat treatment, and in particular to a ring furnace heat treatment production line with intermediate cooling and secondary heating functions and a process thereof. Background Art

[0002] At present, the main process steps implemented by the annular furnace heat treatment production line are mostly heating, carburizing, diffusion, insulation, quenching or pressure quenching, etc., and for workpieces made of special metal materials, it is usually necessary to implement the process steps of intermediate cooling and secondary heating during the heat treatment process. However, if the existing annular furnace heat treatment production line is to implement the process steps of intermediate cooling and secondary heating, the workpiece can only be moved out of the annular furnace heat treatment production line after the workpiece completes the diffusion step and transferred to the intermediate cooling and secondary heating equipment to implement the relevant process steps, which leads to the discrete configuration of the production equipment, and the need to add additional auxiliary transfer equipment such as workpiece insulation transfer carriers and other auxiliary operations, and the entire heat treatment process cannot be implemented continuously, which not only increases the investment cost of manpower and material resources, but also makes the workpiece heat treatment efficiency relatively low. Therefore, how to integrate the intermediate cooling and secondary heating processes into the annular furnace heat treatment production line in an orderly manner to improve the integration of the overall production line, and enable the heat treatment process to be implemented in an orderly and coherent manner, and can also simultaneously meet the different heat treatment requirements of ordinary workpieces and special metal workpieces, thereby saving the investment cost of manpower and material resources and improving the heat treatment efficiency of the workpiece, has become one of the technical problems that need to be solved in this field. Summary of the invention

[0003] The technical problem to be solved by this technical solution is how to integrate the intermediate cooling and secondary heating process equipment into the annular furnace heat treatment production line in an orderly manner, so that the annular furnace heat treatment production line can not only meet the different heat treatment requirements of ordinary workpieces and special metal workpieces at the same time, but also enable the heat treatment process to be implemented in an orderly and coherent manner, thereby saving manpower and material investment costs and improving the heat treatment efficiency of the workpiece.

[0004] In order to solve the above technical problems, the present technical scheme provides a ring furnace heat treatment production line with intermediate cooling and secondary heating functions, which is used to selectively perform carburizing, intermediate cooling, secondary heating and quenching operations or perform carburizing and quenching operations on workpieces loaded in a tray. The ring furnace heat treatment production line includes: a loading platform, a pre-oxidation furnace, a heating furnace, a push-plate diffusion furnace, a ring carburizing furnace, a double-station intermediate cooling chamber, a rotary bottom secondary heating furnace, a quenching oil tank, a cleaning machine and a discharge platform, wherein the loading platform is connected to the feed port of the pre-oxidation furnace, and the discharge port of the pre-oxidation furnace is connected to the feed port of the pre-oxidation furnace by a lifting The charging mechanism is connected to the bottom charging section of the heating furnace. The two opposite side walls of the feeding end of the push-plate diffusion furnace are respectively provided with a heating inlet and a carburizing inlet that are aligned with each other. The discharge port of the heating furnace is sealed and connected to the heating inlet. The discharge port of the annular carburizing furnace is sealed and connected to the carburizing inlet. The interior of the double-station intermediate cooling chamber is divided into a left cooling chamber, a common channel and a right cooling chamber from one side to the other, and the two opposite side walls at both ends of the adjacent common channel of the double-station intermediate cooling chamber are respectively provided with an intermediate cooling chamber entrance and an intermediate cooling chamber exit that are connected to the common channel. A diffusion discharge port is provided on one side wall of the discharge end of the bulk furnace, the entrance of the intermediate cooling chamber is sealed and connected to the diffusion discharge port, the secondary heating inlet of the rotary bottom secondary heating furnace is sealed and connected to the outlet of the intermediate cooling chamber, the secondary heating discharge port of the rotary bottom secondary heating furnace is sealed and connected to the inlet of the quenching oil tank, the discharge port of the quenching oil tank is connected to the inlet of the cleaning machine, and the discharge port of the cleaning machine is connected to the discharge platform; during operation, according to the heat treatment requirements of different types of workpieces, the diffusion furnace discharge mechanism of the push-plate diffusion furnace can selectively push the workpieces after carburizing diffusion treatment to the public The workpiece is pushed onto the common channel or directly into the rotary bottom secondary heating furnace, wherein when the workpiece is pushed onto the common channel by the discharging mechanism of the diffusion furnace, the workpiece is moved into the left cooling chamber or the right cooling chamber for intermediate cooling treatment, and then the discharging mechanism of the diffusion furnace pushes the workpiece after the intermediate cooling treatment into the rotary bottom secondary heating furnace for secondary heating treatment, and then the workpiece after the secondary heating treatment is sent to the quenching oil tank for quenching treatment, and when the workpiece is directly pushed into the rotary bottom secondary heating furnace by the discharging mechanism of the diffusion furnace, the workpiece is sent into the quenching oil tank for quenching treatment through the rotary bottom secondary heating furnace. Accordingly, a double-station intermediate cooling chamber and a rotary bottom type secondary heating furnace are sequentially added between the push-plate diffusion furnace and the quenching oil tank of the annular furnace heat treatment production line, and the diffusion furnace discharge mechanism of the push-plate diffusion furnace can selectively push the workpieces to the common channel or directly push them into the rotary bottom type secondary heating furnace according to the heat treatment requirements of different types of workpieces, so as to selectively perform intermediate cooling, secondary heating and quenching treatment on the workpieces after diffusion treatment, or directly perform quenching treatment; in addition, since the double-station intermediate cooling chamber has two left and right cooling chambers, it can perform intermediate cooling operation on two workpieces at the same time, and the rotary bottom type secondary heating furnace can also perform secondary heating operation on multiple workpieces at the same time, thereby enabling the annular furnace heat treatment production line to have continuous heat treatment capacity like an assembly line and have higher heat treatment efficiency.

[0005] As another implementation of the technical solution, the double-station intercooling chamber is mainly composed of an intercooling chamber shell, an intercooling chamber lining, a pair of public channel guide rails, two pairs of intercooling chamber guide rails, two push-pull material mechanisms, two high-temperature fans, two air guide muffles, two lifting air guide doors, two heat exchange mechanisms, two protective atmosphere gas supply pipelines and exhaust gas exhaust pipelines, wherein the intercooling chamber shell is covered on the outside of the intercooling chamber lining, and the interior of the intercooling chamber lining is divided into the left cooling chamber, the public channel and the right cooling chamber from one side to the other side, the intercooling chamber shell and the intercooling chamber The furnace lining is combined to form a furnace body structure of a double-station intermediate cooling chamber, and an intermediate cooling chamber entrance and an intermediate cooling chamber exit communicating with a common channel are respectively opened on two opposite sides thereof, the pair of common channel guide rails is fixedly laid on the bottom of the common channel along the direction from the intermediate cooling chamber entrance to the intermediate cooling chamber exit, the two pairs of intermediate cooling chamber guide rails are perpendicular to the pair of common channel guide rails and are respectively fixedly laid on the bottom of the left cooling chamber and the right cooling chamber, the two pushing and pulling material mechanisms are respectively fixedly installed on the outer sides of the other two opposite side walls perpendicular to the side wall with the intermediate cooling chamber entrance, and the other The positions of the push-pull material heads of the two push-pull material mechanisms are respectively provided with material head openings on the two opposite side walls to allow the push-pull material heads to enter and exit. The two high-temperature fans are respectively installed on the tops of the left cooling chamber and the right cooling chamber. The two air guide muffles are respectively covered on the middle cooling chamber guide rails of the left cooling chamber and the right cooling chamber and are communicated with the high-temperature fans. The two air guide muffles are respectively provided with inlets and outlets on the sides facing the public passage. The two lifting air guide doors are respectively provided at the inlets and outlets of the two air guide muffles. The two heat exchange mechanisms are respectively provided at the left cooling chamber and the right cooling chamber. On both sides of the indoor air guide muffle, the two protective atmosphere air supply pipelines are respectively arranged on the top outer side of the left cooling chamber and the right cooling chamber and communicated with the inside of the left cooling chamber and the right cooling chamber. The exhaust gas discharge pipeline is arranged on the top outer side of the common channel adjacent to the entrance of the intermediate cooling chamber and communicated with the inside of the common channel. The push-pull head of the push-pull material mechanism is used to pull the workpiece placed on the guide rail of the common channel into the left cooling chamber or the right cooling chamber to perform intermediate cooling treatment on the workpiece, and then the workpiece is pushed back to the guide rail of the common channel by the push-pull material head to complete the intermediate cooling treatment of the workpiece.

[0006] As another implementation of the present technical solution, the heat exchange mechanism is mainly composed of two groups of heat exchange coils, two groups of heat exchange fins and a heat exchange medium driving device, wherein the two groups of heat exchange coils are respectively fixedly arranged in the space between the two sides of the air guide muffle and the two side walls of the intermediate cooling chamber lining, and the medium inlet end and the medium outlet end of the heat exchange coil both pass through the top of the double-station intermediate cooling chamber, the two groups of heat exchange fins are respectively installed on the two groups of heat exchange coils, and the heat exchange medium driving device is arranged on the outside of the double-station intermediate cooling chamber. When the heat exchange medium is outside air, the heat exchange medium driving device is an exhaust fan, and the medium outlet end is connected to the suction end of the exhaust fan, and the medium inlet end is connected to the external environment; in addition, when the heat exchange medium is cooling oil, the heat exchange medium driving device is composed of a replenishing oil tank and a circulating oil pump connected to each other, the medium inlet end is connected to the pump outlet end of the circulating oil pump, and the medium outlet end is connected to the replenishing oil tank. Accordingly, the heat exchange mechanism can cool down the workpiece in the cooling chamber by air cooling or oil cooling.

[0007] As another implementation of the present technical solution, the rotary bottom secondary heating furnace is mainly composed of a secondary heating furnace shell, a secondary heating furnace lining, a circular rotary bottom, a plurality of material tray brackets, a rotary bottom driving device, a plurality of radiation heating tubes, a plurality of high-temperature fans, a protective atmosphere gas supply pipeline, an exhaust gas exhaust pipeline, an observation window and an inspection door, wherein the secondary heating furnace shell is covered on the outside of the secondary heating furnace lining to combine to form the furnace body structure of the rotary bottom secondary heating furnace, the interior of the secondary heating furnace lining forms a circular furnace cavity, and two opposite sides of the rotary bottom secondary heating furnace body structure are respectively provided with a secondary heating inlet and a secondary heating outlet communicated with the circular furnace cavity, and the bottom of the circular furnace cavity A circular rotary bottom is installed at the bottom, and the multiple material tray brackets are arranged at intervals and evenly on the upper side of the circular rotary bottom. The rotary bottom driving device is arranged below the circular rotary bottom and is connected to the circular rotary bottom drive to drive the circular rotary bottom to rotate in a circumferential direction. The multiple radiation heating tubes are evenly arranged in a circle in the circular furnace cavity. The multiple high-temperature fans are evenly arranged in a circle on the upper part of the circular furnace cavity. The protective atmosphere supply pipeline is arranged on the top outer side of the circular furnace cavity and communicated with the inside of the circular furnace cavity. The exhaust gas exhaust pipeline is arranged on the top outer side of the circular furnace cavity adjacent to the secondary heating material inlet and communicated with the inside of the circular furnace cavity. The observation window and the inspection door are arranged on the furnace body structure of the rotary bottom secondary heating furnace and communicated with the inside of the circular furnace cavity.

[0008] As another implementation of the technical solution, the heating furnace is composed of a bottom loading section and a sealed heating section that are sealed together. The height of the discharge port of the pre-oxidation furnace is lower than the height of the bottom loading section. The bottom of the bottom loading section is provided with a bottom loading port and is surrounded by a fire curtain. The lifting and loading mechanism is provided below the bottom loading port and aligned with the discharge port of the pre-oxidation furnace. The workpiece after pre-oxidation treatment is moved to the lifting and loading mechanism through the discharge port of the pre-oxidation furnace, and then the lifting and loading mechanism lifts the workpiece and moves it into the bottom loading section through the bottom loading port, and then moves the workpiece to the sealed heating section for heating treatment. Accordingly, the bottom loading structure of the heating furnace and the setting of the fire curtain can effectively prevent the entry of external air during the feeding stage, thereby preventing the occurrence of safety risks such as deflagration and explosion.

[0009] As another implementation of the technical solution, the feed inlet and discharge port of the pre-oxidation furnace are equipped with lifting furnace doors, and sealed lifting furnace doors are installed between the bottom loading section and the sealed heating section, between the discharge port of the heating furnace and the heating feed port, between the discharge port and the carburizing feed port, between the diffusion discharge port and the intermediate cooling chamber entrance, between the intermediate cooling chamber outlet and the secondary heating feed port, and between the secondary heating discharge port and the quenching oil tank feed port. In this way, the heating and heat preservation operation of the pre-oxidation furnace is ensured, and the safe operation of the heating furnace, the push-plate diffusion furnace, the annular carburizing furnace, the double-station intermediate cooling chamber and the rotary bottom secondary heating furnace in a protective atmosphere environment is ensured.

[0010] As another implementation of the technical solution, a guide rod pushing device consisting of a pressure-driven cylinder and a push rod is installed on one end of the loading platform relative to the feed port of the pre-oxidation furnace, the outer side of the furnace wall of the pre-oxidation furnace relative to its discharge port, the outer side of the furnace wall of the bottom loading section relative to the sealed heating section, and the outer side of the furnace wall of the feed end of the push-plate diffusion furnace, while the discharge device installed on the outer side of the furnace wall of the heating furnace relative to its discharge port and the discharge mechanism of the diffusion furnace are both guide chain pushing devices consisting of a winding chain track, a chain, a push head, a driving motor and a sprocket, and a workpiece supporting device is installed on the outer side of the inner ring side furnace wall of the annular carburizing furnace relative to its feed port and the outer side of the quenching oil tank relative to its feed port. Accordingly, the workpiece is pushed and transferred between the entire production line and its various process equipment through the above-mentioned workpiece transfer device.

[0011] As another implementation of the technical solution, the annular furnace heat treatment production line further includes: a tempering furnace and an air cooling table, which are sequentially connected between the cleaning machine and the discharge table. Accordingly, the annular furnace heat treatment production line can have tempering and air cooling process links.

[0012] As another implementation of the technical solution, the cleaning machine is composed of an alkaline water soaking position, a clean water spraying position and a drying position arranged in sequence, thereby being able to thoroughly clean the workpiece after quenching.

[0013] In order to solve the above technical problems, the present technical solution also provides a process for heat treatment of workpieces using the above annular furnace heat treatment production line with intermediate cooling and secondary heating functions, the steps of which include: Pre-oxidation step: the workpieces loaded in several trays are transferred to the pre-oxidation furnace through the loading platform for pre-oxidation treatment; Heating step: the workpiece after pre-oxidation treatment is transferred to the heating furnace through the lifting and loading mechanism for heating treatment in a protective atmosphere environment; Carburizing step: the workpiece after heating is transferred to the annular carburizing furnace for carburizing treatment in a protective atmosphere; Diffusion step: the carburized workpiece is transferred to a push-plate diffusion furnace for diffusion treatment in a protective atmosphere; Process selection steps: when it is necessary to perform intermediate cooling and secondary heating treatment on the workpiece after diffusion treatment, the diffusion furnace discharge mechanism of the push-plate diffusion furnace pushes the workpiece to the common channel of the double-station intermediate cooling chamber, the workpiece is moved into the left cooling chamber or the right cooling chamber and performs intermediate cooling treatment under a protective atmosphere, the workpiece after intermediate cooling treatment is moved back to the common channel, and then the diffusion furnace discharge mechanism pushes the workpiece to the rotary bottom secondary heating furnace for secondary heating treatment under a protective atmosphere; or when it is necessary to directly perform quenching treatment on the workpiece after diffusion treatment, the diffusion furnace discharge mechanism pushes the workpiece directly to the rotary bottom secondary heating furnace for transfer; Quenching step: the workpiece after secondary heating treatment or diffusion treatment is transferred to the quenching oil tank for quenching treatment; Cleaning step: the workpiece after quenching is transferred to the cleaning machine for cleaning; Discharging step: The workpiece after cleaning is transferred to the discharging platform for discharging.

[0014] Accordingly, the above process can simultaneously meet the different heat treatment requirements of ordinary workpieces and special metal workpieces, and can ensure the orderly and coherent implementation of each step in the process, thereby saving manpower and material investment costs and improving the heat treatment efficiency of the workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a top view schematic diagram of the annular furnace heat treatment production line with intermediate cooling and secondary heating functions of the present invention; Figure 2 It is a top view schematic diagram of the sealed connection between the double-station intermediate cooling chamber and the rotary bottom secondary heating furnace in the present invention; Figure 3 It is a side cross-sectional view of the sealing connection of the push-plate diffusion furnace, the double-station intermediate cooling chamber, the rotary bottom secondary heating furnace and the quenching oil tank in the present invention; Figure 4a It is a structural schematic diagram of a push-pull material head for push-pull operation at the bottom of the material tray; Figure 4b It is a schematic diagram of the structure of the push-pull material head for the push-pull operation of the material tray edge; Figure 5 It is a side cross-sectional view of the bottom charging section of the heating furnace in the present invention; Figure 6 It is a side sectional view of the workpiece supporting device in the present invention; Figure 7 It is a side cross-sectional view of the quenching oil tank in the present invention.

[0016] Explanation of symbols in the accompanying drawings: 1 Loading platform; 2 Pre-oxidation furnace; 3 Heating furnace; 31 Bottom charging section; 311 Bottom charging port; 32 Sealed heating section; 33 Lifting charging mechanism; 4 Push-disk diffusion furnace; 5 Annular carburizing furnace; 6 Double-station intercooling chamber; 611 Intercooling chamber shell; 612 Intercooling chamber lining; 621 Left cooling chamber; 622 Public channel; 623 Right cooling chamber; 624 Public channel guide rail; 625 Intercooling chamber guide rail; 63 Push-pull mechanism; 631 Push-pull head; 64 High-temperature fan; 65 Air guide muffle; 66 Lifting air guide door; 67 Heat exchange mechanism; 7 Rotary bottom secondary heating furnace; 711 Secondary heating furnace shell; 712 Secondary heating furnace lining; 72 Round rotary bottom; 73 Feed tray bracket; 74 Radiant heating tube; 75 High-temperature fan; 76 Observation window; 77 Inspection door; 8 Quenching oil tank; 81 Sealed front chamber; 82 Discharging chamber; 83 Quenching oil pool; 84 Workpiece quenching moving mechanism; 9 Cleaning machine; 10 Discharging table; 11 Tempering furnace; 12 Air cooling table; 13 Lifting furnace door; 14 Sealed lifting furnace door; 15 Guide rod pushing device; 16 Guide chain pushing device; 17 Workpiece supporting device; 171 Supporting mechanism housing; 172 Opening; 173 Pushing drive motor; 174 Screw; 175 Material fork seat; 176 Material fork; 177 Support connecting rod; 178 Lifting drive motor; 179 Eccentric cam; A Workpiece; B Material tray. DETAILED DESCRIPTION

[0017] The detailed description and technical contents of the present invention are described as follows with reference to the accompanying drawings. However, the accompanying drawings are only provided for reference and description and are not intended to limit the present invention.

[0018] In the context of this specification, any two or more embodiments of the present invention may be arbitrarily combined, and the technical solutions thus formed belong to part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0019] like Figure 1The figure shows a schematic diagram of a specific embodiment of the annular furnace heat treatment production line with intermediate cooling and secondary heating functions of the present invention. The annular furnace heat treatment production line with intermediate cooling and secondary heating functions (hereinafter referred to as the annular furnace heat treatment production line) is used to selectively perform carburizing, intermediate cooling, secondary heating and quenching operations or perform carburizing and quenching operations on the workpieces contained in the material tray. The annular furnace heat treatment production line includes a loading platform 1, a pre-oxidation furnace 2, a heating furnace 3, a push-plate diffusion furnace 4, an annular carburizing furnace 5, a double-station intermediate cooling chamber 6, a rotary bottom secondary heating furnace 7, a quenching oil tank 8, a cleaning machine 9 and a discharge platform 10, wherein the loading platform 1 is connected to the feed port of the pre-oxidation furnace 2, and the discharge port of the pre-oxidation furnace 2 is connected to the bottom loading section 31 of the heating furnace 3 through a lifting loading mechanism 33 (combined with Figure 5 As shown in FIG. 1 ), the two opposite side walls of the feeding end of the push-plate diffusion furnace 4 are respectively provided with a heating inlet and a carburizing inlet which are aligned with each other. The discharge port of the heating furnace 3 is sealed and connected to the heating inlet. The discharge port of the annular carburizing furnace 5 is sealed and connected to the carburizing inlet. Figure 2As shown, the interior of the double-station intermediate cooling chamber 6 is divided into a left cooling chamber 621, a common channel 622 and a right cooling chamber 623 in sequence from one side to the other, and an intermediate cooling chamber entrance and an intermediate cooling chamber exit communicating with the common channel 622 are respectively provided on two opposite side walls at both ends of the adjacent common channel 622 of the double-station intermediate cooling chamber 6, a diffusion outlet is provided on one side wall of the discharge end of the push-plate diffusion furnace 4, the intermediate cooling chamber entrance is sealedly connected to the diffusion outlet, the secondary heating inlet of the rotary bottom secondary heating furnace 7 is sealedly connected to the intermediate cooling chamber outlet, the secondary heating outlet of the rotary bottom secondary heating furnace 7 is sealedly connected to the inlet of the quenching oil tank 8, the outlet of the quenching oil tank 8 is connected to the inlet of the cleaning machine 9, and the outlet of the cleaning machine 9 is connected to the discharge platform 10. Among the various devices constituting the annular furnace heat treatment production line of the present invention, the loading platform 1, pre-oxidation furnace 2, heating furnace 3, push plate diffusion furnace 4, annular carburizing furnace 5, rotary bottom secondary heating furnace 7, quenching oil tank 8, cleaning machine 9 and unloading platform 10 are all commonly used in existing workpiece heat treatment production lines. Among them, the heating furnace 3, push plate diffusion furnace 4, annular carburizing furnace 5, rotary bottom secondary heating furnace 7 and quenching oil tank 8 are all isolated from the outside world and operated in a closed environment with a protective gas atmosphere (usually nitrogen) to implement the corresponding process. The rotary bottom secondary heating furnace 7 is an existing heating furnace type, which is often used as a heating furnace in other existing heat treatment production lines, but is used for secondary heating of workpieces in the present invention. The biggest difference between the annular furnace heat treatment production line of the present invention and other existing workpiece heat treatment production lines is that a rotary bottom heating furnace is used as a secondary heating furnace, and a double-station intermediate cooling chamber 6 with an original structure is also arranged between the push-plate diffusion furnace 4 and the rotary bottom secondary heating furnace 7, and the diffusion furnace discharging mechanism of the push-plate diffusion furnace 4 is used to selectively push the workpiece A after diffusion treatment to the double-station intermediate cooling chamber 6 or the rotary bottom secondary heating furnace 7, so as to achieve the purpose of implementing different process treatments on different types of workpieces A, and because the double-station intermediate cooling chamber 6 and the rotary bottom secondary heating furnace 7 can simultaneously implement process treatments on multiple workpieces A, the heat treatment efficiency of the annular furnace heat treatment production line of the present invention can be greatly improved.Accordingly, the annular furnace heat treatment production line of the present invention constituted by the above-mentioned equipment can, according to the heat treatment requirements of different types of workpieces A, selectively push the workpiece A after carburizing diffusion treatment to the common channel 622 or directly push it to the rotary bottom secondary heating furnace 7 by the diffusion furnace discharge mechanism of the push-plate diffusion furnace 4, wherein when the workpiece A is pushed to the common channel 622 by the diffusion furnace discharge mechanism, the workpiece A is moved into the left cooling chamber 621 or the right cooling chamber 623 for intermediate cooling treatment, and then the workpiece A after the intermediate cooling treatment is pushed by the diffusion furnace discharge mechanism to the rotary bottom secondary heating furnace 7 for secondary heating treatment, and then the workpiece A after the secondary heating treatment is sent to the quenching oil tank 8 for quenching treatment; and when the workpiece A is directly pushed to the rotary bottom secondary heating furnace 7 by the diffusion furnace discharge mechanism, the workpiece A is sent to the quenching oil tank 8 for quenching treatment through the rotary bottom secondary heating furnace 7. In order to save space, in the subsequent description, only the equipment structure with special or unique features in the annular furnace heat treatment production line is described in detail, and the existing equipment structure is not described in detail.

[0020] Specifically, combined Figure 2 and 3As shown, the double-station intermediate cooling chamber 6 is mainly composed of an intermediate cooling chamber shell 611, an intermediate cooling chamber furnace lining 612, a pair of common channel guide rails 624, two pairs of intermediate cooling chamber guide rails 625, two material pushing and pulling mechanisms 63, two high-temperature fans 64, two air guide muffles 65, two lifting air guide doors 66, two heat exchange mechanisms 67, two protective atmosphere gas supply pipelines (not shown) and an exhaust gas discharge pipeline (not shown). The intermediate cooling chamber shell 611 is covered on the outside of the intermediate cooling chamber furnace lining 612, and the inside of the intermediate cooling chamber furnace lining 612 is divided into the left cooling chamber 621, the common channel 622 and the right cooling chamber 623 from one side to the other side. The intermediate cooling chamber shell 611 and the intermediate cooling chamber furnace lining 612 are combined to form the furnace body structure of the double-station intermediate cooling chamber 6, and the two opposite sides thereof are respectively provided with an intermediate cooling chamber inlet and an intermediate cooling chamber outlet communicating with the common channel 622. The pair of common channel guide rails 624 is fixedly laid on the bottom of the common channel 622 along the direction from the intercooling chamber entrance to the intercooling chamber exit. The two pairs of intercooling chamber guide rails 625 are perpendicular to the pair of common channel guide rails 624 and are fixedly laid on the bottom of the left cooling chamber 621 and the right cooling chamber 623 respectively. The two push-pull material mechanisms 63 are respectively fixedly installed on the outer sides of the other two opposite side walls perpendicular to the side wall with the intercooling chamber entrance, and the other two opposite side walls are respectively provided with material head openings (marked in the figure) at the positions corresponding to the push-pull material heads of the two push-pull material mechanisms 63 for the push-pull material heads to enter and exit. The two high-temperature fans 64 are respectively installed on the top of the left cooling chamber 621 and the right cooling chamber 623. The two air guide muffles 65 are respectively covered on the intercooling chamber guide rails 625 of the left cooling chamber 621 and the right cooling chamber 623 and communicated with the high-temperature fans 64. The two air guide muffles 65 are provided with inlets and outlets on the sides facing the common channel 622, and the two lifting air guide doors 66 are respectively arranged at the inlets and outlets of the two air guide muffles 65. The two heat exchange mechanisms 67 are respectively arranged at the two sides of the air guide muffles 65 in the left cooling chamber 621 and the right cooling chamber 623. The two protective atmosphere supply pipelines are respectively arranged at the top outer side of the left cooling chamber 621 and the right cooling chamber 623 and communicate with the inside of the left cooling chamber 621 and the right cooling chamber 623. The protective atmosphere supply pipeline is connected to the protective atmosphere main pipeline (not shown) of the annular furnace heat treatment production line. The exhaust gas discharge pipeline is arranged at the top outer side of the common channel near the entrance of the intermediate cooling chamber and communicates with the inside of the common channel. The push-pull head of the push-pull mechanism 63 is used to pull the workpiece A placed on the common channel guide rail 624 into the left cooling chamber 621 or the right cooling chamber 623 to perform intermediate cooling treatment on the workpiece A, and then the push-pull head is used to push the workpiece A back to the common channel guide rail 624 to complete the intermediate cooling treatment of the workpiece A. The push-pull mechanism 63 can push or pull the material tray, which is generally similar to the structure of the guide chain pusher, and its special feature is the structure of the push-pull head, combined with the Figure 4a and 4bThe following are two push-pull head structures commonly used in current workpiece heat treatment equipment: Figure 4a The structure of the push-pull head 631 for the push-pull operation at the bottom of the tray B is shown. Figure 4b The structure shown is a push-pull material head 631 for the push-pull operation on the edge of the material tray B. Since the push-pull material mechanism 63 is a prior art, it will not be described in detail.

[0021] Furthermore, the heat exchange mechanism 67 is mainly composed of two groups of heat exchange coils (not shown in the figure), two groups of heat exchange fins (not shown in the figure) and a heat exchange medium driving device (not shown in the figure). The two groups of heat exchange coils are respectively fixedly arranged in the space between the two sides of the air guide muffle 65 and the two side walls of the intermediate cooling chamber lining 612, and the medium inlet end and the medium outlet end of the heat exchange coil both pass through the top of the double-station intermediate cooling chamber 6, the two groups of heat exchange fins are respectively installed on the two groups of heat exchange coils, and the heat exchange medium driving device is arranged on the outside of the double-station intermediate cooling chamber 6. When the heat exchange medium is outside air, the heat exchange medium driving device is an exhaust fan, and the medium outlet end is connected to the suction end of the exhaust fan, and the medium inlet end is connected to the outside environment. When the heat exchange medium is cooling oil, the heat exchange medium driving device is composed of an oil replenishing tank (not shown in the figure) and a circulating oil pump (not shown in the figure) connected to each other, the medium inlet end is connected to the pump outlet end of the circulating oil pump, and the medium outlet end is connected to the oil replenishing tank.

[0022] In a specific embodiment of the present invention, the rotary bottom type secondary heating furnace 7 is mainly composed of a secondary heating furnace shell 711, a secondary heating furnace lining 712, a circular rotary bottom 72, a plurality of tray brackets 73, a rotary bottom driving device (not shown), a plurality of radiation heating tubes 74, a plurality of high temperature fans 75, a protective atmosphere gas supply pipeline (not shown), an exhaust gas discharge pipeline (not shown), an observation window 76 and an inspection door 77. The secondary heating furnace shell 711 is covered on the outside of the secondary heating furnace lining 712 to form a furnace body structure of the rotary bottom type secondary heating furnace 7, and the interior of the secondary heating furnace lining 712 forms a circular furnace cavity. The two opposite sides of the furnace body structure of the rotary bottom type secondary heating furnace 7 are respectively provided with a secondary heating inlet and a secondary heating outlet that are connected to the circular furnace cavity. A circular rotary bottom 72 is installed at the bottom of the circular furnace cavity, and the plurality of tray brackets 73 are arranged at intervals and evenly on the upper side of the circular rotary bottom 72. The rotary bottom driving device is arranged below the circular rotary bottom 72 and is drivingly connected to the circular rotary bottom 72 to drive the circular rotary bottom 72 to rotate in the circumferential direction. The multiple radiation heating tubes 74 are evenly arranged in a circle in the circular furnace cavity. The multiple high-temperature fans 75 are evenly arranged in a circle on the upper part of the circular furnace cavity. The protective atmosphere gas supply pipeline is arranged on the top outer side of the circular furnace cavity and communicates with the inside of the circular furnace cavity. The protective atmosphere gas supply pipeline is connected to the protective atmosphere main pipeline of the annular furnace heat treatment production line. The exhaust gas discharge pipeline is arranged on the top outer side of the circular furnace cavity near the secondary heating inlet and communicates with the inside of the circular furnace cavity. The observation window 76 and the inspection door 77 are both arranged on the furnace body structure of the rotary bottom secondary heating furnace 7 and communicate with the inside of the circular furnace cavity.

[0023] Combination Figure 5 As shown, in a specific embodiment of the present invention, the heating furnace 3 is composed of a bottom charging section 31 and a sealed heating section 32, the height of the discharge port of the pre-oxidation furnace 2 is lower than the height of the bottom charging section 31, the bottom of the bottom charging section 31 is provided with a bottom charging port 311 and is surrounded by a fire curtain (not shown), and the lifting and loading mechanism 33 is arranged below the bottom charging port 311 and aligned with the discharge port of the pre-oxidation furnace 2. The workpiece after pre-oxidation treatment is moved to the lifting and loading mechanism 33 through the discharge port of the pre-oxidation furnace 2, and then the lifting and loading mechanism 33 lifts the workpiece and moves it into the bottom charging section 31 through the bottom charging port 311, and then moves the workpiece into the sealed heating section 32 for heating treatment. The bottom charging structure and the setting of the fire curtain of the heating furnace 3 can effectively prevent the entry of external air during the feeding stage, thereby preventing the occurrence of safety risks such as deflagration and explosion.

[0024] In a specific embodiment of the present invention, the feed port and the discharge port of the pre-oxidation furnace 2 are both equipped with a lifting furnace door 13, and a sealed lifting furnace door 14 is installed between the bottom loading section 31 and the sealed heating section 32, between the discharge port and the heating feed port of the heating furnace 3, between the feed port and the carburizing feed port, between the diffusion discharge port and the intermediate cooling chamber entrance, between the intermediate cooling chamber outlet and the secondary heating feed port, and between the secondary heating discharge port and the feed port of the quenching oil tank 8, thereby ensuring the heating and heat preservation operation of the pre-oxidation furnace 2, and ensuring the safe operation of the process of the heating furnace 3, the push-plate diffusion furnace 4, the annular carburizing furnace 5, the double-station intermediate cooling chamber 6 and the rotary bottom secondary heating furnace 7 under a protective atmosphere environment.

[0025] In a specific embodiment of the present invention, a guide rod pushing device 15 composed of a pressure-driven cylinder and a push rod is installed on one end of the loading platform 1 relative to the feed port of the pre-oxidation furnace 2, the outer side of the furnace wall of the pre-oxidation furnace 2 relative to its discharge port, the outer side of the furnace wall of the bottom loading section 31 relative to the sealed heating section 32, and the outer side of the furnace wall at the feed end of the push-plate diffusion furnace 4. The discharge device installed on the outer side of the furnace wall of the heating furnace 3 relative to its discharge port and the discharge mechanism of the diffusion furnace are both guide chain pushing devices 16 composed of a winding chain track, a chain, a push head, a driving motor and a sprocket. A workpiece supporting device 17 is installed on the outer side of the inner ring side furnace wall of the annular carburizing furnace 5 relative to its feed port and on the outer side of the quenching oil tank 8 relative to its feed port. The guide rod pushing device 15 and the guide chain pushing device 16 are both commonly used pushing devices in workpiece heat treatment equipment and will not be described in detail here. Figure 6As shown, the workpiece supporting device 17 is mainly composed of a supporting mechanism housing 171, a push drive motor 173, a screw 174, a material fork seat 175, a material fork 176, a plurality of supporting connecting rods 177, a lifting drive motor 178 and an eccentric cam 179, wherein the supporting mechanism housing 171 is a sealed housing and has an open port 172 at one end for being installed on the outer side of the inner ring side furnace wall of the annular carburizing furnace or the outer side of the quenching oil tank, the push drive motor 173 is fixedly installed on the outer side of the supporting mechanism housing 171 away from the open port 172, and the output end of the push drive motor 173 is driven and connected to one end of the screw 174 fixed in the supporting mechanism housing 171 through a reducer, and the material fork seat 175 has a screw hole and is screwed correspondingly to the screw 174 through the screw hole to fix the material fork seat 171. 75 is arranged on the screw rod 174, and the two sides of the material fork seat 175 are embedded in the slideways on both sides of the supporting mechanism shell 171, the material fork 176 is located above the material fork seat 175 and is pivotally connected to the material fork 176 and the material fork seat 175 through the two ends of several supporting connecting rods 177, so that the material fork 176 is movably connected with the material fork seat 175, the lifting drive motor 178 is installed on the supporting mechanism shell 171 and the output end thereof is driven and connected with the eccentric cam 179 installed inside the supporting mechanism shell 171 through a chain, the material fork 176 is placed flat on the cam portion of the eccentric cam 179, and the screw rod 174 is driven to rotate by the pushing drive motor 173 and the eccentric cam 179 is driven to rotate by the lifting drive motor 178, so as to push or withdraw the material fork 176 and lift or put it down.

[0026] In a specific embodiment of the present invention, Figure 7 As shown, the quenching oil tank 8 has a sealed front chamber 81, a discharge chamber 82, a quenching oil pool 83 and a workpiece quenching moving mechanism 84. A feed port is provided on one side of the sealed front chamber 81, and a workpiece supporting device 17 is installed on the outer side of the other side. A discharge port is provided on one side of the discharge chamber 82. The sealed front chamber 81 and the discharge chamber 82 are arranged side by side above the quenching oil pool 83, and the lower parts of the sealed front chamber 81 and the discharge chamber 82 are communicated with the quenching oil pool 83. The quenching oil pool 83 contains quenching oil. The sealed front chamber 81 is sealed and isolated from the discharge chamber 82 by the quenching oil in the quenching oil pool 83, and the workpiece quenching moving mechanism 84 is arranged in the sealed front chamber 81, the discharge chamber 82 and the quenching oil pool 83 to move the workpiece and perform quenching operations.

[0027] In a specific embodiment of the present invention, the cleaning machine 9 can be composed of an alkaline water soaking position, a clean water spraying position and a drying position arranged in sequence, thereby being able to thoroughly clean the workpiece after quenching.

[0028] In addition, as another specific embodiment of the present invention, the annular furnace heat treatment production line may also include a tempering furnace 11 and an air cooling table 12, and the tempering furnace 11 and the air cooling table 12 are sequentially connected between the cleaning machine 9 and the discharge table 10, thereby enabling the annular furnace heat treatment production line to have tempering and air cooling process links.

[0029] In addition, in the above two specific embodiments of the present invention, the annular furnace heat treatment production line may also include a central control unit (not shown in the figure), which is electrically connected to the driving control unit of the lifting furnace door, the sealed lifting furnace door, the guide rod pushing device, the guide chain pushing device, the workpiece supporting device, the heat exchange mechanism, the bottom rotating drive device, the radiation heating tube, the high-temperature fan, the protective atmosphere gas supply pipeline, the exhaust gas discharge pipeline and other components in the above equipment, as well as the sensor components such as the thermocouple, the atmosphere sensor, the temperature sensor, and the pressure sensor, so as to control the automatic operation of the annular furnace heat treatment production line through the set instructions. The central control unit can be composed of a programmable logic control circuit (PLC), or a centralized control circuit, or a central control host computer or a server, etc., and in view of the current application of programmable logic control circuits, centralized control circuits, central control host computers or servers, etc., according to relevant instructions and sensor detection data, etc., the operation status of each component has long been widely used and commonly used in the field of automatic control, that is, the existing control technology, so the application of the central control unit in the present invention to control the operation process of the above components will not be repeated. Through the centralized control of the central control unit, the ring furnace heat treatment production line can be fully automated, thus saving labor costs.

[0030] In summary, the present invention sequentially adds a double-station intermediate cooling chamber and a rotary bottom secondary heating furnace between the push-plate diffusion furnace and the quenching oil tank of the annular furnace heat treatment production line, and enables the diffusion furnace discharge mechanism of the push-plate diffusion furnace to selectively push the workpiece to the common channel or directly push it to the rotary bottom secondary heating furnace according to the heat treatment requirements of different types of workpieces, so as to selectively implement intermediate cooling, secondary heating and quenching treatment on the workpiece after diffusion treatment or directly implement quenching treatment. In addition, since the double-station intermediate cooling chamber has two left and right cooling chambers, it can perform intermediate cooling operations on two workpieces at the same time, and the rotary bottom secondary heating furnace can also perform secondary heating operations on multiple workpieces at the same time, thereby enabling the annular furnace heat treatment production line to have continuous heat treatment capabilities like an assembly line and large-scale workpiece processing capabilities, thereby having higher heat treatment efficiency.

[0031] The present invention also provides a process for heat treating a workpiece using the above-mentioned annular furnace heat treatment production line, the steps of the process comprising: Pre-oxidation step: the workpieces loaded in several trays are transferred to the pre-oxidation furnace through the loading platform for pre-oxidation treatment; Heating step: the workpiece after pre-oxidation treatment is transferred to the heating furnace through the lifting and loading mechanism for heating treatment in a protective atmosphere environment; Carburizing step: the workpiece after heating is transferred to the annular carburizing furnace for carburizing treatment in a protective atmosphere; Diffusion step: the carburized workpiece is transferred to a push-plate diffusion furnace for diffusion treatment in a protective atmosphere; Process selection steps: when it is necessary to perform intermediate cooling and secondary heating treatment on the workpiece after diffusion treatment, the diffusion furnace discharge mechanism of the push-plate diffusion furnace pushes the workpiece to the common channel of the double-station intermediate cooling chamber, the workpiece is moved into the left cooling chamber or the right cooling chamber and performs intermediate cooling treatment under a protective atmosphere, the workpiece after intermediate cooling treatment is moved back to the common channel, and then the diffusion furnace discharge mechanism pushes the workpiece to the rotary bottom secondary heating furnace for secondary heating treatment under a protective atmosphere; or when it is necessary to directly perform quenching treatment on the workpiece after diffusion treatment, the diffusion furnace discharge mechanism pushes the workpiece directly to the rotary bottom secondary heating furnace for transfer; Quenching step: the workpiece after secondary heating treatment or diffusion treatment is transferred to the quenching oil tank for quenching treatment; Cleaning step: the workpiece after quenching is transferred to the cleaning machine for cleaning; Discharging step: The workpiece after cleaning is transferred to the discharging platform for discharging.

[0032] Accordingly, the above process can simultaneously meet the different heat treatment requirements of ordinary workpieces and special metal workpieces, and can ensure the orderly and coherent implementation of each step in the process, thereby saving manpower and material investment costs and improving the heat treatment efficiency of the workpiece.

[0033] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Other equivalent changes made using the patent concept of the present invention should all fall within the patent protection scope of the present invention.

Claims

1. A ring furnace heat treatment production line with intermediate cooling and secondary heating functions, used for selectively performing carburizing, intermediate cooling, secondary heating and quenching operations or performing carburizing and quenching operations on workpieces loaded in a tray, the ring furnace heat treatment production line comprising: A loading platform, a pre-oxidation furnace, a heating furnace, a push-plate diffusion furnace, an annular carburizing furnace, a quenching oil tank, a cleaning machine and a discharging platform, wherein the loading platform is connected to the feeding port of the pre-oxidation furnace, the discharging port of the pre-oxidation furnace is connected to the bottom charging section of the heating furnace through a lifting and loading mechanism, and a heating feeding port and a carburizing feeding port which are aligned with each other are respectively provided on two opposite side walls of the feeding end of the push-plate diffusion furnace, the discharging port of the heating furnace is sealedly connected to the heating feeding port, and the feeding and discharging port of the annular carburizing furnace is sealedly connected to the carburizing feeding port. The invention is characterized in that the annular furnace heat treatment production line further comprises: a double-station intermediate cooling chamber and a rotary bottom secondary heating furnace, the interior of the double-station intermediate cooling chamber is divided into a left cooling chamber, a common channel and a right cooling chamber in sequence from one side to the other side, and an intermediate cooling chamber inlet and an intermediate cooling chamber outlet communicating with the common channel are respectively provided on two opposite side walls of the double-station intermediate cooling chamber adjacent to both ends of the common channel, a diffusion discharge port is provided on one side wall of the discharge end of the push-disk diffusion furnace, the intermediate cooling chamber inlet is sealedly connected to the diffusion discharge port, and the The secondary heating inlet of the rotary bottom secondary heating furnace is sealed and connected with the outlet of the intermediate cooling chamber, the secondary heating outlet of the rotary bottom secondary heating furnace is sealed and connected with the inlet of the quenching oil tank, the outlet of the quenching oil tank is connected with the inlet of the cleaning machine, and the outlet of the cleaning machine is connected with the discharging platform; the diffusion furnace discharging mechanism of the push-plate diffusion furnace can selectively push the workpiece after carburizing diffusion treatment to the common channel or directly push it into the rotary bottom secondary heating furnace, wherein when the workpiece is When the furnace discharge mechanism pushes the workpiece onto the common channel, the workpiece is moved into the left cooling chamber or the right cooling chamber for intermediate cooling treatment, and then the diffusion furnace discharge mechanism pushes the workpiece after the intermediate cooling treatment into the rotary bottom secondary heating furnace for secondary heating treatment, and then the workpiece after the secondary heating treatment is sent to the quenching oil tank for quenching treatment. When the workpiece is directly pushed into the rotary bottom secondary heating furnace by the diffusion furnace discharge mechanism, the workpiece is sent into the quenching oil tank for quenching treatment through the rotary bottom secondary heating furnace.

2. The annular furnace heat treatment production line according to claim 1 is characterized in that: The double-station intercooling chamber is mainly composed of an intercooling chamber shell, an intercooling chamber lining, a pair of common channel guide rails, two pairs of intercooling chamber guide rails, two push-pull material mechanisms, two high-temperature fans, two air guide muffles, two lifting air guide doors, two heat exchange mechanisms, two protective atmosphere air supply pipelines and exhaust gas exhaust pipelines. The intercooling chamber shell is coated on the outside of the intercooling chamber lining, and the interior of the intercooling chamber lining is divided into the left cooling chamber, the common channel and the right cooling chamber in sequence from one side to the other. The two opposite sides of the intercooling chamber shell and the intercooling chamber lining are respectively provided with The intermediate cooling chamber entrance and the intermediate cooling chamber exit communicated with the common passage, the pair of common passage guide rails are fixedly laid on the bottom of the common passage along the direction from the intermediate cooling chamber entrance to the intermediate cooling chamber exit, the two pairs of intermediate cooling chamber guide rails are perpendicular to the pair of common passage guide rails and are respectively fixedly laid on the bottom of the left cooling chamber and the right cooling chamber, the two push-pull material mechanisms are respectively fixedly installed on the outside of the other two opposite side walls perpendicular to the side wall with the intermediate cooling chamber entrance, and the other two opposite side walls correspond to the two push-pull material mechanisms The positions of the push-pull material heads of the structure are respectively provided with material head openings for the push-pull material heads to enter and exit, the two high-temperature fans are respectively installed on the tops of the left cooling chamber and the right cooling chamber, the two air guide muffles are respectively covered on the middle cooling chamber guide rails of the left cooling chamber and the right cooling chamber and are in communication with the high-temperature fans, the two air guide muffles are respectively provided with inlets and outlets on the sides facing the common passage, the two lifting air guide doors are respectively provided at the inlets and outlets of the two air guide muffles, the two heat exchange mechanisms are respectively provided on the air guide muffles in the left cooling chamber and the right cooling chamber On both sides of the left cooling chamber, the two protective atmosphere supply pipelines are respectively arranged on the top outer side of the left cooling chamber and the right cooling chamber and communicated with the left cooling chamber and the right cooling chamber, the exhaust gas discharge pipeline is arranged on the top outer side of the common channel adjacent to the entrance of the intermediate cooling chamber and communicated with the common channel, the workpiece placed on the common channel guide rail is pulled into the left cooling chamber or the right cooling chamber by the pushing and pulling head of the pushing and pulling material mechanism to perform intermediate cooling treatment on the workpiece, and then the workpiece is pushed back to the common channel guide rail by the pushing and pulling head to complete the intermediate cooling treatment of the workpiece.

3. The annular furnace heat treatment production line according to claim 2 is characterized in that: The heat exchange mechanism is mainly composed of two groups of heat exchange coils, two groups of heat exchange fins and a heat exchange medium driving device, the two groups of heat exchange coils are respectively fixedly arranged in the space between the two sides of the air guide muffle and the two side walls of the intermediate cooling chamber lining, and the medium inlet end and the medium outlet end of the heat exchange coil both pass through the top of the double-station intermediate cooling chamber, the two groups of heat exchange fins are respectively installed on the two groups of heat exchange coils, and the heat exchange medium driving device is arranged on the outside of the double-station intermediate cooling chamber. When the heat exchange medium is outside air, the heat exchange medium driving device is an exhaust fan, and the medium outlet end is connected to the suction end of the exhaust fan, and the medium inlet end is connected to the external environment; when the heat exchange medium is cooling oil, the heat exchange medium driving device is composed of a replenishing oil tank and a circulating oil pump connected to each other, the medium inlet end is connected to the pump outlet end of the circulating oil pump, and the medium outlet end is connected to the replenishing oil tank.

4. The annular furnace heat treatment production line according to claim 1 is characterized in that: The rotary bottom secondary heating furnace is mainly composed of a secondary heating furnace shell, a secondary heating furnace lining, a circular rotary bottom, a plurality of material tray brackets, a rotary bottom driving device, a plurality of radiation heating tubes, a plurality of high-temperature fans, a protective atmosphere gas supply pipeline, an exhaust gas exhaust pipeline, an observation window and an inspection door. The secondary heating furnace shell is covered on the outside of the secondary heating furnace lining, and a circular furnace cavity is formed inside the secondary heating furnace lining. The secondary heating inlet and the secondary heating outlet communicated with the circular furnace cavity are respectively provided on two opposite sides of the secondary heating furnace shell and the secondary heating furnace lining. The circular rotary bottom is installed at the bottom of the circular furnace cavity, and the upper side surface of the circular rotary bottom is spaced and evenly The multiple material tray brackets are arranged in a circular manner, the rotary bottom driving device is arranged below the circular rotary bottom and is connected to the circular rotary bottom drive to drive the circular rotary bottom to rotate in a circumferential direction, the multiple radiation heating tubes are evenly arranged in a circle in the circular furnace cavity, the multiple high-temperature fans are evenly arranged in a circle on the upper part of the circular furnace cavity, the protective atmosphere supply pipeline is arranged on the top outer side of the circular furnace cavity and communicates with the circular furnace cavity, the exhaust gas discharge pipeline is arranged on the top outer side of the circular furnace cavity adjacent to the secondary heating material inlet and communicates with the circular furnace cavity, the observation window and the inspection door are both arranged on the secondary heating furnace shell and the secondary heating furnace lining and communicate with the circular furnace cavity.

5. The annular furnace heat treatment production line according to claim 1 is characterized in that: The heating furnace is composed of a bottom loading section and a sealed heating section which are sealed and connected. The height of the discharge port of the pre-oxidation furnace is lower than the height of the bottom loading section. A bottom loading port is provided at the bottom of the bottom loading section and is surrounded by a fire curtain. The lifting and loading mechanism is provided below the bottom loading port and aligned with the discharge port of the pre-oxidation furnace. The workpiece after pre-oxidation treatment is moved to the lifting and loading mechanism through the discharge port of the pre-oxidation furnace, and the lifting and loading mechanism lifts the workpiece and moves it to the bottom loading section through the bottom loading port and then to the sealed heating section for heating treatment.

6. The annular furnace heat treatment production line according to claim 5, characterized in that: The feed inlet and discharge port of the pre-oxidation furnace are both equipped with lifting furnace doors, and sealed lifting furnace doors are all installed between the bottom loading section and the sealed heating section, between the discharge port of the heating furnace and the heating feed inlet, between the feed inlet and the carburizing feed inlet, between the diffusion discharge port and the intermediate cooling chamber entrance, between the intermediate cooling chamber outlet and the secondary heating feed inlet, and between the secondary heating discharge port and the feed inlet of the quenching oil tank.

7. The annular furnace heat treatment production line according to claim 6, characterized in that: A guide rod pushing device consisting of a pressure-driven cylinder and a push rod is installed on one end of the loading platform opposite to the feed port of the pre-oxidation furnace, the outer side of the furnace wall of the pre-oxidation furnace opposite to its discharge port, the outer side of the furnace wall of the bottom loading section opposite to the sealed heating section, and the outer side of the furnace wall at the feed end of the push-plate diffusion furnace. The discharge device installed on the outer side of the furnace wall of the heating furnace opposite to its discharge port and the discharge mechanism of the diffusion furnace are both guide chain pushing devices consisting of a winding chain track, a chain, a push head, a driving motor and a sprocket. A workpiece supporting device is installed on the outer side of the inner ring side furnace wall of the annular carburizing furnace opposite to its feed port and on the outer side of the quenching oil tank opposite to its feed port.

8. The annular furnace heat treatment production line according to claim 1, characterized in that: Also includes: A tempering furnace and an air cooling table are connected in sequence between the cleaning machine and the discharging table.

9. The annular furnace heat treatment production line according to claim 1, characterized in that: The cleaning machine is composed of an alkaline water soaking position, a clean water spraying position and a drying position which are arranged in sequence.

10. A process for heat treatment of workpieces using the annular furnace heat treatment production line with intermediate cooling and secondary heating functions as claimed in claim 1, characterized in that the steps include: Pre-oxidation step: the workpieces loaded in several trays are transferred to the pre-oxidation furnace through the loading platform for pre-oxidation treatment; Heating step: the workpiece after pre-oxidation treatment is transferred to the heating furnace through the lifting and loading mechanism for heating treatment in a protective atmosphere environment; Carburizing step: the workpiece after heating is transferred to the annular carburizing furnace for carburizing treatment in a protective atmosphere; Diffusion step: the carburized workpiece is transferred to a push-plate diffusion furnace for diffusion treatment in a protective atmosphere; Process selection steps: when it is necessary to perform intermediate cooling and secondary heating treatment on the workpiece after diffusion treatment, the diffusion furnace discharge mechanism of the push-plate diffusion furnace pushes the workpiece to the common channel of the double-station intermediate cooling chamber, the workpiece is moved into the left cooling chamber or the right cooling chamber and performs intermediate cooling treatment under a protective atmosphere, the workpiece after intermediate cooling treatment is moved back to the common channel, and then the diffusion furnace discharge mechanism pushes the workpiece to the rotary bottom secondary heating furnace for secondary heating treatment under a protective atmosphere; or when it is necessary to directly perform quenching treatment on the workpiece after diffusion treatment, the diffusion furnace discharge mechanism pushes the workpiece directly to the rotary bottom secondary heating furnace for transfer; Quenching step: the workpiece after secondary heating treatment or diffusion treatment is transferred to the quenching oil tank for quenching treatment; Cleaning step: the workpiece after quenching is transferred to the cleaning machine for cleaning; Discharging step: The workpiece after cleaning is transferred to the discharging platform for discharging.

Images