Workpiece carburizing production line with quenching and slow cooling functions and workpiece heat treatment method

Abstract

A workpiece carburizing production line and a workpiece heat treatment method with both quenching and slow cooling functions, wherein the workpiece carburizing production line includes a push-plate carburizing furnace, a quenching chamber and a push-plate slow cooling furnace which are sealed and connected in sequence, and the carburizing furnace discharge mechanism can selectively push the workpiece after carburizing treatment to the sealed front chamber of the quenching chamber or to the push-plate slow cooling furnace through the sealed front chamber, so that the workpiece quenching moving mechanism drives the workpiece from the sealed front chamber to the quenching tank for quenching operation, and then outputs the workpiece through the discharge chamber, or the guide chain moving mechanism drives several workpieces in a step-by-step manner in the slow cooling space of the push-plate slow cooling furnace for slow cooling operation, and then the slow cooling furnace discharge mechanism pushes the workpiece after slow cooling into the slow cooling discharge ventilation chamber to output the workpiece; the above-mentioned quenching or slow cooling operations are all performed in an environment where air is isolated and the carburizing atmosphere is controlled, which can not only realize the selective operation of the quenching or slow cooling process of the workpiece after carburizing, but also realize large-scale continuous production of the slow cooling process.

Description

Technical Field

[0001] The present invention relates to the technical field of workpiece heat treatment, and in particular to a workpiece carburizing production line and a workpiece heat treatment method having both quenching and slow cooling functions. Background Art

[0002] At present, the carburizing and subsequent slow cooling process of the workpiece heat treatment is usually achieved by directly connecting a cycle furnace to a single-chamber slow cooling chamber. The process is to first use a cycle furnace to carburize the workpiece in a protective atmosphere, and then the workpiece enters the single-chamber slow cooling chamber for slow cooling. The advantage of the single-chamber slow cooling chamber is that the slow cooling chamber has a small space size. Even if a small amount of air enters, it will be directly ignited by the open flame of the high-temperature workpiece and the incoming combustible atmosphere, and generally no explosion will occur. However, the single-chamber slow cooling chamber can only perform slow cooling operations on one workpiece at a time, and the slow cooling process cycle is long, resulting in very low overall production efficiency of carburizing and slow cooling of the workpiece, and it is impossible to achieve mass production of workpieces. In addition, as users' demands for workpiece heat treatment processes are becoming more and more diverse, some users require that the workpiece must be quenched immediately after the carburizing process. Therefore, in order to meet the diverse needs of users and to ensure the safe implementation of the process and the process quality (air must be prevented from entering during the slow cooling or quenching process), usually two production lines are required to achieve the carburizing and slow cooling or quenching processes of the workpiece. One of the production lines is a periodic furnace directly connected to a single-chamber slow cooling chamber to achieve the carburizing and slow cooling processes of the workpiece, and the other production line is a periodic furnace directly connected to a quenching chamber to achieve the carburizing and quenching processes of the workpiece. As a result, the cost investment in production equipment remains high, and the production equipment occupies a large production site. In addition, the above-mentioned production lines cannot achieve mass production of workpieces, which makes the production efficiency of the production line very low.

[0003] Therefore, how to develop a heat treatment production line with relatively low equipment cost investment, which can save production land and realize large-scale production of workpiece carburizing and subsequent processes has become one of the technical problems to be solved urgently in this field. Summary of the invention

[0004] The technical problem to be solved by this technical solution is how to make the workpiece heat treatment carburizing production line simultaneously meet the subsequent process requirements of quenching and slow cooling, and enable the entire production line to achieve mass production of workpieces.

[0005] In order to solve the above technical problems, the present technical scheme provides a workpiece carburizing production line with both quenching and slow cooling functions, the workpiece carburizing production line includes a push-plate carburizing furnace, a quenching chamber and a push-plate slow cooling furnace; wherein, the carburizing furnace discharge port of the push-plate carburizing furnace is connected to one side of the sealed front chamber of the quenching chamber, and the carburizing furnace discharge port is equipped with a sealed furnace door, and a carburizing furnace discharge mechanism is arranged on the side wall of the push-plate carburizing furnace opposite to the carburizing furnace discharge port; the quenching chamber includes a sealed front chamber, a discharge chamber, a quenching tank and a workpiece quenching moving mechanism, the sealed front chamber and the discharge chamber are located above the quenching tank and The lower part is connected with the quenching tank, and the workpiece quenching moving mechanism is arranged in the sealed front chamber, the discharge chamber and the quenching tank; the push-plate type slow cooling furnace includes a furnace body, a guide chain moving mechanism, a gas circulation mechanism, a heat preservation mechanism, a cooling mechanism, a slow cooling discharge ventilation chamber, an exhaust gas discharge mechanism, a protective gas intake mechanism and a slow cooling furnace discharge mechanism. A slow cooling space is formed inside the furnace body, and a slow cooling feed port and a slow cooling discharge port which are connected with the slow cooling space and have sealed furnace doors are respectively arranged on the side walls at both ends of the furnace body. The guide chain moving mechanism and the gas circulation mechanism are both arranged in the furnace body and are respectively located at the bottom and top of the slow cooling space. The heat preservation mechanism and the cooling mechanism are both arranged in the furnace body and are respectively located in a section of the slow cooling space adjacent to the slow cooling feed port and a section adjacent to the slow cooling discharge port. The slow cooling discharge ventilation chamber is arranged outside the slow cooling discharge port. The waste gas discharge mechanism and the protective gas intake mechanism are respectively arranged on the side wall of the furnace body adjacent to the slow cooling feed port and the top of the slow cooling discharge ventilation chamber and on the side wall of the furnace body adjacent to the slow cooling discharge port and the lower part of the slow cooling discharge ventilation chamber and are respectively communicated with the slow cooling space and the inside of the slow cooling discharge ventilation chamber. The slow cooling furnace discharge mechanism is arranged on the side wall of the furnace body opposite to the slow cooling discharge port. The slow cooling of the furnace body The feed port is connected to the other side of the sealed front chamber of the quenching chamber; the carburizing furnace discharging mechanism can selectively push the workpieces processed by the push-plate carburizing furnace to the workpiece quenching moving mechanism in the sealed front chamber or the guide chain moving mechanism in the push-plate slow cooling furnace, so that the workpiece quenching moving mechanism drives the workpiece from the sealed front chamber to the quenching tank for quenching operation, and then outputs the workpiece through the discharging chamber, or the guide chain moving mechanism drives several workpieces in a step-by-step manner in the slow cooling space for slow cooling operation, and then the slow cooling furnace discharging mechanism pushes the slow-cooled workpiece into the slow cooling discharging ventilation chamber to output the workpiece.Accordingly, the workpiece carburizing production line of the present technical solution seals and connects the push-plate carburizing furnace, quenching chamber and push-plate slow cooling furnace in sequence according to the workpiece heat treatment process flow, and uses the sealed front chamber of the quenching chamber as a "transfer platform". The workpiece carburized by the push-plate carburizing furnace can be pushed to the sealed front chamber by the carburizing furnace discharge mechanism to implement the quenching process, and can also be pushed to the slow cooling space of the push-plate slow cooling furnace through the sealed front chamber by the carburizing furnace discharge mechanism to implement the slow cooling process. This selective operation can enable the workpiece carburizing production line to meet multiple process steps at the same time, thereby reducing the cost of production equipment investment and saving production land use; and the push-plate slow cooling furnace can simultaneously meet the slow cooling operations of several workpieces in the slow cooling space, and the closely adjacent conveying structure of several workpieces can also reduce the volume of the enclosed space in the slow cooling space, thereby not only realizing mass production of workpieces and improving the production efficiency of the workpiece carburizing production line, but also reducing the risk of explosion. In addition, before the quenching process and during the slow cooling process, the workpiece is required not to be oxidized at high temperature, and in the process of transferring the workpiece to the sealed front chamber or slow cooling space, the carburizing atmosphere in the push-plate carburizing furnace will inevitably enter the quenching chamber and the push-plate slow cooling furnace. Since the carburizing atmosphere contains a large amount of hydrogen and carbon monoxide atmosphere, and during the implementation of the slow cooling process, the temperature in the push-plate slow cooling furnace will drop from about 900°C to about 100°C, which will gradually fall below the explosion safety temperature of 750°C. Moreover, since the push-plate slow cooling furnace has to carry out slow cooling operations on multiple workpieces at the same time, the size of the enclosed space is large, and sparks will inevitably be generated during the transfer of the workpiece. Therefore, in order to prevent the carburized workpiece from being oxidized in the subsequent process, and to prevent the explosion hazard caused by a small amount of air entering the push-plate slow cooling furnace, the quenching chamber of the present technical solution arranges the sealed front chamber and the discharge chamber on the upper part of the quenching tank and physically isolates the sealed front chamber and the discharge chamber with the quenching medium to effectively prevent air from entering through the quenching chamber. The workpiece carburizing production line; and the slow cooling discharge ventilation chamber arranged outside the slow cooling discharge port of the push-plate type slow cooling furnace can also effectively prevent air from entering the workpiece carburizing production line through the discharge end of the push-plate type slow cooling furnace; furthermore, the exhaust gas discharge mechanism and the protective gas intake mechanism are respectively arranged on the side wall of the furnace body near the slow cooling feed port and the slow cooling discharge port, which can make the protective gas (usually nitrogen) flow from the slow cooling discharge port to the slow cooling feed port, that is, from the low temperature section to the high temperature section (the low temperature section has a temperature lower than the explosion safety temperature of 750 °C and there is a great risk of explosion), thereby effectively avoiding the risk of explosion in the push-plate type slow cooling furnace, and maintaining the furnace pressure in the push-plate type slow cooling furnace, and because the concentration of the carburizing atmosphere at the slow cooling feed inlet is relatively high, the protective gas can also dilute the carburizing atmosphere, and the exhaust gas discharge mechanism arranged at the slow cooling feed inlet is more conducive to removing the carburizing atmosphere and maintaining the stability of the furnace pressure, and preventing the carburizing atmosphere from diffusing and crosstalking into the slow cooling space to the greatest extent, thereby effectively improving the operation safety of the workpiece carburizing production line.

[0006] As another implementation of the present technical solution, the workpiece quenching moving mechanism includes a quenching elevator, a quenching lifting platform, a transfer platform, a transfer push chain, a discharging elevator and a discharging lifting platform; wherein the quenching elevator is installed on the outer side surface of the top wall of the sealed front chamber and its lifting drive end vertically downwardly penetrates the top wall of the sealed front chamber and is located in the sealed front chamber; the quenching lifting platform can be moved up and down in the sealed front chamber and the quenching lifting platform is composed of a quenching platform and a frame surrounded by the upper part of the quenching platform. In the initial state, the quenching platform is flush with the bottom of the sealed front chamber, and the lifting drive end of the quenching elevator is fixedly connected to the top of the frame of the quenching lifting platform; the transfer platform is horizontally arranged in the quenching tank and is provided with slots corresponding to the quenching lifting platform and the discharging lifting platform; the transfer push chain is composed of an L-shaped chain guide plate, a chain, a driving motor and a driving wheel. The L-shaped chain guide plate is installed on the outer side of the sealed front chamber and its vertical section is penetrated into the quenching tank so that its horizontal section is against the upper side of the transfer platform. The chain can be moved The lifting drive end of the discharging lift is vertically penetrated through the top wall of the discharging chamber and is located in the discharging chamber; the discharging lift platform can be moved up and down in the discharging chamber and the discharging lift platform is composed of a discharging platform and a frame body surrounded by the upper part of the discharging platform, and the lifting drive end of the discharging lift is fixedly connected to the top of the frame body of the discharging lift platform; the discharging mechanism of the carburizing furnace pushes the workpiece to the quenching platform, and the quenching lift platform is driven to descend to the slot corresponding to the transfer platform and make the quenching platform flush with the upper side of the transfer platform, and then the driving motor of the transfer push chain drives the chain to push the workpiece to the discharging platform of the discharging lift platform that descends to the slot corresponding to the transfer platform, and then the discharging lift platform is driven by the discharging lift platform to the discharging chamber to output the workpiece. Accordingly, the sealed front chamber and the discharge chamber can be physically isolated by the quenching medium, which can effectively prevent air from entering the sealed front chamber from the discharge end, and can also prevent the loss of quenching steam generated after the workpiece is quenched. Therefore, it can prevent the carburizing atmosphere and air from mixing and exploding, thereby improving the safety of the quenching chamber operation, and prevent the oxygen in the air from oxidizing the workpiece, thereby ensuring the quenching quality of the workpiece, and preventing the loss of quenching steam and reducing resource consumption.

[0007] As another implementation of the present technical solution, the quenching chamber also includes an air baffle, an isolation door lifting mechanism, an exhaust gas discharge port and a protective gas inlet; wherein, the air baffle is vertically arranged at the upper part of the quenching tank and is located between the sealed front chamber and the discharge chamber, and the lower end of the air baffle is inserted below the liquid level of the quenching medium in the quenching tank to isolate the area above the liquid level of the quenching medium in the quenching tank; the isolation door lifting mechanism includes an isolation door, a lifting motor and an isolation plate, the isolation door is vertically and movable up and down on the quenching tank between the sealed front chamber and the discharge chamber, the lifting motor is installed above the quenching tank and is located next to the isolation door and is connected to the isolation door drive, the isolation plate is vertically and corresponding to the position of the isolation door and is arranged below the transfer platform, the lifting motor can drive the isolation door to move downward and abut the transfer platform, so that the isolation door and the isolation plate separate the quenching tank into a quenching area and a discharge area; the exhaust gas discharge port and the protective gas inlet are both arranged in the sealed front chamber. Accordingly, the setting of the air baffle and the isolation door lifting mechanism can further prevent outside air from entering the sealed front chamber from the discharge chamber, and can prevent quenching steam from flowing from the sealed front chamber to the discharge chamber; and the setting of the exhaust gas discharge port and the protective gas inlet port can effectively reduce the impact of the carburizing atmosphere on subsequent processes.

[0008] As another implementation of the present technical solution, the push-plate carburizing furnace, quenching chamber and push-plate slow cooling furnace are all provided with two parallel guide rails connected to each other, so as to push and transfer the workpiece between the various devices of the workpiece carburizing production line, wherein the guide rails in the push-plate carburizing furnace are generally composed of silicon carbide guide rails or heat-resistant steel guide rails, while the guide rails in the quenching chamber and the push-plate slow cooling furnace are composed of heat-resistant steel guide rails; the guide chain moving mechanism is arranged between the two parallel guide rails at the bottom of the slow cooling space along the direction from the slow cooling feed inlet to the slow cooling discharge outlet, and the guide chain moving mechanism includes a C-shaped groove rail composed of several sections of groove rails assembled in sequence, several fixed grooves, guide rails Chain, pulling head and reciprocating drive motor, wherein each groove rail is composed of two channel steels with their groove openings facing each other and spaced apart, the C-shaped groove rail is arranged between two parallel guide rails at the bottom of the slow cooling space, the several fixed grooves correspond to the several sections of groove rails and are fixedly arranged on the inner side of the C-shaped groove rail at the same distance, and each groove rail is fixedly embedded in the groove opening of each fixed groove, the guide chain is movably embedded in the C-shaped groove rail, the pulling head is fixedly combined on the upper side surface of the guide chain adjacent to the slow cooling feed port and exposed on the upper side of the C-shaped groove rail, the reciprocating drive motor is installed at the bottom of the furnace body and its driving end is driven and connected with the guide chain through a sprocket engagement. The C-shaped groove rail and the fixed groove are used to support the guide chain, and the structural strength of the guide chain moving mechanism can be effectively strengthened, thereby improving the carrying capacity of the guide chain moving mechanism; and due to the height difference between the guide rail at the bottom of the slow cooling space and the guide chain moving mechanism, the workpiece pushed into the slow cooling space is placed on the guide rail, and the guide chain in the C-shaped groove rail is driven by the reciprocating drive motor to drive the pulling head to move back and forth, so that the workpiece fed through the slow cooling feed port can be pushed by the pulling head and push against the workpiece in front to move, so that several workpieces in the slow cooling space are moved one by one along the guide rail in a step-by-step manner toward the slow cooling discharge port. The conveying structure with several workpieces closely close to each other can effectively reduce the size of the empty and enclosed space in the slow cooling space, thereby effectively reducing the possibility of deflagration or explosion of the push-plate slow cooling furnace; in addition, the workpiece conveying mechanism in the furnace, which is mainly composed of the C-shaped groove rail, the guide chain and the reciprocating drive motor, can also effectively reduce the complexity of the mechanism and reduce the occupation of the bottom space of the push-plate slow cooling furnace.

[0009] As another implementation of the technical solution, the gas circulation mechanism is composed of several circulation fans, an air guide top plate and two air guide side plates, wherein the several circulation fans are arranged at the top of the slow cooling space at the same distance along the direction from the slow cooling feed inlet to the slow cooling outlet, the air guide top plate is provided with several fan holes corresponding to the several circulation fans, the air guide top plate is horizontally arranged at the top of the slow cooling space and the fan holes are correspondingly provided with circulation fans, the two air guide side plates are vertically arranged in the slow cooling space and are located on both sides of two parallel guide rails, and the upper side edges of the two air guide side plates are respectively fixedly combined with the side edges of the air guide top plate. The airflow generated by the circulation fan is guided by the air guide top plate and the air guide side plates, so that the airflow flows in an orderly and rapid manner in a fixed direction, so as to ensure uniform slow cooling of the workpiece, thereby improving the quality of the product.

[0010] As another implementation of the technical solution, the heat preservation mechanism is composed of several heating elements, which are arranged in a section of the slow cooling space adjacent to the slow cooling feed port and are respectively located between the two side walls of the furnace body and the two air guide side plates; and the cooling mechanism is composed of several serpentine tubes and several heat dissipation fins sleeved on the serpentine tubes, which are arranged in a section of the slow cooling space adjacent to the slow cooling discharge port and are respectively located between the two side walls of the furnace body and the two air guide side plates; the heat preservation mechanism and the cooling mechanism divide the slow cooling space into a heat preservation section and a cooling section. In this way, the workpiece performs the slow cooling operation according to the slow cooling process requirements during the movement in the slow cooling space.

[0011] As another implementation of the technical solution, the workpiece carburizing production line also includes two explosion-proof pressure relief devices, each of which is composed of a flange, an explosion-proof membrane, an insulation layer and a protective plate, wherein the explosion-proof membrane is arranged in the flange hole of the flange, the insulation layer is arranged at the bottom of the flange, and the protective plate is arranged at the top of the flange, and explosion-proof pressure relief ports are provided at the top of the furnace body and the top of the slow cooling and discharging ventilation chamber, and the two explosion-proof pressure relief devices are respectively fixedly mounted on the explosion-proof pressure relief ports of the furnace body and the slow cooling and discharging ventilation chamber with flanges. The explosion-proof pressure relief device can be used as a safety device for emergency pressure relief of the push-plate type slow cooling furnace in extremely uncontrollable situations, such as when air enters the push-plate type slow cooling furnace and mixes with the atmosphere in the furnace to produce local explosion, wherein the provision of the protective plate can effectively prevent objects in the furnace from flying out and causing accidental injuries.

[0012] As another implementation of the technical solution, the carburizing furnace discharging mechanism and the slow cooling furnace discharging mechanism are both coiled chain pushing structures composed of coiled chain tracks, chains, drive motors, sprockets and pushers, thereby saving space occupied by the above-mentioned discharging mechanisms.

[0013] As another implementation of the present technical solution, the workpiece carburizing production line also includes: several thermocouples, workpiece limiting mechanisms and a central control unit; the several thermocouples are arranged in the slow cooling space; the workpiece limiting mechanism is composed of a limiting rod, an elastic reset member and a travel switch, the limiting rod is movably arranged on the side wall of the furnace body opposite to the slow cooling feed port, the elastic reset member is arranged on the limiting rod, and the travel switch is arranged on the outer side of the furnace body and can be moved and contacted by the limiting rod; the central control unit is electrically connected to the several thermocouples, the travel switch, the sealed furnace door of the carburizing furnace discharge port, the carburizing furnace discharge mechanism, the workpiece quenching moving mechanism, the sealed furnace door of the slow cooling feed port and the slow cooling discharge port, the guide chain moving mechanism, the gas circulation mechanism, the heat preservation mechanism, the cooling mechanism, the slow cooling discharge ventilation chamber, the exhaust gas discharge mechanism, the protective gas intake mechanism and the slow cooling furnace discharge mechanism. In this way, the fully automated operation of the workpiece carburizing production line can be realized, thereby saving the investment in labor costs.

[0014] In order to solve the above technical problems, the present technical solution also provides a workpiece heat treatment method, which comprises the following steps:

[0015] Carburizing operation: Several workpieces are carburized in a push-plate carburizing furnace;

[0016] Selective operation of subsequent process: according to the requirements of subsequent process, the carburizing furnace discharge mechanism of the push-plate carburizing furnace pushes the carburized workpieces one by one to the sealed front chamber of the quenching chamber sealed with the carburizing furnace discharge port of the push-plate carburizing furnace for quenching operation, or pushes the carburized workpieces one by one through the sealed front chamber to the workpiece feeding position of the push-plate slow cooling furnace sealed with the sealed front chamber for slow cooling operation, or selectively pushes the carburized workpieces to the sealed front chamber or the workpiece feeding position for cross quenching operation or slow cooling operation;

[0017] Quenching operation: The workpiece in the sealed front chamber is driven by the workpiece quenching moving mechanism to descend to the quenching tank for quenching, and then driven by the workpiece quenching moving mechanism to ascend to the discharge chamber sealed and isolated from the sealed front chamber for output of the workpiece;

[0018] Slow cooling operation: The workpiece located at the workpiece feeding position is driven by the guide chain moving mechanism to leave the workpiece feeding position and move step by step toward the slow cooling outlet. At the same time, the workpiece feeding position is pushed into the next workpiece to be slow cooled, and the protective gas intake mechanism arranged near the slow cooling outlet injects protective gas into the push-plate type slow cooling furnace, and the flow direction of the protective gas is opposite to the moving direction of the workpiece, so that the protective gas dilutes the carburizing atmosphere at the workpiece feeding position and is discharged from the push-plate type slow cooling furnace through the exhaust gas discharge mechanism arranged near the slow cooling feed port. During the movement, the workpiece is first kept warm by the insulation mechanism and then cooled by the cooling mechanism. After that, it is pushed to the slow cooling outlet ventilation chamber by the slow cooling furnace discharge mechanism to output the workpiece.

[0019] Accordingly, the workpiece heat treatment method can be used to perform selective quenching or slow cooling process operations on the workpiece after carburizing treatment, and mass production of the workpiece slow cooling process can be achieved in a safe atmosphere environment that prevents air from entering, thereby improving the heat treatment efficiency and quality of the workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A top view of a specific embodiment of a workpiece carburizing production line of the present invention;

[0021] Figure 2 It is a schematic diagram of the push-plate carburizing furnace, the sealed front chamber and the push-plate slow cooling furnace in the present invention connected in sequence;

[0022] Figure 3 It is a side sectional view of the push-plate type slow cooling furnace in the present invention;

[0023] Figure 4 It is a top cross-sectional view of the push-plate type slow cooling furnace in the present invention;

[0024] Figure 5 It is a cross-sectional view of the insulation section of the push-plate type slow cooling furnace in the present invention;

[0025] Figure 6 It is a cross-sectional view of the cooling section of the push-plate type slow cooling furnace in the present invention;

[0026] Figure 7 is a front cross-sectional view of the quenching chamber of the present invention;

[0027] Figure 8 is a schematic diagram of the guide chain moving mechanism in the present invention;

[0028] Fig. 9 It is a cross-sectional view of the guide chain moving mechanism in the present invention;

[0029] Fig.10 It is a schematic diagram of the cooling mechanism in the present invention.

[0030] Explanation of symbols in the accompanying drawings:

[0031] 1 Workpiece carburizing production line; 10 Push-plate carburizing furnace; 11 Carburizing furnace discharge port; 12 Sealed furnace door; 13 Carburizing furnace discharge mechanism; 20 Quenching chamber; 21 Sealed front chamber; 22 Discharge chamber; 23 Quenching tank; 24 Quenching elevator; 25 Quenching lift; 251 Quenching platform; 252 Frame; 26 Transfer platform; 27 Transfer push chain; 28 Discharge elevator; 29 Discharge lift; 291 Discharge platform; 292 Frame; 201 Air baffle; 202 Isolation door lifting mechanism; 30 Push-plate slow cooling furnace; 31 Furnace body; 311 Slow cooling space; 312 Slow cooling feed port; 313 Slow cooling discharge port; 32 Guide chain moving mechanism; 321 C-shaped groove rail; 3211 groove rail; 322 Fixed groove; 323 Guide chain; 324 Pulling head; 325 reciprocating drive motor; 33 gas circulation mechanism; 331 circulation fan; 332 air guide top plate; 333 air guide side plate; 34 heat preservation mechanism; 35 cooling mechanism; 351 serpentine tube array; 352 heat dissipation fin; 36 slow cooling discharge ventilation chamber; 37 exhaust gas discharge mechanism; 38 protective gas intake mechanism; 39 slow cooling furnace discharge mechanism; 301 explosion-proof pressure relief device; A workpiece. DETAILED DESCRIPTION

[0032] 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.

[0033] like Figures 1 to 6 As shown, it is a schematic diagram of a specific embodiment of the workpiece carburizing production line with both quenching and slow cooling functions of the present invention. The workpiece carburizing production line 1 with both quenching and slow cooling functions (hereinafter referred to as the workpiece carburizing production line 1) includes a push-plate carburizing furnace 10, a quenching chamber 20 and a push-plate slow cooling furnace 30. Among them, the carburizing furnace discharge port 11 of the push-plate carburizing furnace 10 is connected to one side of the sealed front chamber 21 of the quenching chamber 20, and the carburizing furnace discharge port 11 is equipped with a sealed furnace door 12, and a carburizing furnace discharge mechanism 13 is provided on the side wall of the push-plate carburizing furnace 10 opposite to the carburizing furnace discharge port 11. As shown Figure 7 As shown, the quenching chamber 20 in the workpiece carburizing production line 1 of the present invention is a quenching chamber with a special structure, and the quenching chamber 20 mainly includes a sealed front chamber 21, a discharge chamber 22, a quenching tank 23 and a workpiece quenching moving mechanism, wherein the sealed front chamber 21 and the discharge chamber 22 are arranged side by side above the quenching tank 23, and the lower parts of the sealed front chamber 21 and the discharge chamber 22 are both connected to the quenching tank 23, and the quenching medium is contained in the quenching tank 23, and the quenching medium can be quenching oil or quenching salt, etc. The sealed front chamber 21 is isolated from the discharge chamber 22 by the quenching medium in the quenching tank 23, and the workpiece quenching moving mechanism of the quenching chamber 20 is arranged in the sealed front chamber 21, the discharge chamber 22 and the quenching tank 23. Figures 3 to 6As shown, the push-plate slow cooling furnace 30 includes a furnace body 31, a guide chain moving mechanism 32, a gas circulation mechanism 33, a heat preservation mechanism 34, a cooling mechanism 35, a slow cooling discharge ventilation chamber 36, an exhaust gas discharge mechanism 37, a protective gas intake mechanism 38 and a slow cooling furnace discharge mechanism 39. The furnace body 31 is composed of a furnace shell (not shown) and a heat preservation furnace lining (not shown). A slow cooling space 311 is formed inside the furnace body 31, and a slow cooling feed port 312 and a slow cooling discharge port 313 are respectively arranged on the side walls at both ends of the furnace body 31. The slow cooling space 311 is communicated with the slow cooling space 311 and both have sealed furnace doors (not shown). The guide chain moving mechanism 32 and the gas circulation mechanism 33 are both arranged in the furnace body 31 and are respectively located at the bottom and top of the slow cooling space 311. The heat preservation mechanism 34 and the cooling mechanism 35 are also arranged in the furnace body 31 and are respectively located in the slow cooling space 311 adjacent to the slow cooling feed port 312. A section and a section adjacent to the slow cooling discharge port 313, the slow cooling discharge ventilation chamber 36 is arranged on the outside of the slow cooling discharge port 313, the exhaust gas discharge mechanism 37 is arranged on the side wall of the furnace body 31 adjacent to the slow cooling feed port 312 and the top of the slow cooling discharge ventilation chamber 36, and the protective gas intake mechanism 38 is arranged on the side wall of the furnace body 31 adjacent to the slow cooling discharge port 313 and the lower part of the slow cooling discharge ventilation chamber 36, the slow cooling furnace discharge mechanism 39 is arranged on the side wall of the furnace body 31 opposite to the slow cooling discharge port 313, and the slow cooling feed port 312 of the furnace body 31 is connected to the other side of the sealed front chamber 21 of the quenching chamber 20. In this embodiment, the connection between the push plate carburizing furnace 10, the quenching chamber 20 and the push plate type slow cooling furnace 30 is sealed welding, and all external connectors on the above devices are connected using a sealing structure to ensure that the internal operating environment of the workpiece carburizing production line 1 is not in contact with the outside air. The carburizing furnace discharge mechanism 13 and the slow cooling furnace discharge mechanism 39 can both be a coiled chain pusher structure consisting of a coiled chain track, a chain, a drive motor, a sprocket and a pusher head, thereby saving the space occupied by the above-mentioned discharge mechanisms. Figures 1 to 7 As shown, the carburizing furnace discharge mechanism 13 can selectively push the workpiece A processed by the push-plate carburizing furnace 10 to the workpiece quenching moving mechanism in the sealed front chamber 21 or the guide chain moving mechanism 32 in the push-plate slow cooling furnace 30, so that the workpiece quenching moving mechanism drives the workpiece A from the sealed front chamber 21 to the quenching tank 23 for quenching operation, and then outputs the workpiece A through the discharge chamber 22, or the guide chain moving mechanism 32 drives several workpieces A step by step in the slow cooling space 311 for slow cooling operation, and then the slow cooling furnace discharge mechanism 39 pushes the workpiece A after slow cooling into the slow cooling discharge ventilation chamber 36 to output the workpiece A.

[0034] The slow cooling discharge ventilation chamber 36 in this embodiment is a prior art and is widely used in the field of workpiece heat treatment. The slow cooling discharge ventilation chamber 36 has a relatively sealed ventilation space, a discharge mechanism, and a fire curtain is usually arranged under the discharge door to isolate the entry of outside air. The slow cooling discharge ventilation chamber can effectively prevent outside air from entering the push-plate type slow cooling furnace through the exhaust gas discharge mechanism and the protective gas intake mechanism during the discharge process of the slow cooling discharge ventilation chamber. Therefore, the safety of the discharge end of the push-plate type slow cooling furnace is greatly ensured. The sealed furnace doors installed at the carburizing furnace discharge port 11, the slow cooling feed port 312 and the slow cooling discharge port 313 in this embodiment are all lifting sealed furnace doors composed of lifting motors, gears, racks, chains, guide channel steels and guide bearings, and the sealed furnace doors are sealed by pressing packing. The lifting sealed furnace doors are also widely used in the field of workpiece heat treatment. Therefore, the specific structure thereof will not be described in detail. In addition, in this embodiment, the air intake mode of the air intake pipeline of the protective gas intake mechanism 38 is divided into a constant mode and a large flow mode. The constant mode is used to maintain the positive pressure in the furnace, while the large flow mode is used to quickly dilute the carburizing atmosphere entering the push-plate slow cooling furnace when the sealed furnace door is closed, or to quickly replace the air entering the slow cooling discharge ventilation chamber. The external discharge pipeline of the exhaust gas discharge mechanism 37 has a pressure-maintaining valve with a counterweight, so that the exhaust gas in the push-plate slow cooling furnace and the slow cooling discharge ventilation chamber can only be discharged to the outside according to the set furnace pressure, and the pressure-maintaining valve is a one-way structure and cannot be opened in the reverse direction, so that the outside air cannot enter the device through the pressure-maintaining valve. At the same time, the discharge port of the external discharge pipeline also has an ignition burner with a combustion-supporting atmosphere to ignite the discharged combustible atmosphere, so that the discharged exhaust gas meets environmental protection requirements.

[0035] Specifically, if Figure 7As shown, the workpiece quenching moving mechanism includes a quenching elevator 24, a quenching lifting platform 25, a transfer platform 26, a transfer push chain 27, a discharge elevator 28 and a discharge lifting platform 29. Among them, the quenching elevator 24 is installed on the outer side of the top wall of the sealed front chamber 21, and its lifting drive end vertically penetrates the top wall of the sealed front chamber 21 downward and is located in the sealed front chamber 21. The quenching lifting platform 25 is arranged in the sealed front chamber 21 so as to be movable up and down, and the quenching lifting platform 25 is composed of a quenching platform 251 and a frame 252 surrounding the upper part of the quenching platform 251. The quenching platform 251 is flush with the bottom of the sealed front chamber 21 in the initial state, and the lifting drive end of the quenching elevator 24 is fixedly connected to the top of the frame 252 of the quenching lifting platform 25. The transfer platform 26 is horizontally arranged in the quenching tank 23, and corresponding slots (not shown) are arranged corresponding to the quenching lifting platform 25 and the discharge lifting platform 29. The transfer push chain 27 is composed of an L-shaped chain guide plate, a chain, a driving motor and a driving wheel. The L-shaped chain guide plate is installed outside the sealed front chamber 21 and its vertical section is inserted into the quenching tank 23 so that its horizontal section is against the upper side of the transfer platform 26. The chain is movably embedded in the L-shaped chain guide plate. The driving motor is installed above the quenching tank 23 and located beside the L-shaped chain guide plate. The driving wheel is installed at the driving end of the driving motor and is connected to the chain in meshing driving. The discharge elevator 28 is installed on the outer side of the top wall of the discharge chamber 22 and its lifting driving end vertically passes through the top wall of the discharge chamber 22 downward and is located in the discharge chamber 22. The discharge lifting platform 29 is arranged in the discharge chamber 22 so as to be movable up and down. The discharge lifting platform 29 is composed of a discharge platform 291 and a frame 292 surrounding the upper part of the discharge platform 291. The lifting driving end of the discharge lift 28 is fixedly connected to the top of the frame 292 of the discharge lifting platform 29. After the carburizing furnace discharge mechanism 13 pushes the workpiece A to the quenching platform 251, the quenching lift 24 drives the quenching lift 25 to descend to the corresponding slot of the transfer platform 26 and make the quenching platform 251 flush with the upper side of the transfer platform 26. At this time, the workpiece A performs a quenching operation in the quenching medium. After the quenching of the workpiece A is completed, the drive motor of the transfer push chain 27 drives the chain to push the workpiece A to the discharge platform 291 of the discharge lifting platform 29 that descends to the corresponding slot of the transfer platform 26, and then the discharge lift 28 drives the discharge lifting platform 29 to the discharge chamber 22 to output the workpiece A. The quenching chamber 20 physically isolates the sealed front chamber 21 from the discharge chamber 22 through the quenching medium, so as to effectively prevent air from entering the sealed front chamber 21 from the discharge end, and also prevent the quenching steam generated after the quenching of the workpiece A from being dissipated to the outside of the quenching chamber 20 through the discharge chamber 22, thereby causing the loss of the quenching medium and causing environmental pollution. Therefore, the special structure of the quenching chamber 20 can prevent the carburizing atmosphere from mixing with the air and causing an explosion, thereby improving the safety of the operation of the quenching chamber 20, and can prevent the oxygen in the air from oxidizing the workpiece A, thereby ensuring the quenching quality of the workpiece A, and can also prevent the loss of quenching steam, thereby reducing the investment in material costs.

[0036] In addition, if Figure 7 As shown, the quenching chamber 20 may also include an air baffle plate 201, an isolation door lifting mechanism 202, an exhaust gas discharge port (not shown) and a protective gas inlet port (not shown). The air baffle plate 201 is vertically arranged at the upper part of the quenching tank 23 and is located between the sealed front chamber 21 and the discharge chamber 22, and the lower end of the air baffle plate 201 is inserted below the liquid level of the quenching medium in the quenching tank 23 to isolate the liquid level of the quenching medium in the quenching tank 23. The isolation door lifting mechanism 202 includes an isolation door, a lifting motor and an isolation plate. The isolation door is vertically and movable up and down on the quenching tank 23 between the sealed front chamber 21 and the discharge chamber 22. The lifting motor is installed above the quenching tank 23 and is located beside the isolation door and is connected to the isolation door drive. The isolation plate is vertically and corresponding to the position of the isolation door and is arranged below the transfer platform 26. The lifting motor can drive the isolation door to move downward and abut against the transfer platform 26, so that the isolation door and the isolation plate separate the quenching tank 23 into a quenching area and a discharge area. The exhaust gas discharge port and the protective gas inlet are both arranged in the sealed front chamber 21. The arrangement of the air isolation plate 201 and the isolation door lifting mechanism 202 can further prevent outside air from entering the sealed front chamber 21 from the discharge chamber 22, and can prevent quenching steam from flowing from the sealed front chamber 21 to the discharge chamber 22; and the arrangement of the exhaust gas discharge port and the protective gas inlet can effectively reduce the influence of the carburizing atmosphere on the subsequent process.

[0037] Furthermore, combined with Figure 4 As shown, the push-plate carburizing furnace 10, the quenching chamber 20 and the push-plate slow cooling furnace 30 are all provided with two parallel guide rails connected to each other (not shown in the figure and only the guide rails in the push-plate slow cooling furnace are shown), so as to push and transfer the workpiece A between the various devices of the workpiece carburizing production line 1, wherein the guide rails in the push-plate carburizing furnace 10 are generally made of silicon carbide guide rails or heat-resistant steel guide rails, while the guide rails in the quenching chamber 20 and the push-plate slow cooling furnace 30 are made of heat-resistant steel guide rails. The guide rails of the quenching chamber 20 are arranged on the quenching platform and the discharge platform.

[0038] In this embodiment, combined with Figure 8 and 9 As shown, the chain guide moving mechanism 32 is arranged between two parallel guide rails at the bottom of the slow cooling space 311 along the direction from the slow cooling feed port 312 to the slow cooling discharge port 313. The chain guide moving mechanism 32 includes a C-shaped groove rail 321 formed by sequentially assembling several sections of groove rails 3211, several fixed grooves 322, a chain guide 323, a pulling head 324 and a reciprocating drive motor 325, wherein the several sections of groove rails 3211 include a plurality of straight-line-segment groove rails (not shown in the figure, this part of the groove rails is located at a position parallel to the bottom of the slow cooling space 311) and a plurality of arc-line-segment groove rails (not shown in the figure, this part of the groove rails is located at the turning point of the C-shaped groove rail 321). Fig. 9 As shown, each groove rail 3211 is composed of two channel steels with their grooves facing each other and spaced apart, and the C-shaped groove rail 321 is arranged between two parallel guide rails at the bottom of the slow cooling space 311. The plurality of fixed grooves 322 are fixedly arranged on the inner side of the C-shaped groove rail 321 at the same distance corresponding to the plurality of groove rails 3211, and each groove rail 3211 is fixedly embedded in the groove of each fixed groove 322. The guide chain 323 is movably embedded in the C-shaped groove rail 321. The pulling head 324 is fixedly combined on the upper side of the guide chain 323 adjacent to the slow cooling feed port 312 and exposed on the upper side of the C-shaped groove rail 321. The reciprocating drive motor 325 is installed at the bottom of the furnace body 31 and its driving end is meshed and driven by the guide chain 323 through a sprocket. The wrapping support structure of the guide chain 323 by the C-shaped groove rail 321 and the fixed groove 322 can effectively strengthen the structural strength of the guide chain moving mechanism 32, thereby improving the carrying capacity of the guide chain moving mechanism 32; and because there is a height difference between the guide rail at the bottom of the slow cooling space 311 and the guide chain moving mechanism 32, the workpiece A pushed into the slow cooling space 311 is placed on the guide rail, and the reciprocating drive motor 325 drives the guide chain 323 in the C-shaped groove rail 321 to drive the pulling head 324 to move reciprocatingly, so that the workpiece A fed through the slow cooling feed port 312 can be pushed and pressed by the pulling head 324. The workpiece A in the top front is moved, so that several workpieces A in the slow cooling space 311 are moved one by one along the guide rail in a step-by-step manner toward the slow cooling outlet 313. The conveying structure in which the several workpieces A are closely together can effectively reduce the size of the empty and enclosed space in the slow cooling space 311, thereby effectively reducing the possibility of deflagration or explosion of the push-plate type slow cooling furnace 30; in addition, the workpiece conveying mechanism in the furnace, which is mainly composed of the C-shaped groove rail 321, the guide chain 323 and the reciprocating drive motor 325, can also effectively reduce the complexity of the mechanism and reduce the occupation of the bottom space of the push-plate type slow cooling furnace 30.

[0039] In this embodiment, combined with Figure 3 , 5As shown in Figure 6, the gas circulation mechanism 33 is composed of several circulation fans 331, an air guide top plate 332 and two air guide side plates 333. Among them, the several circulation fans 331 are arranged at the top of the slow cooling space 311 at the same distance along the direction from the slow cooling feed inlet 312 to the slow cooling outlet 313. The air guide top plate 332 is provided with several fan holes (not shown) corresponding to the several circulation fans 331, and the air guide top plate 332 is horizontally arranged at the top of the slow cooling space 311 so that the circulation fans 331 are correspondingly mounted on the fan holes. The two air guide side plates 333 are vertically arranged in the slow cooling space 311 and are located on both sides of the two parallel guide rails, and the upper side edges of the two air guide side plates 333 are respectively combined and fixed with the two side edges of the air guide top plate 332. The airflow generated by the circulating fan 331 is guided by the air guide top plate 332 and the air guide side plates 333 so that the airflow can flow quickly and orderly in a fixed direction, thereby ensuring that the workpiece is cooled evenly and slowly, thereby improving the quality of the product.

[0040] In this embodiment, combined with Figure 5 As shown, the heat preservation mechanism 34 is composed of a plurality of heating elements, which are arranged in a section of the slow cooling space 311 adjacent to the slow cooling feed port 312 and are respectively located between the two side walls of the furnace body 31 and the two air guide side plates 333. Figure 6 and Fig.10 As shown, the cooling mechanism 35 is composed of several serpentine tubes 351 and several heat dissipation fins 352 sleeved on the serpentine tubes 351. The several serpentine tubes 351 are arranged in a section of the slow cooling space 311 adjacent to the slow cooling outlet 313 and are respectively located between the two side walls of the furnace body 31 and the two wind guide side plates 333. The cooling circulation medium flowing in the cooling mechanism 35 adopts liquid high-efficiency cooling oil. Compared with cooling water, the cooling oil has a higher vaporization temperature than the cooling water, which can reduce the problem of cooling pipe bursting caused by liquid vaporization under abnormal conditions. In this embodiment, the circulation of the cooling oil in the cooling mechanism adopts a closed cycle, and the circulation system is equipped with an oil replenishment barrel. The oil circulation relies on two circulating oil pumps of different sizes. The large oil pump is used for rapid cooling of the workpiece, and the small oil pump is used for uniform cooling. The heat preservation mechanism 34 and the cooling mechanism 35 divide the slow cooling space 311 into a heat preservation section and a cooling section, so that the workpiece A can be subjected to a slow cooling operation according to the slow cooling process requirements (first heating and heat preservation and then cooling and lowering the temperature) during its movement in the slow cooling space 311 .

[0041] In this embodiment, the workpiece carburizing production line 1 also includes two explosion-proof pressure relief devices 301, each of which is composed of a flange, an explosion-proof membrane, an insulation layer and a protective plate. Among them, the explosion-proof membrane is arranged in the flange hole of the flange, the insulation layer is arranged at the bottom of the flange, and the protective plate is arranged at the top of the flange. Explosion-proof pressure relief ports (not shown in the figure) are provided at the top of the furnace body 31 and the top of the slow cooling and discharging ventilation chamber 36. The two explosion-proof pressure relief devices 301 are respectively fixedly mounted on the explosion-proof pressure relief ports of the furnace body 31 and the slow cooling and discharging ventilation chamber 36 with flanges. The explosion-proof pressure relief device 301 can be used as a safety device for emergency pressure relief of the push-plate type slow cooling furnace in extremely uncontrollable situations, such as when air enters the push-plate type slow cooling furnace and mixes with the atmosphere in the furnace to produce local explosion, wherein the setting of the protective plate can effectively prevent objects in the furnace from flying out and causing accidental injuries. In addition, an inspection door (not shown) communicating with the slow cooling space 311 and having an observation window is provided on the furnace body of the push-plate type slow cooling furnace 30 so that operators can perform maintenance on the push-plate type slow cooling furnace during shutdown of the workpiece carburizing production line.

[0042] The workpiece carburizing production line of the present invention also has another embodiment, which is not shown in the figure. The device structure in this other embodiment is roughly the same as the above embodiment, and the only difference is that the workpiece carburizing production line can also include several thermocouples, workpiece limiting mechanisms and a central control unit. Among them, the several thermocouples are arranged in the slow cooling space. The workpiece limiting mechanism is composed of a limiting rod, an elastic reset member and a travel switch. The limiting rod is movably arranged on the side wall of the furnace body opposite to the slow cooling feed port, the elastic reset member is arranged on the limiting rod, and the travel switch is arranged on the outside of the furnace body and can be moved and contacted by the limiting rod. The central control unit is electrically connected to the several thermocouples, the travel switch, the sealed furnace door of the carburizing furnace discharge port, the carburizing furnace discharge mechanism, the workpiece quenching moving mechanism, the sealed furnace door of the slow cooling feed port and the slow cooling discharge port, the guide chain moving mechanism, the gas circulation mechanism, the heat preservation mechanism, the cooling mechanism, the slow cooling discharge ventilation chamber, the exhaust gas discharge mechanism, the protective gas intake mechanism and the slow cooling furnace discharge mechanism. The workpiece limiting mechanism can ensure that the carburizing furnace discharge mechanism accurately pushes the carburized workpiece to the workpiece feeding position in the push-plate slow cooling furnace (i.e., the designated position of the guide rail). The central control unit can be composed of a programmable logic control circuit (PLC) or a centralized control circuit. In view of the fact that the programmable logic control circuit or the centralized control circuit is currently used to control the operating state of each device (such as the push-plate carburizing furnace, quenching chamber and push-plate slow cooling furnace in the present invention) according to the detection data of relevant sensors (thermocouples, furnace pressure detectors, travel switches, etc.) and / or the set process implementation steps, it is a widely used and common control method in the field of automatic control, that is, the existing control technology. Therefore, the operation process of the central control unit used in the present invention to control the above-mentioned components will not be described in detail. Therefore, through the centralized control of the central control unit, the fully automated operation of the workpiece carburizing production line can be realized, thereby saving the investment in labor costs. In addition, in order to improve production safety, a furnace pressure detector electrically connected to the central control unit can be installed in the push-plate slow cooling furnace and the slow cooling discharge ventilation chamber to control the protective gas intake mechanism to replenish protective gas when the furnace pressure drops, so as to maintain positive pressure in the furnace.

[0043] In addition, the present invention also provides a workpiece heat treatment method, the steps of which include:

[0044] Carburizing operation: Carburizing several workpieces in a push-plate carburizing furnace;

[0045] Selective operation of subsequent process: according to the requirements of subsequent process, the carburizing furnace discharge mechanism of the push-plate carburizing furnace pushes the carburized workpieces one by one to the sealed front chamber of the quenching chamber sealed with the carburizing furnace discharge port of the push-plate carburizing furnace for quenching operation, or pushes the carburized workpieces one by one through the sealed front chamber to the workpiece feeding position of the push-plate slow cooling furnace sealed with the sealed front chamber for slow cooling operation, or selectively pushes the carburized workpieces to the sealed front chamber or the workpiece feeding position for cross quenching operation or slow cooling operation;

[0046] Quenching operation: The workpiece in the sealed front chamber is driven by the workpiece quenching moving mechanism to descend to the quenching tank for quenching, and then driven by the workpiece quenching moving mechanism to ascend to the discharge chamber sealed and isolated from the sealed front chamber for output of the workpiece;

[0047] Slow cooling operation: The workpiece located at the workpiece feeding position is driven by the guide chain moving mechanism to leave the workpiece feeding position and move step by step toward the slow cooling outlet. At the same time, the workpiece feeding position is pushed into the next workpiece to be slow cooled, and the protective gas intake mechanism arranged near the slow cooling outlet injects protective gas into the push-plate type slow cooling furnace, and the flow direction of the protective gas is opposite to the moving direction of the workpiece, so that the protective gas dilutes the carburizing atmosphere at the workpiece feeding position and is discharged from the push-plate type slow cooling furnace through the exhaust gas discharge mechanism arranged near the slow cooling feed port. During the movement, the workpiece is first kept warm by the insulation mechanism and then cooled by the cooling mechanism. After that, it is pushed to the slow cooling outlet ventilation chamber by the slow cooling furnace discharge mechanism to output the workpiece.

[0048] Through the above workpiece heat treatment method, selective quenching or slow cooling process operations can be performed on the workpiece after carburizing treatment, and large-scale production of the workpiece slow cooling process can be achieved in a safe atmosphere environment that prevents air from entering, thereby improving the heat treatment efficiency and quality of the workpiece.

[0049] Accordingly, the operation process of the workpiece carburizing production line of the present invention is roughly as follows: the sealed furnace door of the carburizing furnace discharge port is opened, and the carburizing furnace discharge mechanism pushes the carburized workpiece out of the push-plate carburizing furnace along the guide rail according to the setting of the process flow; when the process flow is set to a quenching process, the carburizing furnace discharge mechanism pushes the carburized workpiece into the sealed front chamber of the quenching chamber, the carburizing furnace discharge mechanism is retracted and the sealed furnace door of the carburizing furnace discharge port is closed, and the workpiece is driven by the workpiece quenching moving mechanism to descend to the quenching tank. The workpiece is quenched in the ignition medium, and then the workpiece is transferred to the discharge platform, and then the discharge elevator drives the discharge platform to rise to the discharge chamber to output the quenched workpiece; when the process flow is set to the slow cooling process, the carburizing furnace discharge mechanism pushes the carburized workpiece into the sealed front chamber of the quenching chamber, at this time, the sealed furnace door of the slow cooling feed port of the push-plate type slow cooling furnace is opened, and the carburizing furnace discharge mechanism continues to push the workpiece to the workpiece feeding position in the slow cooling space, and then the carburizing furnace discharge mechanism is retracted and the sealed furnace doors of the carburizing furnace discharge port and the slow cooling feed port are closed, and the workpiece is driven by the guide chain moving mechanism to move step by step in the slow cooling space, and for each workpiece position moved toward the slow cooling discharge port, a workpiece to be slow cooled will be fed into the workpiece feeding position, and the workpiece is first kept warm by the insulation mechanism of the insulation section during the movement and then cooled by the cooling mechanism of the cooling section, and the gas circulation mechanism ensures the circulation of the atmosphere in the slow cooling space during the entire workpiece slow cooling process, and the protective gas intake mechanism and the exhaust gas discharge mechanism maintain the slow cooling atmosphere (diluted The carburizing atmosphere is released and eliminated) and the positive pressure in the furnace. When the workpiece moves to the slow cooling discharge port, the sealed furnace door of the slow cooling discharge port is opened, and the workpiece after the slow cooling treatment is pushed into the slow cooling discharge ventilation chamber by the slow cooling furnace discharge mechanism. The slow cooling furnace discharge mechanism is retracted and the sealed furnace door of the slow cooling discharge port is closed. The discharge door of the slow cooling discharge ventilation chamber is opened and the workpiece is output by its discharge mechanism. After that, the discharge door of the slow cooling discharge ventilation chamber is closed and the ventilation space is ventilated with protective gas, and then the slow cooling discharge operation of the next workpiece is carried out. In addition, it should be noted that the workpiece in the present invention is placed on a tray to move on the guide rails of each device, and the number of trays arranged in the workpiece carburizing production line is determined according to the process requirements, the slow cooling speed and the overall discharge cycle of the production line.

[0050] To sum up, the workpiece carburizing production line in the present invention is to seal and connect the push-plate carburizing furnace, quenching chamber and push-plate slow cooling furnace in sequence according to the workpiece heat treatment process flow, and use the sealed front chamber of the quenching chamber as a "transfer platform". The workpiece after carburizing treatment by the push-plate carburizing furnace can be pushed to the sealed front chamber by the carburizing furnace discharge mechanism to implement the quenching process, and can also be pushed to the slow cooling space of the push-plate slow cooling furnace through the sealed front chamber by the carburizing furnace discharge mechanism to implement the slow cooling process. This selective operation can make the workpiece carburizing production line meet multiple process steps at the same time, thereby reducing the cost of production equipment investment and saving production land use; and the push-plate slow cooling furnace can simultaneously meet the slow cooling operation of several workpieces in the slow cooling space, and the conveying structure of several workpieces close together can also reduce the volume of the enclosed space in the slow cooling space, so that not only can large-scale production of workpieces be achieved and the production efficiency of the workpiece carburizing production line be improved, but also the risk of explosion can be reduced. In addition, before the quenching process and during the slow cooling process, the workpiece is required not to be oxidized at high temperature, and in the process of transferring the workpiece to the sealed front chamber or slow cooling space, the carburizing atmosphere in the push-plate carburizing furnace will inevitably enter the quenching chamber and the push-plate slow cooling furnace. Since the carburizing atmosphere contains a large amount of hydrogen and carbon monoxide atmosphere, and during the implementation of the slow cooling process, the temperature in the push-plate slow cooling furnace will drop from about 900°C to about 100°C, which will gradually fall below the explosion safety temperature of 750°C. Moreover, since the push-plate slow cooling furnace has to carry out slow cooling operations on multiple workpieces at the same time, the size of the enclosed space is large, and sparks will inevitably be generated during the transfer of the workpiece. Therefore, in order to prevent the carburized workpiece from being oxidized in the subsequent process, and to prevent the explosion hazard caused by a small amount of air entering the push-plate slow cooling furnace, the quenching chamber of the present technical solution arranges the sealed front chamber and the discharge chamber on the upper part of the quenching tank and physically isolates the sealed front chamber and the discharge chamber with the quenching medium to effectively prevent air from entering through the quenching chamber. The workpiece carburizing production line; and the slow cooling discharge ventilation chamber arranged outside the slow cooling discharge port of the push-plate type slow cooling furnace can also effectively prevent air from entering the workpiece carburizing production line through the discharge end of the push-plate type slow cooling furnace; furthermore, the exhaust gas discharge mechanism and the protective gas intake mechanism are respectively arranged on the side wall of the furnace body near the slow cooling feed port and the slow cooling discharge port, which can make the protective gas (usually nitrogen) flow from the slow cooling discharge port to the slow cooling feed port, that is, from the low temperature section to the high temperature section (the low temperature section has a temperature lower than the explosion safety temperature of 750 °C and there is a great risk of explosion), thereby effectively avoiding the risk of explosion in the push-plate type slow cooling furnace, and maintaining the furnace pressure in the push-plate type slow cooling furnace, and because the concentration of the carburizing atmosphere at the slow cooling feed inlet is relatively high, the protective gas can also dilute the carburizing atmosphere, and the exhaust gas discharge mechanism arranged at the slow cooling feed inlet is more conducive to removing the carburizing atmosphere and maintaining the stability of the furnace pressure, and preventing the carburizing atmosphere from diffusing and crosstalking into the slow cooling space to the greatest extent, thereby effectively improving the operation safety of the workpiece carburizing production line.

[0051] 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 workpiece carburizing production line with both quenching and slow cooling functions, comprising: Push plate carburizing furnace and quenching chamber; The carburizing furnace discharge port of the push-plate carburizing furnace is connected and communicated with one side of the sealed front chamber of the quenching chamber, and the carburizing furnace discharge port is equipped with a sealed furnace door, and a carburizing furnace discharge mechanism is arranged on the side wall of the push-plate carburizing furnace opposite to the carburizing furnace discharge port; the quenching chamber comprises: the sealed front chamber, the discharge chamber, the quenching tank and the workpiece quenching moving mechanism, the sealed front chamber and the discharge chamber are located above the quenching tank and are communicated with the quenching tank, the workpiece quenching moving mechanism is arranged in the sealed front chamber, the discharge chamber and the quenching tank; it is characterized in that it also includes: a push-plate type slow cooling furnace, the push-plate type slow cooling furnace The cold furnace comprises: a furnace body, a guide chain moving mechanism, a gas circulation mechanism, a heat preservation mechanism, a cooling mechanism, a slow cooling discharge ventilation chamber, an exhaust gas discharge mechanism, a protective gas intake mechanism and a slow cooling furnace discharge mechanism, a slow cooling space is formed inside the furnace body, and a slow cooling feed port and a slow cooling discharge port which are connected to the slow cooling space and have sealed furnace doors are respectively arranged on the side walls at both ends of the furnace body, the guide chain moving mechanism and the gas circulation mechanism are both arranged in the furnace body and are respectively located at the bottom and top of the slow cooling space, the heat preservation mechanism and the cooling mechanism are both arranged in the furnace body and are respectively located in the slow cooling space adjacent to the slow cooling feed port The slow cooling furnace discharge mechanism is arranged on the side wall of the furnace body opposite to the slow cooling discharge port, and the slow cooling discharge ventilation chamber is connected to the other side of the sealed front chamber of the quenching chamber. The carburizing furnace discharging mechanism can selectively push the workpieces processed by the push-plate carburizing furnace to the workpiece quenching moving mechanism in the sealed front chamber or the guide chain moving mechanism in the push-plate slow cooling furnace, so that the workpiece quenching moving mechanism drives the workpiece from the sealed front chamber to the quenching tank for quenching operation, and then outputs the workpiece through the discharging chamber, or the guide chain moving mechanism drives several workpieces in a step-by-step manner in the slow cooling space for slow cooling operation, and then the slow cooling furnace discharging mechanism pushes the workpiece after slow cooling into the slow cooling discharging ventilation chamber to output the workpiece.

2. The workpiece carburizing production line according to claim 1, characterized in that: The workpiece quenching moving mechanism includes: a quenching elevator, a quenching lifting platform, a transfer platform, a transfer push chain, a discharge elevator and a discharge lifting platform; the quenching elevator is installed on the outer side of the top wall of the sealed front chamber and its lifting drive end vertically passes through the top wall of the sealed front chamber downward and is located in the sealed front chamber; the quenching lifting platform can be moved up and down and is arranged in the sealed front chamber and the quenching lifting platform is composed of a quenching platform and a frame surrounded by the upper part of the quenching platform. In the initial state, the quenching platform is flush with the bottom of the sealed front chamber. The lifting drive end of the elevator is fixedly connected to the top of the frame of the quenching lifting platform; the transfer platform is horizontally arranged in the quenching tank and is provided with slots corresponding to the quenching lifting platform and the unloading lifting platform; the transfer push chain is composed of an L-shaped chain guide plate, a chain, a drive motor and a drive wheel, the L-shaped chain guide plate is installed on the outer side of the sealed front room and its vertical section is passed through the quenching tank so that its horizontal section is against the upper side of the transfer platform, the chain is movably embedded in the L-shaped chain guide plate, the The driving motor is installed above the quenching tank and is located beside the L-shaped chain guide plate. The driving wheel is installed at the driving end of the driving motor and is meshed and driven by the chain; the discharging elevator is installed on the outer side of the top wall of the discharging chamber, and its lifting driving end vertically penetrates the top wall of the discharging chamber downward and is located in the discharging chamber; the discharging lifting platform is arranged in the discharging chamber and can be moved up and down, and the discharging lifting platform is composed of a discharging platform and a frame body surrounded by the upper part of the discharging platform. The lifting driving end of the discharging elevator is connected to the discharging lifting platform. The top of the frame of the table is fixedly connected; the carburizing furnace discharging mechanism pushes the workpiece to the quenching platform, and the quenching elevator is driven to make the quenching lifting platform descend to the slot corresponding to the transfer platform and make the quenching platform flush with the upper side of the transfer platform, and then the drive motor of the transfer push chain drives the chain to push the workpiece to the discharging platform of the discharging lifting platform that has descended to the slot corresponding to the transfer platform, and then the discharging elevator is driven to lift the discharging lifting platform to the discharging chamber to output the workpiece.

3. The workpiece carburizing production line according to claim 2, characterized in that: The quenching chamber also includes: an air baffle plate, an isolation door lifting mechanism, an exhaust gas discharge port and a protective gas inlet; the air baffle plate is vertically arranged at the upper part of the quenching tank and is located between the sealed front chamber and the discharge chamber, and the lower end of the air baffle plate is inserted below the liquid level of the quenching medium in the quenching tank to isolate the liquid level of the quenching medium in the quenching tank; the isolation door lifting mechanism includes: an isolation door, a lifting motor and an isolation plate, the isolation door is vertically and movable up and down on the quenching tank between the sealed front chamber and the discharge chamber, the lifting motor is installed above the quenching tank and is located beside the isolation door and is connected to the isolation door drive, the isolation plate is vertically and corresponding to the position of the isolation door and is arranged below the transfer platform, the lifting motor can drive the isolation door to move downward and abut against the transfer platform, so that the isolation door and the isolation plate separate the quenching tank into a quenching area and a discharge area; the exhaust gas discharge port and the protective gas inlet are both arranged in the sealed front chamber.

4. The workpiece carburizing production line according to claim 1, characterized in that: The push-plate carburizing furnace, quenching chamber and push-plate slow cooling furnace are all provided with two parallel guide rails connected to each other; the guide chain moving mechanism is arranged between the two parallel guide rails at the bottom of the slow cooling space along the direction from the slow cooling feed inlet to the slow cooling discharge outlet, and the guide chain moving mechanism includes: a C-shaped groove rail composed of several sections of groove rails assembled in sequence, several fixed grooves, a guide chain, a pulling head and a reciprocating drive motor, each of the groove rails is composed of two channel steels with their grooves facing each other and spaced apart by a distance, and the C-shaped groove rail is arranged at the slow cooling Between the two parallel guide rails at the bottom of the space, the several fixed grooves correspond to the several sections of the groove rails and are fixedly arranged on the inner side of the C-shaped groove rail at the same interval, and each of the groove rails is fixedly embedded in the groove opening of each fixed groove, the guide chain is movably embedded in the C-shaped groove rail, the pulling head is fixedly combined on the upper side surface of the guide chain adjacent to the slow cooling feed port and exposed on the upper side of the C-shaped groove rail, the reciprocating drive motor is installed at the bottom of the furnace body and its driving end is engaged and driven by the guide chain through a sprocket.

5. The workpiece carburizing production line according to claim 4, characterized in that: The gas circulation mechanism is composed of a plurality of circulation fans, an air guide top plate and two air guide side plates. The plurality of circulation fans are arranged at the top of the slow cooling space at the same intervals along the direction from the slow cooling inlet to the slow cooling outlet. The air guide top plate is provided with a plurality of fan holes corresponding to the plurality of circulation fans. The air guide top plate is horizontally arranged at the top of the slow cooling space and the circulation fans are correspondingly mounted on the fan holes. The two air guide side plates are vertically arranged in the slow cooling space and are located on both sides of two parallel guide rails, and the upper side edges of the two air guide side plates are respectively combined and fixed with the two side edges of the air guide top plate.

6. The workpiece carburizing production line according to claim 5, characterized in that: The heat preservation mechanism is composed of a plurality of heating elements, and the plurality of heating elements are arranged in a section of the slow cooling space adjacent to the slow cooling feed port and are respectively located between the two side walls of the furnace body and the two air guide side plates; the cooling mechanism is composed of a plurality of serpentine tubes and a plurality of heat dissipation fins sleeved on the serpentine tubes, and the plurality of serpentine tubes are arranged in a section of the slow cooling space adjacent to the slow cooling discharge port and are respectively located between the two side walls of the furnace body and the two air guide side plates; the heat preservation mechanism and the cooling mechanism divide the slow cooling space into a heat preservation section and a cooling section.

7. The workpiece carburizing production line according to claim 1, characterized in that: Also includes: Two explosion-proof pressure relief devices are composed of a flange, an explosion-proof membrane, an insulation layer and a protective plate. The explosion-proof membrane is arranged in the flange hole of the flange, the insulation layer is arranged at the bottom of the flange, and the protective plate is arranged at the top of the flange. The top of the furnace body and the top of the slow cooling and discharging ventilation chamber are both provided with explosion-proof pressure relief ports. The two explosion-proof pressure relief devices are respectively fixedly mounted on the explosion-proof pressure relief ports of the furnace body and the slow cooling and discharging ventilation chamber by the flanges.

8. The workpiece carburizing production line according to claim 1, characterized in that: The carburizing furnace discharging mechanism and the slow cooling furnace discharging mechanism are both coiled chain pushing structures composed of a coiled chain track, a chain, a driving motor, a sprocket and a pushing head.

9. The workpiece carburizing production line according to claim 1, characterized in that: Also includes: Several thermocouples, workpiece limiting mechanisms and a central control unit; the several thermocouples are arranged in the slow cooling space; the workpiece limiting mechanism is composed of a limiting rod, an elastic reset member and a travel switch, the limiting rod is movably arranged on the side wall of the furnace body opposite to the slow cooling feed port, the elastic reset member is arranged on the limiting rod, and the travel switch is arranged on the outside of the furnace body and can be moved and contacted by the limiting rod; the central control unit is respectively electrically connected to the several thermocouples, the travel switch, the sealed furnace door of the carburizing furnace discharge port, the carburizing furnace discharge mechanism, the workpiece quenching moving mechanism, the slow cooling feed port and the sealed furnace door of the slow cooling discharge port, the guide chain moving mechanism, the gas circulation mechanism, the insulation mechanism, the cooling mechanism, the slow cooling discharge ventilation chamber, the exhaust gas discharge mechanism, the protective gas intake mechanism and the slow cooling furnace discharge mechanism.

10. A method for heat treatment of a workpiece, characterized in that the steps include: Carburizing operation: Several workpieces are carburized in a push-plate carburizing furnace; Selective operation of subsequent process: according to the requirements of subsequent process, the carburizing furnace discharge mechanism of the push-plate carburizing furnace pushes the carburized workpieces one by one to the sealed front chamber of the quenching chamber sealed with the carburizing furnace discharge port of the push-plate carburizing furnace for quenching operation, or pushes the carburized workpieces one by one through the sealed front chamber to the workpiece feeding position of the push-plate type slow cooling furnace sealed with the sealed front chamber for slow cooling operation, or selectively pushes the carburized workpieces to the sealed front chamber or the workpiece feeding position for cross quenching operation or slow cooling operation; Quenching operation: the workpiece in the sealed front chamber is driven by the workpiece quenching moving mechanism to descend to the quenching tank for quenching, and then driven by the workpiece quenching moving mechanism to ascend to the discharge chamber sealed and isolated from the sealed front chamber to output the workpiece; Slow cooling operation: the workpiece located at the workpiece feeding position is driven by the guide chain moving mechanism to leave the workpiece feeding position and move step by step toward the slow cooling outlet. At the same time, the workpiece feeding position is pushed into the next workpiece to be slow cooled, and the protective gas intake mechanism arranged near the slow cooling outlet injects protective gas into the push-plate type slow cooling furnace, and the flow direction of the protective gas is opposite to the moving direction of the workpiece, so that the protective gas dilutes the carburizing atmosphere at the workpiece feeding position and is discharged from the push-plate type slow cooling furnace through the exhaust gas discharge mechanism arranged near the slow cooling feed port. During the movement, the workpiece is first kept warm by the insulation mechanism and then cooled by the cooling mechanism. After that, it is pushed to the slow cooling outlet ventilation chamber by the slow cooling furnace discharge mechanism to output the workpiece.

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