CN117867442A - Double-row fuel gas pushing disc type controlled atmosphere carburizing and quenching method - Google Patents

Abstract

The invention relates to a double-row fuel gas pushing disc type controllable atmosphere carburizing and quenching method which comprises the steps of feeding, pre-cleaning, pre-oxidizing, bottom feeding, heating, carburizing, diffusing, cooling and heat preserving, oil quenching, post-cleaning, tempering, discharging and the like.

Description

Double-row fuel gas pushing disc type controlled atmosphere carburizing and quenching method

Technical Field

The invention belongs to the technical field of heat treatment processes and equipment, and particularly relates to a double-exhaust gas pushing-disc type controlled atmosphere carburizing and quenching method.

Background

Carburization treatment is carried out on carburized alloy structural steel, quenching treatment is carried out on the carburized alloy structural steel after carburization, austenitic experience in a carburized workpiece can be reduced, impact resistance of the workpiece is improved, and meanwhile, a small amount of carbide can be separated out from the surface of the workpiece after carburization and quenching, so that wear resistance of the workpiece can be further improved.

The existing carburization process is not careful enough in parameter control, and meanwhile, as the carburization process needs to pass through a plurality of devices, the matching relation among the devices is not optimized, so that the temperature of the outer part and the inner part of a workpiece is not uniform enough in the heating and heat preservation process, the heat transfer speed of the inner part of the workpiece is too high or too low in the cooling or quenching process, the heating and heat preservation effects are not ideal, and the different effects in the air cooling or quenching cooling process are not optimal. The existing carburization process takes relatively long time, the workpiece is easy to be heated unevenly, so that the carburization result is poor, the carbide content of the surface of the workpiece is low, and the service performance still cannot meet the requirements.

Chinese patent publication CN104726819a discloses a heat treatment carburizing process for carburizing steel, which sequentially adopts the steps of pre-carburizing, cyclic carburizing, diffusion, quenching, tempering, and the like, and by adding the pre-carburizing process and matching with the cyclic carburizing, a large number of fine carbide particles are formed in the surface carburized layer, so that the wear resistance of the surface is improved. However, by researching the specific process, the internal and external temperatures of the workpiece are not uniform when the workpiece is heated and kept warm, so that the performance is affected.

Disclosure of Invention

Based on the defects in the prior art, the invention provides a double-exhaust pushing-disc type controlled atmosphere carburizing and quenching method.

The method is realized by the following technical means:

a double-row fuel gas pushing disc type controlled atmosphere carburizing and quenching method comprises the following steps:

(1) Feeding, namely placing materials and a material tray on a feeding table; the material is alloy structural steel capable of being carburized.

(2) And (3) pre-cleaning, namely conveying the materials and the material trays which are placed on the feeding table in the step (1) into a pre-cleaning machine for pre-cleaning, wherein the temperature of cleaning liquid is 50-80 ℃, and performing standing water control operation after the pre-cleaning is finished.

(3) And (3) pre-oxidizing, namely pushing the materials and the material trays subjected to the water control operation in the step (2) into a pre-oxidizing furnace for pre-oxidizing treatment, wherein the pre-oxidizing temperature is 350-550 ℃.

(4) The bottom feeding step is carried out through a bottom feeding chamber, the bottom feeding chamber is a sealed furnace chamber, a transversely opened and closed feeding and discharging door is arranged at the bottom of the bottom feeding chamber, after the feeding and discharging door at the bottom is opened, combustible furnace gas in the furnace overflows from the lower part and burns, the burning furnace gas prevents oxygen in air from entering the bottom feeding chamber, the material and a charging tray after the pre-oxidation in the step (3) are pushed into the bottom feeding chamber, and the material and the charging tray are lifted to the track height of the heating chamber through a bottom feeding lifting table arranged in the bottom feeding chamber; and a blocking block for blocking the horizontal displacement of the material tray and the material is arranged in the horizontal direction of the bottom feeding lifting table.

(5) Heating, namely pushing the materials and the material trays fed from the bottom in the step (4) into a heating zone of a heating furnace for heating, wherein the heating temperature is 800-950 ℃, and the heating time is 15-30 min.

(6) Pushing the heated material and the material tray in the step (5) to a carburizing zone for carburizing treatment, wherein the carburizing zone is set to be two zones, the temperature of the first carburizing zone is set to be 830-950 ℃, the carbon potential is (1.05-1.11)% CP, the temperature of the second carburizing zone is 850-960 ℃, the carbon potential is (0.96-1.03)% CP, and the carburizing treatment time is in the range of 15-30 min.

(7) And (3) diffusion, namely pushing the material and the material tray subjected to carburization treatment in the step (6) to a diffusion area for diffusion and temperature equalization, wherein the heat preservation temperature is 830-980 ℃, the carbon potential is (0.85-0.95)% CP, and the heat preservation time is within the range of 15-30 min.

(8) And (3) cooling and preserving heat, namely pushing the material and the material tray subjected to the diffusion treatment in the step (7) into a quenching and preserving heat chamber for preserving heat, wherein the preserving heat temperature is 790-860 ℃, the carbon potential is (0.76-0.85)% CP, and the preserving heat time is within the range of 15-30 min.

(9) Transferring the materials and the material trays subjected to temperature reduction and heat preservation in the step (8) into a first oil quenching tank, and carrying out oil quenching in the first oil quenching tank, wherein the temperature of quenching oil in the first oil quenching tank is 50-69 ℃, and the cooling time of the oil quenching in the first oil quenching tank is 8-12 min; transferring the material and the material tray subjected to oil quenching in the first tank into a second oil quenching tank which is arranged, or directly transferring the material and the material tray subjected to cooling and heat preservation in the step (8) into a preset second oil quenching tank, and performing oil quenching in the second oil quenching tank, wherein the temperature of quenching oil in the second oil quenching tank is 110-128 ℃, and the cooling time of the oil quenching in the second oil quenching tank is 8-12 min; and after quenching, extracting the materials and the material trays from the first oil quenching tank and/or the second oil quenching tank, and controlling oil on a conveying roller way for 15-30 min.

(10) And (3) after-cleaning, conveying the materials and the material trays after oil control in the step (9) into a double-chamber cleaning device, firstly entering an alkali liquor cleaning chamber, after soaking in alkali liquor for 8-15 min, discharging alkali liquor for alkali liquor spray cleaning, wherein the alkali liquor temperature is 62-82 ℃, the alkali liquor spray cleaning time is 7-15 min, conveying the materials and the material trays into a clean water cleaning chamber, carrying out spray cleaning on the materials in the clean water cleaning chamber in a spray manner, and carrying out clean water cleaning in the clean water cleaning chamber for 15-30 min, wherein the water temperature of clean water is 58-76 ℃.

(11) And (3) tempering, namely conveying the materials and the trays obtained after the cleaning treatment in the step (10) into a double-row pushing tray tempering furnace for tempering and heat preservation, alternately pushing the trays in the double-row pushing tray tempering furnace to advance by double main pushing, wherein the tempering and heat preservation temperature is 165-198 ℃, the heat preservation time is 270-540 min, and pushing the materials and the trays out by a pushing chain mechanism for air cooling and cooling.

(12) And (3) unloading, namely unloading the material subjected to tempering in the step (11) to finish the controlled atmosphere carburizing and quenching treatment of the material.

Preferably, the cleaning liquid in the step (2) is water.

Preferably, the step (1) alloy structural steel is one or more of 20CrMnTiH, 20CrMoH, SCM420H, 20MnCr5H or SAE 8620H.

Preferably, the double-row pushing disc tempering furnace used in the step (11) comprises a high-temperature and high-pressure resistant centrifugal fan, an outer air duct, a furnace shell, an inner air duct, a heating device, a wind guiding mechanism, an inner furnace wall and furnace bottom waste oil collecting device, an in-furnace pushing and pulling mechanism, a side furnace door and a furnace door sealing mechanism.

The inner air channel is arranged at the inner top of the furnace shell, and a heating device is arranged in the inner air channel and is of a rod-shaped structure penetrating through the furnace shell; the inner air duct discharges hot air into the hearth through the air guide mechanism.

The inlet end of the outer air channel is communicated with the inner wall of the front end of the furnace shell, the exhaust end of the outer air channel is communicated with the top of the inner wall of the rear end of the furnace shell, the high-temperature and high-pressure resistant centrifugal fan is arranged on the outer air channel, and the high-temperature and high-pressure resistant centrifugal fan sucks hot air at 165-198 ℃ from the hearth through the inlet end of the outer air channel and then discharges the hot air back into the inner air channel through the rear end of the outer air channel and the top of the furnace shell.

The air guide mechanism is an inclined straight plate or arc plate, one part of the straight plate or arc plate is arranged at the outlet of the inner air channel, one end of the straight plate or arc plate is connected with the inner side wall of the furnace shell, the other end of the straight plate or arc plate is inclined downwards, heated hot air is guided from the inner air channel towards the hearth in the directions of materials and the charging trays, the other part of the straight plate or arc plate is arranged below the inlet end of the outer air channel, one end of the straight plate or arc plate is connected with the inner side wall of the furnace shell, and the other end of the straight plate or arc plate is inclined downwards, so that the heated air in the hearth is guided from the hearth towards the direction of the inlet end of the outer air channel.

The waste oil collecting device comprises a metal baffle and an oil collecting groove, wherein the metal baffle is arranged at the inner side wall and the inner top wall of the furnace shell, the metal baffle arranged at the inner top wall is connected with the metal baffle arranged at the inner side wall, the bottom end of the metal baffle arranged at the inner side wall is connected with the oil collecting groove, and the oil collecting groove is arranged at the furnace bottom and is connected with the metal baffle arranged at the inner side wall by a chamfer angle of 5-10 degrees.

The push-pull mechanism in the furnace comprises two rails and two push-pull parts, wherein the push-pull parts are respectively arranged on the two rails and are used for moving the material trays and the materials on the rails.

The side furnace door is provided with two sets of furnace shell side parts which are respectively arranged at the initial end and the final end of the track; the furnace door sealing mechanism is used for sealing the side furnace door.

Preferably, the furnace door sealing mechanism is a high-temperature resistant fiber strip.

Preferably, the pre-oxidation furnace in the step (3) is provided with 5 tray positions and 4 trays, and 5 fuel gas heating radiant tubes are arranged in total, and the installed power is 145-155 kw (fuel gas heating, the installed power is converted power).

Preferably, the steps (5) to (7) are completed in a partition through type hearth, air guide arch top walls are arranged between the partition through areas in the hearth, the tops of the air guide arch top walls are connected with the arch at the top of the hearth, openings are formed in the passing positions of a material tray and a guide rail, a stirring fan is arranged at the top of each area, and the stirring fan is used for stirring the gas in the area, so that the uniformity of the main body of the furnace gas and the furnace temperature in each area is realized; the bottom in the partition through type hearth is provided with a plurality of rows of guide rails, the ratio of the distance between the top ends of the guide rails and the inner wall of the hearth to the height of the material tray is 0.98-0.89, and the guide rails and the interval guide rails are provided with air guide holes which are transverse and penetrate through the two ends of the guide rails.

Preferably, the steps (5) to (7) are completed in a hearth with a partition through type, wherein the zone I is a heating zone, 10 tray positions and 9 trays are arranged in the heating zone, 10 fuel gas heating radiant tubes are arranged in total, the installed power is 235-258 kw, and the heating zone is independently controlled by temperature; the II area is a carburizing area, is provided with 8 material tray positions and 8 trays, is provided with 12 electric heating radiant tubes in total, has the installed power of 125-135 kw, and is provided with independent temperature and carbon potential control components; the III area is a carburization two-area, is provided with 10 material tray positions and 10 trays, is provided with 12 electric heating radiant tubes in total, has the installed power of 125-135 kw, and is provided with independent temperature and carbon potential control components; the IV area is a diffusion area, is provided with 10 material tray positions and 9 trays, is totally provided with 12 electric heating radiant tubes, has the installed power of 85-95 kw, and is provided with independent temperature and carbon potential control components.

Preferably, the plurality of rows of guide rails arranged at the bottom in the partition through type hearth are three rows, and the guide rails are silicon carbide guide rails.

Preferably, the quenching heat preservation chamber in the step (8) is provided with 7 material tray positions and 6 material trays, 12 electric heating radiant tubes are arranged in total, the installed power is 125-135 kw, and the quenching heat preservation chamber is provided with independent temperature and carbon potential control components.

Preferably, the double-chamber cleaning device in the step (10) is of a double-chamber structure, the first chamber is an alkali liquor cleaning chamber, an alkali liquor tank is arranged in the alkali liquor cleaning chamber, tank liquor in the alkali liquor tank adopts an exhaust gas combustion waste heat utilization device to perform main heating parts, 6 electric heating pipes are arranged as auxiliary heating parts for standby, and the electric heating pipes are 30-40 kw electric heating pipes; the second chamber is a clean water cleaning chamber, a clean water tank is arranged in the clean water cleaning chamber, the tank liquor of the clean water tank adopts an exhaust gas combustion waste heat utilization device to carry out main heating parts, 4 electric heating pipes are arranged as auxiliary heating parts for standby, and the electric heating pipes are 20-28 kw.

The installed power of the gas heating is converted into the equivalent installed power of the electric heating.

The invention has the technical effects that:

(1) According to the invention, the specific structure of the double-row pushing disc tempering furnace is specifically arranged, so that the specific workpiece subjected to specific carburizing and quenching can be subjected to more uniform and stable tempering treatment. By arranging the outer air duct and the high-temperature-resistant high-pressure centrifugal fan, the hot air in the tempering furnace realizes the outer circulation, thereby ensuring the uniformity of the temperature of each region in the hearth, moving in a way of alternately pushing and advancing by matching with the double main pushing in the tempering furnace (one guide rail advancing way of the tempering furnace is converted into two guide rails advancing way of the tempering furnace, the feed trays are alternately distributed in the two guide rails, the feed trays of the two guide rails in the tempering furnace are not adjacent and are arranged at intervals, so that excessive heat accumulation is caused at the edges of the materials), and the uniformity of heating the materials is further ensured; the specific heating device is arranged in the furnace top air channel, so that the technical problem that the furnace is required to be shut down when the existing heating wire is replaced after heating is solved, the quick replacement function can be realized through whole extraction and replacement, the quick replacement of a heating core without shutdown is realized, and the tempering integral efficiency is improved on the premise of ensuring the temperature uniformity in the furnace; through setting up interior oven and the stove bottom waste oil collection device of specific structure, realized the reliable removal of oil stain in the stove, only need regularly clear away the oil groove after collecting can, avoided the bad influence of oil stain to refractory material, compare with traditional tempering furnace, do not need high temperature burning to remove oil stain, can gather oil recovery in tempering process, reduced the environmental protection pollution of burning oil smoke and the risk of catching fire of furnace.

(2) According to the invention, the bottom feeding chamber in the step (4) is arranged in a mode of not introducing inert gas by combining the bottom door opening structure with the combustible gas in the furnace and the arrangement mode, so that the cost is greatly reduced under the condition of ensuring the atmosphere in the furnace, and meanwhile, the restraint of materials and components of the bottom feeding mechanism in the X-Y direction is realized by arranging the blocking block at the specific position of the bottom feeding lifting table, so that the failure rate in the lifting process is greatly reduced. According to the invention, the whole height of the bottom support guide rail is increased and the air guide holes are arranged, and the air guide arch top wall and the stirring fan are matched, so that the air in each region uniformly flows and circulates, the atmosphere at the bottom of the material tray circulates smoothly, no dead circulation occurs, the uniformity of the depth of a carburized layer of a product in the heating, carburizing and diffusing processes is ensured, and the carburizing effect is enhanced; the oil quenching tank in the oil quenching step is of a double-tank structure, one tank is filled with slow cooling oil, and the other tank is filled with fast cooling oil, so that the workpiece obtained after carburization can be subjected to more uniform and stable oil quenching, and the smoothness of the logistics of the production line is ensured.

(3) The parameters of each step are specifically set and the structural arrangement of each device is combined, so that the depth of a hardening layer of the finally obtained carburizing steel reaches 0.8-1.2 mm (550 HV 1), the surface hardness is 58-65 HRc, the whole carburizing and quenching period is relatively short, and the performance of the carburizing steel workpiece is ensured to reach the required performance on the basis of keeping the relatively short whole process treatment time.

Drawings

FIG. 1 is a schematic overall flow chart of an embodiment of the present invention.

Fig. 2 is a schematic diagram of a front cross-sectional structure of a double-row pusher tray tempering furnace according to an embodiment of the present invention.

Fig. 3 is a schematic left-view cross-sectional structure diagram of a double-row pushing-disc tempering furnace according to an embodiment of the present invention.

Fig. 4 is a schematic top sectional view of a double-row pusher tray tempering furnace according to an embodiment of the present invention.

Fig. 5 is a schematic diagram showing a sectional front view of a top wall of a heating furnace according to an embodiment of the present invention.

FIG. 6 is a schematic side sectional view of a top wall of a furnace air guide arch according to an embodiment of the present invention.

Fig. 7 is a schematic diagram showing a cross-sectional structure of a guide rail of a heating furnace according to a comparative embodiment.

Fig. 8 is a schematic view showing a cross-sectional structure of a guide rail of a heating furnace according to an embodiment of the present invention.

Reference numerals illustrate: 101-loading table, 102-front cleaning machine, 103-pre-oxidation furnace, 104-bottom feeding chamber, 105-heating zone, 106-carburizing zone, 107-carburizing zone, 108-diffusion zone, 109-quenching heat preservation chamber, 110-first oil quenching tank and second oil quenching tank, 111-double chamber cleaning device, 1111-alkali liquor cleaning chamber, 1112-clear water cleaning chamber, 112-double pushing disc tempering furnace, 113-unloading device, 201-furnace shell, 202-high temperature high pressure centrifugal fan, 203-outer air channel, 204-inner air channel, 205-heating device, 206-air guiding mechanism, 207-inner furnace wall and furnace bottom waste oil collecting device, 2071-metal baffle, 2072-oil collecting groove, 208-charging disc in tempering furnace, 209-furnace inner pushing and pulling mechanism, 210-side furnace door, 301-air guiding arch top wall, 302-charging disc in heating furnace, 303-stirring fan, 304-air guiding hole, 305-interval guide rail.

The arrows in fig. 1 are the material moving direction, and the arrows in fig. 2 are the gas flowing direction.

Detailed Description

In order to better understand the technical solution of the present invention, the following detailed description of the specific implementation method of the present invention is given with reference to the accompanying drawings and specific embodiments. The following drawings and examples are only for illustrating the present invention and do not limit the scope of the present invention. The scope of the invention is defined by the claims.

Any feature disclosed in this specification may be replaced by alternative features serving the same or equivalent purpose, unless expressly stated otherwise. Each feature is one example only of a generic series of equivalent or similar features, unless expressly stated otherwise. The description is only intended to aid in the understanding of the invention and should not be taken as limiting the invention in any way.

The drawings are for illustrative purposes only and are not to be construed as limiting the invention; for the purpose of better illustrating the embodiments, certain elements of the drawings may be omitted, enlarged or reduced and do not represent the actual product dimensions; it will be appreciated by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted; the positional relationship described in the drawings is for illustrative purposes only and is not to be construed as limiting the invention. The present invention will be described in further detail with reference to specific examples.

The invention is described in further detail below with reference to the drawings and the detailed description.

Example 1

The embodiment is to carry out specific carburization treatment on 20CrMnTiH structural steel by adopting a double-exhaust pushing-disc type controlled atmosphere carburizing and quenching method in a steel plant of Jiangsu, the whole layout is shown in figure 1, and the method comprises the following steps:

(1) And (3) feeding, namely placing the 20CrMnTiH structural steel material and the material tray on a feeding table.

(2) And (3) pre-cleaning, namely conveying the materials and the material trays which are placed on the feeding table in the step (1) into a pre-cleaning machine for pre-cleaning, wherein the temperature of a cleaning water body is 68 ℃, and performing water control operation after the pre-cleaning is finished.

(3) And (3) pre-oxidizing, namely pushing the materials and the trays after the water control operation in the step (2) into a pre-oxidizing furnace for pre-oxidizing treatment, wherein the pre-oxidizing temperature is 450 ℃, 4 trays are arranged at 5 trays of the pre-oxidizing furnace, 5 gas heating radiant tubes are arranged in total, and the installed power is 150kw (the installed power is converted power through gas heating).

(4) The bottom feeding step is carried out through a bottom feeding chamber, the bottom feeding chamber is a sealed furnace chamber, a transversely opened and closed feeding and discharging door is arranged at the bottom of the bottom feeding chamber, after the feeding and discharging door at the bottom is opened, combustible furnace gas in the furnace overflows from the lower part and burns, the burning furnace gas prevents oxygen in air from entering the bottom feeding chamber, the material and a charging tray after the pre-oxidation in the step (3) are pushed into the bottom feeding chamber, and the material and the charging tray are lifted to the track height of the heating chamber through a bottom feeding lifting table arranged in the bottom feeding chamber; and a blocking block (namely, the restriction in the X-Y direction is carried out) for blocking the horizontal displacement of the material tray and the material is arranged in the horizontal direction of the bottom feeding lifting table.

(5) And (3) heating, namely pushing the materials and trays fed from the step (4) into a heating furnace for heating, wherein the heating temperature is 920 ℃, the heating time is 20min, 9 trays are arranged at 10 trays, 10 fuel gas heating radiant tubes are arranged in total, and the installed power is 250kw.

(6) Pushing the heated material and the material trays in the step (5) to a carburizing zone for carburizing treatment, wherein the carburizing zone is set to be two zones for controlling the temperature, the carburizing temperature of the carburizing zone is set to be 930 ℃, the carbon potential is 1.1 percent CP, 8 material trays are arranged in the carburizing zone, 12 electric heating radiant tubes are arranged in total, the installed power is 130kw, and an independent temperature and carbon potential control system is arranged; the carburization temperature of the carburization two region is 950 ℃, the carbon potential is 1.0% CP, the carburization treatment time is 25min, 10 trays are arranged at 10 trays, 12 electric heating radiant tubes are arranged in total, the installed power is 125-135 kw, and an independent temperature and carbon potential control system is arranged.

(7) And (3) diffusing, namely pushing the material and the tray subjected to carburization in the step (6) to a diffusion area for diffusing and homogenizing, wherein the heat preservation temperature is 930 ℃, the carbon potential is 0.9% CP, the heat preservation time is 23min, 10 tray positions and 9 trays are arranged, 12 electric heating radiant tubes are arranged in total, the installed power is 90kw, and an independent temperature and carbon potential control system is arranged.

The steps (5) to (7) are completed in a partition through type hearth, as shown in fig. 5 and 6, air guide arch top walls are arranged between the partition through areas in the hearth, the tops of the air guide arch top walls are connected with the arch at the top of the hearth, openings are formed in the passing positions of a charging tray and a guide rail, a stirring fan is arranged at the top of each area and is used for stirring the gas in the area, and the uniformity of the furnace gas and the furnace temperature in the main body of each area is realized; three rows of guide rails are arranged at the bottom in the partition through type hearth, the distance between the top ends of the guide rails of the heating furnace and the inner wall of the hearth is 674mm, the height of the charging tray is 740mm, the proportion of the two is 0.905, the proportion is in the range of 0.98-0.89, and as shown in fig. 8, air guide holes which transversely penetrate through the two ends of the guide rails are formed in the guide rails and the partition guide rails.

(8) And (3) cooling and preserving heat, namely pushing the materials and trays subjected to diffusion treatment in the step (7) into a quenching and preserving heat chamber for preserving heat, wherein the preserving heat temperature is 820 ℃, the carbon potential is 0.8% CP, the preserving heat time is 21min, 7 tray positions and 6 trays are arranged, 12 electric heating radiant tubes are arranged in total, the installed power is 130kw, and the independent temperature and carbon potential control system is arranged.

(9) Transferring the materials and the material trays subjected to cooling and heat preservation in the step (8) into a first oil quenching tank, and carrying out oil quenching in the first oil quenching tank, wherein the temperature of quenching oil in the first oil quenching tank is 60 ℃, and the oil quenching time in the first oil quenching tank is 10min; and transferring the materials and the material trays to a second oil quenching tank, carrying out oil quenching in the second oil quenching tank, wherein the temperature of quenching oil in the second oil quenching tank is 120 ℃, the oil quenching time in the second oil quenching tank is 9min, then lifting the materials and the material trays from the second oil quenching tank, and controlling oil on a conveying roller way for 20min.

(10) And (3) after-cleaning, conveying the materials and the material trays after oil control in the step (9) into a double-chamber cleaning device, firstly entering an alkali liquor cleaning chamber, after soaking in alkali liquor for 9min, then discharging alkali liquor for alkali liquor spray cleaning, wherein the alkali liquor temperature is 80 ℃, the alkali liquor spray cleaning time is 8min, conveying the materials and the material trays into a clear water cleaning chamber, cleaning the materials in the clear water cleaning chamber through spraying, and the clear water temperature is 70 ℃ and the clear water cleaning time in the clear water cleaning chamber is 19min.

(11) And (3) tempering, namely conveying the materials and the trays obtained after the cleaning treatment in the step (10) to a double-row pushing tray tempering furnace for tempering and heat preservation, alternately pushing the materials and the trays in the double-row pushing tray tempering furnace to advance through double main pushing (namely alternately pushing the materials onto two guide rails from one guide rail respectively, so that the trays between the adjacent guide rails are not adjacent and are spaced, alternately discharging during discharging, and conveying the materials on the two guide rails onto one guide rail), wherein the tempering and heat preservation temperature is 180 ℃, the heat preservation time is 380min, pushing the materials and the trays through a pushing chain mechanism, and performing air cooling and cooling to realize cooling treatment after tempering.

(12) And (3) unloading, namely unloading the material subjected to tempering in the step (11) through an unloading device to finish the controlled atmosphere carburizing and quenching treatment of the material.

Example 2

The embodiment is used for showing the tempering furnace used in the step (11) of the embodiment 1, and as shown in fig. 2-4, the double-row pushing disc tempering furnace comprises a high-temperature and high-pressure resistant centrifugal fan, an outer air duct, a furnace shell, an inner air duct, a heating device, a wind guiding mechanism, an inner furnace wall and furnace bottom waste oil collecting device, an in-furnace pushing and pulling mechanism, a side furnace door and a furnace door sealing mechanism.

The inner air channel is arranged at the inner top of the furnace shell, and a heating device is arranged in the inner air channel and is of a rod-shaped structure penetrating through the furnace shell; the inner air duct discharges hot air into the hearth through the air guide mechanism.

The inlet end of the outer air channel is communicated with the inner wall of the front end of the furnace shell, the exhaust end of the outer air channel is communicated with the top of the inner wall of the rear end of the furnace shell, the high-temperature and high-pressure resistant centrifugal fan is arranged on the outer air channel, and the high-temperature and high-pressure resistant centrifugal fan sucks hot air at 165-198 ℃ from the hearth through the inlet end of the outer air channel and then discharges the hot air back into the inner air channel through the rear end of the outer air channel and the top of the furnace shell.

The air guide mechanism is an inclined straight plate or arc plate, one part of the straight plate or arc plate is arranged at the outlet of the inner air channel, one end of the straight plate or arc plate is connected with the inner side wall of the furnace shell, the other end of the straight plate or arc plate is inclined downwards, heated hot air is guided from the inner air channel towards the hearth in the directions of materials and the charging trays, the other part of the straight plate or arc plate is arranged below the inlet end of the outer air channel, one end of the straight plate or arc plate is connected with the inner side wall of the furnace shell, and the other end of the straight plate or arc plate is inclined downwards, so that the heated air in the hearth is guided from the hearth towards the direction of the inlet end of the outer air channel.

The waste oil collecting device for the inner furnace wall and the furnace bottom comprises a metal baffle plate and an oil collecting groove, wherein the metal baffle plate is arranged at the inner side wall and the inner top wall of the furnace shell, the metal baffle plate arranged at the inner top wall is connected with the metal baffle plate arranged at the inner side wall, the bottom end of the metal baffle plate arranged at the inner side wall is connected with the oil collecting groove, and the oil collecting groove is arranged at the furnace bottom and is connected with the metal baffle plate arranged at the inner side wall by a chamfer angle of 5-10 degrees (the chamfer angle of 6 degrees in the embodiment).

The push-pull mechanism in the furnace comprises two rails and two push-pull parts, wherein the push-pull parts are respectively arranged on the two rails and are used for moving the material trays and the materials on the rails.

The side furnace door is provided with two sets of furnace shell side parts which are respectively arranged at the initial end and the final end of the track; the furnace door sealing mechanism is used for sealing the side furnace door.

Comparative example 1

This comparative example was used to show the results of a comparative experiment in which the double-row pusher tray tempering furnace of the present invention was not used, but instead, an existing conventional pusher tray tempering furnace (without double-row rails for alternate distribution, and without external air ducts and internal furnace wall and furnace bottom waste oil collecting means) was provided, and the other arrangement was exactly the same as in example 1. After carburizing the same workpiece as in example 1, the workpieces obtained in example 1 and comparative example 1 were examined to obtain the workpiece of example 1 having a surface hardness of 62.9HRc and the workpiece of comparative example 1 having a surface hardness of 60.2HRc. Since other arrangement modes are the same as those of the embodiment 1, the tempering effect is reduced due to different arrangement of the tempering furnace, and the double-row pushing-disc tempering furnace provided by the invention ensures even and stable tempering through arrangement of parts such as an air duct and the like, so that the tempering effect is ensured.

Comparative example 2

In the comparative example, in the step (4), the air in the bottom feeding chamber is firstly exhausted by adopting inert gas, and then the feeding is carried out under the protection of the inert gas, other setting modes are exactly the same as those of the embodiment 1 and the embodiment 2, and the detection is carried out on the workpieces obtained in the embodiment 1 and the comparative example 2, so that the parameters such as the hardening layer depth and the surface hardness of the carburizing steel of the workpieces in the embodiment 1 and the comparative example 2 are basically consistent, namely the products with the same performance can be basically obtained in the embodiment 2 and the embodiment 1 and the embodiment 2, but the cost is greatly increased due to the continuous use of the inert gas, and the invention reduces the production cost by feeding in a mode that the flammable furnace gas overflows from the lower part and burns, under the condition that the performance of the products is unchanged.

Comparative example 3

The carbon potential of the comparative example in the carburized first zone, the carburized second zone and the quenching heat-preserving chamber is kept at 0.9% CP, the carbon potential of the diffusion zone and the quenching heat-preserving chamber is kept at 0.7% CP, other setting modes are completely consistent with those of the examples 1 and 2, the workpieces obtained in the example 1 (adopting the tempering furnace of the example 2) and the comparative example 3 are detected, the carburized hardening layer depth of the workpiece of the example 1 reaches 1.11mm (the vertical distance from the surface of the workpiece to the position with the Vickers hardness value of 550HV is the depth of the carburized layer), and the carburized steel hardening layer depth of the workpiece of the comparative example 1 is 1.03mm, namely, under the condition that the other conditions are kept the same, the carbon potential is changed only in different zones, the degradation of the depth of the carburized layer is caused, so that the temperature and the carbon potential of each zone and the specific setting mode of each zone are in close coordination are proved, the change of the carbon potential is only one factor, the bad effect is caused, and the close coordination among all parameters is proved.

Comparative example 4

In this comparative example, no air guide holes were provided in the guide rail and the spacing guide rail of the heating furnace, and the other arrangement was exactly the same as in example 1 and example 2.

Comparative example 5

In this comparison, for example, as shown in fig. 7, no air guide holes are provided in the spaced guide rails, and the other arrangement is exactly the same as that of embodiment 1 and embodiment 2. The surface hardness test was conducted on the carburized products produced in comparative examples 4 and 5, and it was found that in the case where the other parameters were exactly the same as those of example 1 and example 2, 5 spots were each detected (5 spots of example 1 were each within a range of 1.11 mm.+ -. 0.05 mm), 1 spot had a carburized layer depth of 1.11 mm.+ -. 0.01mm, the carburized layer depths of the other 4 spots of comparative example 4 were distributed between 1.01 and 1.09mm, and the carburized layer depths of the other 4 spots of comparative example 5 were distributed between 1.03 and 1.13mm, and were uniformly distributed, because although the depths were within a certain error range, example 1 was smoothly circulated in the air temperature in the heating furnace, whereas in example 1 shown in fig. 7, hot air on the right side or left side of comparative example 5 could only be moved upward when circulated to the lower portion of the rail, whereas in example 1 shown in fig. 8, hot air could pass through the air guide holes in the lower portion of the rail, so that heat was not accumulated at the side portion.

Finally, it should be noted that: the above examples are only for illustrating the technical scheme of the present invention, but not for limiting the same, the invention points without comparison are not subjected to comparison test, and cannot illustrate the height thereof, but the height thereof can be proved by the text part; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. The double-row fuel gas pushing disc type controlled atmosphere carburizing and quenching method is characterized by comprising the following steps of:

(1) Feeding, namely placing materials and a material tray on a feeding table; the material is alloy structural steel capable of being carburized;

(2) The material and the tray which are placed on the feeding table in the step (1) are conveyed into a front cleaning machine for front cleaning, the temperature of cleaning liquid is 50-80 ℃, and standing water control operation is carried out after the front cleaning is finished;

(3) Pre-oxidizing, namely pushing the materials and the material trays subjected to the water control operation in the step (2) into a pre-oxidizing furnace for pre-oxidizing treatment, wherein the pre-oxidizing temperature is 350-550 ℃;

(4) The bottom feeding step is carried out through a bottom feeding chamber, the bottom feeding chamber is a sealed furnace chamber, a transversely opened and closed feeding and discharging door is arranged at the bottom of the bottom feeding chamber, after the feeding and discharging door at the bottom is opened, combustible furnace gas in the furnace overflows from the lower part and burns, the burning furnace gas prevents oxygen in air from entering the bottom feeding chamber, the material and a charging tray after the pre-oxidation in the step (3) are pushed into the bottom feeding chamber, and the material and the charging tray are lifted to the track height of the heating chamber through a bottom feeding lifting table arranged in the bottom feeding chamber; a blocking block for blocking the horizontal displacement of the material tray and the material is arranged in the horizontal direction of the bottom feeding lifting table;

(5) Heating, namely pushing the materials and the material trays fed from the bottom of the step (4) into a heating zone of a heating furnace for heating, wherein the heating temperature is 800-950 ℃, and the heating time is 15-30 min;

(6) Pushing the heated material and the heated material tray in the step (5) to a carburizing zone for carburizing treatment, wherein the carburizing zone is set to be two zones, the temperature of the first carburizing zone is set to be 830-950 ℃, the carbon potential is (1.05-1.11)% CP, the temperature of the second carburizing zone is 850-960 ℃, the carbon potential is (0.96-1.03)% CP, and the carburizing treatment time is in the range of 15-30 min;

(7) Diffusing, namely pushing the material and the material tray subjected to carburization in the step (6) to a diffusion area for diffusing and homogenizing, wherein the temperature is 830-980 ℃, the carbon potential is (0.85-0.95)% CP, and the temperature keeping time is 15-30 min;

(8) Cooling and preserving heat, pushing the material and the material tray subjected to the diffusion treatment in the step (7) into a quenching and preserving heat chamber for preserving heat, wherein the preserving heat temperature is 790-860 ℃, the carbon potential is (0.76-0.85)% CP, and the preserving heat time is 15-30 min;

(9) Transferring the materials and the material trays subjected to temperature reduction and heat preservation in the step (8) into a first oil quenching tank, and carrying out oil quenching in the first oil quenching tank, wherein the temperature of quenching oil in the first oil quenching tank is 50-69 ℃, and the cooling time of the oil quenching in the first oil quenching tank is 8-12 min; transferring the material and the material tray subjected to oil quenching in the first tank into a second oil quenching tank which is arranged, or directly transferring the material and the material tray subjected to cooling and heat preservation in the step (8) into a preset second oil quenching tank, and performing oil quenching in the second oil quenching tank, wherein the temperature of quenching oil in the second oil quenching tank is 110-128 ℃, and the cooling time of the oil quenching in the second oil quenching tank is 8-12 min; after quenching is finished, the materials and the material trays are lifted out of the first oil quenching tank and/or the second oil quenching tank, and oil is controlled on a conveying roller way for 15-30 min;

(10) After-cleaning, conveying the materials and the material trays after oil control in the step (9) into a double-chamber cleaning device, firstly entering an alkali liquor cleaning chamber, after soaking in alkali liquor for 8-15 min, discharging alkali liquor for alkali liquor spray cleaning, wherein the alkali liquor temperature is 62-82 ℃, the alkali liquor spray cleaning time is 7-15 min, conveying the materials and the material trays into a clean water cleaning chamber, carrying out spray cleaning on the materials in the clean water cleaning chamber in a spray manner, and the clean water temperature of clean water is 58-76 ℃ and the clean water cleaning time in the clean water cleaning chamber is 15-30 min;

(11) Tempering, namely conveying the materials and the trays obtained after the cleaning treatment in the step (10) into a double-row pushing tray tempering furnace for tempering and heat preservation, alternately pushing the trays in the double-row pushing tray tempering furnace to advance through double main pushing, wherein the tempering and heat preservation temperature is 165-198 ℃, the heat preservation time is 270-540 min, pushing the materials and the trays out through a pushing chain mechanism, and performing air cooling and cooling;

(12) And (3) unloading, namely unloading the material subjected to tempering in the step (11) to finish the controlled atmosphere carburizing and quenching treatment of the material.

2. The dual-exhaust gas pusher-disc controlled atmosphere carburizing and quenching method according to claim 1, wherein the alloy structural steel in step (1) is one or more of 20CrMnTiH, 20CrMoH, SCM420H, 20MnCr5H or SAE 8620H.

3. The double-row gas pushing disc type controlled atmosphere carburizing and quenching method according to claim 1, wherein the double-row pushing disc type tempering furnace used in the step (11) comprises a high-temperature and high-pressure resistant centrifugal fan, an outer air channel, a furnace shell, an inner air channel, a heating device, a wind guiding mechanism, an inner furnace wall and furnace bottom waste oil collecting device, an in-furnace pushing and pulling mechanism, a side furnace door and a furnace door sealing mechanism;

the inner air channel is arranged at the inner top of the furnace shell, and a heating device is arranged in the inner air channel and is of a rod-shaped structure penetrating through the furnace shell; the inner air duct discharges hot air into the hearth through the air guide mechanism;

the inlet end of the outer air channel is communicated with the inner wall of the front end of the furnace shell, the exhaust end of the outer air channel is communicated with the top of the inner wall of the rear end of the furnace shell, the high-temperature and high-pressure resistant centrifugal fan is arranged on the outer air channel, and the high-temperature and high-pressure resistant centrifugal fan sucks hot air at 165-198 ℃ from the hearth through the inlet end of the outer air channel and then discharges the hot air back into the inner air channel through the rear end of the outer air channel and the top of the furnace shell;

the air guide mechanism is an inclined straight plate or an arc plate, one part of the straight plate or the arc plate is arranged at the outlet of the inner air channel, one end of the straight plate or the arc plate is connected with the inner side wall of the furnace shell, the other end of the straight plate or the arc plate is inclined downwards, heated hot air is guided from the inner air channel to the hearth in the directions of materials and the material tray, the other part of the straight plate or the arc plate is arranged below the inlet end of the outer air channel, one end of the straight plate or the arc plate is connected with the inner side wall of the furnace shell, and the other end of the straight plate or the arc plate is inclined downwards, so that the hot air in the hearth is guided from the hearth to the direction of the inlet end of the outer air channel;

the waste oil collecting device of the inner furnace wall and the furnace bottom comprises a metal baffle plate and an oil collecting groove, wherein the metal baffle plate is arranged at the inner side wall and the inner top wall of the furnace shell, the metal baffle plate arranged at the inner top wall is connected with the metal baffle plate arranged at the inner side wall, the bottom end of the metal baffle plate arranged at the inner side wall is connected with the oil collecting groove, and the oil collecting groove is arranged at the furnace bottom and is connected with the metal baffle plate arranged at the inner side wall by a chamfer angle of 5-10 degrees;

the in-furnace pushing and pulling mechanism comprises two rails and two pushing and pulling parts, wherein the pushing and pulling parts are respectively arranged on the two rails and are used for moving a tray and materials on the rails;

the side furnace door is provided with two sets of furnace shell side parts which are respectively arranged at the initial end and the final end of the track; the furnace door sealing mechanism is used for sealing the side furnace door.

4. The dual-exhaust gas pusher tray type controlled atmosphere carburizing and quenching method according to claim 3, wherein the furnace door sealing mechanism is a high temperature resistant fiber strip.

5. The double-row fuel gas push-disc type controlled atmosphere carburizing and quenching method according to claim 1, wherein the pre-oxidizing furnace in the step (3) is provided with 5 material disc positions and 4 disc materials, 5 fuel gas heating radiant tubes are arranged in total, and the installed power is 145-155 kw.

6. The double-row fuel gas push-plate type controlled atmosphere carburizing and quenching method according to claim 1, wherein the steps (5) to (7) are completed in a zoned through hearth, air guide arch top walls are arranged between zones which are communicated in the hearth, the tops of the air guide arch top walls are connected with the arch of the top of the hearth, openings are formed in the passing positions of a material plate and a guide rail, a stirring fan is arranged at the top of each zone, and the stirring fan is used for stirring the gas in the zone to realize the main uniformity of furnace gas and furnace temperature in each zone; the bottom in the partition through type hearth is provided with a plurality of rows of guide rails, the ratio of the distance between the top ends of the guide rails and the inner wall of the hearth to the height of the material tray is 0.89-0.98, and the guide rails and the interval guide rails are provided with air guide holes which are transverse and penetrate through the two ends of the guide rails.

7. The double-row fuel gas push-disc type controlled atmosphere carburizing and quenching method is characterized in that the steps (5) to (7) are completed in a zoned through hearth, wherein zone I is a heating zone, 10 material disc positions and 9 disc materials are arranged in the heating zone, 10 fuel gas heating radiant tubes are arranged in total, the installed power is 235-258 kw, and the heating zone is independently temperature controlled; the II area is a carburizing area, is provided with 8 material tray positions and 8 trays, is provided with 12 electric heating radiant tubes in total, has the installed power of 125-135 kw, and is provided with independent temperature and carbon potential control components; the III area is a carburization two-area, is provided with 10 material tray positions and 10 trays, is provided with 12 electric heating radiant tubes in total, has the installed power of 125-135 kw, and is provided with independent temperature and carbon potential control components; the IV area is a diffusion area, is provided with 10 material tray positions and 9 trays, is totally provided with 12 electric heating radiant tubes, has the installed power of 85-95 kw, and is provided with independent temperature and carbon potential control components.

8. The dual-exhaust gas pusher tray type controlled atmosphere carburizing and quenching method according to claim 6, wherein the plurality of rows of guide rails arranged at the bottom in the partition through type hearth are three rows, and the guide rails are silicon carbide guide rails.

9. The double-row gas push-disc type controlled atmosphere carburizing and quenching method according to claim 1, wherein the quenching and heat preservation chamber in the step (8) is provided with 7 material disc positions and 6 material discs, 12 electric heating radiant tubes are arranged in total, the installed power is 125-135 kw, and the quenching and heat preservation chamber is provided with independent temperature and carbon potential control components.

10. The double-row gas pushing disc type controllable atmosphere carburizing and quenching method is characterized in that the double-chamber cleaning device in the step (10) is of a double-chamber structure, the first chamber is an alkali liquor cleaning chamber, an alkali water tank is arranged in the alkali liquor cleaning chamber, a main heating component is carried out on tank liquor in the alkali water tank by adopting an exhaust gas combustion waste heat utilization device, 6 electric heating pipes are simultaneously arranged as spare auxiliary heating components, and the electric heating pipes are 30-40 kw; the second chamber is a clean water cleaning chamber, a clean water tank is arranged in the clean water cleaning chamber, the tank liquor of the clean water tank adopts an exhaust gas combustion waste heat utilization device to carry out main heating parts, 4 electric heating pipes are arranged as auxiliary heating parts for standby, and the electric heating pipes are 20-28 kw.