CN112359178A - Heat treatment process for steel workpiece - Google Patents
Heat treatment process for steel workpiece Download PDFInfo
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- CN112359178A CN112359178A CN202011142851.1A CN202011142851A CN112359178A CN 112359178 A CN112359178 A CN 112359178A CN 202011142851 A CN202011142851 A CN 202011142851A CN 112359178 A CN112359178 A CN 112359178A
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
- C21D1/28—Normalising
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/34—Methods of heating
- C21D1/44—Methods of heating in heat-treatment baths
- C21D1/46—Salt baths
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/02—Pretreatment of the material to be coated
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
- C23C8/20—Carburising
- C23C8/22—Carburising of ferrous surfaces
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/80—After-treatment
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/002—Bainite
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/009—Pearlite
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- Mechanical Engineering (AREA)
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- Organic Chemistry (AREA)
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- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
A heat treatment process of a steel workpiece comprises the following steps: s1, normalizing: s11 normalizing; s12 air cooling: taking the steel workpiece after the normalizing heat treatment out of the furnace, and air-cooling until the surface temperature of the steel workpiece is reduced to 600-650 ℃; s13 heat preservation treatment: returning the steel workpiece to the furnace to raise the temperature in the furnace; repeating the step S12 when the temperature in the furnace is higher than 700 ℃; when the final temperature in the furnace is 675-690 ℃, executing S14; s14, cooling along with the furnace; s2, carburizing: s21 forced osmosis treatment: transferring the workpiece treated by the S1 into a carburizing furnace, heating to 900-930 ℃ and carrying out strong permeation treatment for 4.5-5.5 h; s22 diffusion processing: after the strong cementation treatment is finished, keeping the temperature of the carburizing furnace unchanged, reducing the carbon potential of the workpiece to a preset diffusion carbon potential, and starting diffusion treatment for 5.5-7 hours; s23 temperature equalization treatment; s24 high-temperature tempering; s3, quenching; and S4, low-temperature tempering. The heat treatment process of the steel workpiece utilizes the self waste heat after the steel workpiece is normalized to carry out heat preservation treatment, and the energy consumption is reduced by about one third; and the phenomenon of peeling of a carburized layer is avoided, and the quality of the workpiece is good.
Description
Technical Field
The invention relates to the technical field of heat treatment, in particular to a heat treatment process of a steel workpiece.
Background
The heat treatment is a metal hot processing technology for changing the chemical components and structures on the surface or in the material to obtain the required performance by heating, heat preservation and cooling the metal material in a solid state.
The steel workpiece is generally treated by working procedures of normalizing, carburizing, quenching and the like in the heat treatment process, and most of the prior normalizing treatment working procedures cool the workpiece to room temperature first and then heat and temper the workpiece, so that the energy consumption is high, the process period is long and the operation is complex; secondly, the strong cementation time in the carburization process is generally longer than that of diffusion treatment, so that the phenomenon that a carburized layer peels off occurs in the use process of the steel workpiece at present, along with the improvement of social energy-saving and environment-friendly requirements and the high requirements of special fields such as drilling and the like on the quality and the service life of the steel workpiece, therefore, the improvement of the heat treatment process of the existing steel workpiece is urgently needed, so that the energy consumption in the heat treatment process is reduced, the distribution gradient of the carbon concentration on the surface layer of the steel workpiece is effectively slowed down, the quality of the steel workpiece product is improved, and the requirements of the market on energy conservation and consumption reduction are met.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: overcomes the defects of the prior art, and provides a heat treatment process of a steel workpiece, which is simple to operate, low in energy consumption and slow in the carbon concentration distribution gradient of the surface layer of the product.
The technical scheme adopted by the invention for solving the technical problems is as follows:
a heat treatment process of a steel workpiece comprises the following steps:
s1, normalizing:
s11 normalizing: putting a steel workpiece to be processed into an electric furnace, heating to 880 +/-10 ℃, and preserving heat for 6-9 hours;
s12 air cooling: taking the steel workpiece after the normalizing heat treatment out of the furnace, and air-cooling until the surface temperature of the steel workpiece is reduced to 600-650 ℃;
s13 heat preservation treatment: feeding the steel workpiece into an electric furnace, closing a furnace door, continuously dissipating the temperature of a core part of the steel workpiece, preserving the temperature of the steel workpiece by utilizing the self waste heat, and raising the temperature in the furnace;
repeating the step S12 when the temperature in the furnace is higher than 700 ℃;
when the final temperature in the furnace is 675-690 ℃, executing S14;
s14 furnace cooling: naturally cooling the steel workpiece in the furnace along with the furnace;
s2, carburizing:
s21 forced osmosis treatment: transferring the workpiece treated by the S1 into a carburizing furnace, heating to 900-930 ℃ and carrying out strong permeation treatment for 4.5-5.5 h;
s22 diffusion processing: after the strong cementation treatment is finished, keeping the temperature of the carburizing furnace unchanged, reducing the carbon potential of the workpiece to a preset diffusion carbon potential, and starting diffusion treatment for 5.5-7 hours;
s23 temperature equalization treatment: cooling a heating chamber of the carburizing furnace to 850 +/-10 ℃, preserving heat for 50-75 min, transferring the workpiece to a front chamber of the carburizing furnace, slowly cooling for 2-2.5 h, and then discharging the workpiece out of the furnace for air cooling;
s24 high-temperature tempering: sending the workpiece which is air-cooled to 50-70 ℃ into a tempering furnace, tempering at the high temperature of 680 +/-10 ℃ for 5-6 h, then cooling to 580 ℃ along with the furnace, taking out the workpiece from the furnace, and putting the workpiece into a slow cooling tank for slow cooling;
s3, quenching: heating the steel workpiece to 830 +/-10 ℃, preserving heat for 25-35 minutes, then quickly taking out, putting into a low-temperature nitrate furnace, keeping for 25-40 minutes, and then taking out;
s4, low-temperature tempering: heating the steel workpiece to 180-200 +/-10 ℃, keeping the temperature for 4-5 hours, taking out and air-cooling.
Wherein the temperature rising speed of the electric furnace in S11 for heating to the normalizing temperature is more than or equal to 100 ℃/h
The specific operation of S14 furnace cooling is as follows: and naturally cooling the steel workpiece in the furnace to below 550 ℃, taking out the steel workpiece from the furnace, and air-cooling to room temperature.
In an exemplary embodiment, in S12, the steel workpiece is air-cooled until the surface temperature of the steel workpiece is reduced to 640-650 ℃, and the surface temperature of the steel workpiece is monitored by an infrared thermometer.
Before S21, the steel workpiece processed by S1 needs to be preprocessed, and the specific operations are as follows: putting the workpiece on a special material rack, putting the workpiece in a cleaning furnace, cleaning the workpiece for 5-6 minutes by using cleaning fluid at 85-90 ℃, and cleaning oil stains and dust on the surface of the workpiece; and transferring the cleaned workpiece into a tempering furnace, and drying and preheating at the temperature of 410 +/-10 ℃ for 30-45 minutes.
The carbon potential of the S21 strong penetration treatment is 0.98-1.03, and the carbon potential of the S22 diffusion treatment is 0.63-0.68.
The carburizing agent adopted in the S21 strong carburizing treatment and the S22 diffusion treatment is propane, methanol is adopted as a diluent, the carbon potential level is controlled by adjusting the flow rate of propane and methanol introduced into the carburizing furnace, the carbon potential level is detected by an infrared ray or an oxygen probe, and the temperature is controlled by a thermocouple.
In an exemplary embodiment, prior to S1, a forging process is performed on the steel workpiece to be machined; after the step of S1, machining treatment of one or more of rough turning, finish turning, drilling, spline milling and burr removing is needed;
after S2 and before S3, the method also comprises the treatment procedures of carbon layer removal and slag discharge groove milling for the steel workpiece,
the steel workpiece is steel for drilling tools, and the material of the steel workpiece is 23CrNi3 MoA.
The heat treatment process of the steel workpiece has the beneficial effects that:
1) compared with the conventional method, the steel workpiece after normalizing treatment is air-cooled to room temperature and then tempered, and the heat preservation treatment is carried out by utilizing the self waste heat after the steel workpiece is normalized, so that the energy consumption is reduced by about one third.
2) After the normalizing, the steel workpiece with the surface temperature cooled to 600-650 ℃ is taken out of the heating furnace, the temperature difference between the core part temperature and the surface temperature is about 150 ℃, then the steel workpiece is returned to the electric furnace for sealing and heat preservation, the temperature in the furnace can be raised to about 680-720 ℃ by the heat of the core part of the steel workpiece, the formation of the pearlite metallographic structure in the steel workpiece is facilitated, the hardness of the steel workpiece is further changed, and the subsequent processing of the steel workpiece is facilitated.
3) After the normalizing treatment of the steel workpiece, the metallographic structure of the steel workpiece is fine lamellar pearlite, a small amount of upper bainite and ferrite, the grain size grade is 8, the hardness is HRC18-20, and the hardness is relatively lower than that of the steel workpiece subjected to the heat treatment by combining the conventional normalizing with high-temperature tempering (the hardness of the steel workpiece subjected to the normalizing heat treatment is HRC 25-27).
4) The invention reduces the number of active carbon atoms by shortening the strong cementation treatment time, thereby properly reducing the carbon concentration of a carburized layer; the diffusion treatment time is prolonged, so that the high carbon concentration on the surface of the workpiece is fully diffused inwards to obtain a carbon concentration gradient with slower distribution, the phenomenon of peeling of a carburized layer is avoided, and the quality of the workpiece is greatly improved; and then high-temperature tempering treatment at 680 +/-10 ℃ is carried out, so that cementite on the metal surface of the carburized part is spheroidized, the carbon content in austenite is reduced after quenching, the austenite is easily converted into quenched martensite, the content of the retained austenite of the structure is reduced, the cracking risk of the workpiece in the use process is reduced, and the service life of the workpiece is prolonged. The high-temperature tempering is favorable for the unmelted cementite to exist in the form of dispersed granular carbide, so that the metallographic structure is improved, and the surface hardness of a carburized part is effectively improved.
Detailed Description
The present invention is further illustrated by the following examples.
Comparative example
The heat treatment process of the steel workpiece in the prior art is adopted, the steel workpiece is steel for drilling tools, the material of the steel workpiece is 23CrNi3MoA, and the heat treatment process comprises the following specific steps:
blanking is carried out according to the steel workpiece to be processed, and then forging treatment is carried out on the steel workpiece to be processed;
s1, normalizing:
s11 normalizing: putting a steel workpiece to be processed into an electric furnace, heating the electric furnace to 870 +/-10 ℃ at the heating rate of 145 ℃/h, and preserving heat for 9 hours;
s12 air cooling: taking the steel workpiece after the normalizing heat treatment out of the furnace, and cooling the steel workpiece to room temperature by air cooling;
s13 heat preservation treatment: feeding the steel workpiece into an electric furnace, closing a furnace door, heating to raise the temperature in the furnace to 700 +/-10 ℃, and carrying out heat preservation treatment;
s14 furnace cooling: naturally cooling the steel workpiece in the furnace to below 550 ℃, taking out the steel workpiece from the furnace, and air-cooling to room temperature;
carrying out machining treatment in rough turning, finish turning, drilling, spline milling and burr removing on the steel workpiece subjected to the normalizing treatment of S1 in sequence; then putting the workpiece on a special material rack, putting the workpiece in a cleaning furnace, cleaning the workpiece for 5-6 minutes by using cleaning fluid at 85-90 ℃, and cleaning oil stains and dust on the surface of the workpiece; transferring the cleaned workpiece into a tempering furnace, keeping the temperature at 410 +/-10 ℃ for 30-45 minutes, drying and preheating, and performing S2 carburizing treatment;
s2, carburizing:
s21 forced osmosis treatment: transferring the workpiece processed by the S1 into a carburizing furnace, heating to 920 +/-5 ℃ and carrying out strong infiltration treatment for 6 h;
s22 diffusion processing: after the strong cementation treatment is finished, keeping the temperature of the carburizing furnace unchanged, reducing the carbon potential of the workpiece to a preset diffusion carbon potential, and starting diffusion treatment for 5 hours;
s23 temperature equalization treatment: cooling a heating chamber of the carburizing furnace to 850 +/-10 ℃, preserving heat for 60min, transferring the workpiece to a front chamber of the carburizing furnace, slowly cooling for 2h, discharging and air cooling;
s24 high-temperature tempering: sending the workpiece which is air-cooled to 50-70 ℃ into a tempering furnace, tempering at the high temperature of 680 +/-10 ℃ for 6 hours, then cooling to 580 ℃ along with the furnace, discharging and putting into a slow cooling tank for slow cooling;
s3, quenching: heating the steel workpiece to 830 +/-10 ℃, preserving heat for 25-35 minutes, then quickly taking out, putting into a low-temperature nitrate furnace, keeping for 25-40 minutes, and then taking out;
s4, low-temperature tempering: heating the steel workpiece to 200 +/-10 ℃, keeping the temperature for 5 hours, taking out and air-cooling.
The carbon potential of the S21 strongly cementation treatment was 0.98, and the carbon potential of the S22 diffusion treatment was 0.68.
Example 1
In the heat treatment process of the steel workpiece in this embodiment, the steel workpiece is steel for a drilling tool, and the material of the steel workpiece is 23CrNi3MoA, and the heat treatment process includes the following steps:
blanking is carried out according to the steel workpiece to be processed, and then forging treatment is carried out on the steel workpiece to be processed;
s1, normalizing:
s11 normalizing: putting a steel workpiece to be processed into an electric furnace, heating the electric furnace to 870 +/-10 ℃ at the heating rate of 145 ℃/h, and preserving heat for 9 hours;
s12 air cooling: taking the steel workpiece after the normalizing heat treatment out of the furnace, and air-cooling until the surface temperature of the steel workpiece is reduced to 620 +/-10 ℃;
s13 heat preservation treatment: feeding the steel workpiece into an electric furnace, closing a furnace door, continuously dissipating the temperature of a core part of the steel workpiece, preserving the temperature of the steel workpiece by utilizing the self waste heat, and raising the temperature in the furnace;
repeating the step S12 when the temperature in the furnace is higher than 700 ℃;
when the final temperature in the furnace is 680 ℃, performing S14;
s14 furnace cooling: naturally cooling the steel workpiece in the furnace to below 550 ℃, taking out the steel workpiece from the furnace, and air-cooling to room temperature;
carrying out machining treatment in rough turning, finish turning, drilling, spline milling and burr removing on the steel workpiece subjected to the normalizing treatment of S1 in sequence; then putting the workpiece on a special material rack, putting the workpiece in a cleaning furnace, cleaning the workpiece for 5-6 minutes by using cleaning fluid at 85-90 ℃, and cleaning oil stains and dust on the surface of the workpiece; transferring the cleaned workpiece into a tempering furnace, keeping the temperature at 410 +/-10 ℃ for 30-45 minutes, drying and preheating, and performing S2 carburizing treatment;
s2, carburizing:
s21 forced osmosis treatment: transferring the workpiece processed by the S1 into a carburizing furnace, heating to 920 +/-5 ℃ and carrying out strong permeation treatment for 5 hours;
s22 diffusion processing: after the strong cementation treatment is finished, keeping the temperature of the carburizing furnace unchanged, reducing the carbon potential of the workpiece to a preset diffusion carbon potential, and starting diffusion treatment for 6 hours;
s23 temperature equalization treatment: cooling a heating chamber of the carburizing furnace to 850 +/-10 ℃, preserving heat for 60min, transferring the workpiece to a front chamber of the carburizing furnace, slowly cooling for 2h, discharging and air cooling;
s24 high-temperature tempering: sending the workpiece which is air-cooled to 50-70 ℃ into a tempering furnace, tempering at the high temperature of 680 +/-10 ℃ for 6 hours, then cooling to 580 ℃ along with the furnace, discharging and putting into a slow cooling tank for slow cooling;
s3, quenching: heating the steel workpiece to 830 +/-10 ℃, preserving heat for 25-35 minutes, then quickly taking out, putting into a low-temperature nitrate furnace, keeping for 25-40 minutes, and then taking out;
s4, low-temperature tempering: heating the steel workpiece to 200 +/-10 ℃, keeping the temperature for 5 hours, taking out and air-cooling.
In S12, the surface temperature of the steel workpiece is monitored by an infrared thermometer.
The carbon potential of the S21 strongly cementation treatment was 0.98, and the carbon potential of the S22 diffusion treatment was 0.68.
The carburizing agent adopted in the S21 strong carburizing treatment and the S22 diffusion treatment is propane, methanol is adopted as a diluent, the carbon potential level is controlled by adjusting the flow rate of propane and methanol introduced into the carburizing furnace, the carbon potential level is detected by an infrared ray or an oxygen probe, and the temperature is controlled by a thermocouple.
After S2 and before S3, the method also comprises the treatment procedures of carbon layer removal and slag discharge groove milling for the steel workpiece,
after the normalizing treatment, the metallographic structure of the steel workpiece processed by the heat treatment process for the steel workpiece is ferrite, fine lamellar pearlite and a small amount of upper bainite, the hardness is HRC18-21, the grain size grade is 8, the carbon concentration distribution gradient of the surface layer of the carburized steel workpiece is slow, the service life of a final finished product is prolonged by more than 25% compared with the original service life, the phenomenon that a carburized layer peels off does not occur in the use process, and the energy consumption is reduced to 65% compared with the conventional heat treatment process for the steel for the drilling tool.
Example 2
The heat treatment process of the steel workpiece comprises the following steps:
blanking is carried out according to the steel workpiece to be processed, and then forging treatment is carried out on the steel workpiece to be processed;
s1, normalizing:
s11 normalizing: putting a steel workpiece to be processed into an electric furnace, heating the electric furnace to 880 ℃ at a heating rate of 126 ℃/h, and preserving heat for 8 hours;
s12 air cooling: taking the steel workpiece after the normalizing heat treatment out of the furnace, and air-cooling until the surface temperature of the steel workpiece is reduced to 650 +/-5 ℃;
s13 heat preservation treatment: feeding the steel workpiece into an electric furnace, closing a furnace door, continuously dissipating the temperature of a core part of the steel workpiece, preserving the temperature of the steel workpiece by utilizing the self waste heat, and raising the temperature in the furnace;
repeating the step S12 when the temperature in the furnace is higher than 700 ℃;
when the final temperature in the furnace is 675 ℃, performing S14;
s14 furnace cooling: naturally cooling the steel workpiece in the furnace to below 540 +/-5 ℃, taking out the steel workpiece from the furnace, and air-cooling to room temperature;
carrying out machining treatment in rough turning, finish turning, drilling, spline milling and burr removing on the steel workpiece subjected to the normalizing treatment of S1 in sequence; then putting the workpiece on a special material rack, putting the workpiece in a cleaning furnace, cleaning the workpiece for 5-6 minutes by using cleaning fluid at 85-90 ℃, and cleaning oil stains and dust on the surface of the workpiece; transferring the cleaned workpiece into a tempering furnace, keeping the temperature at 410 +/-10 ℃ for 30 minutes, drying and preheating, and performing S2 carburizing treatment;
s2, carburizing:
s21 forced osmosis treatment: transferring the workpiece processed by the S1 into a carburizing furnace, heating to 920 +/-5 ℃ and carrying out strong permeation treatment for 4.8 h;
s22 diffusion processing: after the strong cementation treatment is finished, keeping the temperature of the carburizing furnace unchanged, and starting diffusion treatment for 6.5 hours after the carbon potential of the workpiece is reduced to the preset diffusion carbon potential;
s23 temperature equalization treatment: cooling a heating chamber of the carburizing furnace to 850 +/-10 ℃, preserving heat for 75min, transferring the workpiece to a front chamber of the carburizing furnace, slowly cooling for 2.2h, discharging and air cooling;
s24 high-temperature tempering: sending the workpiece which is air-cooled to 50-70 ℃ into a tempering furnace, tempering at the high temperature of 680 +/-10 ℃ for 6 hours, then cooling to 580 ℃ along with the furnace, discharging and putting into a slow cooling tank for slow cooling;
s3, quenching: heating the steel workpiece to 830 +/-10 ℃, preserving heat for 25-35 minutes, then quickly taking out, putting into a low-temperature nitrate furnace, keeping for 25-40 minutes, and then taking out;
s4, low-temperature tempering: heating the steel workpiece to 200 +/-10 ℃, keeping the temperature for 4-5 hours, taking out and air-cooling.
In S12, the surface temperature of the steel workpiece is monitored by an infrared thermometer.
The carbon potential of the S21 strongly cementation treatment was 1.0, and the carbon potential of the S22 diffusion treatment was 0.65.
The carburizing agent adopted in the S21 strong carburizing treatment and the S22 diffusion treatment is propane, methanol is adopted as a diluent, the carbon potential level is controlled by adjusting the flow rate of propane and methanol introduced into the carburizing furnace, the carbon potential level is detected by an infrared ray or an oxygen probe, and the temperature is controlled by a thermocouple.
After S2 and before S3, the method also comprises the treatment procedures of carbon layer removal and slag discharge groove milling for the steel workpiece,
after the normalizing treatment, the metallographic structure of the steel workpiece processed by the heat treatment process of the steel workpiece is ferrite, fine lamellar pearlite and a small amount of upper bainite, the hardness of the steel workpiece is HRC19, the grain size grade is 8, the carbon concentration distribution gradient of the surface layer of the carburized steel workpiece is slow, the service life of a final finished product is prolonged by more than 20% compared with the original service life, the phenomenon that a carburized layer peels off does not occur in the use process, and the energy consumption of the steel workpiece is reduced to 62% compared with the conventional heat treatment process of steel for a drilling tool.
Example 3
Compared with the examples, the heat treatment process of the steel workpiece of the embodiment has the following differences:
s12 air cooling: taking the steel workpiece after the normalizing heat treatment out of the furnace, and air-cooling until the surface temperature of the steel workpiece is reduced to 600 +/-5 ℃;
s21 forced osmosis treatment: transferring the workpiece processed by the S1 into a carburizing furnace, heating to 920 +/-5 ℃, carrying out strong permeation treatment for 4.5 hours, wherein the carbon potential of the strong permeation treatment is 1.03;
s22 diffusion processing: after the strong cementation treatment is finished, the temperature of the carburizing furnace is kept unchanged, and after the carbon potential of the workpiece is reduced to 0.63 of the preset diffusion carbon potential, the diffusion treatment is started for 7 hours.
After the steel workpiece treated by the heat treatment process of the steel workpiece in the embodiment is normalized, the metallographic structure of the steel workpiece is fine lamellar pearlite, a small amount of upper bainite and a small amount of pearlite, the hardness of the steel workpiece is HRC20, the grain size grade is 8, the carbon concentration distribution gradient of the surface layer of the carburized steel workpiece is slow, the service life of a final finished product is long, compared with the conventional heat treatment process of steel for a drilling tool, the energy consumption of the steel workpiece is reduced to 68% of the original energy consumption, the service life of the steel workpiece is prolonged by more than 28% of the original energy consumption, and the phenomenon that a carburized layer peels off does not occur in the.
The applicant examined the surface carbon content and the depth of the carbon layer of the carburized workpieces of examples 1 to 3, and the results are shown in table 1.
TABLE 1 relationship of surface carbon content to depth profile of carbon layer for workpieces treated in examples 1-3
According to the heat treatment process of the steel workpiece, the air cooling temperature of normalizing treatment can be adjusted according to the size and the thickness of the workpiece, and the temperature in the furnace after the workpiece is returned to the furnace can reach 680-700 ℃ according to the temperature difference between the core temperature and the surface temperature of the workpiece, so that the subsequent heat preservation treatment temperature requirements are met, for example: s12 air cooling: taking the steel workpiece after the normalizing heat treatment out of the furnace, and air-cooling until the surface temperature of the steel workpiece is reduced to 615 +/-5 ℃, 630 +/-5 ℃, 640 +/-5 ℃ or 645 +/-5 ℃; secondly, the carbon potential of the strong infiltration treatment and the diffusion treatment can be adjusted according to the carbon concentration and the carbon concentration distribution gradient of the workpiece, such as: the carbon concentration requirement is high, namely S21 strong penetration treatment can be adjusted: transferring the workpiece processed by the S1 into a carburizing furnace, heating to 920 +/-5 ℃, and carrying out strong permeation treatment for 4.5 hours, wherein the carbon potential of the strong permeation treatment is 1.2; if the carbon concentration distribution gradient is required to be gentle, the S22 diffusion process: and (3) diffusion treatment: after the strong cementation treatment is finished, keeping the temperature of the carburizing furnace unchanged, reducing the carbon potential of the workpiece to 0.7 of the preset diffusion carbon potential, and starting diffusion treatment for 6 hours; the above technical features can be understood and implemented by those skilled in the art through the text description, and therefore, the accompanying drawings are not needed to be described.
Claims (10)
1. A heat treatment process for a steel workpiece, characterized by comprising the steps of:
s1, normalizing:
s11 normalizing: putting a steel workpiece to be processed into an electric furnace, heating to 880 +/-10 ℃, and preserving heat for 6-9 hours;
s12 air cooling: taking the steel workpiece after the normalizing heat treatment out of the furnace, and air-cooling until the surface temperature of the steel workpiece is reduced to 600-650 ℃;
s13 heat preservation treatment: feeding the steel workpiece into an electric furnace, closing a furnace door, continuously dissipating the temperature of a core part of the steel workpiece, preserving the temperature of the steel workpiece by utilizing the self waste heat, and raising the temperature in the furnace;
repeating the step S12 when the temperature in the furnace is higher than 700 ℃;
when the final temperature in the furnace is 675-690 ℃, executing S14;
s14 furnace cooling: naturally cooling the steel workpiece in the furnace along with the furnace;
s2, carburizing:
s21 forced osmosis treatment: transferring the workpiece treated by the S1 into a carburizing furnace, heating to 900-930 ℃ and carrying out strong permeation treatment for 4.5-5.5 h;
s22 diffusion processing: after the strong cementation treatment is finished, keeping the temperature of the carburizing furnace unchanged, reducing the carbon potential of the workpiece to a preset diffusion carbon potential, and starting diffusion treatment for 5.5-7 hours;
s23 temperature equalization treatment: cooling a heating chamber of the carburizing furnace to 850 +/-10 ℃, preserving heat for 50-75 min, transferring the workpiece to a front chamber of the carburizing furnace, slowly cooling for 2-2.5 h, and then discharging the workpiece out of the furnace for air cooling;
s24 high-temperature tempering: sending the workpiece which is air-cooled to 50-70 ℃ into a tempering furnace, tempering at the high temperature of 680 +/-10 ℃ for 5-6 h, then cooling to 580 ℃ along with the furnace, taking out the workpiece from the furnace, and putting the workpiece into a slow cooling tank for slow cooling;
s3, quenching;
s4, low-temperature tempering: and heating the steel workpiece to 180-200 ℃, keeping the temperature for 4-5 hours, taking out and air-cooling.
2. The heat treatment process of a steel workpiece according to claim 1, characterized in that the specific operations of furnace cooling S14 are: and naturally cooling the steel workpiece in the furnace to below 550 ℃, taking out the steel workpiece from the furnace, and air-cooling to room temperature.
3. The heat treatment process for a steel workpiece according to claim 1 or 2, wherein in S12, the steel workpiece is air-cooled until the surface temperature of the steel workpiece is reduced to 640 to 650 ℃, and the surface temperature of the steel workpiece is monitored by an infrared thermometer.
4. The heat treatment process for a steel workpiece as set forth in claim 1 or 2, wherein the rate of temperature rise in the electric furnace heating to the normalizing temperature in S11 is 100 ℃/h or more.
5. The heat treatment process of a steel workpiece as defined in claim 1 or 2, further comprising, before S21, a pretreatment of the steel workpiece treated at S1 by: putting the workpiece on a special material rack, putting the workpiece in a cleaning furnace, cleaning the workpiece for 5-6 minutes by using cleaning fluid at 85-90 ℃, and cleaning oil stains and dust on the surface of the workpiece; and transferring the cleaned workpiece into a tempering furnace, and drying and preheating at the temperature of 410 +/-10 ℃ for 30-45 minutes.
6. The heat treatment process for a steel workpiece as claimed in claim 1 or 2, wherein the carbon potential of the S21 strengthening treatment is 0.98-1.03, and the carbon potential of the S22 diffusion treatment is 0.63-0.68.
7. The heat treatment process for steel workpieces according to claim 1, wherein the carburizing agent used in the S21 carburizing treatment and the S22 diffusing treatment is propane, methanol is used as a diluent, the carbon potential level is controlled by adjusting the flow rate of propane and methanol introduced into the carburizing furnace, and the carbon potential level is detected by an infrared or oxygen probe and the temperature is controlled by a thermocouple.
8. The heat treatment process for a steel workpiece according to claim 1, wherein the steel workpiece is a drill steel of 23CrNi3 MoA; before S1, forging the steel workpiece to be processed; after the step of S1, machining treatment of one or more of rough turning, finish turning, drilling, spline milling and burr removing is needed; after S2 and before S3, the method further includes a treatment process of decarburizing and milling a slag discharge groove on the steel workpiece.
9. The heat treatment process of a steel workpiece according to claim 1, characterized in that the specific operations of the S3 quenching are: heating the steel workpiece to 830 +/-10 ℃, preserving the heat for 25-35 minutes, then quickly taking out, putting into a low-temperature nitrate furnace, keeping the temperature for 25-40 minutes, and then taking out.
10. The heat treatment process of a steel workpiece according to claim 1, characterized in that the specific operations of S4 low-temperature tempering are: heating the steel workpiece to 200 +/-10 ℃, keeping the temperature for 4-5 hours, taking out and air-cooling.
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| CN117625917A (en) * | 2023-12-14 | 2024-03-01 | 扬州市海洋环保设备有限公司 | Wind power shell heat treatment device and process thereof |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102877073A (en) * | 2012-10-17 | 2013-01-16 | 常熟天地煤机装备有限公司 | Technology for processing CrNiMo series steel material |
| CN103305668A (en) * | 2013-06-18 | 2013-09-18 | 宜昌市五环钻机具有限责任公司 | Thermal treatment method of 23CrNi3Mo and application of 23CrNi3Mo in drilling tool |
| CN103882196A (en) * | 2013-12-12 | 2014-06-25 | 柳州金特机械有限公司 | Heat treatment technique for normalizing and tempering ZG35Mn steel |
| CN104070328A (en) * | 2014-06-26 | 2014-10-01 | 无锡市崇安区科技创业服务中心 | Mining roller bit steel-tooth cone manufacturing process |
| WO2015197007A1 (en) * | 2014-06-26 | 2015-12-30 | 南车戚墅堰机车车辆工艺研究所有限公司 | Carburized alloy steel, method for preparing same, and use thereof |
| CN106521402A (en) * | 2016-11-29 | 2017-03-22 | 金川集团股份有限公司 | Whole heat treatment method for 23CrNi3MoA hollow steel rock drill rod |
| CN106756753A (en) * | 2016-12-12 | 2017-05-31 | 中车戚墅堰机车车辆工艺研究所有限公司 | The carburization quenching method of low-speed heavy-loaded gear |
| CN107299202A (en) * | 2017-05-16 | 2017-10-27 | 沈阳透平机械股份有限公司 | The conditioning treatment process choice method of carburizing and quenching gear anti-distortion |
| CN108118283A (en) * | 2017-12-25 | 2018-06-05 | 南京工程学院 | A kind of surface peening heat treatment method for improving hardness gradient |
| CN111500834A (en) * | 2020-05-27 | 2020-08-07 | 江苏联峰实业有限公司 | Heat treatment process of gear steel for automobile gearbox |
-
2020
- 2020-10-23 CN CN202011142851.1A patent/CN112359178A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102877073A (en) * | 2012-10-17 | 2013-01-16 | 常熟天地煤机装备有限公司 | Technology for processing CrNiMo series steel material |
| CN103305668A (en) * | 2013-06-18 | 2013-09-18 | 宜昌市五环钻机具有限责任公司 | Thermal treatment method of 23CrNi3Mo and application of 23CrNi3Mo in drilling tool |
| CN103882196A (en) * | 2013-12-12 | 2014-06-25 | 柳州金特机械有限公司 | Heat treatment technique for normalizing and tempering ZG35Mn steel |
| CN104070328A (en) * | 2014-06-26 | 2014-10-01 | 无锡市崇安区科技创业服务中心 | Mining roller bit steel-tooth cone manufacturing process |
| WO2015197007A1 (en) * | 2014-06-26 | 2015-12-30 | 南车戚墅堰机车车辆工艺研究所有限公司 | Carburized alloy steel, method for preparing same, and use thereof |
| CN106521402A (en) * | 2016-11-29 | 2017-03-22 | 金川集团股份有限公司 | Whole heat treatment method for 23CrNi3MoA hollow steel rock drill rod |
| CN106756753A (en) * | 2016-12-12 | 2017-05-31 | 中车戚墅堰机车车辆工艺研究所有限公司 | The carburization quenching method of low-speed heavy-loaded gear |
| CN107299202A (en) * | 2017-05-16 | 2017-10-27 | 沈阳透平机械股份有限公司 | The conditioning treatment process choice method of carburizing and quenching gear anti-distortion |
| CN108118283A (en) * | 2017-12-25 | 2018-06-05 | 南京工程学院 | A kind of surface peening heat treatment method for improving hardness gradient |
| CN111500834A (en) * | 2020-05-27 | 2020-08-07 | 江苏联峰实业有限公司 | Heat treatment process of gear steel for automobile gearbox |
Non-Patent Citations (2)
| Title |
|---|
| 李美宁: ""牙轮钻头用钢及热处理"", 《第八届（2011）中国钢铁年会论文集》 * |
| 金荣植: ""常用Cr-Ni-Mo系钢齿轮的热处理工艺"", 《金属加工热加工》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117625917A (en) * | 2023-12-14 | 2024-03-01 | 扬州市海洋环保设备有限公司 | Wind power shell heat treatment device and process thereof |
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