CN114525397A - Bearing heat treatment zero decarburization and zero recarburization control method - Google Patents
Bearing heat treatment zero decarburization and zero recarburization control method Download PDFInfo
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- CN114525397A CN114525397A CN202210158401.4A CN202210158401A CN114525397A CN 114525397 A CN114525397 A CN 114525397A CN 202210158401 A CN202210158401 A CN 202210158401A CN 114525397 A CN114525397 A CN 114525397A
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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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/40—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rings; for bearing races
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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
- C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/10—Reduction of greenhouse gas [GHG] emissions
- Y02P10/143—Reduction of greenhouse gas [GHG] emissions of methane [CH4]
Abstract
The invention relates to a control method for zero decarburization and zero recarburization in bearing heat treatment, which comprises the steps of heating in a mesh belt furnace, increasing the introduction amount of nitrogen, introducing methanol and propane, raising the carbon potential in the mesh belt furnace to a process range, stopping introducing propane when the carbon potential has a strong rising trend, continuing introducing methanol, and starting feeding; in the feeding process, the introduction amount of the methanol is adjusted according to the sufficient degree of the refractory cotton of the mesh belt furnace, and the introduction amount of the methanol is finely adjusted according to a carbon control instrument, so that the carbon potential in the mesh belt furnace is stably in a process range; in the feeding process, if the carbon potential is too low, the feeding is suspended, the furnace door of the mesh belt furnace is tightly closed, and the introduction amount of methanol is increased; if the carbon potential is too high, the amount of methanol introduced is reduced. According to the invention, the propane is stopped from being introduced during normal feeding, so that the steel piece is prevented from being carburized, the methanol is continuously introduced, the steel piece is prevented from being decarburized, the introduction amount of the methanol is related to the refractory wool of the mesh belt furnace, the insufficient or excessive introduction amount of the methanol is avoided, and the production cost is favorably reduced.
Description
Technical Field
The invention relates to the technical field of heat treatment, in particular to a bearing heat treatment zero decarburization and zero recarburization control method.
Background
Decarburization means a phenomenon in which the carbon content of steel is reduced, and the strength of the steel after decarburization is reduced and softened. The carburization is a phenomenon that carbon elements are precipitated on the surface of a steel piece at high temperature, and the brittleness of the steel material with the carburization phenomenon is increased. It is seen that it is desirable to avoid excessive decarburization or excessive carburization in the heat treatment of steel parts. Conventional steel parts allow for a depth of decarburized or carburized layer, but for bearing steels, the depth requirements for the decarburized and decarburized layers are more stringent and zero decarburizing and zero carburization cannot be achieved with current heat treatment methods.
At present, the heat treatment step of the bearing steel is generally carried out by adopting a mesh belt furnace, protective gas is filled into the mesh belt furnace all the time in the whole processing process, so that the bearing steel is always in the protective gas environment, the phenomenon of excessive decarburization of a steel piece is prevented, the introduction amount of the protective gas is controlled, and the phenomenon of excessive recarburization of the steel piece is prevented. However, because the mesh belt furnace is an open structure, in order to control the carbon potential, the general method is to control the introducing amount of the protective gas of the mesh belt furnace to be far greater than the consumption amount, part of the protective gas introduced into the mesh belt furnace is burnt and lost in the furnace, and part of the protective gas is discharged out of the mesh belt furnace, and the aim is to maintain the higher protective gas concentration in the mesh belt furnace all the time. Specifically, the process of introducing the protective gas into the mesh belt furnace actually is to introduce the protective gas into the mesh belt furnace, part of the protective gas is burnt and lost in the furnace, part of the protective gas can be discharged from an inlet of the mesh belt furnace, namely the protective gas in the mesh belt furnace is always in a dynamic change state, when the introduction amount of the protective gas is far more than the consumption amount (namely the burning loss amount and the discharge amount), the protective gas in the mesh belt furnace can be continuously accumulated after a period of time, and the carbon potential in the mesh belt furnace is increased. Theoretically, after the carbon potential in the mesh belt furnace meets the requirement, the stable carbon potential can be maintained as long as the introduction amount of the protective gas is reduced, and the protective gas in the mesh belt furnace is in a dynamic balance state.
Obviously, the existing method has obvious defects, because the introduction amount of the protective gas is far more than the consumption amount, after a period of time, the inside of the mesh belt furnace is filled with the protective gas, the redundant protective gas cannot be discharged from the inlet of the mesh belt furnace in time, and the carbon potential in the furnace is difficult to control; secondly, because the relation between the protective gas introduction amount and the consumption amount is difficult to determine, the carbon potential in the mesh belt furnace is difficult to stabilize, the change of the carbon potential needs to be paid attention to and adjusted in time, more manpower is consumed, and the phenomenon of decarburization or recarburization of a steel part is easily caused due to the frequent change of the carbon potential. Therefore, it is necessary to provide a new heat treatment control method to solve the above problems.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a control method for zero decarburization and zero recarburization in heat treatment of a bearing.
The technical purpose of the invention is realized by the following technical scheme:
a bearing heat treatment zero decarburization and zero recarburization control method comprises the following specific steps:
heating in a mesh belt furnace, increasing the introduction amount of nitrogen, introducing methanol and propane, raising the carbon potential in the mesh belt furnace to a process range, indicating that the protective atmosphere in the mesh belt furnace is saturated when the carbon potential has a strong rising trend, stopping introducing the propane, continuing introducing the methanol, and starting feeding;
adjusting the introduction amount of methanol according to the sufficiency of refractory cotton at the inlet of the mesh belt furnace in the feeding process, wherein the more sufficient the refractory cotton is, the lower the introduction amount of the methanol is, and finely adjusting the introduction amount of the methanol according to a carbon control instrument to ensure that the carbon potential in the mesh belt furnace is stably in a process range;
in the feeding process, if the carbon potential is too low, stopping feeding, tightly closing a furnace door at the inlet of the mesh belt furnace, increasing the introduction amount of methanol, reducing the introduction amount of the methanol when the carbon potential is restored to be within the process range, and normally feeding again; if the carbon potential is too high, the introduction amount of the methanol is reduced, and after the carbon potential is restored to the process range, the introduction amount of the methanol is increased, and the normal feeding is carried out again.
In one embodiment, when the process needs to be converted or feeding needs to be interrupted or the empty furnace needs to be insulated, the opening degree of a furnace door at the inlet of the mesh belt furnace is reduced, the introduction amount of methanol is reduced, the introduction amount of the methanol is finely adjusted according to a carbon control instrument, and the carbon potential is kept stable in the process range.
In one embodiment, the methanol feed is 80-90ml/min and the propane feed is 550-600ml/min prior to normal feed.
In one embodiment, the amount of methanol introduced during normal feeding is controlled to be 15-90 ml/min.
In one embodiment, in the feeding process, if the carbon potential is too low, the feeding is suspended, the furnace door of the inlet of the mesh belt furnace is closed, propane is also introduced, the propane introduction amount is less than or equal to 600ml/min, and the propane introduction is stopped when the carbon potential is recovered to be within the process range.
In one embodiment, in the feeding process, when the carbon potential is too high, if the carbon potential is still in a higher state after the introduction amount of the methanol is adjusted or the original introduction amount of the methanol is lower, the opening degree of an inlet furnace door of the mesh belt furnace is increased, the opening degree of the furnace door is kept, the introduction amount of the methanol is finely adjusted according to a carbon control instrument, so that the carbon potential is stably in a process range, and then the feeding is performed normally.
In one embodiment, the nitrogen flow is increased to 500-600 ml/min.
In one embodiment, during the feeding process, the introduction amount of nitrogen is adjusted according to the sufficiency of refractory cotton at the inlet of the mesh belt furnace;
when the refractory cotton is sufficient, the introduction amount of the nitrogen is 500-550 ml/min; when the refractory cotton is insufficient, the nitrogen gas is introduced at 550-600 ml/min.
In one embodiment, the process range refers to a carbon potential in the range of 0.45 to 0.95.
In one embodiment, the process range refers to a carbon potential in the range of 0.8 to 0.95.
In conclusion, the invention has the following beneficial effects:
according to the invention, methanol and propane are used as protective gas before feeding, the introduction amount of nitrogen is increased, the propane introduction is stopped when the carbon potential in the mesh belt furnace reaches the process range, the methanol is continuously introduced, the methanol and the nitrogen are used as the protective gas in the feeding process, and the introduction amount of the methanol and the nitrogen is related to the sufficient degree of refractory cotton in the mesh belt furnace, so that the difficulty of adjusting the introduction amount of the protective gas is reduced, the carbon potential in the mesh belt furnace is favorably maintained in the process range all the time, zero recarburization and zero decarburization in the bearing steel heat treatment step are realized, and the production cost is favorably reduced.
Detailed Description
The present invention will be described in detail with reference to examples.
At present, the heat treatment step of bearing steel is generally carried out by adopting a mesh belt furnace, protective gas is always filled into the mesh belt furnace in the whole processing process, so that the bearing steel is always in the protective gas environment, in order to prevent the decarburization of a steel piece, gases such as methanol, propane and the like are generally adopted as the protective gas, and the methanol and the propane are continuously introduced in the whole processing process. However, when methanol and propane are excessive, the steel member is rather carburetted, and therefore the carbon potential in the mesh belt furnace needs to be kept within a stable range in general.
The process of letting in protective gas to the guipure stove is actually, let in protective gas to the guipure stove, and partial protective gas burns in the stove and consumes, and partial protective gas is discharged from guipure stove import department, also is that protective gas in the guipure stove is in dynamic change's state all the time, when protective gas's the volume of letting in far than the consumption (be burning loss volume + discharge amount) is many, the protective gas that is not burnt and consumes can not all in time discharge the guipure stove, after a period of time, protective gas can constantly accumulate in the guipure stove, leads to the interior carbon potential of guipure stove to increase. Theoretically, after the carbon potential in the mesh belt furnace meets the requirement, the stable carbon potential can be maintained as long as the introduction amount of the protective gas is reduced, and the protective gas in the mesh belt furnace is in a dynamic balance state.
The invention relates to the fact that the consumption of protective gas is related to refractory cotton at the inlet of a mesh belt furnace, and therefore provides a control method for zero decarburization and zero recarburization in bearing heat treatment, which comprises the following specific steps:
under a general state, nitrogen in the mesh belt furnace is in a normally open state, the introduction amount of the nitrogen is about 100-plus 200ml/min, the temperature in the mesh belt furnace is increased, the introduction amount of the nitrogen is increased (for example, when the temperature in the mesh belt furnace is increased to about 750 ℃, the introduction amount of the nitrogen is increased at one time), methanol and propane are introduced, the methanol and the propane are both used as protective gases, the carbon potential in the mesh belt furnace is increased to a process range, when the carbon potential has a strong rising trend, the protective atmosphere in the mesh belt furnace is saturated, the propane introduction is stopped, the methanol introduction is continued, and the feeding is started.
The prior conventional method is to simultaneously introduce methanol and propane all the time, and because two gases are simultaneously introduced, when the protective atmosphere in a mesh belt furnace is saturated, the two gases of methanol and propane are simultaneously adjusted to achieve the dynamic balance of the protective gas in the furnace. In the invention, methanol and propane are only introduced at the same time in the temperature rise stage of the mesh belt furnace, so that the rising rate of the carbon potential in the furnace is improved, when the carbon potential in the mesh belt furnace rises to the process range, the propane introduction is stopped, the carbon potential is prevented from being overhigh, but the methanol is continuously introduced, so that the carbon potential in the furnace is maintained in a stable range, and the adjustment of the methanol is relatively simple because only one gas of the methanol is introduced. In the present invention, the process range means that the carbon potential has a value in the range of 0.45 to 0.95, and preferably, the carbon potential has a value in the range of 0.8 to 0.95.
Specifically, the amount of methanol introduced was 80 to 90ml/min and the amount of propane introduced was 500-600ml/min before the normal feed.
The introduction amount of methanol is adjusted according to the sufficient degree of refractory cotton at the inlet of the mesh belt furnace in the feeding process, the more sufficient the refractory cotton is, the lower the introduction amount of the methanol is, and the introduction amount of the methanol is finely adjusted according to a carbon control instrument, so that the carbon potential in the mesh belt furnace is stably in the process range. Specifically, during the normal feeding, the amount of methanol fed was controlled to 15-90ml/min, and the amount of nitrogen fed was 500-600 ml/min.
The invention directly relates the introduction amount of the protective gas (namely methanol) to the sufficiency of the refractory cotton at the inlet of the mesh belt furnace. When the refractory wool is sufficient, the blocking effect on the furnace door is better, methanol gas in the mesh belt furnace is more difficult to discharge, the surface of a steel part is easily carburized, the introduction amount of the methanol needs to be reduced, on the contrary, when the refractory wool is insufficient, the methanol gas in the mesh belt furnace is easy to discharge, and in order to maintain the carbon potential in the mesh belt furnace, the introduction amount of the methanol needs to be increased.
It should be noted that, in the present invention, only methanol gas is introduced during the feeding process, and the difficulty of adjusting the introduction amount of the shielding gas is also considered, and if methanol and propane are always introduced simultaneously during the feeding process, it is difficult to accurately control the ratio of methanol and propane when adjusting the introduction amount of the shielding gas.
In addition, in the feeding process, the introduction amount of nitrogen is adjusted according to the sufficiency of the refractory cotton at the inlet of the mesh belt furnace; when the refractory cotton is sufficient, the introduction amount of the nitrogen is 500-550ml/min, such as 500 ml/min; when the refractory cotton is insufficient, the nitrogen gas is introduced in an amount of 550-600ml/min, such as 600 ml/min.
Specifically, when the refractory wool is sufficient, nitrogen is more difficult to discharge, and in order to ensure that the content of methanol in the mesh belt furnace is maintained at a normal level, the introduction amount of nitrogen needs to be reduced, the reduction of the consumption amount of methanol combusted in the furnace is prevented, and the recarburization of steel parts is prevented, because the nitrogen plays a role in maintaining a low-oxygen environment in the furnace, if the refractory wool is sufficient, the introduction amount of nitrogen is still maintained in a high state, the consumption amount of methanol combusted in the furnace is relatively reduced, the amount of methanol accumulated in the furnace is relatively increased, and the recarburization of steel parts is caused, so the introduction amount of nitrogen also needs to be reduced when the refractory wool is sufficient;
when the fire-resistant cotton is not enough, the volume of letting in of nitrogen gas also needs the increase, this is because when the fire-resistant cotton is not enough, if the volume of letting in of nitrogen gas still maintains lower state this moment, the air can get into the stove and react with methyl alcohol, the volume that methyl alcohol was consumed increases, the stove methyl alcohol is all consumed when serious, can not play the effect of protective gas, the phenomenon of decarbonization can appear in the steel spare, consequently, the volume of letting in of increase nitrogen gas prevents that methyl alcohol from burning the consumption completely in the stove, thereby prevent the steel spare decarbonization.
It should be noted that, when the amount of methanol or nitrogen introduced is adjusted according to the sufficiency of the refractory cotton, the adjustment degree of the amount of methanol or nitrogen introduced needs to be judged according to the real-time monitoring of the carbon control instrument, so that the carbon potential in the furnace is always within the process range.
In the feeding process, if the carbon potential is too low, stopping feeding, tightly closing a furnace door at the inlet of the mesh belt furnace, increasing the introduction amount of methanol, reducing the introduction amount of the methanol when the carbon potential is restored to be within the process range, and normally feeding again; if the carbon potential is too high, the introduction amount of the methanol is reduced, and after the carbon potential is restored to the process range, the introduction amount of the methanol is increased, and the normal feeding is carried out again.
And aiming at the condition of excessively low carbon potential, not only increasing the introduction amount of formaldehyde, but also introducing propane again, wherein the introduction amount of propane is less than or equal to 600ml/min, and stopping introducing propane when the carbon potential is recovered to be within the process range.
In addition, aiming at the condition of overhigh carbon potential, if the carbon potential is still in a higher state after the introduction amount of the methanol is adjusted or the original introduction amount of the methanol is lower, the opening degree of an inlet furnace door of the mesh belt furnace is increased, the opening degree of the furnace door is kept, the introduction amount of the methanol is finely adjusted according to a carbon control instrument, so that the carbon potential is stably in a process range, and then the materials are normally fed. It should be noted that the opening of the furnace door cannot be too large, and normal feeding cannot be affected.
In the invention, when the process needs to be converted, the feeding needs to be interrupted or the empty furnace needs to be insulated, the opening degree of the furnace door at the inlet of the mesh belt furnace is reduced, the introduction amount of the methanol is finely adjusted according to a carbon control instrument, and the carbon potential is kept stable in the process range.
The specific control method of the present invention is explained below by specific examples.
Example 1
After the temperature of a mesh belt furnace is raised, increasing the introduction amount of nitrogen, and starting to introduce methanol and propane as protective gas, wherein the introduction amount of methanol is 90ml/min, the introduction amount of propane is 600ml/min, after the carbon potential rises to a process range (taking bearing steel 0.8-0.95 as an example), when the carbon potential has a strong rising trend, indicating that the atmosphere in the furnace is saturated, stopping introducing propane, continuing to introduce methanol, and starting to feed, and under no special condition, generally not introducing propane in the feeding process;
during normal feeding, controlling the introduction amount of methanol at 15-90ml/min, and keeping the carbon potential stable in a process range all the time by controlling the methanol introduction amount to be lower as the refractory cotton is more sufficient and the methanol introduction amount is lower according to whether the refractory cotton is sufficient at the current stage or not and performing fine adjustment according to the display of a carbon control instrument;
when the process needs to be converted or the feeding needs to be interrupted or the empty furnace needs to be insulated, the opening degree of a furnace door at the inlet of the mesh belt furnace is reduced, the introduction amount of the methanol is finely adjusted according to a carbon control instrument, and the carbon potential is kept stable in the process range;
the nitrogen introduction amount is 500-600ml/min, when the temperature of the mesh belt furnace is raised to 750-800 ℃, the nitrogen introduction amount is adjusted in place at one time, in order to match the change of the methanol introduction amount, when the refractory cotton is sufficient, the nitrogen introduction amount is about 500ml/min, when the refractory cotton is insufficient, the nitrogen introduction amount is about 600ml/min, and if no special requirements exist in the feeding process, the nitrogen introduction amount is not adjusted at will;
if the carbon potential is too low due to abnormality in the feeding process, feeding can be suspended, the furnace door is tightly closed, the introduction amount of the methanol is increased, and then the propane can be introduced again, wherein the introduction amount of the methanol is not more than 90ml/min, the introduction amount of the propane is not more than 600ml/min, the feeding is continued after the protective atmosphere is recovered, otherwise, when the carbon potential is too high, the introduction amount of the methanol is reduced, if the effect is not obvious or the introduction amount of the methanol is low originally, the furnace door can be slightly pulled up to reduce the carbon potential, and then the normal feeding is carried out.
Example 2
After the temperature of a mesh belt furnace is raised, increasing the introduction amount of nitrogen, and starting to introduce methanol and propane as protective gas, wherein the introduction amount of methanol is 30ml/min x 3 (meaning that methanol is introduced into three pipelines simultaneously), the introduction amount of propane is 600ml/min, after the carbon potential rises to a process range (taking bearing steel 0.8-0.95 as an example), when the carbon potential has a strong rising trend, indicating that the atmosphere in the furnace is saturated, stopping introducing propane, continuing to introduce methanol, and starting to feed, and under no special condition, generally not introducing propane in the feeding process;
during normal feeding, controlling the introduction amount of methanol to be 5-30ml/min x 3 (meaning that methanol is introduced into three pipelines simultaneously), and referring to whether refractory cotton is sufficient at the current stage, the more sufficient the refractory cotton is, the lower the introduction amount of methanol is, and fine adjustment is performed according to the display of a carbon control instrument, so that the carbon potential is always kept stable in a process range;
when the process needs to be converted or the feeding needs to be interrupted or the empty furnace needs to be insulated, the opening degree of a furnace door at the inlet of the mesh belt furnace is reduced, the introduction amount of the methanol is finely adjusted according to a carbon control instrument, and the carbon potential is kept stable in the process range;
the nitrogen introduction amount is 500-600ml/min, when the temperature of the mesh belt furnace is raised to 750-800 ℃, the nitrogen introduction amount is adjusted in place at one time, in order to match the change of the methanol introduction amount, when the refractory cotton is sufficient, the nitrogen introduction amount is about 500ml/min, when the refractory cotton is insufficient, the nitrogen introduction amount is about 600ml/min, and if no special requirements exist in the feeding process, the nitrogen introduction amount is not adjusted at will;
if the carbon potential is too low due to abnormality in the feeding process, feeding can be suspended, the furnace door is tightly closed, the introduction amount of the methanol is increased, and then the propane can be introduced again, wherein the introduction amount of the methanol is not more than 90ml/min, the introduction amount of the propane is not more than 600ml/min, the feeding is continued after the protective atmosphere is recovered, otherwise, when the carbon potential is too high, the introduction amount of the methanol is reduced, if the effect is not obvious or the introduction amount of the methanol is low originally, the furnace door can be slightly pulled up to reduce the carbon potential, and then the normal feeding is carried out.
Example 3
After the temperature of a mesh belt furnace is raised, increasing the introduction amount of nitrogen, and starting to introduce methanol and propane as protective gas, wherein the introduction amount of methanol is 85ml/min, the introduction amount of propane is 600ml/min, after the carbon potential rises to a process range (taking bearing steel 0.8-0.95 as an example), when the carbon potential has a strong rising trend, indicating that the atmosphere in the furnace is saturated, stopping introducing propane, continuing to introduce methanol, and starting to feed, and under no special condition, generally not introducing propane in the feeding process;
during normal feeding, controlling the introduction amount of methanol to be 20-80ml/min, and keeping the carbon potential stable in a process range all the time by controlling the methanol introduction amount to be lower as the refractory cotton is more sufficient and the methanol introduction amount is lower according to whether the refractory cotton is sufficient or not at the current stage and according to the display of a carbon control instrument;
when the process needs to be converted or the feeding needs to be interrupted or the empty furnace needs to be insulated, the opening degree of a furnace door at the inlet of the mesh belt furnace is reduced, the introduction amount of the methanol is finely adjusted according to a carbon control instrument, and the carbon potential is kept stable in the process range;
the nitrogen introduction amount is 500-600ml/min, when the temperature of the mesh belt furnace is raised to 750-800 ℃, the nitrogen introduction amount is adjusted in place at one time, in order to match the change of the methanol introduction amount, when the refractory cotton is sufficient, the nitrogen introduction amount is about 500ml/min, when the refractory cotton is insufficient, the nitrogen introduction amount is about 600ml/min, and if no special requirements exist in the feeding process, the nitrogen introduction amount is not adjusted at will;
if the carbon potential is too low due to abnormality in the feeding process, feeding can be suspended, the furnace door is tightly closed, the introduction amount of the methanol is increased, and then the propane can be introduced again, wherein the introduction amount of the methanol is not more than 85ml/min, the introduction amount of the propane is not more than 600ml/min, the feeding is continued after the protective atmosphere is recovered, otherwise, when the carbon potential is too high, the introduction amount of the methanol is reduced, if the effect is not obvious or the introduction amount of the methanol is low originally, the furnace door can be slightly pulled up to reduce the carbon potential, and then the normal feeding is carried out.
It should be noted that, because the refractory cotton at the inlet of the mesh belt furnace is easily damaged, if the protective gas in the mesh belt furnace is not sufficient due to the failure to replace the damaged refractory cotton in time, the flow of the protective gas is properly increased, and the carbon potential temperature in the mesh belt furnace is ensured to be within the process range.
The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.
Claims (10)
1. A bearing heat treatment zero decarburization and zero recarburization control method is characterized in that a mesh belt furnace is heated, the introduction amount of nitrogen is increased, methanol and propane are introduced, the carbon potential in the mesh belt furnace is increased to a process range, when the carbon potential has a strong rising trend, the protective atmosphere in the mesh belt furnace is saturated, the introduction of propane is stopped, the methanol is continuously introduced, and feeding is started;
adjusting the introduction amount of methanol according to the sufficiency of refractory cotton at the inlet of the mesh belt furnace in the feeding process, wherein the more sufficient the refractory cotton is, the lower the introduction amount of the methanol is, and finely adjusting the introduction amount of the methanol according to a carbon control instrument to ensure that the carbon potential in the mesh belt furnace is stably in a process range;
in the feeding process, if the carbon potential is too low, stopping feeding, tightly closing a furnace door at the inlet of the mesh belt furnace, increasing the introduction amount of methanol, reducing the introduction amount of the methanol when the carbon potential is restored to be within the process range, and normally feeding again; if the carbon potential is too high, the introduction amount of the methanol is reduced, and after the carbon potential is restored to the process range, the introduction amount of the methanol is increased, and the normal feeding is carried out again.
2. The method for controlling zero decarburization and zero recarburization in heat treatment of bearings according to claim 1, wherein when the process needs to be switched or the feeding needs to be interrupted or the empty furnace needs to be kept warm, the opening degree of the furnace door at the inlet of the mesh belt furnace is reduced, the introduction amount of methanol is finely adjusted according to a carbon controller, and the carbon potential is kept stable within the process range.
3. The method as claimed in claim 1, wherein the methanol is introduced at a rate of 80-90ml/min and the propane is introduced at a rate of 550-600ml/min before the normal feeding.
4. The method for controlling zero decarburization and zero recarburization in heat treatment of a bearing as set forth in claim 1, wherein the amount of methanol introduced during normal feed is controlled to 15 to 90 ml/min.
5. The method for controlling zero decarburization and zero recarburization in heat treatment of bearings according to claim 3, wherein in the feeding process, if the carbon potential is too low, feeding is suspended, the furnace door of the inlet of the mesh belt furnace is closed, propane is also fed, the feeding amount of propane is less than or equal to 600ml/min, and the feeding of propane is stopped when the carbon potential is restored to the process range.
6. The method for controlling zero decarburization and zero recarburization in heat treatment of bearings according to claim 1, wherein in the feeding process, when the carbon potential is too high, if the carbon potential is still in a higher state after the introduction amount of methanol is adjusted or the original introduction amount of methanol is lower, the opening degree of the furnace door at the inlet of the mesh belt furnace is increased, the opening degree of the furnace door is maintained, the introduction amount of methanol is finely adjusted according to a carbon controller, so that the carbon potential is stably in the process range, and then the materials are normally fed.
7. The method as claimed in claim 1, wherein the nitrogen is introduced in an amount of 500-600 ml/min.
8. The method for controlling zero decarburization and zero recarburization in heat treatment of bearings according to claim 7, wherein the amount of nitrogen introduced is adjusted according to the sufficiency of refractory cotton at the inlet of the mesh belt furnace during feeding;
when the refractory cotton is sufficient, the introduction amount of the nitrogen is 500-550 ml/min; when the refractory cotton is insufficient, the nitrogen gas is introduced at 550-600 ml/min.
9. The method for controlling zero decarburization and zero recarburization in heat treatment of a bearing according to claim 1, wherein the process range means that the carbon potential is in the range of 0.45 to 0.95.
10. The method for controlling zero decarburization and zero recarburization in heat treatment of a bearing as set forth in claim 9, wherein the process range means that the carbon potential is in the range of 0.8 to 0.95.
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| CN109778106A (en) * | 2018-11-14 | 2019-05-21 | 苏州工业园区姑苏科技有限公司 | A kind of control system and adjusting method of the n-formyl sarcolysine alcohol protective atmosphere of meshbeltfurnace |
| CN110408830A (en) * | 2019-08-28 | 2019-11-05 | 三峡大学 | A kind of Ti (C, N) base metal-ceramic material and its Carbon balance control method |
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| US6106636A (en) * | 1997-02-18 | 2000-08-22 | Dowa Mining Co., Ltd. | Method and apparatus for controlling the atmosphere in a heat treatment furnace |
| CN102766743A (en) * | 2011-05-06 | 2012-11-07 | 贵州汇新科技发展有限公司 | Railway freight car brake round pin surface controlled atmosphere heat treatment |
| CN104342535A (en) * | 2013-07-29 | 2015-02-11 | 宝山钢铁股份有限公司 | Method and apparatus for cooling multi-atmosphere segment continuous annealing furnace |
| CN106065429A (en) * | 2016-07-21 | 2016-11-02 | 洛阳Lyc轴承有限公司 | A kind of method ensureing that bearing parts hot consequent surface color is consistent |
| CN109778106A (en) * | 2018-11-14 | 2019-05-21 | 苏州工业园区姑苏科技有限公司 | A kind of control system and adjusting method of the n-formyl sarcolysine alcohol protective atmosphere of meshbeltfurnace |
| CN110408830A (en) * | 2019-08-28 | 2019-11-05 | 三峡大学 | A kind of Ti (C, N) base metal-ceramic material and its Carbon balance control method |
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