CN113215519A - Muffle-tank-free carbon saturation control process - Google Patents
Muffle-tank-free carbon saturation control process Download PDFInfo
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- CN113215519A CN113215519A CN202110416053.1A CN202110416053A CN113215519A CN 113215519 A CN113215519 A CN 113215519A CN 202110416053 A CN202110416053 A CN 202110416053A CN 113215519 A CN113215519 A CN 113215519A
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 85
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 85
- 238000000034 method Methods 0.000 title claims abstract description 32
- 230000008569 process Effects 0.000 title claims abstract description 27
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 38
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 36
- 238000010438 heat treatment Methods 0.000 claims abstract description 30
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 claims abstract description 24
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 19
- 239000001294 propane Substances 0.000 claims abstract description 12
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229920006395 saturated elastomer Polymers 0.000 claims abstract description 8
- 239000013256 coordination polymer Substances 0.000 claims description 3
- 238000005255 carburizing Methods 0.000 abstract description 16
- 230000000694 effects Effects 0.000 abstract description 6
- 238000003825 pressing Methods 0.000 abstract description 2
- 239000006229 carbon black Substances 0.000 description 9
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 8
- 239000001301 oxygen Substances 0.000 description 8
- 229910052760 oxygen Inorganic materials 0.000 description 8
- 239000000523 sample Substances 0.000 description 8
- 239000006185 dispersion Substances 0.000 description 7
- 230000009467 reduction Effects 0.000 description 7
- 125000004432 carbon atom Chemical group C* 0.000 description 5
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 150000001721 carbon Chemical class 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 241001391944 Commicarpus scandens Species 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 230000014509 gene expression Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
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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
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
The invention relates to the technical field of heat treatment, in particular to a muffle-tank-free carbon saturation control process, which comprises the following steps: step 1: heating a hearth, and closing nitrogen, methanol and propane during heating; step 2: heating the master control temperature to a first set temperature range, upwards opening the furnace cover, wherein the opening stroke of the furnace cover is smaller than the full opening stroke, burning carbon, and closing nitrogen, methane and propane during the carbon burning; and step 3: keeping the main control temperature in a first set temperature range, continuing to heat until the zone temperature reaches a peak value and begins to drop, prolonging the first set time after the zone temperature reaches the peak value, closing the furnace cover, and pressing the safety hand wheel; and 4, step 4: introducing nitrogen to keep the second set time and ensure that the furnace pressure is in the set pressure numerical range; and 5: the main control temperature is controlled within a second set temperature range, methanol and propane are introduced, after the carbon potential is reduced to a target value, saturated carburizing is carried out for keeping a third set time, and the carbon saturation control effect is accurately achieved through extreme temperature balance.
Description
Technical Field
The invention relates to the technical field of heat treatment, in particular to a muffle-tank-free carbon saturation control process.
Background
In the existing carburizing heat treatment industry, the 3 m-diameter large-scale well-type carburizing furnace is mainly designed to have a muffle tank, and the heating wire and the hearth atmosphere are shielded by the muffle tank, but the main defect of the muffle furnace is that the replacement cost is high and the lifting operation is complex after the service life of the muffle tank is over. Based on the realistic cost characteristic, the industry produces a muffle-free design, the design of a W-shaped carburizable fast-cooling hollow heating rod (furnace body external cold air, the hollow heating rod is used for cooling a carburized workpiece in a hearth), a muffle tank is cancelled, the air guide cylinder is used for forcing the atmosphere to circulate, the design of the muffle-free tank has the greatest advantage of no great cost problem of the muffle tank, but after the design of the muffle-free tank is actually used, the defect is found to be great, namely, a furnace lining of the muffle-free furnace is directly contacted with the carburization atmosphere, after long-time carburization, a great amount of carbon atoms are particularly permeated into loose refractory bricks of the furnace lining, the carbon supersaturation on the surface of the furnace lining is caused, a great amount of carbon black is formed as a result of supersaturation, the excessive carbon black causes slow carburization and carbon reduction, the carburized workpiece is easy to exceed the standard, and meanwhile, the design of the muffle-free tank is easy to cause the serious internal oxidation problem due to carbon shortage.
The large muffle-free tank well type carburizing furnace has large dosage of carburizing and enriching gas medium, and has the following main defects after long-time carburization:
(1) the furnace lining participates in the carburization reaction, so that carbon is easily supersaturated, and when the carbon reduction potential of the hearth is reduced, supersaturated carbon atoms are continuously released by the furnace lining, and the carbon reduction potential is slow, so that the accurate control of the carbon diffusion potential is difficult.
(2) The hollow W-shaped heating rod is in contact with the carburizing atmosphere, supersaturated carbon black is enriched on the surface of the heating rod, the heating rod is reduced in plasticity and easy to break, and the hollow design capable of realizing carburizing and quick cooling can generate a huge safety problem, namely the carburizing atmosphere overflows out of a furnace shell, and the problems of gas explosion and CO standard exceeding are easily generated.
(3) The furnace mouth heat preservation cotton is in direct contact with the carburizing atmosphere, so that a large amount of supersaturated carbon black is easy to accumulate, and the accuracy of control of the diffused carbon potential is influenced.
(4) As the furnace lining continuously releases carbon atoms, the carbon potential in the hearth is high, the oxygen probe is easy to deposit carbon, the carbon potential control of the oxygen probe is ineffective, the problems of overproof carbide and overproof hardened layer are easy to generate, meanwhile, the structural parts in the hearth are corroded, and the service lives of an air guide cylinder, a heating rod, an air guide cylinder cover and the like are shortened.
The conventional muffle tank-free carburizing furnace has a simple carbon burning process, the conventional process is more than 860 ℃, the furnace cover is opened to contact and control natural combustion for hours, and the process has two obvious disadvantages: firstly, the burning time is long, and the cost is high; secondly, the effect of controlling carbon saturation cannot be accurately controlled, and for a state with extremely serious carbon supersaturation, the combustion effect may not realize carbon saturation; and for carbon supersaturated light state, the fuel is easy to burn excessively, so that carbon is lack.
Disclosure of Invention
In order to solve the problem that the existing muffle-free tank in the prior art cannot accurately control the carbon saturation effect, the invention provides a muffle-free tank carbon saturation control process for accurately controlling the carbon saturation effect.
The technical scheme adopted by the invention for solving the technical problems is as follows:
the muffle-free tank comprises a furnace shell and a furnace cover positioned above the furnace shell, a furnace lining is arranged in the furnace shell, an oxygen probe and a master control thermocouple for measuring master control temperature are arranged below the furnace cover, and a zone thermocouple for measuring zone temperature is arranged in the furnace lining; a carbon saturation control process without a muffle tank,
the method comprises the following steps:
step 1: heating a hearth, and closing nitrogen, methanol and propane during heating;
step 2: the main control temperature is increased to a first set temperature range, the furnace cover is opened upwards, the opening stroke of the furnace cover is smaller than the full opening stroke, preferably, the furnace cover is opened upwards to 1/2 of the full opening stroke, for example, the full opening stroke of the furnace cover is about 500 mm, and is only opened for 250mm, so that an oxygen probe, a main control thermocouple and a drip hole in a hearth are ensured to be in an air environment for burning carbon, and nitrogen, methane and propane are closed during the carbon burning;
and step 3: keeping the main control temperature in a first set temperature range, continuing to heat until the zone temperature reaches a peak value and begins to drop, prolonging the first set time after the zone temperature reaches the peak value, closing the furnace cover, and pressing the safety hand wheel;
and 4, step 4: introducing nitrogen to keep the second set time and ensure that the furnace pressure is in the set pressure numerical range;
and 5: and controlling the main control temperature within a second set temperature range, introducing methanol and propane, and keeping saturated carburization for a third set time after the carbon potential is reduced to a target value.
Further, the first set temperature range is 930-950 ℃.
Further, the first set time is 8-12 min.
Further, the second set time is 1 hour or more.
Further, the pressure value range is set to 200-400 Pa.
Further, the second set temperature range is 860-950 ℃.
Further, the nitrogen flow is at least 1 furnace volume.
Furthermore, the flow ratio of the nitrogen to the methanol is 1: 1-1.2: 1. Preferably, the ratio of nitrogen: methanol 1.1: 1.
Further, the third setting time is 2 h.
Further, in the step 5, the carbon potential CP is reduced to 0.75-0.85%.
Has the advantages that:
(1) accurately controlling the carbon saturation effect through the equilibrium time of the extreme temperature in the furnace;
(2) the carbon potential reduction time of the carbon saturation control process is reduced within 1 hour from 1 to 3 hours of the conventional process, so that the production and heating cost is greatly reduced;
(3) realizing an accurate furnace lining carbon reservoir concentration value through rapid saturated carburizing;
(4) the problems of poor control accuracy and easiness in internal oxidation of the carbon potential of the large-scale muffle-free carburizing furnace are solved, and the internal oxidation meets the requirements of ISO6336-5-2016ME level;
(5) the carbon concentration dispersion degree and reliability of the carburized part are improved, the dispersion degree of the conventional 1-4-grade carbide is improved to a stable state 1 grade, and the product quality and the dispersion degree are greatly improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
FIG. 1 is a schematic diagram of a carbon reduction potential and its steady state control process;
FIG. 2 is a schematic view showing the temperature change in the carbon-burning furnace;
FIG. 3 is a schematic diagram of the degree of dispersion of the surface texture of a product obtained by the muffle tank-free carbon saturation control process of the present invention;
FIG. 4 is a schematic view of the internal structure of a muffle-free tank.
The device comprises a furnace lining 1, a furnace lining 2, a heating rod 3, an air guide cylinder 41, a master control thermocouple 42, a zone thermocouple 5, an oxygen probe 6, a furnace shell 7 and a furnace cover.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
In the description of the present invention, it is to be understood that the orientation or positional relationship indicated by the orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc. are usually based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and in the case of not making a reverse description, these orientation words do not indicate and imply that the device or element being referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore, should not be considered as limiting the scope of the present invention; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.
Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of the present invention should not be construed as being limited.
The large-scale muffle tank well type carburizing furnace has less carbon deposition and does not have the problem of supersaturated carbon atoms, so the process for realizing carbon saturation in the furnace chamber is that supersaturated carbon black is naturally combusted by contacting air when the furnace is taken out at 840-880 ℃ after carburization. A large-scale shaft type muffle-free furnace is designed into a carburizing furnace, only one carburizing furnace manufacturer of Austria in the world has the patent, the structural equipment has fewer domestic numbers, the problem that the carbon supersaturation of the structural equipment is easy to occur can be accurately solved, and no related manufacturers can accurately control the carbon supersaturation problem of the large-scale muffle-free tank carburizing furnace at home.
The muffle-free tank has an internal structure shown in figure 4, and comprises a furnace shell 6 and a furnace cover 7 positioned above the furnace shell 6, wherein a furnace lining 1 is arranged in the furnace shell 6, an oxygen probe 5 and a master control thermocouple 41 for measuring master control temperature are arranged below the furnace cover 7, a zone thermocouple 42 for measuring zone temperature is arranged in the furnace lining 1, a heating rod 2, an air guide cylinder 3 and the like are also arranged in the zone thermocouple, the carbon concentration of the surface of the furnace lining 1 and the like in a hearth has three states, one state is carbon saturation, namely, excessive carbon black accumulation does not exist, and the carbon is not depleted; secondly, carbon supersaturation, namely excessive carbon black is accumulated on the surfaces of the furnace lining 1, the heating rod 2, the air duct 3 and the like, and the control of carbon reduction potential is influenced; and thirdly, carbon is undersaturated, namely the surface carbon concentration of the furnace lining 1, the heating rod 2, the air duct 3 and the like is insufficient, namely carbon is poor, and the carbon is undersaturated, namely carbon is poor, the carbon potential is built very slowly after carburization enters the furnace, the enriching atmosphere is mainly absorbed by the furnace lining 1, the air duct 3 and the like, redundant carbon atoms are not involved in temperature rise and exhaust and air combustion, the air reacts with alloy elements on the metal surface of a workpiece at high temperature, serious internal oxidation is easily caused, and meanwhile, the slow establishment of the carbon potential also means that the heating cost is increased.
The carbon saturation process of the invention comprises the following steps: at high temperature of a hearth, introducing air of the external environment, enabling carbon black in the hearth and an oxygen probe 5 to react with the air to form carbon slag and the like, burning off the carbon black to realize controllable carbon potential, immediately carrying out saturated carburization on the hearth after carbon burning, wherein a saturated concentration value is equal to a diffusion carbon potential value of a conventional carburization piece, and the saturated carburization provides a furnace lining 1 carbon base to realize quick, uniform and stable carbon potential control of a subsequent carburized workpiece. The method comprises the following specific steps:
a muffle-tank-free carbon saturation control process comprises the following steps:
step 1: heating a hearth, and closing nitrogen, methanol and propane during heating;
step 2: the main control temperature is increased to a first set temperature range, and the first set temperature range is 930-950 ℃. The furnace cover 7 is opened upwards, the opening stroke of the furnace cover 7 is smaller than the full opening stroke, the oxygen probe 5, the master control thermocouple 41, the drip injection port and the like in the hearth are ensured to be in the air environment, carbon burning is carried out, and nitrogen, methane and propane are closed during the carbon burning;
in general heating, the furnace cover 7 is required to descend to a certain position and is automatically pressed to the limiting device, at the moment, the program knows that the furnace cover 7 is closed, and at the moment, the power can be switched on. And in the step 2, the furnace cover 7 is in a partially opened state, the limiting device cannot be pressed, and the limiting device needs to be pressed manually, so that the program senses the indication that current heating can be carried out.
And step 3: the main control temperature keeps the first set temperature range to continue heating until the zone temperature reaches the peak value and begins to decrease, and as an embodiment, the zone temperature comprises three zones, namely, the heating rods 2 are arranged in the upper, middle and lower zones in the furnace body, namely, three circles are distributed in the upper, middle and lower zones, and the temperatures of the upper, middle and lower zones are measured by the zone thermocouples 42 in fig. 3, and as shown in fig. 2, the temperatures of the three zones generally reach the peak value at the same time. And after the peak value is reached, prolonging the first set time, and closing the furnace cover 7, wherein the first set time is 8-12 min.
And 4, step 4: and introducing nitrogen for a second set time, wherein the flow rate of the nitrogen is at least 1 time of the volume of the hearth. The second set time is 1 hour or more. And ensuring that the furnace pressure is within a set pressure numerical range; the pressure value range is set to 200-400 Pa.
And 5: the main control temperature is controlled within a second set temperature range, and the second set temperature range is 860-950 ℃. And (3) introducing methanol and propane, reducing the carbon potential CP to 0.75-0.85%, and keeping the saturated carburization for a third set time. The flow ratio of the nitrogen to the methanol is 1: 1-1.2: 1. The third setting time is 2 h.
The carbon potential reduction time of the muffle tank-free carbon saturation control process is reduced from conventional 1-3h to 1h shown in figure 1, so that the production and heating cost is greatly reduced; the dispersion degree and reliability of the carburized carbon concentration of the carburized part are improved, the dispersion degree of the conventional 1-4-grade carbide is improved to a stable state 1 grade shown in figure 3, and the quality and the dispersion degree of the product are greatly improved.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be able to cover the technical scope of the present invention and the equivalent alternatives or modifications according to the technical solution and the inventive concept of the present invention within the technical scope of the present invention.
Claims (10)
1. A muffle-tank-free carbon saturation control process is characterized by comprising the following steps:
the muffle-free tank comprises a furnace shell (6) and a furnace cover (7) positioned above the furnace shell (6), wherein a furnace lining (1) is arranged inside the furnace shell (6);
the method comprises the following steps:
step 1: heating a hearth, and closing nitrogen, methanol and propane during heating;
step 2: the main control temperature of the area below the furnace cover (7) is increased to a first set temperature range, the furnace cover (7) is opened upwards, the opening stroke of the furnace cover (7) is smaller than the full opening stroke, carbon burning is carried out, and nitrogen, methane and propane are closed during the carbon burning period;
and step 3: keeping the main control temperature in a first set temperature range, continuing to heat until the temperature of the area inside the furnace lining (1) reaches a peak value and begins to drop, prolonging the first set time after the peak value is reached, and closing the furnace cover (7);
and 4, step 4: introducing nitrogen to keep the second set time and ensure that the furnace pressure is in the set pressure numerical range;
and 5: and controlling the main control temperature within a second set temperature range, introducing methanol and propane, and keeping saturated carburization for a third set time after the carbon potential is reduced to a target value.
2. The muffle tank-free carbon saturation control process of claim 1, wherein: the first set temperature range is 930-950 ℃.
3. The muffle tank-free carbon saturation control process of claim 1, wherein: the first setting time is 8-12 min.
4. The muffle tank-free carbon saturation control process of claim 1, wherein: the second set time is 1 hour or more.
5. The muffle tank-free carbon saturation control process of claim 1, wherein: the pressure value range is set to 200-400 Pa.
6. The muffle tank-free carbon saturation control process of claim 1, wherein: the second set temperature range is 860-950 ℃.
7. The muffle tank-free carbon saturation control process of claim 1, wherein: the nitrogen flow is at least 1 furnace volume.
8. The muffle tank-free carbon saturation control process of claim 1, wherein: the flow ratio of the nitrogen to the methanol is 1: 1-1.2: 1.
9. The muffle tank-free carbon saturation control process of claim 1, wherein: the third setting time is 2 h.
10. The muffle tank-free carbon saturation control process of claim 1, wherein: in step 5, the carbon potential CP is reduced to 0.75-0.85%.
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| CN202110416053.1A CN113215519B (en) | 2021-04-19 | 2021-04-19 | Carbon saturation control process of muffle-free tank |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4769090A (en) * | 1985-08-14 | 1988-09-06 | L'air Liquide | Rapid carburizing process in a continuous furnace |
| CN101058865A (en) * | 2007-05-30 | 2007-10-24 | 太原理工大学 | Supersaturated carburizing steel |
| CN105369260A (en) * | 2015-11-19 | 2016-03-02 | 张家港市广大机械锻造有限公司 | Carburizing heat treatment technique for 8620H gear steel |
| CN106756756A (en) * | 2016-12-14 | 2017-05-31 | 常州天山重工机械有限公司 | A kind of raising carburizing part case hardness, the technique of control surface tissue dispersion degree |
| CN108251787A (en) * | 2018-01-23 | 2018-07-06 | 南京科达新控仪表有限公司 | A kind of carbo-nitriding automatic control system |
-
2021
- 2021-04-19 CN CN202110416053.1A patent/CN113215519B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4769090A (en) * | 1985-08-14 | 1988-09-06 | L'air Liquide | Rapid carburizing process in a continuous furnace |
| CN101058865A (en) * | 2007-05-30 | 2007-10-24 | 太原理工大学 | Supersaturated carburizing steel |
| CN105369260A (en) * | 2015-11-19 | 2016-03-02 | 张家港市广大机械锻造有限公司 | Carburizing heat treatment technique for 8620H gear steel |
| CN106756756A (en) * | 2016-12-14 | 2017-05-31 | 常州天山重工机械有限公司 | A kind of raising carburizing part case hardness, the technique of control surface tissue dispersion degree |
| CN108251787A (en) * | 2018-01-23 | 2018-07-06 | 南京科达新控仪表有限公司 | A kind of carbo-nitriding automatic control system |
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| CN113215519B (en) | 2023-08-15 |
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