CN112359314A - Carbonitriding method for refractory mold - Google Patents
Carbonitriding method for refractory mold Download PDFInfo
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- CN112359314A CN112359314A CN202011090973.0A CN202011090973A CN112359314A CN 112359314 A CN112359314 A CN 112359314A CN 202011090973 A CN202011090973 A CN 202011090973A CN 112359314 A CN112359314 A CN 112359314A
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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
- C23C8/28—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 more than one element being applied in one step
- C23C8/30—Carbo-nitriding
- C23C8/32—Carbo-nitriding of ferrous surfaces
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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
- 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
- C21D11/00—Process control or regulation for heat treatments
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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
- C21D9/0068—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for particular articles not mentioned below
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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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- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
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- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
The invention relates to a carbonitriding method for a refractory mold, which comprises the following steps: (1) firstly, processing a single refractory mould into a designed shape, and putting the refractory mould with the cleaned surface into a carburizing furnace; (2) heating the carburizing furnace, dripping ethanol at the speed of 200 drops/minute, and simultaneously introducing ammonia gas at the speed of 200L/h for exhausting until the gas in the carburizing furnace is qualified; (3) continuously heating to 870-; the surface strengthening performance of the die is high, the service life is long, the method can be suitable for 1000 tons or less of pressing machines and various refractory pug dies, and the applicability is stronger.
Description
Technical Field
The invention relates to the technical field of mold manufacturing, in particular to a carbonitriding method for a refractory mold.
Background
The refractory product mold is a single combined mold used for producing refractory product blank and punch forming, the pressure of most punching machines is 360-1000 tons, and the main component of the refractory product pug is granular typical oxide (such as Al)2O3、SiO2MgO, etc.), SiC, SiN, coal and aluminum coal, the Mohs hardness of the refractory product is equal to Rockwell hardness of 50-57 HRC, the granularity is 0.5-3 mm, and the refractory product is polygonal, and in the service process, the refractory product mold not only needs to bear the side pressure of a large-tonnage press through mud material extrusion conduction, but also needs to bear the abrasion of high-stress excavation type hard particles generated in the stamping and forming processes, and the service condition is severe, so that the refractory product mold has enough strength and abrasion resistance on the surface and also has certain toughness, and the main failure form of the service of the mold is excavation abrasion and fracture.
The Q235B steel is generally used for manufacturing refractory product moulds due to low price, surface strengthening is carried out through chemical heat treatment so as to meet the requirement of service performance, and in the chemical heat treatment, carburization treatment is most widely applied and is characterized in that the deep layer is thick and has certain compressive strength and hardness, but the wear resistance can not meet the requirement; the wear resistance and fatigue resistance of nitriding treatment are superior to those of carburizing, but the production period is long and the depth is thin, so the nitriding treatment is basically not suitable for strengthening a refractory product mold; the carbonitriding treatment has the advantages of both carburizing and nitriding and is also applied more.
In the prior art, because the refractory material mould adopts one-stage type co-infiltration, the deep hardened layer and the high wear resistance are difficult to be considered in a certain production period.
Disclosure of Invention
In view of the above, the present invention is directed to a carbonitriding method for a refractory mold, so as to solve the problem that the existing refractory mold is difficult to have both a deep hardened layer and high wear resistance in a certain production period due to one-stage carbonitriding.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a carbonitriding method for a refractory mold comprising the steps of:
(1) firstly, processing a single refractory mould into a designed shape, and putting the refractory mould with the cleaned surface into a carburizing furnace;
(2) heating the carburizing furnace, dripping ethanol at the speed of 200 drops/minute, and simultaneously introducing ammonia gas at the speed of 200L/h for exhausting until the gas in the carburizing furnace is qualified;
(3) continuously heating to 870-890 ℃, preserving the temperature for 5-8h at 870-890 ℃, dripping kerosene at 160 drops/min at the speed of 140-890 ℃, introducing ammonia gas at 220L/h at the speed of 180-890 ℃, and preserving the temperature for 5-8h at 870-890 ℃;
(4) cooling to 820-;
(5) continuously cooling to 750 ℃ within 3-5h, dripping ethanol at the speed of 50-70 drops/min during the cooling, and introducing ammonia gas at the speed of 420L/h;
(6) and putting the refractory mold into 8-10% salt solution for quenching, controlling the temperature to be less than or equal to 40 ℃, and preserving the temperature of the quenched workpiece for 2-4h at the temperature of 150-180 ℃.
Preferably, CO is used in said step (2)2＜0.5﹪、O2And < 0.4% of the gas in the furnace is qualified.
Preferably, the step (4) comprises the step 1, wherein the temperature reduction stage is from 880 ℃ to 820-840 ℃ for 1.5-2h, and the temperature is constant at 820-840 ℃ for 1.5-2 h.
Preferably, the step (5) comprises a temperature reduction stage from 820-840 ℃ to 730-750 ℃ for a time period of 2h, and a constant temperature at 820-840 ℃ for a time period of 2 h.
Compared with the prior art, the carbonitriding method for the refractory mold has the following advantages:
1. the method of high-temperature co-permeation, low-temperature co-permeation and diffusion three-section co-permeation is adopted to carry out carbonitriding on the refractory mould, the co-permeation layer is well combined with the matrix, the thickness of the co-permeation layer is large, and the use requirement of mould abrasion is completely met;
2. the surface strengthening performance of the die is high, the service life is long, the method can be suitable for 1000 tons of presses and below and various refractory pug dies, and the applicability is stronger;
drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments of the present invention will be briefly described below. Wherein the drawings are only for purposes of illustrating some embodiments of the invention and are not to be construed as limiting the invention to all embodiments thereof.
FIG. 1 is a graph showing the relationship between the processing temperature and the processing time in each step in the fourth embodiment of the present invention.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
The first embodiment is as follows:
a carbonitriding method for a refractory mold comprising the steps of:
(1) firstly, processing a single refractory mould into a designed shape, and putting the refractory mould with the cleaned surface into a carburizing furnace;
(2) heating the carburizing furnace, dripping ethanol at the speed of 200 drops/minute, and simultaneously introducing ammonia gas at the speed of 200L/h for exhausting until the gas in the carburizing furnace is qualified;
(3) continuously heating to 870 ℃, dripping kerosene at the speed of 140 drops/min, introducing ammonia gas at the speed of 180L/h, and keeping the temperature for 5 h;
(4) cooling to 820 ℃ within 3h, dripping ethanol at the speed of 50 drops/min, dripping kerosene at the speed of 50 drops/min, and introducing ammonia gas at the speed of 330L/h;
(5) continuously cooling to 730 ℃ within 3h, dripping ethanol at the speed of 50 drops/min during cooling, and introducing ammonia gas at the speed of 380L/h;
(6) and putting the refractory mould into 8% salt water for quenching, controlling the temperature to be less than or equal to 40 ℃, and preserving the temperature of the quenched workpiece at 150 ℃ for 2 h.
Example two:
on the basis of the first embodiment, the carbonitriding method of the refractory mold of the first embodiment is further optimized:
a carbonitriding method for a refractory mold comprising the steps of:
(1) firstly, processing a single refractory mould into a designed shape, and putting the refractory mould with the cleaned surface into a carburizing furnace;
(2) heating the carburizing furnace, dripping ethanol at the speed of 200 drops/minute, and simultaneously introducing ammonia gas at the speed of 200L/h for exhausting until the gas in the carburizing furnace is qualified;
(3) continuously heating to 890 ℃, dripping kerosene at the speed of 160 drops/min, introducing ammonia gas at the speed of 220L/h, and keeping the temperature for 8 h;
(4) cooling to 840 ℃ within 4h, dripping ethanol at the speed of 70 drops/min, dripping kerosene at the speed of 70 drops/min, and introducing ammonia gas at the speed of 370L/h;
(5) continuously cooling to 750 ℃ within 5h, dripping ethanol at the speed of 70 drops/min, and introducing ammonia gas at the speed of 420L/h;
(6) and putting the refractory mould into 10% salt water for quenching, controlling the temperature to be less than or equal to 40 ℃, and preserving the temperature of the quenched workpiece at 180 ℃ for 4 hours.
Example three:
on the basis of the first embodiment, the carbonitriding method of the refractory mold of the first embodiment is further optimized:
a carbonitriding method for a refractory mold comprising the steps of:
(1) firstly, processing a single refractory mould into a designed shape, and putting the refractory mould with the cleaned surface into a carburizing furnace;
(2) heating the carburizing furnace, dripping ethanol at the speed of 200 drops/minute, and simultaneously introducing ammonia gas at the speed of 200L/h for exhausting until the gas in the carburizing furnace is qualified;
(3) continuously heating to 880 ℃, dripping kerosene at the speed of 150 drops/min, introducing ammonia gas at the speed of 200L/h, and keeping the temperature for 6 h;
(4) cooling to 830 ℃ within 3.5h, dripping ethanol at the speed of 60 drops/min during cooling, dripping kerosene at the speed of 60 drops/min, and introducing ammonia gas at the speed of 350L/h;
(5) continuously cooling to 740 ℃ within 4h, dripping ethanol at the speed of 60 drops/min during cooling, and introducing ammonia gas at the speed of 400L/h;
(6) and putting the refractory mould into 9% edible salt water for quenching, controlling the temperature to be less than or equal to 40 ℃, and preserving the temperature of the quenched workpiece at 165 ℃ for 3 hours.
Example four:
on the basis of the first embodiment, the carbonitriding method of the refractory mold of the first embodiment is further optimized:
a carbonitriding method for a refractory mold comprising the steps of:
(1) firstly, processing a single refractory mould into a designed shape, and putting the refractory mould with the cleaned surface into a carburizing furnace;
(2) heating the carburizing furnace, dripping ethanol at the speed of 200 drops/minute, and simultaneously introducing ammonia gas at the speed of 200L/h for exhausting until the gas in the carburizing furnace is qualified;
(3) continuously heating to 880 ℃, dripping kerosene at the speed of 150 drops/min, introducing ammonia gas at the speed of 200L/h, and keeping the temperature for 6 h;
(4) uniformly heating the temperature in the carburizing furnace from 880 ℃ to 830 ℃ within 2h, preserving the heat at 830 ℃ for 1.5h, dripping ethanol at the speed of 60 drops/min during the temperature reduction period and the heat preservation period, dripping kerosene at the speed of 60 drops/min, and introducing ammonia gas at the speed of 350L/h;
(5) continuously cooling to 740 ℃ within 2h, preserving heat at 740 ℃ for 2h, dripping ethanol at the speed of 60 drops/min during the cooling period and the heat preservation period, and introducing ammonia gas at the speed of 400L/h;
(6) and putting the refractory mould into 9% edible salt water for quenching, controlling the temperature to be less than or equal to 40 ℃, and preserving the temperature of the quenched workpiece at 165 ℃ for 3 hours.
In the step (2), ethanol is selected and introduced in the phase of the schedulingAmmonia gas is generated by decomposing ethanol, the gas in the furnace is emptied, the ratio of the ethanol gas production to the methanol is slightly insufficient, the ammonia gas can be supplemented and exhausted in an accelerated manner, and the ethanol reaction formula is C2H5OH→[C]+CO+3H2The reaction formula of ammonia is 2NH3→N2+3H2，CO、H2Is a reducing gas, N2Inert gas can prevent oxidation of workpiece, and gas is taken out for assay and CO is checked after 2.5 hours of exhaust of carburizing furnace2、O2Percent of content when CO2＜0.5﹪、O2And (3) when the content is less than 0.4%, the atmosphere in the furnace is qualified, otherwise, the abnormity needs to be eliminated, the time is prolonged until the furnace gas is qualified, compared with the traditional method of adopting methanol, the methanol is toxic, personal injury can be caused by operation error, and the ethanol is harmless to a human body.
The step (3) is a high-temperature co-cementation process, the temperature in the step (3) is set to 880 ℃, carburization is mainly used, a small amount of ammonia gas is added while kerosene is dripped, carbon black can be reduced, infiltration of carbon atoms can be accelerated, compared with the traditional carburization, the common carburization temperature is 900-950 ℃, quenching of a workpiece with high temperature is easy to deform, and in addition, the temperature reduction in the early stage and the temperature reduction in the later stage are not beneficial to the subsequent carbonitriding.
The step (4) is a low-temperature co-cementation process, the kerosene is not fully decomposed at the temperature of below 850 ℃, a large amount of carbon black is easily generated, and the infiltration of activated carbon atoms is hindered, so that the dropping amount is reduced, and a small amount of weak carburizing agent ethanol is dropped; in addition, because the reduction of the temperature is beneficial to nitriding, the supply of ammonia gas is increased so as to increase the nitrogen concentration on the surface layer of the workpiece.
The step (5) is a diffusion stage, the absorption process is converted into a diffusion process, the overhigh carbon concentration on the surface caused by the high-temperature co-permeation stage is reduced to the required carbon concentration, the carbon concentration gradient tends to be smooth, and therefore the weak carburizing agent ethanol is dripped in; the further reduction of the temperature is more beneficial to the penetration of nitrogen atoms, so the supply of ammonia gas is increased, the nitrogen concentration on the surface of the refractory mould is increased, and the surface wear resistance of the refractory mould is enhanced.
The carbonitrided layers prepared in examples 1 to 5 were tested for thickness and hardness, and the results are shown in Table 1:
TABLE 1
| Carbonitriding layer thickness (mm) | Hardness (HRC) | |
| Example one | 1.17 | 62.8 |
| Example two | 1.22 | 63.5 |
| EXAMPLE III | 1.28 | 64.2 |
| Example four | 1.30 | 65.4 |
In the embodiment, the relationship between the treatment temperature and the treatment time in each step is shown in fig. 1, the hardness of the product of the refractory mold treated by the carbonitriding process in the embodiment can reach more than 62HRC, and the thickness of the co-carburized layer exceeds 1.17mm, so that the surface hardness and the wear resistance of the product are effectively improved.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (4)
1. A carbonitriding method for a refractory mold, comprising the steps of:
(1) firstly, processing a single refractory mould into a designed shape, and putting the refractory mould with the cleaned surface into a carburizing furnace;
(2) heating the carburizing furnace, dripping ethanol at the speed of 200 drops/minute, and simultaneously introducing ammonia gas at the speed of 200L/h for exhausting until the gas in the carburizing furnace is qualified;
(3) continuously heating to 870-890 ℃, preserving the temperature for 5-8h at 870-890 ℃, dripping kerosene at 160 drops/min at the speed of 140-890 ℃, introducing ammonia gas at 220L/h at the speed of 180-890 ℃, and preserving the temperature for 5-8h at 870-890 ℃;
(4) cooling to 820-;
(5) continuously cooling to 750 ℃ within 3-5h, dripping ethanol at the speed of 50-70 drops/min during the cooling, and introducing ammonia gas at the speed of 420L/h;
(6) and putting the refractory mold into 8-10% salt solution for quenching, controlling the temperature to be less than or equal to 40 ℃, and preserving the temperature of the quenched workpiece for 2-4h at the temperature of 150-180 ℃.
2. The carbonitriding method for a refractory mold as claimed in claim 1, wherein in the step (2), CO is introduced2＜0.5﹪、O2And < 0.4% of the gas in the furnace is qualified.
3. The carbonitriding method for a refractory mold as claimed in claim 2, wherein the step (4) comprises a temperature reduction step from 880 ℃ to 820 ℃ 840 ℃ for 1.5-2h, and a constant temperature at 820 ℃ 840 ℃ for 1.5-2 h.
4. The carbonitriding method for a refractory mold as claimed in claim 2, wherein the step (5) comprises a temperature reduction stage from 840 ℃ to 750 ℃ at 820-.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1563475A (en) * | 2004-03-13 | 2005-01-12 | 广东巨轮模具股份有限公司 | Five-element co-permeation surface strengthening treatment process and equipment for tire mold |
| CN101418451A (en) * | 2008-11-19 | 2009-04-29 | 郑州航空工业管理学院 | Carbonitriding-deep Re-B-C-N penetration composite heat treating process |
| CN105349940A (en) * | 2015-11-27 | 2016-02-24 | 陕西东铭车辆系统股份有限公司 | Carburizing and carbonitriding combined heat treatment method for hot forging marking die steel |
| WO2016027207A1 (en) * | 2014-08-18 | 2016-02-25 | Bharat Forge Limited | A method of hardening die surfaces |
-
2020
- 2020-10-13 CN CN202011090973.0A patent/CN112359314A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1563475A (en) * | 2004-03-13 | 2005-01-12 | 广东巨轮模具股份有限公司 | Five-element co-permeation surface strengthening treatment process and equipment for tire mold |
| CN101418451A (en) * | 2008-11-19 | 2009-04-29 | 郑州航空工业管理学院 | Carbonitriding-deep Re-B-C-N penetration composite heat treating process |
| WO2016027207A1 (en) * | 2014-08-18 | 2016-02-25 | Bharat Forge Limited | A method of hardening die surfaces |
| CN105349940A (en) * | 2015-11-27 | 2016-02-24 | 陕西东铭车辆系统股份有限公司 | Carburizing and carbonitriding combined heat treatment method for hot forging marking die steel |
Non-Patent Citations (1)
| Title |
|---|
| 王祺: "耐火材料成型模具的气体碳氮共渗", 《耐火材料》 * |
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