CN112647017A - Method for controlling inclusions in gear steel - Google Patents
Method for controlling inclusions in gear steel Download PDFInfo
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- CN112647017A CN112647017A CN202011374063.5A CN202011374063A CN112647017A CN 112647017 A CN112647017 A CN 112647017A CN 202011374063 A CN202011374063 A CN 202011374063A CN 112647017 A CN112647017 A CN 112647017A
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- steel
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- gear steel
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/116—Refining the metal
- B22D11/117—Refining the metal by treating with gases
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/072—Treatment with gases
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/20—Ferrous alloys, e.g. steel alloys containing chromium with copper
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
-
- 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
- Y02P10/20—Recycling
Abstract
The invention discloses an inclusion control method for gear steel, which adopts a production process of converter smelting → LF refining → RH refining → square billet continuous casting → heating and rolling, taking 20CrMo gear steel as an example. According to the inclusion control method for the gear steel, the refining temperature, the RH refining time and the soft argon blowing time are well controlled, argon sealing protection casting is performed in the whole continuous casting process, nitrogen increase caused by contact of molten steel with air is prevented, and meanwhile, the titanium alloy addition amount of the titanium-containing gear steel is reduced, so that the purpose of reducing the precipitation concentration product of titanium nitride is achieved, the impurity content of the gear steel is greatly reduced, the gear steel is better than the quality of the conventional gear steel, and on the basis of theoretical simulation calculation, a proper continuous casting process is formulated through reasonable design of chemical element contents such as C, Mn and Cr which have great influence on hardenability, so that the element segregation degree is reduced, and the narrow-band homogenization and control of the elements are ensured.
Description
Technical Field
The invention relates to the technical field of special steel manufacturing, in particular to an inclusion control method for gear steel.
Background
Gear steel is a generic term for steels that can be used to machine and manufacture gears, and generally includes low carbon steels such as 20# steel, low carbon alloy steels such as: 20Cr, 20CrMnTi, etc., medium carbon steel: 35# steel, 45# steel, and the like, medium carbon alloy steel: 40Cr, 42CrMo, 35CrMo, etc., which are all called gear steels, are generally heat-treated according to the use requirements to have good strength, hardness and toughness, or have wear-resistant surface and good toughness and impact resistance in the core.
The existing gear steel has special purpose, the performance requirement is extremely strict, the gear is in an operating state, the gear steel has strong fatigue strength resistance because the tooth root part is obviously subjected to the action of bending stress, and the surface metal is easy to peel off or the tooth root is easy to break, and the high-quality gear steel has high requirement on purity in order to ensure the performance, so that the inclusions in the steel must be strictly controlled for producing the high-quality gear steel, and the main problem of reducing oxide inclusions in the steel is that the content of T in the steel is strictly controlled, therefore, the invention provides an inclusion control method of the gear steel.
Disclosure of Invention
Technical problem to be solved
Aiming at the defects of the prior art, the invention provides an inclusion control method for gear steel, which solves the problems in the background technology.
(II) technical scheme
In order to achieve the purpose, the invention provides the following technical scheme: the inclusion control method of the gear steel adopts the production process of converter smelting → LF refining → RH refining → square billet continuous casting → heating and rolling, taking 20CrMo gear steel as an example, the internal components and the weight percentages thereof are respectively as follows: cr: 1% -1.2%, Mo: 0.05% -0.15%, C: 0.30% -0.4%, Mn: 0.7% -0.8%, S: 0.01% -0.03%, Cu: 0.1% -0.2%, Al: 0.03% -0.4%, B: 0.0001% -0.0003%, Si: 0.2% -0.4%, and the specific production operation is as follows:
the first step is as follows: smelting by using converter
Taking the components and the weight ratio thereof as reference contrast, selecting a proper amount of materials, then putting the materials into a 150t oxygen top-bottom combined blown converter for smelting, adding molten iron, scrap steel and low-nitrogen alloy into the converter, strictly controlling a terminal point C to be 0.05-0.1% for molten steel obtained subsequently, tapping and deslagging to finally obtain a molten steel ladle;
the second step is that: performing LF refining
Hoisting the obtained ladle to an LF furnace station by using the conventional hoisting equipment, and refining the molten steel in the ladle;
the third step: carrying out RH refining
Continuously hoisting the ladle which finishes LF refining to a station for steelmaking of RH refining by using the existing hoisting equipment, then carrying out vacuum degassing treatment on the molten steel, wherein the treatment time is more than twenty minutes below the vacuum degree of less than 0.26kPa, feeding a calcium-silicon wire for calcium treatment after the vacuum treatment is finished, then carrying out weak stirring and sedation, controlling the soft argon blowing time to be more than eighteen minutes, and ensuring that impurities are fully floated;
the fourth step: (ii) a Continuous casting of square billet
Hoisting a molten steel ladle refined by RH to a continuous casting platform, adopting superheat degree continuous casting and constant casting speed which are more than forty-five degrees, carrying out whole-process argon protection casting on the molten steel by utilizing a crystallizer electromagnetic stirring technology, a liquid level automatic control technology and argon, and after the whole-process argon protection casting is finished, hoisting and stacking a steel billet for slow cooling treatment or red conveying for heating and rolling;
the fifth step: heating and rolling to obtain finished steel product
And heating the casting blank or the red steel billet subjected to slow cooling treatment at the temperature of one thousand to one hundred and ninety ℃ for more than two hundred and ten minutes, discharging the steel billet out of the furnace, descaling to ensure that the scale on the surface of the steel billet is completely removed, and rolling by using a rolling mill to obtain the 20CrMo gear steel with low impurity content.
Preferably, in the first step, a converter is used for smelting, a slag blocking cone is used for tapping and blocking slag, and aluminum, ferroalloy and slag charge are added into molten steel in the steel smelting process to perform deoxidation and slagging pre-refining.
Preferably, in the LF refining process in the second step, a sulfur wire is fed before RH vacuum treatment, and the S content is adjusted to be in a range of 0.01-0.03%.
Preferably, in the RH refining process in the third step, the argon pressure is controlled while the good fluidity of the slag of the steel ladle is ensured, the slag entrapment caused by the serious rolling of the molten steel is prevented, and the flow rate of the argon is 400-500 NL/min.
Preferably, the cooling intensity of the secondary cooling water used in the fourth step square billet continuous casting process is required to be more than 0.5L/Kg.
Preferably, in the fifth step, in the process of obtaining the semi-finished product steel material by heating and rolling, two-roller initial rolling and hot continuous rolling are adopted for rolling, the initial rolling temperature is 1100-.
(III) advantageous effects
The invention provides an inclusion control method for gear steel, which has the following beneficial effects:
according to the inclusion control method for the gear steel, the refining temperature, the RH refining time and the soft argon blowing time are well controlled, argon sealing protection casting is performed in the whole continuous casting process, nitrogen increase caused by contact of molten steel with air is prevented, and meanwhile, the titanium alloy addition amount of the titanium-containing gear steel is reduced, so that the purpose of reducing the precipitation concentration product of titanium nitride is achieved, the impurity content of the gear steel is greatly reduced, the gear steel is better than the quality of the conventional gear steel, and on the basis of theoretical simulation calculation, a proper continuous casting process is formulated through reasonable design of chemical element contents such as C, Mn and Cr which have great influence on hardenability, so that the element segregation degree is reduced, and the narrow-band homogenization and control of the elements are ensured.
Detailed Description
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.
The invention provides a technical scheme that: an inclusion control method of gear steel adopts a production process of converter smelting → LF refining → RH refining → square billet continuous casting → heating and rolling, taking 20CrMo gear steel as an example, the internal components and the weight percentages thereof are respectively as follows: cr: 1% -1.2%, Mo: 0.05% -0.15%, C: 0.30% -0.4%, Mn: 0.7% -0.8%, S: 0.01% -0.03%, Cu: 0.1% -0.2%, Al: 0.03% -0.4%, B: 0.0001% -0.0003%, Si: 0.2% -0.4%, and the specific production operation is as follows:
the first step is as follows: smelting by using converter
Taking the components and the weight ratio thereof as reference contrast, selecting a proper amount of materials, then putting the materials into a 150t oxygen top-bottom combined blown converter for smelting, adding molten iron, scrap steel and low-nitrogen alloy into the converter, strictly controlling a terminal point C to be 0.05-0.1% for molten steel obtained subsequently, tapping and slagging to finally obtain a ladle, in the first step, utilizing the converter to smelt, adopting a slag stopping cone to stop slag, and thinking that aluminum, iron alloy and slag charge are added into the molten steel for deoxidation and slagging pre-refining in the steel tapping process;
the second step is that: performing LF refining
Hoisting the obtained ladle to an LF furnace station by using the conventional hoisting equipment, refining molten steel in the ladle, feeding a sulfur wire before RH vacuum treatment in the LF refining process in the second step, and adjusting the S content to be in the range of 0.01-0.03%;
the third step: carrying out RH refining
Continuously hoisting the ladle which finishes LF refining to a station for steelmaking of RH refining by using the conventional hoisting equipment, then carrying out vacuum degassing treatment on the molten steel, wherein the treatment time is more than twenty minutes below the vacuum degree of less than 0.26kPa, feeding a calcium-silicon wire for calcium treatment after the vacuum treatment is finished, then carrying out weak stirring and sedation, controlling the soft argon blowing time to be more than eighteen minutes to ensure that impurities are fully floated, and controlling the argon pressure while ensuring good slag fluidity of the ladle in the RH refining process in the third step to prevent the slag from being rolled seriously due to the rolling of the molten steel, wherein the flow of the argon is 400-500 NL/min;
the fourth step: (ii) a Continuous casting of square billet
Hoisting a molten steel ladle refined by RH to a continuous casting platform, adopting superheat degree continuous casting and constant drawing speed which are more than forty-five degrees, and carrying out whole-process argon protection casting on the molten steel by utilizing a crystallizer electromagnetic stirring technology, a liquid level automatic control technology and argon, after the whole-process argon protection casting is finished, hoisting a steel billet to be stacked for slow cooling treatment or carrying out red sending for heating and rolling, wherein in the fourth step of square billet continuous casting, the cooling intensity of secondary cooling water used in the fourth step needs to be more than 0.5L/Kg;
the fifth step: heating and rolling to obtain finished steel product
And heating the casting blank or the red steel billet subjected to the slow cooling treatment, wherein the heating temperature ranges from one thousand to one hundred and ninety ℃ and the heating time is more than two hundred and ten minutes, descaling is carried out after the steel billet is discharged from a furnace to ensure that the scale on the surface of the steel billet is completely removed, and the 20CrMo gear steel with low impurity content is prepared after rolling by a rolling mill, in the fifth step of obtaining the semi-finished steel material by heating and rolling, a two-roller primary rolling and hot continuous rolling process is adopted for rolling, the primary rolling starting temperature is 1100-.
In conclusion, the inclusion control method for the gear steel has the advantages that the refining temperature, the RH refining time and the soft argon blowing time are well controlled, argon sealing protection casting is carried out in the whole continuous casting process, nitrogen increase caused by contact of molten steel with air is prevented, meanwhile, the titanium alloy addition amount of the titanium-containing gear steel is reduced, the purpose of reducing the titanium nitride precipitation concentration product is achieved, the impurity content of the gear steel is greatly reduced, the gear steel is better than the conventional gear steel in quality, on the basis of theoretical simulation calculation, through reasonable design of chemical element contents of C, Mn, Cr and the like which have great influence on hardenability, a proper continuous casting process is formulated to reduce the element segregation degree, and the narrow-band permeation and homogenization control of the elements is ensured.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (6)
1. A method for controlling inclusions in gear steel is characterized by comprising the following steps: the inclusion control method of the gear steel adopts the production process of converter smelting → LF refining → RH refining → square billet continuous casting → heating and rolling, taking 20CrMo gear steel as an example, the internal components and the weight percentages thereof are respectively as follows: cr: 1% -1.2%, Mo: 0.05% -0.15%, C: 0.30% -0.4%, Mn: 0.7% -0.8%, S: 0.01% -0.03%, Cu: 0.1% -0.2%, Al: 0.03% -0.4%, B: 0.0001% -0.0003%, Si: 0.2% -0.4%, and the specific production operation is as follows:
the first step is as follows: smelting by using converter
Taking the components and the weight ratio thereof as reference contrast, selecting a proper amount of materials, then putting the materials into a 150t oxygen top-bottom combined blown converter for smelting, adding molten iron, scrap steel and low-nitrogen alloy into the converter, strictly controlling a terminal point C to be 0.05-0.1% for molten steel obtained subsequently, tapping and deslagging to finally obtain a molten steel ladle;
the second step is that: performing LF refining
Hoisting the obtained ladle to an LF furnace station by using the conventional hoisting equipment, and refining the molten steel in the ladle;
the third step: carrying out RH refining
Continuously hoisting the ladle which finishes LF refining to a station for steelmaking of RH refining by using the existing hoisting equipment, then carrying out vacuum degassing treatment on the molten steel, wherein the treatment time is more than twenty minutes below the vacuum degree of less than 0.26kPa, feeding a calcium-silicon wire for calcium treatment after the vacuum treatment is finished, then carrying out weak stirring and sedation, controlling the soft argon blowing time to be more than eighteen minutes, and ensuring that impurities are fully floated;
the fourth step: (ii) a Continuous casting of square billet
Hoisting a molten steel ladle refined by RH to a continuous casting platform, adopting superheat degree continuous casting and constant casting speed which are more than forty-five degrees, carrying out whole-process argon protection casting on the molten steel by utilizing a crystallizer electromagnetic stirring technology, a liquid level automatic control technology and argon, and after the whole-process argon protection casting is finished, hoisting and stacking a steel billet for slow cooling treatment or red conveying for heating and rolling;
the fifth step: heating and rolling to obtain semi-finished steel material
And heating the casting blank or the red steel billet subjected to slow cooling treatment at the temperature of one thousand to one hundred and ninety ℃ for more than two hundred and ten minutes, discharging the steel billet out of the furnace, descaling to ensure that the scale on the surface of the steel billet is completely removed, and rolling by using a rolling mill to obtain the 20CrMo gear steel with low impurity content.
2. A method for controlling inclusions in a gear steel according to claim 1, characterized in that: in the first step, a converter is used for smelting, a slag blocking cone is used for tapping and blocking slag, and aluminum, ferroalloy and slag charge are added into molten steel during the steel smelting process to perform deoxidation and slagging pre-refining.
3. A method for controlling inclusions in a gear steel according to claim 1, characterized in that: and in the second step of LF refining, a sulfur wire is fed before RH vacuum treatment, and the S content is adjusted to be 0.01-0.03%.
4. A method for controlling inclusions in a gear steel according to claim 1, characterized in that: and in the RH refining process in the third step, the argon pressure is controlled while the good fluidity of the slag of the steel ladle is ensured, the slag entrapment caused by the serious rolling of the molten steel is prevented, and the flow of the argon is 400-500 NL/min.
5. A method for controlling inclusions in a gear steel according to claim 1, characterized in that: in the fourth step of square billet continuous casting process, the cooling intensity of the secondary cooling water used in the fourth step needs to be more than 0.5L/Kg.
6. A method for controlling inclusions in a gear steel according to claim 1, characterized in that: in the process of obtaining the semi-finished steel by heating and rolling in the fifth step, two-roller initial rolling and hot continuous rolling processes are adopted for rolling, wherein the initial rolling temperature is 1100-1145 ℃, and the final rolling temperature is 860-950 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011374063.5A CN112647017A (en) | 2020-11-30 | 2020-11-30 | Method for controlling inclusions in gear steel |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011374063.5A CN112647017A (en) | 2020-11-30 | 2020-11-30 | Method for controlling inclusions in gear steel |
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| CN112647017A true CN112647017A (en) | 2021-04-13 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115948689A (en) * | 2022-11-25 | 2023-04-11 | 中天钢铁集团有限公司 | Smelting method of ultra-high-clean sulfur-containing aluminum-containing steel |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS579860A (en) * | 1981-02-18 | 1982-01-19 | Daido Steel Co Ltd | Free cutting steel for high-performance gear and its manufacture |
| CN101191181A (en) * | 2006-11-24 | 2008-06-04 | 宝山钢铁股份有限公司 | Alloy steel for gear wheel and preparation method thereof |
| CN104212934A (en) * | 2014-09-10 | 2014-12-17 | 广东韶钢松山股份有限公司 | Control method for titanium nitride inclusion of gear steel bar material |
| CN104928582A (en) * | 2015-05-05 | 2015-09-23 | 广东韶钢松山股份有限公司 | 41Cr4 gear steel and production method thereof |
-
2020
- 2020-11-30 CN CN202011374063.5A patent/CN112647017A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS579860A (en) * | 1981-02-18 | 1982-01-19 | Daido Steel Co Ltd | Free cutting steel for high-performance gear and its manufacture |
| CN101191181A (en) * | 2006-11-24 | 2008-06-04 | 宝山钢铁股份有限公司 | Alloy steel for gear wheel and preparation method thereof |
| CN104212934A (en) * | 2014-09-10 | 2014-12-17 | 广东韶钢松山股份有限公司 | Control method for titanium nitride inclusion of gear steel bar material |
| CN104928582A (en) * | 2015-05-05 | 2015-09-23 | 广东韶钢松山股份有限公司 | 41Cr4 gear steel and production method thereof |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115948689A (en) * | 2022-11-25 | 2023-04-11 | 中天钢铁集团有限公司 | Smelting method of ultra-high-clean sulfur-containing aluminum-containing steel |
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Application publication date: 20210413 |