CN114196809A - Method for reducing heating decarburization of steel billet - Google Patents
Method for reducing heating decarburization of steel billet Download PDFInfo
- Publication number
- CN114196809A CN114196809A CN202111573923.2A CN202111573923A CN114196809A CN 114196809 A CN114196809 A CN 114196809A CN 202111573923 A CN202111573923 A CN 202111573923A CN 114196809 A CN114196809 A CN 114196809A
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- Prior art keywords
- temperature
- heating
- section
- soaking section
- nitrogen
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Classifications
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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
- C21D1/76—Adjusting the composition of the atmosphere
-
- 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
-
- 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
- C21D9/70—Furnaces for ingots, i.e. soaking pits
Abstract
The invention discloses a method for reducing heating decarburization of a steel billet, which is implemented according to the following steps: 1) designing and arranging a set of nitrogen pipeline, introducing nitrogen into a gas burner of a soaking section of the heating furnace, uniformly arranging the nitrogen in the soaking section, and adding 2 sets of air extraction type flue gas analyzers in the soaking section; 2) a pipeline main valve, a pressure reducing valve and a pneumatic regulating valve are arranged on the newly added nitrogen pipeline; 3) a nitrogen nozzle is additionally arranged at the side of the gas burner of the soaking section, so that nitrogen uniformly enters the hearth of the soaking section; 4) and optimizing the heating process system of the temperature of the soaking section of the heating furnace and the atmosphere in the heating furnace in the rolling stop state. The invention can forcibly adjust the atmosphere in the heating furnace, and combines reasonable heating parameter control, thereby effectively reducing the thickness of surface decarburization during billet heating and improving the overall performance of steel.
Description
Technical Field
The invention relates to a method for reducing heating decarburization of a steel billet.
Background
Background art 1: when steel rolling production is carried out in a steel plant, a steel billet needs to be heated in a heating furnace, and when the steel billet is heated to a certain temperature, carbon on the surface layer of the steel billet reacts with media such as oxygen, hydrogen, carbon monoxide, water vapor and the like in the furnace, so that the carbon concentration on the surface layer of the steel billet is reduced, and the phenomenon is called decarburization. When the thickness of the decarburized layer on the steel surface is large, the quenching hardness, the fatigue strength and the wear resistance of the steel are reduced, and the performance of the steel is greatly influenced.
Background art 2: the steel billet can be decarbonized in the heating process, and medium-high carbon steel is particularly obvious and is mainly influenced by three aspects of heating temperature, heating time and furnace atmosphere. The decarburization mainly occurs in the period when the billet is heated to over 1050 ℃ (namely the billet is stepped to the soaking section of the heating furnace), the residence time of the billet in the soaking section in the continuous rolling state is short, the decarburization is not obvious, and the residence time of the billet in the soaking section in the accident state is long, and the decarburization is serious. The key point of controlling decarburization is to control the heating temperature of the billet in a soaking section and the furnace atmosphere in an accident state.
Background art 3: at present, steel rolling heating furnaces of domestic steel and iron plants adopt a heating mode that coal gas or natural gas is used as fuel and air is used as combustion improver. In order to ensure sufficient combustion, the air-fuel ratio is basically controlled at a fixed value, and the air quantity cannot be adjusted to control the atmosphere in the heating furnace.
And (3) searching documents: (1) decarburization simulation study in the billet heating process, zhinjing, songxiang, lismingjie, chenhaigunn; (2) a test method for obtaining surface decarburization in a steel billet heating process of a steel rolling heating furnace comprises the steps of obtaining Thangsie, Chenhongxu and Caoxin Sichuan continents; (3) research and prediction of oxidation and decarburization in the heating process of M2 steel, and Song enhancement; as is apparent from the above search documents, the current methods for controlling the thickness of the decarburized layer mainly focus on controlling the steel-making composition and improving the heating temperature, and there is no document relating to the reduction of the thickness of the decarburized layer by forcibly adjusting the furnace atmosphere in the soaking zone of the heating furnace.
Disclosure of Invention
The invention aims to provide a method for reducing heating decarburization of a steel billet, which can forcibly adjust the atmosphere in a heating furnace and effectively reduce the thickness of surface decarburization during heating of the steel billet by combining reasonable heating parameter control, thereby improving the overall performance of steel.
The invention adopts the technical scheme that the method for reducing the heating decarburization of the steel billet is implemented according to the following steps: 1) designing and arranging a set of nitrogen pipeline, introducing nitrogen into a coal gas burner of a soaking section of a heating furnace, uniformly arranging the nitrogen in the soaking section, adding 2 sets of air extraction type flue gas analyzers in the soaking section, and aligning the soaking sectionIn the segmental hearth O2And the CO concentration is monitored rapidly, continuously and in real time; 2) a pipeline main valve, a pressure reducing valve and a pneumatic regulating valve are arranged on the newly added nitrogen pipeline; 3) a nitrogen nozzle is additionally arranged at the side of the gas burner of the soaking section, so that nitrogen uniformly enters the hearth of the soaking section; 4) optimizing the heating process system of the temperature of the soaking section of the heating furnace and the atmosphere in the heating furnace in the rolling stop state:
| waiting time for rolling | Cooling and heat preservation requirements | Time of temperature rise in advance |
| ≤30 min | The temperature of the soaking section is not reduced, and the temperature of the heating section is reduced by 30 DEG C | |
| 30～60 min | The temperature of the heating section and the soaking section is controlled below 1100 DEG C | |
| 1～2 h | The first 0.5 hour, the temperature of the heating section and the soaking section is controlled to be less than or equal to 1050 ℃, subsequent heat preservation according to the temperature of less than or equal to 1050 DEG C | After 0.5 hour, raising the temperature of the soaking section and the heating section to less than or equal to 1150 DEG C |
| 2～4 h | The first 0.5 hour, the temperature of the heating section and the soaking section is controlled to be less than or equal to 1000 ℃, the subsequent pressing is less than or equal toKeep the temperature at 1000 DEG C | After 1 hour, raising the temperature of the soaking section and the heating section to be less than or equal to 1150 DEG C |
| 4～8 h | The first 0.5 hour, the temperature of the heating section and the soaking section is controlled to be less than or equal to 950 ℃, and then Keeping the temperature of less than or equal to 950 DEG C | After 1 hour, raising the temperature of the soaking section and the heating section to be less than or equal to 1150 DEG C |
| ＞8h | The temperature of the heating section and the soaking section is controlled to be less than or equal to 800 ℃ in the first 1 hour, and the temperature of the subsequent heating section and the soaking section is controlled to be less than or equal to 800 DEG C Keeping the temperature at 800 ℃ or below | After receiving the temperature raising instruction, raising the temperature 3 hours in advance to below 1050, and waiting for rolling The time is controlled to be 1 h-2 h |
Control was performed according to the procedure in the table above.
When a fault is met in the rolling process, the walking beam of the heating furnace stops tapping, a part of billets can be retained in the soaking section at the moment, the heating temperature of the billets passing through the heating section is higher, and the retention time in the soaking section is longer, the C on the surface of the steel and the O in the furnace2Reacts with CO and other media to cause the decarburization of the steel surface. The invention uniformly fills nitrogen into the furnace chamber of the soaking section through the designed nitrogen pipe network in the accident stop state. Monitoring of in-furnace O by flue gas analyzer2And the CO concentration, the flow of the nitrogen is controlled by a pneumatic regulating valve, and the hearth atmosphere is controlled in a reducing atmosphere. Reduction of C and O2And CO and the like, thereby relieving the occurrence of decarburization. The method can effectively reduce the thickness of the decarburized layer during the heating of the steel billet and solve the problem of unqualified steel performance caused by decarburization. The invention is more suitable for medium and high carbon high-quality special steel production lines, has simple process adjustment and better popularization.
Detailed Description
A method for reducing heating decarburization of a steel billet is implemented according to the following steps: 1) designing and arranging a set of nitrogen pipeline, introducing nitrogen into a gas burner of a soaking section of a heating furnace to ensure that the nitrogen is uniformly arranged at the soaking section, adding 2 sets of air extraction type flue gas analyzers at the soaking section, and carrying out O treatment on the inside of a hearth of the soaking section2And the CO concentration is monitored rapidly, continuously and in real time; 2) a pipeline main valve, a pressure reducing valve and a pneumatic regulating valve are arranged on the newly added nitrogen pipeline; 3) a nitrogen nozzle is additionally arranged at the side of the gas burner of the soaking section, so that nitrogen uniformly enters the hearth of the soaking section; 4) optimizing the heating process system of the temperature of the soaking section of the heating furnace and the atmosphere in the heating furnace in the rolling stop state:
| waiting time for rolling | Cooling and heat preservation requirements | Time of temperature rise in advance |
| ≤30 min | The temperature of the soaking section is not reduced, and the temperature of the heating section is reduced by 30 DEG C | |
| 30～60 min | The temperature of the heating section and the soaking section is controlled below 1100 DEG C | |
| 1～2 h | The first 0.5 hour, the temperature of the heating section and the soaking section is controlled to be less than or equal to 1050 ℃, subsequent heat preservation according to the temperature of less than or equal to 1050 DEG C | After 0.5 hour, raise the temperature, allThe temperature of the hot section and the heating section is raised to be less than or equal to 1150 DEG C |
| 2～4 h | The first 0.5 hour, the temperature of the heating section and the soaking section is controlled to be less than or equal to 1000 ℃, subsequent heat preservation according to the temperature of less than or equal to 1000 DEG C | After 1 hour, raising the temperature of the soaking section and the heating section to be less than or equal to 1150 DEG C |
| 4～8 h | The first 0.5 hour, the temperature of the heating section and the soaking section is controlled to be less than or equal to 950 ℃, and then Keeping the temperature of less than or equal to 950 DEG C | After 1 hour, raising the temperature of the soaking section and the heating section to be less than or equal to 1150 DEG C |
| ＞8h | The temperature of the heating section and the soaking section is controlled to be less than or equal to 800 ℃ in the first 1 hour, and the temperature of the subsequent heating section and the soaking section is controlled to be less than or equal to 800 DEG C Keeping the temperature at 800 ℃ or below | After receiving the temperature raising instruction, raising the temperature 3 hours in advance to below 1050, and waiting for rolling The time is controlled to be 1 h-2 h |
Control was performed according to the procedure in the table above.
Claims (1)
1. A method for reducing heating decarburization of a steel billet is implemented according to the following steps: 1) designing and arranging a set of nitrogen pipeline, introducing nitrogen into a gas burner of a soaking section of a heating furnace to ensure that the nitrogen is uniformly arranged at the soaking section, adding 2 sets of air extraction type flue gas analyzers at the soaking section, and carrying out O treatment on the inside of a hearth of the soaking section2And the CO concentration is monitored rapidly, continuously and in real time; 2) a pipeline main valve, a pressure reducing valve and a pneumatic regulating valve are arranged on the newly added nitrogen pipeline; 3) a nitrogen nozzle is additionally arranged at the side of the gas burner of the soaking section, so that nitrogen uniformly enters the hearth of the soaking section; 4) optimizing the temperature of the soaking section of the heating furnace in the rolling stop stateAnd a heating process system of furnace atmosphere:
Control was performed according to the procedure in the table above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111573923.2A CN114196809A (en) | 2021-12-21 | 2021-12-21 | Method for reducing heating decarburization of steel billet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111573923.2A CN114196809A (en) | 2021-12-21 | 2021-12-21 | Method for reducing heating decarburization of steel billet |
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| Publication Number | Publication Date |
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| CN114196809A true CN114196809A (en) | 2022-03-18 |
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| CN202111573923.2A Pending CN114196809A (en) | 2021-12-21 | 2021-12-21 | Method for reducing heating decarburization of steel billet |
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| CN (1) | CN114196809A (en) |
Citations (12)
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| JPH02247328A (en) * | 1989-03-18 | 1990-10-03 | Nippon Steel Corp | Walking beam-type heating furnace for material to be rolled |
| JPH0390517A (en) * | 1989-09-01 | 1991-04-16 | Kawasaki Steel Corp | Method for heating silicon-containing steel slab at high temperature |
| DE3868015D1 (en) * | 1987-11-17 | 1992-03-05 | Air Liquide | METHOD FOR HEAT TREATMENT IN A GAS ATMOSPHERE BASED ON NITROGEN AND HYDROCARBON. |
| JP2872404B2 (en) * | 1989-05-08 | 1999-03-17 | 川崎製鉄株式会社 | Method for producing unidirectional silicon steel sheet with excellent magnetic properties |
| US20030131912A1 (en) * | 2000-02-04 | 2003-07-17 | Yannick Rancon | Method and apparatus for controlling the decarburization of steel components in a furnace |
| CN101886159A (en) * | 2010-07-13 | 2010-11-17 | 贾会平 | Method and device for heating steel billet |
| CN205062128U (en) * | 2015-07-29 | 2016-03-02 | 西安市北恒实业有限公司 | Heat treating complete protective atmosphere's of no hydrogen preparation facilities |
| CN106282533A (en) * | 2015-05-27 | 2017-01-04 | 宝山钢铁股份有限公司 | A kind of temperature-controlled process to be rolled of heating furnace |
| CN110612359A (en) * | 2017-05-11 | 2019-12-24 | 杰富意钢铁株式会社 | Method for producing hot-dip galvanized steel sheet |
| TWI697563B (en) * | 2019-09-26 | 2020-07-01 | 中國鋼鐵股份有限公司 | Billet reheating furnace and method for inhibiting thickening of surface decarburization layer of billet |
| CN111850262A (en) * | 2020-06-22 | 2020-10-30 | 鞍钢蒂森克虏伯汽车钢有限公司 | Production method of ultra-low carbon baking hardening continuous hot-dip galvanized steel sheet |
| CN112899466A (en) * | 2021-02-08 | 2021-06-04 | 新疆八一钢铁股份有限公司 | Heating furnace control method for preventing spring steel from decarbonization |
-
2021
- 2021-12-21 CN CN202111573923.2A patent/CN114196809A/en active Pending
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3868015D1 (en) * | 1987-11-17 | 1992-03-05 | Air Liquide | METHOD FOR HEAT TREATMENT IN A GAS ATMOSPHERE BASED ON NITROGEN AND HYDROCARBON. |
| JPH02247328A (en) * | 1989-03-18 | 1990-10-03 | Nippon Steel Corp | Walking beam-type heating furnace for material to be rolled |
| JP2872404B2 (en) * | 1989-05-08 | 1999-03-17 | 川崎製鉄株式会社 | Method for producing unidirectional silicon steel sheet with excellent magnetic properties |
| JPH0390517A (en) * | 1989-09-01 | 1991-04-16 | Kawasaki Steel Corp | Method for heating silicon-containing steel slab at high temperature |
| US20030131912A1 (en) * | 2000-02-04 | 2003-07-17 | Yannick Rancon | Method and apparatus for controlling the decarburization of steel components in a furnace |
| CN101886159A (en) * | 2010-07-13 | 2010-11-17 | 贾会平 | Method and device for heating steel billet |
| CN106282533A (en) * | 2015-05-27 | 2017-01-04 | 宝山钢铁股份有限公司 | A kind of temperature-controlled process to be rolled of heating furnace |
| CN205062128U (en) * | 2015-07-29 | 2016-03-02 | 西安市北恒实业有限公司 | Heat treating complete protective atmosphere's of no hydrogen preparation facilities |
| CN110612359A (en) * | 2017-05-11 | 2019-12-24 | 杰富意钢铁株式会社 | Method for producing hot-dip galvanized steel sheet |
| TWI697563B (en) * | 2019-09-26 | 2020-07-01 | 中國鋼鐵股份有限公司 | Billet reheating furnace and method for inhibiting thickening of surface decarburization layer of billet |
| CN111850262A (en) * | 2020-06-22 | 2020-10-30 | 鞍钢蒂森克虏伯汽车钢有限公司 | Production method of ultra-low carbon baking hardening continuous hot-dip galvanized steel sheet |
| CN112899466A (en) * | 2021-02-08 | 2021-06-04 | 新疆八一钢铁股份有限公司 | Heating furnace control method for preventing spring steel from decarbonization |
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