CN108971444B - Method for improving IF steel casting blank head blank quality - Google Patents
Method for improving IF steel casting blank head blank quality Download PDFInfo
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- CN108971444B CN108971444B CN201810713981.2A CN201810713981A CN108971444B CN 108971444 B CN108971444 B CN 108971444B CN 201810713981 A CN201810713981 A CN 201810713981A CN 108971444 B CN108971444 B CN 108971444B
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 51
- 239000010959 steel Substances 0.000 title claims abstract description 51
- 238000005266 casting Methods 0.000 title claims abstract description 49
- 238000000034 method Methods 0.000 title claims abstract description 28
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 30
- 239000002893 slag Substances 0.000 claims abstract description 30
- 238000009749 continuous casting Methods 0.000 claims abstract description 13
- 230000001133 acceleration Effects 0.000 claims abstract description 8
- 239000000843 powder Substances 0.000 claims description 8
- 230000004907 flux Effects 0.000 claims description 4
- 238000005520 cutting process Methods 0.000 abstract description 4
- 239000012535 impurity Substances 0.000 abstract description 3
- 230000003749 cleanliness Effects 0.000 description 8
- 230000015556 catabolic process Effects 0.000 description 7
- 238000006731 degradation reaction Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 239000002699 waste material Substances 0.000 description 7
- 238000012986 modification Methods 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- 238000005096 rolling process Methods 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 238000005304 joining Methods 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
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- 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
- B22D11/108—Feeding additives, powders, or the like
-
- 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
- B22D11/111—Treating the molten metal by using protecting powders
-
- 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
- B22D11/16—Controlling or regulating processes or operations
- B22D11/20—Controlling or regulating processes or operations for removing cast stock
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Continuous Casting (AREA)
Abstract
The invention discloses a method for improving the quality of a primary blank of an IF steel casting blank, which comprises the following steps: when the tonnage of the molten steel of the continuous casting tundish reaches 35 tons, adding a covering agent; placing casting slag and crystallizer covering slag on a crystallizer platform; controlling the pulling speed to be 0.2m/min after starting, then increasing to 0.4m/min, increasing the acceleration to be less than or equal to 0.05m/min2, and keeping for 30s +/-5 s; then the speed is increased from 0.4m/min to 0.8m/min, the increasing acceleration is 2 which is less than or equal to 0.05m/min, and the speed is kept for 30s +/-5 s. Through a series of measures such as reasonably controlling the adding time of the tundish covering agent, reasonably controlling the casting tonnage of the tundish, increasing the floating time of impurities, reasonably adding the casting slag and the covering slag in the crystallizer, optimizing the pulling speed during casting and the like, the slag inclusion of the coil can be well controlled within 4 meters of the head, the yield is improved, and the loss caused by overlong cutting length is reduced.
Description
Technical Field
The invention relates to the technical field of continuous casting, in particular to a method for improving the quality of a primary blank of an IF steel casting blank.
Background
The head billet is the first billet cast in a certain casting time in the continuous casting process, because liquid molten steel contacts air and a covering agent in a tundish when the continuous casting is started, the molten steel is oxidized, the oxygen content in the head billet is increased, meanwhile, the fluctuation of the liquid level of a flow field in a crystallizer is large when the continuous casting is started, the rolling of casting powder is easily caused, the slag rolling phenomenon is caused, the cleanliness of the molten steel of the head billet is poor, the quality cannot reach the quality of a normal billet, and therefore, the head billet can only be treated in a degradation or scrap mode, and the material waste is caused.
Disclosure of Invention
The application provides a method for improving the quality of a primary blank of an IF steel casting blank, and solves the technical problems that in the prior art, the cleanliness of molten steel of the primary blank is poor, the quality cannot reach the quality of a normal blank, and only the primary blank can be treated in a degradation or scrapping mode, so that the material waste is caused.
The application provides a method for improving the quality of a primary blank of an IF steel casting blank, which comprises the following steps:
when the tonnage of the molten steel of the continuous casting tundish reaches 35 tons, adding a covering agent;
placing casting slag and crystallizer covering slag on a crystallizer platform;
the speed of the pulling speed after starting is controlled to be 0.2m/min, then the pulling speed is increased to 0.4m/min, and the increasing acceleration is less than or equal to 0.05m/min2Keeping 30s +/-5 s; then the speed is increased from 0.4m/min to 0.8m/min, and the increasing acceleration is less than or equal to 0.05m/min2And keeping 30s +/-5 s.
Preferably, when the tonnage of the molten steel in the continuous casting tundish reaches 35 tons, adding a covering agent, comprising:
firstly, respectively adding part of the covering agent from the two stopper rod holes;
the remainder of the covering agent is then de-gated from the ladle of the tundish.
Preferably, the covering agent is 630 kg.
Preferably, the amount of the covering agent added from the two stopper rod holes is 120 kg. + -. 6kg respectively.
Preferably, the amount of the covering agent poured from the ladle of the tundish is 390kg + -6 kg.
Preferably, the placing of the casting slag and the mold flux on the mold platform comprises:
when the inflow amount of molten steel reaches 1/3-1/4 positions of a side hole of the submerged nozzle, adding casting slag;
when the inflow of molten steel reaches 100mm above a side hole of the submerged nozzle, 1/3 crystallizer casting powder is added;
when the casting speed is after starting, the residual 2/3 crystallizer casting powder is added.
Preferably, the casting slag is 5kg-10 kg.
Preferably, the mold flux is specifically 20kg to 30 kg.
Preferably, after the pulling speed is increased from 0.4m/min to 0.8m/min and is maintained for 30s +/-5 s, the method further comprises the following steps:
the pulling speed is increased from 0.8m/min to 1.2m/min and is kept for 30s +/-5 s.
Preferably, after the pulling speed is increased from 0.8m/min to 1.2m/min and is maintained for 30s + -5 s, the method further comprises:
the pulling speed is increased from 1.2m/min to the target pulling speed of 1.4 m/min.
The beneficial effect of this application is as follows:
through a series of measures of reasonably controlling the adding time of the tundish covering agent, reasonably controlling the casting tonnage of the tundish, increasing the floating time of impurities, reasonably adding the casting slag and the covering slag in the crystallizer, optimizing the pulling speed during casting and the like, the rolling slag can be well controlled to be mixed in the head part within 4 meters, the finished product quantity is improved, the loss caused by overlong cutting length is reduced, and the technical problem that the material waste is caused because the molten steel cleanliness of a head billet in the prior art is poor, the quality cannot reach the quality of a normal billet, and the head billet can only be treated in a degradation or scrapping mode due to the fact that the quality cannot reach the quality of the normal billet is solved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention.
FIG. 1 is a flow chart of a method of improving the quality of a primary blank of an IF steel casting blank provided herein;
FIG. 2 is a graph of pull rate variation at start of casting for the process of FIG. 1.
Detailed Description
The embodiment of the application provides a method for improving the quality of a primary blank of an IF steel casting blank, and solves the technical problems that in the prior art, the cleanliness of molten steel of the primary blank is poor, the quality cannot reach the quality of a normal blank, and only the primary blank can be treated in a degradation or scrapping mode, so that the material waste is caused.
In order to solve the technical problems, the general idea of the embodiment of the application is as follows:
through a series of measures of reasonably controlling the adding time of the tundish covering agent, reasonably controlling the casting tonnage of the tundish, increasing the floating time of impurities, reasonably adding the casting slag and the covering slag in the crystallizer, optimizing the pulling speed during casting and the like, the rolling slag can be well controlled to be mixed in the head part within 4 meters, the finished product quantity is improved, the loss caused by overlong cutting length is reduced, and the technical problem that the material waste is caused because the molten steel cleanliness of a head billet in the prior art is poor, the quality cannot reach the quality of a normal billet, and the head billet can only be treated in a degradation or scrapping mode due to the fact that the quality cannot reach the quality of the normal billet is solved.
In order to better understand the technical solution, the technical solution will be described in detail with reference to the drawings and the specific embodiments.
In order to solve the technical problems that in the prior art, the cleanliness of molten steel of a head billet is poor, the quality cannot reach the quality of a normal billet, the head billet can only be treated in a degradation or scrapping mode, and the material waste is caused, the method for improving the quality of the head billet of the IF steel casting billet is provided.
The factors influencing the cleanliness of the head blank are more, and the factors mainly comprise: 1) when the large ladle molten steel enters the tundish, the molten steel is exposed to air to cause secondary oxidation of the molten steel; 2) oxidation of molten steel by tundish refractory, covering agent, etc.; 3) the entrainment of the mold flux, and the like.
Specifically, as shown in fig. 1, the method for improving the quality of the IF steel casting blank head blank comprises the following steps:
and step 110, adding a covering agent when the tonnage of the molten steel of the continuous casting tundish reaches 35 tons.
In the prior art, after a large ladle of molten steel is started, the molten steel in the ladle flows into a tundish from a long nozzle, the molten steel is exposed to air, secondary oxidation of the molten steel is easily caused, the oxygen content in the molten steel is increased, and the quality is poor. According to the method, when the tonnage of the molten steel in the continuous casting tundish reaches 35 tons, the covering agent is added, namely the adding time of the covering agent of the tundish is controlled, the contact between the molten steel and air is reduced, and the oxygen content in the molten steel is reduced.
Specifically, the adding sequence is that part of the covering agent is added from two stopper holes firstly, specifically, the adding sequence is that the covering agent added from the two stopper holes is 120kg plus or minus 6kg, the covering agent is dispersed and uniformly distributed in the flowing of the molten steel, and the possibility of the covering agent of the molten steel roll is reduced; the remainder of the covering agent, specifically 390kg + -6 kg, was then added by gating off the ladle of the tundish. The total amount of the covering agent is 630 kg.
And step 120, placing casting slag and crystallizer covering slag on the crystallizer platform.
And (3) carrying out casting operation on the continuous casting tundish, when the tonnage of the tundish reaches 50 tons, lifting the continuous casting stopper rod to flow downwards, feeding molten steel into the crystallizer from the submerged nozzle, and placing casting-on slag and crystallizer covering slag on a platform plate of the crystallizer. The initial casting slag and the crystallizer casting powder are 5kg-10kg and 20kg-30kg respectively. Specifically, the method comprises the following steps:
1) and when the inflow of the molten steel reaches 1/3-1/4 positions of a side hole of the submerged nozzle, adding casting slag, ensuring the temperature of the molten steel, providing heat, and reducing the cold steel with too low temperature in the crystallizer.
2) And when the inflow of the molten steel reaches 100mm above a side hole of the submerged nozzle, 1/3 crystallizer casting slag is added, and the contact between the molten steel and air is reduced.
3) And after the car is started, adding the residual 2/3 crystallizer casting powder, and ensuring that the crystallizer casting powder is added in a full-coverage manner and uniformly scattered in the crystallizer.
And step 130, controlling the continuous casting drawing speed.
As the liquid level fluctuation in the crystallizer is obviously larger than that in the stable pulling speed in the pulling speed rising stage at the initial casting starting stage, the pulling speed is controlled to be 0.2m/min after starting, then is increased to 0.4m/min, the acceleration is less than or equal to 0.05m/min as shown in figure 22Keeping 30s +/-5 s; then the speed is increased from 0.4m/min to 0.8m/min, and the acceleration is less than or equal to 0.05m/min2And keeping 30s +/-5 s.
This application is through reasonable control tundish covering agent joining opportunity, casting tonnage is opened to the tundish carries out reasonable control, increase inclusion come-up time, the reasonable joining opportunity of casting slag and covering slag in the crystallizer, a series of measures such as optimizing to the pulling speed that rises when casting, control that can be fine is rolled up the sediment and is mingled with within 4 meters of head, improve the finished product volume and reduce the loss that cutting length overlength leads to, it is relatively poor to have solved head base molten steel cleanliness factor among the prior art, the quality can not reach the quality of normal base, lead to can only adopting degradation or condemned mode to handle the head base, cause the technical problem of material waste.
The invention has higher process application value, simple and convenient field operation and obvious effect of improving the quality of the IF steel casting blank head blank.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (8)
1. A method of improving the quality of a primary blank of an IF steel casting blank, the method comprising:
when the tonnage of molten steel in a continuous casting tundish reaches 35 tons, adding a covering agent, wherein the adding of the covering agent comprises the following steps: firstly, respectively adding part of covering agent from two stopper holes, and then pouring a gate from a steel ladle of a tundish to add the rest covering agent;
placing casting slag and crystallizer covering slag on a crystallizer platform, comprising: when the inflow amount of molten steel reaches 1/3-1/4 positions of a side hole of the submerged nozzle, adding casting slag; when the inflow of molten steel reaches 100mm above a side hole of the submerged nozzle, 1/3 crystallizer casting powder is added; when the pulling speed is after starting, adding the residual 2/3 crystallizer casting powder;
the speed of the pulling speed after starting is controlled to be 0.2m/min, then the pulling speed is increased to 0.4m/min, and the increasing acceleration is less than or equal to 0.05m/min2Keeping 30s +/-5 s; then the speed is increased from 0.4m/min to 0.8m/min, and the increasing acceleration is less than or equal to 0.05m/min2And keeping 30s +/-5 s.
2. The method of claim 1, wherein the covering agent is 630kg in total.
3. The method of claim 1 or 2, wherein the addition of the capping agent from both stopper rod orifices is 120kg ± 6kg each.
4. The method of claim 1 or 2, wherein the amount of capping agent that is degated from the ladle of the tundish is 390kg ± 6 kg.
5. The method according to claim 1, characterized in that the casting slag is in particular 5kg-10 kg.
6. The method according to claim 1, wherein the mold flux is in particular 20kg to 30 kg.
7. The method of claim 1, wherein after the pulling rate has increased from 0.4m/min to 0.8m/min for 30s ± 5s, the method further comprises:
the pulling speed is increased from 0.8m/min to 1.2m/min and is kept for 30s +/-5 s.
8. The method of claim 7, wherein after the pull rate is increased from 0.8m/min to 1.2m/min and maintained for 30s ± 5s, the method further comprises:
the pulling speed is increased from 1.2m/min to the target pulling speed of 1.4 m/min.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201810713981.2A CN108971444B (en) | 2018-06-29 | 2018-06-29 | Method for improving IF steel casting blank head blank quality |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810713981.2A CN108971444B (en) | 2018-06-29 | 2018-06-29 | Method for improving IF steel casting blank head blank quality |
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| CN108971444A CN108971444A (en) | 2018-12-11 |
| CN108971444B true CN108971444B (en) | 2020-06-12 |
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| CN111299535A (en) * | 2020-04-17 | 2020-06-19 | 攀钢集团攀枝花钢钒有限公司 | Quality control method for head covering blank in slab continuous casting |
| CN114799108A (en) * | 2022-05-17 | 2022-07-29 | 广东韶钢松山股份有限公司 | Casting starting control method for small square billet casting machine |
| CN115338377A (en) * | 2022-07-27 | 2022-11-15 | 南京钢铁股份有限公司 | Preparation method of casting blank |
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| CN103586433A (en) * | 2013-11-04 | 2014-02-19 | 南京钢铁股份有限公司 | Method for increasing flaw detection yield of continuous casting sheet head billet and tail billet |
| CN105170932A (en) * | 2015-10-16 | 2015-12-23 | 首钢总公司 | Starting speed-lifting method for improving surface quality of extremely-thick plate blank head slab |
| CN105499526A (en) * | 2014-09-25 | 2016-04-20 | 鞍钢股份有限公司 | Method for reducing total oxygen content of aluminum killed steel continuous casting head blank |
| CN106735013A (en) * | 2016-11-16 | 2017-05-31 | 南京钢铁股份有限公司 | A kind of continuous casting process for improving bloom quality of primary blank |
| CN107052289A (en) * | 2017-05-09 | 2017-08-18 | 唐山不锈钢有限责任公司 | The Adding Way of the tundish covering flux poured is opened for continuous casting |
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- 2018-06-29 CN CN201810713981.2A patent/CN108971444B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103586433A (en) * | 2013-11-04 | 2014-02-19 | 南京钢铁股份有限公司 | Method for increasing flaw detection yield of continuous casting sheet head billet and tail billet |
| CN105499526A (en) * | 2014-09-25 | 2016-04-20 | 鞍钢股份有限公司 | Method for reducing total oxygen content of aluminum killed steel continuous casting head blank |
| CN105170932A (en) * | 2015-10-16 | 2015-12-23 | 首钢总公司 | Starting speed-lifting method for improving surface quality of extremely-thick plate blank head slab |
| CN106735013A (en) * | 2016-11-16 | 2017-05-31 | 南京钢铁股份有限公司 | A kind of continuous casting process for improving bloom quality of primary blank |
| CN107052289A (en) * | 2017-05-09 | 2017-08-18 | 唐山不锈钢有限责任公司 | The Adding Way of the tundish covering flux poured is opened for continuous casting |
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