CN114054707A - Method for reducing center segregation of pipeline steel continuous casting billet - Google Patents
Method for reducing center segregation of pipeline steel continuous casting billet Download PDFInfo
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- CN114054707A CN114054707A CN202111180127.2A CN202111180127A CN114054707A CN 114054707 A CN114054707 A CN 114054707A CN 202111180127 A CN202111180127 A CN 202111180127A CN 114054707 A CN114054707 A CN 114054707A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 35
- 239000010959 steel Substances 0.000 title claims abstract description 35
- 238000005204 segregation Methods 0.000 title claims abstract description 18
- 238000009749 continuous casting Methods 0.000 title claims abstract description 12
- 238000000034 method Methods 0.000 title claims abstract description 11
- 230000009467 reduction Effects 0.000 claims abstract description 31
- 238000005266 casting Methods 0.000 claims abstract description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 7
- 239000000498 cooling water Substances 0.000 claims abstract description 4
- 239000007788 liquid Substances 0.000 claims abstract description 3
- 238000003756 stirring Methods 0.000 claims abstract description 3
- 238000005507 spraying Methods 0.000 claims description 8
- 238000003825 pressing Methods 0.000 claims description 4
- 230000007613 environmental effect Effects 0.000 claims description 2
- 230000008569 process Effects 0.000 abstract description 3
- 230000000694 effects Effects 0.000 description 5
- 238000005096 rolling process Methods 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 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
- B22D11/16—Controlling or regulating processes or operations
- B22D11/20—Controlling or regulating processes or operations for removing cast stock
-
- 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
- B22D11/114—Treating the molten metal by using agitating or vibrating means
- B22D11/115—Treating the molten metal by using agitating or vibrating means by using magnetic fields
-
- 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
- B22D11/12—Accessories for subsequent treating or working cast stock in situ
- B22D11/1206—Accessories for subsequent treating or working cast stock in situ for plastic shaping of strands
-
- 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
-
- 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
- B22D11/22—Controlling or regulating processes or operations for cooling cast stock or mould
Abstract
The invention discloses a method for reducing center segregation of a pipeline steel continuous casting billet, which comprises the following steps: the superheat degree of the molten steel is stabilized at 15-28 ℃; selecting a pulling speed according to the section of the casting blank, wherein the pulling speed is controlled to be 0.9-1.1 m/min; the radian and the opening degree of the sector section are accurately controlled; the temperature of secondary cooling water is kept at 22-28 ℃, and the specific water amount is controlled at 0.6-0.7L/kg steel; 2 rollers for electromagnetic stirring are respectively arranged at the 3-section outlet and the 4-section inlet, the current intensity is 350A, and the frequency is 5 Hz; the dynamic control of pressure is used in soft reduction to solve the problem of inaccurate finding of the tail end position of the liquid cavity of the casting blank. According to the invention, the casting parameters of the casting machine process are optimized, the equipment precision of the sector section is ensured, the soft reduction position and the reduction are dynamically adjusted, the control level of the center segregation of the pipeline steel is obviously improved, the internal quality of the casting blank is improved, and the competitiveness of the product is enhanced.
Description
Technical Field
The invention relates to the technical field of continuous casting in the metallurgical industry, in particular to a method for reducing center segregation of a pipeline steel continuous casting billet.
Background
Because the geographical environment of the petroleum pipeline is very severe, higher requirements are put on the strength, toughness, weldability and corrosion resistance of pipeline steel, the requirement on the center segregation of a casting blank is quite severe, if the center segregation is unqualified, the components of each element at the final solidification position of the continuous casting blank are higher, so that non-metallic inclusions such as MnS are formed, a strip-shaped structure is formed, the anisotropy of the continuous casting blank structure is caused, and the non-metallic inclusions extend and crack after the rolling deformation, so that the performance of a rolled steel plate is not good. The low-power C-type segregation rate of the pipeline steel of the steel-clad wide plate casting machine is only about 60%, and a technical worker forms a whole set of continuous casting process suitable for controlling the internal quality of the pipeline steel produced by the plate blank through autonomous attack and closing, so that the low-power C-type segregation rate of the pipeline steel casting blank reaches over 95%.
The chinese patent application No. 201510998706.6 discloses a control method for typical intermediate cracks and center segregation in continuous casting of a pipeline steel slab, which can effectively reduce the incidence of the intermediate cracks near a triangular area and improve the control level of the center segregation. However, the secondary cooling water used in the invention has higher specific water content, belongs to strong cooling, is easy to generate surface cracks of a casting blank, can only be adjusted along with the pulling speed at a light reduction position, cannot realize dynamic adjustment according to the pressure at the tail end of reduction, and has larger central segregation fluctuation.
Disclosure of Invention
The invention aims to provide a method for reducing the center segregation of a pipeline steel continuous casting billet, which ensures the equipment precision of a sector section by optimizing the casting parameters of a casting machine process, dynamically adjusts the soft reduction position and the reduction, obviously improves the control level of the center segregation of the pipeline steel, improves the internal quality of the casting billet and enhances the competitiveness of products.
In order to solve the technical problems, the invention adopts the following technical scheme:
the invention discloses a method for reducing center segregation of a pipeline steel continuous casting billet, which comprises the following steps:
the superheat degree of the molten steel is stabilized at 15-28 ℃;
selecting a pulling speed according to the section of the casting blank, wherein the pulling speed is controlled to be 0.9-1.1 m/min;
accurate control fan-shaped section radian and opening degree include: the radian error of the roller in the sector section and between the sections is less than or equal to 0.3 mm; calibrating and adjusting the opening degree of the sector section to ensure that the error is not more than 1 mm;
checking the water spraying condition of the fan-shaped section spraying strips, and immediately replacing the fan-shaped section spraying strips if the fan-shaped section spraying strips are blocked;
the temperature of secondary cooling water is kept at 22-28 ℃, and the specific water amount is controlled at 0.6-0.7L/kg steel;
2 rollers for electromagnetic stirring are respectively arranged at the 3-section outlet and the 4-section inlet, the current intensity is 350A, and the frequency is 5 Hz;
the soft reduction uses pressure dynamic control to solve the problem of inaccurate finding of the tail end position of a liquid cavity of a casting blank, the pressure dynamic control soft reduction is a preset reasonable pressure value range of a fan-shaped section, a pressure value during actual steel casting is compared with the preset pressure value, and if the pressure value exceeds the required range, a PLC system can automatically adjust the reduction value of the fan-shaped section, so that the influence of factors such as accuracy error of the fan-shaped section, environmental temperature and the like on the reduction tail end is overcome;
wherein:
the pipeline steel is pressed down by adopting three sections of 6, 7 and 8 at the pulling speed of 0.9m/min, the set pressing amount of each section is 2.5mm, and the specific pressure set value and the opening degree set value are shown in the table:
B. the pipeline steel is pressed down by adopting three sections of 7, 8 and 9 at the pulling speed of 1.0m/min, the set pressing amount of each section is 2.5mm, and the specific pressure set value and the opening degree set value are shown in the table:
C. the pipeline steel is pressed down by three sections of 8, 9 and 10 at the pulling speed of 1.1m/min, the set reduction of each section is 2.5mm, and the specific pressure set value and the opening degree set value are shown in the table:
the actual pressure values of the inlet and the outlet of the fan-shaped section are required to be within a set range, if the actual pressure values are higher than the maximum value, the PLC system can automatically adjust the opening degree of the corresponding position of the fan-shaped section, and the opening degree is increased by 0.5mm on the basis of a set value; otherwise, the actual pressure value is smaller than the minimum value, and the PLC system can automatically reduce the opening degree of the corresponding position of the fan-shaped section by 0.5mm on the basis of the set value.
Compared with the prior art, the invention has the beneficial technical effects that:
when the pipeline steel is cast, the technical measures are comprehensively adopted, particularly the dynamic control of the pressure is used under the light pressure, so that the center segregation of the pipeline steel casting blank is obviously reduced, the internal quality is obviously improved, the low-power C-type segregation rate reaches more than 95 percent, and the competitiveness of the product is improved.
Drawings
FIG. 1 shows the macroscopic effects of the cast slab of example 1 of the present invention.
FIG. 2 shows the macroscopic effect of the cast slab in example 2 of the present invention.
FIG. 3 shows the macroscopic effect of the cast slab in example 3 of the present invention.
FIG. 4 shows the macroscopic effects of the cast slab in example 4 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the present invention will be described in detail and fully below with reference to the embodiments.
Measure fan-shaped section radian before the pipeline steel casting, guarantee that the radian is no longer than 0.3mm between the roller, calibration fan-shaped section opening degree, the error is no longer than 1mm, and the inspection sprays the strip water spray condition, and the accurate blocking phenomenon that has, if block up, changes immediately. Table 1 shows the casting parameters for the casting of the steel for the line pipes in the examples.
Table 1 examples pipeline steel casting parameters
The actual pressure values and the opening degrees of the soft reduction stage in example 1 are shown in table 2:
table 2 example 1 actual pressure value and opening degree of the lower pressure section
It can be seen that, in example 1, the actual pressure values are all within the range of the design pressure values, the set reduction value is executed for the reduction of the soft reduction section, and the opening degree is unchanged, i.e. the soft reduction of each section of 8, 9 and 10 is 2.5mm respectively.
The actual pressure value and the opening degree of the soft reduction stage in example 2 are shown in table 3:
TABLE 3 practical pressure value and opening degree of the pressure stage of example 2
It can be seen that, in embodiment 2, the actual pressure value 118bar of the 8-stage inlet, which is affected by the factors such as the equipment precision and the ambient temperature, is smaller than the set minimum pressure value, the PLC system automatically increases the pressure of the 8-stage inlet by 0.5mm, that is, the opening degree is changed from 263.7mm to 263.2 mm; and the actual pressure values of the 8-section outlet, the 9-section outlet and the 10-section outlet are all within the set pressure value range, and the rolling reduction is kept unchanged. The actual soft reduction of the final 3 segments is respectively: 2.0mm,2.5 mm.
The actual pressure value and the opening degree of the soft reduction stage in example 3 are shown in table 4:
TABLE 4 practical pressure value and opening degree of the pressure zone in example 3
It can be seen that in example 3, the actual pressure values of the outlets in sections 7, 8 and 9 are all within the range of the set pressure value, the light reduction is unchanged, while the inlet in section 9 is affected by the equipment precision, the ambient temperature and other factors, the actual pressure value 177bar exceeds the upper limit of the set pressure value, and the PLC system will automatically change the opening degree of the inlet in section 9 from 259.2mm to 259.7mm, that is, the final reduction of 3 sections is 2.5mm, 2.5mm and 3.0 mm.
The actual pressure values and the opening degrees of the soft reduction stage in example 4 are shown in table 5:
TABLE 5 practical pressure value and opening degree of the lower pressure section in example 4
It can be seen that, in embodiment 4, the actual pressure value 126bar of the inlet at the 6-stage is smaller than the set minimum value, and the PLC system automatically increases the pressure at the inlet at the 6-stage by 0.5mm, that is, the opening degree is changed from 265.0mm to 264.5 mm; the actual pressure value 198bar of the 8-section outlet is larger than the set maximum value, the PLC system automatically lifts the 8-section outlet by 0.5mm, namely the opening degree is changed from 257.3mm to 257.8 mm; the actual pressure values of the 6-section outlet, the 7-section inlet and the 8-section inlet are all in the set pressure value range, the reduction value is kept unchanged, and finally the soft reduction of 3 sections is 2.0mm,2.5mm and 2.0 mm.
After the pipeline steel cast in the above examples is comprehensively applied by the above technical measures, the casting blank low power condition is as shown in table 6:
TABLE 6 example low power results
| Examples | Low power result |
| Example 1 | C1.0 |
| Example 2 | C0.5 |
| Example 3 | C0.5 |
| Example 4 | C1.0 |
The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.
Claims (1)
1. A method for reducing center segregation of a pipeline steel continuous casting billet is characterized by comprising the following steps:
the superheat degree of the molten steel is stabilized at 15-28 ℃;
selecting a pulling speed according to the section of the casting blank, wherein the pulling speed is controlled to be 0.9-1.1 m/min;
accurate control fan-shaped section radian and opening degree include: the radian error of the roller in the sector section and between the sections is less than or equal to 0.3 mm; calibrating and adjusting the opening degree of the sector section to ensure that the error is not more than 1 mm;
checking the water spraying condition of the fan-shaped section spraying strips, and immediately replacing the fan-shaped section spraying strips if the fan-shaped section spraying strips are blocked;
the temperature of secondary cooling water is kept at 22-28 ℃, and the specific water amount is controlled at 0.6-0.7L/kg steel;
2 rollers for electromagnetic stirring are respectively arranged at the 3-section outlet and the 4-section inlet, the current intensity is 350A, and the frequency is 5 Hz;
the soft reduction uses pressure dynamic control to solve the problem of inaccurate finding of the tail end position of a liquid cavity of a casting blank, the pressure dynamic control soft reduction is a preset reasonable pressure value range of a fan-shaped section, a pressure value during actual steel casting is compared with the preset pressure value, and if the pressure value exceeds the required range, a PLC system can automatically adjust the reduction value of the fan-shaped section, so that the influence of factors such as accuracy error of the fan-shaped section, environmental temperature and the like on the reduction tail end is overcome;
wherein:
the pipeline steel is pressed down by adopting three sections of 6, 7 and 8 at the pulling speed of 0.9m/min, the set pressing amount of each section is 2.5mm, and the specific pressure set value and the opening degree set value are shown in the table:
B. the pipeline steel is pressed down by adopting three sections of 7, 8 and 9 at the pulling speed of 1.0m/min, the set pressing amount of each section is 2.5mm, and the specific pressure set value and the opening degree set value are shown in the table:
C. the pipeline steel is pressed down by three sections of 8, 9 and 10 at the pulling speed of 1.1m/min, the set reduction of each section is 2.5mm, and the specific pressure set value and the opening degree set value are shown in the table:
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| CN202111180127.2A CN114054707A (en) | 2021-10-11 | 2021-10-11 | Method for reducing center segregation of pipeline steel continuous casting billet |
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| CN202111180127.2A CN114054707A (en) | 2021-10-11 | 2021-10-11 | Method for reducing center segregation of pipeline steel continuous casting billet |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115094297A (en) * | 2022-05-06 | 2022-09-23 | 包头钢铁（集团）有限责任公司 | Production method of thick Q420Q steel |
| CN115365464A (en) * | 2022-09-09 | 2022-11-22 | 包头钢铁（集团）有限责任公司 | Method for improving center segregation of wide plate casting blank |
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| JP2013010112A (en) * | 2011-06-29 | 2013-01-17 | Jfe Steel Corp | Method for continuously casting cast slab for line pipe steel plate |
| CN105562642A (en) * | 2015-12-26 | 2016-05-11 | 首钢总公司 | Control method for typical middle cracks and center segregation during pipeline steel slab continuous casting |
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-
2021
- 2021-10-11 CN CN202111180127.2A patent/CN114054707A/en active Pending
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| JP2013010112A (en) * | 2011-06-29 | 2013-01-17 | Jfe Steel Corp | Method for continuously casting cast slab for line pipe steel plate |
| CN105562642A (en) * | 2015-12-26 | 2016-05-11 | 首钢总公司 | Control method for typical middle cracks and center segregation during pipeline steel slab continuous casting |
| CN107442756A (en) * | 2017-07-21 | 2017-12-08 | 首钢集团有限公司 | The method for improving slab slighter compress efficiency |
| CN109500370A (en) * | 2018-11-12 | 2019-03-22 | 包头钢铁（集团）有限责任公司 | A kind of method of novel Wide and Thick Slab casting machine pressure control dynamic soft-reduction |
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Non-Patent Citations (1)
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| 王皓等: ""宽厚板铸机压力控制轻压下功能研究与应用"", 《炼钢》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115094297A (en) * | 2022-05-06 | 2022-09-23 | 包头钢铁（集团）有限责任公司 | Production method of thick Q420Q steel |
| CN115365464A (en) * | 2022-09-09 | 2022-11-22 | 包头钢铁（集团）有限责任公司 | Method for improving center segregation of wide plate casting blank |
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Application publication date: 20220218 |