CN113695545A - Continuous casting method of small square billet meeting production requirement of large-specification wire rod cold heading steel - Google Patents
Continuous casting method of small square billet meeting production requirement of large-specification wire rod cold heading steel Download PDFInfo
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- CN113695545A CN113695545A CN202110947778.3A CN202110947778A CN113695545A CN 113695545 A CN113695545 A CN 113695545A CN 202110947778 A CN202110947778 A CN 202110947778A CN 113695545 A CN113695545 A CN 113695545A
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- 238000009749 continuous casting Methods 0.000 title claims abstract description 34
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 21
- 239000010959 steel Substances 0.000 title claims abstract description 21
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 20
- 238000000034 method Methods 0.000 title claims abstract description 14
- 238000005096 rolling process Methods 0.000 claims abstract description 35
- 238000005266 casting Methods 0.000 claims abstract description 27
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 12
- 238000003756 stirring Methods 0.000 claims abstract description 8
- 238000001816 cooling Methods 0.000 claims abstract description 5
- 239000013078 crystal Substances 0.000 abstract description 12
- 238000003825 pressing Methods 0.000 abstract description 10
- 238000010273 cold forging Methods 0.000 abstract description 4
- 230000006835 compression Effects 0.000 abstract description 4
- 238000007906 compression Methods 0.000 abstract description 4
- 238000005098 hot rolling Methods 0.000 abstract description 3
- 238000010438 heat treatment Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 3
- 238000004806 packaging method and process Methods 0.000 description 3
- 238000005204 segregation Methods 0.000 description 3
- 238000013459 approach Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005554 pickling Methods 0.000 description 2
- 238000011946 reduction process Methods 0.000 description 2
- 238000002791 soaking Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000003908 quality control method Methods 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
-
- 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
- B22D11/18—Controlling or regulating processes or operations for pouring
-
- 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
- B22D11/225—Controlling or regulating processes or operations for cooling cast stock or mould for secondary cooling
Abstract
The invention relates to a continuous casting method of a small square billet meeting the requirement of producing large-size wire rod cold forging steel, which comprises the steps of selecting a continuous casting billet with the section size of 160mm multiplied by 160mm, controlling the drawing speed to be 2.3-2.8 m/min, controlling the superheat degree to be 35-45 ℃, adopting a straight-through submerged nozzle, and controlling the secondary cooling specific water amount to be 0.8-1.4L/kg; and closing the electromagnetic stirring at the tail end, and equipping the continuous casting machine with 7 withdrawal straightening machines, wherein 4# to 7# withdrawal straightening rollers are adopted for pressing, the single-roller pressing amount is 5-12 mm, the total pressing amount is 20-40 mm, and the total deformation amount is 10-25%. According to the invention, high drawing speed, high superheat degree and high specific water content are adopted for casting, the electromagnetic stirring at the tail end is closed, the continuous casting billet is reduced by adopting a large reduction of 20-40 mm to obtain columnar crystals with a higher proportion, the central porosity and shrinkage cavity of the casting billet are improved, the density of the continuous casting billet reaches the hot rolling state control level, and the rolling of large-size wire rods is realized under the condition of adopting a small compression ratio, so that the production of replacing two hot rods by one hot rod is realized, and the purposes of reducing the production cost and improving the product quality are finally achieved.
Description
Technical Field
The invention relates to the technical field of continuous casting, in particular to a small square billet continuous casting method for producing large-specification wire rod cold heading steel.
Background
Cold heading steel is mainly used for machining and manufacturing fasteners and connectors (such as bolts, nuts, screws, rivets and the like). Cold heading properties are one of the important properties of cold heading steel. At present, cold forging steel wires with the specification of less than phi 25 are mainly rolled by small square billets domestically, and the section size of the casting billet is basically 140-180 mm in width and 140-180 mm in thickness. For a cold forging steel wire rod with larger specification such as phi 30-phi 50, because a designed rolling mill cannot directly roll a large-section casting blank, and the direct rolling of a small-section casting blank has the problem of low compression ratio, so that the center of the wire rod is loose, the hole shrinkage and the like are difficult to meet the quality control requirement, usually, only two-hot-material production process can be adopted, namely, the large-section casting blank is firstly blanked into the small-section casting blank, and then the small-section casting blank is rolled, and the method has the problems of high production cost, low production efficiency and about 400-600 yuan increase in average steel cost per ton.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: in order to overcome the defects in the prior art, the invention provides a small square billet continuous casting method for producing large-specification wire rod cold heading steel, which optimizes the continuous casting process parameters to ensure that the density of a continuous casting billet before rolling reaches or approaches the hot rolling state control level, thereby ensuring that indexes such as center porosity, segregation and the like of large-specification wire rods completely meet the quality requirements for producing large-specification wire rod cold heading steel under the production condition of a small compression ratio.
The technical scheme adopted by the invention for solving the technical problems is as follows: a small square billet continuous casting method for producing large-specification wire rod cold heading steel comprises the following steps:
(1) the section size of the continuous casting billet is 160 multiplied by 160mm2；
(2) The drawing speed of the continuous casting billet is 2.3-2.8 m/min;
(3) controlling the superheat degree of molten steel to be 35-45 ℃ before casting, and closing the electromagnetic stirring at the tail end;
(4) adopting a straight-through type submerged nozzle, wherein the secondary cooling specific water amount is 0.8-1.4L/kg;
(5) the continuous casting machine is provided with 7 withdrawal and straightening machines, the 1# to 3# withdrawal and straightening rollers do not conduct reduction, the 4# to 7# withdrawal and straightening rollers conduct reduction, pressure is applied to the thickness direction of a casting blank, the reduction of a single roller can be enabled to be 5-12 mm, the total reduction of the thickness of the casting blank is 20-40 mm, and the total deformation of the thickness of the casting blank is 10-25%.
The rolling specification of the wire rod is phi 30-phi 50.
The continuous casting billet adopts a large coil rolling process, the rolling parameters are obtained according to a conventional process, the rolling parameters do not need to be adjusted or optimized intentionally, the rolling process is that the continuous casting billet is subjected to high-pressure water descaling after passing through a heating furnace, and then is subjected to rough rolling, medium rolling, pre-finish rolling, three-roller kocks rolling, curling, packaging and warehousing in sequence.
Through the research on the reduction effect, the center of the casting blank is columnar crystal, and the reduction process is adopted to more easily press the central shrinkage cavity due to the directivity of the columnar crystal; when the center is isometric crystal, as the isometric crystal has no directionality, the pressing process is adopted, the center loosening and shrinkage cavity control effects are not obvious without columnar crystal, and a typical schematic diagram is shown in figure 1.
Therefore, in order to obtain more columnar crystals, the method abandons the traditional casting process with low superheat degree, low pulling speed and low specific water content, adopts high superheat degree, high pulling speed and high specific water content for casting, and closes the electromagnetic stirring at the tail end so as to maximally improve the proportion of the columnar crystals and reduce the proportion of equiaxed crystals. Meanwhile, the central shrinkage cavity is pressed in cooperation with a large reduction process, and the obtained continuous casting billet can meet the requirement of producing large-specification wire rod cold forging steel by adopting a hot material production process.
The invention has the beneficial effects that: according to the invention, high drawing speed, high superheat degree and high specific water content are adopted for casting, the electromagnetic stirring at the tail end is closed, and the large reduction of 20-40 mm is adopted for reducing the continuous casting billet to obtain columnar crystals with higher proportion, so that the central porosity and shrinkage cavity of the casting billet are improved, the density of the continuous casting billet reaches or approaches to the hot rolling state control level, and the rolling of large-size wire rods is realized under the condition of small compression ratio, so that the production of replacing two hot rods by one hot rod is realized, and the purposes of reducing the production cost and improving the product quality are finally achieved.
Drawings
The invention is further illustrated with reference to the following figures and examples.
FIG. 1 is a schematic view of the light pressure effect of columnar crystal and equiaxed crystal.
FIG. 2 is a photograph of a longitudinal cut of a cast slab of example 1 after pickling of a low-magnification sample.
FIG. 3 is a photograph of a longitudinal cut of a cast slab obtained in example 2 after pickling of a low-magnification sample.
Detailed Description
The present invention will now be described in further detail with reference to examples.
Example 1:
the embodiment provides a small square billet continuous casting method for producing large-specification wire rod cold heading steel.
And (3) continuous casting process: adopting a 160X 160 section continuous casting machine for production, controlling the drawing speed to be 2.5m/min, controlling the superheat degree to be 42 ℃, adopting a straight-through submerged nozzle, controlling the secondary cooling specific water amount to be 1.2L/kg, and closing the electromagnetic stirring at the tail end; and 4# to 7# withdrawal and straightening rollers are adopted for pressing, the pressing amount is 6 mm, 8 mm and 5mm respectively, and the total pressing amount is 25 mm.
And a steel rolling process, namely, a large coil rolling process is adopted, rolling parameters are obtained according to a conventional process, the rolling parameters do not need to be adjusted or optimized intentionally, the rolling process is that the temperature of a casting blank in a heating section is 1020 ℃, the temperature of a soaking section is 1075 ℃, the rolling temperature is 1030 ℃, the total heating time is 125min, the casting blank is descaled by high pressure water after passing through a heating furnace, and then the casting blank is subjected to rough rolling, medium rolling, pre-finish rolling, three-roll kocks rolling mill, curling, packaging and warehousing sequentially.
And (3) detection results: the picture of the acid-washed longitudinal section of the continuous casting blank is shown in figure 2, the central shrinkage cavity is completely pressed, the central segregation and the porosity are 0.5 grade, and the central shrinkage cavity is 0 grade; the specification of the hot-rolled wire rod is phi 38, the center of the wire rod is segregated and loosened by 0.5 grade, and the quality requirement is completely met.
Example 2:
the embodiment provides a small square billet continuous casting method for producing large-specification wire rod cold heading steel.
And (3) continuous casting process: adopting a 160X 160 section continuous casting machine for production, controlling the drawing speed to be 2.6m/min, controlling the superheat degree to be 39 ℃, adopting a straight-through submerged nozzle, controlling the secondary cooling specific water amount to be 1.2L/kg, and closing the electromagnetic stirring at the tail end; and 4# to 7# withdrawal and straightening rollers are adopted for pressing, the pressing amount is 6 mm, 7 mm, 8 mm and 9mm respectively, and the total pressing amount is 30 mm.
The steel rolling process adopts a large coil rolling process, rolling parameters are obtained according to a conventional process, the rolling parameters do not need to be adjusted or optimized intentionally, the rolling process is that the temperature of a casting blank in a heating section is 1043 ℃, the temperature of a soaking section is 1085 ℃, the rolling temperature is 1042 ℃, the total heating time is 138min, the casting blank is descaled by high pressure water after passing through a heating furnace, and then the casting blank is subjected to rough rolling, medium rolling, pre-finish rolling, three-roll kocks rolling mill, curling, packaging and warehousing in sequence.
And (3) detection results: the picture of the acid-washed longitudinal section of the continuous casting blank is shown in figure 3, the central shrinkage cavity is completely pressed, the central segregation and the porosity are 0.5 grade, and the central shrinkage cavity is 0 grade; the specification of the hot-rolled wire rod is phi 42, the center of the wire rod is segregated and loosened by 0.5 grade, and the quality requirement is completely met.
In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.
Claims (2)
1. A continuous casting method of small square billets for producing large-specification wire cold heading steel is characterized by comprising the following steps: the method comprises the following steps:
(1) the section size of the continuous casting billet is 160 multiplied by 160mm2；
(2) The drawing speed of the continuous casting billet is 2.3-2.8 m/min;
(3) controlling the superheat degree of molten steel to be 35-45 ℃ before casting, and closing the electromagnetic stirring at the tail end;
(4) adopting a straight-through type submerged nozzle, wherein the secondary cooling specific water amount is 0.8-1.4L/kg;
(5) the continuous casting machine is provided with 7 withdrawal and straightening machines, the 1# to 3# withdrawal and straightening rollers do not conduct reduction, the 4# to 7# withdrawal and straightening rollers conduct reduction, pressure is applied to the thickness direction of a casting blank, the reduction of a single roller can be enabled to be 5-12 mm, the total reduction of the thickness of the casting blank is 20-40 mm, and the total deformation of the thickness of the casting blank is 10-25%.
2. The billet continuous casting method for producing the large-specification wire rod cold heading steel, which is required to be described in claim 1, is characterized in that: the rolling specification of the wire rod is phi 30-phi 50.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110947778.3A CN113695545B (en) | 2021-08-18 | 2021-08-18 | Continuous casting method of small square billet meeting production requirement of large-specification wire rod cold heading steel |
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| CN202110947778.3A CN113695545B (en) | 2021-08-18 | 2021-08-18 | Continuous casting method of small square billet meeting production requirement of large-specification wire rod cold heading steel |
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| CN113695545A true CN113695545A (en) | 2021-11-26 |
| CN113695545B CN113695545B (en) | 2023-03-24 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114657444A (en) * | 2022-03-25 | 2022-06-24 | 中天钢铁集团有限公司 | Method for producing steel QD08 for claw pole of motor by using small square billet with 160mm multiplied by 160mm section |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101147966A (en) * | 2007-10-29 | 2008-03-26 | 江苏沙钢集团淮钢特钢有限公司 | Continuous casting columnar crystallizer small square blank and its columnar crystal control method |
| CN103506586A (en) * | 2012-06-20 | 2014-01-15 | 鞍钢股份有限公司 | Continuous casting method for improving central shrinkage cavity of small high-carbon steel square billet |
| CN104874758A (en) * | 2015-05-11 | 2015-09-02 | 中冶连铸技术工程有限责任公司 | Control method and device under continuous casting weight |
| US20170216908A1 (en) * | 2014-03-27 | 2017-08-03 | Primetals Technologies Austria GmbH | Semi-continuous casting of a steel strip |
| CN109622904A (en) * | 2019-02-01 | 2019-04-16 | 东北大学 | A kind of device and method for realizing continuous cast round billets process of setting core soft reduction process |
| CN109732049A (en) * | 2019-02-21 | 2019-05-10 | 东北大学 | A kind of vertical throwing conticaster of small billet and soft reduction process device |
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2021
- 2021-08-18 CN CN202110947778.3A patent/CN113695545B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101147966A (en) * | 2007-10-29 | 2008-03-26 | 江苏沙钢集团淮钢特钢有限公司 | Continuous casting columnar crystallizer small square blank and its columnar crystal control method |
| CN103506586A (en) * | 2012-06-20 | 2014-01-15 | 鞍钢股份有限公司 | Continuous casting method for improving central shrinkage cavity of small high-carbon steel square billet |
| US20170216908A1 (en) * | 2014-03-27 | 2017-08-03 | Primetals Technologies Austria GmbH | Semi-continuous casting of a steel strip |
| CN104874758A (en) * | 2015-05-11 | 2015-09-02 | 中冶连铸技术工程有限责任公司 | Control method and device under continuous casting weight |
| CN109622904A (en) * | 2019-02-01 | 2019-04-16 | 东北大学 | A kind of device and method for realizing continuous cast round billets process of setting core soft reduction process |
| CN109732049A (en) * | 2019-02-21 | 2019-05-10 | 东北大学 | A kind of vertical throwing conticaster of small billet and soft reduction process device |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114657444A (en) * | 2022-03-25 | 2022-06-24 | 中天钢铁集团有限公司 | Method for producing steel QD08 for claw pole of motor by using small square billet with 160mm multiplied by 160mm section |
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| CN113695545B (en) | 2023-03-24 |
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