CN115652181B - Manufacturing method of steel large round billet for high-carbon low-alloy hot roller - Google Patents
Manufacturing method of steel large round billet for high-carbon low-alloy hot roller Download PDFInfo
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 60
- 239000010959 steel Substances 0.000 title claims abstract description 60
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 34
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 25
- 229910045601 alloy Inorganic materials 0.000 title claims abstract description 24
- 239000000956 alloy Substances 0.000 title claims abstract description 24
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims abstract description 64
- 238000009749 continuous casting Methods 0.000 claims abstract description 48
- 238000000034 method Methods 0.000 claims abstract description 46
- 238000010583 slow cooling Methods 0.000 claims abstract description 34
- 229910052786 argon Inorganic materials 0.000 claims abstract description 32
- 238000005266 casting Methods 0.000 claims abstract description 26
- 238000007670 refining Methods 0.000 claims abstract description 19
- 238000007664 blowing Methods 0.000 claims abstract description 17
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 15
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 11
- 238000003723 Smelting Methods 0.000 claims abstract description 10
- 238000009849 vacuum degassing Methods 0.000 claims abstract description 7
- 239000002893 slag Substances 0.000 claims description 28
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 27
- 238000010438 heat treatment Methods 0.000 claims description 24
- 229910052742 iron Inorganic materials 0.000 claims description 12
- 238000004321 preservation Methods 0.000 claims description 12
- 238000010079 rubber tapping Methods 0.000 claims description 12
- 238000003756 stirring Methods 0.000 claims description 10
- 229910052698 phosphorus Inorganic materials 0.000 claims description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- 229910000677 High-carbon steel Inorganic materials 0.000 claims description 6
- 238000005275 alloying Methods 0.000 claims description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 6
- 229910052782 aluminium Inorganic materials 0.000 claims description 6
- 238000001816 cooling Methods 0.000 claims description 6
- 230000006698 induction Effects 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 6
- 238000005086 pumping Methods 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 239000002994 raw material Substances 0.000 claims description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 3
- 239000001257 hydrogen Substances 0.000 claims description 3
- 229910052739 hydrogen Inorganic materials 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 239000001301 oxygen Substances 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 238000005204 segregation Methods 0.000 abstract description 3
- 238000005272 metallurgy Methods 0.000 abstract description 2
- 230000001276 controlling effect Effects 0.000 description 9
- 239000011651 chromium Substances 0.000 description 7
- 239000007789 gas Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 238000006477 desulfuration reaction Methods 0.000 description 4
- 230000023556 desulfurization Effects 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 150000001247 metal acetylides Chemical class 0.000 description 4
- 238000005070 sampling Methods 0.000 description 4
- 230000002708 enhancing effect Effects 0.000 description 3
- 230000008520 organization Effects 0.000 description 3
- 238000009489 vacuum treatment Methods 0.000 description 3
- 229910001339 C alloy Inorganic materials 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 210000001787 dendrite Anatomy 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
Classifications
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- 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
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Abstract
The invention belongs to the technical field of metallurgy, and relates to a method for manufacturing a steel round billet for a high-carbon low-alloy hot roller, which comprises the following steps: 1) Smelting; 2) Refining; 3) Vacuum degassing: controlling the steel feeding temperature after argon: continuous casting first furnace: the liquidus is added with 80-105 ℃, and the liquidus is added with 55-80 ℃ for the second furnace; argon blowing flow rate: 10-30NL/min; vacuum degree is less than or equal to 67pa, argon blowing flow rate: 50-100NL/min; after the air is broken, adding a covering agent; 4) In the continuous casting process: the control temperature of the heat is 1491-1511 ℃; casting, namely, feeding the casting into a withdrawal and straightening machine to measure the temperature, wherein the temperature is more than or equal to 915 ℃, and the working pressure of the withdrawal and straightening machine is less than or equal to 50Mpa; 5) In the slow cooling process: the pit entering temperature is more than or equal to 550 ℃, and the pit exiting temperature is less than or equal to 200 ℃. According to the invention, through a reasonable component system design, the continuous casting process improves carbon segregation, and improves the temperature entering the withdrawal and straightening machine and the strength of the withdrawal and straightening machine.
Description
Technical Field
The invention belongs to the technical field of metallurgy, and relates to a method for manufacturing a large round steel blank for a high-carbon low-alloy hot roller.
Background
The high-carbon alloy steel 60CrMnMo steel ingot is generally forged into a hot roller, but the yield of the steel ingot is about 80 percent and is far lower than that of a continuous casting billet of 92-95 percent because the steel ingot is low, so the processing cost is high. Because the carbon content in the steel is higher, and certain chromium and molybdenum elements are added, the deformation resistance of the steel is larger, the hardness is high easily caused by the traditional continuous casting production, the damage of a withdrawal and straightening machine is caused by the large deformation resistance, and meanwhile, the problem of warping of a continuous casting blank cannot be solved, and the production condition cannot be met.
Due to the high carbon content and alloy content of the steel types, large-size liquid separation carbide is often generated due to serious dendrite segregation in the solidification process, and the size of the liquid separation carbide can reach hundreds of micrometers. In order to eliminate the influence of these coarse carbides on the bearing service life, it is necessary to arrange the carbides uniformly and orderly by deforming. However, due to the large amount of large carbides, damage and even cracking between the carbides and the matrix are often caused in the conventional deformation process, and the hole type micro defects become fatigue sources in the part service process, so that the service life is greatly shortened, and the safety is greatly improved.
Disclosure of Invention
The invention aims atIn order to overcome the problems, a method for manufacturing a large round steel blank for a high-carbon low-alloy hot roller is provided, and the specification is as followsA method for manufacturing a high-carbon alloy steel large round billet for a hot roller. The invention improves carbon segregation, increases the temperature entering a tension leveler and the strength of the tension leveler by designing a reasonable component system and meets the production requirement>Specification process.
In order to achieve the above purpose, the invention provides a method for manufacturing a steel round billet for a high-carbon low-alloy hot roller, which comprises the following steps:
1) In the electric furnace smelting process: the proportion of molten iron is more than 60 percent; endpoint C is more than or equal to 0.15%, P is less than or equal to 0.007%;
2) Refining in a refining furnace: refining in-place components, and controlling the argon flow to be 10-30NL/min before tapping in the process of electrifying and heating to 40-80 NL/min;
3) Vacuum degassing in a VD furnace:
controlling the steel feeding temperature after argon: continuous casting first furnace: the liquidus is added with 80-105 ℃, and the liquidus is added with 55-80 ℃ for the second furnace;
argon blowing flow rate: 10-30NL/min; vacuum degree is less than or equal to 67pa, argon blowing flow rate: 50-100NL/min; after the air is broken, adding a covering agent;
4) In the continuous casting process: the control temperature of the heat is 1491-1511 ℃; casting, namely, feeding the casting into a withdrawal and straightening machine to measure the temperature, wherein the temperature is more than or equal to 915 ℃, and the working pressure of the withdrawal and straightening machine is less than or equal to 50Mpa;
5) In the slow cooling process: the pit entering temperature is more than or equal to 550 ℃, and the pit exiting temperature is less than or equal to 200 ℃.
Preferably, in the step 1), the added raw materials are hot molten iron and high-quality scrap steel, and the tapping temperature is more than or equal to 1600 ℃; and (3) alloying the steel ladle, adding alloy according to the lower limit of the components, and adding 1100-1650kg of slag forming materials. The content of S, P in the high-quality scrap steel is less than or equal to 0.025; the content of other impurity elements is low, and Sn+Pb+Sb+Bi+As is less than or equal to 0.06 percent. Scrap steel with carbon content less than or equal to 0.40 percent.
Preferably, the refined component in step 2) has C content of more than or equal to target value (0.60 percent) to 0.04 percent, mn content of more than or equal to target value (0.90 percent) to 0.06 percent and Cr content of more than or equal to target value (1.05 percent) to 0.06 percent;
preferably, in the step 2), the slag alkalinity is controlled to be more than 3.0, before one sample is taken, an aluminum wire is fed, the sample is taken under white slag for full component analysis, and the component content of C, si, mn, cr, mo, al is adjusted according to the component analysis result.
Preferably, the step 3) is performed with slag skimming before VD, wherein the slag skimming amount is about 1/5; the vacuum holding time is more than or equal to 22 minutes, and the soft blowing time is more than or equal to 15 minutes; the vacuum degree in the preliminary pumping period is more than 67 pa; 70-100kg of covering agent is added after the air break.
Preferably, in the step 4), special covering slag for high-carbon steel is adopted, and a tundish double-layer covering agent is used for protecting molten steel; using an induction heating tundish; the continuous casting machine is a 5-machine 5-strand continuous casting machine with an arc radius of 16.5 meters.
Preferably, in the casting process in the step 4), the crystallizer is stirred electromagnetically, the stirring parameter is 200-300A, the frequency is 0.9-1.1HZ, and the specific water quantity of the secondary cooling zone is 0.98-1.02L/Kg; and the maximum deformation resistance of the casting blank is less than or equal to 40Mpa in the straightening process after the casting blank enters a withdrawal and straightening machine.
Preferably, the continuous casting billet specification in the step 4)Large round billet, pulling speed control target: 0.17+/-0.02 m/min, the extreme value of the carbon deviation of the cross section of the large round billet is less than or equal to 0.03%, the maximum value is less than or equal to 0.62%, and the minimum value is less than or equal to 0.59%.
Preferably, retaining walls are arranged around the slow cooling pit in the step 5), a heat preservation cover is covered above the retaining walls to form a closed space, the heating temperature of the temperature-controlled slow cooling pit is 740-780 ℃, the heat preservation time is more than or equal to 10 hours, then the heating is stopped, the slow cooling is carried out along with the slow cooling for more than or equal to 48 hours.
Preferably, the steel of the large round steel billet for the high-carbon low-alloy hot roll has low gas content and pure steel, wherein the oxygen content is less than or equal to 15ppm; the hydrogen content is less than or equal to 1.5ppm; nitrogen is less than or equal to 90ppm. The low-power structure is excellent, wherein the central porosity is less than or equal to 2.0 level, the shrinkage cavity is less than or equal to 1.5 level, the central crack is less than or equal to 2.0 level, and the middle crack is less than 1.0 level.
Compared with the prior art, the invention has the advantages that:
the invention realizes the breakthrough from the production of steel ingot to the continuous casting production by optimizing and improving the technological parameters, overcomes the defects of high hardness, large deformation resistance and difficult continuous casting withdrawal and straightening of the steel for the high-carbon low-alloy hot roller, and has the advantages of high purity of the steel, excellent low-power tissue, simple production process, high production efficiency and high yield.
Drawings
FIG. 1 shows a microstructure of a steel continuous casting round billet for hot rolls according to example 1 of the present invention.
Detailed Description
The invention will be further illustrated with reference to specific examples.
The invention provides a method for manufacturing a steel large round billet for a high-carbon low-alloy hot roller, which comprises the following steps:
(1) In the electric furnace smelting process: hot charging molten iron and high-quality scrap steel, wherein the proportion of the molten iron is more than 60 percent; endpoint C is more than or equal to 0.15%, P is less than or equal to 0.007%; the tapping temperature is more than or equal to 1600 ℃. And (3) alloying the steel ladle, adding alloy according to the lower limit of the components, and adding 1100-1650kg of slag forming materials.
(2) Refining in a refining furnace: refining in-place components, wherein the content of C is more than or equal to a target value (0.60 percent) -0.04 percent, the content of Mn is more than or equal to a target value (0.90 percent) -0.06 percent, and the content of Cr is more than or equal to a target value (1.05) -0.06 percent. The alkalinity of slag is controlled to be more than 3.0, and the desulfurization operation is enhanced. Before taking one sample, feeding an aluminum wire, and sampling under white slag for full component analysis. According to the analysis result of the components, the content of C, si, mn, cr, mo, al components is adjusted. Argon flow is controlled to be 40-80NL/min in the electrifying and heating process, and argon flow is controlled to be 10-30NL/min before tapping.
(3) Vacuum degassing in a VD furnace: and skimming before VD, wherein the skimming amount is about 1/5. The vacuum holding time is more than or equal to 22 minutes. The soft blowing time is more than or equal to 15 minutes. Controlling the steel feeding temperature after argon: continuous casting first furnace: the liquidus is added with 80-105 ℃, and the liquidus is added with 55-80 ℃ for the second furnace. The vacuum degree in the pre-pumping period is above 67pa, and the argon blowing flow rate is as follows: 10-30NL/min; vacuum degree is less than or equal to 67pa, argon blowing flow rate: 50-100NL/min. 70-100kg of covering agent is added after the air break.
(4) In the continuous casting process: adopting special covering slag for high-carbon steel, and protecting molten steel by a double-layer covering agent of a tundish to avoid sucking air; an induction heating type tundish is used, and the temperature of all the furnace passes is controlled to be 1491-1511 ℃. The continuous casting machine is a 5-machine 5-strand continuous casting machine with an arc radius of 16.5 meters, and in the casting process, the crystallizer is subjected to electromagnetic stirring, the stirring parameter is 300A, the frequency is 1.0HZ, and the specific water quantity of the secondary cooling zone is 0.98-1.02L/Kg. The temperature of the casting blank is measured by a withdrawal and straightening machine, the temperature is more than or equal to 915 ℃, the working pressure of the withdrawal and straightening machine is less than or equal to 50Mpa, the problem of warping is solved in the straightening process after the casting blank enters the withdrawal and straightening machine, the maximum deformation resistance of the casting blank is less than or equal to 40Mpa, and the withdrawal and straightening machine meets the requirements. Continuous casting billet specificationLarge round billet, pulling speed control target: 0.17+/-0.02 m/min. The extreme value of the carbon deviation of the cross section of the large round billet is less than or equal to 0.03%, the maximum value is less than or equal to 0.62%, and the minimum value is less than or equal to 0.59%.
(5) In the slow cooling process: the pit entering temperature is more than or equal to 550 ℃, retaining walls are arranged around the slow cooling pit, and a heat preservation cover is covered above the slow cooling pit to form a closed space. The heating temperature of the temperature-controlled slow cooling pit is 740-780 ℃, the heat preservation time is 10 hours, then the heating is stopped, the slow cooling is carried out along with the furnace, the slow cooling time is more than or equal to 48 hours, and the pit outlet temperature is less than or equal to 200 ℃.
Example 1
The chemical composition and the mass percentage content of the steel continuous casting round billet for the hot roller are shown in table 1, and the rest components are Fe and unavoidable impurities. Table 2 shows the results of the low power organization of the examples. Table 3 shows the nonmetallic inclusion grades of the respective examples. Table 4 shows the gas content of each example.
The production process of the embodiment comprises the procedures of electric furnace smelting, LF refining, VD vacuum treatment and continuous casting, and the specific process steps are as follows:
(1) Smelting in an electric furnace: the raw materials for charging are hot molten iron and high-quality scrap steel, and the proportion of molten iron is 65%; endpoint C was 0.18% and P was 0.003%; the tapping temperature is 1652 ℃. And (3) adding alloy for adjustment according to the lower limit of the components in ladle alloying, and adding 1200kg of slag forming materials.
(2) Refining: refining the components in place, wherein the content of C is 0.58%, the content of Mn is 0.86%, and the content of Cr is 1.01%. And controlling the alkalinity of slag to be 3.2, and enhancing the desulfurization operation. Before taking one sample, feeding an aluminum wire, and sampling under white slag for full component analysis. According to the analysis result of the components, the content of C, si, mn, cr, mo, al components is adjusted. Argon flow is 50NL/min in the electrifying and heating process, and argon flow before tapping is controlled at 18NL/min.
(3) Vacuum degassing: the vacuum hold time was 25 minutes. The soft blow time was 18 minutes. Controlling the steel feeding temperature after argon: continuous casting first furnace: the liquidus plus 88℃and the second furnace plus 60℃from the liquidus. The vacuum degree in the preliminary pumping period is above 67pa, and the argon blowing flow is 17NL/min; the vacuum degree is less than or equal to 67pa, and the argon blowing flow is 55NL/min. After breaking the air, 85kg of covering agent is added.
(4) Continuous casting process: adopting special covering slag for high-carbon steel, and protecting molten steel by a double-layer covering agent of a tundish to avoid sucking air; an induction heating type tundish was used, and the temperature was controlled to 1501 ℃. The continuous casting machine is a 5-machine 5-strand continuous casting machine with an arc radius of 16.5 meters, and in the casting process, the crystallizer is subjected to electromagnetic stirring, the stirring parameter is 300A, the frequency is 1.0HZ, and the specific water quantity in the secondary cooling zone is 0.99L/Kg. The temperature of the casting blank is measured by a withdrawal and straightening machine, the working pressure of the withdrawal and straightening machine is 45Mpa, the problem of warping is solved in the straightening process after the casting blank enters the withdrawal and straightening machine, the maximum deformation resistance of the casting blank is 30Mpa, and the withdrawal and straightening machine meets the requirements. Continuous casting billet specificationThe pulling speed of the large round billet is controlled to be 0.17m/min. The extreme value of the carbon deviation of the cross section of the large round billet is 0.02%, the maximum value is 0.61%, and the minimum value is 0.59%.
(5) And (3) slow cooling step: the pit entering temperature is 562 ℃, retaining walls are arranged around the slow cooling pit, and a heat preservation cover is covered above the retaining walls to form a closed space. The heating temperature of the temperature-controlled slow cooling pit is 770 ℃, the heat preservation time is 10 hours, then the heating is stopped, the slow cooling is carried out along with the slow cooling of the furnace, the slow cooling time is 53 hours, and the pit outlet temperature is 190 ℃.
Example 2
The chemical composition and the mass percentage content of the steel continuous casting round billet for the hot roller are shown in table 1, and the rest components are Fe and unavoidable impurities. Table 2 shows the results of the low power organization of the examples. Table 3 shows the nonmetallic inclusion grades of the respective examples. Table 4 shows the gas content of each example.
The production process of the embodiment comprises the procedures of electric furnace smelting, LF refining, VD vacuum treatment and continuous casting, and the specific process steps are as follows:
(1) Smelting in an electric furnace: the raw materials for charging are hot molten iron and high-quality scrap steel, and the proportion of molten iron is 66%; endpoint C was 0.19% and P was 0.005%; the tapping temperature is 1656 ℃. The ladle alloying is regulated by adding alloy according to the lower limit of the components, and 1410kg of slag forming material is added.
(2) Refining: refining in-place components, wherein the content of C is 0.60%, the content of Mn is 0.88%, and the content of Cr is 0.99%. And controlling the alkalinity of slag to be 3.3, and enhancing the desulfurization operation. Before taking one sample, feeding an aluminum wire, and sampling under white slag for full component analysis. According to the analysis result of the components, the content of C, si, mn, cr, mo, al components is adjusted. Argon flow is 62NL/min in the electrifying and heating process, and argon flow before tapping is controlled at 21NL/min.
(3) Vacuum degassing: the vacuum hold time was 26 minutes. The soft blow time was 17 minutes. Controlling the steel feeding temperature after argon: continuous casting first furnace: the liquidus plus 85℃and the second furnace plus 53 ℃. The vacuum degree in the preliminary pumping period is above 67pa, and the argon blowing flow is 22NL/min; the vacuum degree is less than or equal to 67pa, and the argon blowing flow is 76NL/min. 79kg of covering agent is added after the air break.
(4) Continuous casting process: adopting special covering slag for high-carbon steel, and protecting molten steel by a double-layer covering agent of a tundish to avoid sucking air; an induction heating tundish was used and the temperature was controlled at 1500 ℃. The continuous casting machine is a 5-machine 5-strand continuous casting machine with an arc radius of 16.5 meters, and in the casting process, the crystallizer is subjected to electromagnetic stirring, the stirring parameter is 300A, the frequency is 1.0HZ, and the specific water quantity in the secondary cooling zone is 1.0L/Kg. The temperature of the casting blank is measured by a withdrawal and straightening machine, the temperature is 920 ℃, the working pressure of the withdrawal and straightening machine is 43Mpa, the problem of warping is solved in the straightening process after the casting blank enters the withdrawal and straightening machine, the maximum deformation resistance is 35Mpa, and the withdrawal and straightening machine meets the requirements. Continuous casting billet specificationThe pulling speed of the large round billet is controlled to be 0.18m/min. The extreme value of the carbon deviation of the cross section of the large round billet is 0.03%, the maximum value is 0.62%, and the minimum value is 0.59%.
(5) And (3) slow cooling step: the pit entering temperature is 571 ℃, retaining walls are arranged around the slow cooling pit, and a heat preservation cover is covered above the retaining walls to form a closed space. The heating temperature of the temperature-controlled slow cooling pit is 775 ℃, the heat preservation time is 10 hours, then the heating is stopped, the slow cooling is carried out along with the furnace, the slow cooling time is 55 hours, and the pit outlet temperature is 187 ℃.
Example 3
The chemical composition and the mass percentage content of the steel continuous casting round billet for the hot roller are shown in table 1, and the rest components are Fe and unavoidable impurities. Table 2 shows the results of the low power organization of the examples. Table 3 shows the nonmetallic inclusion grades of the respective examples. Table 4 shows the gas content of each example.
The production process of the embodiment comprises the procedures of electric furnace smelting, LF refining, VD vacuum treatment and continuous casting, and the specific process steps are as follows:
(1) Smelting in an electric furnace: the raw materials for charging are hot molten iron and high-quality scrap steel, and the proportion of molten iron is 68%; endpoint C was 0.20% and P was 0.004%; the tapping temperature is 1660 ℃. The ladle alloying is regulated by adding alloy according to the lower limit of the components, and 1400kg of slag forming materials are added.
(2) Refining: refining the components in place, wherein the content of C is 0.56%, the content of Mn is 0.88%, and the content of Cr is 1.02%. And controlling the alkalinity of slag to be 3.1, and enhancing the desulfurization operation. Before taking one sample, feeding an aluminum wire, and sampling under white slag for full component analysis. According to the analysis result of the components, the content of C, si, mn, cr, mo, al components is adjusted. The argon flow rate in the electrifying and heating process is 52NL/min, and the argon flow rate before tapping is controlled at 23NL/min.
(3) Vacuum degassing: the vacuum hold time was 27 minutes. The soft blow time was 19 minutes. Controlling the steel feeding temperature after argon: continuous casting first furnace: the liquidus plus 89 ℃ and the second furnace plus 70 ℃ from the liquidus. The vacuum degree in the preliminary pumping period is above 67pa, and the argon blowing flow is 18NL/min; the vacuum degree is less than or equal to 67pa, and the argon blowing flow is 57NL/min. 90kg of covering agent is added after the air break.
(4) Continuous casting process: adopting special covering slag for high-carbon steel, and protecting molten steel by a double-layer covering agent of a tundish to avoid sucking air; usingThe temperature of the induction heating type tundish is controlled to be 1510 ℃. The continuous casting machine is a 5-machine 5-strand continuous casting machine with an arc radius of 16.5 meters, and in the casting process, the crystallizer is subjected to electromagnetic stirring, the stirring parameter is 300A, the frequency is 1.0HZ, and the specific water quantity of the secondary cooling zone is 1.01L/Kg. The temperature of the casting blank is measured by a withdrawal and straightening machine, the working pressure of the withdrawal and straightening machine is 46Mpa, the problem of warping is solved in the straightening process after the casting blank enters the withdrawal and straightening machine, the maximum deformation resistance of the casting blank is 28Mpa, and the withdrawal and straightening machine meets the requirements. Continuous casting billet specificationThe pulling speed of the large round billet is controlled to be 0.19m/min. The extreme value of the carbon deviation of the cross section of the large round billet is 0.02%, the maximum value is 0.61%, and the minimum value is 0.59%.
(5) And (3) slow cooling step: the pit entering temperature is 559 ℃, retaining walls are arranged around the slow cooling pit, and a heat preservation cover is covered above the slow cooling pit to form a closed space. The heating temperature of the temperature-controlled slow cooling pit is 777 ℃, the heat preservation time is 10 hours, then the heating is stopped, the slow cooling is carried out along with the furnace, the slow cooling time is 58 hours, and the pit outlet temperature is 170 ℃.
Table 1 shows the chemical compositions of the steels according to the examples of the present invention
| Chemical composition | Example 1 | Example 2 | Example 3 |
| C | 0.62 | 0.62 | 0.63 |
| Si | 0.30 | 0.29 | 0.31 |
| Mn | 0.92 | 0.91 | 0.90 |
| P | 0.010 | 0.012 | 0.011 |
| S | 0.003 | 0.005 | 0.003 |
| Cr | 1.03 | 1.05 | 1.04 |
| Mo | 0.21 | 0.22 | 0.21 |
| Alt | 0.022 | 0.027 | 0.031 |
Table 2 shows the microstructure of a steel continuous casting round billet for hot rolls
| Specification of specification | Center porosity | Shrinkage cavity | Center crack | Intermediate crack | |
| Standard of | Grade less than or equal to 2.0 | Grade less than or equal to 1.5 | Grade less than or equal to 2.0 | < 1.0 grade | |
| Example 1 | Φ800mm | 0.5 | 0.5 | 0.5 | 0 |
| Example 2 | Φ800mm | 0.5 | 1.0 | 0.5 | 0 |
| Example 3 | Φ800mm | 0.5 | 0.5 | 0.5 | 0 |
Table 3 shows the grade of nonmetallic inclusion in steel continuous casting round billet for hot roll
Table 4 shows the gas content of steel continuous casting round billet for hot roll
| Oxygen content | Hydrogen content | Nitrogen content | |
| Standard of | ≤15ppm | ≤1.5ppm | ≤90ppm |
| Example 1 | 12 | 1.1 | 55 |
| Example 2 | 10 | 1.0 | 61 |
| Example 3 | 10 | 1.2 | 49 |
The invention may be practiced without these specific details, using any knowledge known in the art.
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and are not limiting. Although the present invention has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the present invention, which is intended to be covered by the appended claims.
Claims (7)
1. A method for manufacturing a steel round billet for a high-carbon low-alloy hot roll, comprising the following steps:
1) In the electric furnace smelting process: the proportion of molten iron is more than 60 percent; endpoint C is more than or equal to 0.15%, P is less than or equal to 0.007%;
2) Refining in a refining furnace: refining in-place components, wherein the content of C is more than or equal to a target value of 0.56%, the content of Mn is more than or equal to a target value of 0.84%, the content of Cr is more than or equal to a target value of 0.99%, the flow rate of argon in the process of electrifying and heating is 40-80NL/min, and the flow rate of argon before tapping is controlled at 10-30NL/min;
3) Vacuum degassing in a VD furnace:
controlling the steel feeding temperature after argon: continuous casting first furnace: the liquidus is added with 80-105 ℃, and the liquidus is added with 55-80 ℃ for the second furnace;
argon blowing flow rate: 10-30NL/min; vacuum degree is less than or equal to 67pa, argon blowing flow rate: 50-100NL/min; after the air is broken, adding a covering agent;
4) In the continuous casting process: the control temperature of the heat is 1491-1511 ℃; casting, namely, feeding the casting into a withdrawal and straightening machine to measure the temperature, wherein the temperature is more than or equal to 915 ℃, and the working pressure of the withdrawal and straightening machine is less than or equal to 50Mpa; wherein, the crystallizer is stirred electromagnetically, the stirring parameter is 200-300A, the frequency is 0.9-1.1HZ, and the specific water quantity in the secondary cooling zone is 0.98-1.02L/Kg; the maximum deformation resistance of the casting blank is less than or equal to 40Mpa in the straightening process after the casting blank enters a withdrawal and straightening machine; continuous casting blank specification phi 800mm large round blank, drawing speed control target: 0.17+/-0.02 m/min, the extreme value of the carbon deviation of the cross section of the large round billet is less than or equal to 0.03%, the maximum value is less than or equal to 0.62%, and the minimum value is less than or equal to 0.59%;
5) In the slow cooling process: the pit entering temperature is more than or equal to 550 ℃, and the pit exiting temperature is less than or equal to 200 ℃.
2. The method for manufacturing the steel round billet for the high-carbon low-alloy hot roll according to claim 1, wherein in the step 1), hot molten iron and high-quality scrap steel are added as raw materials, and the tapping temperature is more than or equal to 1600 ℃; and (3) alloying the steel ladle, adding alloy according to the lower limit of the components, and adding 1100-1650kg of slag forming materials.
3. The method for manufacturing a steel round billet for high-carbon low-alloy hot rolls according to claim 1, wherein in the step 2), the basicity of slag is controlled to be more than 3.0, before taking a sample, an aluminum wire is fed, the sample is taken under white slag for full component analysis, and the component content of C, si, mn, cr, mo, al is adjusted according to the component analysis result.
4. The method for manufacturing a round steel billet for high-carbon low-alloy hot rolls according to claim 1, wherein the slag is removed before VD in the step 3), and the amount of the removed slag is about 1/5; the vacuum holding time is more than or equal to 22 minutes, and the soft blowing time is more than or equal to 15 minutes; the vacuum degree in the preliminary pumping period is more than 67 pa; 70-100kg of covering agent is added after the air break.
5. The method for manufacturing the steel round billet for the high-carbon low-alloy hot roll according to claim 1, wherein the step 4) adopts the special covering slag for the high-carbon steel, and the tundish double-layer covering agent is used for protecting molten steel; using an induction heating tundish; the continuous casting machine is a 5-machine 5-strand continuous casting machine with an arc radius of 16.5 meters.
6. The method for manufacturing the steel round billet for the high-carbon low-alloy hot roller, which is disclosed in claim 1, is characterized in that retaining walls are arranged around the slow cooling pit in the step 5), a heat preservation cover is covered above the retaining walls to form a closed space, the heating temperature of the temperature-controlled slow cooling pit is 740-780 ℃, the heat preservation time is more than or equal to 10 hours, then the heating is stopped, the slow cooling is carried out along with the furnace, and the slow cooling time is more than or equal to 48 hours.
7. The method for manufacturing a steel round billet for high-carbon low-alloy hot rolls according to claim 1, wherein the oxygen content of the steel round billet for high-carbon low-alloy hot rolls is 15ppm or less; the hydrogen content is less than or equal to 1.5ppm; nitrogen is less than or equal to 90ppm; the central porosity is less than or equal to 2.0 level, the shrinkage cavity is less than or equal to 1.5 level, the central crack is less than or equal to 2.0 level, and the middle crack is less than 1.0 level.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102936689A (en) * | 2012-11-23 | 2013-02-20 | 中天钢铁集团有限公司 | High-temperature-resistant bearing steel and production process thereof |
| CN103898413A (en) * | 2014-03-18 | 2014-07-02 | 莱芜钢铁集团有限公司 | Steel for nitrogen vanadium microalloyed grinding rod and preparation method thereof |
| CN104762562A (en) * | 2015-04-23 | 2015-07-08 | 山东钢铁股份有限公司 | Steel for large-diameter grinding balls and preparation method of steel |
| CN105537549A (en) * | 2015-12-14 | 2016-05-04 | 攀钢集团成都钢钒有限公司 | Production method of continuous casting round billet of seamless steel tube steel at low temperature of minus 100 DEG C |
| CN106563780A (en) * | 2016-10-31 | 2017-04-19 | 山东钢铁股份有限公司 | Continuous casting method for big round billet of medium-high-carbon medium-high-alloy tool steel |
| CN108728606A (en) * | 2018-05-09 | 2018-11-02 | 石家庄钢铁有限责任公司 | A kind of production technology of cold roller steel electroslag blank |
| CN110230005A (en) * | 2019-05-22 | 2019-09-13 | 山东钢铁股份有限公司 | A kind of high carbon chromium cold roll blank steel and preparation method thereof |
| CN113817951A (en) * | 2021-08-23 | 2021-12-21 | 南京钢铁股份有限公司 | Production process of continuous casting gear steel bar for rail transit |
-
2022
- 2022-10-14 CN CN202211258925.7A patent/CN115652181B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102936689A (en) * | 2012-11-23 | 2013-02-20 | 中天钢铁集团有限公司 | High-temperature-resistant bearing steel and production process thereof |
| CN103898413A (en) * | 2014-03-18 | 2014-07-02 | 莱芜钢铁集团有限公司 | Steel for nitrogen vanadium microalloyed grinding rod and preparation method thereof |
| CN104762562A (en) * | 2015-04-23 | 2015-07-08 | 山东钢铁股份有限公司 | Steel for large-diameter grinding balls and preparation method of steel |
| CN105537549A (en) * | 2015-12-14 | 2016-05-04 | 攀钢集团成都钢钒有限公司 | Production method of continuous casting round billet of seamless steel tube steel at low temperature of minus 100 DEG C |
| CN106563780A (en) * | 2016-10-31 | 2017-04-19 | 山东钢铁股份有限公司 | Continuous casting method for big round billet of medium-high-carbon medium-high-alloy tool steel |
| CN108728606A (en) * | 2018-05-09 | 2018-11-02 | 石家庄钢铁有限责任公司 | A kind of production technology of cold roller steel electroslag blank |
| CN110230005A (en) * | 2019-05-22 | 2019-09-13 | 山东钢铁股份有限公司 | A kind of high carbon chromium cold roll blank steel and preparation method thereof |
| CN113817951A (en) * | 2021-08-23 | 2021-12-21 | 南京钢铁股份有限公司 | Production process of continuous casting gear steel bar for rail transit |
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