CN117737561A - Smelting production process of seamless steel tube round billet for rare earth 770 MPa-level crane boom - Google Patents
Smelting production process of seamless steel tube round billet for rare earth 770 MPa-level crane boom Download PDFInfo
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- CN117737561A CN117737561A CN202311496920.2A CN202311496920A CN117737561A CN 117737561 A CN117737561 A CN 117737561A CN 202311496920 A CN202311496920 A CN 202311496920A CN 117737561 A CN117737561 A CN 117737561A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 66
- 239000010959 steel Substances 0.000 title claims abstract description 66
- 229910052761 rare earth metal Inorganic materials 0.000 title claims abstract description 25
- 238000003723 Smelting Methods 0.000 title claims abstract description 23
- 150000002910 rare earth metals Chemical class 0.000 title claims abstract description 22
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 11
- 238000000034 method Methods 0.000 claims abstract description 41
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 38
- 238000005266 casting Methods 0.000 claims abstract description 19
- 229910052742 iron Inorganic materials 0.000 claims abstract description 18
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000001301 oxygen Substances 0.000 claims abstract description 15
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 15
- 238000009628 steelmaking Methods 0.000 claims abstract description 4
- 239000002893 slag Substances 0.000 claims description 36
- 238000010079 rubber tapping Methods 0.000 claims description 18
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 12
- 238000003756 stirring Methods 0.000 claims description 12
- 238000009749 continuous casting Methods 0.000 claims description 9
- 238000006477 desulfuration reaction Methods 0.000 claims description 9
- 230000023556 desulfurization Effects 0.000 claims description 9
- 238000007670 refining Methods 0.000 claims description 9
- 238000010583 slow cooling Methods 0.000 claims description 9
- 238000007664 blowing Methods 0.000 claims description 8
- 238000009489 vacuum treatment Methods 0.000 claims description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 6
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 6
- 229910000604 Ferrochrome Inorganic materials 0.000 claims description 6
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 6
- 229910052786 argon Inorganic materials 0.000 claims description 6
- 239000011575 calcium Substances 0.000 claims description 6
- 229910052791 calcium Inorganic materials 0.000 claims description 6
- 229910052799 carbon Inorganic materials 0.000 claims description 6
- 239000004571 lime Substances 0.000 claims description 6
- 229910052698 phosphorus Inorganic materials 0.000 claims description 6
- 239000012535 impurity Substances 0.000 claims description 5
- 229910000640 Fe alloy Inorganic materials 0.000 claims description 4
- GSVIBLVMWGSPRZ-UHFFFAOYSA-N cerium iron Chemical compound [Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Ce].[Ce] GSVIBLVMWGSPRZ-UHFFFAOYSA-N 0.000 claims description 4
- 230000000694 effects Effects 0.000 claims description 4
- 229910000616 Ferromanganese Inorganic materials 0.000 claims description 3
- 229910001309 Ferromolybdenum Inorganic materials 0.000 claims description 3
- 229910000519 Ferrosilicon Inorganic materials 0.000 claims description 3
- 229910000628 Ferrovanadium Inorganic materials 0.000 claims description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 3
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 3
- 238000005275 alloying Methods 0.000 claims description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 3
- 229910052782 aluminium Inorganic materials 0.000 claims description 3
- 230000015572 biosynthetic process Effects 0.000 claims description 3
- 238000009835 boiling Methods 0.000 claims description 3
- 239000003795 chemical substances by application Substances 0.000 claims description 3
- 238000007599 discharging Methods 0.000 claims description 3
- 229910000514 dolomite Inorganic materials 0.000 claims description 3
- 239000010459 dolomite Substances 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 3
- 239000001257 hydrogen Substances 0.000 claims description 3
- 229910052739 hydrogen Inorganic materials 0.000 claims description 3
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 claims description 3
- PNXOJQQRXBVKEX-UHFFFAOYSA-N iron vanadium Chemical compound [V].[Fe] PNXOJQQRXBVKEX-UHFFFAOYSA-N 0.000 claims description 3
- 238000005502 peroxidation Methods 0.000 claims description 3
- 239000011574 phosphorus Substances 0.000 claims description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 2
- 238000012545 processing Methods 0.000 claims description 2
- 238000005728 strengthening Methods 0.000 claims description 2
- 238000005516 engineering process Methods 0.000 abstract description 5
- 239000007789 gas Substances 0.000 description 6
- 238000012360 testing method Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 238000003466 welding Methods 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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- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention discloses a smelting production process of a seamless steel tube round billet for a 770 MPa-level rare earth-containing crane boom, which adopts the following round billet steelmaking process flow: blast furnace molten iron-molten iron pretreatment-converter smelting-LF external refining-VD vacuum treatment-continuous casting-casting blank slow cooling-warehousing. The rare earth element added in the process can effectively remove oxygen in the steel, and has high affinity with the oxygen element in the molten steel, thus having good molten steel purifying capability. And the clean steel smelting technology plays an important role in the high quality and high performance of the boom pipe.
Description
Technical Field
The invention relates to the technical field of seamless steel tube production, in particular to a smelting production process of a seamless steel tube round billet for a 770 MPa-level rare earth-containing crane boom.
Background
In order to improve the lifting performance and the safety of the whole crane and meet the requirements of lightweight design of the boom, the development of a low-alloy high-strength boom pipe with high strength, high toughness and good welding performance is a necessary choice. The circular boom pipe blank smelting process is a key technology and key problem in industrial production application, the beneficial effect of rare earth purification of molten steel is exerted by depending on the existing smelting conditions of a steel pipe company, and a seamless steel pipe circular blank smelting process method for the crane boom containing the rare earth 770MPa level is formulated.
Disclosure of Invention
The invention aims to provide a smelting production process of a seamless steel tube round billet for a 770 MPa-level crane boom containing rare earth, which improves the steel purity of the steel tube round billet.
In order to solve the technical problems, the invention adopts the following technical scheme:
the invention relates to a smelting production process of a seamless steel tube round billet for a 770 MPa-level rare earth-containing crane boom, which adopts the following round billet steelmaking process flow: the method is characterized by comprising the following specific processes of blast furnace molten iron-molten iron pretreatment-converter smelting-LF external refining-VD vacuum treatment-continuous casting-casting blank slow cooling-warehousing:
during pretreatment of molten iron, magnesium powder is sprayed into steel to perform molten iron pre-desulfurization and dephosphorization, wherein the temperature of the molten iron is 1300+/-20 ℃;
charging pretreated molten iron and scrap steel with a slag former, and reducing phosphorus in steel through blowing by an oxygen lance; the final slag alkalinity of converter smelting is more than 3.0, the content of terminal carbon is controlled, peroxidation and ultra-low carbon tapping cannot be carried out, the control target of the converter terminal is C not less than 0.06%, P is not more than 0.015%, and the tapping temperature is controlled at 1610-1630 ℃;
deoxidizing and alloying ferrosilicon, ferromanganese and ferrochromium, and finally deoxidizing by adopting an aluminum deoxidizing process; adding a proper amount of lime in the tapping process, strictly controlling the slag discharging amount in the tapping process, and stopping slag when slag stopping failure occurs in tapping, and performing slag skimming;
LF external refining carries out slag formation desulfurization, component adjustment and heating operation according to the components and the temperature of the converter molten steel; raising the temperature in a mode of gradually increasing the temperature raising speed from a low level to a high level; strengthening deoxidization operation, making white slag, keeping the white slag for 18-22min, and adjusting slag conditions according to conditions so as to ensure tapping of the white slag; adding ferromolybdenum, ferrovanadium and ferrochromium in the middle and later stages of refining; feeding a proper amount of high-calcium wires before refining; the high-calcium line realizes the purposes of deoxidization, desulfurization, uniform temperature and impurity removal;
vacuum processing is carried out on VD, after the VD is in place, rare earth cerium-iron alloy is added by adopting an input method, the vacuum degree is less than or equal to 0.10KPa, the target value is less than or equal to 0.06KPa, and the deep vacuum time is more than or equal to 15min;
the soft blowing time after vacuum treatment is more than or equal to 13min, meanwhile, the weak stirring effect is required to be noted, and molten steel cannot be exposed; after VD vacuum treatment, the total oxygen in the steel is lower than 30ppm;
the whole-course protection casting is adopted in the continuous casting process, and the pulling speed of 1.5m/min is strictly controlled according to the steel grade and the blank shape, so that the constant pulling speed casting is ensured; stirring by adopting a crystallizer electromagnetic stirring process and a terminal electromagnetic stirring process, wherein the superheat degree of molten steel in the continuous casting process is controlled to be 15-35 ℃, and the liquidus temperature of the steel is 1509 ℃;
the casting blank is fed into a slow cooling pit in time for slow cooling, the slow cooling time is more than 48 hours, and the pipe blank can be taken out of the pit and conveyed after the temperature is reduced to below 100 ℃.
Further, the molten iron temperature was 1300 ℃.
Further, the slag former comprises lime and dolomite.
Further, the boiling condition of molten steel is noticed at any time in the vacuumizing process, the argon gas is blown from the bottom of the steel ladle to remove hydrogen and oxygen elements in the steel, and the flow of the argon gas is adjusted in time.
Furthermore, the baking of the ladle and the tundish is required to be enhanced in the round billet continuous casting process, the casting system must be ensured to be clean and dry, and the tundish covering agent and the crystallizer casting powder must be kept dry.
Further, the smelting components comprise, by mass, 0.16% of C, 0.39% of Si, 1.35% of Mn, 0.01% of P, 0.003% of S, 0.35% of Ni, 0.71% of Cr, 0.28% of Mo, 0.42% of Al, 0.03% of V, 0.01% of RE, and the balance of Fe and unavoidable impurities.
Compared with the prior art, the invention has the beneficial technical effects that:
the rare earth element added in the invention can effectively remove oxygen in the steel, and has high affinity with oxygen element in the molten steel, thus having better molten steel purifying capability. And the clean steel smelting technology plays an important role in the high quality and high performance of the boom pipe.
Drawings
The invention is further described with reference to the following description of the drawings.
Fig. 1 is a photograph of a 770MPa low-power tissue of the boom pipe.
Detailed Description
A smelting production process of a seamless steel tube round billet for a 770 MPa-level rare earth-containing crane boom adopts the following round billet steelmaking process flow: blast furnace molten iron-molten iron pretreatment-converter smelting-LF external refining-VD vacuum treatment-continuous casting-casting blank slow cooling-warehousing.
And during molten iron pretreatment, magnesium powder is sprayed into the steel to perform molten iron pre-desulfurization and dephosphorization, wherein the temperature of the molten iron is 1300 ℃.
And (3) charging pretreated molten iron and scrap steel together with slag formers such as lime, dolomite and the like into a furnace, and reducing phosphorus in the steel through blowing by an oxygen lance. The final slag alkalinity of converter smelting is more than 3.0, the content of terminal carbon is controlled, peroxidation and ultra-low carbon tapping cannot be carried out, the control target of the converter terminal is C not less than 0.06%, P is not more than 0.015%, and the tapping temperature is controlled at 1610-1630 ℃;
adopts ferrosilicon, ferromanganese and ferrochromium to carry out deoxidization alloying, and finally adopts aluminum deoxidization technology. Proper lime is added in the tapping process, the slag discharging amount in the tapping process is strictly controlled, slag is blocked in tapping, and slag skimming is required if slag blocking fails.
LF external refining carries out slag formation desulfurization, component adjustment and heating operation according to the components and the temperature of the converter molten steel; raising the temperature in a mode of gradually increasing the temperature raising speed from a low level to a high level; reinforcing deoxidization operation, making white slag, keeping the white slag for 20min, and adjusting slag conditions according to conditions so as to ensure tapping of the white slag; ferromolybdenum, ferrovanadium and ferrochromium are added in the middle and later stages of refining. And feeding a proper amount of high-calcium wires before refining is finished. The high-calcium line realizes the purposes of deoxidization, desulfurization, uniform temperature and impurity removal.
And (3) performing vacuum treatment on the VD, and adding rare earth cerium-iron alloy by adopting an input method after the VD is in place, wherein the vacuum degree is less than or equal to 0.10KPa, and the target value is less than or equal to 0.06KPa. The deep vacuum time is more than or equal to 15min, the boiling condition of molten steel is noted at any time in the vacuumizing process, the steel ladle bottom blowing argon is treated to remove elements such as hydrogen, oxygen and the like, and the flow of argon is adjusted in time.
The soft blowing time after vacuum treatment is more than or equal to 13min, and meanwhile, the weak stirring effect is required to be noted, so that molten steel cannot be exposed. Because the steel has strict requirements on nonmetallic inclusion, low-power tissues and the like, the nonmetallic inclusion in the molten steel must be removed. After VD vacuum treatment, the total oxygen in the steel is less than 30ppm.
In the round billet continuous casting process, the baking of the ladle and the tundish is required to be enhanced, the casting system must be ensured to be clean and dry, and the tundish covering agent and the crystallizer casting powder must be kept dry. The whole-course protection pouring is adopted in the continuous casting process, and the pulling speed of 1.5m/min is strictly controlled according to the steel grade and the blank shape, so that the constant pulling speed pouring is ensured. Stirring by adopting a crystallizer electromagnetic stirring process and a terminal electromagnetic stirring process, wherein the superheat degree of molten steel in the continuous casting process is controlled to be 15-35 ℃, and the liquidus temperature of the steel is 1509 ℃.
The casting blank of the steel grade is fed into a slow cooling pit in time for slow cooling, the slow cooling time is more than 48 hours, and the pipe blank can be taken out of the pit and conveyed after the temperature is reduced to below 100 ℃.
Test
Two sets of tests were designed, one without rare earth addition and one with 10ppm rare earth addition, and the two sets of test components and gas contents are shown in tables 1 and 2.
No. 1 sample was free of rare earth elements, and the oxygen content of the gas in the steel was 0.026. The No. 2 sample is smelted by adopting a control technology of adding inclusions such as rare earth cerium-iron alloy, and the oxygen content of gas in steel is 0.016. Compared with the rare earth which is not added, the method is reduced by 38%, the morphology of the low-power structure of the casting blank is shown in the figure 1, and the detection result shows that the center of the casting blank is loose by 0.5 level, the shrinkage cavity is 1 level, no other defects are found, and the quality of the casting blank is good.
Table 1 770MPa melting component (mass fraction)
TABLE 2 gas content/%
The above embodiments are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope defined by the claims of the present invention without departing from the design spirit of the present invention.
Claims (6)
1. A smelting production process of a seamless steel tube round billet for a 770 MPa-level rare earth-containing crane boom adopts the following round billet steelmaking process flow: the method is characterized by comprising the following specific processes of blast furnace molten iron-molten iron pretreatment-converter smelting-LF external refining-VD vacuum treatment-continuous casting-casting blank slow cooling-warehousing:
during pretreatment of molten iron, magnesium powder is sprayed into steel to perform molten iron pre-desulfurization and dephosphorization, wherein the temperature of the molten iron is 1300+/-20 ℃;
charging pretreated molten iron and scrap steel with a slag former, and reducing phosphorus in steel through blowing by an oxygen lance; the final slag alkalinity of converter smelting is more than 3.0, the content of terminal carbon is controlled, peroxidation and ultra-low carbon tapping cannot be carried out, the control target of the converter terminal is C not less than 0.06%, P is not more than 0.015%, and the tapping temperature is controlled at 1610-1630 ℃;
deoxidizing and alloying ferrosilicon, ferromanganese and ferrochromium, and finally deoxidizing by adopting an aluminum deoxidizing process; adding a proper amount of lime in the tapping process, strictly controlling the slag discharging amount in the tapping process, and stopping slag when slag stopping failure occurs in tapping, and performing slag skimming;
LF external refining carries out slag formation desulfurization, component adjustment and heating operation according to the components and the temperature of the converter molten steel; raising the temperature in a mode of gradually increasing the temperature raising speed from a low level to a high level; strengthening deoxidization operation, making white slag, keeping the white slag for 18-22min, and adjusting slag conditions according to conditions so as to ensure tapping of the white slag; adding ferromolybdenum, ferrovanadium and ferrochromium in the middle and later stages of refining; feeding a proper amount of high-calcium wires before refining; the high-calcium line realizes the purposes of deoxidization, desulfurization, uniform temperature and impurity removal;
vacuum processing is carried out on VD, after the VD is in place, rare earth cerium-iron alloy is added by adopting an input method, the vacuum degree is less than or equal to 0.10KPa, the target value is less than or equal to 0.06KPa, and the deep vacuum time is more than or equal to 15min;
the soft blowing time after vacuum treatment is more than or equal to 13min, meanwhile, the weak stirring effect is required to be noted, and molten steel cannot be exposed; after VD vacuum treatment, the total oxygen in the steel is lower than 30ppm;
the whole-course protection casting is adopted in the continuous casting process, and the pulling speed of 1.5m/min is strictly controlled according to the steel grade and the blank shape, so that the constant pulling speed casting is ensured; stirring by adopting a crystallizer electromagnetic stirring process and a terminal electromagnetic stirring process, wherein the superheat degree of molten steel in the continuous casting process is controlled to be 15-35 ℃, and the liquidus temperature of the steel is 1509 ℃;
the casting blank is fed into a slow cooling pit in time for slow cooling, the slow cooling time is more than 48 hours, and the pipe blank can be taken out of the pit and conveyed after the temperature is reduced to below 100 ℃.
2. The process for smelting and producing the seamless steel tube round billet for the crane boom containing the rare earth 770MPa grade according to claim 1, wherein the temperature of molten iron is 1300 ℃.
3. The smelting production process of the seamless steel tube round billet for the rare earth 770 MPa-level crane boom according to claim 1, wherein the slag former comprises lime and dolomite.
4. The process for smelting the seamless steel tube round billet for the crane boom containing the rare earth 770MPa grade according to claim 1, wherein the boiling condition of molten steel is noticed at any time in the vacuumizing process, the hydrogen and oxygen elements in the steel are removed by the ladle bottom blowing argon treatment, and the flow of argon is adjusted in time.
5. The process for smelting round billets of seamless steel tubes for the crane boom containing rare earth 770MPa grade according to claim 1, wherein the baking of the upper ladle and the middle ladle is required to be enhanced in the round billet continuous casting process, the casting system is required to ensure clean and dry, and the middle ladle covering agent and the crystallizer covering slag are required to be kept dry.
6. The smelting production process of the seamless steel tube round billet for the crane boom containing the rare earth 770MPa grade according to claim 1, wherein the smelting components comprise, by mass, 0.16% of C, 0.39% of Si, 1.35% of Mn, 0.01% of P, 0.003% of S, 0.35% of Ni, 0.71% of Cr, 0.28% of Mo, 0.42% of Al, 0.03% of V, 0.01% of RE, and the balance of Fe and unavoidable impurities.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311496920.2A CN117737561A (en) | 2023-11-10 | 2023-11-10 | Smelting production process of seamless steel tube round billet for rare earth 770 MPa-level crane boom |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311496920.2A CN117737561A (en) | 2023-11-10 | 2023-11-10 | Smelting production process of seamless steel tube round billet for rare earth 770 MPa-level crane boom |
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| Publication Number | Publication Date |
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| CN117737561A true CN117737561A (en) | 2024-03-22 |
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| CN202311496920.2A Pending CN117737561A (en) | 2023-11-10 | 2023-11-10 | Smelting production process of seamless steel tube round billet for rare earth 770 MPa-level crane boom |
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| Country | Link |
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| CN (1) | CN117737561A (en) |
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