CN113621758A - Control method and application of Ds inclusion in steelmaking continuous casting process - Google Patents
Control method and application of Ds inclusion in steelmaking continuous casting process Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 78
- 238000009628 steelmaking Methods 0.000 title claims abstract description 30
- 238000009749 continuous casting Methods 0.000 title claims abstract description 28
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 185
- 239000010959 steel Substances 0.000 claims abstract description 185
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims abstract description 48
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 48
- 239000011575 calcium Substances 0.000 claims abstract description 48
- 238000005266 casting Methods 0.000 claims abstract description 37
- 238000010438 heat treatment Methods 0.000 claims abstract description 23
- 238000003756 stirring Methods 0.000 claims abstract description 13
- 238000009489 vacuum treatment Methods 0.000 claims abstract description 13
- 238000003780 insertion Methods 0.000 claims abstract description 10
- 230000037431 insertion Effects 0.000 claims abstract description 10
- 238000007664 blowing Methods 0.000 claims abstract description 9
- 238000004321 preservation Methods 0.000 claims abstract description 8
- 238000007711 solidification Methods 0.000 claims abstract description 7
- 230000008023 solidification Effects 0.000 claims abstract description 7
- 239000002893 slag Substances 0.000 claims description 22
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 21
- 229910052782 aluminium Inorganic materials 0.000 claims description 21
- 230000006698 induction Effects 0.000 claims description 20
- 239000003795 chemical substances by application Substances 0.000 claims description 12
- 229910000532 Deoxidized steel Inorganic materials 0.000 claims description 11
- 235000007164 Oryza sativa Nutrition 0.000 claims description 6
- 235000009566 rice Nutrition 0.000 claims description 6
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 5
- 229910052749 magnesium Inorganic materials 0.000 claims description 5
- 239000011777 magnesium Substances 0.000 claims description 5
- 239000011819 refractory material Substances 0.000 claims description 5
- ULGYAEQHFNJYML-UHFFFAOYSA-N [AlH3].[Ca] Chemical compound [AlH3].[Ca] ULGYAEQHFNJYML-UHFFFAOYSA-N 0.000 claims description 2
- 240000007594 Oryza sativa Species 0.000 claims 1
- 239000004411 aluminium Substances 0.000 claims 1
- 238000009413 insulation Methods 0.000 claims 1
- 239000012535 impurity Substances 0.000 description 8
- 238000009849 vacuum degassing Methods 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 6
- 238000007670 refining Methods 0.000 description 6
- 241000209094 Oryza Species 0.000 description 5
- 238000003723 Smelting Methods 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 238000007667 floating Methods 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 3
- 238000009529 body temperature measurement Methods 0.000 description 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 239000011651 chromium Substances 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 238000004886 process control Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- RGKMZNDDOBAZGW-UHFFFAOYSA-N aluminum calcium Chemical compound [Al].[Ca] RGKMZNDDOBAZGW-UHFFFAOYSA-N 0.000 description 2
- SNAAJJQQZSMGQD-UHFFFAOYSA-N aluminum magnesium Chemical compound [Mg].[Al] SNAAJJQQZSMGQD-UHFFFAOYSA-N 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 238000010273 cold forging Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- -1 magnesium-aluminum-calcium Chemical compound 0.000 description 2
- 230000024121 nodulation Effects 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 230000001502 supplementing effect Effects 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- VNTLIPZTSJSULJ-UHFFFAOYSA-N chromium molybdenum Chemical group [Cr].[Mo] VNTLIPZTSJSULJ-UHFFFAOYSA-N 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000005674 electromagnetic induction Effects 0.000 description 1
- 230000003031 feeding effect Effects 0.000 description 1
- 239000010903 husk Substances 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000009991 scouring Methods 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/111—Treating the molten metal by using protecting powders
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/116—Refining the metal
-
- 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
- B22D11/181—Controlling or regulating processes or operations for pouring responsive to molten metal level or slag level
- B22D11/182—Controlling or regulating processes or operations for pouring responsive to molten metal level or slag level by measuring temperature
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
- B22D41/50—Pouring-nozzles
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0056—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 using cored wires
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention discloses a control method and application of Ds inclusion in a steel-making casting process, wherein the method comprises the following steps: 1) after the vacuum treatment in the steelmaking process is finished, finely adjusting the components of the molten steel to meet the product requirements, feeding a small amount of calcium to adjust the calcium content of the molten steel, slightly stirring the molten steel for 3-5min after calcium feeding, and controlling the calcium content of the molten steel to be 2-5ppm before continuous casting; 2) standing molten steel in a steel ladle, wherein the molten steel is subjected to heat preservation in the standing process, bottom blowing stirring is strictly forbidden in the standing process, and the standing time is 50-90 min; 3) molten steel is adjusted to a continuous casting station for casting, the tundish needs to continuously measure the temperature in the casting process, the casting temperature is stably controlled at 15-30 ℃, and the molten steel is subjected to supplementary heating when necessary; 4) the molten steel reaches the crystallizer for solidification, and the molten steel is required to be drained from the tundish to a submerged nozzle of the crystallizer, and the insertion depth of the submerged nozzle is 140-170 mm.
Description
Technical Field
The invention relates to a control method of Ds inclusion in a steelmaking continuous casting process and application thereof, belonging to the technical field of steelmaking.
Background
Ds inclusions are inclusions which are not deformed in the rolling process, and because the Ds inclusions are not deformed, angular cavities between the inclusions and a steel matrix are easily formed in the rolling process, and the cavities can be crack sources and are extremely harmful to bar-line special steels such as aluminum deoxidized steel bearing steel, gear steel, cold heading steel and the like, the Ds inclusion observation size of high-end bearing steel is generally required to be less than 17 mu m, and the Ds inclusion observation size of high-end cold heading steel is required to be less than 20 mu m.
At present, the Ds inclusion is judged mainly by metallographic detection, the range of the metallographic detection is one corner of iceberg relative to the whole furnace steel, and the maximum Ds inclusion detected cannot completely represent the actual maximum inclusion in the steel, so that great risk is brought to product inclusion control, and large-particle Ds inclusion is required to be removed from a steelmaking process end comprehensively instead of being controlled by the product inclusion detection.
The Ds inclusion components are observed to find that mainly aluminum-calcium inclusion, magnesium-aluminum inclusion and magnesium-aluminum-calcium inclusion are generated, because aluminum in aluminum deoxidized steel inevitably reacts with CaO in slag and MgO in refractory materials to easily generate aluminum-calcium inclusion and magnesium-aluminum inclusion, and meanwhile, slag entrapment inevitably occurs in an LF refining process and a VD (vacuum degassing) process of vacuum treatment, and slag entrapment drops further react with molten steel to form aluminum-magnesium-calcium inclusion after entering the molten steel, which means that the Ds inclusion generated in a steelmaking process enters the molten steel inevitably, and even though measures such as slag adjustment, a deoxidation process and the like are adopted, the generation of the Ds inclusion cannot be avoided. The Chinese patent document with the application number of 201811167952.7 and the invention name of a bearing steel liquid deoxidation control method without Ds-type inclusions adopts the procedures of converter → LF → RH → CC to produce a high-carbon chromium bearing, and the steel liquid is discharged from the converterSilicon carbide is adopted to deoxidize instead of aluminum in the steel process, low-alkalinity refining slag is produced in the LF refining process, the slag surface is deoxidized by high-purity silicon carbide, free CaO in the slag is reduced, and Al in molten steel is reduced2O3The formation of inclusions, high vacuum circulation in the RH refining process and long-time soft blowing, thereby achieving the purpose of thoroughly removing Ds type inclusions in the bearing steel. The method adopts silicon deoxidation to replace aluminum deoxidation, and has the risk of overproof C-type impurities.
In order to completely remove large particle Ds inclusions, although blanks in an electric furnace process or a converter process can be used as electrodes and subjected to electroslag remelting treatment to remove the Ds inclusions, because thin film molten drops formed at the end parts of the electrodes in the electroslag process have large contact areas with slag, and the Ds inclusions can be adsorbed and removed by the slag, the electroslag treatment cost is high, the production efficiency is low, and the large-scale low-cost production of all high-end products cannot be met. The removal of Ds inclusions by vacuum remelting is the same as that by electroslag remelting, and because the cost is high and the production efficiency is low, the large-scale production of all high-end products cannot be met.
Disclosure of Invention
The invention aims to solve the technical problem of providing a control method for comprehensively removing large granular Ds inclusions in a steelmaking process by improving the stability of removing the inclusions, which is mainly suitable for the Ds inclusions in the steelmaking continuous casting process of aluminum-containing deoxidized steel with requirements on the Ds inclusions, namely point-shaped inclusions.
The technical problem to be solved can be implemented by the following technical scheme.
A method for controlling Ds inclusion, namely punctiform inclusion, in a steelmaking continuous casting process is mainly suitable for aluminum-containing deoxidized steel with requirements on the Ds inclusion, and mainly comprises the following steps:
1) after the vacuum treatment in the steelmaking process is finished, finely adjusting the components of the molten steel to meet the product requirements, feeding a small amount of calcium to adjust the calcium content of the molten steel, slightly stirring the molten steel for 3-5min after calcium feeding, and controlling the calcium content of the molten steel before continuous casting to be 2-5 ppm;
wherein, after the refining treatment in the steel-making link and the components are qualified, a small amount of calcium is fed to adjust the calcium content of the molten steel, which mainly ensures that a water gap is not blocked in the casting process, and the calcium treatment effect is ensured by slightly stirring the molten steel for 3-5min after the calcium is fed. The upper limit of the calcium content is 5ppm, considering that the corrosion of the refractory is easily caused by the excessively high calcium content of molten steel. If the nozzle is blocked, the molten steel flow field in the crystallizer and the molten steel flow field in the tundish are influenced, and the inclusion removal is not favorable, namely the Ds inclusion control is not favorable.
2) Standing molten steel in the steel ladle, wherein the standing process is subjected to heat preservation treatment (for example, the heat preservation treatment is carried out by adding carbonized rice husks to the slag surface), the standing process is strictly forbidden to carry out bottom blowing stirring, and the standing time is 50-90 min;
molten steel is adopted for standing treatment, so that the molten steel in a steel ladle does not flow any more, and thus, impurities can stably float upwards by virtue of buoyancy of the impurities, and the phenomenon that the impurities move downwards is avoided. In the conventional operation of the prior art, the inclusion is usually removed by low-blowing and slight stirring, but once molten steel is stirred, the inclusion is still in the moment of floating to be close to the interface of the steel slag and to be adsorbed by the slag, the risk of returning to the deep part of the molten steel due to the stirring of the molten steel still exists, the probability of the inclusion reaching the interface of the steel slag again becomes very low due to the slow floating speed of the inclusion, and the risk cannot be removed due to the large-particle inclusion. Of course, the standing process inevitably brings about non-uniformity of the molten steel temperature in the ladle, so that the tundish induction heating is used for compensating and stably controlling the molten steel temperature in the subsequent continuous casting process. The method is characterized in that the standing time is set to be 50-90min, the time requirement for removing inclusions is basically met, molten steel does not flow up and down in the casting process of the post-process, about 50min of action time exists from ladle adjustment to casting completion in the refining station, the step is set to be 50-90min, the whole standing time can be ensured to be 100-140min, inclusions with the diameter of 30 mu m can float up to the bottom of a slag layer at the upper part of the molten steel from the bottom of a ladle within 100min under the condition that the height of the molten steel in the ladle is less than 2.5m according to the calculation of the floating speed of the inclusions, the setting ensures that all the inclusions with the diameter of more than or equal to 30 mu m are removed, and Ds inclusions with the diameter of 30 mu m observed in a metallographic plane are about 15 mu m, so that the requirement that the Ds inclusion of the bearing steel with the highest Ds inclusion requirement level is less than 17 mu m is met. The upper limit of the set time is 90min, and the normal scheduling of production and the continuous pouring of the continuous casting process are influenced mainly by considering that the time is too long. In the actual production process, a station for placing molten steel can be newly added.
3) Adjusting molten steel to a continuous casting station for casting, wherein the tundish needs to continuously measure temperature in the casting process, and supplementing energy to the molten steel by using induction heating to ensure that the casting temperature is stably controlled at 15-30 ℃ of superheat degree;
the invention selects induction heating to compensate the temperature loss of molten steel in a ladle caused by long-time standing, stabilizes the pouring temperature through tundish induction heating, realizes pouring with low superheat degree, and selects induction heating intensity through the continuous temperature measurement result of the molten steel, thereby reasonably compensating the temperature and promoting the stable and controllable pouring temperature of the final molten steel. And the final superheat degree of the molten steel pouring temperature is controlled to be 15-30 ℃, so that the microsegregation of the continuous casting blank and the pourability of the molten steel are considered, the pouring is possibly influenced by the nozzle nodulation caused by too low superheat degree, and the adverse effect on the casting blank structure is possibly caused by too large control. The stability of pouring through controlling the mouth of a river, especially not the nodulation in pouring basket immersion nozzle department is the prerequisite of guaranteeing pouring basket flow field temperature and crystallizer flow field stability, and the flow field stability can guarantee to get rid of Ds and mix with the stability.
4) The molten steel reaches the crystallizer for solidification, and the submerged nozzle for draining the molten steel from the tundish to the crystallizer is a double-hole or four-hole nozzle, and the insertion depth of the nozzle is 140mm and 170 mm.
When the submerged nozzle is a double-hole or four-hole nozzle, the double-hole and four-hole nozzles spray double streams, so that the protective slag is ensured to be dissolved, impurities in the crystallizer can conveniently float upwards, and Ds impurities are not easily removed if a straight nozzle is used. The control of the insertion depth of 140mm and 170mm can prevent the covering slag in the crystallizer from fluctuating too violently due to too shallow insertion and prevent inclusions from floating upwards difficultly due to too deep insertion.
Finally, the molten steel is solidified into a qualified steel billet, and the total Ds inclusion of the steel billet is less than 17 mu m.
Wherein, as a further improvement of the technical proposal, in the step 1), the calcium feeding amount of the fine adjustment molten steel is controlled to be 0.03-0.05 kg/t. The control of the calcium feeding amount can ensure that the subsequent calcium content is controlled in place, and the calcium feeding amount is converted to 0.03-0.05kg/t by feeding 40-70m calcium wires in a 100-150 ton furnace.
As a further improvement of the technical scheme, in the step 1), if the aluminum content of the molten steel does not meet the requirement after the vacuum treatment is finished, the aluminum wire can be fed before the calcium feeding to supplement the molten steel aluminum, and the calcium can be fed 5min after the aluminum feeding is finished. After the aluminum wire is fed, the large-particle aluminum oxide impurities generated by feeding aluminum can be floated in time after 5min of calcium feeding is waited, and the calcium feeding effect is ensured.
As a further improvement of the technical scheme, in the step 2), the average temperature of the molten steel after the standing treatment is in a control range from the conventional ladle adjustment to the continuous casting end point temperature, and the temperature before the standing treatment is added according to the requirement of the average temperature of the molten steel after the treatment according to the time of standing minutes multiplied by 0.3-0.5 ℃/minute. The molten steel temperature control in the steelmaking process is implemented by a backward pushing method, namely, the pouring temperature is determined according to the superheat degree required by pouring, and the temperature in the previous process is backward pushed forward according to the temperature reduction of the process. The temperature requirement in the technical scheme is basically consistent with that of the conventional process, and the method can well control the temperature of the molten steel.
As a further improvement of this embodiment, in step 3), a magnesium covering agent is used in the impact zone where the molten steel is impacted from the ladle to the tundish, and a calcium-aluminum covering agent is used in the pouring zone where the molten steel flows from the tundish to the mold. The magnesium covering agent is adopted in the impact area, so that the covering agent slag entrapment caused by the violent flowing of molten steel in the impact area can be prevented, and the magnesium covering agent has high melting point and cannot be involved. In the pouring area, temperature measurement sampling is required, temperature measurement sampling cracks are easily left in the area by using the magnesium covering agent, and secondary oxidation Ds (chemical Ds) impurities are easily formed when molten steel is exposed to air during pouring.
Also, for the step 3) as described above, the MgO content of the induction heating path refractory is preferably controlled to not less than 90%. The induction heating channel can not avoid certain scouring to the furnace lining due to induction heating, and when the refractory material requires that the MgO content is not less than 90 percent, the refractory material can be ensured not to fall off and inclusions adhered to the inner wall of the channel can not fall off due to chemical reaction. Although the technical scheme needs a tundish electromagnetic induction heating device and the investment of continuous casting equipment is slightly increased, the cost in the steelmaking production process is basically not changed greatly compared with the conventional process.
In addition, the method for controlling Ds inclusion, namely punctiform inclusion in the steelmaking continuous casting process is mainly suitable for aluminum-containing deoxidized steel with requirements on Ds inclusion; the reason why the method is mainly applied to aluminum-containing deoxidized steel with high Ds inclusion requirement is that the aluminum-containing steel is easier to generate Ds inclusion. In the silicon deoxidized steel, the silicate inclusions are easier to generate C-type deformable inclusions, so that the application of the silicon deoxidized steel aims at controlling not Ds inclusions but C-type inclusions.
The invention can be implemented in the process of producing the high-end steel grade in the electric furnace flow or the converter flow, and the vacuum treatment equipment can be VD or RH.
The invention provides a control method of Ds inclusion, namely punctiform inclusion in the steelmaking and continuous casting process, and aims to comprehensively and stably control the Ds inclusion of molten steel, thereby improving the quality stability of Ds inclusion such as bearing steel, gear steel, cold forging steel and the like which require high steel grades. The method for controlling Ds inclusion, namely punctiform inclusion, in the steelmaking and continuous casting processes is mainly suitable for aluminum-containing deoxidized steel with requirements on Ds inclusion, achieves the Ds inclusion overall size smaller than 17 mu m, namely the Ds inclusion rating overall size smaller than 0.5 grade, achieves the control level of the Ds inclusion of electroslag steel, and fundamentally eliminates the harm brought by the Ds inclusion.
Detailed Description
The invention provides a method for controlling Ds inclusion, namely punctiform inclusion in the steelmaking continuous casting process, which is mainly suitable for aluminum-containing deoxidized steel with requirements on the Ds inclusion, and mainly comprises the following steps:
1) after the vacuum treatment in the steelmaking process is finished, feeding a small amount of calcium to adjust the calcium content of the molten steel, wherein the calcium content of the molten steel before continuous casting is required to be controlled to be 2-5 ppm;
2) standing the molten steel in the steel ladle for 50-90 min;
3) adjusting molten steel to a continuous casting station for casting, supplementing energy to the molten steel by using induction heating, and ensuring that the casting temperature is stably controlled at the superheat degree of 15-30 ℃;
4) the molten steel reaches the mold to be solidified. Finally, the molten steel is solidified into a qualified steel billet, and the total Ds inclusion of the steel billet is less than 17 mu m.
The invention can be applied to converter flow or electric furnace flow, the vacuum treatment equipment can be VD or RH, but a station is required to be added at the vacuum treatment position for placing the steel ladle, otherwise, the whole continuous casting material flow is influenced by overlong standing time.
The application of the present invention is further illustrated by the following more specific examples.
Example 1:
the embodiment is implemented on a 100-ton converter-LF-RH-CC process, the smelting steel is high-carbon chromium GCr15 bearing steel, the weight of molten steel is 100 tons, and the specific implementation process is as follows:
1) after RH vacuum treatment is finished, molten steel components are not required to be adjusted, 40m of calcium wire is fed, about 4kg of calcium wire is fed, the molten steel is slightly stirred for 3min after wire feeding, the calcium content of the molten steel is controlled to be 2ppm, and the temperature of the molten steel is 1530 ℃ after the calcium wire feeding is finished through RH process control;
2) standing molten steel in a steel ladle, adding carbonized rice hulls to a slag surface at the beginning of a standing process for heat preservation treatment, strictly keeping bottom blowing and stirring in the standing process, standing for 60min, and keeping the molten steel at 1506 ℃ after the standing is finished;
3) molten steel is adjusted to a bloom continuous casting station for casting, the tundish needs to continuously measure the temperature in the casting process, and the molten steel is supplemented with energy by induction heating to ensure that the casting temperature is stably controlled at 20 ℃ of superheat degree. During pouring, the covering agent of the tundish is used in the impact area where the molten steel impacts from the ladle to the tundish, and is used in the pouring area where the molten steel flows from the tundish to the crystallizer. The MgO content of the induction heating channel refractory is 94 percent.
4) And the molten steel reaches the crystallizer for solidification, a submerged nozzle for draining the molten steel from the tundish to the crystallizer is a double-hole nozzle, and the insertion depth of the nozzle is 160 mm.
The final molten steel solidified into a standard large steel billet (cross-sectional size 340 x 400mm) with Ds inclusions throughout less than 17 μm.
Example 2:
the embodiment is implemented on a 150-ton electric furnace-LF-VD-CC flow, the smelting steel is high-carbon chromium GCr15 bearing steel, the weight of molten steel is 150 tons, and the specific implementation process is as follows:
1) after VD vacuum treatment is finished, molten steel components are not required to be adjusted, 50m of calcium wires are fed for about 5kg, the molten steel is slightly stirred for 5min after wire feeding, the calcium content of the molten steel is controlled to be 3ppm, and the temperature of the molten steel is 1540 ℃ after the calcium wires are fed through VD process control;
2) standing molten steel in a steel ladle, adding carbonized rice hulls to a slag surface at the beginning of a standing process for heat preservation treatment, strictly keeping bottom blowing and stirring in the standing process, standing for 90min, and keeping the molten steel at 1501 ℃ after standing;
3) molten steel is adjusted to a bloom continuous casting station for casting, the tundish needs to continuously measure the temperature in the casting process, and the molten steel is supplemented with energy by induction heating to ensure that the casting temperature is stably controlled at 15 ℃. During pouring, the covering agent of the tundish is used in the impact area where the molten steel impacts from the ladle to the tundish, and is used in the pouring area where the molten steel flows from the tundish to the crystallizer. The MgO content of the induction heating channel refractory is 90 percent.
4) And the molten steel reaches the crystallizer for solidification, a submerged nozzle for draining the molten steel from the tundish to the crystallizer is a four-hole nozzle, and the insertion depth of the nozzle is 140 mm.
The final molten steel was solidified into a satisfactory large steel slab (cross-sectional size 320 x 430mm) having Ds inclusions throughout less than 15 μm.
Example 3:
the embodiment is implemented on a 120-ton electric furnace-LF-VD-CC process, the smelting steel seeds are 45K cold forging steel, the weight of molten steel is 120 tons, and the specific implementation process is as follows:
1) after VD vacuum treatment is finished, the components of the molten steel are not required to be adjusted, 50m of calcium wires are fed for about 5kg, the molten steel is slightly stirred for 5min after wire feeding, the calcium content of the molten steel is controlled to be 5ppm, and the temperature of the molten steel is 1590 ℃ after the calcium wires are fed through VD process control;
2) standing molten steel in a steel ladle, adding carbonized rice hulls to a slag surface at the beginning of a standing process for heat preservation treatment, strictly keeping bottom blowing and stirring in the standing process, standing for 70min, and keeping the molten steel at 1555 ℃ after standing is finished;
3) molten steel is adjusted to a bloom continuous casting station for casting, the tundish needs to continuously measure the temperature in the casting process, and the molten steel is supplemented with energy by induction heating to ensure that the casting temperature is stably controlled at 30 ℃. During pouring, the covering agent of the tundish is used in the impact area where the molten steel impacts from the ladle to the tundish, and is used in the pouring area where the molten steel flows from the tundish to the crystallizer. The MgO content of the induction heating channel refractory material is 92 percent.
4) And the molten steel reaches the crystallizer for solidification, a submerged nozzle for draining the molten steel from the tundish to the crystallizer is a double-hole nozzle, and the insertion depth of the nozzle is 150 mm.
The final molten steel solidified into a satisfactory large steel slab (section size 320 × 425mm) with Ds inclusions throughout less than 17 μm.
Example 4:
the implementation 1 is implemented on a 300-ton converter-LF-RH-CC process, the smelting steel type is chromium-molybdenum fine gear steel (containing 0.21 percent of carbon), the weight of molten steel is 300 tons, and the specific implementation process is as follows:
1) after RH vacuum treatment is finished, the components of molten steel are not required to be adjusted, 100m of calcium wire is fed, about 10kg of calcium wire is fed, the molten steel is slightly stirred for 5min after wire feeding, the calcium content of the molten steel is controlled to be 5ppm, and the temperature of the molten steel is 1600 ℃ after the calcium wire feeding is controlled by an RH process;
2) standing molten steel in a steel ladle, adding carbonized rice hulls to a slag surface at the beginning of a standing process for heat preservation treatment, strictly stopping bottom blowing and stirring in the standing process, standing for 80min, and keeping the molten steel temperature 1560 ℃ after standing;
3) molten steel is adjusted to a bloom continuous casting station for casting, the tundish needs to continuously measure the temperature in the casting process, and the molten steel is supplemented with energy by induction heating to ensure that the casting temperature is stably controlled at 30 ℃. During pouring, the covering agent of the tundish is used in the impact area where the molten steel impacts from the ladle to the tundish, and is used in the pouring area where the molten steel flows from the tundish to the crystallizer. The MgO content of the induction heating channel refractory is 90 percent.
4) And the molten steel reaches the crystallizer for solidification, a submerged nozzle for draining the molten steel from the tundish to the crystallizer is a double-hole nozzle, and the insertion depth of the nozzle is 170 mm.
The final molten steel was solidified into a satisfactory large steel slab (cross-sectional size 420 x 520mm) having Ds inclusions throughout less than 15 μm.
Wherein, the components listed in the invention are all in mass percentage.
Claims (10)
1. A method for controlling Ds inclusion in a steel-making casting process is characterized by comprising the following steps:
1) after the vacuum treatment in the steelmaking process is finished, finely adjusting the components of the molten steel to meet the product requirements, feeding a small amount of calcium to adjust the calcium content of the molten steel, slightly stirring the molten steel for 3-5min after calcium feeding, and controlling the calcium content of the molten steel to be 2-5ppm before continuous casting;
2) standing molten steel in a steel ladle, wherein the molten steel is subjected to heat preservation in the standing process, bottom blowing stirring is strictly forbidden in the standing process, and the standing time is 50-90 min;
3) molten steel is adjusted to a continuous casting station for casting, the tundish needs to continuously measure the temperature in the casting process, the casting temperature is stably controlled at 15-30 ℃, and the molten steel is subjected to supplementary heating when necessary;
4) the molten steel reaches the crystallizer for solidification, and the molten steel is required to be drained from the tundish to a submerged nozzle of the crystallizer, and the insertion depth of the submerged nozzle is 140-170 mm.
2. A method of controlling Ds inclusions in a steelmaking casting process as claimed in claim 1 wherein in step 1) the insulation treatment is performed by adding carbonised rice hulls to the slag surface.
3. The method for controlling Ds inclusions in a steelmaking casting process as set forth in claim 1, wherein in the step 1), the calcium feeding amount is controlled to be 0.03-0.05kg/t when the calcium content of the molten steel is adjusted.
4. A method for controlling Ds inclusions in a steelmaking casting process as claimed in claim 1, further including the step of replenishing molten steel with aluminum after the vacuum process is completed and before the calcium feeding in step 1), wherein the calcium feeding step is started 5min after the aluminum feeding is completed.
5. The method for controlling Ds inclusions in a steelmaking casting process according to claim 1, wherein in the step 2), the average temperature of the molten steel after the standing treatment is within a control range from the conventional ladle handling to the end point temperature of continuous casting, and the temperature before the standing is multiplied by 0.3-0.5 ℃/min according to the time of the standing minute plus the requirement of the average temperature of the molten steel after the treatment.
6. A method for controlling Ds inclusions in a steelmaking casting process as claimed in claim 1 wherein in step 3) the molten steel is additionally heated by induction heating.
7. The method for controlling Ds inclusions in a steelmaking casting process as set forth in claim 6, wherein the channel wall refractories of the induction heating channel for performing the induction heating have an MgO content of not less than 90%.
8. A method for controlling Ds inclusions in a steel making casting process according to claim 1, wherein in step 3) a magnesium covering agent is applied to the impact area where the molten steel is impacted from the ladle to the tundish and a calcium aluminum covering agent is applied to the pouring area where the molten steel flows from the tundish to the mold.
9. A method for controlling Ds inclusions in a steelmaking casting process as claimed in claim 1 wherein in step 4) said submerged entry nozzle is a two-or four-hole nozzle.
10. Use of a control method according to any one of claims 1-9 for controlling Ds inclusions in an aluminium-containing deoxidized steel.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103451349A (en) * | 2013-08-16 | 2013-12-18 | 河北钢铁股份有限公司邯郸分公司 | Control method for preventing nozzle clogging in casting process of ultra-low carbon-aluminium deoxidized molten steel |
| CN105463150A (en) * | 2015-12-18 | 2016-04-06 | 中天钢铁集团有限公司 | Steel smelting process used for automobile hub bearing |
| CN105648344A (en) * | 2014-11-14 | 2016-06-08 | 北大方正集团有限公司 | Smelting technique and production method of bearing steel and bearing steel |
| CN110616294A (en) * | 2019-10-30 | 2019-12-27 | 广东韶钢松山股份有限公司 | Sulfur-containing aluminum-containing steel, smelting method and application thereof |
-
2020
- 2020-05-06 CN CN202010372773.8A patent/CN113621758A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103451349A (en) * | 2013-08-16 | 2013-12-18 | 河北钢铁股份有限公司邯郸分公司 | Control method for preventing nozzle clogging in casting process of ultra-low carbon-aluminium deoxidized molten steel |
| CN105648344A (en) * | 2014-11-14 | 2016-06-08 | 北大方正集团有限公司 | Smelting technique and production method of bearing steel and bearing steel |
| CN105463150A (en) * | 2015-12-18 | 2016-04-06 | 中天钢铁集团有限公司 | Steel smelting process used for automobile hub bearing |
| CN110616294A (en) * | 2019-10-30 | 2019-12-27 | 广东韶钢松山股份有限公司 | Sulfur-containing aluminum-containing steel, smelting method and application thereof |
Non-Patent Citations (3)
| Title |
|---|
| 包燕平等, vol. 1, 冶金工业出版社, pages: 182 - 187 * |
| 包燕平等, 冶金工业出版社 * |
| 肖卫军等: "铝钢生产的连铸工艺控制", 《钢铁研究》, vol. 34, no. 03, 30 June 2006 (2006-06-30), pages 43 - 45 * |
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