CN115141904B - Continuous casting blank for preparing low-carbon cold-rolled substrate and smelting process thereof - Google Patents
Continuous casting blank for preparing low-carbon cold-rolled substrate and smelting process thereof Download PDFInfo
- Publication number
- CN115141904B CN115141904B CN202210793670.8A CN202210793670A CN115141904B CN 115141904 B CN115141904 B CN 115141904B CN 202210793670 A CN202210793670 A CN 202210793670A CN 115141904 B CN115141904 B CN 115141904B
- Authority
- CN
- China
- Prior art keywords
- converter
- molten steel
- tapping
- slag
- equal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
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
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/02—Dephosphorising or desulfurising
-
- 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
- B22D11/001—Continuous casting of metals, i.e. casting in indefinite lengths of specific alloys
-
- 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
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The application discloses a smelting process for preparing a continuous casting blank of a low-carbon cold-rolled substrate, which comprises the following steps of: KR stirring desulfurization is carried out on the blast furnace molten iron; smelting the desulphurized molten iron in a converter to obtain molten steel in the converter; carrying out RH refining treatment on the converter molten steel to obtain refined molten steel; finally, continuously pouring the obtained refined molten steel to obtain the continuous casting billet; wherein aluminum is added in the tapping process of converter smelting, and the addition amount of the aluminum is (a) the free oxygen at the end point of the converter-b) kg/t, wherein a is more than or equal to 11 and less than or equal to 12,0.3 and b is more than or equal to 0.4. The application also discloses a continuous casting blank obtained by the smelting process. According to the application, a specific proportion of aluminum is added in the converter tapping process to deoxidize and heat, so that the problems of large temperature drop, high free oxygen content of molten steel from RH to a station, secondary oxidation of molten steel to slag and the like in the converter tapping process are solved; the continuous casting billet inclusion obtained by the application has small size and low total oxygen content, and is convenient for preparing high-quality low-carbon cold-rolled substrates.
Description
Technical Field
The application relates to the field of cold-rolled substrate preparation, in particular to a continuous casting blank for preparing a low-carbon cold-rolled substrate and a smelting process thereof.
Background
The low-carbon cold-rolled substrate is mainly used as a raw material of a cold-rolled sheet, is widely applied to industries such as automobiles, household appliances, food packaging, buildings and the like, and has high requirements on surface quality. Common defects of the low-carbon cold-rolled substrate comprise slag inclusion, skin tilting, sand holes, holes and the like, and the defects are mainly caused by large-size nonmetallic inclusion generated in the steelmaking process. Therefore, the size and the number of nonmetallic inclusions are important points of the steelmaking process control of the low-carbon cold-rolled substrate.
The smelting is used as an important step for preparing the low-carbon cold-rolled substrate, and the process flow comprises KR desulfurization, converter smelting, RH refining (vacuum circulation degassing refining method) and continuous casting. However, the existing technology mainly has the following problems: 1) The tapping temperature of the converter is high, the smelting difficulty is high, and the refractory loss is serious; 2) The steel tapping temperature of the converter is greatly reduced, the RH arrival temperature is lower, oxygen blowing and aluminum adding are carried out in the RH process, and the temperature is increased, so that the cleanliness of molten steel is affected; 3) RH to station slag has high oxidizing property, poor slag fluidity and poor inclusion adsorption capability; 4) When RH arrives at a station, the free oxygen content of molten steel is high, so that the free oxygen in the molten steel is transferred to slag, the oxidability of the slag is increased, and the slag modifying effect is restricted; 5) Secondary slag modification is carried out in the RH process, so that dust pollution is serious, and the modification effect is poor.
Chinese patent document CN105671238A discloses a modification method of cold-rolled sheet steel slag, wherein the steel slag is deoxidized by an Al-based modifier after converter tapping is finished, and the steel slag is secondarily deoxidized by adding the Al-based modifier again after RH refining is finished, so that the problem of strong oxidizing property of the steel slag in the prior art is solved, the number of nonmetallic inclusions in the steel is reduced, and the surface quality of the cold-rolled sheet is improved. However, the problems of high converter end temperature and large molten steel temperature drop in the tapping process are not solved, and the method requires two slag modifications after the converter and the RH refining are finished, and has the advantages of complex process, high operation difficulty and poor inclusion size and quantity control stability.
Disclosure of Invention
The application aims to solve the technical problems of large number of defects and finally obtained low-carbon cold-rolled substrate inclusions and large size in the smelting process of the existing low-carbon cold-rolled substrate, thereby providing a continuous casting blank for preparing the low-carbon cold-rolled substrate and the smelting process thereof.
Therefore, the application adopts the following technical scheme:
the application provides a smelting process for preparing a continuous casting blank of a low-carbon cold-rolled substrate, which comprises the following steps of:
s1: KR stirring desulfurization is carried out on the blast furnace molten iron;
s2: smelting the desulphurized molten iron in a converter to obtain molten steel in the converter;
s3: RH refining treatment is carried out on the converter molten steel to obtain refined molten steel;
s4: continuously pouring the obtained refined molten steel to obtain the continuous casting billet;
in the step S2, aluminum is added in the tapping process of converter smelting, wherein the addition amount of the aluminum is (a) the free oxygen at the end point of the converter-b) kg/t, and a is more than or equal to 11 and less than or equal to 12,0.3 and b is more than or equal to 0.4.
Further, the free oxygen at the end point of the converter is 0.05 to 0.08 weight percent.
In the step S2, when the tapping amount of the converter reaches 11.1-16.7wt% of the ladle loading amount, lime 1-3kg/t is added into the ladle, and a slag modifier is added after the tapping of the converter, wherein the adding amount of the slag modifier is (c is equal to or less than or equal to 50 and equal to 0.5 is equal to or less than or equal to 0.8, preferably, a=11.2, b=0.338, c=45.2 and d=0.624, and the adding amount of the slag modifier is (c is equal to or less than or equal to 50 and equal to 0.5 is equal to or less than or equal to d).
Further, the slag modifier comprises 15 to 25 weight percent of CaO and 10 to 20 weight percent of Al 2 O 3 25 to 30 weight percent of Al and 5 to 10 weight percent of SiO 2 And 15 to 20wt% CaF 2 。
Further, in the step S2, the converter end temperature is 1640-1660 ℃, the converter end carbon content is 0.03-0.05wt%, the T.Fe in the converter end slag is 15-18wt%, and the slag discharging amount of the converter tapping is 2-4kg/t.
In the step S2, the ladle bottom blowing is started 2-3min before tapping of the converter, the bottom blowing strength is 2.5-3.5NL/min/t, the bottom blowing strength in the tapping process is 1.5-2.5NL/min/t, and the bottom blowing strength after tapping is 0.5-1.0NL/min/t.
In the step S3, in RH refining treatment, decarburization time is 5-7min, and circulation time is 5-8min after auxiliary materials are added for alloying;
the decarburization is natural decarburization, and oxygen blowing is not performed in the decarburization process;
the auxiliary materials comprise aluminum particles, manganese alloy, carbon powder and the like according to the product requirement.
Through controlling the smelting end point of a converter, semi-calving design in the tapping process, slag modification process after tapping and the like, the composition T.Fe of the RH arrival ladle slag is 5-8wt%, the RH arrival temperature is 1610-1630deg.C, and the arrival free oxygen is 0.025-0.035wt%;
after RH natural decarburization, the free oxygen content is 0.008-0.015wt%;
when RH breaks the air, the ladle slag component T.Fe is less than or equal to 5wt%;
between the step S3 and the step S4, the time difference between RH breaking and pouring is 10-15min;
in the step S4, the argon flow of the stopper rod is 8-12L/min during continuous casting.
The empty ladle time of the ladle for bearing molten steel in the smelting process is less than or equal to 60 minutes.
The application also provides a continuous casting blank for preparing the low-carbon cold-rolled substrate, which is prepared by the smelting process, wherein the carbon content of the continuous casting blank is 0.02-0.07wt%, the size of inclusions is less than or equal to 15 mu m, and the total oxygen content is less than or equal to 15ppm.
The technical scheme of the application has the following advantages:
(1) According to the application, a specific proportion of aluminum is added in any time period from the beginning to the end of converter tapping to perform deoxidation and heating, the free oxygen content of RH to station molten steel is controlled, the transfer of free oxygen in molten steel to slag is inhibited, and the problems of large temperature drop, high free oxygen content of RH to station molten steel, secondary oxidation of molten steel to slag and the like in the converter tapping process are solved.
(2) According to the application, lime is added in the converter tapping process, and a slag modifier is added after tapping is finished, so that the chemical composition of slag is adjusted, the oxidizing property of slag is reduced, and meanwhile, free oxygen in molten steel is inhibited from being transferred to slag through RH to station slag oxidizing property control, so that the oxidizing property of slag is further reduced.
(3) According to the application, through the design of charging in the tapping process of the converter, the design of ladle bottom blowing flow in the tapping process, continuous casting argon seal optimization, ladle state management and the like, the following technical effects are achieved: the RH to-station temperature is increased, and the requirement of the converter end temperature is reduced; reducing the free oxygen content of RH to-station, and weakening the free oxygen mass transfer of molten steel to slag; reducing the oxidizing property of RH to-station slag, and canceling the modification of slag at the 2 nd time after RH tapping; the free oxygen content before alloying is reduced, the quantity of endogenous inclusions is reduced, and the purity of the steel is improved.
(4) The smelting process solves the problem of large temperature drop in the tapping process of the converter, improves the RH arrival temperature, and creates proper conditions for RH treatment; the low FeO activity, the high CaO activity and the low Al are obtained by optimizing the slagging process 2 O 3 The low-melting-point slag system with activity improves the fluidity of slag and the capability of absorbing impurities, and simultaneously reduces the secondary oxidation of slag to molten steel; the free oxygen content of the molten steel suitable for RH to-be-treated is controlled, so that the transfer of free oxygen in the molten steel to slag is inhibited, and the oxidizing property of the slag from RH to the station is reduced.
(5) The continuous casting billet inclusion obtained by the application has small size and low total oxygen content, and is convenient for preparing high-quality low-carbon cold-rolled substrates.
Detailed Description
The following examples are provided for a better understanding of the present application and are not limited to the preferred embodiments described herein, but are not intended to limit the scope of the application, any product which is the same or similar to the present application, whether in light of the present teachings or in combination with other prior art features, falls within the scope of the present application.
The specific experimental procedures or conditions are not noted in the examples and may be followed by the operations or conditions of conventional experimental procedures described in the literature in this field. The reagents or apparatus used were conventional reagent products commercially available without the manufacturer's knowledge.
Example 1
The embodiment provides a continuous casting blank for preparing a low-carbon cold-rolled substrate, wherein the steel grade is DC01, the carbon content is 0.02-0.04wt%, the specific smelting process is as follows, and the ladle loading amount is 180t:
(1) KR desulfurization is carried out on the blast furnace molten iron;
(2) The desulfurized molten ironAnd smelting in a converter to obtain molten steel of the converter, wherein the final temperature of the converter is 1645-1658 ℃, the final carbon content of the converter is 0.031-0.049wt%, and the final slag of the converter is T.Fe15.2-17.9wt%. Adding aluminum blocks in the tapping process, wherein the adding amount is (11.2 x converter endpoint free oxygen-0.338) kg/t, adding lime 1-3kg/t into a ladle when the tapping amount of the converter reaches 20-30 t, adding a slag modifier after tapping, wherein the adding amount of the modifier is (45.2 x converter endpoint free oxygen-0.624) kg/t, and the tapping slag amount of the converter is 2-4kg/t. Wherein the slag modifier comprises 19.7-25.3wt% CaO, 15.8-17.3wt% Al 2 O 3 25.2 to 28.8 weight percent of Al and 7.2 to 9.5 weight percent of SiO 2 And 18.1 to 19.9wt% CaF 2 The other is impurity. 2-3min before tapping of the converter, opening ladle bottom blowing, wherein the bottom blowing flow is 479-620NL/min, the bottom blowing flow is 297-441NL/min in the tapping process, and the bottom blowing flow is 101-177NL/min after tapping is finished.
The concrete converter end point conditions, tapping and charging and tapping process bottom blowing control parameters are shown in table 1;
TABLE 1 converter endpoint conditions, tapping feed, tapping process bottom blowing control parameters
(3) RH refining treatment is carried out on the converter molten steel, the weight percentage of RH to-station ladle slag components T.Fe5.2-7.7, the temperature of RH to-station is 1611-1627 ℃, the free oxygen to-station is 0.0287-0.0341wt%, oxygen blowing is forbidden in the RH decarburization process, natural decarburization is carried out for 5-7min, the free oxygen content of molten steel is 0.0097-0.0133wt%, aluminum particles, metal manganese, carbon powder and the like are respectively added in sequence according to the component requirements of a finished product, and RH emptying tapping is carried out after alloying and circulation is carried out for 5-8min, so that refined molten steel is obtained.
The specific RH arrival parameters and other process control parameters are shown in Table 2:
table 2 RH arrival parameters and other process control parameters
(4) Continuously pouring the obtained refined molten steel, wherein the time between RH breaking and continuous casting pouring is 12-15min, the argon flow of a continuous casting stopper rod is 9-10L/min, and the ladle blank time for bearing the molten steel is less than or equal to 60min, so as to obtain the continuous casting blank.
The specific continuous casting parameters, ladle states and finished product quality are shown in Table 3.
TABLE 3 continuous casting parameters, ladle status and finished product quality
Example 2
The embodiment provides a continuous casting blank for preparing a low-carbon cold-rolled substrate, wherein the steel grade is T-4, the carbon content is 0.04-0.07wt%, the specific smelting process is as follows, and the ladle loading amount is 180T:
(1) KR desulfurization is carried out on the blast furnace molten iron;
(2) Smelting the desulfurized molten iron in a converter to obtain molten steel of the converter, wherein the converter blowing end temperature is 1646-1660 ℃, the converter end carbon content is 0.032-0.046wt% and the converter end slag is T.Fe15.2-17.9wt%. Adding aluminum blocks in the tapping process, wherein the adding amount is (11.2 x converter endpoint free oxygen-0.338) kg/t, adding lime 1-3kg/t into a ladle when the tapping amount of the converter reaches 20-30 t, adding a slag modifier after tapping, wherein the adding amount of the modifier is (45.2 x converter endpoint free oxygen-0.624) kg/t, and the tapping slag amount of the converter is 2-4kg/t. The slag modifier consists of CaO in 20.3-24.5 wt% and Al in 17.2-19.7 wt% 2 O 3 28.8 to 29.7 weight percent of Al and 9.1 to 9.9 weight percent of SiO 2 And 18.7 to 19.8wt% CaF 2 The others are impurities.
2-3min before tapping of the converter, opening ladle bottom blowing, wherein the bottom blowing flow is 468-600NL/min, the bottom blowing flow is 321-432NL/min in the tapping process, and the bottom blowing strength is 98-176NL/min/t after tapping is finished.
The concrete converter end point conditions, tapping and charging and tapping process bottom blowing control parameters are shown in table 4;
TABLE 4 converter endpoint conditions, tapping feed, tapping process bottom blowing control parameters
(3) RH refining treatment is carried out on the converter molten steel, the RH arrival ladle slag component T.Fe5.6-7.5wt%, the RH arrival temperature is 1614-1629 ℃, the arrival free oxygen is 0.0266-0.0342wt%, the RH decarburization is carried out for 5-7min, the free oxygen content of molten steel is 0.095-0.014wt%, aluminum particles, metal manganese, carbon powder and the like are respectively added in sequence, after alloying, the RH blank breaking tapping and the RH blank breaking tapping are carried out after 5-8min of circulation, and refined molten steel is obtained.
The specific RH arrival parameters and other process control parameters are shown in Table 5:
TABLE 5 RH arrival parameters and other process control parameters
(4) Continuously pouring the obtained refined molten steel, wherein the time between RH void breaking and continuous casting is 11-13min, the argon flow of a continuous casting stopper rod is 8-11NL/min, and the ladle void time for bearing the molten steel is less than or equal to 60min.
The specific continuous casting parameters, ladle states and finished product quality are shown in Table 3.
TABLE 6 continuous casting parameters, ladle status and finished product quality
Comparative example 1
The comparative example provides a continuous casting blank for preparing a low-carbon cold-rolled substrate, wherein the steel grade is DC01, the carbon content is 0.02-0.04wt%, the specific smelting process is as follows, and the ladle loading amount is 180t:
the process flow is KR desulfurization-converter smeltingrefining-RH treatment-continuous casting. The end point temperature of converter blowing is above 1680 ℃, the end point carbon content of the converter is 0.03-0.07wt%, and the end slag T.Fe of the converter is above 18 wt%. When the tapping amount of the converter reaches 20-30 t, lime 3-4kg/t is added into the ladle, after tapping is finished, slag modifier 2-4kg/t steel is added, and the tapping amount of the converter is less than or equal to 3kg/t. Wherein the slag modifier comprises 19.7-25.3wt% CaO, 15.8-17.3wt% Al 2 O 3 25.2 to 28.8 weight percent of Al and 7.2 to 9.5 weight percent of SiO 2 And 18.1 to 19.9wt% CaF 2 The other is impurity. The high temperature is required for the end point of the converter, so that the oxidizing property of the final slag of the converter is high, and the content of the slag component T.Fe of the steel ladle from RH to the station is more than 10wt%. Aluminum blocks are not added in the tapping process of the converter, the tapping temperature is reduced greatly, the RH arrival temperature is less than or equal to 1600 ℃, the arrival temperature is low, oxygen blowing and aluminum adding are needed in the RH decarburization process, and the temperature is increased, so that the number of inclusions in molten steel is large. Meanwhile, in order to meet decarburization requirements, RH is 0.045-0.065wt% of free oxygen to the station, and oxygen content in molten steel is transferred to slag to influence the modifying effect of the slag. After RH decarburization for 5-7min, the free oxygen content of molten steel is 0.030-0.045wt%, aluminum particles, manganese metal, carbon powder and the like are respectively added in sequence, and after alloying and circulation for 5-10min, RH void breaking tapping is carried out. RH to station ladle furnace slag component T.Fe 8-10wt%. The time between RH void breaking and continuous casting is 11-13min, the argon flow of a continuous casting stopper rod is 5-11NL/min, and the ladle void time for bearing molten steel is less than or equal to 60min. The size of the inclusions in the final product is mainly distributed between 25 and 35 mu m, and the total oxygen is 20 to 30ppm.
Comparative example 2
This comparative example provides a continuous casting slab for preparing a low carbon cold rolled substrate, the steel grade being DC01, the carbon content being 0.02-0.04wt%, wherein the ladle loading is 180t, and the difference from example 1 is that the addition of aluminum is improved, and the specific smelting process is as follows:
the process flow comprises KR desulfurization, converter smelting, RH treatment and continuous casting. The final temperature of converter blowing is 1658 ℃, the final carbon content of the converter is 0.035wt%, and the final slag of the converter is 17.2wt%. When the tapping amount of the converter reaches 20-30 t, 412kg of lime is added into the ladle, 200kg of aluminum blocks are added in the tapping process, 447kg of slag modifier is added after tapping is finished, and the tapping amount of the converter is 400kg. Wherein the slag isThe modifier consists of CaO 19.7-25.3 wt% and Al 15.8-17.3 wt% 2 O 3 25.2 to 28.8 weight percent of Al and 7.2 to 9.5 weight percent of SiO 2 And 18.1 to 19.9wt% CaF 2 The other is impurity. Because excessive aluminum blocks are added in the tapping process of the converter, the free oxygen content of RH arrival molten steel is 0.0078wt%, the content of RH arrival ladle slag is T.Fe 6wt%, and the RH arrival temperature is 1632 ℃. Because the RH arrival temperature is high, a certain amount of cooling scrap steel needs to be added in the later stage, the cleanliness of molten steel is deteriorated, and the smelting cost is increased. Because the free oxygen content of RH to the station is low, the RH treatment early decarburization needs to be difficult to meet, and oxygen blowing decarburization is needed, so that after RH decarburization is performed for 7min, the free oxygen content of molten steel is 0.0356wt%, aluminum particles, manganese metal, carbon powder and the like are respectively added in sequence, after alloying, circulation is performed for 5-10min, and RH blank breaking tapping is performed. Because of oxygen blowing decarburization in the RH decarburization stage, secondary oxidization is carried out on slag, the RH breaks the ladle component T.Fe 8.3wt%, the slag has strong oxidizing property, secondary oxidization is carried out on molten steel in the later stage, and the cleanliness of molten steel is deteriorated. The time between RH void breaking and continuous casting is 12min, the argon flow of a continuous casting stopper rod is 9NL/min, and the ladle void time for bearing molten steel is 55min.
The size of the inclusions in the final product is mainly distributed between 30 and 50 mu m, and the total oxygen is 25 to 40ppm.
Comparative example 3
This comparative example provides a continuous casting slab for preparing a low carbon cold rolled substrate, the steel grade being DC01, the carbon content being 0.02-0.04wt%, wherein the ladle loading is 180t, and the difference from example 1 is that part of parameters in the smelting process are changed, and the specific smelting process is as follows:
the process flow comprises KR desulfurization, converter smelting, RH treatment and continuous casting. The converter blowing endpoint temperature is 1647 ℃, the converter endpoint carbon content is 0.049wt%, the endpoint oxygen content is 0.0876wt%, and the converter endpoint slag is T.Fe22.3wt%. When the tapping amount of the converter reaches 20-30 t, 421kg of lime is added into the ladle, 75kg of aluminum blocks are added in the tapping process, 400kg/t of slag modifier is added after tapping, and the tapping amount of the converter is 400kg. Wherein the slag modifier comprises 19.7-25.3wt% CaO, 15.8-17.3wt% Al 2 O 3 25.2 to 28.8 weight percent of Al and 7.2 to 9.5 weight percent of SiO 2 And 18.1 to 19.9wt% CaF 2 The other is impurity.
The content of the T.Fe in the end slag of converter blowing is high, the content of the T.Fe in the RH to-station slag is high and reaches 12.3 weight percent, the content of the free oxygen in the end point of the converter is high and the content of the free oxygen in the RH to-station slag is high and reaches 0.0555 weight percent, and the free oxygen in molten steel diffuses into the slag and influences the modifying effect of the RH to-station slag. RH to station temperature 1628 ℃. Because the free oxygen content of RH to the station is high, after RH decarburization is carried out for 7min, the free oxygen content of molten steel is high and reaches 0.0388wt percent, and the quantity of inclusions generated by subsequent deoxidization alloying is large. Aluminum particles, manganese metal, carbon powder and the like are respectively added in sequence, and after alloying and circulation is carried out for 5-10min, RH emptying tapping is carried out. Because RH to the station slag has high oxidizing property, RH breaks the ladle composition T.Fe 9.3wt% when empty, the slag has strong oxidizing property, can oxidize molten steel secondarily in the later stage, and worsens the cleanliness of molten steel.
The time between RH void breaking and continuous casting is 13min, the argon flow of a continuous casting stopper rod is 9NL/min, and the ladle void time for bearing molten steel is 42min. Although partial design can solve partial problems, the size of the inclusions in the final finished product is mainly distributed between 30 and 50 mu m, and the total oxygen is 25 to 40ppm because of poor slag modifying effect and more inclusions generated by deoxidation.
Test example 1
The continuous casting billet with the furnace number of A1 in the example 1 is used for preparing a low-carbon cold-rolled substrate, and the specific preparation process is as follows:
the qualified casting blank with the furnace number of A1 in the example 1 is conveyed into a heating furnace through a conveying roller to be heated to 900-1200 ℃, is conveyed out of the heating furnace and is descaled by high-pressure water, and rough rolling is carried out after oxide skin on the surface of the casting blank is removed. After the rough rolled strip steel is subjected to secondary descaling by high-pressure water, rolling in a finishing mill, then carrying out laminar cooling, coiling by a coiling machine, bundling by a bundling machine, weighing and labeling to obtain a qualified hot rolled steel coil, namely a cold rolled substrate.
The obtained low-carbon cold-rolled substrate has no defects such as surface scab, skin warping, sand holes, holes and the like, and the tensile strength and the impact performance of the low-carbon cold-rolled substrate meet the national standard requirements after performance test is carried out on the low-carbon cold-rolled substrate.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the application.
Claims (7)
1. A smelting process for preparing a continuous casting blank of a low-carbon cold-rolled substrate, which is characterized by comprising the following steps of:
s1: KR stirring desulfurization is carried out on the blast furnace molten iron;
s2: smelting the desulphurized molten iron in a converter to obtain molten steel in the converter;
s3: RH refining treatment is carried out on the converter molten steel to obtain refined molten steel;
s4: continuously pouring the obtained refined molten steel to obtain the continuous casting billet;
in the step S2, aluminum is added in the tapping process of converter smelting, wherein the addition amount of the aluminum is (a multiplied by the free oxygen at the end point of the converter-b) kg/t, and a is more than or equal to 11 and less than or equal to 12,0.3 and b is more than or equal to 0.4;
the free oxygen at the end point of the converter is 0.05-0.08wt%;
in the step S2, when the tapping amount of the converter reaches 11.1-16.7wt% of the ladle loading amount, lime is added into the ladle by 1-3kg/t, and after the tapping of the converter is finished, a slag modifier is added, wherein the adding amount of the slag modifier is (c multiplied by the free oxygen at the end point of the converter-d) kg/t, c is more than or equal to 40 and less than or equal to 50, and d is more than or equal to 0.5 and less than or equal to 0.8.
2. The smelting process of claim 1 wherein a = 11.2, b = 0.338, c = 45.2, and d = 0.624.
3. The smelting process according to claim 1 or 2, wherein the slag modifier comprises 15 to 25wt% CaO,10 to 20wt% Al 2 O 3 25-30wt% of Al and 5-10wt% of SiO 2 And 15 to 20wt% CaF 2 。
4. A smelting process according to claim 3, wherein in step S2, the converter end point temperature is 1640-1660 ℃, the converter end point carbon content is 0.03-0.05wt%, t.fe in the converter end slag is 15-18wt%, and the converter tapping slag amount is 2-4kg/t.
5. The smelting process according to claim 4, wherein in the step S2, the ladle bottom blowing is started 2 to 3min before tapping of the converter, the bottom blowing strength is 2.5 to 3.5NL/min/t, the bottom blowing strength is 1.5 to 2.5NL/min/t during tapping, and the bottom blowing strength is 0.5 to 1.0NL/min/t after tapping is finished.
6. The smelting process according to claim 5, wherein in the step S3, in the RH refining treatment, the decarburization time is 5 to 7min, and the cycle time after alloying with the auxiliary material is 5 to 8min;
the decarburization is natural decarburization, and oxygen blowing is not performed in the decarburization process;
between the step S3 and the step S4, the time difference between RH breaking and pouring is 10-15min;
in the step S4, the argon flow of the stopper rod is 8-12L/min during continuous casting.
7. The smelting process according to claim 6, wherein the empty ladle time for carrying molten steel in the smelting process is less than or equal to 60 minutes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210793670.8A CN115141904B (en) | 2022-07-05 | 2022-07-05 | Continuous casting blank for preparing low-carbon cold-rolled substrate and smelting process thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210793670.8A CN115141904B (en) | 2022-07-05 | 2022-07-05 | Continuous casting blank for preparing low-carbon cold-rolled substrate and smelting process thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115141904A CN115141904A (en) | 2022-10-04 |
| CN115141904B true CN115141904B (en) | 2023-09-22 |
Family
ID=83411249
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210793670.8A Active CN115141904B (en) | 2022-07-05 | 2022-07-05 | Continuous casting blank for preparing low-carbon cold-rolled substrate and smelting process thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115141904B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117987621B (en) * | 2024-04-07 | 2024-06-07 | 江苏省沙钢钢铁研究院有限公司 | RH single-linkage medium plate smelting method |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102719593A (en) * | 2011-03-29 | 2012-10-10 | 鞍钢股份有限公司 | Method for smelting ultra-low carbon steel |
| 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 |
| CN103937926A (en) * | 2014-03-26 | 2014-07-23 | 江苏省沙钢钢铁研究院有限公司 | Production method for ultralow-oxygen-content molten steel of ultralow-low-carbon steel |
| CN104630418A (en) * | 2015-01-15 | 2015-05-20 | 南京钢铁股份有限公司 | High-cleanliness pipeline steel smelting process |
| DE102015113412A1 (en) * | 2014-09-02 | 2016-03-03 | Nanjing Iron And Steel Corp., Ltd. | Melting process for low carbon ultra-low sulfur steel |
| CN105821178A (en) * | 2016-03-24 | 2016-08-03 | 首钢总公司 | Smelting method for ultra-low carbon steel |
| CN106011377A (en) * | 2015-10-20 | 2016-10-12 | 南京钢铁股份有限公司 | Control technology for B-class inclusions of low-carbon low-sulfur pipeline steel |
| CN109082496A (en) * | 2018-08-09 | 2018-12-25 | 山东钢铁股份有限公司 | A kind of method of whole process hypoxemia position smelting suprelow carbon steel |
-
2022
- 2022-07-05 CN CN202210793670.8A patent/CN115141904B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102719593A (en) * | 2011-03-29 | 2012-10-10 | 鞍钢股份有限公司 | Method for smelting ultra-low carbon steel |
| 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 |
| CN103937926A (en) * | 2014-03-26 | 2014-07-23 | 江苏省沙钢钢铁研究院有限公司 | Production method for ultralow-oxygen-content molten steel of ultralow-low-carbon steel |
| DE102015113412A1 (en) * | 2014-09-02 | 2016-03-03 | Nanjing Iron And Steel Corp., Ltd. | Melting process for low carbon ultra-low sulfur steel |
| CN104630418A (en) * | 2015-01-15 | 2015-05-20 | 南京钢铁股份有限公司 | High-cleanliness pipeline steel smelting process |
| CN106011377A (en) * | 2015-10-20 | 2016-10-12 | 南京钢铁股份有限公司 | Control technology for B-class inclusions of low-carbon low-sulfur pipeline steel |
| CN105821178A (en) * | 2016-03-24 | 2016-08-03 | 首钢总公司 | Smelting method for ultra-low carbon steel |
| CN109082496A (en) * | 2018-08-09 | 2018-12-25 | 山东钢铁股份有限公司 | A kind of method of whole process hypoxemia position smelting suprelow carbon steel |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115141904A (en) | 2022-10-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108330245B (en) | High-purity smelting method for stainless steel | |
| CN112342333A (en) | High-efficiency low-oxygen-level ultra-low-carbon steel production method | |
| CN109252010B (en) | Smelting method for controlling oxidability of IF steel top slag | |
| CN107354269A (en) | The method that RH complex deoxidizations produce ultra-low-carbon steel | |
| CN107365949A (en) | A kind of method of smelting ultralow-carbon high-alloy stainless steel | |
| CN114606357A (en) | Method for removing phosphorus and leaving carbon in medium-high carbon steel by converter | |
| CN112442631B (en) | Control method for titanium-containing ultra-low carbon steel cold-rolled steel defects | |
| CN111020099B (en) | Process for continuously casting straight-up medium-thin sheet billet of steel converter for low-carbon cold-rolled base material | |
| CN115141904B (en) | Continuous casting blank for preparing low-carbon cold-rolled substrate and smelting process thereof | |
| CN111500919A (en) | Production method of high-cleanliness high-titanium low-carbon steel | |
| CN112981032B (en) | Method for smelting low-titanium high-carbon chromium bearing steel by high-titanium molten iron | |
| CN113025781B (en) | Method for producing low-carbon low-silicon ultralow-sulfur steel by adopting LF (ladle furnace) single-link process | |
| CN114214481A (en) | Method for reducing nitrogen content in steel | |
| CN107502704B (en) | Method for reducing alumina inclusions in semisteel steelmaking casting blank | |
| CN111455131B (en) | Smelting and continuous casting method of high-cleanliness wear-resistant steel | |
| CN113699303A (en) | Smelting method for steel for automobile suspension spring | |
| CN115261564B (en) | Pure iron as non-aluminum deoxidizing material for amorphous soft magnetic thin belt and preparation method thereof | |
| CN115558834A (en) | Medium plate steel grade and smelting method thereof | |
| CN115537504A (en) | Preparation method of titanium-containing ultra-low carbon steel | |
| CN114150101A (en) | Method for producing electroplated tin substrate steel by using ladle casting residual molten steel | |
| CN115747407B (en) | Smelting method of low-silicon aluminum killed low-carbon steel with controllable inclusions | |
| CN114959183B (en) | Refining slag system based on aluminum deoxidized Cr5 supporting roller steel and application process thereof | |
| CN114134284B (en) | Hot continuous rolling strip steel inclusion control method and hot continuous rolling strip steel | |
| CN115747621B (en) | Ultralow titanium smelting method for high-aluminum or high-silicon electrical steel | |
| CN115927948B (en) | Smelting method of sheet continuous casting and rolling weather-resistant steel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |