CN110016533B - Production process of steel substrate for high-quality filter - Google Patents

Production process of steel substrate for high-quality filter Download PDF

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CN110016533B
CN110016533B CN201910191315.1A CN201910191315A CN110016533B CN 110016533 B CN110016533 B CN 110016533B CN 201910191315 A CN201910191315 A CN 201910191315A CN 110016533 B CN110016533 B CN 110016533B
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steel
percent
temperature
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CN110016533A (en
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马德刚
李经哲
李波
王耐
路博勋
尹宽
王建兴
杨杰
田俊强
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Tangshan Steel Group High Strength Automobile Plate Co ltd
Tangshan Iron and Steel Group Co Ltd
HBIS Co Ltd Tangshan Branch
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Tangshan Steel Group High Strength Automobile Plate Co ltd
Tangshan Iron and Steel Group Co Ltd
HBIS Co Ltd Tangshan Branch
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16—Controlling or regulating processes or operations
    • 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
    • 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
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/06—Deoxidising, e.g. killing
    • 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
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/064—Dephosphorising; Desulfurising
    • 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
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/068—Decarburising
    • 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
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Treatment Of Steel In Its Molten State (AREA)

Abstract

The invention discloses a production process of a steel substrate for a high-quality filter, which comprises the working procedures of molten iron desulphurization, converter smelting, RH treatment, medium plate blank continuous casting, plate blank heating and hot rolling; the molten iron desulphurization process comprises the following steps: desulfurizing the molten iron until S is less than or equal to 0.005 percent; in the converter smelting process, the final slag alkalinity is 3.5-4.5, 0.020-0.045% of C, less than or equal to 0.010% of S and less than or equal to 0.010% of P in the steel liquid are tapped, the end point temperature is not less than 1690 ℃, the end point oxygen level is controlled at 500-900 ppm, the steel liquid sample is not taken after the converter draws carbon, steel is directly tapped after bottom blowing and strong stirring, and the tapping time is not less than 3 minutes; the RH treatment process adopts a deep decarburization mode, the decarburization time is more than or equal to 14min, and the RH oxygen blowing amount is controlled to be less than or equal to 100m3And the vacuum circulation time is more than or equal to 8min after the alloy is added. The production process is stable in control, and can effectively control the total oxygen and nitrogen contents of the molten steel; the hot rolling surface defects are reduced, and the class B inclusions of the hot rolling substrate inclusion grade are controlled to be below 1.5 grade of fineness.

Description

Production process of steel substrate for high-quality filter
Technical Field
The invention belongs to the technical field of ferrous metallurgy processes, and particularly relates to a production process of a steel substrate for a high-quality filter.
Background
The steel for the automobile filter is subjected to deep drawing processing by adopting a steel raw material for cold rolling deep drawing, the thinnest position can reach below 0.4mm, and the inclusion of steel types has overlarge size and excessive quantity, so that the sand hole defect is easily caused in the drawing and thinning process, and the control of the inclusion of the steel types is strict. The steel for the filter at present mainly adopts ultra-low carbon steel components, the mark is SPHETi, and the component range is as follows (wt): less than or equal to 0.01 percent of C, less than or equal to 0.80 percent of Si, less than or equal to 0.30 percent of Mn, less than or equal to 0.012 percent of P, less than or equal to 0.012 percent of S, more than or equal to 0.020 percent of Alt, more than or equal to 0.030 percent of Ti, and the balance of Fe and inevitable impurities.
The ultra-low carbon steel-making production process mainly comprises the following steps: molten iron desulfurization → converter → RH → continuous casting → slab heating → rough rolling → finish rolling → coiling. It is recognized in the art that: the ultra-low carbon steel is aluminum deoxidized steel, impurities in the aluminum deoxidized steel are formed in a steel making process and exist in a casting blank, large-size impurities are easy to stay at the lower layer of the surface skin of a raw material along with the reduction of the thickness after hot rolling and cold rolling, and the thickness of the steel for the filter is further reduced in a deep drawing process of a user, so that the probability of the defect of sand holes caused by large-particle impurities is increased greatly, and the sand hole defect is easy to occur.
The basic main difficulty of the steel for the filter is how to effectively reduce the number and the size of inclusions in the steel and ensure the stability of hot rolling and cold rolling, so that the steel for the filter cannot cause a sand hole defect after being stamped by a user. Particularly, it is very difficult to produce steel for a filter by adopting a 100t converter and a matched middle slab caster, because the nominal capacity of the converter is small, the temperature drop of molten steel in the whole steelmaking process is not easy to control, the RH process is easy to blow oxygen, and in addition, the cleanliness of steel for the filter is controlled by controlling the pollution of refractory materials in continuous casting, which is challenging and innovative work.
Disclosure of Invention
The invention aims to provide a production process of a high-quality steel substrate for a filter, which has high product cleanliness.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: the method comprises the working procedures of molten iron desulphurization, converter smelting, RH treatment, medium slab continuous casting, slab heating and hot rolling; the molten iron desulphurization process comprises the following steps: desulfurizing the molten iron until S is less than or equal to 0.005 percent; in the converter smelting process, the final slag alkalinity is 3.5-4.5, 0.020-0.045% of C, less than or equal to 0.010% of S and less than or equal to 0.010% of P in the steel liquid are tapped, the end point temperature is not less than 1690 ℃, the end point oxygen level is controlled at 500-900 ppm, the steel liquid sample is not taken after the converter draws carbon, steel is directly tapped after bottom blowing and strong stirring, and the tapping time is not less than 3 minutes; the RH treatment process adopts a deep decarburization mode, the decarburization time is more than or equal to 14min, and the RH oxygen blowing amount is controlled to be less than or equal to 100m3The vacuum cycle time is more than or equal to 8min after the alloy is added, the C content in the RH discharged molten steel is less than or equal to 0.0030 percent, the Mn content is 0.10 to 0.20 percent, the Si content is less than or equal to 0.010 percent, the S content is less than or equal to 0.012 percent, the P content is less than or equal to 0.012 percent, the Als content is 0.030 to 0.050 percent, the Ti content is 0.050 to 0.070 percent, the N content is less than or equal to 0.0035 percent; in the middle plate blank continuous casting process, the temperature of continuous casting tundish molten steel is 1559-1579 ℃, the baking temperature of the tundish is more than or equal to 1100 ℃, the baking time is more than or equal to 3 hours, secondary cooling adopts a cooling mode combined with dynamic soft reduction, and the withdrawal and straightening temperature is more than or equal to 900 ℃; in the slab heating procedure, the heating temperature is 1150-1310 ℃, and the standing time is controlled within 100-180 min; the hot rolling procedure, the rough rolling speed is not less than1.0m/s, and the finish rolling temperature of finish rolling is 890-930 ℃.
The crystallizer in the medium slab continuous casting process adopts ultra-low carbon steel covering slag, wherein C is 3-8%, and SiO is used224～35％，CaO 25～40％、Al2O32-6%, melting point of 1100 + -50 deg.C, and viscosity of 0.5-2.5 poise.
In the medium slab continuous casting process, O in a casting blank is less than or equal to 25ppm, and N in the casting blank is less than or equal to 40 ppm.
The rough rolling procedure of the invention adopts a reversible rolling mill to carry out 5-pass rolling in a reciprocating way.
The invention adopts a 100t converter and a matched middle slab caster.
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: the production process is stable in control, and the total oxygen and nitrogen contents of the molten steel can be effectively controlled; the hot rolling surface defects are reduced, the class B inclusion of the inclusion grade of the hot rolling substrate is controlled below the fine system grade 1.5, the inclusion structure rating detection method refers to the standard GB/T10561-2005 'microscopic inspection method for measuring standard rating diagram of the content of non-metallic inclusions in steel', the quantity of the hot rolling substrate is detected by using a light mirror, and the size and the component of the hot rolling substrate are analyzed by using an electron microscope. The invention adopts a medium plate blank continuous casting and hot rolling control technology matched with a 100-ton converter to produce the steel substrate for the high-quality filter, produces continuous casting blanks meeting the requirements by controlling process parameters of all working procedures, produces high-quality hot-rolled coils by hot rolling, and finally produces high-quality cold-rolled products by cold rolling.
Drawings
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
FIG. 1 is a light mirror image (100 times) of the steel substrate produced in example 1;
FIG. 2 is a light mirror image (100 times) of the steel substrate produced in example 2;
FIG. 3 is a light mirror image (100 times) of the steel substrate produced in example 3;
FIG. 4 is a light mirror image (100 times) of the steel substrate produced in example 4;
FIG. 5 is a light mirror image (100 times) of the steel substrate produced in example 5;
FIG. 6 is a light mirror image (100 times) of the steel substrate produced in example 6;
FIG. 7 is a light mirror image (100 times) of the steel substrate produced in example 7;
FIG. 8 is a light mirror image (100 times) of the steel substrate produced in example 8;
FIG. 9 is a light mirror image (100 times) of the steel substrate produced in example 9.
Detailed Description
The production process of the steel substrate for the high-quality filter comprises the following process flows: molten iron desulphurization → converter smelting → RH treatment → medium plate blank continuous casting → coping → slab heating → rough rolling → finish rolling → coiling; adopting a converter for 100 t; RH refining for 100 t; continuous casting of medium slab (no electromagnetic stirring), under dynamic soft pressure; the hot rolling adopts a heat accumulating type walking beam slab heating furnace; 4 reversible roughing mills and 7 finishing mill groups are used for producing SPHETi steel; the process is as follows.
(1) Molten iron desulphurization: after the magnesium powder is sprayed into the ladle and the lime is desulfurized, the slag on the surface of the molten iron is removed, and S in the desulfurized molten iron is less than or equal to 0.005 wt%.
(2) Smelting in a converter: a 100t converter is adopted, the temperature of the molten iron entering the converter is more than or equal to 1280 ℃, the C in the molten iron entering the converter is 3.9-4.1%, the S is less than or equal to 0.005%, and the P is less than or equal to 0.130%; the alkalinity of final slag smelted by the converter is 3.5-4.5; smelting in a converter by adopting an automatic steelmaking model; controlling the end point molten steel to be 0.020-0.045 wt% of C, less than or equal to 0.010 wt% of S and less than or equal to 0.010 wt% of P; the end point temperature is more than or equal to 1690 ℃, and the end point oxygen level is controlled to be 500-900 ppm; after carbon drawing, a steel water sample is not taken, the angle of the converter body is recovered to 0 degree, bottom blowing is performed for 120-140 seconds, and the bottom blowing strength is 0.15-0.18 m3T min, directly tapping after strong stirring; tapping time is more than or equal to 3 minutes; using a steel ladle as a turnover steel ladle; a sliding plate front baffle, a slag blocking cone and a sliding plate rear slag blocking are adopted in the steel tapping process; alloying is not carried out in the tapping process, lime is added when molten steel 1/3 is tapped, and the adding amount of the lime is 3.5-4.0 kg per ton of steel. And closing the ladle bottom blowing after the lime is added. And adding a modifier for modifying the slag after tapping, wherein the adding amount of the modifier is 100-200 kg per furnace.
(3) RH treatment: RH adopts a deep decarburization mode, the decarburization time is more than or equal to 14min, and the oxygen level of the molten steel is at the end of the decarburization timeThe concentration is controlled to be 250-400 ppm. The minimum vacuum degree is controlled to be 0.5-2 mbar; RH oxygen blowing amount is less than or equal to 100Nm3. Alloying sequence: after the aluminum deoxidation is finished for 6-8 min, manganese is mixed with manganese metal, titanium and iron are mixed with titanium, the manganese metal → the iron and the iron are added in sequence, and the vacuum circulation time is more than or equal to 8min after the alloy addition is finished. The time to be watered is controlled to be 20-25 min. Controlling (wt) C less than or equal to 0.0030 percent, Mn 0.10-0.20 percent, Si less than or equal to 0.010 percent, S less than or equal to 0.012 percent, P less than or equal to 0.012 percent, Als 0.030-0.050 percent, Ti 0.050-0.070 percent, N less than or equal to 0.0035 percent and O less than or equal to 0.0020 percent of tapping molten steel; the RH leaving temperature is determined according to the section of the casting blank and the continuous casting heat number, and is specifically shown in Table 1.
Table 1: RH leaving temperature
Cross section in mm Pouring into the first furnace, deg.C Continuous casting at low temperature
≤1050 1616～1631 1600～1615
＞1050 1616～1631 1595～1610
(4) And (3) continuous casting of the medium plate blank: the temperature of molten steel of a continuous casting tundish is 1559-1579 ℃, the baking temperature of the tundish is more than or equal to 1100 ℃, the baking time is more than or equal to 3 hours, secondary cooling adopts a cooling mode combined with dynamic soft reduction, and the withdrawal and straightening temperature is more than or equal to 900 ℃; the drawing speed control of different casting blank sections is shown in a table 2; the covering agent without carbon and low silicon is adopted, and the crystallizer adopts ultra-low carbon steel covering slag.
Table 2: corresponding relation between continuous casting drawing speed and casting blank section
Cross section in mm Pulling speed, m/min
≤1050 1.40～1.60
＞1050 1.30～1.50
The ultra-low carbon steel covering slag comprises the following main components in percentage by weight: c3-8% and SiO2 24～35％，CaO 25～40％、Al2O32-6%, melting point of 1100 + -50 deg.C, and viscosity of 0.5-2.5 poise.
In the middle slab continuous casting process, a slag blocking wall and a slag blocking weir are adopted in the tundish; the tundish uses a magnesium refractory, an aluminum-carbon upper nozzle, an aluminum-carbon stopper rod and an immersion nozzle, and the refractory of the tundish is built by coating materials. And sealing and protecting molten steel from a ladle to a tundish by adding argon into a long nozzle.
The obtained casting blank comprises the following chemical components in percentage by weight: less than or equal to 0.003 percent of C, less than or equal to 0.010 percent of Si, 0.10 to 0.20 percent of MnP, less than or equal to 0.012 percent of P, less than or equal to 0.012 percent of S, 0.030 to 0.050 percent of Als, 0.050 to 0.070 percent of Tis, less than or equal to 0.0040 percent of N, less than or equal to 0.0025 percent of O, and the balance of iron and inevitable impurities.
(5) Grinding: and (3) carrying out machine grinding and flame cutting by adopting a grinding machine, wherein the upper surface and the lower surface of the casting blank are required to be cleaned by a machine for 2-4 mm, and the corner of the casting blank is required to be subjected to flame cutting for 2-4 mm.
(6) Heating the plate blank: the heating temperature is 1150-1310 ℃, and the standing time is controlled within 100-180 min.
(7) Hot rolling: the initial rolling temperature of rough rolling is controlled at 1100 +/-20 ℃, a reversing mill is adopted for 5-pass rolling in a reciprocating way, descaling is carried out before each pass of rolling, and the rolling speed of the rough rolling is required to be more than or equal to 1.0 m/s; the total rolling reduction rate of rough rolling is controlled to be more than or equal to 80 percent.
The pressure of the descaling water at the finish rolling inlet is more than or equal to 25 Mpa; the inlet temperature of finish rolling is 1005-1090 ℃, the finish rolling temperature is 890-930 ℃, the total reduction rate of finish rolling is controlled to be not less than 85%, and the thickness of a finished product is 2.0-5.0 mm.
In the coiling process, the coiling temperature is 700-740 ℃; and (3) coiling to obtain the steel substrate for the filter.
(8) The inclusion observation grade of the substrate obtained by the above method is that the B-type inclusions are controlled to be below the fine system 1.5 grade.
Example 1: the production process of the steel substrate for the high-quality filter is specifically described as follows.
(1) Molten iron desulphurization: the molten iron S after desulfurization was 0.005 wt%.
(2) Smelting in a converter: the temperature of the charged molten iron is 1350 ℃, and the charged molten iron contains 4.1% of C, 0.005% of S and 0.110% of P; the alkalinity R of the final slag is 3.95, and the components in the discharged molten steel are as follows: 0.045% of C, 0.009% of S, 0.009% of P and 680ppm of O; end temperature 1705 ℃. Bottom blowing strong stirring for 120 seconds after carbon drawing, wherein the bottom blowing flow is 0.18m3And/t min, directly tapping after strong stirring, wherein the tapping time is 3 minutes. Adding lime when tapping molten steel 1/3, wherein the lime amount is 3.5 kg/ton steel; and after tapping, closing the ladle bottom to blow argon, and adding 100kg of modifier.
(3) RH treatment: the deep decarburization mode is adopted, the minimum vacuum degree is 2.0mbar, and the decarburization time is 14 min. RH oxygen blowing amount is 50Nm3. And after the decarburization time is finished, the oxygen level of the molten steel is 400ppm, aluminum particles are added for deoxidation, circulation is carried out for 6 minutes after the deoxidation is finished, manganese is mixed with manganese metal, titanium is mixed with titanium by titanium iron, the alloy is added with the manganese metal → titanium iron sequentially, and the vacuum circulation time is 8 minutes after the alloying. The RH outbound molten steel components are shown in Table 3, the outbound temperature is 1631 ℃, and the time of the furnace waiting for casting is 25 min.
(4) And (3) continuous casting of the medium plate blank: the heat is the first casting furnace, and the section of a casting blank is 1050 mm. The tundish temperature and the superheat degree are controlled and shown in a table 4, the main component content of the ultra-low carbon steel casting powder is shown in a table 5, and the continuous casting billet component is shown in a table 6; the secondary cooling adopts a cooling mode combined with dynamic soft reduction, the withdrawal and straightening temperature is 900 ℃, and the withdrawal speed is controlled to be 1.6 m/min; the baking temperature of the tundish is 1100 ℃, and the baking time is 3 hours.
(5) A coping process: the upper surface and the lower surface of the casting blank are polished by 4mm, and the corner of the casting blank is cleaned by 4 mm.
(6) A heating procedure: the slab is heated to 1290 +/-20 ℃, and the standing time is 100 min.
(7) A hot rolling procedure: the initial rolling temperature of rough rolling is controlled to be 1100 +/-20 ℃, the rough rolling reduction rate is 80 percent, and the rough rolling strip speed is 1.0 m/s; the start rolling temperature (entrance temperature) of finish rolling is 1025 +/-20 ℃, the reduction rate of the finish rolling is 85%, the descaling water pressure at the entrance of the finish rolling is 25Mpa, and the finish rolling temperature is 900 +/-10 ℃; the coiling temperature is 720 +/-10 ℃, and the thickness of the rolled steel plate is 5.0 mm.
(8) After the steel sheet was produced, the grade and amount of inclusions were observed. Single-particle inclusions were found in the quarter of the width of the plate, 1 μm in width, belonging to the group B inclusions, in a quantity of 3, see FIG. 1. The production process is stable to control, the quality of the obtained steel substrate for the filter is good, the mass fraction of molten steel in the continuous casting tundish is controlled to be 25ppm, the mass fraction of nitrogen is controlled to be 40ppm, the grade B thin system of hot rolled strip steel inclusion is 0.5, and high-quality cold rolled products are finally produced through cold rolling.
Example 2: the production process of the steel substrate for the high-quality filter is specifically described as follows.
(1) Molten iron desulphurization: the molten iron S after desulfurization was 0.003 wt%.
(2) A converter smelting process: the temperature of the molten iron entering the furnace is 1300 ℃, and the molten iron entering the furnace contains 4.0 percent of C, 0.003 percent of S and 0.120 percent of P; the alkalinity R of the final slag is 3.50, and the components in the discharged molten steel are as follows: 0.020% of C, 0.008% of S, 0.010% of P and 720ppm of O; end temperature 1690 ℃. After the carbon is pulled and the stirring is carried out for 140 seconds, the bottom blowing flow is 0.15m3And/t min, directly tapping after strong stirring, wherein the tapping time is 3 minutes. Adding lime when tapping molten steel 1/3, wherein the lime amount is 3.5kg/t steel; after tapping, the bottom of the ladle is closed to blow argon, and the argon is added120kg of the agent.
(3) RH processing procedure: and a deep decarburization mode is adopted, and the decarburization time is 15 min. The lowest vacuum degree is controlled to be 0.5 mbar; RH oxygen blowing amount of 100Nm3. And (3) after the decarburization time is finished, controlling the oxygen level of the molten steel to be 360ppm, adding aluminum particles for deoxidation, circulating for 8 minutes after the deoxidation is finished, using manganese metal to be matched with manganese, using ferrotitanium to be matched with titanium, adding alloy into the manganese metal → ferrotitanium in sequence, and circulating for 8 minutes in vacuum after alloying. The RH outbound molten steel is shown in Table 3, the outbound temperature is 1615 ℃, and the time of the furnace waiting for casting is 20 min.
(4) And (3) a medium slab continuous casting process: the heat is continuous casting heat, and the section of a casting blank is 1050 mm. The tundish temperature is controlled and shown in Table 4, the main component content of the ultra-low carbon steel mold flux is shown in Table 5, and the continuous casting slab component is shown in Table 6. The secondary cooling adopts a cooling mode combined with dynamic soft reduction, the withdrawal and straightening temperature is 920 ℃, and the withdrawal speed is controlled to be 1.4 m/min; the baking temperature of the tundish is 1100 ℃, and the baking time is 3 hours.
(5) A coping process: the upper surface and the lower surface of the casting blank are polished by 2mm, and the corner of the casting blank is cleaned by 2 mm.
(6) A heating procedure: the slab is heated to 1170 +/-20 ℃ and the standing time is 180 min.
(7) A hot rolling procedure: the initial rolling temperature of rough rolling is controlled to be 1100 +/-20 ℃, the rough rolling reduction rate is 80 percent, and the rough rolling strip speed is 2.0 m/s; the start rolling temperature (entrance temperature) of finish rolling is 1070 +/-20 ℃, the reduction rate of the finish rolling is 85%, the descaling water pressure at the entrance of the finish rolling is 25Mpa, and the finish rolling temperature is 920 +/-10 ℃; the coiling temperature is 730 +/-10 ℃, and the thickness of the rolled steel plate is 2.0 mm.
(8) After the steel sheet was produced, the inclusion grade was observed. Single-particle inclusions were found in the quarter of the width of the plate, 5 μm in width, belonging to the group B inclusions, in a quantity of 4, see FIG. 2. The production process is stable to control, the quality of the steel substrate for the filter is good, the mass fraction of oxygen in molten steel of a continuous casting tundish is controlled to be 24ppm, the mass fraction of nitrogen is controlled to be 24ppm, the inclusion grade B thin system of the hot-rolled strip steel is 1.0, and a high-quality cold-rolled product is finally produced through cold rolling.
Example 3: the production process of the steel substrate for the high-quality filter is specifically described as follows.
(1) Molten iron desulphurization: the molten iron S after desulfurization was 0.005 wt%.
(2) A converter smelting process: the temperature of the molten iron entering the furnace is 1280 ℃, 4.0 percent of C, 0.005 percent of S and 0.126 percent of P in the molten iron entering the furnace; the alkalinity R of the final slag is 4.50, and the components in the discharged molten steel are as follows: 0.025 percent of C, 0.010 percent of S, 0.009 percent of P and 900ppm of O; the end point temperature was 1710 ℃. Bottom blowing strong stirring for 130 seconds after carbon drawing, wherein the bottom blowing flow is 0.15m3And/t min, directly tapping after strong stirring, wherein the tapping time is 3.2 minutes. Adding lime when tapping molten steel 1/3, wherein the lime amount is 4.0kg/t steel; and after tapping, closing the bottom of the ladle to blow argon, and adding 200kg of modifier.
(3) RH processing procedure: the deep decarburization mode is adopted, and the decarburization time is 14 min. The lowest vacuum degree is 1.2 mbar; RH was not blown with oxygen. And after the decarburization time is finished, the oxygen level of the molten steel is 400ppm, aluminum particles are added for deoxidation, circulation is carried out for 7 minutes after the deoxidation is finished, manganese metal is used for being matched with manganese, titanium iron is used for being matched with titanium, the alloy is added with the manganese metal → the titanium iron in sequence, and the vacuum circulation time is 9 minutes after the alloying. The RH outbound molten steel is shown in Table 3, the outbound temperature is 1624 ℃, and the time from the outbound of the furnace to the start of casting is 23 min.
(4) And (3) a medium slab continuous casting process: the heat is the first casting furnace, and the section of a casting blank is 1051 mm. The tundish temperature is controlled and shown in Table 4, the main component content of the ultra-low carbon steel covering slag is shown in Table 5, and the continuous casting billet component is shown in Table 6; the secondary cooling adopts a cooling mode combined with dynamic soft reduction, the withdrawal and straightening temperature is 905 ℃, and the withdrawal speed is controlled to be 1.5 m/min; the baking temperature of the tundish is 1100 ℃, and the baking time is 3 hours.
(5) A coping process: the upper surface and the lower surface of the casting blank are polished by 3mm, and the corner of the casting blank is cleaned by 3 mm.
(6) A heating procedure: the slab is heated to 1290 +/-20 ℃, and the standing time is 150 min.
(7) A hot rolling procedure: the initial rolling temperature of rough rolling is controlled to be 1100 +/-20 ℃, the rough rolling reduction rate is 80 percent, and the rough rolling strip speed is 2.0 m/s; the start rolling temperature (entrance temperature) of finish rolling is 1025 +/-20 ℃, the reduction rate of the finish rolling is 86%, the descaling water pressure at the entrance of the finish rolling is 26Mpa, and the finish rolling temperature is 900 +/-10 ℃; the coiling temperature is 710 +/-10 ℃, and the thickness of the rolled steel plate is 3.0 mm.
(8) After the steel sheet was produced, the inclusion grade was observed. Single-particle inclusions were found in the quarter of the width of the plate, 2.5 μm in width, belonging to the group B inclusions, in a quantity of 4, see FIG. 3. The production process is stable to control, the quality of the obtained steel substrate for the filter is good, the mass fraction of molten steel in a continuous casting tundish is controlled to be 25ppm, the mass fraction of nitrogen is controlled to be 33ppm, the grade B thin system of hot rolled strip steel inclusion is 1.0, and high-quality cold rolled products are finally produced through cold rolling.
Example 4: the production process of the steel substrate for the high-quality filter is specifically described as follows.
(1) Molten iron desulphurization: the molten iron S after desulfurization was 0.003 wt%.
(2) A converter smelting process: the temperature of the charged molten iron is 1290 ℃, 4.1 percent of C, 0.003 percent of S and 0.115 percent of P in the charged molten iron; the alkalinity R of the final slag is 4.0, and the components in the discharged molten steel are as follows: 0.040% of C, 0.008% of S, 0.010% of P and 500ppm of O; the end temperature is 1700 ℃. Strong bottom blowing stirring for 130 seconds after carbon drawing, and bottom blowing flow rate of 0.16m3And/t min, directly tapping after strong stirring, wherein the tapping time is 3 minutes. Adding lime when tapping molten steel 1/3, wherein the lime amount is 4.0kg/t steel; and after tapping, closing the ladle bottom to blow argon, and adding 100kg of modifier.
(3) RH processing procedure: the deep decarburization mode is adopted, and the decarburization time is 14 min. The lowest vacuum degree is 0.5 mbar; the oxygen blowing amount is 30Nm3. And after the decarburization time is finished, the oxygen level of the molten steel is 300ppm, aluminum particles are added for deoxidation, circulation is carried out for 7 minutes after the deoxidation is finished, manganese is mixed with manganese metal, titanium is mixed with titanium by ferrotitanium, the alloy is added with manganese metal → ferrotitanium in sequence, and the vacuum circulation time is 8 minutes after the alloying. The composition of the RH outbound molten steel is shown in Table 3; the leaving temperature is 1600 ℃, and the time to be poured is 20 min.
(4) And (3) a medium slab continuous casting process: the heat is continuous casting heat, and the section of a casting blank is 1050 mm. The tundish temperature and the superheat degree are controlled and shown in a table 4, the main component content of the ultra-low carbon steel casting powder is shown in a table 5, and the continuous casting billet component is shown in a table 6; the secondary cooling adopts a cooling mode combined with dynamic soft reduction, the withdrawal and straightening temperature is 925 ℃, and the withdrawal speed is controlled to be 1.5 m/min; the baking temperature of the tundish is 1120 ℃, and the baking time is 3.5 h.
(5) A coping process: the upper surface and the lower surface of the casting blank are polished by 2mm, and the corner of the casting blank is cleaned by 3 mm.
(6) A heating procedure: the slab is heated to 1200 plus or minus 20 ℃, and the standing time is 160 min.
(7) A hot rolling procedure: the initial rolling temperature of rough rolling is controlled at 1100 +/-20 ℃, the rough rolling reduction rate is 80 percent, and the rough rolling strip speed is 5.0 m/s; the start rolling temperature (entrance temperature) of finish rolling is 1025 +/-20 ℃, the reduction rate of the finish rolling is 85%, the descaling water pressure at the entrance of the finish rolling is 26Mpa, and the finish rolling temperature is 900 +/-10 ℃; the coiling temperature is 710 +/-10 ℃, and the thickness of the rolled steel plate is 5.0 mm.
(8) After the steel sheet was produced, the inclusion grade was observed. Single-particle inclusions were found in the quarter of the width of the plate, 10 μm in width, belonging to the group B inclusions, in a quantity of 5, see FIG. 4. The production process of the embodiment is stable in control, the quality of steel for the filter is good, the oxygen mass fraction of molten steel of the continuous casting tundish is controlled to be 16ppm, the nitrogen mass fraction is controlled to be 28ppm, the inclusion grade B thin system of the hot-rolled strip steel is 1.5, and a high-quality cold-rolled product is finally produced through cold rolling.
Example 5: the production process of the steel substrate for the high-quality filter is specifically described as follows.
(1) Molten iron desulphurization: the molten iron S after desulfurization was 0.001 wt%.
(2) A converter smelting process: the temperature of the molten iron entering the furnace is 1330 ℃, and the molten iron entering the furnace contains 3.9% of C, 0.001% of S and 0.110% of P; the alkalinity R of the final slag is 4.0, and the components in the discharged molten steel are as follows: 0.025% of C, 0.007% of S, 0.009% of P and 900ppm of O; end temperature 1690 ℃. Bottom blowing strong stirring blowing for 120 seconds after carbon drawing, wherein the bottom blowing flow is 0.17m3And/t min, directly tapping after strong stirring, wherein the tapping time is 3.3 minutes. Adding lime when tapping molten steel 1/3, wherein the adding amount of lime is 3.7kg/t steel; and after tapping, closing the bottom of the ladle to blow argon, and adding 200kg of modifier.
(3) RH processing procedure: the deep decarburization mode is adopted, and the decarburization time is 14 min. The minimum vacuum degree is 1 mbar; RH oxygen blowing amount of 100Nm3. And after the decarburization time is finished, the oxygen level of the molten steel is 400ppm, aluminum particles are added for deoxidation, circulation is carried out for 6 minutes after the deoxidation is finished, manganese metal is used for being matched with manganese, titanium iron is used for being matched with titanium, the alloy is added with the manganese metal → the titanium iron in sequence, and the vacuum circulation time is 10 minutes after the alloying. The RH outbound molten steel is shown in Table 3, the outbound temperature is 1610 ℃, and the time of the furnace waiting for casting is 20 min.
(4) And (3) a medium slab continuous casting process: the heat is continuous casting heat, and the section of a casting blank is 1051 mm. The tundish temperature and the superheat degree are controlled and shown in a table 4, the main component content of the ultra-low carbon steel casting powder is shown in a table 5, and the continuous casting billet component is shown in a table 6; the secondary cooling adopts a cooling mode combined with dynamic soft reduction, the withdrawal and straightening temperature is 925 ℃, and the withdrawal speed is controlled to be 1.3 m/min; the baking temperature of the tundish is 1100 ℃, and the baking time is 3.2 h.
(5) A coping process: the upper surface and the lower surface of the casting blank are polished by 3mm, and the corner of the casting blank is cleaned by 2 mm.
(6) A heating procedure: the slab is heated to 1290 +/-20 ℃, and the standing time is 120 min.
(7) A hot rolling procedure: the initial rolling temperature of rough rolling is controlled to be 1100 +/-20 ℃, the rough rolling reduction rate is 85 percent, and the rough rolling strip speed is 5.0 m/s; the start rolling temperature (entrance temperature) of finish rolling is 1070 +/-20 ℃, the reduction rate of the finish rolling is 85%, the descaling water pressure at the entrance of the finish rolling is 28Mpa, and the finish rolling temperature is 920 +/-10 ℃; the coiling temperature is 730 +/-10 ℃, and the thickness of the rolled steel plate is 2.0 mm.
(8) After the steel sheet was produced, the inclusion grade was observed. Single-particle inclusions were found in the quarter of the width of the plate, 5 μm in width, belonging to the group B inclusions, in a quantity of 5, see FIG. 5. The production process of the embodiment is stable in control, the quality of steel for the filter is good, the oxygen mass fraction of molten steel of the continuous casting tundish is controlled to be 17ppm, the nitrogen mass fraction is controlled to be 24ppm, the inclusion grade B thin system of the hot-rolled strip steel is 1.5, and a high-quality cold-rolled product is finally produced through cold rolling.
Example 6: the production process of the steel substrate for the high-quality filter is specifically described as follows.
(1) Molten iron desulphurization: the molten iron S after desulfurization is 0.004 wt%.
(2) A converter smelting process: the temperature of the molten iron entering the furnace is 1330 ℃, and the molten iron entering the furnace contains 4.1 percent of C, 0.004 percent of S and 0.130 percent of P; the alkalinity R of the final slag is 3.95, and the components in the discharged molten steel are as follows: 0.020% of C, 0.008% of S, 0.009% of P and 750ppm of O; end temperature 1705 ℃. Bottom blowing strong stirring is carried out for 140 seconds after carbon drawing, and the bottom blowing flow is 0.18m3And/t min, directly tapping after strong stirring, wherein the tapping time is 3 minutes. Adding lime when tapping molten steel 1/3, wherein the adding amount of lime is 4.0kg/t steel; after tapping, closing the ladle bottom to blow argon, adding150kg of modifier is added.
(3) RH processing procedure: the deep decarburization mode is adopted, and the decarburization time is 14 min. The lowest vacuum degree is 1.5 mbar; oxygen blowing amount of 60Nm3. And after the decarburization time is finished, the oxygen level of the molten steel is 250ppm, aluminum particles are added for deoxidation, circulation is carried out for 6 minutes after the deoxidation is finished, manganese is mixed with manganese metal, titanium is mixed with titanium iron, the alloy is added with the manganese metal → titanium iron sequentially, and the vacuum circulation time is 8 minutes after the alloying. The RH outbound molten steel is shown in Table 3, the outbound temperature is 1616 ℃, and the time of the furnace waiting for casting is 22 min.
(4) And (3) a medium slab continuous casting process: the heat is the first casting heat, and the section of a casting blank is 1050 mm. The tundish temperature is controlled and shown in Table 4, the main component content of the ultra-low carbon steel covering slag is shown in Table 5, and the continuous casting billet component is shown in Table 6; the secondary cooling adopts a cooling mode combined with dynamic soft reduction, the withdrawal and straightening temperature is 925 ℃, and the withdrawal speed is controlled to be 1.5 m/min; the baking temperature of the tundish is 1150 ℃, and the baking time is 3 h.
(5) A coping process: the upper surface and the lower surface of the casting blank are polished for 4mm, and the corner of the casting blank is cleaned for 2 mm.
(6) A heating procedure: the slab is heated to 1220 plus or minus 20 ℃ and the furnace residence time is 160 min.
(7) A hot rolling procedure: the initial rolling temperature of rough rolling is controlled at 1100 +/-20 ℃, the rough rolling reduction rate is 82 percent, and the rough rolling strip speed is 2.0 m/s; the start rolling temperature (entrance temperature) of finish rolling is 1050 +/-20 ℃, the reduction rate of finish rolling is 85%, the descaling water pressure at the entrance of finish rolling is 26Mpa, and the finish rolling temperature is 910 +/-10 ℃; the coiling temperature is 730 +/-10 ℃, and the thickness of the rolled steel plate is 4.0 mm.
(8) After the steel sheet was produced, the inclusion grade was observed. Single-particle inclusions were found in the quarter of the width of the plate, 50 μm in width, belonging to the group B inclusions, in a number of 2, see FIG. 6. The production process of the embodiment is stable in control, the quality of steel for the filter is good, the oxygen mass fraction of molten steel of the continuous casting tundish is controlled to be 20ppm, the nitrogen mass fraction is controlled to be 25ppm, the inclusion grade B thin system of the hot-rolled strip steel is 1.0, and the high-quality cold-rolled product is finally produced through cold rolling.
Example 7: the production process of the steel substrate for the high-quality filter is specifically described as follows.
(1) Molten iron desulphurization: the molten iron S after desulfurization is 0.004 wt%.
(2) A converter smelting process: the temperature of the charged molten iron is 1350 ℃, and the charged molten iron contains 4.1% of C, 0.004% of S and 0.110% of P; the alkalinity R of the final slag is 3.80, and the components in the discharged molten steel are as follows: 0.032% of C, 0.008% of S, 0.010% of P and 800ppm of O; end temperature 1690 ℃. Bottom blowing strong stirring for 120 seconds after carbon drawing, wherein the bottom blowing flow is 0.16m3And/t min, directly tapping after strong stirring, wherein the tapping time is 3.5 minutes. Adding lime when tapping molten steel 1/3, wherein the adding amount of lime is 3.75kg/t steel; and after tapping, closing the ladle bottom to blow argon, and adding 150kg of modifier.
(3) RH processing procedure: and a deep decarburization mode is adopted, and the decarburization time is 16 min. The lowest vacuum degree is 1 mbar; oxygen blowing amount of 100Nm for RH oxygen blowing temperature rise3. And after the decarburization time is finished, controlling the oxygen level of molten steel to be 300ppm, adding aluminum particles for deoxidation, circulating for 6 minutes after the deoxidation is finished, using manganese metal to be matched with manganese, using ferrotitanium to be matched with titanium, adding alloy into the manganese metal → ferrotitanium in sequence, and performing vacuum circulation for 10 minutes after alloying. The composition of the RH outbound molten steel is shown in Table 3, the outbound temperature is 1595 ℃, and the time from the outbound of the furnace to the start of casting is 25 min.
(4) And (3) a medium slab continuous casting process: the heat is continuous casting heat, and the section of a casting blank is 1151 mm. The tundish temperature is controlled and shown in Table 4, the main component content of the ultra-low carbon steel covering slag is shown in Table 5, and the continuous casting billet component is shown in Table 6; the secondary cooling adopts a cooling mode combined with dynamic soft reduction, the withdrawal and straightening temperature is 925 ℃, and the withdrawal speed is controlled to be 1.4 m/min; the tundish adopts a slag stopping wall and a slag stopping weir, the baking temperature of the tundish is 1100 ℃, and the baking time is 3 hours.
(5) A coping process: the upper and lower surfaces are polished by 3mm, and the corners of the casting blank are cleaned by 4 mm.
(6) A heating procedure: the slab is heated to 1240 +/-20 ℃, and the standing time is 100 min.
(7) A hot rolling procedure: the initial rolling temperature of rough rolling is controlled at 1100 +/-20 ℃, the rough rolling reduction rate is 80 percent, and the rough rolling strip speed is 5.0 m/s; the start rolling temperature (entrance temperature) of finish rolling is 1040 +/-20 ℃, the reduction rate of finish rolling is 88%, the descaling water pressure at the entrance of finish rolling is 26Mpa, and the finish rolling temperature is 900 +/-10 ℃; the coiling temperature is 720 +/-10 ℃, and the thickness of the rolled steel plate is 3.0 mm.
(8) After the steel sheet was produced, the inclusion grade was observed. Single-particle inclusions were found in one quarter of the width of the plate, 55 μm in width, belonging to the group B inclusions, in a quantity of 3, see FIG. 7. The production process of the embodiment is stable in control, the quality of steel for the filter is good, the oxygen mass fraction of molten steel of the continuous casting tundish is controlled to be 18ppm, the nitrogen mass fraction is controlled to be 40ppm, the inclusion grade B thin system of hot rolled strip steel is 1.0, and a high-quality continuous annealing product is finally produced through cold rolling.
Example 8: the production process of the steel substrate for the high-quality filter is specifically described as follows.
(1) Molten iron desulphurization: the molten iron S after desulfurization was 0.002 wt%.
(2) A converter smelting process: the temperature of the molten iron entering the furnace is 1300 ℃, and the molten iron entering the furnace contains 3.9% of C, 0.003% of S and 0.120% of P; the alkalinity R of the final slag is 3.75, and the components in the discharged molten steel are as follows: 0.028% of C, 0.008% of S, 0.008% of P and 560ppm of O; end temperature 1695 ℃. After strong stirring for 135 seconds after carbon drawing, the bottom blowing flow is 0.17m3And/t min, directly tapping after strong stirring, wherein the tapping time is 3.0 minutes. Adding lime when tapping molten steel 1/3, wherein the lime amount is 3.6kg/t steel; and after tapping, closing the ladle bottom to blow argon, and adding 170kg of modifier.
(3) RH processing procedure: and a deep decarburization mode is adopted, and the decarburization time is 15 min. The lowest vacuum degree is controlled to be 0.8 mbar; RH oxygen blowing amount of 85Nm3. And after the decarburization time is finished, the oxygen level of the molten steel is 280ppm, aluminum particles are added for deoxidation, circulation is carried out for 7 minutes after the deoxidation is finished, manganese metal is used for being matched with manganese, titanium iron is used for being matched with titanium, the alloy is added with the manganese metal → the titanium iron in sequence, and the vacuum circulation time is 8 minutes after the alloying. The RH outbound molten steel is shown in Table 3, the outbound temperature is 1616 ℃, and the time of the furnace waiting for casting is 24 min.
(4) And (3) a medium slab continuous casting process: the heat is the first casting furnace, and the section of a casting blank is 1051 mm. The tundish temperature is controlled and shown in Table 4, the main component content of the ultra-low carbon steel mold flux is shown in Table 5, and the continuous casting slab component is shown in Table 6. The secondary cooling adopts a cooling mode combined with dynamic soft reduction, the withdrawal and straightening temperature is 910 ℃, and the withdrawal speed is controlled to be 1.45 m/min; the baking temperature of the tundish is 1130 ℃, and the baking time is 3.5 h.
(5) A coping process: the upper surface and the lower surface of the casting blank are polished by 3mm, and the corner of the casting blank is cleaned by 4 mm.
(6) A heating procedure: the slab is heated to 1270 +/-20 ℃, and the standing time is 140 min.
(7) A hot rolling procedure: the initial rolling temperature of rough rolling is controlled to be 1100 +/-20 ℃, the rough rolling reduction rate is 80 percent, and the rough rolling strip speed is 3.0 m/s; the start rolling temperature (entrance temperature) of the finish rolling is 1035 +/-20 ℃, the reduction rate of the finish rolling is 87 percent, the descaling water pressure at the entrance of the finish rolling is 27Mpa, and the finish rolling temperature is 915 +/-10 ℃; the coiling temperature is 715 +/-10 ℃, and the thickness of the rolled steel plate is 3.0 mm.
(8) After the steel sheet was produced, the inclusion grade was observed. Single-particle inclusions were found in the quarter of the width of the plate, 5 μm in width, belonging to the group B inclusions, in a number of 4. The production process is stable in control, the quality of the steel substrate for the filter is good, the mass fraction of oxygen in molten steel of a continuous casting tundish is controlled to be 19ppm, the mass fraction of nitrogen is controlled to be 35ppm, the inclusion grade B thin system of the hot-rolled strip steel is 1.0, and a high-quality cold-rolled product is finally produced through cold rolling.
Example 9: the production process of the steel substrate for the high-quality filter is specifically described as follows.
(1) Molten iron desulphurization: the molten iron S after desulfurization was 0.003 wt%.
(2) A converter smelting process: the temperature of the molten iron entering the furnace is 1280 ℃, 4.1% of C, 0.005% of S and 0.122% of P in the molten iron entering the furnace; the alkalinity R of the final slag is 4.20, and the components in the discharged molten steel are as follows: 0.041 percent of C, 0.009 percent of S, 0.008 percent of P and 850ppm of O; end point temperature 1715 ℃. Bottom blowing strong stirring is carried out for 125 seconds after carbon drawing, and the bottom blowing flow is 0.17m3And/t min, directly tapping after strong stirring, wherein the tapping time is 3.5 minutes. Adding lime when tapping molten steel 1/3, wherein the lime amount is 3.8kg/t steel; and after tapping, closing the ladle bottom to blow argon, and adding 160kg of modifier.
(3) RH processing procedure: and a deep decarburization mode is adopted, and the decarburization time is 15 min. The lowest vacuum degree is 1.7 mbar; RH oxygen blowing amount of 70Nm3. And after the decarburization time is finished, the oxygen level of the molten steel is 350ppm, aluminum particles are added for deoxidation, circulation is carried out for 7 minutes after the deoxidation is finished, manganese metal is used for being matched with manganese, titanium iron is used for being matched with titanium, the alloy is added with the manganese metal → the titanium iron in sequence, and the vacuum circulation time is 10 minutes after the alloying. RH outbound molten steel is shown in Table 3, the outbound temperature is 1631 ℃, and the furnace is outbound to the beginning of castingThe time period is 21 min.
(4) And (3) a medium slab continuous casting process: the heat is the first casting furnace, and the section of a casting blank is 1051 mm. The tundish temperature is controlled and shown in Table 4, the main component content of the ultra-low carbon steel covering slag is shown in Table 5, and the continuous casting billet component is shown in Table 6; the secondary cooling adopts a cooling mode combined with dynamic soft reduction, the withdrawal and straightening temperature is 915 ℃, and the withdrawal speed is controlled to be 1.35 m/min; the baking temperature of the tundish is 1110 ℃, and the baking time is 3.3 h.
(5) A coping process: the upper surface and the lower surface of the casting blank are polished by 4mm, and the corner of the casting blank is cleaned by 3 mm.
(6) A heating procedure: the slab is heated to 1230 +/-20 ℃, and the standing time is 130 min.
(7) A hot rolling procedure: the initial rolling temperature of rough rolling is controlled to be 1100 +/-20 ℃, the rough rolling reduction rate is 81 percent, and the rough rolling strip speed is 4.0 m/s; the start rolling temperature (entrance temperature of finish rolling) of finish rolling is 1060 +/-20 ℃, the reduction rate of finish rolling is 87%, the descaling water pressure at the entrance of finish rolling is 30Mpa, and the finish rolling temperature is 905 +/-10 ℃; the coiling temperature is 725 +/-10 ℃, and the thickness of the rolled steel plate is 4.0 mm.
(8) After the steel sheet was produced, the inclusion grade was observed. Single-particle inclusions were found in the quarter of the width of the plate, 2.5 μm in width, belonging to the group B inclusions, in a number of 4. The production process is stable to control, the quality of the steel substrate for the filter is good, the mass fraction of oxygen in molten steel of the continuous casting tundish is controlled to be 22ppm, the mass fraction of nitrogen is controlled to be 26ppm, the inclusion grade B thin system of the hot-rolled strip steel is 1.0, and the high-quality cold-rolled product is finally produced through cold rolling.
Table 3: RH outbound chemical composition and content (wt%) in each example
Figure BDA0001993687550000141
Figure BDA0001993687550000151
In table 3, the balance is Fe and inevitable impurities.
Table 4: tundish temperature (. degree. C.) in each example
Figure BDA0001993687550000152
Figure BDA0001993687550000161
Table 5: the content (wt) of the main component of the ultra-low carbon steel mold flux in each example
Figure BDA0001993687550000162
Table 6: the chemical composition and content (wt%) of the cast blank in each example
Figure BDA0001993687550000163
Figure BDA0001993687550000171

Claims (4)

1. A production process of a steel substrate for a high-quality filter is characterized by comprising the following steps: the method comprises the working procedures of molten iron desulphurization, converter smelting, RH treatment, medium slab continuous casting, coping, slab heating and hot rolling; the molten iron desulphurization process comprises the following steps: desulfurizing the molten iron until S is less than or equal to 0.005 percent; in the converter smelting process, the final slag alkalinity is 3.5-4.5, 0.020-0.045% of C, less than or equal to 0.010% of S and less than or equal to 0.010% of P in the steel liquid are tapped, the end point temperature is not less than 1690 ℃, the end point oxygen level is controlled at 500-900 ppm, the steel liquid sample is not taken after the converter draws carbon, steel is directly tapped after bottom blowing and strong stirring, and the tapping time is not less than 3 minutes; the RH processing procedure adopts a deep decarburization mode, the decarburization time is more than or equal to 14min, the RH oxygen blowing amount is controlled to be less than or equal to 100m3, the vacuum cycle time is more than or equal to 8min after the alloy is added, the C in the RH discharged molten steel is less than or equal to 0.0030%, the Mn is 0.10% -0.20%, the Si is less than or equal to 0.010%, the S is less than or equal to 0.012%, the P is less than or equal to 0.012%, the Als is 0.030% -0.050%, the Ti is 0.050% -0.070%, the N is less than or equal to 0.0035; in the middle plate blank continuous casting process, the temperature of continuous casting tundish molten steel is 1559-1579 ℃, the baking temperature of the tundish is more than or equal to 1100 ℃, the baking time is more than or equal to 3 hours, secondary cooling adopts a cooling mode combined with dynamic soft reduction, and the withdrawal and straightening temperature is more than or equal to 900 ℃; in the slab heating procedure, the heating temperature is 1150-1310 ℃, and the standing time is controlled within 100-180 min; in the hot rolling procedure, the rough rolling speed is more than or equal to 1.0m/s, and the finish rolling temperature of finish rolling is 890-930 ℃;
the obtained casting blank comprises the following chemical components in percentage by weight: less than or equal to 0.003 percent of C, less than or equal to 0.010 percent of Si, 0.10 to 0.20 percent of Mn, less than or equal to 0.012 percent of P, less than or equal to 0.012 percent of S, 0.030 to 0.050 percent of Als, 0.050 to 0.070 percent of Ti, less than or equal to 0.0040 percent of N, less than or equal to 0.0025 percent of O, and the balance of iron and inevitable impurities.
2. The process for producing a steel substrate for a high-quality filter according to claim 1, wherein: the crystallizer in the middle slab continuous casting process adopts ultra-low carbon steel covering slag, wherein the ultra-low carbon steel covering slag comprises 3-8% of C, 224-35% of SiO, 25-40% of CaO and 78-6% of Al2O 32, the melting point is 1100 +/-50 ℃, and the viscosity is 0.5-2.5 poise.
3. The process for producing a steel substrate for a high-quality filter according to claim 1, wherein: in the rough rolling procedure, a reversible rolling mill is adopted for 5 reciprocating rolling passes.
4. The production process for a steel substrate for a high-quality filter according to any one of claims 1 to 3, wherein: the method adopts a 100t converter and a matched medium slab continuous casting machine and a hot rolling production line.
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CN106148821B (en) * 2016-07-13 2018-04-10 唐山钢铁集团有限责任公司 Phosphorate the production technology of high-strength IF steel
CN106148803B (en) * 2016-08-30 2017-11-24 唐山钢铁集团有限责任公司 A kind of production method of deep-draw battery case steel
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CN108728751B (en) * 2018-06-25 2020-07-14 新余钢铁股份有限公司 IF isotropic steel for improving stamping forming and manufacturing method thereof
CN109136444A (en) * 2018-08-30 2019-01-04 唐山钢铁集团有限责任公司 Quickly, the new energy car battery shell steel and production method of punch process is thinned

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