CN116949349A - Production method of high-sulfur low-aluminum nitrogen-containing steel - Google Patents

Production method of high-sulfur low-aluminum nitrogen-containing steel Download PDF

Info

Publication number
CN116949349A
CN116949349A CN202310958038.9A CN202310958038A CN116949349A CN 116949349 A CN116949349 A CN 116949349A CN 202310958038 A CN202310958038 A CN 202310958038A CN 116949349 A CN116949349 A CN 116949349A
Authority
CN
China
Prior art keywords
molten steel
furnace
als
sample
feeding
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.)
Pending
Application number
CN202310958038.9A
Other languages
Chinese (zh)
Inventor
黄含哲
寻忠忠
戴文笠
曾令宇
王冠
余大华
刘志龙
覃小峰
鲁金龙
李至荣
龙鹄
任世岗
叶德新
胡现锋
黎莉
徐忠
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Guangdong Zhongnan Iron and Steel Co Ltd
Original Assignee
Guangdong Zhongnan Iron and Steel Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Guangdong Zhongnan Iron and Steel Co Ltd filed Critical Guangdong Zhongnan Iron and Steel Co Ltd
Priority to CN202310958038.9A priority Critical patent/CN116949349A/en
Publication of CN116949349A publication Critical patent/CN116949349A/en
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/04—Making ferrous alloys by melting
    • C22C33/06—Making ferrous alloys by melting using master 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
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/0006—Adding metallic additives
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/0056—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 using cored wires
    • 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
    • C21C7/0075—Treating in a ladle furnace, e.g. up-/reheating of molten steel within the ladle
    • 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
    • C21C7/0087—Treatment of slags covering the steel bath, e.g. for separating slag from the molten metal
    • 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
    • C21C7/10—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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • 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
    • 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
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • 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
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Landscapes

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

Abstract

The application discloses a production method of high-sulfur low-aluminum nitrogen-containing steel, which reversely aims at RH according to the characteristics of steel types and the actual requirements of the superheat degree of tundish molten steel,The LF, ar station and converter molten steel treatment process is designed, so that the final slag of the LF furnace is low-alkalinity slag and is stable, and if a high-alkalinity and high-temperature method is adopted in the corresponding LF process, the S yield is abnormally low; meanwhile, the application reduces the Al which is not removed in the steel under the condition of ensuring that the deoxidation of the molten steel is not poor 2 O 3 Thereby reducing nozzle clogging; in addition, the tundish stopper adopts an argon blowing method, can remove the inclusion in the molten steel of the tundish to the maximum extent, reducing the nodulation of the water gap and ensuring the number of continuous casting furnaces and the quality of casting blanks.

Description

Production method of high-sulfur low-aluminum nitrogen-containing steel
Technical Field
The application relates to the technical field of steel smelting, in particular to a production method of high-sulfur low-aluminum nitrogen-containing steel.
Background
Some of the prior art reasonably utilizes certain iron and steel smelting byproducts, such as blast furnace sulfur-containing slag, to reduceThe production cost relates to a sulfur-increasing method (CN 106834594A) of sulfur-containing steel, a method (CN 113201620B) for smelting sulfur-containing steel by utilizing desulfurization residues, and the like; some are considered from the view point of a process path, such as whether to use molten iron pretreatment, a primary smelting furnace (an electric furnace, a converter and the like), an LF refining furnace, whether to continue to use some refining furnaces with stronger capability (RH furnaces and VD furnaces), continuous casting, steel rolling and the like, and relate to a smelting method (CN 103146883A) of patent sulfur-containing low-oxygen gear steel, a method (CN 113718081A) for improving the continuous drawing furnace number of sulfur-containing gear steel and the like. For steel containing S and Al, the difference of the process of a refining furnace is larger mainly in terms of improving the quality of the product, LF final slag is mainly divided into two main types of low-alkali slag system and high-alkali slag system no matter whether LF adopts a slag changing process or not, wherein the low-alkali slag system has the advantages of effectively improving the yield of S in S-containing materials during S increase, but steel slag has the advantages of reducing the cost of Al 2 O 3 The adsorption capacity of inclusions becomes weak, and once the LF process adopts too much Al-containing deoxidizer, the Al in the steel is not removed 2 O 3 Is easy to become a source of water shutoff inclusions; the advantage of high alkalinity slag system combined with aluminum deoxidation is that the cleanliness of molten steel can be effectively improved, but the S content of the steel slag is higher, the S yield in S-containing materials is lower when S is increased, and the cost is increased.
In view of this, the present application has been made.
Disclosure of Invention
The application aims to provide a method for producing high-sulfur low-aluminum nitrogen-containing steel, which solves the problem that the Al in the steel is not removed 2 O 3 A problem of clogging the nozzle.
The application is realized in the following way:
in a first aspect, the application provides a method for producing a high-sulfur low-aluminum nitrogen-containing steel, comprising:
converter smelting, wherein the free oxygen content at the end point of the converter is controlled to be less than or equal to 350ppm, then tapping is carried out, deoxidizing is carried out during tapping, and the Als of an Ar station after deoxidizing is 0.018-0.028 wt%;
refining in an LF furnace, adding 350-400kg of lime, 500-550kg of low-alkalinity slag and 170-230kg of silicon carbide or ferrosilicon powder into 135-142t molten steel when the molten steel is in the LF furnace, and obtaining steel slag with binary alkalinity of W (CaO)/W (SiO) 2 )＝1.5-2.0、CaO 44wt％-48wt％、SiO 2 24wt％-28wt％、Al 2 O 3 14 to 18 weight percent, 1.5 to less than or equal to TFe+MnO to less than or equal to 3.0 weight percent, 4 to 9 weight percent of MgO, and the main components of the LF outbound molten steel are more than or equal to 0.007 weight percent of Als, 0.058 to 0.060 weight percent of S, 40 to 60ppm of N and 5 to 18ppm of free oxygen;
vacuum treatment of RH furnace, and circulating current N is used in the whole process of the RH furnace for molten steel 2 The gas circulation is carried out, wherein, after molten steel enters an RH furnace, vacuum pumping is carried out for 10pa-60pa for 8min-15min in 2min-5min, then vacuum degree is adjusted to 5000pa-6000pa for 12min-15min, and then the pressure is increased to atmospheric pressure, and the N content of the molten steel is 60ppm-80ppm;
and in the continuous casting process, the superheat degree of the molten steel in the tundish is 32-42 ℃ during the whole casting period of the molten steel, argon is blown from a continuous casting stopper rod, and the argon blowing flow is 1NL/min-10NL/min.
In an alternative embodiment, the LF1 is sampled after power transmission for 5-10 min after the addition of the low-alkalinity slag is finished;
preferably, if Als of Ar station after deoxidation in the converter smelting step is less than 0.018wt%, sampling after molten steel reaches an LF furnace to confirm the Als content in the molten steel, and if Als is less than or equal to 0.016wt%, feeding an aluminum wire until the Als content is 0.020wt%;
preferably, if Als of an Ar station after deoxidation in the converter smelting step is more than 0.028wt%, sampling and confirming the Als content in the molten steel after the molten steel reaches an LF furnace, if Als is more than or equal to 0.024wt%, increasing bottom blowing flow to Q before the sample LF1, wherein Q is more than or equal to 4, and the time of the bottom blowing flow is 8-14 min;
preferably, if Als of the sample LF1 is less than or equal to 0.016wt%, the aluminum wire is added to an Als of 0.016wt%.
In an alternative embodiment, in the LF refining step, 350-400kg of lime is gradually added after molten steel is fed to a station for 1min, and 500-550kg of low-alkalinity slag is added within 10-15 min after lime addition is finished;
preferably, 110kg-120kg of silicon carbide or ferrosilicon powder is added before the sample LF1 starts to add lime to the sample LF1, and 60kg-110kg of silicon carbide or ferrosilicon powder is gradually added into molten steel in the subsequent LF furnace refining step;
preferably, sampling is recorded as a sample A8-12 min before the molten steel of the LF station is out of the station, the S content in the sample A is more than or equal to 0.050wt%, and S is supplemented to 0.058-0.060 wt% according to the sample A within 5min after the molten steel of the LF station is out of the station;
in an alternative embodiment, the time of molten steel at an LF station is less than or equal to 100min, ar gas bottom blowing smelting is adopted in the whole LF furnace, and N-containing alloy is not added in the whole LF furnace, so that the molten steel naturally increases N.
In an alternative embodiment, taking a steel sample from the molten steel to an RH station, marking the steel sample as a sample RH1, adding aluminum particles to increase the Als content to 0.023wt% when the vacuum degree reaches 10pa-60pa and 2min-3min after the vacuum degree reaches 10pa-60pa, and adding ferrotitanium to increase the Ti content to 0.016wt% when the vacuum degree reaches 6min-10min after the vacuum degree reaches 10pa-60 pa.
In an alternative embodiment, the sample is recorded as sample RH 24 min-6min prior to RH repression; after the RH furnace is repressed, feeding Mn-N lines, wherein the feeding quantity of the Mn-N lines is 200 m/furnace-250 m/furnace; feeding Ca wires, wherein the feeding quantity of the Ca wires is 60 m/furnace-80 m/furnace, the feeding speed of the Ca wires is 250m/min-300m/min, and the interval between the Ca wires and the front feeding wires is 3.8min-4.2min;
preferably, the carbonized rice husk is added to be more than or equal to 28kg after the Mn-N line is fed;
preferably, soft blowing is started after Ca wire feeding is completed, and the soft blowing time is 20 min/furnace-30 min/furnace.
In an alternative embodiment, if S is less than 0.055wt% in sample RH2, the sulfur line is fed 0.8min-1.2min after Mn-N line feed until S content increases to 0.055wt%, and the sulfur line parameters are: the weight of the core powder is 195g/m-205g/m, and S in the core powder is more than or equal to 99wt%;
in an alternative embodiment, if Als in sample RH2 is less than 0.017wt%, then feeding Al wire 1.8min-2.2min after feeding S wire to increase Als content to 0.017wt%, and if S wire is not fed, feeding Al wire 1.8min-2.2min after feeding Mn-N wire to increase Als content to 0.017wt%; the calcium line is fed after the S line is fed.
In an alternative embodiment, a high temperature region of 15min-25min exists after sampling LF1, and the temperature of the high temperature region is 1640-1660 ℃;
in an alternative embodiment, the topping furnace RH to station temperature is 1630 ℃ to 1635 ℃ and the RH to station temperature is 1553 ℃ to 1558 ℃; and/or the RH arrival temperature of the casting continuous casting furnace is 1631 ℃ at 1626 ℃ and the RH outbound temperature is 1548-1553 ℃.
In a second aspect, the application provides the high-sulfur low-aluminum nitrogen-containing steel obtained by the production method of the high-sulfur low-aluminum nitrogen-containing steel, wherein the liquidus temperature is 1483-1485 ℃, and the steel comprises 0.39-0.41 wt% of C, 0.67-0.73 wt% of Si, 0.50-0.60 wt% of S, 1.36-1.44 wt% of Mn, 0.013-0.017 wt% of Ti, 0.09-0.017 wt% of Als, 90-150 ppm of N and less than or equal to 2ppm of H.
The application has the following beneficial effects:
according to the characteristics of steel components, actual requirements of the superheat degree of the molten steel in the tundish and the like, the application designs the RH, LF, ar station and converter molten steel treatment processes reversely, so that the final slag of the LF furnace is low-alkalinity slag and is stable, and the yield of S is abnormally low if a high-alkalinity and high-temperature method is adopted in the corresponding LF process; meanwhile, the application reduces the Al which is not removed in the steel under the condition of ensuring that the deoxidation of the molten steel is not poor 2 O 3 Thereby reducing nozzle clogging; in addition, the tundish stopper rod adopts an argon blowing method, so that inclusions in the tundish molten steel can be removed to the maximum extent, nozzle knots are reduced, and the number of continuous casting furnaces and the quality of casting blanks are ensured.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
The embodiment provides a production method of high-sulfur low-aluminum nitrogen-containing steel, which comprises the following steps:
converter smelting, wherein the free oxygen content at the end point of the converter is controlled to be less than or equal to 350ppm, then tapping is carried out, deoxidizing is carried out during tapping, and the Als of an Ar station after deoxidizing is 0.018-0.028 wt%;
refining in an LF furnace, adding 350-400kg of lime, 500-550kg of low-alkalinity slag and 170-230kg of silicon carbide or ferrosilicon powder into 135-142t molten steel when the molten steel is in the LF furnace, and obtaining steel slag with binary alkalinity of W (CaO)/W (SiO) 2 )
＝1.5-2.0、CaO 44wt％-48wt％、SiO 2 24wt％-28wt％、Al 2 O 3 14 to 18 weight percent, 1.5 to less than or equal to TFe+MnO to less than or equal to 3.0 weight percent, 4 to 9 weight percent of MgO, and the main components of the LF outbound molten steel are more than or equal to 0.007 weight percent of Als, 0.058 to 0.060 weight percent of S, 40 to 60ppm of N and 5 to 18ppm of free oxygen;
vacuum treatment of RH furnace, and circulating current N is used in the whole process of the RH furnace for molten steel 2 The gas circulation is carried out, wherein, after molten steel enters an RH furnace, vacuum pumping is carried out for 10pa-60pa for 8min-15min in 2min-5min, then vacuum degree is adjusted to 5000pa-6000pa for 12min-15min, and then the pressure is increased to atmospheric pressure, and the N content of the molten steel is 60ppm-80ppm;
and in the continuous casting process, the superheat degree of the molten steel in the tundish is 32-42 ℃ during the whole casting period of the molten steel, argon is blown from a continuous casting stopper rod, and the argon blowing flow is 1NL/min-10NL/min.
In the converter smelting step, the free oxygen content of the converter end point is controlled to be less than or equal to 350ppm, peroxidation is prevented, the determination of the addition amount of aluminum ingots or aluminum iron in the subsequent deoxidization step is facilitated, and the Als content of an Ar station after deoxidization is controlled. The deoxidizing step is to add proper amount of aluminium ingot or 40 aluminium iron into molten steel during tapping, and the total amount of molten steel in one furnace is 135-142t, and the added 40 aluminium iron is 170-280kg during deoxidizing.
Continuous casting tundish molten steel casting with high superheat: controlling the superheat degree of the tundish molten steel in the whole pouring period of each furnace molten steel to be 32-42 ℃, and if the superheat degree is less than or equal to 30 ℃, enriching the nodulation materials of the water gap, so that the stopper curve is obviously increased; if the degree of superheat is not less than 42 ℃, the probability of loosening, shrinkage cavity and dilution of the casting blank is increased. In the embodiment, the superheat degree of the molten steel in the tundish is 32-42 ℃ and is different from the instantaneous superheat degree of the molten steel in the tundish in the middle of the casting of a common ladle, namely, the superheat degree of the molten steel in the tundish is within the range in the whole casting period of the molten steel in the whole furnace. Argon is blown by the stopper rod, the argon blowing flow is 1NL/min-10NL/min, slight liquid level fluctuation around a water gap in the crystallizer is ensured, and no molten steel is obviously rolled and exposed.
In an alternative embodiment, the LF1 is sampled after power transmission for 5-10 min after the addition of the low-alkalinity slag is finished;
preferably, if Als of Ar station after deoxidation in the converter smelting step is less than 0.018wt%, sampling after molten steel reaches an LF furnace to confirm the Als content in the molten steel, and if Als is less than or equal to 0.016wt%, feeding an aluminum wire until the Als content is 0.020wt%; when feeding aluminum wires, the length of the aluminum wires for feeding can be estimated by increasing Als by 0.001% according to 5m aluminum wires.
Preferably, if Als of an Ar station after deoxidation in the converter smelting step is more than 0.028wt%, sampling and confirming the Als content in the molten steel after the molten steel reaches an LF furnace, if Als is more than or equal to 0.024wt%, increasing bottom blowing flow to Q before the sample LF1, wherein Q is more than or equal to 4, and the time of the bottom blowing flow is 8-14 min; in this embodiment, the bottom blowing flow rate Q is about 50Nm 3 And/h, the bottom blowing flow Q is about 40Nm in the processing process of the common steel 3 And/h, the higher bottom blowing flow is favorable for adjusting Als in the sample LF1 to be between 0.010 and 0.016 percent.
Preferably, if Als of the sample LF1 is less than or equal to 0.016wt%, adding aluminum wires until Als reaches 0.016wt%, and when aluminum wires are fed, estimating the length of the aluminum wires by increasing Als by 0.001% according to 5m aluminum wires, and subsequently, not adding any obvious aluminum-containing material (namely natural aluminum loss), controlling the production rhythm and bottom blowing, so that the LF outbound Als is more than or equal to 0.007%, and the outbound free oxygen content is 5-18ppm.
In an alternative embodiment, in the LF refining step, 350-400kg of lime is gradually added after molten steel is fed to a station for 1min, and 500-550kg of low-alkalinity slag is added within 10-15 min after lime addition is finished; after lime is added, low-alkalinity slag is added at intervals, because if the low-alkalinity slag is added too early, foam slag is not formed on one hand, and the temperature of molten steel is not easy to rise; on the other hand, the steel slag is thinner, the early deoxidation of the molten steel is insufficient, and the inclusions are more.
Preferably, 110kg-120kg of silicon carbide or ferrosilicon powder is added before the sample LF1 starts to add lime to the sample LF1, and 60kg-110kg of silicon carbide or ferrosilicon powder is gradually added into molten steel in the subsequent LF furnace refining step; specifically, when lime is added, 110kg to 120kg of silicon carbide is gradually added for diffusion deoxidation; the adding time of the subsequent silicon carbide can be adjusted according to the actual situation, for example, the adding time can be: adding 20-40kg of silicon carbide between the LF samples 1-2; adding 20-30kg of silicon carbide between the LF samples 2-3; after sample 3, 10kg of silicon carbide is added each time, and the total amount of the added silicon carbide in the whole LF process is controlled to be 170-230kg. In some cases, if the content of C is higher in the refining process of the LF furnace, when the control range of C is out of the risk, silicon carbide can be replaced by ferrosilicon powder for diffusion deoxidation.
Preferably, sampling is recorded as a sample A8-12 min before the molten steel of the LF station is out of the station, the S content in the sample A is more than or equal to 0.050wt%, S is supplemented to 0.058-0.060 wt% according to the sample A within 5min after the molten steel of the LF station is out of the station, and the supplementing feeding of a polysulfide wire after the RH repression is prevented.
In an alternative embodiment, the time of molten steel at an LF station is less than or equal to 100min, ar gas bottom blowing smelting is adopted in the whole LF furnace, N-containing alloy is not added in the whole LF furnace, so that the molten steel is naturally increased in N, and the content of the N at the outlet of the LF molten steel is 40-60ppm.
In an alternative embodiment, taking a steel sample from the molten steel to an RH station, marking the steel sample as a sample RH1, adding aluminum particles to increase the Als content to 0.023wt% when the vacuum degree reaches 10pa-60pa and 2min-3min after the vacuum degree reaches 10pa-60pa, and adding ferrotitanium to increase the Ti content to 0.016wt% when the vacuum degree reaches 6min-10min after the vacuum degree reaches 10pa-60 pa. In general, the amounts of aluminum particles and ferrotitanium added can be estimated by adding 0.001% of aluminum to 2kg of aluminum particles and 0.001% of Ti0.5 kg of ferrotitanium to 2kg of ferrotitanium.
In an alternative embodiment, the sample is recorded as sample RH 24 min-6min prior to RH repression; after the RH furnace is repressed, feeding Mn-N lines, wherein the feeding quantity of the Mn-N lines is 200 m/furnace-250 m/furnace; feeding Ca wires, wherein the feeding quantity of the Ca wires is 60 m/furnace-80 m/furnace, the feeding speed of the Ca wires is 250m/min-300m/min, and the interval between the Ca wires and the front feeding wires is 3.8min-4.2min; the precursor feeding line can be Mn-N line, sulfur line or Al line, and the Mn-N line feeding quantity can be estimated according to the Mn0.01% increase of 50mMn-N line in general. Since the waiting time is long, the slag surface is liable to be encrusted, and the Ca wire is liable to be fed into the molten steel, the speed of feeding the Ca wire in the present embodiment is relatively large.
Preferably, the carbonized rice husk is added for protection to prevent molten steel oxidation after Mn-N line feeding is more than or equal to 28kg, and 4 bags of carbonized rice husk are added for 7kg per bag in a manual adding mode under normal conditions.
Preferably, soft blowing is started after Ca wire feeding is completed, and the soft blowing time is 20 min/furnace-30 min/furnace.
In an alternative embodiment, if S is less than 0.055wt% in sample RH2, the sulfur line is fed 0.8min-1.2min after Mn-N line feed until S content increases to 0.055wt%, and the sulfur line parameters are: the weight of the core powder is 195g/m-205g/m, and S in the core powder is more than or equal to 99wt%; in general, the S-line feed amount can be estimated by increasing S by 0.001% according to the S-line 11 m.
In an alternative embodiment, if Als in sample RH2 is less than 0.017wt%, then feeding Al wire 1.8min-2.2min after feeding S wire to increase Als content to 0.017wt%, and if S wire is not fed, feeding Al wire 1.8min-2.2min after feeding Mn-N wire to increase Als content to 0.017wt%; the calcium line is fed after the S line is fed.
In this embodiment, after the RH is re-pressed, mn-N wire, sulfur wire, al wire, and Ca wire are sequentially fed in the relative order, where Mn-N wire, ca wire are fed, sulfur wire, and Al wire are optionally fed, where Mn-N wire is fed about 1min after the completion of Mn-N wire, al wire is fed about 2min after the completion of Mn wire, ca wire is fed about 4min after the completion of Al wire, and if any wire is not fed, the process is performed according to the longest interval time therebetween.
In an alternative embodiment, a high temperature region of 15-25 min exists after LF1 sampling, the temperature of the high temperature region is 1640-1660 ℃, so that the ladle fully absorbs heat, and the superheat degree of the molten steel in the tundish is 32-42 ℃ in the whole pouring period of the molten steel;
in an alternative embodiment, the topping furnace RH to station temperature is 1630 ℃ to 1635 ℃ and the RH to station temperature is 1553 ℃ to 1558 ℃; and/or the RH arrival temperature of the casting continuous casting furnace is 1626-1631 ℃ and the RH outbound temperature is 1548-1553 ℃.
According to the characteristics of steel components, actual requirements of the superheat degree of the molten steel in the tundish and the like, the application designs the RH, LF, ar station and converter molten steel treatment processes reversely, so that the final slag of the LF furnace is low-alkalinity slag and is stable, and the yield of S is abnormally low if a high-alkalinity and high-temperature method is adopted in the corresponding LF process; meanwhile, the application reduces the Al which is not removed in the steel under the condition of ensuring that the deoxidation of the molten steel is not poor 2 O 3 Thereby reducing nozzle clogging; in addition, the tundish stopper rod adopts an argon blowing method, so that inclusions in the tundish molten steel can be removed to the maximum extent, nozzle knots are reduced, and the number of continuous casting furnaces is ensuredAnd casting blank quality. The scheme of the application can realize continuous casting of the cast-in-situ secondary 8-furnace, has less nozzle nodulation, stable continuous casting tundish stopper curve and no obvious rising/fluctuation; the full-section flaw detection qualification rate of the final rolled material can reach more than 99 percent. In the application, the following components are added:
1. dynamically feeding aluminum wires according to the Als content of an Ar station before LF sampling 1, so as to ensure that molten steel is fully deoxidized before LF sampling 1 and the Als content is obtained during sampling 1;
2. the middle and later stages of LF refining adopt a weak deoxidation process to obtain a stable final slag system;
3. and carrying out vacuum treatment on Al and Ti in an RH furnace, wherein the adding time and the adding amount of the Al and the Ti are carried out.
4. The control of the feeding sequence, the interval time and the wire supplementing quantity after RH repression is beneficial to ensuring that the Als of the finished product is about 0.010 percent and reducing Al 2 O 3 Inclusions lead to the probability of nozzle nodulation.
5. The continuous casting tundish is poured by using a high superheat degree, which is beneficial to reducing the nodulation of the water gap and simultaneously avoiding the quality problem of casting blanks.
6. And the method for blowing argon at the water gap of the tundish is matched to remove inclusions in the molten steel of the tundish, thereby being beneficial to reducing water gap nodulation and improving casting blank quality.
Another embodiment of the present application provides a high sulfur low aluminum nitrogen containing steel having a liquidus temperature of about 1483-1485℃, comprising 0.39wt% to 0.41wt% C, 0.67wt% to 0.73wt% Si, 0.50wt% to 0.60wt% S, 1.44wt% Mn, 0.013wt% to 0.017wt% Ti, 0.09wt% to 0.017wt% Als, 90ppm to 150ppm N and less than or equal to 2ppm H.
The features and capabilities of the present application are described in further detail below in connection with the examples.
Examples
The embodiment provides a production method of high-sulfur low-aluminum nitrogen-containing steel, which comprises the following steps:
78881, pouring 2 nd 402182 th furnace, and smelting in a converter: the end point C of the converter is 0.15%, the free oxygen content is 168ppm measured by TSO, the temperature is 1606 ℃, 40 aluminum iron 177kg is added in tapping, the tapping water quantity is 137t, and the Als content of Ar station is 0.026%.
LF smelting: after molten steel reaches an LF furnace, bottom blowing is adjusted to 40Nm 3 Power transmission is started after/hGradually adding 360kg of lime into molten steel after 1min, after 2min, completely adding 80kg of silicon carbide by hand, continuously feeding 10min, gradually adding 520kg of low-alkalinity slag after 3min, manually feeding 40kg of silicon carbide, continuously feeding power for 6min, measuring the temperature to 1580 ℃, and taking an LF sample 1; LF-like 1Als0.016% and S0.010%;
after waiting for 3min, continuing to transmit power, adding 165kg of ferrosulfur alloy and other element alloys, adding 30kg of silicon carbide slag surface for deoxidization, measuring the temperature to 1650 ℃ after 20min of total power transmission, and taking an LF sample 2; LF-like 2Als0.012%, S0.049%;
after waiting for 3min, continuing to transmit power, adding 40kg of ferrosulfur alloy and other element alloys, adding 20kg of silicon carbide slag surface for deoxidization, measuring the temperature to 1655 ℃ after 15min of total power transmission, and taking an LF sample 3; LF sample 3Als0.010%, S0.056%;
after waiting for 6min, continuing to transmit power, adding other element alloys, adding 10kg of silicon carbide slag surface for deoxidization, after transmitting power for 3min, adding a sulfur iron wire 45m, continuing to transmit power for 1min, stopping power, measuring the temperature to 1645 ℃, determining the oxygen for 13ppm, taking an LF sample 4 (outbound steel sample), taking out a standing gas sample and sticking outbound slag (final slag); LF-like 4Als0.008%, S0.060%; LF gas sample N was 48ppm; LF final slag component CaO46%, siO 2 25％、Al 2 O 3 15％、TFe+MnO＝2.1wt％、MgO7％。
RH treatment: the temperature of molten steel is measured at 1631 ℃ after the molten steel arrives at a station, RH steel sample 1 (the components are obtained after 2min, RH sample 1A ls0.007%, S0.057% and Ti 0.0013%) is lifted, a ladle is lifted, an RH vacuum furnace starts pumping air, high vacuum is reached at 10-60pa after 4min, aluminum particles are added at 32kg according to the content of Als of the sample 1 (according to the target Als 0.023%), after 4min, 70 ferrotitanium is added at 37kg (according to the target Ti0.016%) and after 8min, pumping is carried out, and the pressure in the RH furnace is 5000pa-6000pa.
And after the continuous treatment is carried out for 10min, taking an RH steel sample 2 and a gas sample (the components are obtained after 2min, the RH sample 2Als is 0.013%, the S is 0.054%, the Ti is 0.015% and the N is 71 ppm), carrying out the continuous treatment for 3min, carrying out the repressing, recovering the pressure in the RH furnace to the atmospheric pressure, and measuring the temperature to 1580 ℃.
The ladle car drives into a wire feeding position, according to the RH-like 2 component, mn-N wires are fed for 200m, S wires are fed for 11m after 1min interval, al wires are fed for 20m after 2min interval, 4 bags of carbonized rice hulls are manually fed after the feeding is finished, after waiting for 4min, ca wires are fed for 60m, the temperature is measured for 1565 ℃ after the feeding is finished, soft blowing is started, after 25min of soft blowing, the temperature is measured for 1553 ℃, the RH station is used for continuous casting, and the superheat degree of ladle molten steel in the whole casting period is gradually reduced from 40 ℃ to 35 ℃.
The high sulfur low aluminum nitrogen containing steel obtained in this example had a liquidus temperature of about 1484℃, a composition of C0.40%, si 0.70%, S0.52%, mn 1.42%, ti 0.014%, als 0.011%, N118 ppm and H1.89ppm.
Comparative example 1
This comparative example provides a method for producing a high sulfur low aluminum nitrogen containing steel differing from example 1 only in that: the addition timing of the low-alkalinity slag is different (the addition timing is early), specifically:
after molten steel reaches an LF furnace, bottom blowing is adjusted to 40Nm 3 After/h, power transmission is started, after 1min, 360kg of lime is gradually added into molten steel, after 2min, 80kg of silicon carbide is manually added, immediately, 520kg of low-alkalinity slag is gradually added, after 3min, 40kg of silicon carbide is manually added, power transmission is continued for 16min, temperature measurement is carried out at 1570 ℃, and L F sample 1 is taken; LF-like 1Als0.013%, S0.012%;
because the adding time of the low-alkalinity slag is too early, the submerged arc heating time of the foam slag generated in the early stage of LF is shortened, the heating rate is slowed under the condition of consistent power transmission and time, the measured temperature in the LF sample 1 is 1570 ℃ (1580 ℃ originally), and meanwhile, the Als consumption is more (same as SiO in the slag) 2 Reaction), the desulfurization rate becomes low, indicating that the deoxidization rate is slightly inferior to that before.
Comparative example 2
This comparative example provides a method for producing a high sulfur low aluminum nitrogen containing steel, which differs from example 1 mainly in that: the adding time of the low-alkalinity slag is different (the adding time is late), specifically:
smelting in a converter: due to control fluctuation, the endpoint C is 0.25 percent higher, the TSO measures that the free oxygen content is 168ppm (the actual situation is possibly inaccurate), and the 40 aluminum iron is still added for 177kg deoxidization, so that the Als0.037% of the Ar station is abnormally high, and the follow-up treatment measures of large argon stirring abnormality in the early stage of the LF furnace are adopted;
after molten steel reaches an LF furnace, bottom blowing is adjusted55Nm of 3 After/h, power transmission is started, after 1min, 360kg of lime is gradually added into molten steel, after 2min, 80kg of silicon carbide is manually added, after 3min, 40k g silicon carbide is manually added, after 16min of power transmission is continuously carried out, the temperature is measured to 1588 ℃, and an LF sample 1 is taken; LF-like 1Als0.030%, S0.005%;
after waiting for 3min, continuing power transmission, gradually adding 520kg of low-alkalinity slag, 165kg of ferrosulfur alloy and other element alloys, adding 30kg of silicon carbide slag for surface deoxidation, measuring the temperature to 1645 ℃ after 20min of total power transmission, and taking an LF sample 2; l F sample 2Als0.020%, S0.028%;
because the Ar station Als is abnormally high and the low alkalinity slag is added too late (after LF sample 1), although the measured temperature is higher 1588 ℃ (originally 1580 ℃) when LF sample 1 is taken, LF sample 1als0.030% is still very high, resulting in abnormally low yields of ferrosulfur alloy after sample 1 (LF sample 2S originally 10+165/3.3-11=49, i.e., 0.049%, and now 5+165/3.3-27=28, i.e., 0.028%), normally 0.011% of S is lost, and now 0.027% of S is lost.
Comparative example 3
This comparative example provides a method for producing a high sulfur low aluminum nitrogen containing steel differing from example 1 only in that: the adding time of the RH furnace Al and Ti is different (the adding time is earlier), specifically:
RH treatment: the temperature of molten steel is measured at 1631 ℃ after the molten steel arrives at a station, RH steel sample 1 (the components are obtained after 2min, RH sample 1A ls0.007%, S0.057% and Ti 0.0013%), a ladle is lifted, an RH vacuum furnace starts pumping air, high vacuum is reached at 10-60pa after 4min, aluminum particles are added at 32kg when pumping air for 3min (the high vacuum is not reached at the moment), 70 ferrotitanium is added at 37kg after 4min (according to the target Ti 0.016%), and pumping is carried out after 11min, so that the pressure in the RH furnace is 5000pa-6000pa.
And after the continuous treatment is carried out for 10min, taking an RH steel sample 2 and a gas sample (the components are obtained after 2min, the RH sample 2Als is 0.008%, the S is 0.054%, the Ti is 0.013% and the N is 69 ppm), carrying out the continuous treatment for 3min, carrying out the repressing, recovering the pressure in the RH furnace to the atmospheric pressure, and measuring the temperature to 1579 ℃.
Because the adding time of aluminum particles and ferrotitanium is early, steel slag still circulates in molten steel in an RH air extraction stage and does not float to the slag surface in time, the added aluminum particles are quickly oxidized by the steel slag with stronger oxidability to be lost, and meanwhile, because the adding time of ferrotitanium is also early, ti is also partially oxidized; the Al wires which need to be fed are more after the subsequent repressing, in addition, ferrotitanium can be fed only by hand (not molten steel is added in RH high vacuum) after the repressing, so that the influence on the cleanliness of the molten steel is great, and a stopper rod rises during the casting of the molten steel.
Comparative example 4
This comparative example provides a method for producing a high sulfur low aluminum nitrogen containing steel differing from example 1 only in that: the RH furnace has different addition amounts of Al and Ti (more aluminum particles are added), and specifically:
in order to avoid feeding aluminum wires after repressing, more aluminum particles are added in the earlier stage of RH.
RH treatment: the temperature of molten steel is measured at 1631 ℃ after reaching a station, RH steel sample 1 (the components are obtained after 2min, RH sample 1A ls0.007%, S0.057% and Ti 0.0013%) is lifted, a ladle is lifted, an RH vacuum furnace starts pumping, high vacuum is reached at 10-60pa after 4min, 40kg of aluminum particles (added according to the content of Als of sample 1 (0.027% and 0.023%) is added after 2min, 70 ferrotitanium 37kg (added according to the content of Ti 0.016%) is added after 4min, and the pressure in the RH furnace is 5000pa-6000pa after 8 min.
And (3) continuously treating for 10min, taking an RH steel sample 2 and a gas sample (the components of the RH sample 2Als0.022%, S0.054%, ti0.0155% and N70ppm are obtained after 2 min), continuously treating for 3min, re-pressing, recovering the pressure in the RH furnace to the atmospheric pressure, and measuring the temperature to 1580 ℃.
Theoretically, the RH-like 2Als should be 0.017%, but because the furnace is a non-pouring-time 2 furnace, the RH vacuum tank aluminum loss may be smaller, so that the aluminum loss is only 0.005% (originally 0.023% to 0.013%), therefore, the furnace finished Als is higher than 0.016%, and the stopper curve rises more during molten steel pouring, which means that the immersed nozzle has more nodules.
Comparative example 5
This comparative example provides a method for producing a high sulfur low aluminum nitrogen containing steel differing from example 1 only in that: the feeding line spacing time is different after RH repression, specifically:
and after the continuous treatment is carried out for 10min, taking an RH steel sample 2 and a gas sample (the components are obtained after 2min, the RH sample 2Als is 0.013%, the S is 0.054%, the Ti is 0.015% and the N is 71 ppm), carrying out the continuous treatment for 3min, carrying out the repressing, recovering the pressure in the RH furnace to the atmospheric pressure, and measuring the temperature to 1580 ℃.
The ladle car drives into the wire feeding position, according to RH appearance 2 composition, begin to feed Mn-N200 m, but M N-N broken wire when feeding 150m, after 6min of treatment, the feed is the remaining 50mMn-N wire, after 1min interval, feed S line 11m, after 2min of feeding Al line 20m, after feeding, hand 4 bags of carbonization rice hulls, because the aforesaid process broken wire time leads to production tight rhythm, after hand is thrown carbonization rice hulls, immediately feed Ca line 60m, after finishing feeding, temperature measurement 1564 ℃, begin soft blowing, after 23min of soft blowing, temperature measurement 1552 ℃, go out of RH station and go to continuous casting pouring.
Since Al in the wire is not completely uniform in molten steel after the Al wire is fed, partial high-concentration clusters exist, and after Ca wire is fed, the Al wire is combined with Ca to form non-12 CaO.7Al 2 O 3 The liquid inclusions are difficult to remove, and the stopper rod rises when the molten steel is poured in the furnace.
Comparative example 6
This comparative example provides a method for producing a high sulfur low aluminum nitrogen-containing steel, which differs from example 1 mainly in that: the feeding and supplementing amounts are different after RH repression, and specifically:
because of LF control problem, RH is higher to the station molten steel temperature, which is 1641 ℃, and RH is treated normally before.
After the pump is removed, the RH steel sample 2 and the gas sample (the components are obtained after 2 min), the RH sample 2Al S0.013%, S0.054%, ti0.015% and N71 ppm) are continuously treated for 10min, the pressure in the RH furnace is recovered to the atmospheric pressure, and the temperature is measured to 1590 ℃ (the original temperature is 1580 ℃).
The ladle car drives into a wire feeding position, according to the RH-like 2 component, mn-N wires are fed for 200m, S wires are fed for 33m (11 m originally) after 1min interval, al wires are fed for 50m (20 m originally) after 2min interval, 4 bags of carbonized rice hulls are fed by hand after the feeding is finished, after waiting for 4min, ca wires are fed for 60m, the temperature is measured for 1574 ℃ after the feeding is finished, soft blowing (the soft blowing period is larger, the temperature is reduced in the period of time), after the soft blowing is carried out for 25min, the temperature is measured for 1553 ℃, and the ladle car is discharged from an RH station for continuous casting and pouring.
The final finished products Als0.015 percent and S0.053 percent, although the outlet temperature of molten steel RH is reduced to a proper temperature, more Al lines and S lines are also supplemented in advance to prevent larger soft blowing and more loss, the stopper rod rises when the molten steel of the furnace is poured due to too much supplementary feeding of the Al lines and higher actual finished products Als.
Comparative example 7
This comparative example provides a method for producing a high sulfur low aluminum nitrogen containing steel differing from example 1 only in that: the continuous casting tundish does not use higher superheat degree pouring (uses lower superheat degree), and specifically:
because of LF control problems, RH is lower to the station molten steel temperature of 1621 ℃ and RH is treated normally before.
After the pump is removed, the RH steel sample 2 and the gas sample (the components are obtained after 2 min), the RH sample 2Al S0.013%, S0.054%, ti0.015% and N71 ppm) are continuously treated for 10min, the pressure in the RH furnace is recovered to the atmospheric pressure, and the temperature is measured to 1570 ℃ (originally 1580 ℃).
The ladle car drives into the wire feeding position, according to RH appearance 2 composition, feed Mn-N line 200m, after 1min interval, feed S line 11m, after 2min, feed Al line 10m, after finishing feeding, hand throw 4 bags of carbonized rice husk, after waiting for 4min, feed Ca line 60m, after finishing feeding temperature measurement 1555 ℃, begin soft blowing, after soft blowing 25min, temperature measurement 1543 ℃, go out RH station and go out continuous casting pouring, tundish molten steel superheat degree gradually reduces from 32 ℃ to 26 ℃ during the whole pouring period, because the superheat degree is low, endogenous inclusions are easier to be separated out, and stopper curve rises obviously during molten steel pouring.
Comparative example 8
This comparative example provides a method for producing a high sulfur low aluminum nitrogen containing steel differing from example 1 only in that: the continuous casting tundish does not use high superheat degree pouring (uses high superheat degree), and specifically:
because of LF control problem, RH is higher to the station molten steel temperature, which is 1642 ℃, and RH is treated normally before.
After the pump is removed, the RH steel sample 2 and the gas sample (the components are obtained after 2 min), the RH sample 2Al S0.013%, S0.054%, ti0.015% and N71 ppm) are continuously treated for 10min, the pressure in the RH furnace is recovered to the atmospheric pressure, and the temperature is measured to 1591 ℃ (the original temperature is 1580 ℃).
The ladle car drives into a wire feeding position, according to the RH-like 2 component, mn-N wire 200m is fed, S wire 11m is fed after 1min interval, al wire 10m is fed after 2min interval, 4 bags of carbonized rice hulls are manually fed after the feeding is finished, after 4min waiting, ca wire 60m is fed, the temperature is measured at 1577 ℃ after the feeding is finished, soft blowing is started, after 25min of soft blowing, the temperature is measured at 1565 ℃, the RH station is used for continuous casting and pouring, the superheat degree of tundish molten steel is gradually reduced from 49 ℃ to 44 ℃ during the whole pouring period, endogenous inclusions are not easy to separate out due to high superheat degree, and the rising of a stopper curve is not obvious when the inclusion molten steel is poured.
However, due to high-superheat casting, casting blank center segregation and looseness are serious, and the number of unqualified round blanks for flaw detection in the center of a rolled material is too large.
Comparative example 9
This comparative example provides a method for producing a high sulfur low aluminum nitrogen containing steel differing from example 1 only in that: the continuous casting tundish does not use a stopper rod to blow argon, specifically:
the stopper rod is tested without argon blowing in the last casting time, when molten steel and steel in the furnace are cast, the flow of argon is closed, and after 1min, the curve of the stopper rod is obviously increased.
Fluctuation in amplitude of mm on stopper rod Flaw detection qualification rate of rolled material%
Examples 0.52 99.27
Comparative example 1 0.89 98.55
Comparative example 2 1.1 98.31
Comparative example 3 4.4 97.57
Comparative example 4 3.7 98.06
Comparative example 5 2.4 98.07
Comparative example 6 3.5 98.06
Comparative example 7 5.1 97.09
Comparative example 8 0.6 97.33
Comparative example 9 2.3 97.83
The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims (10)

1. A method for producing a high sulfur low aluminum nitrogen containing steel, comprising:
converter smelting, wherein the free oxygen content at the end point of the converter is controlled to be less than or equal to 350ppm, then tapping is carried out, deoxidizing is carried out during tapping, and the Als of an Ar station after deoxidizing is 0.018-0.028 wt%;
refining in an LF furnace, adding 350-400kg of lime, 500-550kg of low-alkalinity slag and 170-230kg of silicon carbide or ferrosilicon powder into 135-142t molten steel when the molten steel is in the LF furnace, and obtaining steel slag with binary alkalinity of W (CaO)/W (SiO) 2 )＝1.5-2.0、CaO 44wt％-48wt％、SiO 2 24wt％-28wt％、Al 2 O 3 14 to 18 weight percent, 1.5 to less than or equal to TFe+MnO to less than or equal to 3.0 weight percent, 4 to 9 weight percent of MgO, and the main components of the LF outbound molten steel are more than or equal to 0.007 weight percent of Als, 0.058 to w t to 0.060 weight percent of S, 40 to 60ppm of N and 5 to 18ppm of free oxygen;
vacuum treatment of RH furnace, and circulating current N is used in the whole process of the RH furnace for molten steel 2 The gas circulation is carried out, wherein, after molten steel enters an RH furnace, vacuum pumping is carried out for 10pa-60pa for 8min-15min in 2min-5min, then vacuum degree is adjusted to 5000pa-6000pa for 12min-15min, and then the pressure is increased to atmospheric pressure, and the N content of the molten steel is 60ppm-80ppm;
and in the continuous casting process, the superheat degree of the molten steel in the tundish is 32-42 ℃ during the whole casting period of the molten steel, argon is blown from a continuous casting stopper rod, and the argon blowing flow is 1NL/min-10NL/min.
2. The method for producing the high-sulfur low-aluminum nitrogen-containing steel according to claim 1, wherein the power is transmitted for 5-10 min to sample LF1 after the low-alkalinity slag is added;
preferably, if Als of Ar station after deoxidation in the converter smelting step is less than 0.018wt%, sampling after molten steel reaches an LF furnace to confirm the Als content in the molten steel, and if Als is less than or equal to 0.016wt%, feeding an aluminum wire until the Als content is 0.020wt%;
preferably, if Als of an Ar station after deoxidation in the converter smelting step is more than 0.028wt%, sampling and confirming the Als content in the molten steel after the molten steel reaches an LF furnace, if Als is more than or equal to 0.024wt%, increasing bottom blowing flow to Q before the sample LF1, wherein Q is more than or equal to 4, and the time of the bottom blowing flow is 8-14 min;
preferably, if Als of the sample LF1 is less than or equal to 0.016wt%, the aluminum wire is added to an Als of 0.016wt%.
3. The method for producing high-sulfur low-aluminum nitrogen-containing steel according to claim 2, wherein in the LF furnace refining step, 350-400kg of lime is gradually added after the molten steel is fed to a station for 1min, and 500-550kg of low-alkalinity slag is added within 10-15 min after lime addition is completed;
preferably, 110kg-120kg of silicon carbide or ferrosilicon powder is added before the sample LF1 starts to add lime to the sample LF1, and 60kg-110kg of silicon carbide or ferrosilicon powder is gradually added into molten steel in the subsequent LF furnace refining step;
preferably, sampling is recorded as sample A8-12 min before the molten steel of the LF station goes out of the station, the S content in the sample A is more than or equal to 0.050wt%, and S is supplemented to reach 0.058wt% to 0.060wt% according to the sample A within 5min after the molten steel of the LF station goes out of the station.
4. The method for producing the high-sulfur low-aluminum nitrogen-containing steel according to claim 1, wherein the time of the molten steel at the LF station is less than or equal to 100min, ar gas bottom blowing smelting is adopted in the whole LF furnace, and N-containing alloy is not added in the whole LF furnace, so that the molten steel is naturally increased in N.
5. The method for producing high-sulfur low-aluminum nitrogen-containing steel according to claim 1, wherein the molten steel is sampled from an RH station and marked as sample RH1, aluminum particles are added to increase the Als content to 0.023wt% when the vacuum degree reaches 10pa-60pa and then titanium iron is added to increase the Ti content to 0.016wt% when the vacuum degree reaches 6min-10min after the vacuum degree reaches 10pa-60pa according to the Als and Ti contents in the sample RH 1.
6. The method for producing a high-sulfur low-aluminum nitrogen-containing steel according to claim 1, wherein the sample is taken as a sample RH 24 min to 6min before the RH is repressed; after the RH furnace is repressed, feeding Mn-N lines, wherein the feeding quantity of the Mn-N lines is 200 m/furnace-250 m/furnace; feeding Ca wires, wherein the feeding quantity of the Ca wires is 60 m/furnace-80 m/furnace, the feeding speed of the Ca wires is 250m/min-300m/min, and the interval between the Ca wires and the front feeding wires is 3.8min-4.2min;
preferably, the carbonized rice husk is added to be more than or equal to 28kg after the Mn-N line is fed;
preferably, soft blowing is started after Ca wire feeding is completed, and the soft blowing time is 20 min/furnace-30 min/furnace.
7. The method for producing a high sulfur low aluminum nitrogen containing steel according to claim 6, wherein if S in RH2 is less than 0.055wt%, the S content is increased to 0.055wt% by feeding sulfur line for 0.8min-1.2min after feeding Mn-N line, and the parameters of the sulfur line are: the weight of the core powder is 195g/m-205g/m, and S in the core powder is more than or equal to 99wt%;
and/or if Als in the sample RH2 is less than 0.017wt%, feeding Al wire to increase the Als content to 0.017wt% within 1.8-2.2 min after feeding the S wire, and feeding Al wire to increase the Als content to 0.017wt% within 1.8-2.2 min after feeding the Mn-N wire if the S wire is not fed; the calcium line is fed after the S line is fed.
8. The method for producing a high-sulfur low-aluminum nitrogen-containing steel according to claim 2, wherein a high temperature region of 15min-25min exists after sampling LF1, and the temperature of the high temperature region is 1640 ℃ -1660 ℃.
9. The method for producing a high sulfur low aluminum nitrogen containing steel according to claim 8, wherein the secondary topping furnace RH to station temperature is 1630-1635 ℃ and the RH to station temperature is 1553-1558 ℃; and/or the RH arrival temperature of the casting continuous casting furnace is 1626-1631 ℃ and the RH outbound temperature is 1548-1553 ℃.
10. A high sulfur low aluminum nitrogen containing steel according to any one of claims 1 to 9 wherein the liquidus temperature is 1483 ℃ to 1485 ℃ comprising C0.39 wt% to 0.41wt%, si 0.67wt% to 0.73wt%, S0.50 wt% to 0.60wt%, mn 1.36wt% to 1.44wt%, ti0.013 wt% to 0.017wt%, als 0.09wt% to 0.017wt%, N90ppm to 150ppm and H less than or equal to 2ppm.
CN202310958038.9A 2023-08-01 2023-08-01 Production method of high-sulfur low-aluminum nitrogen-containing steel Pending CN116949349A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310958038.9A CN116949349A (en) 2023-08-01 2023-08-01 Production method of high-sulfur low-aluminum nitrogen-containing steel

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310958038.9A CN116949349A (en) 2023-08-01 2023-08-01 Production method of high-sulfur low-aluminum nitrogen-containing steel

Publications (1)

Publication Number Publication Date
CN116949349A true CN116949349A (en) 2023-10-27

Family

ID=88452729

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310958038.9A Pending CN116949349A (en) 2023-08-01 2023-08-01 Production method of high-sulfur low-aluminum nitrogen-containing steel

Country Status (1)

Country Link
CN (1) CN116949349A (en)

Similar Documents

Publication Publication Date Title
CN110373600B (en) Smelting process method of high-aluminum sulfur-containing calcium-controlling steel
CN104726646B (en) A kind of method of nitrogen content in control high-temperature alloy steel P 91
CN108330245A (en) A kind of high-purity smelting process of stainless steel
CN111910045B (en) Smelting method of high-purity austenitic stainless steel
CN110144433B (en) Deoxidation slagging method of low-carbon aluminum killed steel
CN110527775B (en) RH refining furnace chemical temperature rising method suitable for low-carbon aluminum killed steel
CN110331258B (en) Production process for controlling Cr content of ultra-low carbon silicon killed steel during RH vacuum treatment
CN109402327B (en) External refining production method of ultrapure high-carbon chromium bearing steel
CN112267004A (en) Smelting method of low-cost clean steel
CN110592323A (en) Sheet billet continuous casting and rolling smelting process and RH refining deoxidation method used for same
CN103031492A (en) High-toughness steel for gas cylinders and smelting method thereof
CN112442572A (en) Deoxidation control method for high-end bearing steel inclusion
CN111663072B (en) Anti-nodulation high-sulfur non-quenched and tempered steel smelting process
CN111621621B (en) Control method of Mn in molten steel in RH vacuum treatment process
CN114058767A (en) Method for refining rare earth inclusions in super stainless steel
CN114318108A (en) Production method of ultra-low-aluminum high-purity industrial pure iron
KR20090065994A (en) A method of manufacturing austenite stainless steel
CN111041352A (en) External refining production method of wire rod for cutting diamond wire
CN108265228A (en) A kind of production method of high cutting ability steel
CN116949349A (en) Production method of high-sulfur low-aluminum nitrogen-containing steel
JP2009191290A (en) Method for producing ingot of extra-low carbon steel
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
CN111705178A (en) Method for controlling oxygen content in molten steel RH vacuum refining furnace
CN115637306B (en) Control method for B-type inclusion in high-carbon chromium bearing 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