CN113403522B - Smelting method based on alloyed ultrahigh-strength and ultrahigh-strength high-carbon hard wire steel - Google Patents

Smelting method based on alloyed ultrahigh-strength and ultrahigh-strength high-carbon hard wire steel Download PDF

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CN113403522B
CN113403522B CN202110494329.8A CN202110494329A CN113403522B CN 113403522 B CN113403522 B CN 113403522B CN 202110494329 A CN202110494329 A CN 202110494329A CN 113403522 B CN113403522 B CN 113403522B
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CN113403522A (en
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王广顺
郭洛方
高永彬
徐凯
李麦麦
陈殿清
袁相坤
刘政鹏
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Qingdao Special Steel Co ltd
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    • 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
    • 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
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/30—Regulating or controlling the blowing
    • C21C5/32—Blowing from above
    • 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
    • C21C7/0025—Adding carbon material
    • 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
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • 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
    • C21C2007/0093—Duplex process; Two stage processes
    • 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

Abstract

The invention provides a smelting method based on alloyed ultrahigh-strength and ultrahigh-strength high-carbon hard wire steel, which sequentially comprises the following steps of: the method comprises the following steps of molten iron pretreatment desulfurization, converter blowing, refining and continuous casting blank forming, wherein the converter blowing adopts duplex converter blowing, the refining adopts a steel-slag interfacial tension adjusting method, a pressure and displacement balance control method is adopted under continuous casting light pressure, and the high-carbon hard wire steel comprises the following components in percentage by weight: c: 0.84-1.2%, Si: 0.15-1.5%, Mn: 0.35-0.80%, Cr: 0.10-0.80%, P: less than or equal to 0.015%, S: less than or equal to 0.010 percent, Ni: 0.0001-0.30%, V: 0.13-0.30%, Cu: less than or equal to 0.05 percent, Al: less than or equal to 0.10 percent, N: less than or equal to 0.005 percent, and the balance of Fe and inevitable impurities. The converter duplex method is adopted for blowing, so that the alloy yield is improved, and the production cost is reduced; in the refining process, a steel-slag interfacial tension adjustment control technology is adopted, so that top slag inclusion is reduced, and the purity of the molten steel is improved; and the pressure and displacement balance control mode is adopted in the continuous casting soft reduction, so that the homogenization stability level in the casting blank is improved.

Description

Smelting method based on alloyed ultrahigh-strength and ultrahigh-strength high-carbon hard wire steel
Technical Field
The invention belongs to the technical field of steel smelting processes, and particularly relates to a smelting method of high-carbon hard wire steel based on alloying ultrahigh strength and ultrahigh strength.
Background
Along with the rapid development of automobiles, road traffic, bridge construction, ocean engineering equipment and the like in China, hard wire varieties such as steel cords for automobile tire meridian lines, bridge cable steel wires, marine steel wire ropes, prestressed steel strands and the like are also rapidly upgraded towards the direction of high reinforcement and resource conservation. The high-carbon hard wire steel is continuously developed in the directions of high reinforcement, refinement, green manufacturing and resource saving, for example, the bridge cable steel is developed to 2100MPa in the next step, so that the self weight is further reduced, and the wind resistance is reduced; the strength of the steel cord for the tire is more than 4000Mpa grade; the strength of the diamond wire exceeds 5000MPa, and the monofilament diameter can be drawn to be less than 0.05 mm. The smelting technology of high homogeneity and high purity of the high-carbon hard wire steel wire rod is the key core power for developing and upgrading high-carbon hard wire steel products. The performance improvement of the high-carbon hard wire steel grade puts severe technical requirements on the steel smelting process.
At present, Chinese steel enterprises can stably produce the wire rod for the steel cord with common strength, high strength level and a small amount of super strength, the bridge cable can reach 2000Mpa level at most, the prestressed steel strand is still maintained at 1860Mpa level, products with higher strength still mainly depend on import, and the import place is mainly countries and regions such as Japan, Korea, European Union and the like. In order to realize the localization of the ultrahigh-strength and ultrahigh-strength high-carbon hard wire steel, the smelting level of the ultrahigh-strength and ultrahigh-strength high-carbon hard wire steel is more challenging.
In order to realize the stable smelting production of the ultrahigh-strength and ultrahigh-strength high-carbon hard wire steel, the smelting process of the ultrahigh-strength and ultrahigh-strength high-carbon hard wire steel needs to be innovated and optimized, and the technical problems of precise control of alloying components, control of inclusions in steel, control of central carbon segregation and the like are overcome.
Patent document CN107794332A, a method for smelting 90-grade ultrahigh-strength cord steel: the smelting method of the 90-grade ultrahigh-strength cord steel comprises the working procedure operation key points of converter smelting, LF refining, continuous casting protection pouring and the like. The patent provides a smelting method aiming at component control, slag charge control, protective pouring and continuous casting of each process of 90-grade cord steel, is not suitable for smelting based on alloyed ultrahigh-strength and ultrahigh-strength hard wire steel, and does not relate to the technical problem of segregation control of carbon and alloy elements.
Patent document CN103060513A, a method of smelting a cord steel and a method of continuously casting a cord steel: provides a process flow of 'converter primary smelting, vacuum refining, ladle furnace refining and bloom continuous casting pouring' for producing the cord steel, and realizes the clean production of the cord steel. The patent mainly proposes the control of components and molten steel cleanliness in the working procedures of converter, vacuum refining, ladle refining and the like, and does not relate to the segregation control of carbon and alloy elements. The alloying high-carbon hard wire steel can be smelted without adopting the process flow, and the high cleanliness of the smelting of the high-strength hard wire steel grade is also realized.
Patent document CN201510437468.1 discloses a method for producing high strength steel wire rod for bridge cable, which includes controlling the process parameters of the continuous casting and rolling processes, but does not mention the control methods of high homogenization and high cleanliness.
Patent document CN201610790875.5 discloses a method for smelting high-strength steel by vanadium-nitrogen microalloying, which proposes a method for smelting steel by adding vanadium-nitrogen microalloying steel in the steps of tapping from a blast furnace, smelting in a converter, blowing argon, continuous casting, rolling steel and the like. However, unlike this patent, the alloying of this patent mainly uses the addition of silicon (Si), chromium (Cr), nickel (Ni), vanadium (V) and other alloying elements, and this patent does not mention the segregation control of carbon and alloying elements and the steel purity control technology.
Disclosure of Invention
The invention provides a smelting method of high-carbon hard wire steel based on alloying ultrahigh strength and ultrahigh strength, which solves the technical problems of precise control of alloying components, control of inclusions in steel, control of central carbon segregation and the like in the prior art.
The invention provides a smelting method based on alloyed ultrahigh-strength and ultrahigh-strength high-carbon hard wire steel, which sequentially comprises the following steps of: the method comprises the following steps of molten iron pretreatment desulfurization, converter blowing, refining and continuous casting blank forming, wherein the converter blowing adopts duplex converter blowing, the refining adopts a steel-slag interfacial tension adjusting method, the continuous casting is carried out under a light pressure by adopting a pressure and displacement balance control method, and the high-carbon hard wire steel comprises the following components in percentage by weight: c: 0.84-1.2%, Si: 0.15-1.5%, Mn: 0.15-0.80%, Cr: 0.10-0.80%, P: less than or equal to 0.015%, S: less than or equal to 0.010 percent, Ni: 0.0001-0.30%, V: 0.0005-0.30%, Cu: less than or equal to 0.05 percent, Al: less than or equal to 0.10 percent, N: less than or equal to 0.005 percent, and the balance of Fe and inevitable impurities.
Preferably, in the step of converter blowing, the lance position is controlled to 1100-1300mm during the dephosphorization, and the oxygen flow is 7000-12000m3And h, after the lance is lifted up when the blowing is finished, waiting for 1 minute in a zero position state, and then shaking the furnace to dump slag.
Preferably, the basicity R of the converter of the dephosphorizing furnace is controlled to be 1.9-2.3, the tapping temperature of the semisteel is controlled to be 1300-3/t。
Preferably, in the step of converter blowing, the decarburization furnace is added into a semi-molten steel whole furnace without adding scrap steel, the ignition gun position of the decarburization furnace is 1500-3And h, increasing oxygen supply amount of the oxygen lance by adopting a manual step method after ignition for one minute, and gradually reducing oxygen blowing flow in the later smelting period.
Preferably, the alkalinity R of the converter of the decarburization furnace is controlled to be 3.0-5.0, the tapping temperature is controlled to be more than or equal to 1605 ℃, and the tapping carbon content is controlled to be 0.20-0.30% in order to ensure the one-time success of carbon pulling.
Preferably, in the refining step, after the electricity is supplied for 5-15 minutes in the early stage of refining, the slag dissolving agent of calcium chloride is added into the top slag, and the interfacial tension of the steel slag is controlled to be 1.25-1.70N/m.
Preferably, in the continuous casting step, the initial calibration of the roll gap value is carried out on each press roller under light pressure before the continuous casting production, the first roll gap value of the withdrawal and straightening unit is set to be 184.5-185.5mm according to the outlet size of a crystallizer copper pipe and the cooling shrinkage of each high-carbon steel type, the pressure difference of an upper roll and a lower roll is stabilized to be 0.9-1.5Mpa during the calibration, and the calibration error value of each roll gap value is less than or equal to 0.5 mm.
Preferably, establishing a soft reduction standard pressure value of each steel type of each roller, if the actual tension value is lower than the standard value by 0.1-0.5Mpa, increasing the actual reduction by 0.2mm in the displacement mode, otherwise, decreasing the actual reduction by 0.2 mm.
The invention has the beneficial effects that:
the converter duplex method high-efficiency alloying smelting method of silicon (Si), chromium (Cr), nickel (Ni) and vanadium (V) is innovatively implemented, the alloy yield is improved, and the production cost is reduced;
in the refining process, a steel-slag interfacial tension adjustment control technology is adopted, so that top slag inclusion is reduced, and the purity of the molten steel is improved;
and the pressure and displacement balance control mode is adopted in the continuous casting soft reduction, so that the homogenization stability level in the casting blank is improved.
Drawings
FIG. 1 is a C segregation index distribution diagram of 1C97D2Cr cord steel in example 1 of the present invention,
FIG. 2 is a graph showing the results of ASPEX scanning electron microscope inclusion analysis of 2QS92Si hard wire steel in example 2 of the present invention,
FIG. 3 is a C segregation index distribution diagram of 2QS92Si hard wire steel in example 2 of the present invention,
FIG. 4 is a graph showing the results of ASPEX scanning electron microscope inclusion analysis of QS87MnSi high carbon steel in example 3 of the present invention,
FIG. 5 is a C segregation index distribution diagram of QS87MnSi high carbon steel in example 3 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and should not be construed as limiting the scope of the invention.
Example 1
Selecting a furnace of steel for producing the C97D2Cr cord steel, wherein the steel comprises the following components in percentage by weight: c: 0.97%, Si: 0.20%, Mn: 0.35%, Cr: 0.10%, P: 0.010%, S: 0.005%, Ni: 0.0001%, V: 0.0005%, Cu: 0.04%, Al: 0.003%, N: 0.004%, and the balance of Fe and inevitable impurities. The smelting method sequentially comprises the steps of molten iron pretreatment and desulfurization, converter blowing, refining and continuous casting to form a blank. The molten iron pretreatment desulfurization adopts KR desulfurization or granular magnesium desulfurization, the refining adopts LF refining and RH vacuum refining, and the continuous casting is 150mm-240mm square billet or rectangular billet casting. Specifically, a duplex converter is adopted for blowing, so that the alloy yield is improved.
(1) In order to improve the dephosphorization capability and reduce the smelting cost, the lance position is controlled to be 1200mm when the dephosphorization furnace blows, and the oxygen supply flow is 9000m3H; after blowing is finished, the lance is lifted and waits for 1 minute in a zero position state, and then the furnace is shaken to remove slag.
(2) Controlling the basicity R of a converter of the dephosphorizing furnace to be 2.0, controlling the tapping temperature of semisteel to be 1350 ℃, and adding 300kg of carburant in the tapping process of the dephosphorizing furnace; the oxygen consumption of the dephosphorizing furnace is controlled to be 11.2m3And t, reaching the advanced level of oxygen consumption control of duplex converters at home and abroad.
(3) In order to ensure heat balance, the decarburization furnace is added with a semi-molten steel full furnace without adding scrap steel; the ignition gun position of the decarburization furnace is 1550mm, and the ignition flow is 10000m3And h, increasing oxygen supply amount of the oxygen lance by adopting a manual step method after one minute, and gradually reducing oxygen blowing flow in the later smelting period.
(4) The basicity R of the converter of the decarburization furnace is controlled to be 3.5, the tapping temperature is controlled to be 1613 ℃, the carbon drawing is successful once, the tapping carbon content is controlled to be 0.25%, the oxygen content can be controlled to be lower, and a superior thermodynamic condition is created for improving the alloy yield.
(5) 230kg of silicon carbide and 200k of aluminum-containing top slag are added 1 minute before tapping; after strong stirring (the blowing valve at the bottom of the ladle is opened to the maximum) for 1 minute, the low-nitrogen carburant is added, and the carbon distribution target is 0.90% after the furnace; then, the mixture is stirred strongly for 1 minute, and then alloy such as ferrosilicon, ferromanganese, ferrochrome, ferrovanadium, ferronickel and the like is added.
(6) Through calculation, the recovery rate of carbon in the steel converter reaches 93%, the yield of Si alloy reaches 92%, the yield of Mn, Cr and Ni alloy reaches 99.89%, the alloy consumption is greatly reduced, and the smelting cost is reduced.
And a steel-slag interfacial tension adjusting method is adopted in the refining process, so that top slag inclusion is reduced, and the purity of the molten steel is improved. In the refining process, reactions occur at phase interfaces between slag-gas, steel-gas and slag-steel, surface tension and interfacial tension are important thermodynamic properties of the phase interfaces, and the wetting condition of the steel slag, namely the separation difficulty of the mixed steel slag, is determined in the actual smelting process.
Slag entrapment occurs in the refining process, and the slag entrapped has attraction among all phase interfaces of slag, steel and the like in molten steel, which is called adhesive force (also called adhesive force); the work done during the separation of the two phases is called adhesion work (also called sticking work), which is expressed by WAttached withOr WAExpressed (e.g., 1 unit per unit area) the formula is:
Wattached with=σSteel-gas+σSlag-gas-σSteel-slag (1)
In the formula, σSteel-gas-surface tension of the molten steel; sigmaSlag-gas-surface tension of the slag; sigmaSteel-slag-interfacial tension of the steel slag.
WAttached withThe larger the value is, the larger the adhesion (attraction) force of steel and slag is, and the separation is difficult; wAttached withWhen the content is 0, the steel slag is completely immiscible liquid, namely, the steel slag is most easily separated under ideal conditions.
In order to reduce the top slag involved in the refining process and improve the purity of the molten steel, the patent provides a steel slag interfacial tension adjustment smelting technology, reduces the surface tension of slag particles and simultaneously increases the steel slag interfacial tension smelting technology, and specifically, (7) after power is supplied for 8 minutes in the early stage of refining, 120kg of a calcium chloride slagging agent is added into the top slag, and the steel slag interfacial tension is controlled at 1.32N/m.
And a pressure and displacement balance control method is adopted in continuous casting soft reduction, so that the homogenization stability level in the casting blank is improved.
Continuous casting soft reduction is an important technical means for controlling segregation of high-carbon steel, but the stability control difficulty of segregation of high-carbon high-alloy steel under soft reduction is high, and the stability of segregation control under soft reduction is effectively improved by adopting a pressure and displacement balance control method through theoretical analysis and production practice. In particular, the method comprises the following steps of,
(8) the method comprises the steps of carrying out initial calibration on roll gap values of the press rolls under soft pressing before continuous casting production, setting the first roll gap value of the withdrawal and straightening unit to be 185.0mm, stabilizing the pressure difference between the upper roll and the lower roll to be 1.0Mpa during calibration, and setting the calibration error value of each roll gap value to be less than or equal to 0.3 mm.
(9) And increasing the actual pressing amount in the displacement mode by 0.2mm when the actual tension value of the 3 rd and 4 th pairs of rollers of each flow is lower than the standard value of 0.2-0.3 Mpa.
(10) After 24 samples are taken for detection, the maximum size of the inclusions is less than or equal to 15 mu m, and the maximum segregation index of the semi-finished product 1# shear sample is 1.04.
Table-results of the measurement of the size of inclusions
Figure GDA0003193760820000051
Referring to fig. 1, the C segregation index of the semi-finished product 1# shear sample reaches a level less than or equal to 1.04, and from the detection result, the distribution uniformity of the C element is better, and a higher control level is reached.
Example 2
Selecting a furnace of steel for producing QS92Si steel, wherein the steel comprises the following components in percentage by weight: c: 0.92%, Si: 0.95%, Mn: 0.55%, Cr: 0.37%, P: 0.008%, S: 0.002%, Ni: 0.0001%, V: 0.0005%, Cu: 0.04%, Al: 0.032%, N: 0.003% and the balance of Fe and inevitable impurities. The specific implementation process is as follows:
(1) the lance position is controlled to 1290mm when the dephosphorization furnace blows, and the oxygen supply flow is 9200m3H; after blowing is finished, the lance is lifted and waits for 1 minute in a zero position state, and then the furnace is shaken to remove slag.
(2) Controlling the basicity R of a converter of the dephosphorization furnace to be 2.0, controlling the tapping temperature of semisteel to be 1389 ℃, and adding 350kg of carburant in the tapping process of the dephosphorization furnace; the oxygen consumption of the dephosphorizing furnace is controlled to be 11.56m3And t, reaching the advanced level of oxygen consumption control of duplex converters at home and abroad.
(3) Adding a semi-molten steel full furnace into the decarburization furnace without adding scrap steel; the ignition gun position of the decarburization furnace is 1600mm, and the ignition flow is 12000m3One minute later, use handThe oxygen supply amount of the oxygen lance is increased by a dynamic step method, and the oxygen blowing flow is gradually reduced in the later stage of smelting.
(4) The basicity R of a converter of the decarburization furnace is controlled to be 4.3, the tapping temperature is controlled to be 1620 ℃, carbon drawing is successful once, and the tapping carbon content is controlled to be 0.28 percent.
(5) 300kg of silicon carbide and 200kg of aluminum-containing top slag are added in sequence 1 minute before tapping; after strong stirring for 1 minute, the low-nitrogen carburant is added, and the carbon matching target is 0.89% after the furnace; then, the mixture is stirred strongly for 1 minute, and then alloy such as ferrosilicon, ferromanganese, ferrochrome, ferrovanadium, ferronickel and the like is added.
(6) The recovery rate of carbon after the converter steel is converted reaches 91%, the yield of Si alloy reaches 90%, the yield of Mn, Cr and Ni alloy reaches 99.92%, the alloy consumption is greatly reduced, and the smelting cost is reduced.
(7) After power is supplied for 10 minutes in the early stage of refining, 180kg of a calcium chloride slagging agent is added into top slag, and the interfacial tension of the steel slag is controlled to be 1.42N/m.
(8) The method comprises the steps of carrying out initial calibration on roll gap values of the press rolls under soft pressing before continuous casting production, setting the first roll gap value of the withdrawal and straightening unit to be 184.9mm, stabilizing the pressure difference between the upper roll and the lower roll at 0.89MPa during calibration, and setting the calibration error value of each roll gap value to be less than or equal to 0.43 mm.
(9) And if the actual tension value of the 5 th pair of rollers and the 6 th pair of rollers of each flow is lower than the standard value of 0.28Mpa, increasing the actual reduction in the displacement mode by 0.2 mm.
The inclusion analysis of the hard wire steel QS92Si high-carbon steel by an ASPEX scanning electron microscope shows that the components and the quantity of the inclusions are controlled as shown in figure 2, and the inclusion detection result in figure 2 shows that the size of the inclusions is less than 10 microns, so that the high cleanliness control level is achieved.
The carbon segregation index is shown in figure 3, the C segregation index reaches the level of less than or equal to 1.06, and the C element has better distribution uniformity from the detection result and can meet the quality requirements of ultrahigh-strength and ultrahigh-strength high-carbon hard wire steel.
Example 3
Selecting a furnace of steel for producing QS87MnSi steel, wherein the steel comprises the following components in percentage by weight: c: 0.87%, Si: 1.03%, Mn: 0.63%, Cr: 0.37%, P: 0.008%, S: 0.002%, Ni: 0.0001%, V: 0.13%, Cu: 0.04%, Al: 0.028%, N: 0.0026%, and the balance of Fe and inevitable impurities. The specific implementation process is as follows:
(1) the lance position is controlled to be 1200mm when the dephosphorization furnace blows, and the oxygen supply flow is 9600m3H; after blowing is finished, the lance is lifted and waits for 1 minute in a zero position state, and then the furnace is shaken to remove slag.
(2) Controlling the alkalinity R of a converter of the dephosphorizing furnace to be 2.10, controlling the tapping temperature of semisteel to be 1400 ℃, and adding 360kg of carburant in the tapping process of the dephosphorizing furnace; the oxygen consumption of the dephosphorizing furnace is controlled to be 10.86m3And t, reaching the advanced level of oxygen consumption control of duplex converters at home and abroad.
(3) Adding a semi-molten steel full furnace into the decarburization furnace without adding scrap steel; the ignition gun position of the decarburization furnace is 1560mm, and the ignition flow is 11000m3And h, increasing oxygen supply amount of the oxygen lance by adopting a manual step method after one minute, and gradually reducing oxygen blowing flow in the later smelting period.
(4) The basicity R of the converter of the decarburization furnace is controlled to be 3.96, the tapping temperature is controlled to be 1632 ℃, carbon drawing is successful once, and the tapping carbon content is controlled to be 0.29%.
(5) 300kg of silicon carbide and 200kg of aluminum-containing top slag are added in sequence 1 minute before tapping; after strong stirring for 1 minute, the low-nitrogen carburant is added, and the carbon adding target is 0.89% after the furnace; then, after strong stirring for 1 minute, adding ferrosilicon, ferromanganese, ferrochromium, ferrovanadium, ferronickel and other alloys;
(6) the recovery rate of carbon after the converter steel is converted reaches 93%, the yield of Si alloy reaches 92%, the yield of Mn, Cr and Ni alloy reaches 99.96%, the alloy consumption is greatly reduced, and the smelting cost is reduced.
(7) After power is supplied for 10 minutes in the early stage of refining, 200kg of a chlorine calcium slagging agent is added into top slag, and the interfacial tension of the steel slag is controlled to be 1.53N/m.
(8) The method comprises the steps of carrying out initial calibration on a roll gap value under soft pressing of each press roller before continuous casting production, setting the first roll gap value of a withdrawal and straightening machine to be 184.8mm, stabilizing the pressure difference between an upper roll and a lower roll at 0.92MPa during calibration, and setting the calibration error value of each roll gap value to be less than or equal to 0.36 mm.
(9) And if the actual tension value of the 3 rd pair roller and the 5 th pair roller of each flow is lower than the standard value of 0.19Mpa, increasing the actual reduction in the displacement mode by 0.2 mm.
The inclusion analysis of hard wire steel QS87MnSi high-carbon steel by an ASPEX scanning electron microscope shows that the components and the quantity of the inclusions are controlled as shown in figure 4, and the inclusion detection result in figure 4 shows that the size of the inclusions is less than 10 microns, so that the high cleanliness control level is achieved.
The carbon segregation index is shown in figure 5, the C segregation index reaches the level of less than or equal to 1.05, and the distribution uniformity of the C element is better from the detection result, so that the quality requirements of ultrahigh-strength and ultrahigh-strength high-carbon hard wire steel can be met.

Claims (2)

1. A smelting method based on alloyed ultra-high-strength and ultra-high-strength high-carbon hard wire steel sequentially comprises the following steps: the method is characterized in that the converter blowing adopts duplex converter blowing, the refining adopts a steel-slag interfacial tension adjusting method, the continuous casting adopts a pressure and displacement balance control method under light pressure, and the high-carbon hard wire steel comprises the following components in percentage by weight: c: 0.84-1.2%, Si: 0.15-1.5%, Mn: 0.35-0.80%, Cr: 0.10-0.80%, P: less than or equal to 0.015%, S: less than or equal to 0.010 percent, Ni: 0.0001-0.30%, V: 0.13-0.30%, Cu: less than or equal to 0.05 percent, Al: less than or equal to 0.10 percent, N: less than or equal to 0.005 percent, and the balance of Fe and inevitable impurities;
in the step of converter blowing, the lance position is controlled to 1100-1300mm during the dephosphorization furnace blowing, and the oxygen supply flow is 7000-12000m3After blowing is finished, lifting the lance, waiting for 1 minute in a zero position state, and then shaking the furnace to dump slag;
the basicity R of the converter of the dephosphorizing furnace is controlled to be 1.9-2.3, the tapping temperature of the semisteel is controlled to be 1300-1500 ℃, a carburant is added in the tapping process of the dephosphorizing furnace, the oxygen consumption of the dephosphorizing furnace is controlled to be 10-12m3 /t；
In the step of converting by the converter, the decarburization furnace is added with a full semi-molten steel furnace without adding scrap steel, the ignition lance position of the decarburization furnace is 1500-1600mm, and the ignition flow is 10000-12000m3After ignition for one minute, increasing oxygen supply of the oxygen lance by adopting a manual step method, and gradually reducing oxygen blowing flow in the later smelting period;
the basicity R of the converter of the decarburization furnace is controlled to be 3.0-5.0, the tapping temperature is controlled to be more than or equal to 1605 ℃, and in order to ensure the once successful carbon drawing, the tapping carbon content is controlled to be 0.20-0.30%;
in the refining step, after power is supplied for 5-15 minutes in the early stage of refining, a calcium chloride slagging agent is added into top slag, and the interfacial tension of the steel slag is controlled to be 1.25-1.70N/m;
in the continuous casting step, the roll gap value of each press roller is initially calibrated under light pressure before the continuous casting production, the first roll gap value of the withdrawal and straightening machine is set to be 184.5-185.5mm according to the outlet size of a copper pipe of a crystallizer and the cooling shrinkage of each high-carbon steel type, the pressure difference between an upper roll and a lower roll is stabilized to be 0.9-1.5MPa during calibration, and the calibration error value of each roll gap value is less than or equal to 0.5 mm.
2. The alloyed ultra-high strength and ultra-high strength high carbon hard wire steel-based smelting method according to claim 1, wherein: and establishing a soft reduction standard pressure value of each steel kind of each roller, if the actual tension value is lower than the standard value by 0.1-0.5MPa, increasing the actual reduction by 0.2mm in the displacement mode, otherwise, decreasing the actual reduction by 0.2 mm.
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