CN114318149A - Grade 102 steel cord, grade 102 cord steel wire rod and production method thereof - Google Patents
Grade 102 steel cord, grade 102 cord steel wire rod and production method thereof Download PDFInfo
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Abstract
The invention discloses a 102-grade steel cord, a 102-grade cord steel wire rod and a production method thereof. The production method comprises the following steps: in the steel smelting stage, molten steel with inclusion size less than or equal to 15 microns is smelted; in the casting blank stage, the central carbon segregation value of the continuous casting blank is less than or equal to 1.05, and the C in a segregation area is less than or equal to 1.09%; a cogging stage; and in the rolling stage, the chemical components of the rolled wire rod comprise the following components in percentage by mass: 1.00-1.04% of C, 0.2-0.3% of Si, 0.3-0.4% of Mn, 0.3-0.4% of Cr, less than or equal to 0.0020% of Al, less than or equal to 0.0006% of Ti, less than or equal to 0.003% of S, less than or equal to 0.008% of P, less than or equal to 0.03% of Cu, less than or equal to 0.02% of Ni, less than or equal to 0.0015% of O, less than or equal to 0.0030% of N, and the balance of Fe and other inevitable impurities; wherein, the content of Mn and Si satisfies: Mn/Si is 1.3-1.6; controlling temperature and cooling; and in the salt bath heat treatment stage, heating the temperature-controlled and cooled wire rod in a salt bath heating furnace, and then sending the wire rod into a salt bath for rapid cooling, wherein the temperature in the salt bath heating furnace is 960-980 ℃, the temperature of the molten salt is 520-540 ℃, and the wiring speed of the wire rod is 10-12 m/min. The invention solves the problems of limited strength and easy wire breakage during drawing of the cord steel caused by high carbon content.
Description
Technical Field
The invention belongs to the technical field of steel smelting, and relates to a production method of a 102-grade cord wire steel wire rod, a 102-grade cord wire steel wire rod prepared by the production method, and a 102-grade cord wire further processed by the 102-grade cord wire steel wire rod.
Background
With the rapid development of science and technology and the improvement of living standard of people, the production, sales and maintenance of automobiles in China leaps forward to the first place in the world, and along with the leap forward of higher requirements of people on the safety, comfort and low energy consumption of automobiles, tires with smaller rolling resistance, lighter weight and more wear resistance need to be developed.
As a main framework material of a meridian of tires of automobiles, trucks, airplanes and the like, the weight of the tires for the automobiles can be reduced by 10 percent for increasing the strength of a steel cord by one level. Therefore, the development of a higher-strength steel cord is a mainstream demand at present, and the strength of the steel cord is mainly improved by improving the carbon content in the industry at present, but with the continuous improvement of the carbon content, the manufacturing difficulty of the steel cord is also increased, and the problems of high drawing filament breakage rate, high strand twisting filament breakage rate, high die consumption, low yield and the like are mainly presented.
Disclosure of Invention
The invention aims to provide a production method of a 102-grade cord steel wire rod, the 102-grade cord steel wire rod prepared by the method and a 102-grade steel cord further processed by the 102-grade cord steel wire rod.
In order to achieve one of the above objects, an embodiment of the present invention provides a production method of a 102-grade cord steel wire rod, which comprises the following steps performed in sequence:
in the steel smelting stage, molten steel with inclusion size less than or equal to 15 microns is smelted;
in the casting blank stage, the molten steel is cast into a continuous casting blank, wherein the central carbon segregation value of the continuous casting blank is less than or equal to 1.05, and the C in a segregation area is less than or equal to 1.09%;
in the cogging stage, the continuous casting billet is heated by a heating furnace and then continuously rolled to form an intermediate billet, the intermediate billet is subjected to magnetic powder inspection, and the defective part is polished;
in the rolling stage, the polished intermediate blank is rolled into a wire rod through a high-speed wire, and the wire rod comprises the following chemical components in percentage by mass: 1.00-1.04% of C, 0.2-0.3% of Si, 0.3-0.4% of Mn, 0.3-0.4% of Cr, less than or equal to 0.0020% of Al, less than or equal to 0.0006% of Ti, less than or equal to 0.003% of S, less than or equal to 0.008% of P, less than or equal to 0.03% of Cu, less than or equal to 0.02% of Ni, less than or equal to 0.0015% of O, less than or equal to 0.0030% of N, and the balance of Fe and other inevitable impurities; wherein, the content of Mn and Si satisfies: Mn/Si is 1.3-1.6;
in the temperature control cooling stage, the wire rod is cooled at a controlled temperature on a stelmor cooling line;
and in the salt bath heat treatment stage, heating the temperature-controlled and cooled wire rod in a salt bath heating furnace, and then sending the wire rod into a salt bath for rapid cooling, wherein the temperature in the salt bath heating furnace is 960-980 ℃, the temperature of the molten salt is 520-540 ℃, and the wiring speed of the wire rod is 10-12 m/min.
In the wire rod, the chemical components and contents of C, Si, Mn and Cr have the following functions: c is taken as the most important alloy element, can obviously improve the strength of the steel and influence the tissue structure in the steel, but when the carbon content is too high, a proeutectoid reticular cementite tissue can be formed, and the tissue destroys the continuity of the eutectoid tissue, so that microcracks are formed in the wire drawing process, and even wire breakage is caused; si improves the strength of ferrite through solid solution strengthening, and is an important deoxidizer to reduce inclusions; mn is used as a main strengthening element in the steel and can change sulfide components; cr is a carbide-forming element, and is mainly present in steel in cementite sheets to form alloy cementite through substitution.
In addition, Al, Ti, Al, S, P, Cu, Ni, O, N are impurity elements which are not good for the processing performance of the wire rod, and the upper limit content of the impurity elements needs to be controlled, for example, Al is easy to combine with O in steel, aggregates to form high-melting point large-size inclusions, and deteriorates the wire drawing performance; the binding force of Ti and N is strong, large-size TiN brittle inclusion is easy to form, and the wire drawing performance is deteriorated; when the content of S, P is too high, component segregation is easy to generate at the final stage of molten steel solidification, and S can also form elongated MnS inclusions, which are unfavorable for wire rod drawing; o mainly exists in the form of inclusions in steel, and has great influence on the drawing performance; n causes age hardening during drawing, resulting in drawing breakage.
In addition, inclusions in the cord steel should be controlled to the lowest melting point region as much as possible to improve the deformability of the cord steel in the hot rolling and even wire drawing processes, so that the chemical components of the deoxidation product need to be controlled, and the ratio of the Mn content to the Si content is controlled to meet the requirement that the Mn/Si content is 1.3-1.6, thereby being beneficial to controlling the finally formed variable inclusions to the lowest melting point region.
Therefore, under the condition of controlling the content of C to be 1.00-1.04%, the contents of Si, Mn and Cr and the ratio of the contents of Mn and Si are optimized simultaneously, and the content of impurity elements is controlled, so that a 102-grade cord steel wire rod is prepared, the size control of inclusions in the steel smelting stage, the control of the central carbon segregation value of a continuous casting billet and the carbon content of a segregation region, temperature control cooling and salt bath heat treatment are combined, the sizes of the inclusions in the cord steel wire rod are reduced, the carbon segregation is reduced, the internal structure of the wire rod is uniform, internal microcracks caused by non-uniform deformation are reduced, the cooling rate before phase change is improved through salt bath heat treatment, the formation of network carbides in the wire rod can be inhibited, abnormal structures such as network carbides and martensite are eliminated, the sorbite rate of the wire rod is improved, the wire rod structure is more uniform, and under the conditions of improving the carbon content and preparing the high-strength cord steel wire rod, the drawing performance of the cord steel wire rod is improved.
In addition, the 102-grade cord wire steel wire rod prepared by the production method of the 102-grade cord wire steel wire rod has excellent mechanical properties, the tensile strength can reach more than 1300MPa, the fluctuation of the tensile strength is small, the reduction of area can reach more than 35%, the size of the largest inclusion is less than or equal to 15 microns, and the grade of the reticular carbide in the wire rod is within 1 grade.
As a further improvement of an embodiment of the present invention, the steel smelting stage comprises the following steps performed in sequence:
the molten iron is desulfurized in advance, adopts blast furnace molten iron to carry out the desulfurization at KR desulphurization unit, just blast furnace molten iron satisfies before the desulfurization: the temperature is more than or equal to 1360 ℃, the C is 4.0-4.5%, the S is less than or equal to 0.04%, the Ti is less than or equal to 0.04%, the Si is 0.20-0.60%, the P is less than or equal to 0.10%, the balance is Fe and other inevitable impurities, and the S in the molten iron after pre-desulfurization is less than or equal to 0.002%;
smelting in a converter, namely feeding the pretreated molten iron into the converter to be mixed with scrap steel to form molten steel, and carrying out desiliconization, dephosphorization, oxygen blowing and decarburization; the molten iron accounts for 83-88% of the molten steel, the scrap steel adopts high-quality scrap steel, and the high-quality scrap steel meets the following requirements: the thickness is more than or equal to 2cm, S is less than or equal to 0.02 percent, and P is less than or equal to 0.02 percent; the molten steel is deoxidized and alloyed by adding a recarburizing agent, ferrosilicon and manganese metal into a ladle, the tapping temperature of the molten steel is more than or equal to 1640 ℃, and the C in the molten steel is more than or equal to 0.05% during tapping.
A refining process, namely adjusting chemical components and regulating temperature of the molten steel smelted in the converter in an LF (ladle furnace), adding 8-12 kg/t of refining covering agent to the surface of the molten steel, electrifying to melt the refining covering agent, and controlling the intensity of argon blown from the bottom of a steel ladle to be less than or equal to 0.005Nm3V (t.min) SiO in the inclusions of molten steel2The content of the component is more than or equal to 40 percent, the content of the CaO component is less than or equal to 30 percent, and Al2O3The content of the components is less than or equal to 10 percent,and controlling inclusions in the molten steel by soft stirring, wherein the soft stirring time is more than or equal to 30min, and the flow of argon blown from the bottom of the steel ladle during soft stirring is 0.5-0.7L/min.t.
The desulphurization effect can be ensured by optimizing equipment and controlling the components and the content of molten iron so as to effectively control the content of residual elements and the steelmaking process, and the low-Ti molten iron is adopted for smelting, so that the phenomenon that slag is returned due to slag discharge can be effectively avoided, and further the phenomenon that fragile inclusions such as titanium oxide and titanium nitride are separated out in the continuous casting process is avoided; the content of P and the subsequent steelmaking process are further controlled by controlling the tapping temperature, so that the inclusions are controlled; the carbon content of the steel tapping is controlled to be more than or equal to 0.05 percent, so that the molten steel can be prevented from being oxidized, and the content of primary inclusion and the production cost are reduced; through deoxidation alloying treatment, on one hand, the O content in the molten steel can be reduced, the oxide content formed in the deoxidation process is greatly reduced, and the increase of the N content in the molten steel caused in the deoxidation alloying process is reduced, so that the generation of fragile inclusions such as titanium oxide, aluminum oxide, titanium nitride and the like is effectively avoided, and the cleanliness of the wire rod and the steel cord is improved; on the other hand, the aging hardening caused in the drawing process due to the addition of the carburant in the deoxidation alloying process can be controlled, and the drawing wire breakage rate is reduced; the content of each component in the inclusion can be further effectively controlled through the refining process, so that the cleanliness of the wire rod and the steel cord is improved, for example, the inclusion can be well removed through soft stirring, and the inclusion can sufficiently float upwards through controlling the flow of bottom blowing argon, and the inclusion is prevented from being involved in refining slag.
In a further improvement of an embodiment of the present invention, in the refining step, slag is formed by using slag, and the slag basicity of the slag is 2.5 to 3.0. Thus being beneficial to adsorbing a large amount of acid inclusions generated in the smelting process of the converter and reducing SiO in molten steel2The content of the similar inclusion is reduced, and the severe fluctuation of the inclusion components in the molten steel is reducedAnd uncontrollable and reduced erosion of the refractory walls of the ladle.
As a further improvement of one embodiment of the invention, in the casting blank stage, the superheat degree of the tundish is controlled to be 15-20 ℃, the casting pulling speed is 0.64-0.66 m/min, the total reduction is 23-28 mm, and the reduction of a single roller is less than or equal to 5 mm. By adopting low superheat degree and constant drawing speed in the casting blank stage, the liquid level fluctuation of the tundish in the casting process can be reduced, slag entrapment is avoided, and the macrosegregation of the continuous casting blank is reduced; by controlling the total reduction and the reduction of a light single roller, the cavity negative pressure generated by solidification shrinkage of the central area of the continuous casting billet can be prevented, molten steel with solute elements enriched in crystal is prevented from flowing to the central area, the macrosegregation of the billet is greatly reduced, cracks are prevented from being generated in the billet, and the structure uniformity of the wire rod for the 102-level steel cord is improved.
According to a further improvement of one embodiment of the invention, in the temperature-controlled cooling stage, the spinning temperature is 910-930 ℃, the air volume of No. 1-4 fans is 100%, the rest fans are closed, the average speed of a roller way is 72-75 m/min, the average cooling speed before pearlite phase transformation is 13-17 ℃/1, and the average cooling speed during pearlite phase transformation is 5-10 ℃/1. The control of the temperature and the cooling speed of the wire rod is realized by controlling the speed of a fan and a roller way of a stelmor cooling line, the function of the air cooling line is fully exerted, the transformation from super-cooled austenite to pearlite is promoted, the phase transformation time of the pearlite is shortened, the netlike cementite is reduced, the formation of low-temperature bainite and martensite quenching structures is prevented, and the structure uniformity of the wire rod for the 102-grade steel cord is improved.
In order to achieve one of the above objects, an embodiment of the present invention further provides a grade 102 cord steel wire rod, which is prepared by the above-mentioned production method of the grade 102 cord steel wire rod.
As a further improvement of one embodiment of the invention, the diameter of the 102-grade cord steel wire rod is 5.0-6.5 mm, the tensile strength is not less than 1300MPa, the reduction of area is not less than 35%, and the drawing filament breakage rate is not more than 2 times/ton.
As a further improvement of one embodiment of the invention, the 102-grade cord steel wire rod has the largest inclusion size of less than or equal to 15 microns, and the net-shaped carbide in the wire rod is less than or equal to 1 grade.
In order to achieve one of the above objects, an embodiment of the present invention further provides a 102-grade steel cord, wherein the 102-grade cord steel is prepared by taking the 102-grade cord steel wire rod as a base material.
As a further improvement of an embodiment of the present invention, the 102-grade steel cord is formed by twisting monofilaments with a diameter of 0.20mm, the monofilaments are prepared by drawing the 102-grade cord steel wire rod as a base material, the tensile strength of the monofilaments is not less than 4000MPa, and the monofilaments can be used for producing an ultra-high strength steel cord, namely a UT-grade steel cord, and can further realize the light weight of an automobile tire.
Compared with the prior art, the invention has the beneficial effects that: not only the rolling of 102-grade steel cord is realized, but also the sizes of the inclusions in the cord steel wire rod are reduced, the carbon segregation is reduced, the internal structure of the wire rod is homogenized, the internal microcrack caused by non-uniform deformation is reduced, the cooling speed before phase change is improved by the salt bath heat treatment, the formation of the net-shaped carbide in the wire rod can be inhibited, the abnormal structures such as net-shaped carbide and martensite are eliminated, the sorbite rate of the wire rod is improved, the wire rod structure is more uniform, and a series of defects and broken wires caused by the generation of abnormal structures such as carbon segregation, net-shaped cementite and martensite are avoided under the conditions of improving the carbon content and preparing the high-strength cord steel wire rod The drawing performance of the prepared 102-grade cord steel wire rod is ensured, the tensile strength can reach more than 1300MPa, the reduction of area can reach more than 35%, the drawing broken wire rate is 1.4-1.8 times per ton, the problems of strength limitation and drawing easy broken wire caused by high carbon content, macrosegregation and the formation of reticular cementite of the cord steel wire rod are solved, and the light weight of the automobile tire can be further realized.
Detailed Description
A large number of researches show that in an iron-carbon binary system, the carbon content of 0.76 percent is a thermodynamic eutectoid point, and a 100 percent eutectoid pearlite structure is obtained theoretically after slow cooling, so that the steel with the carbon content of more than 0.76 percent is called hypereutectoid steel, and a eutectoid pearlite and pro-eutectoid cementite mixed structure is obtained after slow cooling. When more eutectoid cementite exists, the eutectoid cementite is connected to form a net on austenite grain boundaries to form a net cementite, and the net cementite is a fatal defect for high-carbon steel, can damage the continuity of a steel matrix and is easy to cause wire breakage during drawing.
The carbon content in the 102-grade cord steel wire rod is more than or equal to 1%, macrosegregation is easily generated in a billet, abnormal structures such as net-shaped cementite and martensite are formed, and therefore, macrosegregation and the formation of the net-shaped cementite need to be improved in a targeted manner, so that a series of defects of the cord steel wire rod, such as core brittle fracture during drawing of a rolled piece, caused by macrosegregation and the precipitation of the net-shaped cementite are avoided.
One embodiment of the present invention provides a method for producing a 102-grade cord steel wire rod, which is obtained according to a large number of experimental studies as described above, and the steps of each stage of the production method are further described below with reference to specific examples.
A method for producing a grade 102 cord steel wire rod, comprising the following stages carried out in sequence:
in the stage of smelting steel, molten steel with inclusion size less than or equal to 15 microns is smelted.
Specifically, the steel smelting stage comprises the following processes which are sequentially carried out:
(1) the molten iron is desulfurized in advance, adopts blast furnace molten iron to carry out the desulfurization at KR desulphurization unit, just blast furnace molten iron satisfies before the desulfurization: the temperature is more than or equal to 1360 ℃, the C is 4.0-4.5%, the S is less than or equal to 0.04%, the Ti is less than or equal to 0.04%, the Si is 0.20-0.60%, the P is less than or equal to 0.10%, the balance is Fe and other inevitable impurities, and the S in the molten iron after pre-desulfurization is less than or equal to 0.002%.
Preferably, the blast furnace slag in the ladle is removed before desulfurization, and the slag removing rate is 80-90%.
(2) Smelting in a converter, namely feeding the pretreated molten iron into the converter to be mixed with scrap steel to form molten steel, and carrying out desiliconization, dephosphorization, oxygen blowing and decarburization; the molten iron accounts for 83-88% of the molten steel, the scrap steel adopts high-quality scrap steel, and the high-quality scrap steel meets the following requirements: the thickness is more than or equal to 2cm, S is less than or equal to 0.02 percent, and P is less than or equal to 0.02 percent; the molten steel is deoxidized and alloyed by adding a recarburizing agent, ferrosilicon and manganese metal into a ladle, the tapping temperature of the molten steel is more than or equal to 1640 ℃, and the C in the molten steel is more than or equal to 0.05% during tapping.
Specifically, when tapping is started, ferrosilicon, manganese metal and 30% of carburant are added into a ladle for deoxidation alloying, the rest of carburant is added when 85% of tapping is finished, and lime and synthetic slag are added for slagging after the tapping is finished. The carburant is added in batches, so that the boiling degree of the molten steel can be reduced, the production safety is improved, the carburant is dissolved in the molten steel, the time required by deoxidation alloying is shortened, and the amount of air entering the molten steel is reduced.
(3) A refining process, namely adjusting chemical components and regulating temperature of the molten steel smelted by the converter in an LF (ladle furnace), adding 8-12 kg/t of refining covering agent to the surface of the molten steel, electrifying to melt the refining covering agent, and controlling the intensity of argon blown from the bottom of a steel ladle to be less than or equal to 0.005Nm3V (t.min) SiO in the inclusions of molten steel2The content of the component is more than or equal to 40 percent, the content of the CaO component is less than or equal to 30 percent, and Al2O3The content of the components is less than or equal to 10 percent, the inclusion in the molten steel is regulated and controlled through soft stirring, the soft stirring time is more than or equal to 30min, and the flow of argon blown from the bottom of the steel ladle during soft stirring is 0.5-0.7L/min.t.
Preferably, in the refining process, slag is used for slagging, and the slag alkalinity of the slag is 2.5-3.0.
And (II) casting a blank, namely casting the molten steel into a continuous casting blank, wherein the central carbon segregation value of the continuous casting blank is less than or equal to 1.05, and the C in a segregation area is less than or equal to 1.09%.
Preferably, in the casting blank stage, an electromagnetic induction heating device is adopted to regulate and control the temperature of molten steel in the tundish, the superheat degree of the tundish is controlled to be 15-20 ℃, the casting pulling speed is 0.64-0.66 m/min, the total reduction in the continuous casting blank solidification process is controlled to be 23-28 mm, and the reduction of a single roller is less than or equal to 5 mm.
And (III) in the cogging stage, heating the continuous casting billet by a heating furnace, continuously rolling the continuous casting billet to form an intermediate billet, carrying out magnetic powder inspection on the intermediate billet, and grinding the defective part.
Specifically, the grinding process is to perform surface treatment on the intermediate blank after cogging to remove defects on the surface of the intermediate blank, so that the surface of the intermediate blank is smooth and free of defects such as oxide skin and surface cracks, and adverse effects of the original defects of the intermediate blank on a subsequent production process are avoided.
And (IV) rolling the polished intermediate blank into a wire rod through a high-speed wire, wherein the wire rod comprises the following chemical components in percentage by mass: 1.00-1.04% of C, 0.2-0.3% of Si, 0.3-0.4% of Mn, 0.3-0.4% of Cr, less than or equal to 0.0020% of Al, less than or equal to 0.0006% of Ti, less than or equal to 0.003% of S, less than or equal to 0.008% of P, less than or equal to 0.03% of Cu, less than or equal to 0.02% of Ni, less than or equal to 0.0015% of O, less than or equal to 0.0030% of N, and the balance of Fe and other inevitable impurities; wherein, the content of Mn and Si satisfies: Mn/Si is 1.3 to 1.6.
And (V) in the temperature-controlled cooling stage, performing temperature-controlled cooling on the wire rod on a stelmor cooling line.
Preferably, in the temperature-controlled cooling stage, the spinning temperature is 910-930 ℃, the air volume of the No. 1-4 fan is 100%, the rest fans are closed, the average speed of the roller way is 72-75 m/min, the average cooling speed before pearlite phase transformation is 13-17 ℃/1, and the average cooling speed during pearlite phase transformation is 5-10 ℃/1.
And (VI) in the salt bath heat treatment stage, heating the wire rod subjected to temperature control cooling in a salt bath heating furnace, and then sending the wire rod into a salt bath for rapid cooling, wherein the temperature in the salt bath heating furnace is 960-980 ℃, the temperature of the molten salt is 520-540 ℃, and the wiring speed of the wire rod is 10-12 m/min.
In addition, the invention also provides a 102-grade cord steel wire rod, the 102-grade cord steel wire rod is prepared by the production method of the 102-grade cord steel wire rod, the diameter of the 102-grade cord steel wire rod is 5.0-6.5 mm, the tensile strength is larger than or equal to 1300MPa, the fluctuation of the tensile strength is small, the reduction of area is larger than or equal to 35%, the drawing filament breakage rate is smaller than or equal to 2 times per ton, the size of the largest inclusion is smaller than or equal to 15 mu m, and the mesh carbide in the wire rod is smaller than or equal to 1 grade.
In addition, the invention also provides a 102-grade steel cord, the 102-grade steel cord is prepared by taking the 102-grade cord steel wire rod as a base material, the 102-grade steel cord is formed by twisting monofilaments with the diameter of 0.20mm, the monofilaments are prepared by taking the 102-grade cord steel wire rod as a base material through drawing, the mechanical property is excellent through detection, the tensile strength of the monofilaments can reach more than 4000MPa, and the light weight of automobile tires can be further realized.
As described above, the present invention has been made in accordance with a number of experimental studies, and in order to make the objects, technical solutions, and advantages of an embodiment of the present invention more apparent, the embodiment will be specifically described below with reference to examples 1 to 5 according to an embodiment of the present invention and comparative examples 1 to 3 not according to an embodiment of the present invention. It is clear that the embodiments 1 to 5 described are some, but not all embodiments of the present invention.
Specifically, examples 1 to 5 and comparative examples 1 to 3 each provide a wire rod, each of which has chemical components in mass percent as shown in table 1.
[ Table 1]
As can be seen from table 1, examples 1 to 5 all conform to the design scheme of the chemical components of the 102-grade cord steel wire rod in one embodiment of the present invention, that is, the chemical components include, by mass: 1.00-1.04% of C, 0.2-0.3% of Si, 0.3-0.4% of Mn, 0.3-0.4% of Cr, less than or equal to 0.0020% of Al, less than or equal to 0.0006% of Ti, less than or equal to 0.003% of S, less than or equal to 0.008% of P, less than or equal to 0.03% of Cu, less than or equal to 0.02% of Ni, less than or equal to 0.0015% of O, less than or equal to 0.0030% of N, and the balance of Fe and other inevitable impurities; wherein, the content of Mn and Si satisfies: Mn/Si is 1.3 to 1.6. And the comparative examples 1 to 3 do not conform to the chemical composition design scheme. The production methods of the respective examples are described in detail below.
Example 1
The steel smelting stage comprises the following steps of:
(1) pre-desulphurisation of molten iron
The blast furnace slag in the ladle is removed before desulfurization, the slag removal rate is 81%, the blast furnace molten iron is adopted to carry out desulfurization in a KR desulfurization device, and the blast furnace molten iron meets the following requirements before desulfurization: the temperature is 1363 ℃, C4.0-4.5%, S is less than or equal to 0.04%, Ti is less than or equal to 0.04%, Si is 0.20-0.60%, P is less than or equal to 0.10%, and the balance is Fe and other inevitable impurities, and the S content in the molten iron after pre-desulfurization is 0.0013%.
(2) Smelting in a converter
Feeding the pretreated molten iron into a converter to be mixed with scrap steel to form molten steel, and carrying out desiliconization, dephosphorization, oxygen blowing and decarburization; the molten iron accounts for 86% of the molten steel, the scrap steel adopts high-quality scrap steel, and the high-quality scrap steel meets the following requirements: the thickness is more than or equal to 2cm, S is less than or equal to 0.02 percent, and P is less than or equal to 0.02 percent; when tapping begins, firstly adding ferrosilicon, metal manganese and 30% of carburant into a ladle for deoxidation alloying, adding the rest carburant when the tapping reaches 85%, and adding lime and synthetic slag for slagging after the tapping is finished; the tapping temperature of the molten steel is 1645 ℃, and the content of C in the molten steel is 0.06 percent during tapping.
(3) Refining procedure
Carrying out chemical component adjustment and temperature regulation on the molten steel smelted by the converter in an LF (ladle furnace) refining furnace, adding 9kg/t of refining covering agent to the surface of the molten steel, electrifying and melting the refining covering agent, and controlling the intensity of argon blown from the bottom of a steel ladle to be less than or equal to 0.005Nm3V (t.min) SiO in the inclusions of molten steel245% of CaO component, 28% of Al2O3The content of the components is 9 percent; slag is adopted for slagging, the slag alkalinity of the slag is 2.7, inclusions in molten steel are regulated and controlled through soft stirring, the soft stirring time is 33min, and the flow of argon blown from the bottom of a steel ladle during soft stirring is 0.5L/min t.
The size of the inclusions in the molten steel finally smelted is less than or equal to 15 mu m.
(II) casting stage
And casting the molten steel into a continuous casting billet, and regulating and controlling the temperature of the molten steel in the tundish by adopting an electromagnetic induction heating device, wherein the superheat degree of the tundish is controlled to be 16 ℃, the casting drawing speed is 0.64m/min, the total reduction in the solidification process of the continuous casting billet is controlled to be 24mm, and the reduction of a No. 5-11 withdrawal and straightening machine is respectively 2mm, 4mm, 5mm, 3mm and 3 mm.
The center carbon segregation value of the continuous casting slab was measured to be 1.04, and the C content of the segregation region was 1.07%.
(III) cogging stage
And heating the continuous casting billet by a heating furnace, continuously rolling the continuous casting billet to form an intermediate billet, carrying out magnetic powder inspection on the intermediate billet, and grinding the defect part, namely carrying out surface treatment on the intermediate billet after cogging to remove the defect on the surface of the intermediate billet.
(IV) Rolling stage
And rolling the polished intermediate blank into a wire rod with the diameter of 5.0mm through a high wire.
(V) temperature-controlled cooling stage
And carrying out temperature control cooling on the wire rod on a stelmor cooling line, wherein the spinning temperature is 925 ℃, the air volume of a No. 1-4 fan is 100%, the rest fans are closed, the average speed of a roller way is 72m/min, the average cooling speed before pearlite phase transformation is 15 ℃/1, and the average cooling speed during pearlite phase transformation is 7 ℃/1.
(VI) salt bath Heat treatment stage
And heating the wire rod cooled by controlling the temperature in a salt bath heating furnace, then sending the wire rod into a salt bath for rapid cooling, wherein the temperature in the salt bath heating furnace is 965 ℃, the temperature of molten salt is 535 ℃, the wiring speed of the wire rod is 12m/min, and collecting coils to finally obtain a finished wire rod product.
The obtained wire rod product was tested for inclusions, texture and mechanical properties, and the results are shown in table 2, including the size of the largest inclusions, the mesh cementite (i.e., the mesh carbon in table 2), the tensile strength and the reduction of area of the wire rod.
(VII) drawing stage
The finished wire rod is drawn into a monofilament with a diameter of 0.2mm, the tensile strength and the breakage rate of the monofilament are detected, and the measured results are shown in table 2.
Example 2
The steel smelting stage comprises the following steps of:
(1) pre-desulphurisation of molten iron
The blast furnace slag in the ladle is removed before desulfurization, the slag removal rate is 84%, the blast furnace molten iron is adopted to carry out desulfurization in a KR desulfurization device, and the blast furnace molten iron meets the following requirements before desulfurization: the temperature is 1370 ℃, C4.0-4.5%, S is less than or equal to 0.04%, Ti is less than or equal to 0.04%, Si is 0.20-0.60%, P is less than or equal to 0.10%, the balance is Fe and other inevitable impurities, and the S content in the pre-desulfurized molten iron is 0.0015%.
(2) Smelting in a converter
Feeding the pretreated molten iron into a converter to be mixed with scrap steel to form molten steel, and carrying out desiliconization, dephosphorization, oxygen blowing and decarburization; the molten iron accounts for 86% of the molten steel, the scrap steel adopts high-quality scrap steel, and the high-quality scrap steel meets the following requirements: the thickness is more than or equal to 2cm, S is less than or equal to 0.02 percent, and P is less than or equal to 0.02 percent; when tapping begins, firstly adding ferrosilicon, metal manganese and 30% of carburant into a ladle for deoxidation alloying, adding the rest carburant when the tapping reaches 85%, and adding lime and synthetic slag for slagging after the tapping is finished; the tapping temperature of the molten steel is 1644 ℃, and the content of C in the molten steel is 0.05 percent during tapping.
(3) Refining procedure
Carrying out chemical component adjustment and temperature regulation on the molten steel smelted by the converter in an LF (ladle furnace) refining furnace, adding 11kg/t of refining covering agent to the surface of the molten steel, electrifying and melting the refining covering agent, and controlling the intensity of argon blown from the bottom of a steel ladle to be less than or equal to 0.005Nm3V (t.min) SiO in the inclusions of molten steel248% of component, 27% of CaO component, Al2O3The content of the components is 8 percent; slag is adopted for slagging, the slag alkalinity of the slag is 2.8, inclusions in molten steel are regulated and controlled through soft stirring, the soft stirring time is 34min, and the flow of argon blown from the bottom of a steel ladle during soft stirring is 0.6L/min t.
The size of the inclusions in the molten steel finally smelted is less than or equal to 15 mu m.
(II) casting stage
And casting the molten steel into a continuous casting billet, and regulating and controlling the temperature of the molten steel in the tundish by adopting an electromagnetic induction heating device, wherein the superheat degree of the tundish is controlled to be 19 ℃, the casting drawing speed is 0.66m/min, the total reduction in the solidification process of the continuous casting billet is controlled to be 25mm, and the reduction of a No. 5-11 withdrawal and straightening machine is respectively 2mm, 4mm, 5mm, 4mm and 3 mm.
The central carbon segregation value of the continuous casting slab is 1.03, and the C content of the segregation region is 1.05%.
(III) cogging stage
And heating the continuous casting billet by a heating furnace, continuously rolling the continuous casting billet to form an intermediate billet, carrying out magnetic powder inspection on the intermediate billet, and grinding the defect part, namely carrying out surface treatment on the intermediate billet after cogging to remove the defect on the surface of the intermediate billet.
(IV) Rolling stage
And rolling the polished intermediate blank into a wire rod with the diameter of 5.0mm through a high wire.
(V) temperature-controlled cooling stage
And carrying out temperature control cooling on the wire rod on a stelmor cooling line, wherein the spinning temperature is 911 ℃, the air volume of a No. 1-4 fan is 100%, the rest fans are closed, the average speed of a roller way is 73m/min, the average cooling speed before pearlite phase transformation is 16 ℃/1, and the average cooling speed during pearlite phase transformation is 9 ℃/1.
(VI) salt bath Heat treatment stage
And heating the wire rod cooled by controlling the temperature in a salt bath heating furnace, then sending the wire rod into a salt bath for rapid cooling, wherein the temperature in the salt bath heating furnace is 965 ℃, the temperature of molten salt is 530 ℃, the wiring speed of the wire rod is 12m/min, and collecting coils to finally obtain a finished wire rod product.
The obtained wire rod product was tested for inclusions, texture and mechanical properties, and the results are shown in table 2, including the size of the largest inclusions, the mesh cementite (i.e., the mesh carbon in table 2), the tensile strength and the reduction of area of the wire rod.
(VII) drawing stage
The finished wire rod is drawn into a monofilament with a diameter of 0.2mm, the tensile strength and the breakage rate of the monofilament are detected, and the measured results are shown in table 2.
Example 3
The steel smelting stage comprises the following steps of:
(1) pre-desulphurisation of molten iron
The blast furnace slag in the ladle is taken off before the desulfurization, the slag-off rate is 89%, the blast furnace molten iron is adopted to carry out the desulfurization in the KR desulfurization device, and the blast furnace molten iron meets the following requirements before the desulfurization: the temperature is 1360 ℃, 4.0-4.5% of C, less than or equal to 0.04% of S, less than or equal to 0.04% of Ti, 0.20-0.60% of Si, less than or equal to 0.10% of P, and the balance of Fe and other inevitable impurities, wherein the S content in the molten iron after pre-desulfurization is 0.002%.
(2) Smelting in a converter
Feeding the pretreated molten iron into a converter to be mixed with scrap steel to form molten steel, and carrying out desiliconization, dephosphorization, oxygen blowing and decarburization; wherein the molten iron accounts for 84% in the molten steel, the scrap steel adopts high-quality scrap steel, and the high-quality scrap steel meets the following requirements: the thickness is more than or equal to 2cm, S is less than or equal to 0.02 percent, and P is less than or equal to 0.02 percent; when tapping begins, firstly adding ferrosilicon, metal manganese and 30% of carburant into a ladle for deoxidation alloying, adding the rest carburant when the tapping reaches 85%, and adding lime and synthetic slag for slagging after the tapping is finished; the tapping temperature of the molten steel is 1645 ℃, and the content of C in the molten steel is 0.06 percent during tapping.
(3) Refining procedure
Carrying out chemical component adjustment and temperature regulation on molten steel smelted by a converter in an LF (ladle furnace) refining furnace, adding 10kg/t of refining covering agent to the surface of the molten steel, electrifying to melt the refining covering agent, and controlling the argon blowing intensity at the bottom of a steel ladle to be less than or equal to 0.005Nm3V (t.min) SiO in the inclusions of molten steel247% of CaO component, 23% of Al2O3The content of the components is 9 percent; slag is adopted for slagging, the slag alkalinity of the slag is 2.6, inclusions in molten steel are regulated and controlled through soft stirring, the soft stirring time is 33min, and the flow of argon blown from the bottom of a steel ladle during soft stirring is 0.7L/min t.
The size of the inclusions in the molten steel finally smelted is less than or equal to 15 mu m.
(II) casting stage
And casting the molten steel into a continuous casting billet, adopting an electromagnetic induction heating device to regulate and control the temperature of the molten steel of the tundish, controlling the superheat degree of the tundish to be 15 ℃, the casting drawing speed to be 0.64m/min, controlling the total reduction of the continuous casting billet in the solidification process to be 26mm, and controlling the reduction of 5-11 # withdrawal and straightening machines to be 2mm, 5mm, 4mm and 3mm respectively.
The central carbon segregation value of the continuous casting slab is 1.02, and the C content of the segregation region is 1.06%.
(III) cogging stage
And heating the continuous casting billet by a heating furnace, continuously rolling the continuous casting billet to form an intermediate billet, carrying out magnetic powder inspection on the intermediate billet, and grinding the defect part, namely carrying out surface treatment on the intermediate billet after cogging to remove the defect on the surface of the intermediate billet.
(IV) Rolling stage
And rolling the polished intermediate blank into a wire rod with the diameter of 5.5mm through a high wire.
(V) temperature-controlled cooling stage
And carrying out temperature control cooling on the wire rod on a stelmor cooling line, wherein the spinning temperature is 920 ℃, the air volume of a No. 1-4 fan is 100%, the rest fans are closed, the average speed of a roller way is 72m/min, the average cooling speed before pearlite phase transformation is 16 ℃/1, and the average cooling speed during pearlite phase transformation is 7 ℃/1.
(VI) salt bath Heat treatment stage
And heating the wire rod cooled by controlling the temperature in a salt bath heating furnace, then sending the wire rod into a salt bath for rapid cooling, wherein the temperature in the salt bath heating furnace is 970 ℃, the temperature of molten salt is 527 ℃, the wiring speed of the wire rod is 11.5m/min, and collecting coils to finally obtain a finished wire rod product.
The obtained wire rod product was tested for inclusions, texture and mechanical properties, and the results are shown in table 2, including the size of the largest inclusions, the mesh cementite (i.e., the mesh carbon in table 2), the tensile strength and the reduction of area of the wire rod.
(VII) drawing stage
The finished wire rod is drawn into a monofilament with a diameter of 0.2mm, the tensile strength and the breakage rate of the monofilament are detected, and the measured results are shown in table 2.
Example 4
The steel smelting stage comprises the following steps of:
(1) pre-desulphurisation of molten iron
The blast furnace slag in the ladle is removed before desulfurization, the slag removal rate is 85%, the blast furnace molten iron is adopted to carry out desulfurization in a KR desulfurization device, and the blast furnace molten iron meets the following requirements before desulfurization: the temperature is 1368 ℃, C4.0-4.5%, S is less than or equal to 0.04%, Ti is less than or equal to 0.04%, Si is 0.20-0.60%, P is less than or equal to 0.10%, and the balance is Fe and other inevitable impurities, and the S content in the molten iron after pre-desulfurization is 0.0013%.
(2) Smelting in a converter
Feeding the pretreated molten iron into a converter to be mixed with scrap steel to form molten steel, and carrying out desiliconization, dephosphorization, oxygen blowing and decarburization; the molten iron accounts for 87% of the molten steel, the scrap steel adopts high-quality scrap steel, and the high-quality scrap steel meets the following requirements: the thickness is more than or equal to 2cm, S is less than or equal to 0.02 percent, and P is less than or equal to 0.02 percent; when tapping begins, firstly adding ferrosilicon, metal manganese and 30% of carburant into a ladle for deoxidation alloying, adding the rest carburant when the tapping reaches 85%, and adding lime and synthetic slag for slagging after the tapping is finished; the tapping temperature of the molten steel is 1647 ℃, and the content of C in the molten steel is 0.07 percent during tapping.
(3) Refining procedure
Carrying out chemical component adjustment and temperature regulation on the molten steel smelted by the converter in an LF (ladle furnace) refining furnace, adding 11kg/t of refining covering agent to the surface of the molten steel, electrifying and melting the refining covering agent, and controlling the intensity of argon blown from the bottom of a steel ladle to be less than or equal to 0.005Nm3V (t.min) SiO in the inclusions of molten steel244% of CaO component, 29% of Al2O3The content of the components is 9 percent; slag is adopted for slagging, the slag alkalinity of the slag is 2.6, inclusions in molten steel are regulated and controlled through soft stirring, the soft stirring time is 34min, and the flow of argon blown from the bottom of a steel ladle during soft stirring is 0.6L/min t.
The size of the inclusions in the molten steel finally smelted is less than or equal to 15 mu m.
(II) casting stage
And casting the molten steel into a continuous casting billet, adopting an electromagnetic induction heating device to regulate and control the temperature of the molten steel of the tundish, controlling the superheat degree of the tundish to be 18 ℃, the casting drawing speed to be 0.65m/min, controlling the total reduction of the continuous casting billet in the solidification process to be 25mm, and controlling the reduction of 5-11 # withdrawal and straightening machines to be 2mm, 4mm, 5mm, 4mm and 3mm respectively.
The center carbon segregation value of the continuous casting slab is 1.04, and the C content of the segregation region is 1.05%.
(III) cogging stage
And heating the continuous casting billet by a heating furnace, continuously rolling the continuous casting billet to form an intermediate billet, carrying out magnetic powder inspection on the intermediate billet, and grinding the defect part, namely carrying out surface treatment on the intermediate billet after cogging to remove the defect on the surface of the intermediate billet.
(IV) Rolling stage
And rolling the polished intermediate blank into a wire rod with the diameter of 6.5mm through a high wire.
(V) temperature-controlled cooling stage
And carrying out temperature-controlled cooling on the wire rod on a stelmor cooling line, wherein the spinning temperature is 913 ℃, the air volume of a No. 1-4 fan is 100%, the rest fans are closed, the average speed of a roller way is 74m/min, the average cooling speed before pearlite phase transformation is 16 ℃/1, and the average cooling speed during pearlite phase transformation is 6 ℃/1.
(VI) salt bath Heat treatment stage
And heating the wire rod cooled by controlling the temperature in a salt bath heating furnace, then sending the wire rod into a salt bath for rapid cooling, wherein the temperature in the salt bath heating furnace is 978 ℃, the temperature of molten salt is 535 ℃, the wiring speed of the wire rod is 11.4m/min, and collecting coils to finally obtain a finished wire rod product.
The obtained wire rod product was tested for inclusions, texture and mechanical properties, and the results are shown in table 2, including the size of the largest inclusions, the mesh cementite (i.e., the mesh carbon in table 2), the tensile strength and the reduction of area of the wire rod.
(VII) drawing stage
The finished wire rod is drawn into a monofilament with a diameter of 0.2mm, the tensile strength and the breakage rate of the monofilament are detected, and the measured results are shown in table 2.
Example 5
The steel smelting stage comprises the following steps of:
(1) pre-desulphurisation of molten iron
The blast furnace slag in the ladle is removed before desulfurization, the slag removal rate is 88%, the blast furnace molten iron is adopted to carry out desulfurization in a KR desulfurization device, and the blast furnace molten iron meets the following requirements before desulfurization: the temperature is 1360 ℃, 4.0-4.5% of C, less than or equal to 0.04% of S, less than or equal to 0.04% of Ti, 0.20-0.60% of Si, less than or equal to 0.10% of P, and the balance of Fe and other inevitable impurities, wherein the S content in the pre-desulfurized molten iron is 0.0012%.
(2) Smelting in a converter
Feeding the pretreated molten iron into a converter to be mixed with scrap steel to form molten steel, and carrying out desiliconization, dephosphorization, oxygen blowing and decarburization; wherein the molten iron accounts for 84% in the molten steel, the scrap steel adopts high-quality scrap steel, and the high-quality scrap steel meets the following requirements: the thickness is more than or equal to 2cm, S is less than or equal to 0.02 percent, and P is less than or equal to 0.02 percent; when tapping begins, firstly adding ferrosilicon, metal manganese and 30% of carburant into a ladle for deoxidation alloying, adding the rest carburant when the tapping reaches 85%, and adding lime and synthetic slag for slagging after the tapping is finished; the tapping temperature of the molten steel is 1645 ℃, and the content of C in the molten steel is 0.06 percent during tapping.
(3) Refining procedure
Carrying out chemical component adjustment and temperature regulation on the molten steel smelted by the converter in an LF (ladle furnace) refining furnace, adding 8kg/t of refining covering agent to the surface of the molten steel, electrifying and melting the refining covering agent, and controlling the intensity of argon blown from the bottom of a steel ladle to be less than or equal to 0.005Nm3V (t.min) SiO in the inclusions of molten steel246% of CaO component, 30% of Al2O3The content of the components is 6 percent; slag is adopted for slagging, the slag alkalinity of the slag is 2.8, inclusions in molten steel are regulated and controlled through soft stirring, the soft stirring time is 34min, and the flow of argon blown from the bottom of a steel ladle during soft stirring is 0.5L/min t.
The size of the inclusions in the molten steel finally smelted is less than or equal to 15 mu m.
(II) casting stage
And casting the molten steel into a continuous casting billet, adopting an electromagnetic induction heating device to regulate and control the temperature of the molten steel of the tundish, controlling the superheat degree of the tundish to be 18 ℃, the casting drawing speed to be 0.65m/min, controlling the total reduction of the continuous casting billet in the solidification process to be 25mm, and controlling the reduction of 5-11 # withdrawal and straightening machines to be 2mm, 4mm, 5mm, 4mm and 3mm respectively.
The central carbon segregation value of the continuous casting slab is 1.02, and the C content of the segregation region is 1.03%.
(III) cogging stage
And heating the continuous casting billet by a heating furnace, continuously rolling the continuous casting billet to form an intermediate billet, carrying out magnetic powder inspection on the intermediate billet, and grinding the defect part, namely carrying out surface treatment on the intermediate billet after cogging to remove the defect on the surface of the intermediate billet.
(IV) Rolling stage
And rolling the polished intermediate blank into a wire rod with the diameter of 6.0mm through a high wire.
(V) temperature-controlled cooling stage
And carrying out temperature control cooling on the wire rod on a stelmor cooling line, wherein the spinning temperature is 925 ℃, the air volume of a No. 1-4 fan is 100%, the rest fans are closed, the average speed of a roller way is 75m/min, the average cooling speed before pearlite phase transformation is 18 ℃/1, and the average cooling speed during pearlite phase transformation is 5 ℃/1.
(VI) salt bath Heat treatment stage
And heating the wire rod cooled by controlling the temperature in a salt bath heating furnace, then sending the wire rod into a salt bath for rapid cooling, wherein the temperature in the salt bath heating furnace is 967 ℃, the temperature of molten salt is 528 ℃, the wiring speed of the wire rod is 10.7m/min, and collecting coils to finally obtain a finished wire rod product.
The obtained wire rod product was tested for inclusions, texture and mechanical properties, and the results are shown in table 2, including the size of the largest inclusions, the mesh cementite (i.e., the mesh carbon in table 2), the tensile strength and the reduction of area of the wire rod.
(VII) drawing stage
The finished wire rod is drawn into a monofilament with a diameter of 0.2mm, the tensile strength and the breakage rate of the monofilament are detected, and the measured results are shown in table 2.
Comparative example 1
The steel smelting stage comprises the following steps of:
(1) pre-desulphurisation of molten iron
The blast furnace slag in the ladle is removed before desulfurization, the slag removal rate is 75%, the blast furnace molten iron is adopted to carry out desulfurization in a KR desulfurization device, and the blast furnace molten iron meets the following requirements before desulfurization: the temperature is 1350 ℃, C is 4.0%, S is less than or equal to 0.044%, Ti is 0.04%, Si is 0.20%, P is 0.10%, the balance is Fe and other inevitable impurities, and the S content in the molten iron after pre-desulfurization is 0.002%.
(2) Smelting in a converter
Feeding the pretreated molten iron into a converter to be mixed with scrap steel to form molten steel, and carrying out desiliconization, dephosphorization, oxygen blowing and decarburization; wherein the molten iron accounts for 80% of the molten steel, and the scrap steel satisfies the following requirements: the thickness is more than or equal to 1cm, S is less than or equal to 0.02 percent, and P is less than or equal to 0.02 percent; when tapping begins, firstly adding ferrosilicon, metal manganese and 30% of carburant into a ladle for deoxidation alloying, adding the rest carburant when the tapping reaches 85%, and adding lime and synthetic slag for slagging after the tapping is finished; the tapping temperature of the molten steel is 1634 ℃, and the content of C in the molten steel is 0.01% during tapping.
(3) Refining procedure
Carrying out chemical component adjustment and temperature regulation on the molten steel smelted by the converter in an LF (ladle furnace) refining furnace, adding 7kg/t of refining covering agent to the surface of the molten steel, electrifying and melting the refining covering agent, and controlling the intensity of argon blown from the bottom of a steel ladle to be less than or equal to 0.005Nm3V (t.min) SiO in the inclusions of molten steel239% of CaO component, 30% of Al2O3The content of the components is 14 percent; slag is adopted for slagging, the slag alkalinity of the slag is 2.3, inclusions in molten steel are regulated and controlled through soft stirring, the soft stirring time is 26min, and the flow of argon blown from the bottom of a steel ladle during soft stirring is 0.4L/min t.
(II) casting stage
And casting the molten steel into a continuous casting billet, and regulating and controlling the temperature of the molten steel in the tundish by adopting an electromagnetic induction heating device, wherein the superheat degree of the tundish is controlled to be 13 ℃, the casting drawing speed is 0.60m/min, the total reduction in the solidification process of the continuous casting billet is controlled to be 25mm, and the reduction of a No. 5-11 withdrawal and straightening machine is respectively 2mm, 3mm, 6mm, 5mm, 4mm and 3 mm.
(III) cogging stage
And heating the continuous casting billet by a heating furnace, continuously rolling the continuous casting billet to form an intermediate billet, carrying out magnetic powder inspection on the intermediate billet, and grinding the defect part, namely carrying out surface treatment on the intermediate billet after cogging to remove the defect on the surface of the intermediate billet.
(IV) Rolling stage
And rolling the polished intermediate blank into a wire rod with the diameter of 5.5mm through a high wire.
(V) temperature-controlled cooling stage
And carrying out temperature control cooling on the wire rod on a stelmor cooling line, wherein the spinning temperature is 935 ℃, the air quantity of a No. 1-3 fan is 100%, the rest fans are closed, the average speed of a roller way is 73m/min, the average cooling speed before pearlite phase transformation is 18 ℃/1, and the average cooling speed during pearlite phase transformation is 8 ℃/1. And (5) collecting the coil and finally obtaining a finished product of the wire rod.
The obtained wire rod product was tested for inclusions, texture and mechanical properties, and the results are shown in table 2, including the size of the largest inclusions, the mesh cementite (i.e., the mesh carbon in table 2), the tensile strength and the reduction of area of the wire rod.
(VI) drawing stage
The finished wire rod is drawn into a monofilament with a diameter of 0.2mm, the tensile strength and the breakage rate of the monofilament are detected, and the measured results are shown in table 2.
Comparative example 2
The steel smelting stage comprises the following steps of:
(1) pre-desulphurisation of molten iron
The blast furnace slag in the ladle is removed before desulfurization, the slag removal rate is 75%, the blast furnace molten iron is adopted to carry out desulfurization in a KR desulfurization device, and the blast furnace molten iron meets the following requirements before desulfurization: the temperature is 1355 ℃, the C is 4.05 percent, the S is 0.036 percent, the Ti is 0.05 percent, the Si is 0.50 percent, the P is 0.07 percent, the balance is Fe and other inevitable impurities, and the S content in the molten iron after pre-desulfurization is 0.002 percent.
(2) Smelting in a converter
Feeding the pretreated molten iron into a converter to be mixed with scrap steel to form molten steel, and carrying out desiliconization, dephosphorization, oxygen blowing and decarburization; the molten iron accounts for 90% of the molten steel, the scrap steel adopts high-quality scrap steel, and the high-quality scrap steel meets the following requirements: the thickness is more than or equal to 2cm, S is less than or equal to 0.02 percent, and P is less than or equal to 0.02 percent; when tapping begins, firstly adding ferrosilicon, metal manganese and 30% of carburant into a ladle for deoxidation alloying, adding the rest carburant when the tapping reaches 85%, and adding lime and synthetic slag for slagging after the tapping is finished; the tapping temperature of the molten steel is 1636 ℃, and the content of C in the molten steel is 0.01% during tapping.
(3) Refining procedure
Carrying out chemical component adjustment and temperature regulation on molten steel smelted by the converter in an LF (ladle furnace) refining furnace, adding 12kg/t of refining covering agent to the surface of the molten steel, electrifying to melt the refining covering agent, and controlling the argon blowing intensity at the bottom of a steel ladle to be less than or equal to 0.005Nm3V (t.min) SiO in the inclusions of molten steel240% of component, 30% of CaO component, Al2O3The content of the components is 15 percent; slag is adopted for slagging, the slag alkalinity of the slag is 2.2, inclusions in molten steel are regulated and controlled through soft stirring, the soft stirring time is 27min, and the flow of argon blown from the bottom of a steel ladle during soft stirring is 0.9L/min t.
(II) casting stage
And casting the molten steel into a continuous casting billet, and regulating and controlling the temperature of the molten steel in the tundish by adopting an electromagnetic induction heating device, wherein the superheat degree of the tundish is controlled to be 16 ℃, the casting drawing speed is 0.64m/min, the total reduction in the solidification process of the continuous casting billet is controlled to be 22mm, and the reduction of a No. 5-11 withdrawal and straightening machine is respectively 2mm, 3mm, 4mm and 3 mm.
(III) cogging stage
And heating the continuous casting billet by a heating furnace, continuously rolling the continuous casting billet to form an intermediate billet, carrying out magnetic powder inspection on the intermediate billet, and grinding the defect part, namely carrying out surface treatment on the intermediate billet after cogging to remove the defect on the surface of the intermediate billet.
(IV) Rolling stage
And rolling the polished intermediate blank into a wire rod with the diameter of 5.5mm through a high wire.
(V) temperature-controlled cooling stage
And carrying out temperature control cooling on the wire rod on a stelmor cooling line, wherein the spinning temperature is 928 ℃, the air quantity of a No. 1-4 fan is 100%, the rest fans are closed, the average speed of a roller way is 72m/min, the average cooling speed before pearlite phase transformation is 15 ℃/1, and the average cooling speed during pearlite phase transformation is 9 ℃/1. And (5) collecting the coil and finally obtaining a finished product of the wire rod.
The obtained wire rod product was tested for inclusions, texture and mechanical properties, and the results are shown in table 2, including the size of the largest inclusions, the mesh cementite (i.e., the mesh carbon in table 2), the tensile strength and the reduction of area of the wire rod.
(VI) drawing stage
The finished wire rod is drawn into a monofilament with a diameter of 0.2mm, the tensile strength and the breakage rate of the monofilament are detected, and the measured results are shown in table 2.
Comparative example 3
The steel smelting stage comprises the following steps of:
(1) pre-desulphurisation of molten iron
The blast furnace slag in the ladle is removed before desulfurization, the slag removal rate is 84%, the blast furnace molten iron is adopted to carry out desulfurization in a KR desulfurization device, and the blast furnace molten iron meets the following requirements before desulfurization: the temperature is 1370 ℃, C4.0%, S0.03%, Ti 0.03%, Si 0.28%, P0.13%, and the balance Fe and other inevitable impurities, and the content of S in the pre-desulfurized molten iron is 0.0013%.
(2) Smelting in a converter
Feeding the pretreated molten iron into a converter to be mixed with scrap steel to form molten steel, and carrying out desiliconization, dephosphorization, oxygen blowing and decarburization; wherein the molten iron accounts for 91% of the molten steel, and the scrap steel satisfies the following requirements: the thickness is more than or equal to 1cm, S is less than or equal to 0.02 percent, and P is less than or equal to 0.02 percent; when tapping begins, firstly adding ferrosilicon, metal manganese and 30% of carburant into a ladle for deoxidation alloying, adding the rest carburant when the tapping reaches 85%, and adding lime and synthetic slag for slagging after the tapping is finished; the tapping temperature of the molten steel is 1634 ℃, and the content of C in the molten steel is 0.13% during tapping.
(3) Refining procedure
Carrying out chemical component adjustment and temperature regulation on the molten steel smelted by the converter in an LF (ladle furnace) refining furnace, adding 8kg/t of refining covering agent to the surface of the molten steel, electrifying and melting the refining covering agent, and controlling the intensity of argon blown from the bottom of a steel ladle to be less than or equal to 0.005Nm3V (t.min) SiO in the inclusions of molten steel234% of component, 25% of CaO component, Al2O3The content of the components is 25 percent; slag is adopted for slagging, the slag alkalinity of the slag is 2.5, inclusions in molten steel are regulated and controlled through soft stirring, the soft stirring time is 27min, and the flow of argon blown from the bottom of a steel ladle during soft stirring is 0.7L/min t.
(II) casting stage
And casting the molten steel into a continuous casting billet, adopting an electromagnetic induction heating device to regulate and control the temperature of the molten steel of the tundish, controlling the superheat degree of the tundish to be 18 ℃, the casting drawing speed to be 0.65m/min, controlling the total reduction of the continuous casting billet in the solidification process to be 25mm, and controlling the reduction of 5-11 # withdrawal and straightening machines to be 2mm, 4mm, 5mm, 4mm and 3mm respectively.
(III) cogging stage
And heating the continuous casting billet by a heating furnace, continuously rolling the continuous casting billet to form an intermediate billet, carrying out magnetic powder inspection on the intermediate billet, and grinding the defect part, namely carrying out surface treatment on the intermediate billet after cogging to remove the defect on the surface of the intermediate billet.
(IV) Rolling stage
And rolling the polished intermediate blank into a wire rod with the diameter of 5.5mm through a high wire.
(V) temperature-controlled cooling stage
And carrying out temperature control cooling on the wire rod on a stelmor cooling line, wherein the spinning temperature is 938 ℃, the air volume of a No. 1-2 fan is 100%, the rest fans are closed, the average speed of a roller way is 70m/min, the average cooling speed before pearlite phase transformation is 8 ℃/1, and the average cooling speed during pearlite phase transformation is 5 ℃/1. And (5) collecting the coil and finally obtaining a finished product of the wire rod.
The obtained wire rod product was tested for inclusions, texture and mechanical properties, and the results are shown in table 2, including the size of the largest inclusions, the mesh cementite (i.e., the mesh carbon in table 2), the tensile strength and the reduction of area of the wire rod.
(VI) drawing stage
The finished wire rod is drawn into a monofilament with a diameter of 0.2mm, the tensile strength and the breakage rate of the monofilament are detected, and the measured results are shown in table 2.
[ Table 2]
In conclusion, the 102-grade cord wire steel wire rod prepared by the production method of the 102-grade cord wire steel wire rod has the advantages that the size of the largest inclusion is less than or equal to 15 mu m, the grade of the network carbide in the wire rod is within 1 grade, the mechanical property is excellent, the tensile strength can reach more than 1300MPa, the fluctuation of the tensile strength is small, the reduction of area can reach more than 35 percent, and the drawing breakage rate is less than or equal to 2 times per ton. In addition, the wire rod of the embodiment can be further processed into the extra-high strength steel cord with the monofilament tensile strength of more than or equal to 4000MPa through the processes of drawing and the like, and the extra-high strength steel cord is low in drawing broken rate, low in strand twisting broken rate, low in die consumption, high in yield and easy to draw in the deep processing process.
Claims (10)
1. A method for producing a 102-grade cord steel wire rod, characterized in that the method comprises the following stages which are carried out in sequence:
in the steel smelting stage, molten steel with inclusion size less than or equal to 15 microns is smelted;
in the casting blank stage, the molten steel is cast into a continuous casting blank, wherein the central carbon segregation value of the continuous casting blank is less than or equal to 1.05, and the C in a segregation area is less than or equal to 1.09%;
in the cogging stage, the continuous casting billet is heated by a heating furnace and then continuously rolled to form an intermediate billet, the intermediate billet is subjected to magnetic powder inspection, and the defective part is polished;
in the rolling stage, the polished intermediate blank is rolled into a wire rod through a high-speed wire, and the wire rod comprises the following chemical components in percentage by mass: 1.00-1.04% of C, 0.2-0.3% of Si, 0.3-0.4% of Mn, 0.3-0.4% of Cr, less than or equal to 0.0020% of Al, less than or equal to 0.0006% of Ti, less than or equal to 0.003% of S, less than or equal to 0.008% of P, less than or equal to 0.03% of Cu, less than or equal to 0.02% of Ni, less than or equal to 0.0015% of O, less than or equal to 0.0030% of N, and the balance of Fe and other inevitable impurities; wherein, the content of Mn and Si satisfies: Mn/Si is 1.3-1.6;
in the temperature control cooling stage, the wire rod is cooled at a controlled temperature on a stelmor cooling line;
and in the salt bath heat treatment stage, heating the temperature-controlled and cooled wire rod in a salt bath heating furnace, and then sending the wire rod into a salt bath for rapid cooling, wherein the temperature in the salt bath heating furnace is 960-980 ℃, the temperature of the molten salt is 520-540 ℃, and the wiring speed of the wire rod is 10-12 m/min.
2. The method of claim 1, wherein the steel smelting stage comprises the following steps in sequence:
the molten iron is desulfurized in advance, adopts blast furnace molten iron to carry out the desulfurization at KR desulphurization unit, just blast furnace molten iron satisfies before the desulfurization: the temperature is more than or equal to 1360 ℃, the C is 4.0-4.5%, the S is less than or equal to 0.04%, the Ti is less than or equal to 0.04%, the Si is 0.20-0.60%, the P is less than or equal to 0.10%, the balance is Fe and other inevitable impurities, and the S in the molten iron after pre-desulfurization is less than or equal to 0.002%;
smelting in a converter, namely feeding the pretreated molten iron into the converter to be mixed with scrap steel to form molten steel, and carrying out desiliconization, dephosphorization, oxygen blowing and decarburization; the molten iron accounts for 83-88% of the molten steel, the scrap steel adopts high-quality scrap steel, and the high-quality scrap steel meets the following requirements: the thickness is more than or equal to 2cm, S is less than or equal to 0.02 percent, and P is less than or equal to 0.02 percent; the molten steel is deoxidized and alloyed by adding a recarburizing agent, ferrosilicon and manganese metal into a ladle, the tapping temperature of the molten steel is more than or equal to 1640 ℃, and the C in the molten steel is more than or equal to 0.05% during tapping.
A refining process, namely adjusting chemical components and regulating temperature of the molten steel smelted in the converter in an LF (ladle furnace), adding 8-12 kg/t of refining covering agent to the surface of the molten steel, electrifying to melt the refining covering agent, and controlling the intensity of argon blown from the bottom of a steel ladle to be less than or equal to 0.005Nm3V (t.min) SiO in the inclusions of molten steel2The content of the component is more than or equal to 40 percent, the content of the CaO component is less than or equal to 30 percent, and Al2O3The content of the components is less than or equal to 10 percent, the inclusion in the molten steel is regulated and controlled through soft stirring, the soft stirring time is more than or equal to 30min, and the flow of argon blown from the bottom of the steel ladle during soft stirring is 0.5-0.7L/min.t.
3. The method for producing the grade 102 cord steel wire rod according to claim 2, wherein in the refining process, slag is used for slagging, and the slag alkalinity of the slag is 2.5-3.0.
4. The production method of the 102-grade cord steel wire rod according to claim 1, wherein in the casting blank stage, the superheat degree of a tundish is controlled to be 15-20 ℃, the casting pulling speed is 0.64-0.66 m/min, the total reduction is 23-28 mm, and the reduction of a single roller is less than or equal to 5 mm.
5. The production method of the 102-grade cord steel wire rod according to claim 1, wherein in the temperature-controlled cooling stage, the spinning temperature is 910-930 ℃, the air volume of a No. 1-4 blower is 100%, the rest blowers are turned off, the average speed of a roller way is 72-75 m/min, the average cooling speed before pearlite phase transformation is 13-17 ℃/1, and the average cooling speed during pearlite phase transformation is 5-10 ℃/1.
6. A grade 102 cord steel wire rod, characterized in that the wire rod is prepared by the production method of any one of claims 1 to 5.
7. The 102-grade cord steel wire rod is characterized in that the diameter of the wire rod is 5.0-6.5 mm, the tensile strength is not less than 1300MPa, the reduction of area is not less than 35%, and the drawing filament breakage rate is not more than 2 times per ton.
8. The grade 102 cord steel wire rod of claim 6 wherein the largest inclusions are no more than 15 μm in size and the net carbides in the wire rod are no more than grade 1.
9. A grade 102 steel cord prepared from the grade 102 cord steel wire rod according to any one of claims 6 to 8 as a base material.
10. The grade 102 steel cord according to claim 9, wherein the grade 102 steel cord is twisted from monofilaments having a diameter of 0.20mm, the monofilaments are drawn from the grade 102 cord steel wire rod as a base material, and the tensile strength of the monofilaments is not less than 4000 MPa.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113862564A (en) * | 2021-09-16 | 2021-12-31 | 湖南华菱湘潭钢铁有限公司 | Production method of deep-drawing high-carbon steel wire rod |
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| WO2023071299A1 (en) * | 2021-10-26 | 2023-05-04 | 南京钢铁股份有限公司 | Steel for steel cord having tensile strength greater than or equal to 4,000 mpa and production method |
| CN116117095A (en) * | 2023-01-06 | 2023-05-16 | 江苏省沙钢钢铁研究院有限公司 | High-carbon steel wire rod and preparation method thereof |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011126073A1 (en) * | 2010-04-08 | 2011-10-13 | 新日本製鐵株式会社 | Wire material for saw wire and method for producing same |
| JP2017193732A (en) * | 2016-04-18 | 2017-10-26 | 新日鐵住金株式会社 | Hot-rolled wire rod for high strength steel wire and production method therefor |
| CN110629132A (en) * | 2019-09-26 | 2019-12-31 | 江苏省沙钢钢铁研究院有限公司 | Wire rod for ultra-high strength steel cord and method for producing same |
| CN112176258A (en) * | 2020-09-30 | 2021-01-05 | 江苏省沙钢钢铁研究院有限公司 | Wire rod for 2500 MPa-grade steel strand and manufacturing method thereof |
| CN113088798A (en) * | 2021-03-31 | 2021-07-09 | 江苏省沙钢钢铁研究院有限公司 | High-carbon steel wire rod and production method thereof |
-
2021
- 2021-12-28 CN CN202111624479.2A patent/CN114318149A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011126073A1 (en) * | 2010-04-08 | 2011-10-13 | 新日本製鐵株式会社 | Wire material for saw wire and method for producing same |
| JP2017193732A (en) * | 2016-04-18 | 2017-10-26 | 新日鐵住金株式会社 | Hot-rolled wire rod for high strength steel wire and production method therefor |
| CN110629132A (en) * | 2019-09-26 | 2019-12-31 | 江苏省沙钢钢铁研究院有限公司 | Wire rod for ultra-high strength steel cord and method for producing same |
| CN112176258A (en) * | 2020-09-30 | 2021-01-05 | 江苏省沙钢钢铁研究院有限公司 | Wire rod for 2500 MPa-grade steel strand and manufacturing method thereof |
| CN113088798A (en) * | 2021-03-31 | 2021-07-09 | 江苏省沙钢钢铁研究院有限公司 | High-carbon steel wire rod and production method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 段建华: "《钢丝技术》", 31 March 2020, 苏州大学出版社 * |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113862564A (en) * | 2021-09-16 | 2021-12-31 | 湖南华菱湘潭钢铁有限公司 | Production method of deep-drawing high-carbon steel wire rod |
| WO2023071299A1 (en) * | 2021-10-26 | 2023-05-04 | 南京钢铁股份有限公司 | Steel for steel cord having tensile strength greater than or equal to 4,000 mpa and production method |
| CN115247240A (en) * | 2022-09-21 | 2022-10-28 | 张家港荣盛特钢有限公司 | Hypereutectoid spring steel wire rod and manufacturing method thereof |
| CN116117095A (en) * | 2023-01-06 | 2023-05-16 | 江苏省沙钢钢铁研究院有限公司 | High-carbon steel wire rod and preparation method thereof |
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| CN116891977A (en) * | 2023-09-04 | 2023-10-17 | 江苏永钢集团有限公司 | Wire rod for extra-high-strength diamond wire bus and production method thereof |
| CN116891977B (en) * | 2023-09-04 | 2023-11-21 | 江苏永钢集团有限公司 | Wire rod for extra-high-strength diamond wire bus and production method thereof |
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