Cutting steel wire, steel material for cutting steel wire, and method for producing same
Technical Field
The invention belongs to the technical field of steel smelting, and relates to a production method of steel for a cutting steel wire, the steel for the cutting steel wire prepared by the production method, and the cutting steel wire further processed by the steel for the cutting steel wire.
Background
The cutting steel wire, also called cutting wire, cutting steel wire, cutting wire, is a special wire rod for cutting, also a special steel wire with the diameter less than 0.20mm and the surface of galvanized copper, which is widely used in the fields of energy, aviation, equipment and public facilities as a consumable material, such as the cutting and forming of solar silicon wafers, quartz materials, monocrystalline silicon and polycrystalline silicon. Even the tiny diamond particles can be embedded on the cutting steel wire to be made into a diamond cutting wire, or the diamond cutting wire is called a diamond wire, a diamond cutting wire and a diamond wire.
In order to reduce the loss of the material to be cut, such as silicon material, during the cutting process, the properties of the cutting wire are developed toward a smaller diameter, a longer continuous wire length and a higher strength, which are affected by the inclusion of the steel material for the cutting wire and the tensile strength. In view of the problems of large size of inclusions, large quantity density of inclusions, low tensile strength and the like of the steel for the cutting steel wire prepared by the production process in the technical field, the performance of the existing cutting steel wire can not meet the market demand.
Disclosure of Invention
In order to solve at least one of the above problems, an object of the present invention is to provide a method for producing a steel material for a cutter wire, a steel material for a cutter wire produced by the production method, and a cutter wire further processed from the steel material for a cutter wire.
In order to accomplish one of the above objects, an embodiment of the present invention provides a method for producing a steel material for a cutter wire, the method comprising,
pretreatment: desulfurizing the molten iron until S in the molten iron is less than or equal to 0.002 percent;
blowing: mixing the pretreated molten iron and scrap steel to form molten steel, desiliconizing and dephosphorizing the molten steel at the temperature of 1330-1380 ℃, then blowing oxygen to decarbonize the molten steel, and after slag stopping and tapping, obtaining the molten steel with the temperature of more than or equal to 1650 ℃, the temperature of more than or equal to 0.3 percent of C, the temperature of less than or equal to 0.01 percent of P and the temperature of less than or equal to 0.01 percent of S;
and (3) deoxidation alloying: adding a deoxidizer and a slagging agent into the blown molten steel;
refining: the molten steel after deoxidation alloying is subjected to chemical component adjustment and inclusion regulation, and the inclusion in the refined molten steel comprises the following components: al (Al)2O3≤10%、CaO≤30%;
Vacuum refining: degassing the refined molten steel and removing impurities, wherein the vacuum refined molten steel meets the following requirements: c is more than or equal to 0.90 percent and less than or equal to 1.15 percent, Si is more than or equal to 0.4 percent and less than or equal to 0.4 percent, Mn is more than or equal to 0.6 percent and less than or equal to 0.3 percent, Cr is more than or equal to 0.1 percent and less than or equal to 0.3 percent, P is less than or equal to 0.01 percent, S is less than or equal to 0.01 percent, Al is less than or equal to 0.002 percent, Ti is less than or equal to 0.001 percent, N is less than or equal to 0.003 percent, H is less than or3;
Casting: and casting the molten steel after vacuum refining into a steel billet.
Thus, according to the production method of one embodiment of the invention, on one hand, the precise control of the chemical composition of the steel is realized through operations such as desulfurization, desilicication, dephosphorization, oxygen blowing decarburization, deoxidation alloying, chemical composition adjustment, degassing and the like; on the other hand, the slag is formed in the blowing process, the deoxidation alloying process and the refining process, so that the component control of the impurities is realized, the removal degree of the impurities is increased (namely, the size and the number density of the impurities are reduced), the chemical components and the impurities are effectively and accurately controlled finally, the performance of the steel for the cutting steel wire is ensured, and the ultra-small diameter, the ultra-high tensile strength and the ultra-long continuous wire breakage mileage of the cutting steel wire are further ensured
As a further improvement of an embodiment of the present invention, in the pretreatment step: adopt 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 1350 ℃, Si is more than or equal to 0.25% and less than or equal to 0.45%, and S is less than or equal to 0.04%. The desulfurization effect of the pretreatment process can be ensured by optimizing the temperature and the components of the equipment and the blast furnace molten iron.
As a further improvement of one embodiment of the invention, the slagging agent is added in the blowing process in batches, and the total adding amount of the slagging agent is 35-50 Kg/ton of molten steel. The slag former is added in batches, and the addition of the slag former is optimized, so that the slag forming effect in the blowing process is ensured, and the components, the size and the number density of the inclusions in the finally prepared steel material for the cutting steel wire are further ensured to be optimized.
As a further improvement of an embodiment of the present invention, the slag former is divided into at least 3 batches;
in the converting process: mixing the pretreated molten iron and waste steel into molten steel, adding the 1 st batch of slag former into the molten steel, desiliconizing and dephosphorizing the molten steel at 1330-1380 ℃, adding the 2 nd batch of slag former into the desiliconized and dephosphorized molten steel, then blowing oxygen for decarbonization of the molten steel, and adding the 3 rd batch of slag former into the oxygen blowing decarbonization process. By regulating and controlling the addition nodes of each batch of the slag former, the desiliconization, dephosphorization, decarburization and slagging effects are ensured, and the chemical components and the inclusion condition in the finally prepared steel for the cutting steel wire are optimized.
As a further improvement of an embodiment of the present invention, in the converting step: adding scrap steel into a converter, adding pretreated molten iron into the converter according to the proportion of 90-95%, desiliconizing and dephosphorizing the molten steel at 1330-1380 ℃ for 3-15 minutes, and then blowing oxygen to decarbonize the molten steel; or,
in the converting process: adding scrap steel into an electric furnace, adding pretreated molten iron into the electric furnace according to the proportion of 60-90%, desilicifying and dephosphorizing the molten steel at 1330-1380 ℃ for 3-15 minutes, blowing oxygen to decarbonize the molten steel, and electrifying to heat up when the temperature of the molten steel does not reach a preset value;
wherein the scrap steel satisfies: less than or equal to 0.02 percent of S, less than or equal to 0.05 percent of Cu, less than or equal to 0.05 percent of Ni and less than or equal to 0.02 percent of Ti.
Therefore, by adopting the clean scrap steel and accurately regulating and controlling the smelting temperature and the smelting time of the electric furnace or the converter, the chemical components in the steel for finally cutting the steel wire can more accurately meet the target requirements.
As a further improvement of an embodiment of the present invention, in the deoxidation alloying step: sequentially adding a deoxidizer and a slagging constituent into the blown molten steel; wherein the deoxidizer comprises a recarburizer, a ferrosilicon alloy and metal manganese which are sequentially added into the molten steel, and the slagging agent is Al with the alkalinity of 0.8-1.22O3Less than or equal to 10 percent of premelted refining slag. By adopting the low-alkalinity acid slag system, the control of Al in the composition of impurities in molten steel is facilitated2O3The content is less than or equal to 10 percent, the CaO content is less than or equal to 30 percent, and the high SiO2 silicate inclusions are mainly used, so that the inclusions are convenient to aggregate, grow and float upwards to remove.
As a further improvement of an embodiment of the present invention, in the refining step: sending the molten steel after deoxidation alloying into an LF furnace for electrifying and heating, chemical component adjustment and inclusion regulation, wherein the inclusion in the refined molten steel comprises the following components: al (Al)2O3≤10%、CaO≤30%。
As a further improvement of an embodiment of the present invention, in the vacuum refining step: keeping the refined molten steel at a vacuum degree of less than or equal to 1.5mbar for at least 15 minutes to carry out vacuum degassing and inclusion removal;
wherein, in the vacuum refining step: feeding the refined molten steel into an RH furnace, and keeping the molten steel for 15-20 minutes under the condition that the vacuum degree is less than or equal to 1.5mbar to perform vacuum degassing and impurity removal; or,
in the vacuum refining process: sending the refined molten steel into a VD furnace or a VOD furnace, keeping the molten steel for 20-30 minutes under the condition that the vacuum degree is less than or equal to 1.5mbar for vacuum degassing and removing inclusions, and simultaneously blowing argon gas at the bottom of the steel ladle with the intensity less than or equal to 0.003Nm3/(t · min). The removal effect of N, H and inclusions is ensured by optimizing the vacuum degree, the vacuum treatment time and the strength of bottom blowing argon, so that the cleanliness of the finally prepared steel for the cutting steel wire is further ensured.
As a further improvement of an embodiment of the present invention, in the casting step: molten steel after vacuum refining is sent to a continuous casting machine to be cast into a continuous casting billet, so that the production efficiency can be improved and large-scale production is facilitated.
As a further improvement of an embodiment of the present invention, the production method further includes,
a steel rolling procedure: and carrying out steel rolling on the steel billet at the temperature of 950-1200 ℃ to prepare the wire rod. Thus, the wire rod for the cutting steel wire with the tensile strength of more than or equal to 1300MPa can be obtained by the production method.
Preferably, in the steel rolling process: and carrying out steel rolling on the steel billet at the temperature of 980-1050 ℃ to prepare a wire rod with the diameter of 5-10 mm. The thickness of the decarburized layer is favorably controlled by further optimizing the rolling temperature, so that the performance of the wire rod is ensured.
In order to achieve one of the above objects, an embodiment of the present invention also provides a steel material for a cutting wire, which is prepared by the production method. The steel for the cutting steel wire can be used as a base material for producing the cutting steel wire with the diameter less than or equal to 100 mu m and the tensile strength more than or equal to 4600MPa, specifically can be a billet for the cutting steel wire or a wire rod for the cutting steel wire, and the mileage of continuous wire breakage can be more than or equal to 200km in the process of further manufacturing the steel for the cutting steel wire into the cutting steel wire.
Accordingly, in order to achieve one of the above objects, an embodiment of the present invention further provides a cutting wire, which is made of the steel material for cutting wires. Preferably, the diameter of the cutting steel wire is less than or equal to 100 mu m, the tensile strength is more than or equal to 4600MPa, and the continuous filament mileage in the drawing preparation process is more than or equal to 200km, so that the requirements of the current industry on the diameter, the continuous filament mileage and the strength of the cutting steel wire can be met, and the large-scale production of the cutting steel wire can be realized.
Drawings
Fig. 1 is a flowchart of a method for producing a steel material for a cutter wire according to an embodiment of the present invention.
Detailed Description
An embodiment of the invention provides a production method of a steel material for a cutter wire and the steel material for the cutter wire prepared by the production method. The steel material for a cutter wire obtained has different expressions according to the termination process of the production process actually performed by the production method, for example, as shown in fig. 1, and preferably, the production method includes the steps of pretreatment, blowing, deoxidation alloying, refining, vacuum refining, casting, and rolling, which are performed in this order, and the steel material for a cutter wire is realized in a wire rod manner (thus, also referred to as a wire rod for a cutter wire); of course, in other embodiments, if the termination step is the casting step, the steel material for a cutter wire is realized as a billet (also referred to as a billet for a cutter wire in this case).
The respective steps in the production method will be described in detail with reference to fig. 1.
(1) The pretreatment step
And desulfurizing the molten iron until S in the molten iron is less than or equal to 0.002 percent.
Preferably, the blast furnace molten iron is adopted to carry out desulphurization in a KR desulphurization device, and the blast furnace molten iron meets the following requirements before desulphurization: the temperature is more than or equal to 1350 ℃, Si is more than or equal to 0.25% and less than or equal to 0.45%, and S is less than or equal to 0.04%.
(2) The converting step
Mixing the pretreated molten iron and scrap steel to form molten steel, desiliconizing and dephosphorizing the molten steel at the temperature of 1330-1380 ℃, then blowing oxygen to decarbonize the molten steel, and finally stopping slag and tapping to obtain the molten steel with the temperature of more than or equal to 1650 ℃, the temperature of more than or equal to 0.3 percent of C, the temperature of less than or equal to 0.01 percent of P and the temperature of less than or equal to 0.01 percent of S.
Further, the converting process may be carried out in a converter or an electric furnace: for example, adding scrap steel into a converter, adding pretreated molten iron into the converter according to the proportion of 90-95%, desiliconizing and dephosphorizing the molten steel at 1330-1380 ℃ for 3-15 minutes, and then blowing oxygen to decarbonize the molten steel; or, for example, adding scrap steel into an electric furnace, adding pretreated molten iron into the electric furnace according to the proportion of 60-90%, desiliconizing and dephosphorizing the molten steel at 1330-1380 ℃ for 3-15 minutes, blowing oxygen to decarbonize the molten steel, and electrifying to heat the molten steel when the temperature of the molten steel does not reach a preset value.
It should be noted that the "proportion" in the above description of "the pretreated molten iron is 90% to 95%", "the pretreated molten iron is 60% to 90%", and the like means the weight proportion of the molten iron charged into the converter or the electric furnace to the molten steel mixed by the charged molten iron and the scrap.
In addition, the scrap is preferably arranged to be clean scrap, i.e. to satisfy: less than or equal to 0.02 percent of S, less than or equal to 0.05 percent of Cu, less than or equal to 0.05 percent of Ni and less than or equal to 0.02 percent of Ti.
Furthermore, the blowing process is divided into batches, and the total adding amount of the slag former is 35 to 50 Kg/ton of molten steel, for example, if the total amount of the molten steel is 100t, the total adding amount of the slag former is 35 to 50 Kg/ton of molten steel 100t in the blowing process, and the slag former is added into the molten steel in several batches. For example, preferably, the slag former is divided into at least 3 batches: the method comprises the following steps of mixing pretreated molten iron and scrap steel into molten steel in the 1 st batch, adding the molten steel in the 2 nd batch after desiliconization and dephosphorization and before oxygen decarburization, and adding the molten steel in the 3 rd batch in the oxygen decarburization process (specifically, after 3-6 minutes from the start of oxygen decarburization).
As an alternative, the slag former in the converting process can be designed as follows: CaO 25-45%, SiO2:35-55%,Al2O3Less than or equal to 10 percent, less than or equal to 6 percent of MgO and other inevitable impurities.
(3) The deoxidation alloying procedure
And adding a deoxidizer and a slag former into the blown molten steel to perform deoxidation alloying at least.
Preferably, the molten steel after blowing is sequentiallyAdding a deoxidizer and a slagging agent; wherein the deoxidizer comprises a recarburizer, a ferrosilicon alloy and metal manganese which are sequentially added into the blown molten steel, and the slagging agent is Al with the alkalinity of 0.8-1.22O3Less than or equal to 10 percent of premelted refining slag.
(4) The refining step
And (3) carrying out chemical component adjustment on the molten steel after deoxidation alloying, wherein the components of inclusions in the molten steel after refining are as follows: al (Al)2O3Less than or equal to 10 percent and less than or equal to 30 percent of CaO. That is, the refined molten steel is a low-basicity acidic slag system.
Preferably, the molten steel after deoxidation alloying is sent into an LF furnace for electrifying temperature rise, chemical composition adjustment and inclusion regulation. Wherein, the chemical composition can be adjusted by adding chemical elements according to the required components of the final molten steel.
(5) The vacuum refining step
Degassing the refined molten steel and removing impurities, wherein the vacuum refined molten steel meets the following requirements: c is more than or equal to 0.90 percent and less than or equal to 1.15 percent, Si is more than or equal to 0.4 percent and less than or equal to 0.4 percent, Mn is more than or equal to 0.6 percent and less than or equal to 0.3 percent, Cr is more than or equal to 0.1 percent and less than or equal to 0.3 percent, P is less than or equal to 0.01 percent, S is less than or equal to 0.01 percent, Al is less than or equal to 0.002 percent, Ti is less than or equal to 0.001 percent, N is less than or equal to 0.003 percent, H is less than or3。
Further, in the vacuum refining step: and keeping the refined molten steel at the vacuum degree of less than or equal to 1.5mbar for at least 15 minutes to perform vacuum degassing and inclusion removal. Specifically, the vacuum refining process may be performed in an RH furnace, or a VD furnace, or a VOL furnace: for example, the refined molten steel is sent into an RH furnace and kept for 15-20 minutes under the condition that the vacuum degree is less than or equal to 1.5mbar so as to carry out vacuum degassing and inclusion removal; or, for example, the refined molten steel is sent into a VD furnace or a VOD furnace, vacuum degassing and inclusion removal are carried out by keeping the refined molten steel for 20-30 minutes under the condition that the vacuum degree is less than or equal to 1.5mbar, and the intensity of argon blown from the bottom of the ladle is less than or equal to 0.003Nm3/(t·min)。
(6) The casting process
And casting the molten steel after vacuum refining into a steel billet.
Preferably, the molten steel after vacuum refining is sent to a continuous casting machine to be cast into a continuous casting billet. Still preferably, the billet or the continuous casting billet can be a small square billet, a large square billet, a rectangular billet or a round billet, and is further preferably a large square billet and a large round billet, the preferred size of the large square billet is 280mm × 280 mm-600 mm × 600mm, and the preferred diameter range of the large round billet is 380 mm-600 mm.
(7) Said steel rolling process
And (3) rolling the steel billet obtained in the casting process at 950-1200 ℃ (namely the temperature in the steel rolling process does not exceed the range of 950-1200 ℃), and preparing the steel billet into a wire rod. Further, the steel billet is rolled at the temperature of 980-1050 ℃ to prepare a wire rod with the diameter of 5-10 mm, wherein the steel rolling process can comprise billet heating, hot rolling, stelmor cooling control and other processes. Of course, without being limited thereto, other steel rolling processes such as disclosed in publication No. CN108998732A may be used to roll the steel blank into wire rods.
Further, the steel material for a cutter wire according to the present invention (including the billet for a cutter wire and the wire rod for a cutter wire) comprises, as chemical components: c is more than or equal to 0.90 percent and less than or equal to 1.15 percent, Si is more than or equal to 0.4 percent and less than or equal to 0.4 percent, Mn is more than or equal to 0.6 percent and less than or equal to 0.3 percent, Cr is more than or equal to 0.1 percent and less than or equal to 0.3 percent, P is less than or equal to 0.01 percent, S is less than or equal to 0.01 percent, Al is less than or equal to 0.002 percent, Ti is less than or equal to 0.001 percent. And the size of the inclusions in the steel material for the cutter wire is less than or equal to 10 mu m, and the number density of the inclusions is less than or equal to 0.5g/m3And the inclusions are: al (Al)2O3Less than or equal to 10 percent and less than or equal to 30 percent of CaO. In addition, a large number of experimental studies prove that the tensile strength of the steel for the cutting steel wire is more than or equal to 1300 MPa.
The steel material for the cutting steel wire can be used as a bus for producing the cutting steel wire with the diameter less than or equal to 100 mu m and the tensile strength more than or equal to 4600MPa, and the mileage of the continuous wire breakage can be more than or equal to 200km in the process of drawing the steel material for the cutting steel wire into the cutting steel wire with the diameter less than or equal to 100 mu m.
In another aspect, an embodiment of the present invention further provides a steel material for a cutter wire, for example, the steel material for a cutter wire (also referred to as a wire rod for a cutter wire) obtained by the example shown in fig. 1, and the steel material for a cutter wire is further subjected to a drawing process to obtain the cutter wire. The diameter of the cutting steel wire is less than or equal to 100 mu m, the tensile strength is more than or equal to 4600MPa, and the mileage of the continuous wire is more than or equal to 200km in the drawing preparation process.
In summary, compared with the prior art, the invention has the following beneficial effects:
(1) on one hand, the precise control of the chemical components of the steel is realized through the operations of desulfurization, desiliconization, dephosphorization, oxygen blowing decarburization, deoxidation alloying, chemical component adjustment, degassing and the like; on the other hand, the slag is formed in the blowing process, the deoxidation alloying process and the refining process, so that the component control of the inclusion is realized, and the removal degree of the inclusion is increased (namely, the size and the number density of the inclusion are reduced), so that the chemical components and the inclusion are effectively and accurately controlled finally, the performance of the steel for the cutting steel wire is ensured, and the ultra-small diameter, the ultra-high tensile strength and the ultra-long continuous wire breakage mileage of the cutting steel wire are further ensured;
(2) by optimizing the addition amount and the addition mode of the slagging agent in the converting process, the components and the addition sequence of the deoxidizer and the slagging agent in the deoxidation alloying process and the like, the control on the components of the inclusions can be further ensured, the removal degree of the inclusions is enhanced, and the performance of the steel for cutting steel wires is further ensured;
(3) the production process of the steel for the cutting steel wire does not need special steel plant equipment, and the production can be completed by common steel-making equipment comprising a blast furnace, a KR desulphurization device, a converter or an electric furnace, an LF furnace, an RH furnace or a VD furnace or a VOD furnace, a continuous casting machine, a steel rolling device and the like, so that the production cost is greatly reduced, and the large-scale production is realized.
As mentioned above, the production method of the present invention is obtained by a large number of experimental studies, and is further illustrated below by specific examples.
Example 1
Five test examples, each having a number of A, B, C, D, E, are illustrated in this example, and specific details of this example are described below.
(1) Pretreatment of
The blast furnace molten iron is taken and desulfurized in a KR desulfurization device, and the temperature, the weight, the Si content and the S content of the blast furnace molten iron and the information of the S content in the desulfurized molten iron are shown in Table 1.
[ Table 1]
(2) Electric furnace converting
Adding scrap steel and pretreated molten iron into a 100t electric furnace, and mixing the scrap steel and the pretreated molten iron into molten steel with the total weight of 110 +/-2 t; adding the 1 st batch of slag former into the molten steel, and then carrying out desiliconization and dephosphorization; adding a 2 nd batch of slagging agent into the desiliconized and dephosphorized molten steel; then, carrying out oxygen blowing decarburization on the molten steel, adding a 3 rd batch of slagging agent in the oxygen blowing decarburization process (specifically, the oxygen blowing decarburization process can be started for about 3-6 minutes), and electrifying to heat up the molten steel if the temperature of the molten steel does not reach a preset value; and finally, slag stopping and tapping. Wherein the scrap steel satisfies: less than or equal to 0.02 percent of S, less than or equal to 0.05 percent of Cu, less than or equal to 0.05 percent of Ni and less than or equal to 0.02 percent of Ti.
In addition, the total addition amount of the slag former, the desiliconization and dephosphorization temperature, the desiliconization and dephosphorization duration, the tapping temperature, the tapping C content, the tapping S content and the tapping P content in the electric furnace converting process are shown in Table 2.
[ Table 2]
(3) Deoxidation alloying and refining
Sequentially adding a deoxidizer and a slagging agent into the blown molten steel for deoxidation alloying and slagging, wherein the deoxidizer comprises a recarburizer, a ferrosilicon alloy and metal manganese which are sequentially added into the blown molten steel, and the slagging agent is Al with the alkalinity shown in Table 32O3Less than or equal to 10 percent of premelted refining slag.
Then, the molten steel after deoxidation alloying is sent into an LF furnace for electrifying temperature rise, chemical composition adjustment and inclusion regulation and control, and Al in the inclusion components in the molten steel after refining is controlled2O3The contents and CaO content are shown in Table 3.
[ Table 3]
(4) Vacuum refining
And (3) feeding the refined molten steel into an RH furnace or a VD furnace or a VOD furnace, and performing vacuum degassing and inclusion removal under the condition of controlling the vacuum degree and the vacuum time, wherein if the refined molten steel is fed into the VD furnace or the VOD furnace, argon is blown from the bottom of the steel ladle. In the vacuum refining step, the furnace type, the degree of vacuum, the vacuum time, the intensity of bottom-blown argon, and other information are shown in table 4;
[ Table 4]
Serial number
|
Furnace shape
|
Vacuum degree, mbar
|
Vacuum time, min
|
Intensity of bottom blown argon, Nm3/(t·min)
|
A
|
RH
|
0.5
|
18
|
/
|
B
|
VD
|
0.7
|
20
|
0.0030
|
C
|
VOD
|
1.5
|
30
|
0.0025
|
D
|
RH
|
1.5
|
15
|
/
|
E
|
RH
|
1.1
|
20
|
/ |
The detection shows that the N content and the H content in the molten steel after vacuum refining are obviously reduced, the size of the inclusions is reduced, and the number density is reduced. Specifically, the chemical composition of molten steel after vacuum refining, the size of inclusions, the number density of inclusions, and other information are shown in table 5.
[ Table 5]
(5) Casting of
And (3) sending the molten steel after vacuum refining to a billet continuous casting machine or a bloom continuous casting machine for casting to obtain continuous casting billets with qualified surface quality and center quality, wherein the section sizes of the continuous casting billets are shown in table 6.
[ Table 6]
Serial number
|
Cross-sectional dimension of continuous casting slab
|
A
|
Small square billet 160mm x 160mm
|
B
|
280mm multiplied by 280mm of large square billet
|
C
|
600mm x 600mm of bloom
|
D
|
Small square billet 160mm x 160mm
|
E
|
400mm x 400mm of bloom |
(6) Rolled steel
The steel rolling process employs a rolling process including billet heating, hot rolling, stelmor cooling control, and the like, and the continuous cast slab prepared in the casting process is rolled at a rolling temperature as shown in table 7 to prepare a wire rod. And the prepared wire rod is measured and the performance is detected, and the information of the wire rod such as the diameter, the tensile strength and the like is shown in a table 7; and further performing deep processing on the wire rod, drawing the wire rod into a cutting steel wire, measuring and detecting the performance of the cutting steel wire, wherein the information of the diameter, the tensile strength, the drawing kilometer number (namely the continuous filament mileage when the wire rod is drawn into the cutting steel wire) and the like of the cutting steel wire are also shown in table 7.
[ Table 7]
Example 2:
five test examples, each having a number of H, I, J, K, L, are illustrated in this example, and specific details of this example are described below.
(1) Pretreatment of
The blast furnace molten iron was taken and desulfurized in a KR desulfurization apparatus, and the temperature, weight, Si content, S content of the blast furnace molten iron and the information on the S content in the desulfurized molten iron are shown in table 8.
[ Table 8]
(2) Converter blowing
Adding scrap steel and pretreated molten iron into a 120t converter, and mixing the scrap steel and the pretreated molten iron into molten steel with the total weight of 130 +/-2 t; adding the 1 st batch of slag former into the molten steel, and then carrying out desiliconization and dephosphorization; adding a 2 nd batch of slagging agent into the desiliconized and dephosphorized molten steel; then, oxygen blowing decarburization is carried out on the molten steel, and a 3 rd batch of slagging agent is added in the oxygen blowing decarburization process (specifically, about 3-6 minutes after the oxygen blowing decarburization begins); and finally, slag stopping and tapping. Wherein the scrap steel satisfies: less than or equal to 0.02 percent of S, less than or equal to 0.05 percent of Cu, less than or equal to 0.05 percent of Ni and less than or equal to 0.02 percent of Ti.
In addition, the total addition amount of the slag former, the desiliconization and dephosphorization temperature, the desiliconization and dephosphorization duration, the tapping temperature, the tapping C content, the tapping S content and the tapping P content in the converter blowing process are shown in table 9.
[ Table 9]
(3) Deoxidation alloying and refining
Sequentially adding a deoxidizing agent and a slagging agent into the blown molten steel for deoxidizing alloying and slagging, wherein the deoxidizing agent comprises a recarburizer, a ferrosilicon alloy and gold which are sequentially added into the blown molten steelBelongs to manganese, the slag former is alkalinity as shown in Table 3 and Al2O3Less than or equal to 10 percent of premelted refining slag.
Then, the molten steel after deoxidation alloying is sent into an LF furnace for electrifying temperature rise, chemical composition adjustment and inclusion regulation and control, and Al in the inclusion components in the molten steel after refining is controlled2O3The contents and CaO content are shown in Table 10.
[ Table 10]
Serial number
|
Alkalinity of premelted refining slag
|
Al2O3Content, wt%
|
CaO content in wt%
|
A
|
0.85
|
8.3
|
16
|
B
|
1.20
|
10.0
|
30
|
C
|
0.95
|
9.2
|
23
|
D
|
0.80
|
7.6
|
22
|
E
|
1.15
|
9.4
|
28 |
(4) Vacuum refining
And (3) feeding the refined molten steel into an RH furnace or a VD furnace or a VOD furnace, and performing vacuum degassing and inclusion removal under the condition of controlling the vacuum degree and the vacuum time, wherein if the refined molten steel is fed into the VD furnace or the VOD furnace, argon is blown from the bottom of the steel ladle. In the vacuum refining step, the furnace type, the degree of vacuum, the vacuum time, the intensity of bottom-blown argon, and other information are shown in table 11;
[ Table 11]
Serial number
|
Furnace shape
|
Vacuum degree, mbar
|
Vacuum time, min
|
Intensity of bottom blown argon, Nm3/(t·min)
|
A
|
RH
|
1.5
|
20
|
/
|
B
|
VD
|
0.5
|
30
|
0.0023
|
C
|
VOD
|
0.9
|
20
|
0.0030
|
D
|
VD
|
1.5
|
23
|
0.0028
|
E
|
VOD
|
1.2
|
26
|
0.0020 |
The detection shows that the N content and the H content in the molten steel after vacuum refining are obviously reduced, the size of the inclusions is reduced, and the number density is reduced. Specifically, the chemical composition of molten steel after vacuum refining, the size of inclusions, the number density of inclusions, and other information are shown in table 12.
[ Table 12]
(5) Casting of
And (3) sending the molten steel after vacuum refining to a large round billet continuous casting machine or a rectangular billet continuous casting machine for casting to obtain continuous casting billets with qualified surface quality and center quality, wherein the section sizes of the continuous casting billets are shown in a table 13.
[ Table 13]
Serial number
|
Cross-sectional dimension of continuous casting slab
|
A
|
Rectangular blank 290mm is multiplied by 320mm
|
B
|
The diameter of the large round billet is 380mm
|
C
|
Diameter of large round billet is 600mm
|
D
|
The diameter of the large round billet is 460mm
|
E
|
Rectangular blank 290mm is multiplied by 320mm |
(6) Rolled steel
The steel rolling process employs a rolling process including billet heating, hot rolling, stelmor cooling control, and the like, and the continuous cast slab prepared in the casting process is rolled at a rolling temperature as shown in table 14 to prepare a wire rod. The prepared wire rod is measured and the performance is detected, and the information of the wire rod such as the diameter, the tensile strength and the like is shown in a table 14; and further performing deep processing on the wire rod, drawing the wire rod into a cutting steel wire, measuring and detecting the performance of the cutting steel wire, wherein the information of the diameter, the tensile strength, the drawing kilometer number (namely the continuous filament mileage when the wire rod is drawn into the cutting steel wire) and the like of the cutting steel wire are also shown in table 14.
[ Table 14]