CN108220769B

CN108220769B - Zirconium-added high-carbon pure steel intermediate frequency induction furnace smelting preparation method

Info

Publication number: CN108220769B
Application number: CN201711348426.6A
Authority: CN
Inventors: 潘孝定; 罗俊义; 王德洪; 叶超; 王璞
Original assignee: Advanced Technology and Materials Co Ltd
Current assignee: Advanced Technology and Materials Co Ltd
Priority date: 2017-12-15
Filing date: 2017-12-15
Publication date: 2020-06-09
Anticipated expiration: 2037-12-15
Also published as: CN108220769A

Abstract

The invention belongs to the technical field of special steel and smelting thereof, and relates to a method for smelting and preparing zirconium-added high-carbon pure steel in a medium-frequency induction furnace. The zirconium-added high-carbon pure steel comprises the following components in percentage by mass: 0.67-0.75% of C, 0.15-0.37% of Si, 0.30-0.80% of Mn, less than or equal to 0.012% of P, less than or equal to 0.006% of S, 0.20-0.50% of Cr, less than or equal to 0.30% of Mo, less than or equal to 0.30% of V, 0.002-0.100% of Zr, and the balance of Fe and inevitable impurities. The preparation method comprises the following steps: smelting in a medium frequency induction furnace, refining in an LF furnace, continuous casting treatment and the like. The mechanical property of the product prepared by the invention is greatly improved compared with the existing product, and the tensile strength Rm is more than or equal to 1400 MPa; the yield strength R0.2 is more than or equal to 1300MPa, the plate is used for sintering the saw blade mother plate, the plastic deformation damage is small, the service life is prolonged, and the production cost of the steel is low.

Description

Zirconium-added high-carbon pure steel intermediate frequency induction furnace smelting preparation method

Technical Field

The invention belongs to the technical field of special steel and smelting thereof, and relates to a method for smelting and preparing zirconium-added high-carbon pure steel in a medium-frequency induction furnace.

Background

At present, when a steel plate is used for sintering a plate such as a saw blade, the steel plate needs to be heated to a certain temperature (about 750 ℃) in the processing process, the use environment is severe, and the material needs to bear strong tensile force and fatigue failure. At present, if the carbon steel plate is used, the sintered plate is easy to generate plastic deformation and has short service life; the use of high strength alloy steel plates is costly. Although the high-quality carbon structural steel No. 70 steel is suitable for hot working at high temperature (about 750 ℃), the contents of harmful elements and inclusions in the components are high, and the mechanical properties are limited.

Therefore, there is a need to develop a high strength pure carbon steel with high carbon content, micro-alloying, low content of harmful elements and inclusions, strong mechanical properties of the product, and relatively low cost, which can be used in hot working at high temperature.

Disclosure of Invention

The invention provides a method for smelting and preparing zirconium-added high-carbon pure steel in a medium-frequency induction furnace.

The invention is realized by the following technical scheme:

the smelting preparation method of the zirconium-added high-carbon pure steel in the medium-frequency induction furnace comprises the following components in percentage by mass: 0.67-0.75% of C, 0.15-0.37% of Si, 0.30-0.80% of Mn, less than or equal to 0.012% of P, less than or equal to 0.006% of S, 0.20-0.50% of Cr, less than or equal to 0.30% of Mo, less than or equal to 0.30% of V, 0.002-0.100% of ZrC, and the balance of Fe and inevitable impurities;

the preparation method comprises the following steps:

smelting in a medium-frequency induction furnace:

adding a slagging agent and smelting raw materials into the medium-frequency induction furnace, and carrying out melting treatment; then heating to the first tapping temperature, and tapping to obtain molten smelting steel;

and (3) refining in an LF (ladle furnace):

sending the smelting molten steel into an LF furnace for refining treatment, sampling and analyzing at the later stage of the refining treatment, adjusting the temperature of the molten steel to a second tapping temperature, and adding a Mn source, a Si source, a V source and a Zr source into the LF furnace to adjust the components of the molten steel to meet the design requirements to obtain refined molten steel;

and (3) continuous casting treatment:

and carrying out continuous casting treatment on the refined molten steel to obtain the zirconium-added high-carbon pure steel.

In a preferred embodiment, in the smelting step of the medium-frequency induction furnace, the smelting raw materials are industrial pure iron, a carburant, a Mn source, a Si source, a Cr source and a Mo source; preferably, the Mn source is electrolytic Mn, the Si source is Si-Fe alloy, the Cr source is a Cr simple substance, and the Mo source is a Mo simple substance; the V source is a V-Fe alloy, and the Zr source is a Zr-Fe alloy.

In a preferred embodiment, in the smelting step of the medium frequency induction furnace, the amount of the carburant is 0.7-0.8% of the mass of the industrial pure iron.

In a preferred embodiment, in the smelting step of the medium-frequency induction furnace, the mass ratio of the slagging agent to the smelting raw materials is (5-10): 1000.

in a preferred embodiment, in the smelting step of the medium-frequency induction furnace, the slagging agent is one or a combination of several of active quicklime, fluorite and expanded perlite.

In a preferred embodiment, in the smelting step of the medium frequency induction furnace, the first tapping temperature is 1620-.

In a preferred embodiment, in the LF furnace refining step, the refining treatment temperature is 1600-; the second tapping temperature is 1620-1660 ℃.

In a preferred embodiment, the preparation method further comprises: in the smelting step of the medium-frequency induction furnace, the slagging agent is paved at the bottom of the medium-frequency induction furnace.

In a preferred embodiment, the zirconium-containing high carbon pure steel consists of the following components: 0.67-0.75% of C, 0.15-0.3% of Si, 0.3-0.6% of Mn, less than or equal to 0.012% of P, less than or equal to 0.006% of S, 0.25-0.40% of Cr, 0.010-0.025% of Mo0.20-0.30% of V, 0.002-0.01% of Zr, and the balance of Fe and inevitable impurities.

In a preferred embodiment, the tensile strength Rm of the zirconium-added high-carbon pure steel is more than or equal to 1400MPa, and the yield strength R0.2 is more than or equal to 1300 MPa.

Compared with the prior art, the invention has the following beneficial effects:

1. on the basis of the high-quality carbon structural steel 70# steel prepared by the method, the content of harmful element S, P, O, N is further reduced, the content of inclusions is reduced, molten steel is purified, and the mechanical properties of the steel can be greatly improved.

2. The mechanical properties of the product prepared by the method are greatly improved compared with 70# steel and high-carbon pure steel 72A, and the performance of steel products obtained by smelting in a medium-frequency induction furnace, refining in an LF furnace, continuous casting treatment, forging, hot rolling, cold rolling and heat treatment is detected, and the results are as follows: the tensile strength Rm is more than or equal to 1400 MPa; the yield strength R0.2 is more than or equal to 1300MPa, the plate is used for sintering the saw blade mother plate, the plastic deformation damage is small, the service life is prolonged, and in addition, the steel has low production cost.

3. The chemical components of the invention are reasonably proportioned, and the product quality is improved together: the addition of Cr effectively improves the toughness of steel; the addition of a small amount of V can effectively control the form and distribution of crystal grains in the steel and improve the mechanical property, strength and plasticity of the steel; addition of Zr can improve hardenability.

4. The ingredients of the invention follow the principle of 'fine material', namely the industrial pure iron, the high-purity carbon increasing agent, the electrolytic Mn, the metal Cr simple substance, the Si-Fe and other metal raw materials are used for feeding into the furnace, thereby reducing the introduction of harmful elements and improving the purity of the steel.

5. The mechanical properties of the high-strength carbon pure steel are further improved by the reasonable proportion of the components and the synergistic effect of the components and the steps and parameters of the preparation method.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are only for the purpose of the present invention and are not intended to limit the scope of the present invention. It should be understood that various changes and modifications can be made by those skilled in the art after reading the disclosure of the present invention, and equivalents fall within the scope of the appended claims.

The invention provides a preparation method of the zirconium-added high-carbon pure steel (namely the high-strength carbon pure steel), which is a production process taking a medium-frequency induction furnace and an LF furnace as main equipment. The key characteristic of the preparation method is the 'concentrate principle', namely, metal raw materials such as industrial pure iron, a high-purity carbon increasing agent, electrolytic Mn, a metal Cr simple substance, Si-Fe and the like are fed into a furnace, so that the introduction of harmful elements is reduced, and the purity of steel is improved. The product is prepared by the process methods of slagging by using active quicklime and fluorite or melting and smelting by using expanded perlite for slag gathering protection, adjusting the temperature and components of an LF furnace, and the like. The preparation method comprises the following steps:

step one, batching:

the industrial pure iron, the carburant (the proportion of C is 0.7-0.8 percent, namely after the carburant is added, the mass percent of C in the carburant accounts for 0.7-0.8 percent of the industrial pure iron), and the electrolytic Mn, Si-Fe alloy, Cr strips and Mo strips are taken as smelting raw materials of the intermediate frequency induction furnace.

In the carburant, the mass percentage of fixed carbon is more than 99%, and the carburant for steel making meeting the YB/T192-2001 industry standard is preferably adopted.

Step two, smelting in a medium-frequency induction furnace:

firstly, paving 5-10Kg/T of iron (namely industrial pure iron) or 5-10Kg/T of slag former of smelting raw materials at the bottom of a medium-frequency induction furnace, adding the prepared smelting raw materials into the medium-frequency induction furnace, and electrifying to carry out melting treatment to melt all materials in the furnace to form a molten pool; the slagging agent is used for slagging to cover molten steel; then heating to the first tapping temperature 1620-.

The slag former is one or a combination of more of active quicklime, fluorite and expanded perlite, and preferably the active quicklime.

Step three, refining in an LF furnace:

and (2) feeding the smelting molten steel into an LF furnace, refining at 1600-.

Step four, continuous casting treatment:

and (3) continuously casting the refined molten steel to obtain the zirconium-added high-carbon pure steel billet.

The preparation method of the invention can also comprise the following steps: forging and rolling the zirconium-added high-carbon pure steel billet, and performing heat treatment to obtain a finished product steel, wherein the forging and rolling process and the heat treatment can adopt a conventional process or a process used in the embodiment of the invention.

The high-strength carbon pure steel prepared by the preparation method disclosed by the invention comprises the following components in percentage by mass: 0.67-0.75% of C, 0.15-0.37% of Si, 0.30-0.80% of Mn, less than or equal to 0.012% of P, less than or equal to 0.006% of S, 0.20-0.50% of Cr, less than or equal to 0.30% of Mo, less than or equal to 0.30% of V, 0.002-0.100% of Zr, and the balance of Fe and inevitable impurities.

Illustratively, the mass percentage of C may be any of 0.67%, 0.68%, 0.70%, 0.72%, 0.75%, or a range between any two; the Si content may be any one of 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, 0.37% or a range between any two of these; the Mn may be contained in an amount of 0.30%, 0.40%, 0.45%, 0.50%, 0.60%, 0.70%, 0.80% by mass or in a range between any two of them; the mass percentage of P may be 0.003%, 0.005%, 0.008%, 0.010%, 0.012%, or a range therebetween; the mass percentage of S may be any of 0.002%, 0.003%, 0.004%, 0.005%, 0.006%, or a range between any two; the Cr may be contained in an amount of 0.20%, 0.25%, 0.30%, 0.35%, 0.40%, 0.45%, 0.50% by mass or in a range between any two of these amounts; the mass percentage of Mo may be any value of 0.05%, 0.08%, 0.1%, 0.2%, 0.25%, 0.3%, or a range between any two; the mass percentage of V may be any value of 0.05%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, or a range between any two; the mass percentage of Zr may be any value or a range between 0.002%, 0.004%, 0.005%, 0.01%, 0.02%, 0.05%, 0.08%, 0.1%.

Wherein, the content of each component is preferably as follows: 0.67-0.75% of C, 0.15-0.3% of Si, 0.3-0.6% of Mn, less than or equal to 0.012% of P, less than or equal to 0.006% of S, 0.25-0.40% of Cr, 0.010-0.025% of Mo, 0.20-0.30% of V and 0.002-0.01% of ZrC.

The chemical component proportions have synergistic effect, the product quality is improved together, and the effects of the components in the steel and the selection reasons of the content of the components are as follows.

C: 0.67 to 0.75%. Carbon is an indispensable element in steel, the gamma phase region of carbon is enlarged in the steel, the carbon is a composition element of high-strength carbide, the strengthening effect of the carbon in the steel is that the components and the structure of the carbide formed by the carbon are closely related, the carbon content in the steel is increased, the yield point and the tensile strength are increased, but the plasticity and the impact property are reduced, so the C content is selected to be 0.67-0.75% by comprehensively considering the performance of the steel.

Si: 0.15 to 0.37%. In the steel-making process, silicon is added as a reducing agent and a deoxidizing agent, and the co-alloying of silicon and molybdenum has an obvious effect of improving the high-temperature oxidation resistance of steel.

Mn: 0.30-0.80%. In the steel-making process, manganese is a good deoxidizer and desulfurizer, and the content of manganese in the invention is selected to be 0.3-0.8%, so that the steel has enough toughness, higher strength and hardness, the quenching property of the steel is improved, and the hot workability of the steel is improved.

Mo is less than or equal to 0.30 percent, molybdenum is refractory metal, the melting point is high (2625 ℃), molybdenum is an alloy element for reducing a gamma-Fe phase region and expanding a α -Fe phase region and is a strong carbide forming element when being dissolved in base metal, molybdenum is an alloying element of steel, the strength, particularly the high-temperature strength and the toughness of the steel can be improved, and the wear resistance, the hardenability, the weldability and the heat resistance of the steel are improved.

0.20 to 0.50 percent of Cr. The addition of Cr can refine the pearlite sheet spacing and improve the hardenability of steel, thereby effectively improving the toughness of steel; the pearlite transformation involves a proportion of chromium entering the cementite and ferrite phases, thereby improving strength properties and altering workability.

V is less than or equal to 0.30 percent. The growth of austenite in steel can be effectively hindered by adding a small amount of vanadium, so that the refinement of crystal grains is realized; vanadium can improve the nucleation driving force of cementite, and cementite crystal grains rapidly and independently nucleate at different positions, so that cementite is distributed in a dispersed manner; the addition of vanadium reduces the thickness of the grain boundary cementite and distributes along the grain boundary dispersedly, and reduces the size of austenite grains, thereby improving the mechanical property of steel; vanadium produces precipitation strengthening in steel, and refines pearlite lamellar spacing in high-carbon steel, and improves the strength and plasticity of the steel.

0.002-0.100% of Zr, and the Zr has refining effect on the annealed structure of the carbon steel to improve hardenability, so that the ferrite grain size is refined. In the case of high carbon steel, it promotes the spheroidization of cementite, and zirconium prevents the growth of austenite grains at high temperature.

Compared with the prior art, the product performance of the invention is as follows:

1. in the prior art, the chemical components of the steel are similar to those of the steel, such as 65#, 70#, 75#, 65Mn, 70Mn and the like, the chemical components are shown in table 1, and the detailed information in table 1 is derived from GB/T699-2015 high-quality carbon structural steel.

Table 1: GB/T699-containing 2015 high-quality carbon structural steel

The mechanical properties of the above structural steels are shown in table 2.

Table 2: mechanical properties of high-quality carbon structural steel (GB/T699-

3. Compared with the steel grades of the above grades, the mechanical property of the product of the invention is obviously enhanced: the tensile strength Rm is more than or equal to 1400MPa, and the yield strength R0.2 is more than or equal to 1300 MPa; the plate is used for sintering a saw blade mother plate, the plastic deformation and damage are small, and the service life of the saw blade mother plate is prolonged.

Example 1

In the present example, a 3T medium frequency induction furnace was used for smelting, and a 3T ladle refining furnace (LF furnace) was used.

The high-strength carbon pure steel of the embodiment comprises the following components in percentage by mass:

C	Mn	Si	P	S	Cr	Mo	V	Zr
									0.68	0.65	0.24	0.011	0.006	0.28	0.021	0.08	0.0075

the balance being Fe and unavoidable impurities.

The preparation method of this example includes the following steps:

(1) preparing materials:

the industrial pure iron, carburant (C proportion is 0.7-0.8%), electrolytic Mn, Si-Fe alloy, Cr bar and Mo bar are used as smelting raw materials of the medium frequency induction furnace.

(2) Smelting in a medium-frequency induction furnace:

laying 8Kg/T iron or active quicklime of smelting raw materials at the bottom of a medium-frequency induction furnace, adding the smelting raw materials into the medium-frequency induction furnace, and electrifying to melt; and raising the temperature to 1630 ℃ of the first tapping temperature, deslagging, and tapping to obtain molten steel.

(3) Refining in an LF furnace:

feeding the smelting molten steel into an LF furnace, refining at 1620 ℃ for 45min, sampling and analyzing at the later stage of refining, and adjusting the temperature of the molten steel to a second tapping temperature of 1630 ℃; and adding electrolytic Mn, SiFe alloy, VFe alloy and ZrFe alloy into the LF furnace to adjust the components to meet the design requirements of steel components, thereby obtaining the refined molten steel with the adjusted components.

(4) Continuous casting treatment: and (3) carrying out continuous casting treatment on the refined molten steel to obtain a continuous casting billet, wherein the loading amount is 3.15T, and 4 round ingots are cast.

(5) Forging treatment: and forging the continuous casting billet into a blank with the thickness of 90mm and the width of 305mm at the forging temperature of 900-1150 ℃, and cooling the blank to the normal temperature in the air.

(6) Rolling treatment:

rolling the forging blank, wherein the hot rolling temperature (initial temperature) is 1150 ℃, rolling the forging blank into strip steel with the thickness of 4.0mm and the width of 305mm, and keeping the temperature of heat-preservation cotton to normal temperature; then cold rolling the steel strip into a strip steel with the thickness of 1.5mm and the width of 305 mm; isothermal oil quenching at 830 ℃; and obtaining the finished product of the zirconium-added high-carbon pure steel.

The mechanical properties of the strip steel obtained by the embodiment are obviously enhanced: the tensile strength Rm is 1468MPa, the yield strength R0.2 is 1345MPa, and the elongation is 9.2%.

Comparative example 1

The high-strength carbon pure steel of the comparative example (i.e. steel) consists of the following components in percentage by mass:

C	Mn	Si	P	S	Cr	Mo	V	Zr
									0.68	0.65	0.24	0.011	0.006	0.28	0.021	0.08	0

the balance being Fe and unavoidable impurities.

The process parameters of the preparation process were the same as those of example 1 except that no Zr-Fe alloy was added in step (3).

The mechanical properties of the strip steel obtained in the embodiment are as follows: the tensile strength Rm was 1170MPa, the yield strength R0.2 was 1100MPa, and the elongation was 5.5%, from which it was seen that the mechanical properties of the pure steel to which Zr element was not added were degraded.

Comparative example 2

The high-strength pure carbon steel of the comparative example comprises the following components in percentage by mass:

C	Mn	Si	P	S	Cr	Mo	V	Zr
									0.68	0.65	0.24	0.011	0.006	0.28	0.021	0.08	0.3

the balance being Fe and unavoidable impurities.

The procedure parameters of the preparation method were the same as those of example 1 except that (3) the amount of Zr-Fe alloy was increased.

The mechanical properties of the strip steel obtained in the embodiment are as follows: the tensile strength Rm is 1450MPa, the yield strength R0.2 is 1370MPa, and the elongation is 1.5%. Brittle fracture of the sample appears, and therefore, the control of the dosage range of the Zr element in the preparation of the pure steel is critical, and if the Zr content is too high, the mechanical property of the product is reduced.

Example 2

C	Mn	Si	P	S	Cr	Mo	V	Zr
									0.75	0.80	0.37	0.012	0.006	0.50	0.3	0.3	0.1

the balance being Fe and unavoidable impurities.

The preparation method of this example includes the following steps:

(1) preparing materials:

(2) Smelting in a medium-frequency induction furnace:

firstly paving 5Kg/T of active quicklime at the bottom of a medium-frequency induction furnace, then adding the smelting raw materials into the medium-frequency induction furnace, and electrifying to melt; and raising the temperature to the first tapping temperature of 1620 ℃, and deslagging, and tapping to obtain molten smelting steel.

(3) Refining in an LF furnace:

feeding the smelting molten steel into an LF furnace, refining at 1600 ℃ for 40min, sampling and analyzing at the later stage of refining, and adjusting the temperature of the molten steel to a second tapping temperature 1620 ℃; and adding electrolytic Mn, SiFe alloy, VFe alloy and ZrFe alloy into the LF furnace to adjust the components to meet the design requirements of steel components, thereby obtaining the refined molten steel with the adjusted components.

(6) Rolling treatment:

The mechanical properties of the strip steel obtained by the embodiment are obviously enhanced: tensile strength Rm is 1400MPa, yield strength R0.2 is 1320MPa, and elongation is 9.0%.

Example 3

C	Mn	Si	P	S	Cr	Mo	V	Zr
									0.67	0.3	0.15	0.012	0.006	0.20	0.1	0.1	0.002

the balance being Fe and unavoidable impurities.

The preparation method of this example includes the following steps:

(1) preparing materials:

(2) Smelting in a medium-frequency induction furnace:

firstly, paving 10Kg/T of active quicklime at the bottom of a medium-frequency induction furnace, then adding the smelting raw materials into the medium-frequency induction furnace, and electrifying to melt; and raising the temperature to the first tapping temperature of 1640 ℃, deslagging, and tapping to obtain molten smelting steel.

(3) Refining in an LF furnace:

feeding the smelting molten steel into an LF furnace, refining at 1640 ℃ for 50min, sampling and analyzing at the later stage of refining, and adjusting the temperature of the molten steel to a second tapping temperature of 1660 ℃; and adding electrolytic Mn, SiFe alloy, VFe alloy and ZrFe alloy into the LF furnace to adjust the components to meet the design requirements of steel components, thereby obtaining the refined molten steel with the adjusted components.

(6) Rolling treatment:

The mechanical properties of the strip steel obtained by the embodiment are obviously enhanced: the tensile strength Rm is 1430MPa, the yield strength R0.2 is 1340MPa, and the elongation is 8.1%.

Example 4

C	Mn	Si	P	S	Cr	Mo	V	Zr
									0.72	0.45	0.18	0.012	0.006	0.45	0.2	0.3	0.01

the balance being Fe and unavoidable impurities.

The preparation method of this example includes the following steps:

(1) preparing materials:

(2) Smelting in a medium-frequency induction furnace:

firstly, 6Kg/T of iron active quicklime is paved at the bottom of a medium-frequency induction furnace, then the smelting raw materials are added into the medium-frequency induction furnace, and the raw materials are electrified and melted; and raising the temperature to 1625 ℃ of the first tapping temperature, deslagging, and tapping to obtain molten smelting steel.

(3) Refining in an LF furnace:

sending the smelting molten steel into an LF furnace to carry out refining treatment for 45min at 1635 ℃, sampling and analyzing at the later stage of the refining treatment, and adjusting the temperature of the molten steel to 1650 ℃ of second tapping; and adding electrolytic Mn, SiFe alloy, VFe alloy and ZrFe alloy into the LF furnace to adjust the components to meet the design requirements of steel components, thereby obtaining the refined molten steel with the adjusted components.

(6) Rolling treatment:

The mechanical properties of the strip steel obtained by the embodiment are obviously enhanced: the tensile strength Rm is 1470MPa, the yield strength R0.2 is 1330MPa, and the elongation is 8.5 percent.

Example 5

C	Mn	Si	P	S	Cr	Mo	V	Zr
									0.70	0.75	0.30	0.012	0.006	0.25	0.3	0.25	0.05

the balance being Fe and unavoidable impurities.

The preparation method of this example includes the following steps:

(1) preparing materials:

(2) Smelting in a medium-frequency induction furnace:

firstly paving 9Kg/T of active quicklime at the bottom of a medium-frequency induction furnace, then adding the smelting raw materials into the medium-frequency induction furnace, and electrifying to melt; and raising the temperature to 1635 ℃ of the first tapping temperature, deslagging, and tapping to obtain molten steel.

(3) Refining in an LF furnace:

sending the smelting molten steel into an LF furnace, refining at 1635 ℃ for 48min, sampling and analyzing at the later stage of refining, and adjusting the temperature of the molten steel to a second tapping temperature of 1655 ℃; and adding electrolytic Mn, SiFe alloy, VFe alloy and ZrFe alloy into the LF furnace to adjust the components to meet the design requirements of steel components, thereby obtaining the refined molten steel with the adjusted components.

(6) Rolling treatment:

The mechanical properties of the strip steel obtained by the embodiment are obviously enhanced: the tensile strength Rm is 1410MPa, the yield strength R0.2 is 1325MPa, and the elongation is 8.5%.

Example 6

C	Mn	Si	P	S	Cr	Mo	V	Zr
									0.72	0.50	0.28	0.012	0.006	0.3	0.15	0.2	0.03

the balance being Fe and unavoidable impurities.

The preparation method of this example includes the following steps:

(1) preparing materials:

(2) Smelting in a medium-frequency induction furnace:

laying 7Kg/T of active quicklime at the bottom of a medium-frequency induction furnace, adding the smelting raw materials into the medium-frequency induction furnace, and powering to melt; and raising the temperature to 1625 ℃ of the first tapping temperature, deslagging, and tapping to obtain molten smelting steel.

(3) Refining in an LF furnace:

feeding the smelting molten steel into an LF furnace, refining at 1610 ℃ for 42min, sampling and analyzing at the later stage of refining, and adjusting the temperature of the molten steel to a second tapping temperature 1640 ℃; and adding electrolytic Mn, SiFe alloy, VFe alloy and ZrFe alloy into the LF furnace to adjust the components to meet the design requirements of steel components, thereby obtaining the refined molten steel with the adjusted components.

(6) Rolling treatment:

The mechanical properties of the strip steel obtained by the embodiment are obviously enhanced: the tensile strength Rm is 1450MPa, the yield strength R0.2 is 1342MPa, and the elongation is 7.8 percent.

Claims

1. A method for smelting and preparing zirconium-added high-carbon pure steel for a sintered saw blade mother plate in a medium-frequency induction furnace is characterized by comprising the following steps of: the zirconium-added high-carbon pure steel comprises the following components in percentage by mass: 0.67-0.75% of C, 0.15-0.37% of Si, 0.30-0.80% of Mn0.012% or less of P, 0.006% or less of S, 0.20-0.45% of Cr, 0.01-0.30% of Mo, 0.05-0.30% of V, 0.002-0.08% of Zr, and the balance of Fe and inevitable impurities;

the preparation method comprises the following steps:

smelting in a medium-frequency induction furnace:

adding a slagging agent and smelting raw materials into the medium-frequency induction furnace, and carrying out melting treatment; then heating to the first tapping temperature, and tapping to obtain molten smelting steel; the smelting raw materials comprise industrial pure iron, a recarburizer, a Mn source, a Si source, a Cr source and a Mo source, wherein the Mn source is electrolytic Mn, the Si source is Si-Fe alloy, the Cr source is a Cr simple substance, the Mo source is a Mo simple substance, the V source is V-Fe alloy, and the Zr source is Zr-Fe alloy; in the recarburizing agent, the mass percent of fixed carbon is more than 99%; in the smelting step of the medium-frequency induction furnace, the first tapping temperature is 1620-;

and (3) refining in an LF (ladle furnace):

sending the smelting molten steel into an LF furnace for refining treatment, sampling and analyzing at the later stage of the refining treatment, adjusting the temperature of the molten steel to a second tapping temperature, and adding a Mn source, a Si source, a V source and a Zr source into the LF furnace to adjust the components of the molten steel to meet the design requirements to obtain refined molten steel; in the LF furnace refining step, the refining treatment temperature is 1600-; the second tapping temperature is 1620-1660 ℃;

and (3) continuous casting treatment:

2. The method of claim 1, wherein:

in the smelting step of the medium-frequency induction furnace, the dosage of the carburant is 0.7-0.8% of the mass of the industrial pure iron.

3. The method of claim 1, wherein:

in the smelting step of the medium-frequency induction furnace, the mass ratio of the slagging medium to the smelting raw materials is (5-10): 1000.

4. the method according to claim 3, wherein:

in the smelting step of the medium-frequency induction furnace, the slagging agent is one or a combination of more of active quicklime, fluorite and expanded perlite.

5. The method of claim 1, wherein:

in the LF refining step, the time is 40-50 min.

6. The production method according to any one of claims 1 to 5, characterized in that: the preparation method further comprises the following steps: in the smelting step of the medium-frequency induction furnace, the slagging agent is paved at the bottom of the medium-frequency induction furnace.

7. The production method according to any one of claims 1 to 5, characterized in that: the zirconium-added high-carbon pure steel comprises the following components: 0.67-0.75% of C, 0.15-0.3% of Si, 0.3-0.6% of Mn, less than or equal to 0.012% of P, less than or equal to 0.006% of S, 0.25-0.40% of Cr0.010-0.025% of Mo, 0.20-0.30% of V, 0.002-0.01% of ZrC, and the balance of Fe and inevitable impurities.