CN114686760A - Steel for 7Ni and production method thereof - Google Patents

Steel for 7Ni and production method thereof Download PDF

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CN114686760A
CN114686760A CN202210297097.1A CN202210297097A CN114686760A CN 114686760 A CN114686760 A CN 114686760A CN 202210297097 A CN202210297097 A CN 202210297097A CN 114686760 A CN114686760 A CN 114686760A
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less
steel
residual
percent
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翟冬雨
刘心阳
杨柳
陈萌
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Nanjing Iron and Steel Co Ltd
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Nanjing Iron and Steel Co Ltd
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Priority to CN202210297097.1A priority Critical patent/CN114686760A/en
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Priority to PCT/CN2022/132289 priority patent/WO2023179058A1/en
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/0006—Adding metallic additives
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/10—Handling in a vacuum
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/001—Heat treatment of ferrous alloys containing Ni
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    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
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    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/008—Heat treatment of ferrous alloys containing Si
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/04—Making ferrous alloys by melting
    • C22C33/06—Making ferrous alloys by melting using master alloys
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    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
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    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
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    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
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    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
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    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Abstract

The invention discloses a steel for 7Ni and a production method thereof, relating to the technical field of steel production, wherein the steel comprises the following chemical components in percentage by mass: c: 0.030 to 0.060%, Si: 0.05-0.30%, Mn: 0.70-1.0%, P is less than or equal to 0.005%, S is less than or equal to 0.002%, residual Nb is less than or equal to 0.0050%, residual V is less than or equal to 0.003%, residual Ti is less than or equal to 0.005%, and Ni: 6.50-7.50%, Cr is less than or equal to 0.05%, Mo: 0.20-0.30%, Cu is less than or equal to 0.05%, Al: 0.020% -0.050%, Mg: 0.0008 to 0.0020 percent, less than or equal to 0.0060 percent of N, less than or equal to 0.0002 percent of H, and the balance of Fe and inevitable impurities. Through a series of process improvements such as smelting, rolling, heat treatment and the like, the process problem of intergranular cracks of the steel grades is solved, the advantages of batch smelting and manufacturing of the steel grades are obtained, the manufacturing stability is greatly improved, and the manufacturing cost is greatly reduced.

Description

Steel for 7Ni and production method thereof
Technical Field
The invention relates to the technical field of steel production, in particular to 7Ni steel and a production method thereof.
Background
With the continuous development of ferrous metallurgy technology in China, the brand competitive advantage of steel enterprises is more and more obvious. In order to improve competitiveness, enterprises continuously develop steel varieties, the nickel-based steel has high alloy content and excellent product quality, but the current situations of high cost and waste in low-end market application exist, wherein the 7Ni steel is the steel for containers with 7% of nickel content, and how to reduce the manufacturing cost of the 7Ni steel is a key step for the enterprises to obtain good market competitive advantages.
Disclosure of Invention
Aiming at the technical problems, the invention overcomes the defects of the prior art and provides the steel for 7Ni, which comprises the following chemical components in percentage by mass: c: 0.030 to 0.060%, Si: 0.05-0.30%, Mn: 0.70-1.0%, P is less than or equal to 0.005%, S is less than or equal to 0.002%, residual Nb is less than or equal to 0.0050%, residual V is less than or equal to 0.003%, residual Ti is less than or equal to 0.005%, and Ni: 6.50-7.50%, Cr is less than or equal to 0.05%, Mo: 0.20-0.30%, Cu is less than or equal to 0.05%, Al: 0.020% -0.050%, Mg: 0.0008 to 0.0020 percent, less than or equal to 0.0060 percent of N, less than or equal to 0.0002 percent of H, and the balance of Fe and inevitable impurities.
The technical scheme of the invention is further defined as follows:
the steel for 7Ni comprises the following chemical components in percentage by mass: c: 0.030-0.050%, Si: 0.05-0.20%, Mn: 0.70-0.9%, P is less than or equal to 0.005%, S is less than or equal to 0.002%, residual Nb is less than or equal to 0.0050%, residual V is less than or equal to 0.003%, residual Ti is less than or equal to 0.005%, and Ni: 6.50-7.30%, Cr is less than or equal to 0.05%, Mo: 0.20-0.25%, Cu is less than or equal to 0.050%, Al: 0.020-0.040%, Mg: 0.0008 to 0.0018 percent, less than or equal to 0.0050 percent of N, less than or equal to 0.0002 percent of H, and the balance of Fe and inevitable impurities.
The steel for 7Ni comprises the following chemical components in percentage by mass: c: 0.035% -0.055%, Si: 0.15-0.25%, Mn: 0.80-0.90%, P is less than or equal to 0.005%, S is less than or equal to 0.002%, residual Nb is less than or equal to 0.0050%, residual V is less than or equal to 0.003%, residual Ti is less than or equal to 0.005%, and Ni: 6.80-7.20%, Cr is less than or equal to 0.05%, Mo: 0.22-0.28%, Cu is less than or equal to 0.050%, Al: 0.025% -0.045%, Mg: 0.0010 to 0.0018 percent, less than or equal to 0.0060 percent of N, less than or equal to 0.0002 percent of H, and the balance of Fe and inevitable impurities.
The steel for 7Ni comprises the following chemical components in percentage by mass: c: 0.040% -0.060%, Si: 0.20-0.30%, Mn: 0.80-1.0%, P is less than or equal to 0.005%, S is less than or equal to 0.002%, residual Nb is less than or equal to 0.0050%, residual V is less than or equal to 0.003%, residual Ti is less than or equal to 0.005%, and Ni: 6.80-7.50%, Cr is less than or equal to 0.05%, Mo: 0.25-0.30%, Cu is less than or equal to 0.050%, Al: 0.025-0.050%, Mg: 0.0010 to 0.0020 percent, less than or equal to 0.0060 percent of N, less than or equal to 0.0002 percent of H, and the balance of Fe and inevitable impurities.
The invention also aims to provide a production method of the steel for 7Ni, which comprises the following steps:
s1, desulfurizing the molten iron, then sending the molten iron to a converter for smelting, smelting by adopting a top-bottom combined blowing process, adding the nickel-molybdenum alloy into the converter along with the scrap steel, counting the weight of the scrap steel, supplying 80% of oxygen for deslagging, and carrying out tapping operation when the smelting end point temperature is 1580-1620 ℃ and the components meet the requirements;
s2, feeding molten steel to refining for deoxidation alloying and desulfurization, feeding the molten steel to RH for vacuum treatment after the component temperature meets the requirement, keeping the vacuum degree at less than or equal to 3.0mbar for 20-25 minutes, and roasting the molten steel into a 200-220 m magnesium-aluminum wire after the vacuum treatment;
s3, after finishing molten steel refining, sending the casting blank to continuous casting for casting, wherein the casting speed is 0.6-1.3 m/min, the superheat degree is 25-35 ℃, an electromagnetic stirring and dynamic soft reduction process is adopted, after the casting blank is discharged from the continuous casting, a heat preservation pit is cooled for 48 hours in a pile, and then surface inspection is carried out, mechanical grinding is adopted after the surface inspection of the casting blank is qualified, and the ground casting blank is sprayed by high-temperature antioxidant coating;
s4, processing the casting blank, and sending the processed casting blank to a heating furnace for heating, wherein the heating process of the heating furnace is as follows: heating to 600 ℃ at a heating speed of 10-15 ℃/min, heating to 600-1000 ℃ at a heating speed of 5-7 ℃/min, heating to 1000-1100 ℃ at a heating speed of 2 ℃/min, keeping the temperature at 1100 ℃ for 20min, and taking out of the heating furnace;
s5, rolling by adopting a two-stage rolling process, wherein the second-stage rolling temperature is 800-950 ℃, the final rolling temperature is 800-900 ℃, and the re-reddening temperature is 400-600 ℃;
s6, quenching at 760-790 ℃, keeping the temperature for 10-30 minutes, tempering at 550-650 ℃ after quenching for 10-15 minutes, and air cooling;
and S7, checking the surface of the steel plate after heat treatment, marking after the performance detection is qualified, warehousing and delivering.
In the production method of the 7Ni steel, in the step S3, the grinding depth is 1-2 mm, and the spraying thickness is 0.1-0.3 mm.
The invention has the beneficial effects that:
(1) the invention researches the factors influencing the surface quality of the steel by deeply researching the mechanism of the steel, carries out corresponding development and application, solves the process problem of intergranular cracks of the steel by a series of process improvements such as smelting, rolling, heat treatment and the like, obtains the advantages of batch smelting and manufacturing of the steel, greatly improves the manufacturing stability, greatly reduces the manufacturing cost and effectively improves the market competitiveness of the product;
(2) the invention adopts the magnesium metallurgy technology to improve the form of impurities, improve the cleanliness of the product and avoid intergranular cracks caused by the aggregation of impurities on the surface;
(3) according to the invention, the carbon content of the steel is improved by reducing the contents of nitrogen and hydrogen gas and phosphorus and sulfur, the deterioration of manganese sulfide inclusion and gas content on the surface quality of the steel is reduced, and a small amount of niobium is added to play roles in nitrogen fixation and carbon fixation, so that the incidence rate of surface intergranular cracks is reduced;
(4) according to the invention, the unique antioxidant coating is adopted for spraying, so that the secondary oxidation of the casting blank in the heating process is avoided, the generation amount of iron oxide scales on the surface of the casting blank in the rolling process is reduced, and the surface quality of the rolled steel plate is improved;
(5) the phase change temperature of the high nickel steel is 570 ℃, the finishing temperature is 730 ℃, the heating process quality is carried out at different heating rates, the linear expansion and the heat conductivity coefficient are reduced, and intergranular cracks caused by phase change stress in the heating process are avoided;
(6) according to the invention, high-temperature oxidation cracks on the surface of the casting blank can be caused by overhigh heating tapping temperature, and the cracks become more obvious along with the coarseness of austenite, so that high-temperature intergranular cracks on the surface of the casting blank are effectively avoided by low-temperature tapping;
(7) the invention adopts the low-temperature heat treatment process, can effectively avoid the crystal oxidation crack trend in the rolling process, avoid the intergranular cracks in the austenitizing process caused by the widening and effectively reduce the batch crack incidence rate of the quenched and tempered steel plate;
(8) according to the invention, the nickel-molybdenum alloy is added into the converter according to the form of the scrap steel, the calorific value is not influenced, and meanwhile, because of the addition of the nickel-molybdenum alloy, the coagulation and fixation of the molten steel are effectively reduced, the requirement of low-temperature steel tapping is met, the removal of carbon and phosphorus elements is facilitated, and the smelting speed is increased.
Drawings
FIG. 1 is a metallographic structure diagram of example 1.
Detailed Description
Example 1
The steel for 7Ni provided in this embodiment has the following chemical components by mass percent: c: 0.043%, Si: 0.16%, Mn: 0.79%, P: 0.003%, S: 0.0011%, Nb: 0.0030% (residue), V: 0.002% (residual), Ti: 0.002% (residual), Ni: 7.1%, Cr: 0.02%, Mo: 0.23%, Cu: 0.030%, Al: 0.029%, Mg: 0.0017%, N: 0.0036%, H: 0.00017%, the balance being Fe and unavoidable impurities.
The preparation method comprises the following steps:
s1, desulfurizing the molten iron, then sending the molten iron to a converter for smelting, smelting by adopting a top-bottom combined blowing process, adding the nickel-molybdenum alloy into the converter along with the scrap steel, counting the weight of the scrap steel, supplying 80% of oxygen for deslagging, and carrying out tapping operation when the smelting end point temperature is 1602 ℃ and the components meet the requirements;
s2, sending the molten steel to refining for deoxidation alloying and desulfurization, sending the molten steel to RH for vacuum treatment after the component temperature is in accordance with the requirement, wherein the vacuum degree is less than or equal to 3.0mbar, the vacuum retention time is 21 minutes, and roasting the molten steel into a 210-meter magnesium-aluminum wire after the vacuum treatment;
s3, after finishing molten steel refining, sending the casting blank to continuous casting for casting, wherein the casting speed is 0.9m/min, the superheat degree is 27 ℃, an electromagnetic stirring and dynamic soft reduction process is adopted, the casting blank is discharged from the continuous casting, is subjected to surface inspection after being cooled in a heat preservation pit for 48 hours, is mechanically ground after being qualified in surface inspection, the grinding depth is 1.6mm, and the ground casting blank is sprayed with high-temperature antioxidant coating with the spraying thickness of 0.1 mm;
s4, processing the casting blank, and sending the processed casting blank to a heating furnace for heating, wherein the heating process of the heating furnace is as follows: heating to 600 ℃ at a heating speed of 13 ℃/min, heating to 600-1000 ℃ at a heating speed of 6 ℃/min, heating to 1000-1100 ℃ at a heating speed of 2 ℃/min, preserving heat at 1100 ℃ for 20min, and taking out of the heating furnace;
s5, rolling by adopting a two-stage rolling process, wherein the second-stage rolling temperature is 880 ℃, the final rolling temperature is 850 ℃, and the re-reddening temperature is 460 ℃;
s6, quenching at 780 ℃, preserving heat for 22 minutes, tempering at 630 ℃ after quenching, preserving heat for 12 minutes, and air cooling;
and S7, performing surface inspection and performance inspection on the steel plate after heat treatment, marking, warehousing and delivering.
Example 2
The steel for 7Ni provided in this embodiment has the following chemical components by mass percent: c: 0.0430%, Si: 0.09%, Mn: 0.779%, P: 0.002%, S: 0.0012%, Nb: 0.0020% (residue), V: 0.002% (residual), Ti: 0.003% (residual), Ni: 6.96%, Cr: 0.02%, Mo: 0.21%, Cu: 0.010%, Al: 0.038%, Mg: 0.0014%, N: 0.0046%, H: 0.00017%, the balance being Fe and unavoidable impurities.
The preparation method comprises the following steps:
s1, desulfurizing the molten iron, then sending the molten iron to a converter for smelting, smelting by adopting a top-bottom combined blowing process, adding the nickel-molybdenum alloy into the converter along with the scrap steel, counting the weight of the scrap steel, supplying 80% of oxygen for deslagging, and carrying out tapping operation when the smelting end point temperature is 1586 ℃ and the components meet the requirements;
s2, feeding molten steel to refining for deoxidation alloying and desulfurization, feeding the molten steel to RH for vacuum treatment after the component temperature meets the requirement, keeping the vacuum degree less than or equal to 3.0mbar for 23 minutes, and roasting the molten steel into a 220-meter magnesium-aluminum wire after the vacuum treatment;
s3, after finishing molten steel refining, sending the casting blank to continuous casting for casting, wherein the casting speed is 0.7m/min, the superheat degree is 26 ℃, an electromagnetic stirring and dynamic soft reduction process is adopted, the casting blank is discharged from the continuous casting, a heat preservation pit is cooled in a pile for 48 hours, then surface inspection is carried out, mechanical grinding is adopted after the casting blank surface inspection is qualified, the grinding depth is 1.9mm, the ground casting blank is sprayed by high-temperature antioxidant coating, and the spraying thickness is 0.13 mm;
s4, processing the casting blank, and sending the processed casting blank to a heating furnace for heating, wherein the heating process of the heating furnace is as follows: heating to 600 ℃ at a heating speed of 14 ℃/min, heating to 600-1000 ℃ at a heating speed of 5.7 ℃/min, heating to 1000-1100 ℃ at a heating speed of 2 ℃/min, keeping the temperature of 1100 ℃ for 20min, and taking out of the heating furnace;
s5, rolling by adopting a two-stage rolling process, wherein the second-stage rolling temperature is 910 ℃, the final rolling temperature is 890 ℃, and the re-reddening temperature is 580 ℃;
s6, quenching at 780 ℃, preserving heat for 16 minutes, tempering at 590 ℃ after quenching for 13 minutes, and air cooling;
and S7, checking the surface of the steel plate after heat treatment, marking after the performance detection is qualified, warehousing and delivering.
Example 3
The steel for 7Ni provided in this embodiment has the following chemical components by mass percent: c: 0.056%, Si: 0.260%, Mn: 0.93%, P: 0.002%, S: 0.0013%, Nb: 0.003% (residual), V: 0.002% (residual), Ti: 0.002% (residual), Ni: 7.3%, Cr: : 0.02%, Mo: 0.29%, Cu: 0.020%, Al: 0.041%, Mg: 0.0016%, N: 0.0036%, H: 0.00011%, the balance being Fe and unavoidable impurities.
The preparation method comprises the following steps:
s1, desulfurizing the molten iron, then sending the molten iron to a converter for smelting, smelting by adopting a top-bottom combined blowing process, adding the nickel-molybdenum alloy into the converter along with the scrap steel, counting the weight of the scrap steel, supplying 80% of oxygen for deslagging, and carrying out tapping operation when the smelting end point temperature is 1606 ℃ and the components meet the requirements;
s2, sending the molten steel to refining for deoxidation alloying and desulfurization, sending the molten steel to RH for vacuum treatment after the component temperature meets the requirement, keeping the vacuum degree less than or equal to 3.0mbar for 24 minutes, and roasting the molten steel into a 210-meter magnesium-aluminum wire after the vacuum treatment;
s3, after finishing molten steel refining, sending the casting blank to continuous casting for casting, wherein the casting speed is 0.7m/min, the superheat degree is 27 ℃, an electromagnetic stirring and dynamic soft reduction process is adopted, the casting blank is discharged from the continuous casting, a heat preservation pit is cooled in a pile for 48 hours, then surface inspection is carried out, mechanical grinding is adopted after the casting blank surface inspection is qualified, the grinding depth is 1.2mm, the ground casting blank is sprayed by high-temperature antioxidant coating, and the spraying thickness is 0.2 mm;
s4, processing the casting blank, and sending the processed casting blank to a heating furnace for heating, wherein the heating process of the heating furnace is as follows: heating to 600 ℃ at a heating speed of 13 ℃/min, heating to 600-1000 ℃ at a heating speed of 6 ℃/min, heating to 1000-1100 ℃ at a heating speed of 2 ℃/min, keeping the temperature at 1100 ℃ for 20min, and taking out of the heating furnace;
s5, rolling by adopting a two-stage rolling process, wherein the second-stage rolling temperature is 860 ℃, the final rolling temperature is 830 ℃, and the re-reddening temperature is 420 ℃;
s6, quenching at 766 ℃ for 28 minutes, tempering at 590 ℃ for 12 minutes after quenching, and air cooling;
and S7, performing surface inspection and performance inspection on the steel plate after heat treatment, marking, warehousing and delivering.
The mechanical properties of examples 1-3 are given in the following table:
Figure 643841DEST_PATH_IMAGE002
the method has the advantages of simple operation, stable execution of the production process, obvious effect, suitability for other nickel series varieties with 5.5-9.5% of nickel, and obvious economic benefit and safety benefit.
In addition to the above embodiments, the present invention may have other embodiments. All technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the protection scope of the claims of the present invention.

Claims (6)

1. A steel for 7Ni, characterized in that: the chemical components and the mass percentage are as follows: c: 0.030 to 0.060%, Si: 0.05-0.30%, Mn: 0.70-1.0%, P is less than or equal to 0.005%, S is less than or equal to 0.002%, residual Nb is less than or equal to 0.0050%, residual V is less than or equal to 0.003%, residual Ti is less than or equal to 0.005%, and Ni: 6.50-7.50%, Cr is less than or equal to 0.05%, Mo: 0.20-0.30%, Cu is less than or equal to 0.05%, Al: 0.020% -0.050%, Mg: 0.0008 to 0.0020 percent, less than or equal to 0.0060 percent of N, less than or equal to 0.0002 percent of H, and the balance of Fe and inevitable impurities.
2. The steel for 7Ni according to claim 1, wherein: the chemical components and the mass percentage are as follows: c: 0.030-0.050%, Si: 0.05-0.20%, Mn: 0.70-0.9%, P is less than or equal to 0.005%, S is less than or equal to 0.002%, residual Nb is less than or equal to 0.0050%, residual V is less than or equal to 0.003%, residual Ti is less than or equal to 0.005%, and Ni: 6.50-7.30%, Cr is less than or equal to 0.05%, Mo: 0.20-0.25%, Cu is less than or equal to 0.050%, Al: 0.020-0.040%, Mg: 0.0008 to 0.0018 percent, less than or equal to 0.0050 percent of N, less than or equal to 0.0002 percent of H, and the balance of Fe and inevitable impurities.
3. The steel for 7Ni according to claim 1, wherein: the chemical components and the mass percentage are as follows: c: 0.035-0.055%, Si: 0.15-0.25%, Mn: 0.80-0.90%, P is less than or equal to 0.005%, S is less than or equal to 0.002%, residual Nb is less than or equal to 0.0050%, residual V is less than or equal to 0.003%, residual Ti is less than or equal to 0.005%, and Ni: 6.80-7.20%, Cr is less than or equal to 0.05%, Mo: 0.22-0.28%, Cu is less than or equal to 0.050%, Al: 0.025% -0.045%, Mg: 0.0010 to 0.0018 percent, less than or equal to 0.0060 percent of N, less than or equal to 0.0002 percent of H, and the balance of Fe and inevitable impurities.
4. The steel for 7Ni according to claim 1, wherein: the chemical components and the mass percentage are as follows: c: 0.040% -0.060%, Si: 0.20-0.30%, Mn: 0.80-1.0%, P is less than or equal to 0.005%, S is less than or equal to 0.002%, residual Nb is less than or equal to 0.0050%, residual V is less than or equal to 0.003%, residual Ti is less than or equal to 0.005%, and Ni: 6.80-7.50%, Cr is less than or equal to 0.05%, Mo: 0.25-0.30%, Cu is less than or equal to 0.050%, Al: 0.025-0.050%, Mg: 0.0010 to 0.0020 percent, less than or equal to 0.0060 percent of N, less than or equal to 0.0002 percent of H, and the balance of Fe and inevitable impurities.
5. A production method of steel for 7Ni is characterized by comprising the following steps: application to any of claims 1-4, comprising the steps of:
s1, desulfurizing the molten iron, then sending the molten iron to a converter for smelting, smelting by adopting a top-bottom combined blowing process, adding the nickel-molybdenum alloy into the converter along with the scrap steel, counting the weight of the scrap steel, supplying 80% of oxygen for deslagging, and carrying out tapping operation when the smelting end point temperature is 1580-1620 ℃ and the components meet the requirements;
s2, feeding molten steel to refining for deoxidation alloying and desulfurization, feeding the molten steel to RH for vacuum treatment after the component temperature meets the requirement, keeping the vacuum degree at less than or equal to 3.0mbar for 20-25 minutes, and roasting the molten steel into a 200-220 m magnesium-aluminum wire after the vacuum treatment;
s3, after finishing molten steel refining, sending the casting blank to continuous casting for casting, wherein the casting speed is 0.6-1.3 m/min, the superheat degree is 25-35 ℃, an electromagnetic stirring and dynamic soft reduction process is adopted, after the casting blank is discharged from the continuous casting, a heat preservation pit is cooled for 48 hours in a pile, and then surface inspection is carried out, mechanical grinding is adopted after the surface inspection of the casting blank is qualified, and the ground casting blank is sprayed by high-temperature antioxidant coating;
s4, processing the casting blank, sending the processed casting blank to a heating furnace for heating, wherein the heating process of the heating furnace is as follows: heating to 600 ℃ at a heating speed of 10-15 ℃/min, heating to 600-1000 ℃ at a heating speed of 5-7 ℃/min, heating to 1000-1100 ℃ at a heating speed of 2 ℃/min, keeping the temperature at 1100 ℃ for 20min, and taking out of the heating furnace;
s5, rolling by adopting a two-stage rolling process, wherein the second-stage rolling temperature is 800-950 ℃, the final rolling temperature is 800-900 ℃, and the re-reddening temperature is 400-600 ℃;
s6, quenching at 760-790 ℃, keeping the temperature for 10-30 minutes, tempering at 550-650 ℃ after quenching for 10-15 minutes, and air cooling;
and S7, performing surface inspection and performance inspection on the steel plate after heat treatment, marking, warehousing and delivering.
6. The production method of the steel for 7Ni according to claim 5, wherein: in the step S3, the grinding depth is 1-2 mm, and the spraying thickness is 0.1-0.3 mm.
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