CN116121642A - Steel with tensile strength of 1000MPa and preparation method and application thereof - Google Patents

Steel with tensile strength of 1000MPa and preparation method and application thereof Download PDF

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CN116121642A
CN116121642A CN202211659025.3A CN202211659025A CN116121642A CN 116121642 A CN116121642 A CN 116121642A CN 202211659025 A CN202211659025 A CN 202211659025A CN 116121642 A CN116121642 A CN 116121642A
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steel
percent
tensile strength
less
1000mpa
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CN116121642B (en
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吴刚
刘志璞
文小明
韩宇
张迎征
陈红远
宫震
王全洲
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Bengang Steel Plates Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • 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
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/30—Regulating or controlling the blowing
    • C21C5/35—Blowing from above and through the bath
    • 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
    • C21C7/0075—Treating in a ladle furnace, e.g. up-/reheating of molten steel within the ladle
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/06—Deoxidising, e.g. killing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/064—Dephosphorising; Desulfurising
    • C21C7/0645—Agents used for dephosphorising or desulfurising
    • 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
    • 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
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/20—Ferrous alloys, e.g. steel alloys containing chromium with copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • 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
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Abstract

The invention discloses 20MnCrS5 steel, and belongs to the technical field of preparation of large-specification gear steel. The invention comprises the following chemical elements in percentage by weight: c:0.17 to 0.22 percent, si:0.15 to 0.40 percent of Mn:1.10 to 1.30 percent, P is less than or equal to 0.035 percent, S:0.035 to 0.045%, cr:1.00% -1.30%, alt:0.020% -0.060% and the balance of iron and unavoidable impurities. The invention can improve the cooling condition of the steel ingot by adopting the die casting process, so that the temperature gradient and the cooling strength are weaker than those of the continuous casting process when the ingot is solidified, the dendritic crystal lap joint of the solidification structure is avoided, the element segregation is lightened, and the compactness of the steel is improved.

Description

Steel with tensile strength of 1000MPa and preparation method and application thereof
Technical Field
The invention belongs to the technical field of ferrous metallurgy, and particularly relates to steel with 1000 MPa-level tensile strength, and a preparation method and application thereof.
Background
With the rapid development of the automobile industry, the dead weight of the automobile is in direct proportion to the oil consumption of the automobile, namely, the larger the dead weight of the automobile is, the larger the oil consumption of the automobile is, and the reduction of the dead weight of the automobile is one of the most effective measures for realizing energy conservation, consumption reduction and environmental protection.
The transmission shaft of automobile is an important part of transmission power in transmission system, and together with drive axle and speed changing box, it can transfer the power of engine to wheels so as to make automobile run at high speed. The steel plate is required to bear the effects of various alternating stresses such as compression, impact, torsion, shearing and the like, and also bear the impacts of braking, starting and complex road conditions, and the steel plate is required to have high strength, high toughness and good fracture toughness. The transmission shaft tube has the characteristics of high geometric dimension precision and uniform mass distribution.
The steel pipes are divided into two types, namely a seamless steel pipe and a welded steel pipe, and the seamless steel pipe has the defects of low yield, large additional deformation and low wall thickness precision and is not suitable for manufacturing a transmission shaft. Welded steel pipes are generally divided into two types, namely straight welded pipes and spiral welded pipes, and the existing welded steel pipes have the defects of low strength, thicker steel plates and great self weight.
Disclosure of Invention
In order to solve the problems, the steel plate for the automobile transmission shaft pipe with the tensile strength of more than or equal to 1000MPa is adopted, so that the thickness of the steel plate is reduced from 6.0mm to 12.0mm to 2.0 to 5.5mm, and the purposes of saving energy, reducing consumption and reducing the dead weight of an automobile are achieved.
The first aspect of the invention provides steel with tensile strength not less than 1000MPa, which comprises the following components in percentage by weight: c:0.20-0.40%; si:0.70-1.0%; mn:2.50-3.0%; p is less than or equal to 0.010 percent; s is less than or equal to 0.005%; mo:0.50 to 0.80 percent; cr:1.50 to 2.0 percent; 0.50 to 0.80 percent of Cu; v:0.10 to 0.20 percent; the balance being iron and unavoidable impurities.
Further, the thickness of the steel with the tensile strength of more than or equal to 1000MPa grade is 2.0 mm-12.0 mm, and the yield strength is 755-890 MPa; the impact energy KV2 at 20 ℃ is 80-160J; a is that 50 12-20%; the relative corrosion rate is 30-42%.
The second aspect of the invention provides a method for preparing steel with tensile strength not less than 1000MPa, comprising the following steps:
and (3) molten iron pretreatment: adding a desulfurizing agent to ensure that the sulfur content in the molten iron is less than or equal to 0.003 percent, and adding the molten iron into a converter;
smelting in a converter: the molten iron and the scrap steel which are added into the converter are blown into the converter by bottom blowing inert gas, lime and light burned dolomite are adopted for slag making, the oxygen blowing time is 12-16 minutes, when the weight ratio of C in the end point component is 0.18-0.25%, steel is tapped when the temperature reaches 1660-1700 ℃, and alloying treatment is carried out in the tapping process, so that Cr, mo, cu and V in the steel reach the lower limit requirement;
LF refining: transferring molten steel smelted by the converter into an LF refining furnace, and adjusting the following components in the steel by weight percent: 0.50 to 0.80 percent of Cr:1.50 to 2.0 percent of Cu:0.50 to 0.80 percent of V:0.10 to 0.20 percent of deoxidizer is added, argon or nitrogen is blown into the bottom of the casting blank, and the casting blank is formed;
heating: in order to ensure the surface quality and the thickness of the decarburized layer of the steel, the continuous casting billet adopts a hot feeding and hot charging process, wherein the hot feeding and hot charging process means that the temperature of the continuous casting billet is ensured to be more than 450 ℃, or the continuous casting billet is arranged in a furnace within 5 hours, and the heating temperature is 1160-1200 ℃, so that the prior austenite grains reach the level of not more than 5.0;
rough rolling: r1 is rolled for 3-5 times, R2 is rolled for 3-5 times, and when the temperature reaches 960-980 ℃, the finishing mill group is entered;
finish rolling: adopting multi-frame hot continuous rolling, wherein cooling water is input between frames, and the final rolling temperature of the finish rolling is 825-855 ℃;
and (3) coiling: the coiling temperature is 385-415 ℃.
Further, the desulfurizing agent consists of magnesium powder and lime powder, wherein the weight ratio of the magnesium powder to the lime powder is 1:4.0 to 5.0; the slag discharging amount in converter smelting is less than or equal to 5 kg/ton of steel.
Further, the deoxidizer consists of aluminum-manganese-iron, wherein the weight ratio of the aluminum-manganese-iron in the deoxidizer is as follows: mn: fe=40: 30:30; the molten steel top slag in the LF refining furnace is kept between 30mm and 40mm.
Further, the soaking time of the continuous casting blank in the hot feeding and hot charging process is 60-70 min.
Further, the floating temperature waiting time of the rough rolling is 30S-60S.
The third aspect of the invention protects the application of the steel with the tensile strength more than or equal to 1000MPa in the automobile transmission shaft.
Further, the thickness of the automobile transmission shaft is 2.0-12.0 mm, the yield strength is 750-900 MPa, the tensile strength is 1050-1180 MPa, A 50 12-20%.
The beneficial effects are that:
according to the invention, elements such as molybdenum, vanadium, chromium and copper are added into steel, so that the strength and the performance of the steel plate are improved, on one hand, the strength, the toughness and the hardenability of the steel plate are improved by adding manganese, molybdenum and vanadium, and on the other hand, the chromium and copper are added, so that the steel plate has good corrosion resistance, in the smelting process, the alloy elements such as molybdenum, vanadium, chromium, copper and manganese are added, the grain size of original austenite is increased, and in the subsequent heating, rough rolling, finish rolling and laminar cooling processes, the grain size and the structure of the steel are controlled, so that the steel for the automobile transmission shaft tube with the corrosion resistance, the tensile strength of which is more than or equal to 1000MPa, is obtained.
The corrosion-resistant automobile transmission shaft tube produced by the method has the advantages that the corrosion same as common carbon steel is generated in the initial stage, the advantages are not great, holes and cracks exist in the rust layer of the transmission shaft tube, so that corrosive medium is easy to infiltrate, directly contacts with a matrix, and the corrosion is accelerated, so that the corrosion rates of the carbon steel and the transmission shaft tube in the initial stage of corrosion are relatively high, alloy elements Cu, cr, V, mo, mn and the like added in the steel gradually play roles along with the continuous operation of the automobile transmission shaft, the surface conductivity is reduced, the steel matrix is self-precipitated and covered, the growth of the rust layer is hindered, the crystallization of the rust is delayed, the uniform dissolution of the steel is accelerated, and the rapid growth of corrosion products can be hindered. The healing of the defect is accelerated, the channel of the corrosion medium directly contacting the substrate is blocked, the rust layer is densified, the corrosion process of the transmission shaft is controlled by diffusion, the corrosion speed is reduced, and stable inner and outer surface layers are finally formed.
Drawings
FIG. 1 is a metallographic structure of a steel sheet of example 1.
FIG. 2 is a metallographic structure of the steel sheet of example 2.
FIG. 3 is a metallographic structure of the steel sheet of example 3.
FIG. 4 is a metallographic structure of the steel sheet of example 4.
FIG. 5 is a metallographic structure diagram of the inclusion of the steel sheet of example 1.
FIG. 6 is a metallographic structure diagram of a comparative steel sheet.
FIG. 7 is a metallographic structure diagram of inclusions in a comparative steel sheet.
Detailed Description
The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention comprises the following chemical components in percentage by mass: c0.20-0.40%; si0.70-1.0%; mn2.50-3.0%; p is less than or equal to 0.010 percent; s is less than or equal to 0.005%; mo0.50-0.80%; cr1.50-2.0%; 0.50 to 0.80 percent of Cu; v:0.10 to 0.20 percent; the balance being iron and unavoidable impurities.
Wherein: the element with the most economical strength improvement can determine the performance of the steel, is one of effective elements for stabilizing austenite, can improve the hardenability, plays a role in strengthening a gap solid solution in the steel, and improves the strength and the hardness of the steel along with the increase of the content of C, but reduces the toughness, so that the carbon content is controlled to be 0.20-0.40%;
si: the alloy has good deoxidizing capability, si in steel exists in austenite or ferrite in solid solution form, has strong solid solution strengthening and cold working deformation capability, makes C curve move right sufficiently, improves the strength of steel, and certain Si can promote carbon diffusion to reduce the carbon content in austenite, is beneficial to the stability of austenite (supercooling), so that the Si content is 0.7-1.0%.
Mn: the strength of the steel can be improved, the hardenability of the steel is improved, the martensite and bainite transformation temperature of the steel is reduced, the overheat sensitivity of the steel is increased by Mn, and under the condition of slightly overheat, crystal grains are coarsened, so that the Mn content is controlled to be as follows: 2.50 to 3.0 percent;
cr, cu: cr is added into the steel, so that hardenability can be improved on the one hand; on the other hand, the corrosion resistance can be increased, chromium and copper are preferably added, a compact and uniform corrosion layer is formed on the surface of the transmission shaft, and noble nickel is not added, so that the Cr content of the invention is as follows: 1.5 to 2.0 percent, cu content: 0.50 to 0.80 percent.
Mo: the purpose of adding Cr together to steel is to improve hardenability and toughness, and the composite action of Mo and Cr makes supercooled austenite move to the ferrite isothermal transformation curve to the right and makes ferrite transformation start line protrude, so that the Mo content is controlled: 0.50 to 0.80 percent.
V: the steel has precipitation strengthening effect, exists in the form of VC and VN, is beneficial to improving the strength of the steel, and has the optimal addition amount V of 0.10-0.20%.
The method for smelting the steel for the automobile transmission shaft pipe, provided by the invention, comprises the following specific steps:
and (3) molten iron pretreatment: adding desulfurization powder into the molten iron pretreatment device to ensure that the sulfur content in the molten iron is less than or equal to 0.003 percent, and adding into a converter;
smelting in a converter: adding molten iron and scrap steel into a converter, smelting by adopting a top-bottom combined blowing converter, blowing by adopting bottom blowing inert gas in the whole process, and slagging by adopting lime and light burned dolomite, wherein the oxygen blowing time is 12-16 minutes, when the end point components and the temperature reach the tapping requirements, tapping is started, a tapping hole is round, ferromolybdenum, ferrochrome, copper, ferrovanadium and the like are added in the tapping process, and the tapping temperature is controlled between 1660 ℃ and 1700 ℃;
LF refining: pouring molten steel into an LF refining furnace, adjusting the contents of Mo, cr, cu and V in the steel to the range of internal control components according to target components, simultaneously adding a deoxidizer, injecting argon or nitrogen from the bottom, and pouring by a straight arc continuous casting machine after alloying to form a continuous casting blank.
Heating: the continuous casting blank adopts a hot feeding and hot charging process, and the heating temperature is 1180+/-20 ℃ so that the prior austenite grains are sufficiently coarse;
rough rolling: r1 is rolled for 3-5 times, R2 is rolled for 3-5 times, and when the temperature reaches 960-980 ℃, the finishing mill group is entered;
finish rolling: adopting multi-stand hot continuous rolling, adding cooling water between stands, and finishing rolling at 825-855 ℃;
and (3) coiling: the coiling temperature is 385-415 ℃.
The desulfurizing agent consists of magnesium powder and lime powder, and the weight ratio of the magnesium powder to the lime powder is 1:4.0 to 5.0;
in the converter smelting tapping step, the slag discharging amount is less than or equal to 5 kg/ton of steel;
the deoxidizer added in the external refining step adopts deoxidizer composed of aluminum-manganese-iron, and the adding amount of the deoxidizer is 400-500 kg per furnace steel.
In the external refining step, the top slag of the molten steel in the furnace is kept between 30mm and 40mm.
In a heating furnace, soaking time of a continuous casting billet is 60-70 min, heating temperature is 1160-1200 ℃, and the concept of increasing the size of original austenite grains is introduced, so that alloy elements are fully dissolved in the heating process, and the size of the original austenite grains is fully grown;
during rough rolling, the rolling is carried out for 30S-60S;
the thickness of the transmission shaft produced by the invention is 2.0-12.0 mm, and the yield strength is 750-900 MPa, the tensile strength is 1050-1180 MPa, A 50 The fatigue life of the automobile transmission shaft tube is increased by 50 ten thousand times at 12-20%, and the data show that the special steel for the transmission shaft tube has the performance far exceeding that of the existing transmission shaft tube and has a further thinning space, so that the steel for the transmission shaft tube can realize energy saving, consumption reduction and good corrosion resistance when used for automobiles.
The process flow of the transmission shaft tube comprises the following steps:
blanking, forming, HFW welding, hot tension reducing, cooling control and finished product production.
The following are specific examples.
Example 1
Firstly, preprocessing, namely adding a mixed sulfur agent of magnesium powder and lime powder into a hot-metal ladle, wherein the weight percentage of the magnesium powder and the lime powder is 1:4.0, performing routine detection, and when the sulfur content in the molten iron is less than or equal to 0.003%, finishing the pretreatment of the molten iron, and adding the molten iron and the scrap steel into a converter for smelting; adding lime and light burned dolomite into a 180-ton top-bottom combined blown converter for slagging, then blowing oxygen for 12 minutes, tapping after oxygen blowing is completed, keeping the tapping temperature at 1660 ℃, and adding ferromolybdenum, ferrochrome, copper, ferrovanadium and the like in the tapping process to ensure that the molten steel components reach the tapping requirement, wherein the slag quantity requirement is less than or equal to 5 kg/ton of steel; adding molten steel into an LF refining furnace, adjusting the contents of Mo, cr, cu and V in the alloy according to the requirement of internal control components, simultaneously adding aluminum-manganese-iron with the addition amount of 400Kg, keeping steel slag in the furnace at 30mm, blowing argon from the bottom for stirring, and continuously casting to form a continuous casting blank after the components and the temperature of the molten steel reach the requirements, wherein the special steel for the transmission shaft tube comprises the following materials in percentage by weight: 0.21% of C, 0.72% of Si, 2.54% of Mn, 0.009% of P, 0.004% of S, 0.72% of Cr, 0.53% of Mo, 0.51% of Cu, 0.11% of V, and the balance of Fe and unavoidable impurities.
The continuous casting blank adopts a hot feeding and hot charging process, and the heating temperature is 1160 ℃ so that the prior austenite grains are sufficiently coarse;
the rough rolling adopts a 3+3 mode, namely R1 rolling for 3 times and R2 rolling for 3 times, and the rough rolling enters a finishing mill group when the traveling temperature is 32S and the temperature is 960 ℃;
finish rolling: adopting 7 frames for hot continuous rolling, wherein the final rolling temperature is 825 ℃;
and (3) coiling: the coiling temperature is 385 ℃, and the special steel for the transmission shaft tube is obtained by conventional rolling through a hot continuous rolling mill unit.
Yield strength 755MPa, tensile strength 1060MPa and A of steel plate 50 =20%, yield ratio 0.71, 20 ℃ impact energy KV2 is respectively: 150J, 160J, 155J, the relative corrosion rate was 30%.
Referring to fig. 1, the steel sheet m+b (micro) in the present example has a grain size of 13.0 grade. Referring to fig. 5, the inclusions in this example were of class D0.5, and the remainder were of class 0.
Example 2
The steps of molten iron pretreatment, converter smelting, external refining, continuous casting and hot continuous rolling were employed to produce a steel dedicated to a driveshaft tube according to the method of example 1, except that: in converter smelting, oxygen is blown into desulfurized molten iron for 14min, and the tapping temperature is 1670 ℃; the added aluminum-manganese-iron in the LF furnace is 420kg, and the steel slag in the furnace is kept at 35mm. The steel for the transmission shaft pipe comprises the following materials in percentage by weight: 0.25% of C, 0.80% of Si, 2.6% of Mn, 0.008% of P, 0.004% of S, 0.60% of Mo, 1.60% of Cr, 0.60% of Cu, 0.12% of V, and the balance of Fe and unavoidable impurities.
The continuous casting blank adopts a hot feeding and hot charging process, and the heating temperature is 1175 ℃ so that the prior austenite grains are sufficiently coarse;
the rough rolling adopts a 3+3 mode, namely R1 rolling for 3 times and R2 rolling for 3 times, the rough rolling is performed for 45S when the traveling temperature is 965 ℃, and the rough rolling enters a finishing mill group;
finish rolling: 7 stands are adopted for hot continuous rolling, and the final rolling temperature is 840 ℃;
and (3) coiling: the coiling temperature is 395 ℃, and the special steel for the transmission shaft tube is obtained by conventional rolling through a hot continuous rolling mill unit.
Yield strength 782MPa, tensile strength 1095MPa and A of steel plate 50 =18.5%, yield ratio 0.71, 20 ℃ impact energy KV2 is respectively: 125J, 130J, 120J, the relative corrosion rate was 32%.
Referring to fig. 2, the steel sheet m+b (micro) grain size in the present example is 13.5 grade.
Example 3
The steps of molten iron pretreatment, converter smelting, external refining, continuous casting and hot continuous rolling were employed to produce a steel dedicated to a driveshaft tube according to the method of example 1, except that: in converter smelting, the smelting time is 15min, the tapping temperature is 1695 ℃, 490Kg of aluminum-manganese-iron is added in LF refining, and the steel slag in the converter is kept at 40mm. The special steel for the transmission shaft tube comprises the following materials in percentage by weight: 0.34% of C, 0.85% of Si, 2.85% of Mn, 0.006% of P, 0.003% of S, 0.71% of Mo, 1.73% of Cr, 0.72% of Cu, 0.15% of V, and the balance of iron and unavoidable impurities.
The continuous casting blank adopts a hot feeding and hot charging process, and the heating temperature is 1180 ℃ so that the prior austenite grains are sufficiently coarse;
the rough rolling adopts a 3+3 mode, namely R1 rolling for 3 times and R2 rolling for 3 times, the rough rolling is performed, and when the traveling temperature is 50S and the temperature is 970 ℃, the rough rolling enters a finishing mill group;
finish rolling: adopting 7 frames for hot continuous rolling, wherein the final rolling temperature is 845 ℃;
and (3) coiling: the coiling temperature is 405 ℃, and the special steel for the transmission shaft tube is obtained by conventional rolling through a hot continuous rolling mill unit.
The yield strength of the steel plate is 820MPa, the tensile strength is 630 MPa, A 50 =15%, yield ratio 0.72, 20 ℃ impact power KV2 is respectively: 105J, 110J, 118J, and the relative corrosion rate is 40%.
Referring to fig. 3, the steel sheet m+b (micro) grain size in the present example is 13.0 grade.
Example 4
The steps of molten iron pretreatment, converter smelting, external refining, continuous casting and hot continuous rolling were employed to produce a steel dedicated to a driveshaft tube according to the method of example 1, except that: in converter smelting, oxygen is blown for 16min, and the tapping temperature is 1700 ℃; the deoxidizer aluminum-manganese-iron added in the LF furnace is 500kg, and the steel slag in the furnace is kept at 45mm. The steel for the transmission shaft pipe comprises the following materials in percentage by weight: 0.40% of C, 0.99% of Si, 3.0% of Mn, 0.006% of P, 0.003% of S, 0.79% of Mo, 1.95% of Cr, 0.80% of Cu, 0.19% of V, and the balance of Fe and unavoidable impurities.
The continuous casting blank adopts a hot feeding and hot charging process, and the heating temperature is 1200 ℃ to ensure that the prior austenite grains are sufficiently coarse;
the rough rolling adopts a 3+3 mode, namely R1 rolling for 3 times and R2 rolling for 3 times, the rough rolling is carried out for 60S when the traveling temperature is 980 ℃, and the rough rolling enters a finishing mill group;
finish rolling: adopting 7 frames for hot continuous rolling, wherein the final rolling temperature is 855 ℃;
and (3) coiling: the coiling temperature is 410 ℃, and the special steel for the transmission shaft tube is obtained by conventional rolling through a hot continuous rolling mill unit.
Yield strength 890MPa, tensile strength 1180MPa and A of steel plate 50 =12%, yield ratio 0.75, 20 ℃ impact energy KV2 is respectively: 89J, 85J and 80J, and the relative corrosion rate is 42%.
Referring to fig. 4, the steel sheet m+b (micro) grain size in the present example is 13.5 grade.
Comparative example 1
Firstly, preprocessing, namely adding a mixed sulfur agent of magnesium powder and lime powder into a hot-metal ladle, wherein the weight percentage of the magnesium powder and the lime powder is 1:3.5, detecting frequently, and adding molten iron and scrap steel into a converter for smelting when the sulfur content in the molten iron is less than or equal to 0.005 percent after the pretreatment of the molten iron is finished; adding lime and light burned dolomite into a 180-ton top-bottom combined blown converter for slagging, then blowing oxygen for 18 minutes, tapping after oxygen blowing is completed, wherein the tapping temperature is 1650 ℃, and adding ferroniobium, ferrotitanium, ferrovanadium and the like in the tapping process to ensure that the molten steel components reach the tapping requirement, and the slag discharging amount requirement is less than or equal to 5 kg/ton of steel; adding molten steel into an LF refining furnace, adjusting the Nb, V and Ti contents in the alloy according to the requirement of internal control components, simultaneously adding aluminum for deoxidization, keeping the adding amount at 400Kg, keeping the steel slag in the furnace at 55mm, continuously casting after the components and the temperature of the molten steel meet the requirements, forming a continuous casting blank, heating, rough rolling, finish rolling and laminar cooling the continuous casting blank, and performing conventional rolling by a hot continuous rolling unit to obtain the steel special for the original transmission shaft tube. The special steel for the transmission shaft tube comprises the following materials in percentage by weight: 0.10% of C, 0.20% of Si, 1.65% of Mn, 0.015% of P, 0.010% of S, 0.075% of Nb, 0.06% of V, 0.13% of Ti, and the balance of iron and unavoidable impurities.
The yield strength of the steel plate is 700MPa, the tensile strength is 780MPa, A 50 =18%, yield ratio 0.90, 20 ℃ impact energy KV2 is respectively: 60J, 50J, 68J, the relative corrosion rate is 100%.
Referring to fig. 6, the steel sheet in this comparative example has a (f+m (micro)) grain size of 12.5 grade. Referring to fig. 7, nonmetallic inclusion in this comparative example: A0.5D2.0.
The foregoing disclosure is illustrative of the present invention and is not to be construed as limiting the scope of the invention, which is defined by the appended claims.

Claims (9)

1. The steel with tensile strength not less than 1000MPa is characterized by comprising the following components in percentage by weight: c:0.20-0.40%; si:0.70-1.0%; mn:2.50-3.0%; p is less than or equal to 0.010 percent; s is less than or equal to 0.005%; mo:0.50 to 0.80 percent; cr:1.50 to 2.0 percent; cu:0.50 to 0.80 percent; v:0.10 to 0.20 percent; the balance being iron and unavoidable impurities.
2. The steel with tensile strength not less than 1000MPa according to claim 1, wherein the thickness is 2.0-12.0 mm and the yield strength is 755-890 MPa; the impact energy KV2 at 20 ℃ is 80-160J; a is that 50 12-20%; the relative corrosion rate is 30-42%.
3. A method for preparing a steel with a tensile strength of not less than 1000MPa grade according to claim 1 or 2, comprising the steps of:
and (3) molten iron pretreatment: adding a desulfurizing agent to ensure that the sulfur content in the molten iron is less than or equal to 0.003 percent, and adding the molten iron into a converter;
smelting in a converter: the molten iron and scrap steel are added into a converter, and are blown by bottom blowing inert gas, lime and light burned dolomite are adopted for slagging, the oxygen blowing time is 12-16 minutes, when the weight percentage of C in the end point component is 0.18-0.25%, tapping is carried out at the temperature of 1660-1700 ℃, and alloying treatment is carried out in the tapping process;
LF refining: transferring molten steel smelted by the converter into an LF refining furnace, and adjusting the following components in the steel by weight percent: 0.50 to 0.80 percent of Cr:1.50 to 2.0 percent of Cu:0.50 to 0.80 percent of V:0.10 to 0.20 percent of deoxidizer is added, argon or nitrogen is blown into the bottom of the casting blank, and the casting blank is formed;
heating: heating at 1160-1200 deg.c to reach original austenite grain level of 5.0 or below;
rough rolling: r1 is rolled for 3-5 times, R2 is rolled for 3-5 times, and when the temperature is 960-980 ℃, the rolling mill enters a finishing mill group;
finish rolling: adopting multi-frame hot continuous rolling, wherein cooling water is input between frames, and the final rolling temperature of the finish rolling is 825-855 ℃;
and (3) coiling: the coiling temperature is 385-415 ℃.
4. The method for preparing steel with tensile strength not less than 1000MPa according to claim 3, wherein the desulfurizing agent consists of magnesium powder and lime powder, and the weight ratio of the magnesium powder to the lime powder is 1:4.0 to 5.0;
the slag discharging amount in converter smelting is less than or equal to 5 kg/ton of steel.
5. The method for preparing steel with tensile strength not less than 1000MPa according to claim 3, wherein the deoxidizer consists of aluminum-manganese-iron, and the weight ratio of aluminum-manganese-iron in the deoxidizer is Al: mn: fe=40: 30:30;
the molten steel top slag in the LF refining furnace is kept between 30mm and 40mm.
6. The method for producing steel having a tensile strength of 1000MPa or more according to claim 3, wherein the soaking time of the continuous casting slab in the hot-dip casting process is 60 to 70 minutes.
7. The method for producing steel having a tensile strength of 1000MPa or more according to claim 3, wherein the floating stand-by time of rough rolling is 30S to 60S.
8. Use of a steel having a tensile strength of not less than 1000MPa grade according to any one of claims 1 to 2 or a steel having a tensile strength of not less than 1000MPa grade prepared by a method according to any one of claims 3 to 7 in a propeller shaft of an automobile.
9. The use of a steel with a tensile strength of not less than 1000MPa in a propeller shaft for an automobile according to claim 8, wherein the propeller shaft has a thickness of 2.0 to 12.0mm, a yield strength of 750 to 900MPa, a tensile strength of 1050 to 1180MPa, A 50 12-20%.
CN202211659025.3A 2022-12-22 Steel with tensile strength of 1000MPa and preparation method and application thereof Active CN116121642B (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002121643A (en) * 2000-10-16 2002-04-26 Hitachi Metals Ltd Steel for diecasting die, method for producing diecasting die composed by using the same and diecasting die
CN108754304A (en) * 2018-04-24 2018-11-06 北京交通大学 A kind of corrosion-resistant bainitic steel, wheel and manufacturing method comprising it
CN110724877A (en) * 2019-10-30 2020-01-24 鞍钢股份有限公司 1180MPa grade high-plasticity bainite complex phase steel plate for automobile and preparation method thereof
CN111793777A (en) * 2020-08-20 2020-10-20 山东华星新材料科技有限公司 1000 MPa-level hot-rolled high-strength corrosion-resistant dual-phase steel plate and preparation method thereof
CN113278777A (en) * 2021-01-11 2021-08-20 江阴兴澄特种钢铁有限公司 Method for controlling steel strip-shaped structure of alloy structure

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002121643A (en) * 2000-10-16 2002-04-26 Hitachi Metals Ltd Steel for diecasting die, method for producing diecasting die composed by using the same and diecasting die
CN108754304A (en) * 2018-04-24 2018-11-06 北京交通大学 A kind of corrosion-resistant bainitic steel, wheel and manufacturing method comprising it
CN110724877A (en) * 2019-10-30 2020-01-24 鞍钢股份有限公司 1180MPa grade high-plasticity bainite complex phase steel plate for automobile and preparation method thereof
CN111793777A (en) * 2020-08-20 2020-10-20 山东华星新材料科技有限公司 1000 MPa-level hot-rolled high-strength corrosion-resistant dual-phase steel plate and preparation method thereof
CN113278777A (en) * 2021-01-11 2021-08-20 江阴兴澄特种钢铁有限公司 Method for controlling steel strip-shaped structure of alloy structure

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