CN114855078A - Inverse phase change composite microalloyed light high-strength steel and production method thereof - Google Patents

Inverse phase change composite microalloyed light high-strength steel and production method thereof Download PDF

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CN114855078A
CN114855078A CN202210417222.8A CN202210417222A CN114855078A CN 114855078 A CN114855078 A CN 114855078A CN 202210417222 A CN202210417222 A CN 202210417222A CN 114855078 A CN114855078 A CN 114855078A
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steel
strength steel
reverse phase
light high
strength
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余灿生
常智渊
苏冠侨
郑之旺
王敏莉
郑昊青
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Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
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Pangang Group Panzhihua Iron and Steel Research Institute 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
    • 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
    • C21D1/26—Methods of annealing
    • 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
    • C21D6/005—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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/02—Hardening by precipitation
    • 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
    • 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
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • 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
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • 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
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • 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
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/001—Austenite
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/008—Martensite

Abstract

The invention relates to inverse phase change composite microalloyed light high-strength steel and a production method thereof, belonging to the technical field of metallurgical production processes. Provides the light high-strength steel with relatively good processing performance and the production method thereof. The light high-strength steel is a hot-rolled steel plate comprising the following components in parts by weight: 0.10% -0.28%, Si: 0.15 to 0.50%, Mn: 3.0-4.2%, P is less than or equal to 0.020%, S is less than or equal to 0.010%, Als: 2.7% -3.3%, Nb: 0.010-0.10%, V: 0.022-0.080%, Ti: 0.01-0.08%, and the balance of Fe and inevitable impurities; the production method comprises the steps of smelting, hot rolling and reverse phase transformation annealing.

Description

Reverse phase change composite microalloyed light high-strength steel and production method thereof
Technical Field
The invention relates to inverse phase change composite microalloyed light high-strength steel, and belongs to the technical field of metallurgical production processes. The invention also relates to a production method for the light high-strength steel.
Background
In the production process of automobiles and other industries, some structural steel parts with certain requirements on light weight are often needed, but the strength of the light weight steel parts cannot ensure the rigidity of the structure, so that the density of high-strength steel is needed to be reduced to meet the requirements of the light weight structural parts. The prior art generally meets the requirements of the developing industry and manufacturing industry by changing the types and amounts of components in steel to obtain the desired low density steel. Among them, aluminum is added to high manganese steel, and light Fe-Mn-Al-C steel having low density, good ductility, corrosion resistance, etc. can be used because aluminum has low density, good ductility, and easily formed oxide film on the surface. And by adjusting the addition amount of the manganese-aluminum metal, the material with good mechanical properties can be obtained, so that the density can be reduced, and meanwhile, the better structure property and mechanical properties can be maintained. However, there is no fixed range for adjusting various components in the material, and it is difficult to determine the composition range of high performance value, and on the other hand, the performance of the steel depends not only on the composition of the material, but also on the preparation process of the steel, therefore, how to obtain a suitable material composition range and adopt a reasonable preparation process for the material in the composition range is an important issue to be researched.
The invention with publication number CN 111926264A discloses a low-density steel and a manufacturing method thereof, wherein the low-density steel comprises the following chemical components in percentage by weight: 0.8 to 1.6 percent of C, 6.0 to 9.5 percent of Al, the sum of Mn + Nb + V + Mo + Ti is less than or equal to 8 percent, and the balance of Fe and inevitable impurity elements. Heating the hot rolled steel to a temperature above Ac1 and below the critical temperature point Ac3 within a temperature range of 20-130 ℃, and preserving heat for 1-60 min; cooling to 0-50 deg.C below the critical temperature point Ac1, cooling at 0.1-200 deg.C/h, and cooling to room temperature. The technology of the application has the defects that the welding performance of the material with the overhigh C content is poor, the rolling process is fuzzy and has no referential property, the content of noble metal is high (Mn + Nb + V + Mo + Ti is less than or equal to 8%), the alloy cost is high, and the like.
The invention with publication number CN 110438315A discloses a heat treatment method for improving the mechanical property of TRIP steel in Fe-Mn-Al-C series, which comprises the following chemical components in percentage by weight: 0.1-0.2% of C, 12-15% of Mn, 2-3% of Al, and the balance of Fe and inevitable impurities. Heating the steel ingot to 1200-1230 ℃, and forging the steel ingot into a steel billet after heat preservation for 2-2.5 hours; and (3) placing the forged blank into a heating furnace, preserving heat for 2-2.5h at the temperature of 1200-1250 ℃, then starting rolling, wherein the initial rolling temperature is 1150-1200 ℃, the final rolling temperature is 850-900 ℃, quenching is carried out at the cooling speed of not less than 100 ℃/h to 590-750 ℃, preserving heat for 1-1.5h, then water quenching is carried out until the tempering temperature of the workpiece at room temperature is 200-220 ℃, preserving heat for 30-50min, and then air cooling is carried out to the room temperature. The alloy cost is increased due to the fact that the alloy contains the precious alloy Nb and relatively more Cr, the alloy is rapidly cooled to 590-750 ℃ after hot rolling, the post-heat-preservation re-quenching process is complex, and the implementation difficulty is high.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the invention provides reverse phase change composite microalloyed light high-strength steel with relatively good processing performance and a production method for the light high-strength steel.
The technical scheme adopted for solving the technical problems is as follows: the inverse phase change composite microalloyed light high-strength steel is a hot-rolled steel plate comprising the following components in parts by weight: 0.10% -0.28%, Si: 0.15 to 0.50%, Mn: 3.0-4.2%, P is less than or equal to 0.020%, S is less than or equal to 0.010%, Als: 2.7% -3.3%, Nb: 0.010-0.10%, V: 0.022-0.080%, Ti: 0.01-0.08%, and the balance of Fe and inevitable impurities;
the yield strength of the light high-strength steel subjected to reverse phase transformation annealing is 570-700 MPa, the tensile strength is 770-890 MPa, and the elongation A50 is 31.0-37.5%; the structure of the steel plate consists of 9-14% of strip delta ferrite, 38-44% of ferrite, 32-46% of martensite and 6-10% of retained austenite.
Further, the components in parts by weight are as follows: 0.18 to 0.22%, Si: 0.26 to 0.33%, Mn: 3.3-3.7%, Al: 2.9-3.2%, P is less than or equal to 0.015%, S is less than or equal to 0.010%, Nb: 0.030-0.045%, V: 0.050 to 0.065%, Ti: 0.02-0.04%, and the balance of Fe and unavoidable impurities.
The production method for the light high-strength steel at least comprises the steps of smelting, hot rolling and reverse phase transformation annealing;
wherein the smelting process comprises the following steps: smelting according to the chemical components of the light high-strength steel, and casting into a plate blank;
a hot rolling procedure: slowly heating the plate blank to 1230 +/-20 ℃, preserving heat for 5 hours, discharging, removing surface iron scale by using dephosphorization equipment, rolling the strip steel to the corresponding thickness specification by using a hot rolling unit, wherein the final rolling temperature is 870-plus-930 ℃, and the coiling temperature is 660-plus-720 ℃;
reverse phase transition annealing: and slowly heating the strip steel to 810-840 ℃ by using a hood-type annealing furnace at a speed of 4-7 ℃/min, preserving heat for 4-6 hours, and cooling the strip steel to room temperature along with the furnace.
Preferably, the C, Mn and Al elements in the strip after the reverse phase transformation annealing act together and exist in a kappa-carbide form, wherein the chemical formula of the kappa-carbide is (Fe, Mn) 3 AlC。
The invention has the beneficial effects that: the invention reduces the density of steel by adding light elements C, Al, etc., and reduces the weight on the basis of ensuring the strength and plasticity of the product, thereby promoting the light weight of the steel for automobiles. Meanwhile, Al is used for inhibiting the precipitation of cementite, so that carbon elements are enriched in the residual austenite, and the hardenability is improved. The addition of a certain amount of Mn element enlarges the adverse effects of narrowing the austenite phase region in the austenite region and the austenite phase region of the Al added band. The micro-alloy elements (Nb, V and Ti) are added in a compounding way to refine grains and precipitate out, so that the strong plasticity of the product is effectively improved. The transformation from martensite to austenite is realized through reverse phase transformation annealing, the deformation induced plasticity effect is played in the plastic deformation process, the elongation after fracture of the product is effectively improved, and good strong plasticity is obtained. By the production method of the light high-strength steel, the yield strength is 570-700 MPa, the tensile strength is 770-890 MPa, and the elongation A50 is 31.0-37.5%; the structure of the steel consists of 9 to 14 percent of strip delta ferrite, 38 to 44 percent of ferrite, 32 to 46 percent of lath martensite and 6 to 10 percent of residual austenite.
Drawings
FIG. 1 is a metallographic photograph of a strip steel related to the light-weight high-strength steel of the present invention;
FIG. 2 is a scanning photograph of the steel strip involved in the light high-strength steel of the present invention;
FIG. 3 is a distribution diagram of the residual austenite of the steel strip involved in the light high-strength steel of the present invention.
Detailed Description
As shown in fig. 1, 2 and 3, the reverse phase transformation composite micro-alloying light high-strength steel is a hot-rolled steel plate comprising the following components in parts by weight: 0.10% -0.28%, Si: 0.15 to 0.50%, Mn: 3.0-4.2%, P is less than or equal to 0.020%, S is less than or equal to 0.010%, Als: 2.7% -3.3%, Nb: 0.010-0.10%, V: 0.022-0.080%, Ti: 0.01-0.08%, and the balance of Fe and inevitable impurities;
the yield strength of the light high-strength steel subjected to reverse phase transformation annealing is 570-700 MPa, the tensile strength is 770-890 MPa, and the elongation A50 is 31.0-37.5%; the structure of the steel plate consists of 9-14% of strip delta ferrite, 38-44% of ferrite, 32-46% of martensite and 6-10% of retained austenite.
More specifically, the components in parts by weight are as follows: 0.18 to 0.22%, Si: 0.26 to 0.33%, Mn: 3.3-3.7%, Al: 2.9-3.2%, P is less than or equal to 0.015%, S is less than or equal to 0.010%, Nb: 0.030-0.045%, V: 0.050 to 0.065%, Ti: 0.02-0.04%, and the balance of Fe and unavoidable impurities.
The production method for the light high-strength steel at least comprises the steps of smelting, hot rolling and reverse phase transformation annealing;
wherein the smelting process comprises the following steps: smelting according to the chemical components of the light high-strength steel, and casting into a plate blank;
a hot rolling procedure: slowly heating the plate blank to 1230 +/-20 ℃, preserving heat for 5 hours, discharging, removing surface iron scale by using dephosphorization equipment, rolling the strip steel to the corresponding thickness specification by using a hot rolling unit, wherein the final rolling temperature is 870-plus-930 ℃, and the coiling temperature is 660-plus-720 ℃;
reverse phase transition annealing: and slowly heating the strip steel to 810-840 ℃ by using a hood-type annealing furnace at a speed of 4-7 ℃/min, preserving heat for 4-6 hours, and cooling the strip steel to room temperature along with the furnace.
After reverse phase transition annealing, C, Mn and Al elements in the strip steel jointly act and then exist in a kappa-carbide form, wherein the chemical formula of the kappa-carbide is (Fe, Mn) 3 AlC。
The function of the alloy elements in the inverse phase change composite microalloying light high-strength steel is as follows:
carbon: c is an important austenite element in steel, and can stabilize the austenite structure and also promote the reduction of density. Meanwhile, C can react with microalloy elements in steel to generate nano-scale carbide and can react with Mn and Al elements to generate kappa-carbide ((Fe, Mn) 3 AlC) and the two act together to produce precipitation strengthening and improve the strength of the steel. The C content is too low, so that the austenite structure in the steel is unstable, the precipitation amount of carbides in the steel is reduced, and the strength and the toughness of the low-density steel are reduced. However, since too high a C content promotes the formation of coarse kappa carbides at austenite grain boundaries and deteriorates the elongation of the low-density steel, the C content in the present invention is 0.12 to 0.28%, preferably 0.18 to 0.22%.
Silicon: si can be dissolved in solid solutionThe strength of the steel is improved in ferrite and austenite, the effect is second to C, P, and the steel is stronger than elements such as Mn, Cr, Ti, Ni and the like; si can also inhibit carbide in ferrite from being precipitated, so that solid-solution C atoms are fully enriched in austenite, and the Si content with excessively low stability is improved, and residual austenite is difficult to obtain at room temperature. However, when the content of Si is too high, the surface iron scale formed by Si in the heating furnace is difficult to remove, so that the dephosphorization difficulty is increased; meanwhile, SiO is easily enriched and formed on the surface in the annealing process 2 Resulting in surface defects such as skip plating. Therefore, the Si content of the present invention is 0.15 to 0.50%, preferably 0.26 to 0.33%.
Manganese: mn is an austenitizing element, and the addition of the Mn element can enlarge an austenite phase region, improve austenite content, improve the stacking fault energy of steel, inhibit martensite phase transformation, generate dense twin crystals in the deformation process, and effectively improve the elongation of the steel, but the cost is increased after the manganese content is greatly increased, and the segregation is serious. Therefore, the Mn content is 3.0% to 4.2%, preferably 3.3 to 3.7% in the present invention.
Aluminum: the density of Al is 2.7g/cm 3 Much lower than 7.85g/cm 3 The density of the Fe can be obviously reduced. The Al content can also obviously improve the heat deformation resistance of the steel, improve the corrosion resistance of the steel and delay dynamic cracking, and the Al can also obviously improve the fault energy of the steel and change the deformation mechanism, so that the medium manganese steel containing the Al can have a certain buffer effect when violent collision occurs. However, considering that Al is a strong ferrite element, too high Al content tends to promote the formation of ferrite phase and to reduce the austenite phase content. Therefore, the Al content in the present invention is 2.7% to 3.3%, preferably 2.9% to 3.2%.
Niobium: nb, as a strong carbide-forming element, combines with C in steel to form a second phase of NbC and inhibits the movement of dislocations to produce a precipitation strengthening effect. NbC precipitates also play a role in nailing and rolling on crystal boundaries, so that recrystallization movement is prevented, growth of austenite grains is inhibited, and the effect of refining the grains is achieved. However, in order to save cost and reduce the influence on the specific gravity of the low-density steel, the content of Nb is not preferably too high, and therefore the content of Nb is set to be in the range of 0.010 to 0.10% by mass, preferably 0.030 to 0.045% by mass.
Vanadium: mainly utilizes the fine grain strengthening and precipitation strengthening functions of V. V is sufficiently dissolved in austenite and fine V (C, N) particles are precipitated from proeutectoid ferrite, and this precipitation can significantly improve the strength of steel. Furthermore, the high V (C, N) solubility in austenite allows the use of lower reheating temperatures, which means lower production costs. The deformation mechanism of the steel is mainly dislocation slippage, and fine precipitate phases can be separated out from the steel by adding V, and the precipitate phases can improve the nucleation rate and prevent the growth of crystal grains to refine the crystal grains; on the other hand, the dislocation movement can be blocked to improve the strength, so that good comprehensive mechanical properties are finally obtained. Therefore, the V content is set to 0.022 to 0.080% by mass, preferably 0.050 to 0.065%. Titanium: ti is very active and is easy to combine with O, and part of Ti can play the role of a deoxidizer in the smelting process; secondly, the titanium carbide has strong affinity with C and is a strong carbide forming element, and the titanium carbide in the steel can play the roles of refining strengthening, precipitation strengthening and the like, so that the strength of the steel can be improved; however, if the content is too high, the diffusion rate of C in austenite can be remarkably reduced, the content of C in austenite is reduced, the stability of a matrix is reduced, and the plasticity is reduced; therefore, the Ti content is set to 0.01 to 0.08% by mass, preferably 0.02 to 0.04%.
As described above, the present invention can reduce the density of steel by adding the lightweight element C, Al, etc., thereby reducing the weight of the steel while ensuring the strength and plasticity of the product, and thus promoting the weight reduction of the steel for automobiles. Meanwhile, Al is used for inhibiting the precipitation of cementite, so that carbon elements are enriched in the residual austenite, and the hardenability is improved. The addition of a certain amount of Mn element enlarges the adverse effects of narrowing the austenite phase region in the austenite region and the austenite phase region of the Al added band. The micro-alloy elements (Nb, V and Ti) are added in a compounding way to refine grains and precipitate out, so that the strong plasticity of the product is effectively improved. The transformation from martensite to austenite is realized through reverse phase transformation annealing, the deformation induced plasticity effect is played in the plastic deformation process, the elongation after fracture of the product is effectively improved, and good strong plasticity is obtained. By the production method of the light high-strength steel, the yield strength is 570-700 MPa, the tensile strength is 770-890 MPa, and the elongation A50 is 31.0-37.5%; the structure of the steel consists of 9 to 14 percent of strip delta ferrite, 38 to 44 percent of ferrite, 32 to 46 percent of lath martensite and 6 to 10 percent of residual austenite.
Example 1
The present example provides two groups of composite microalloyed light high-strength steels, the chemical compositions of which are shown in table 1;
TABLE 1 inverse phase transition composite microalloyed light high strength steel chemical composition (wt.%)
Numbering C Si Mn P S Nb V Ti Als
1 0.185 0.27 3.53 0.013 0.009 0.035 0.057 0.030 3.06
2 0.205 0.29 3.39 0.009 0.006 0.038 0.052 0.025 2.97
The preparation method of the inverse phase change composite microalloyed light high-strength steel comprises the following specific processes:
A. smelting: preparing a steel slab of the composite microalloyed light steel shown in the table 1 by a smelting process;
B. a hot rolling procedure: heating, hot rolling and hot coiling the plate blank, wherein the specific hot rolling process parameters are shown in a table 2;
TABLE 2 main technological parameters of hot rolling of light high-strength steel by reverse phase transformation composite micro-alloying rolling
Numbering The initial rolling temperature/. degree.C Final Rolling temperature/. degree.C Coiling temperature/. degree.C
1 1055 922 697
2 1037 917 685
C. Reverse phase transition annealing: the strip steel is slowly heated to a target temperature by using a hood-type annealing furnace, is cooled along with the furnace after being kept warm for a period of time, and the parameters are shown in Table 3
TABLE 3 inverse phase transition composite microalloying light high-strength steel main technological parameters
Numbering Heating speed/min Annealing temperature/. degree.C Incubation time/. degree.C
1 5.2 830 5.0
2 5.5 824 4.5
The microstructure of the case 1 composite microalloyed light high-strength steel prepared by the process is shown in fig. 1, the performance of the light high-strength steel is tested according to GB/T228-2010 metal material room temperature tensile test method, and the mechanical properties are shown in the following table 4:
TABLE 4 mechanical properties of inverse phase transition composite microalloyed rolled light high-strength steel
Figure BDA0003605304420000061

Claims (4)

1. The reverse phase change composite microalloyed light high-strength steel is characterized in that: the light high-strength steel is a hot-rolled steel plate comprising the following components in parts by weight: 0.10% -0.28%, Si: 0.15 to 0.50%, Mn: 3.0-4.2%, P is less than or equal to 0.020%, S is less than or equal to 0.010%, Als: 2.7% -3.3%, Nb: 0.010-0.10%, V: 0.022-0.080%, Ti: 0.01-0.08%, and the balance of elements are Fe and inevitable impurities;
the yield strength of the light high-strength steel after the reverse phase transformation annealing is 570-700 MPa, the tensile strength is 770-890 MPa, and the elongation A50 is 31.0-37.5%; the structure of the steel plate consists of 9 to 14 percent of strip delta ferrite, 38 to 44 percent of ferrite, 32 to 46 percent of lath martensite and 6 to 10 percent of residual austenite.
2. The reverse phase transition composite microalloyed light weight high strength steel as claimed in claim 1, wherein: the components in parts by weight are as follows: 0.18 to 0.22%, Si: 0.26 to 0.33%, Mn: 3.3-3.7%, Al: 2.9-3.2%, P is less than or equal to 0.015%, S is less than or equal to 0.010%, Nb: 0.030-0.045%, V: 0.050 to 0.065%, Ti: 0.02-0.04%, and the balance of Fe and unavoidable impurities.
3. A production method for the light weight, high strength steel according to claim 1 or 2, characterized by: the production method at least comprises the steps of smelting, hot rolling and reverse phase transformation annealing;
wherein the smelting process comprises the following steps: smelting according to the chemical components of the light high-strength steel, and casting into a plate blank;
a hot rolling procedure: slowly heating the plate blank to 1230 +/-20 ℃, preserving heat for 5 hours, discharging, removing surface iron scale by using dephosphorization equipment, rolling the strip steel to the corresponding thickness specification by using a hot rolling unit, wherein the final rolling temperature is 870-plus-930 ℃, and the coiling temperature is 660-plus-720 ℃;
reverse phase transition annealing: and slowly heating the strip steel to 810-840 ℃ by using a hood-type annealing furnace at a speed of 4-7 ℃/min, preserving heat for 4-6 hours, and cooling to room temperature along with the furnace.
4. A method for producing a lightweight, high-strength steel according to claim 3, characterized in that: the C, Mn and Al elements in the strip steel after the reverse phase transition annealing act together and then exist in a kappa-carbide form, wherein the chemical formula of the kappa-carbide is (Fe, Mn) 3 AlC。
CN202210417222.8A 2022-04-20 2022-04-20 Inverse phase change composite microalloyed light high-strength steel and production method thereof Pending CN114855078A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117265415A (en) * 2023-11-17 2023-12-22 东北大学 Acid-washing-free low-density steel and preparation method thereof

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0559429A (en) * 1991-09-03 1993-03-09 Nippon Steel Corp Production of high strength cold rolled sheet of dual-phase steel excellent in workability
CN111575580A (en) * 2020-05-08 2020-08-25 钢铁研究总院 High-strength-toughness and high-strength-ductility automobile steel and preparation method thereof

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0559429A (en) * 1991-09-03 1993-03-09 Nippon Steel Corp Production of high strength cold rolled sheet of dual-phase steel excellent in workability
CN111575580A (en) * 2020-05-08 2020-08-25 钢铁研究总院 High-strength-toughness and high-strength-ductility automobile steel and preparation method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117265415A (en) * 2023-11-17 2023-12-22 东北大学 Acid-washing-free low-density steel and preparation method thereof
CN117265415B (en) * 2023-11-17 2024-01-30 东北大学 Acid-washing-free low-density steel and preparation method thereof

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