CN111218621A - TRIP steel with ultrahigh strength-elongation product and preparation method thereof - Google Patents
TRIP steel with ultrahigh strength-elongation product and preparation method thereof Download PDFInfo
- Publication number
- CN111218621A CN111218621A CN202010018674.XA CN202010018674A CN111218621A CN 111218621 A CN111218621 A CN 111218621A CN 202010018674 A CN202010018674 A CN 202010018674A CN 111218621 A CN111218621 A CN 111218621A
- Authority
- CN
- China
- Prior art keywords
- strength
- elongation
- steel
- trip steel
- rolling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- 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
- 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
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0231—Warm 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
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
Abstract
The invention relates to TRIP steel with ultrahigh product of strength and elongation, which comprises the following chemical components in percentage by mass: 0.16-0.28% of C, 8-12.5% of Mn, 1.5-3% of Al, 0-0.005% of S, 0-0.008% of P, and the balance of Fe and inevitable impurities. The preparation method comprises the following steps: smelting according to the chemical components of the TRIP steel, and casting into an ingot; firstly, preserving heat for 2 +/-0.5 hours within the temperature range of 1150-1250 ℃ to homogenize the structure, then forging the cast ingot into a plate blank, and cooling in the air; carrying out tissue homogenization treatment on the plate blank at the temperature of 1120-1180 ℃ for 2 +/-0.5 hours, then carrying out hot rolling to obtain a hot rolled plate, and cooling to room temperature in an air cooling mode; carrying out second tissue homogenization treatment, heating the hot rolled plate to 600-650 ℃, preserving heat for 2 +/-0.5 hours, carrying out warm rolling at 600-650 ℃, and air-cooling to room temperature; keeping the temperature at 575-625 ℃ for 40 min-1 h, and cooling in air to room temperature. The TRIP steel has excellent mechanical property, and the product of strength and elongation can reach 70 GPa%, thereby meeting the requirements of low-density advanced automobile steel.
Description
Technical Field
The invention relates to the technical field of high-strength steel, in particular to TRIP steel with ultrahigh product of strength and elongation and a preparation method thereof.
Background
With the development of society, the demand of materials for the automobile industry is increasing, but with the increased competition of the material market, the materials required by automobile manufacturing must have excellent service performance to comply with the development of the material industry. As a steel material which is a basic constituent of an automobile, high strength, a product of strength and elongation and a large elongation are the directions of development, and reduction of the production cost of an automobile material is one of the main means for obtaining the profit of automobile manufacture.
The TRIP steel is an ultra-strength steel in which the plasticity of the steel is improved by transformation induction and plastic deformation of the steel structure, and has mechanical properties characteristic of high strength. When the steel is deformed by external impact, austenite in the crack region induces formation of martensite, and nucleation of the martensite requires absorption of a large amount of energy, thereby inhibiting crack growth and propagation and improving strength and toughness of the steel. Because TRIP steel has the TRIP effect, the TRIP steel is commonly used for anti-collision parts such as automobile bottom plates, ABC columns, bumpers and the like.
The product of strength and elongation is the product of the room temperature tensile strength and the total elongation at break of the material, and is often used as one of the determination indexes of the comprehensive performance of the structural metal material. However, the strength and plasticity (expressed by elongation) of a metal material are generally not compatible, i.e., if high strength is obtained, the plasticity is reduced; conversely, an increase in plasticity decreases the strength, which leads to a generally lower product of strength and elongation of the material. In order to obtain a metal material with a high strength-elongation product, it is necessary to adjust the composition of the alloy chemical composition and to develop a better heat treatment process technology.
Disclosure of Invention
In view of the problems in the prior art, the invention provides TRIP steel with ultrahigh product of strength and elongation, which adopts the technical scheme that the TRIP steel comprises the following chemical components in percentage by mass: 0.16-0.28% of C, 8-12.5% of Mn, 1.5-3% of Al, 0-0.005% of S, 0-0.008% of P, and the balance of Fe and inevitable impurities.
The invention also provides a preparation method of the TRIP steel with the ultrahigh product of strength and elongation, which adopts the technical scheme that the method comprises the following steps:
smelting: smelting according to the chemical components of the TRIP steel, and casting into an ingot;
forging: firstly, preserving heat for 2 +/-0.5 hours within the temperature range of 1150-1250 ℃ to homogenize the structure, then forging the cast ingot into a plate blank, and cooling in the air;
hot rolling: carrying out tissue homogenization treatment on the plate blank at the temperature of 1120-1180 ℃ for 2 +/-0.5 hours, then carrying out hot rolling to obtain a hot rolled plate, and cooling to room temperature in an air cooling mode;
warm rolling: carrying out second tissue homogenization treatment, heating the hot rolled plate to 600-650 ℃, preserving heat for 2 +/-0.5 hours, carrying out warm rolling at 600-650 ℃, and air-cooling to room temperature;
and (3) annealing the two-phase region: and (3) preserving the heat at the temperature of 575-625 ℃ for 40 min-1 h, and air-cooling to room temperature to obtain the TRIP steel with ultrahigh product of strength and elongation.
The smelting equipment in the smelting step is a vacuum induction furnace, the smelting material obtains induction current under the vacuum condition by the electromagnetic induction principle so as to achieve the heating purpose, and the temperature in the furnace is 1550-1650 ℃.
In the forging step, the thickness of the forged plate blank is 18-22 mm.
In the hot rolling step, the thickness of the hot rolled plate after hot rolling is 5mm, and the hot rolling pass is 7-8 times.
The initial rolling temperature is 1120-1180 ℃, and the final rolling temperature is 900-950 ℃.
In the warm rolling step, the thickness of the obtained warm rolled plate after warm rolling is 2mm, and the number of warm rolling passes is 3-4.
In the two-phase region annealing step, the heating speed in the heat treatment process is 2-8 ℃/s.
In the present invention, the effect of each chemical element in the TRIP steel is analyzed as follows:
carbon is an austenite forming and stabilizing element and plays a role in interstitial solid solution strengthening, the stability of austenite is improved along with the increase of the carbon content in the austenite, but the carbon content in the low-density high-strength steel cannot be too high, otherwise, component segregation can be caused during casting, carbide precipitation can be caused, the welding performance can be influenced, certain К -carbide can be generated when the Fe-Mn-Al-C series low-density steel alloyed with Al and C is aged within the temperature range of 500-750 ℃, К -carbide has great influence on the strength and plasticity of the series of steel, the uniformly distributed superfine К -carbide can play a role in strengthening, and the plasticity of the low-carbon steel cannot be obviously reduced, but the coarse К phase can cause brittle fracture of the steel and seriously influence the impact toughness of the steel, and the carbon content is limited to be within 0.16-0.28% by combining various factors of the influence of the C on the material performance.
Mn: manganese is a main alloy element of the Fe-Mn-Al-C series low-density steel, has great influence on the stability of austenite, can improve the stability of the austenite, plays a role in solid solution strengthening, reduces the phase transition temperature of the austenite, reduces the transformation rate of the austenite to martensite, and has better effect of reducing the martensite critical transformation rate along with the improvement of the manganese content. Mn also influences the stacking fault energy of the Fe-Mn-Al-C series low-density steel, so that compact twin crystals can be generated when the steel is deformed by external force, and the elongation of the series low-density steel is obviously improved. However, excessively high Mn content causes component segregation and reduced weldability, and has a negative effect on improvement of the comprehensive properties of manganese steel. The Mn content of the invention is 8-12.5%.
Al: the aluminum can reduce the austenite phase region, can increase the temperature of A3, effectively enhance the stability of austenite, increase the stacking fault energy of the Fe-Mn-Al-C series low-density steel, influence the generation of deformation twin crystals and be beneficial to the formation of the deformation twin crystals, thereby improving the strong plasticity of the Fe-Mn-Al-C series low-density steel. The certain aluminum content can obviously improve the heat deformation resistance of the steel and delay dynamic recrystallization, so that austenite grains are refined after dynamic recrystallization. However, the high aluminum content is not conducive to metal casting and further control of the aluminum content is required. Therefore, the Al content of the invention is 1.5-3%.
P, S: phosphorus and sulfur are unfavorable elements for steel forming. Sulfur exists in steel in the form of sulfide inclusions such as FeS, MnS, etc., and sulfide is generally distributed in grain boundaries, and is melted when the temperature reaches its melting point, resulting in cracking when the steel is hot deformed during rolling and forging. Phosphorus seriously affects the cold deformability of steel, and as the content of phosphorus increases, the effect is sharply increased and cold embrittlement occurs. Therefore, the invention contains trace or no sulfur and phosphorus elements so as to improve the mechanical property of the ultrahigh-strength TRIP steel.
The invention has the following beneficial effects: the invention optimizes the chemical components, improves the stability of austenite by C and Mn elements, reduces the transformation rate of austenite to martensite, plays a role in solid solution strengthening and enhances the strength of steel. Because Si is unfavorable for the production of the TRIP steel plate, Al is used for replacing Si, the precipitation of carbide is inhibited, the tensile property of the steel can be improved, and the addition of the Al can effectively reduce the density of the steel and promote the lightweight development of the steel. Meanwhile, the chemical components of the invention do not contain noble alloy elements such as Cr, Mo, Ti and the like, thereby reducing the production cost.
According to the invention, through an optimization process, warm rolling is a rolling deformation process of metal in a temperature range below the recrystallization temperature and above the recovery temperature, and the grain structure obtained by adopting the warm rolling deformation process is fine, so that fine grain strengthening is facilitated, and the strength of the rolled material is higher. Therefore, the work hardening of the material is recovered in the warm rolling process, the plasticity of the material is improved to a certain extent, and the deformability is improved to some extent. Compared with cold rolling, the warm rolling deformation process has higher plasticity and elongation of the obtained material. The heat treatment step is to utilize the two-phase region annealing process to recrystallize ferrite, generate austenite reverse transformation, refine grains of a steel structure, improve the stability of austenite and enhance the TRIP effect during austenite transformation. The method combines warm rolling with annealing treatment of a two-phase region, greatly improves the content of the residual austenite in an annealed structure, and simultaneously accurately adjusts the mechanical stability of the residual austenite, so that the structure can gradually generate a TRIP effect when deformed. The steel sheet has excellent formability while improving yield and tensile strength.
The TRIP steel with the ultrahigh product of strength and elongation has excellent comprehensive mechanical properties, the tensile strength is 1300-1450 MPa, the elongation is 50-65%, and the product of strength and elongation can reach 70 GPa%. The performance is excellent, the requirement of low-density advanced automobile steel is met, the steel is suitable for the development of the steel industry, and the steel has great market value.
Further, a vacuum induction furnace is adopted for smelting, the smelting material obtains induction current through the electromagnetic induction principle under the vacuum condition so as to achieve the heating purpose, and the smelting is carried out under the condition of isolating air, so that elements such as N, O in the air are prevented from reacting with ferromanganese to generate oxides and nitrides, and the possibility of hot brittleness and aging brittleness is reduced.
Drawings
FIG. 1 is a process flow diagram of the method for producing a TRIP steel with ultra-high product of strength and elongation according to the present invention;
FIG. 2 is an SEM photograph of the ultra-high product of strength and elongation TRIP steel of example 1 before deformation;
FIG. 3 is an SEM photograph of the deformed TRIP steel of example 1 of the present invention;
FIG. 4 is an XRD pattern of the TRIP steel of ultra-high product of strength and elongation of the invention in example 1;
FIG. 5 is a stress-strain curve of TRIP steels of example 1 and comparative examples 1 to 2 of the present invention. Wherein the abscissa Engineering Strain is Engineering Strain, and the ordinate Engineering Strain is Engineering Stress (MPa).
FIG. 6 is a stress-strain curve of TRIP steels of comparative examples 3 to 4 of example 1 of the present invention. Wherein the abscissa Engineering Strain is Engineering Strain, and the ordinate Engineering Strain is Engineering Stress (MPa);
FIG. 7 is a SEM image of a tensile fracture of the TRIP steel of example 1 of the present invention;
FIG. 8 is an SEM image of tensile fracture of the TRIP steel of example 1.
Detailed Description
The technical solution of the present invention will be described in detail by specific examples.
Example 1
The steel comprises the following chemical components in percentage by mass: c: 0.22%, Mn: 11.47%, Al: 1.95%, S: 0.005%, P: 0.007% and the balance of Fe and inevitable impurities.
The preparation method of the TRIP steel with the ultrahigh product of strength and elongation of strength provided by the embodiment comprises the following steps:
(1) adding the steel into a vacuum induction furnace according to the chemical components of the steel, and heating the smelting furnace to 1550-1650 ℃. And then casting the smelted molten steel into an ingot.
(2) And (3) keeping the temperature of the cast ingot at 1200 ℃ for 2 hours to homogenize the structure, forging the cast ingot into a plate blank with the thickness of 18-22 mm, and then cooling in air.
(3) And (3) carrying out structure homogenization treatment on the air-cooled plate blank at 1150 ℃ for 2 hours, then carrying out hot rolling treatment to obtain a hot rolled plate, wherein the hot rolling passes are 7-8 times, the thickness of the plate after rolling is 5mm, and cooling the plate to room temperature in an air cooling mode. The initial rolling temperature of hot rolling is 1150 ℃, and the final rolling temperature is 950 ℃.
(4) Heating the hot rolled plate to 600-650 ℃, preserving heat for 2 hours, carrying out warm rolling at 600-650 ℃, carrying out warm rolling for 3-4 times, wherein the thickness of the obtained warm rolled plate after warm rolling is 2mm, and carrying out air cooling to room temperature;
(5) and (3) annealing treatment in a two-phase region, heating the warm-rolled plate to 600 ℃, preserving heat for 40 minutes, and cooling in air to room temperature.
And (3) carrying out a tensile test on the obtained TRIP steel after polishing the oxide skin to obtain tensile strength, yield strength and elongation after fracture.
The tensile strength of the TRIP steel with the ultrahigh product of strength and elongation obtained by annealing treatment in the step (5) is 1366.0MPa, the elongation after fracture is 52.5%, and the product of strength and elongation is 71.7 GPa%.
Comparative example 1
The steel comprises the following chemical components in percentage by mass: c: 0.22%, Mn: 11.47%, Al: 1.95%, S: 0.005%, P: 0.007% and the balance of Fe and inevitable impurities.
The preparation method of the TRIP steel with the ultrahigh product of strength and elongation in the comparative example 1 comprises the following steps:
(1) adding the steel into a vacuum induction furnace according to the chemical components of the steel, and heating the smelting furnace to 1550-1650 ℃. And then casting the smelted molten steel into an ingot.
(2) And (3) keeping the temperature of the cast ingot at 1200 ℃ for 2 hours to homogenize the structure, forging the cast ingot into a plate blank with the thickness of 18-22 mm, and then cooling in air.
(3) And (3) carrying out structure homogenization treatment on the air-cooled plate blank at 1150 ℃ for 2 hours, then carrying out hot rolling treatment to obtain a hot rolled plate, wherein the hot rolling passes are 7-8 times, the thickness of the plate after rolling is 5mm, and cooling the plate to room temperature in an air cooling mode. The initial rolling temperature of hot rolling is 1150 ℃, and the final rolling temperature is 950 ℃.
(4) Heating the hot rolled plate to 600-650 ℃, preserving heat for 2 hours, carrying out warm rolling at 600-650 ℃, carrying out warm rolling for 3-4 times, wherein the thickness of the obtained warm rolled plate after warm rolling is 2mm, and carrying out air cooling to room temperature;
(5) and (3) annealing treatment in a two-phase region, heating the warm-rolled plate to 550 ℃, preserving heat for 40 minutes, and cooling in air to room temperature.
And (3) carrying out a tensile test on the obtained TRIP steel after polishing the oxide skin to obtain tensile strength, yield strength and elongation after fracture.
This comparative example is different from example 1 in that the temperature at the time of annealing treatment was 550 ℃, and the obtained TRIP steel had a tensile strength of 1243.4MPa, an elongation after fracture of 38.6%, and a product of strength and elongation of 48.0 GPa%.
Comparative example 2
The steel comprises the following chemical components in percentage by mass: c: 0.22%, Mn: 11.47%, Al: 1.95%, S: 0.005%, P: 0.007% and the balance of Fe and inevitable impurities.
The preparation method of the TRIP steel with the ultrahigh product of strength and elongation of the steel in the comparative example 2 comprises the following steps:
(1) adding the steel into a vacuum induction furnace according to the chemical components of the steel, and heating the smelting furnace to 1550-1650 ℃. And then casting the smelted molten steel into an ingot.
(2) And (3) keeping the temperature of the cast ingot at 1200 ℃ for 2 hours to homogenize the structure, forging the cast ingot into a plate blank with the thickness of 18-22 mm, and then cooling in air.
(3) And (3) carrying out structure homogenization treatment on the air-cooled plate blank at 1150 ℃ for 2 hours, then carrying out hot rolling treatment to obtain a hot rolled plate, wherein the hot rolling passes are 7-8 times, the thickness of the plate after rolling is 5mm, and cooling the plate to room temperature in an air cooling mode. The initial rolling temperature of hot rolling is 1150 ℃, and the final rolling temperature is 950 ℃.
(4) Heating the hot rolled plate to 600-650 ℃, preserving heat for 2 hours, carrying out warm rolling at 600-650 ℃, carrying out warm rolling for 3-4 times, wherein the thickness of the obtained warm rolled plate after warm rolling is 2mm, and carrying out air cooling to room temperature;
(5) and (3) annealing treatment in a two-phase region, heating the warm-rolled plate to 650 ℃, preserving heat for 40 minutes, and cooling in air to room temperature.
And (3) carrying out a tensile test on the obtained TRIP steel after polishing the oxide skin to obtain tensile strength, yield strength and elongation after fracture.
This comparative example is different from example 1 in that the temperature at the time of annealing treatment was 650 ℃, and the obtained TRIP steel had a tensile strength of 1042.2MPa, an elongation after fracture of 30.5%, and a product of strength and elongation of 31.8 GPa%.
Comparative example 3
The steel comprises the following chemical components in percentage by mass: c: 0.22%, Mn: 11.47%, Al: 1.95%, S: 0.005%, P: 0.007% and the balance of Fe and inevitable impurities.
The preparation method of the TRIP steel with the ultrahigh product of strength and elongation in comparison with the comparative example 3 comprises the following steps:
(1) adding the steel into a vacuum induction furnace according to the chemical components of the steel, and heating the smelting furnace to 1550-1650 ℃. And then casting the smelted molten steel into an ingot.
(2) And (3) keeping the temperature of the cast ingot at 1200 ℃ for 2 hours to homogenize the structure, forging the cast ingot into a plate blank with the thickness of 18-22 mm, and then cooling in air.
(3) And (3) carrying out structure homogenization treatment on the air-cooled plate blank at 1150 ℃ for 2 hours, then carrying out hot rolling treatment to obtain a hot rolled plate, wherein the hot rolling passes are 7-8 times, the thickness of the plate after rolling is 5mm, and cooling the plate to room temperature in an air cooling mode. The initial rolling temperature of hot rolling is 1150 ℃, and the final rolling temperature is 950 ℃.
(4) Heating the hot rolled plate to 600-650 ℃, preserving heat for 2 hours, carrying out warm rolling at 600-650 ℃, carrying out warm rolling for 3-4 times, wherein the thickness of the obtained warm rolled plate after warm rolling is 2mm, and carrying out air cooling to room temperature;
(5) and (3) annealing treatment in a two-phase region, heating the warm-rolled plate to 600 ℃, preserving heat for 20 minutes, and cooling in air to room temperature.
And (3) carrying out a tensile test on the obtained TRIP steel after polishing the oxide skin to obtain tensile strength, yield strength and elongation after fracture.
This comparative example is different from example 1 in that the annealing treatment time was 20 minutes, and the obtained TRIP steel had a tensile strength of 1311.0MPa, an elongation after fracture of 42.5%, and a product of strength and elongation of 55.7 GPa%.
Comparative example 4
The steel comprises the following chemical components in percentage by mass: c: 0.22%, Mn: 11.47%, Al: 1.95%, S: 0.005%, P: 0.007% and the balance of Fe and inevitable impurities.
The preparation method of the TRIP steel with the ultrahigh product of strength and elongation of the steel in the comparative example 4 comprises the following steps:
(1) adding the steel into a vacuum induction furnace according to the chemical components of the steel, and heating the smelting furnace to 1550-1650 ℃. And then casting the smelted molten steel into an ingot.
(2) And (3) keeping the temperature of the cast ingot at 1200 ℃ for 2 hours to homogenize the structure, forging the cast ingot into a plate blank with the thickness of 18-22 mm, and then cooling in air.
(3) And (3) carrying out structure homogenization treatment on the air-cooled plate blank at 1150 ℃ for 2 hours, then carrying out hot rolling treatment to obtain a hot rolled plate, wherein the hot rolling passes are 7-8 times, the thickness of the plate after rolling is 5mm, and cooling the plate to room temperature in an air cooling mode. The initial rolling temperature of hot rolling is 1150 ℃, and the final rolling temperature is 950 ℃.
(4) Heating the hot rolled plate to 600-650 ℃, preserving heat for 2 hours, carrying out warm rolling at 600-650 ℃, carrying out warm rolling for 3-4 times, wherein the thickness of the obtained warm rolled plate after warm rolling is 2mm, and carrying out air cooling to room temperature;
(5) and (3) annealing treatment in a two-phase region, heating the warm-rolled plate to 600 ℃, preserving heat for 5 hours, and cooling in air to room temperature.
And (3) carrying out a tensile test on the obtained TRIP steel after polishing the oxide skin to obtain tensile strength, yield strength and elongation after fracture.
This comparative example is different from example 1 in that the annealing treatment time was 5 hours, and the obtained TRIP steel had a tensile strength of 1212.8MPa, an elongation after fracture of 43.6%, and a product of strength and elongation of 52.8 GPa%.
In order to obtain the structure and percentage content of the TRIP steel, SEM photographs and XRD patterns before and after deformation of the TRIP steel of example 1 were prepared after the above-described specific operation steps.
The structures of example 1 and comparative examples 1 to 4 were analyzed to be austenite, ferrite and martensite, but the percentage contents of the structures were different depending on the heat treatment process parameters.
The performance parameters of example 1 and comparative examples 1 to 4 are shown in Table 1
TABLE 1 Performance parameter tables for example 1 and comparative examples 1-4
The mechanism of the TRIP steel with ultra-high product of strength and elongation is the TRIP effect, and as can be seen from the analysis of FIGS. 2 and 3, when the TRIP steel of example 1 is subjected to an external force, austenite in the steel is transformed into martensite to absorb energy to resist deformation. Fig. 4 shows that the austenite content of the TRIP steel with an ultra-high product of strength and elongation in example 1 is 73.2% before the tensile test and 35.7% after the tensile test, and the high austenite transformation ratio thereof enables the TRIP steel of the present invention to have the characteristic of a high product of strength and elongation, i.e., to absorb a large amount of energy when being subjected to an external force.
As a result of analyzing Table 1 and FIG. 5, the heat treatment temperature has a great influence on the properties of the steel. The difference between the process parameters of the example 1 and the comparative examples 1-2 is the difference between the heat treatment temperatures, and it can be seen from fig. 2 that the comprehensive mechanical properties of the TRIP steel obtained in the example 1 are obviously higher than those of the comparative examples 1-2, and when the annealing temperature is higher or lower than the heat treatment temperature required by the invention, the properties of the obtained material are all reduced.
Further analysis of Table 1 and FIG. 6 shows that the heat treatment time also has a great influence on the properties of the steel. The heat treatment time of comparative example 3 is shorter than that of example 1, and since the heat treatment time is short such that the internal stress generated during rolling cannot be sufficiently removed and the residual internal stress seriously affects the mechanical properties of the material, the tensile strength of comparative example 3 can be up to 1300MPa, but the elongation and the product of strength and elongation are lower than those of example 1.
While the heat treatment time of comparative example 4 is significantly higher than that of example 1, the excessively long heat treatment results in the growth of austenite grains and the decrease of ferrite phase and martensite phase, and the strength and plasticity of the material become small.
The results show that the TRIP steel prepared by the method has excellent comprehensive performance, the tensile strength is within 1300-1450 MPa, the elongation is 50-65%, and the product of strength and elongation can reach 70 GPa%, meets the performance requirements of the automobile industry on automobile steel, and has extremely high market application value.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention.
Claims (8)
1. The TRIP steel with the ultrahigh product of strength and elongation is characterized by comprising the following chemical components in percentage by mass: 0.16-0.28% of C, 8-12.5% of Mn, 1.5-3% of Al, 0-0.005% of S, 0-0.008% of P, and the balance of Fe and inevitable impurities.
2. The method for preparing the TRIP steel with ultra-high product of strength and elongation as claimed in claim 1, wherein the method comprises the following steps:
smelting: smelting according to the chemical components of the TRIP steel, and casting into an ingot;
forging: firstly, preserving heat for 2 +/-0.5 hours within the temperature range of 1150-1250 ℃ to homogenize the structure, then forging the cast ingot into a plate blank, and cooling in the air;
hot rolling: carrying out tissue homogenization treatment on the plate blank at the temperature of 1120-1180 ℃ for 2 +/-0.5 hours, then carrying out hot rolling to obtain a hot rolled plate, and cooling to room temperature in an air cooling mode;
warm rolling: carrying out second tissue homogenization treatment, heating the hot rolled plate to 600-650 ℃, preserving heat for 2 +/-0.5 hours, carrying out warm rolling at 600-650 ℃, and air-cooling to room temperature;
and (3) annealing the two-phase region: and (3) preserving the heat at the temperature of 575-625 ℃ for 40 min-1 h, and air-cooling to room temperature to obtain the TRIP steel with ultrahigh product of strength and elongation.
3. The method for preparing the TRIP steel with ultra-high product of strength and elongation as claimed in claim 2, wherein the smelting device in the smelting step is a vacuum induction furnace, and the smelting material is induced by an electromagnetic induction principle under a vacuum condition to achieve the purpose of heating, and the temperature in the furnace is 1550 ℃ to 1650 ℃.
4. The method for preparing the TRIP steel with ultra-high product of strength and elongation as claimed in claim 2, wherein in the forging step, the thickness of the forged slab is 18-22 mm.
5. The method for producing the TRIP steel having an ultra-high product of strength and elongation as claimed in claim 2, wherein in the hot rolling step, the thickness of the hot-rolled sheet after hot rolling is 5mm, and the number of hot rolling passes is 7 to 8.
6. The method for preparing the TRIP steel with ultra-high product of strength and elongation as claimed in claim 5, wherein the start rolling temperature is 1120-1180 ℃, and the finish rolling temperature is 900-950 ℃.
7. The method for preparing the TRIP steel with the ultrahigh product of strength and elongation as claimed in claim 2, wherein in the warm rolling step, the thickness of the obtained warm rolled plate after the warm rolling is 2mm, and the number of warm rolling passes is 3-4.
8. The method for preparing the TRIP steel with ultra-high product of strength and elongation as claimed in claim 2, wherein in the two-phase region annealing step, the heating rate in the heat treatment process is 2-8 ℃/s.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010018674.XA CN111218621A (en) | 2020-01-08 | 2020-01-08 | TRIP steel with ultrahigh strength-elongation product and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010018674.XA CN111218621A (en) | 2020-01-08 | 2020-01-08 | TRIP steel with ultrahigh strength-elongation product and preparation method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111218621A true CN111218621A (en) | 2020-06-02 |
Family
ID=70832249
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010018674.XA Pending CN111218621A (en) | 2020-01-08 | 2020-01-08 | TRIP steel with ultrahigh strength-elongation product and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111218621A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112251685A (en) * | 2020-09-29 | 2021-01-22 | 中国科学院金属研究所 | Ultrahigh-strength nanocrystalline 12Cr13Cu4Mo stainless steel and preparation method thereof |
| CN112410681A (en) * | 2020-11-26 | 2021-02-26 | 燕山大学 | High-strength-ductility medium manganese steel and preparation method thereof |
| WO2022018571A1 (en) * | 2020-07-24 | 2022-01-27 | Arcelormittal | Hot rolled and heat-treated steel sheet and method of manufacturing the same |
| CN114381671A (en) * | 2020-10-02 | 2022-04-22 | 香港大学 | High-strength and high-plasticity medium manganese steel and production method thereof |
| CN115323275A (en) * | 2022-09-05 | 2022-11-11 | 东北大学 | High-strength high-toughness rare earth warm-rolled low-carbon low-manganese TRIP steel and preparation method thereof |
| CN115537672A (en) * | 2022-07-19 | 2022-12-30 | 燕山大学 | Low-cost austenitic steel with yield strength of more than 1000MPa and warm rolling preparation process thereof |
| RU2802328C1 (en) * | 2020-07-24 | 2023-08-24 | Арселормиттал | Hot-rolled and heat treated steel sheet and method for its manufacture |
| CN116752048A (en) * | 2023-06-12 | 2023-09-15 | 北京科技大学 | Ultrahigh-strength and high-toughness medium-manganese steel with strength-plastic product of more than 90GPa% and preparation method thereof |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101058863A (en) * | 2007-06-11 | 2007-10-24 | 北京科技大学 | Hot-rolled low-silicon multiphase steel and preparation method thereof |
| CN103695765A (en) * | 2013-12-11 | 2014-04-02 | 蔡志辉 | Cold-rolled medium manganese steel with high strength and high plasticity and preparation method thereof |
| CN106086640A (en) * | 2016-06-21 | 2016-11-09 | 北京科技大学 | Cold rolling medium managese steel that a kind of superhigh intensity plasticity is long-pending and preparation method thereof |
| CN109554615A (en) * | 2018-12-29 | 2019-04-02 | 首钢集团有限公司 | A kind of tensile strength 900MPa grades of analysis of producing hot rolled TRIP and preparation method thereof |
| CN109868345A (en) * | 2019-02-27 | 2019-06-11 | 河北工程大学 | Manganese TRIP steel and preparation method thereof in a kind of high strength and ductility cold rolling with the multiple dimensioned austenite structure of multiform looks |
| CN110066964A (en) * | 2019-04-09 | 2019-07-30 | 东北大学 | A kind of superhigh intensity medium managese steel and its warm-rolling preparation method |
| CN110438315A (en) * | 2019-09-06 | 2019-11-12 | 安徽工业大学 | A kind of heat treatment method improving Fe-Mn-Al-C system TRIP steel mechanical property |
-
2020
- 2020-01-08 CN CN202010018674.XA patent/CN111218621A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101058863A (en) * | 2007-06-11 | 2007-10-24 | 北京科技大学 | Hot-rolled low-silicon multiphase steel and preparation method thereof |
| CN103695765A (en) * | 2013-12-11 | 2014-04-02 | 蔡志辉 | Cold-rolled medium manganese steel with high strength and high plasticity and preparation method thereof |
| CN106086640A (en) * | 2016-06-21 | 2016-11-09 | 北京科技大学 | Cold rolling medium managese steel that a kind of superhigh intensity plasticity is long-pending and preparation method thereof |
| CN109554615A (en) * | 2018-12-29 | 2019-04-02 | 首钢集团有限公司 | A kind of tensile strength 900MPa grades of analysis of producing hot rolled TRIP and preparation method thereof |
| CN109868345A (en) * | 2019-02-27 | 2019-06-11 | 河北工程大学 | Manganese TRIP steel and preparation method thereof in a kind of high strength and ductility cold rolling with the multiple dimensioned austenite structure of multiform looks |
| CN110066964A (en) * | 2019-04-09 | 2019-07-30 | 东北大学 | A kind of superhigh intensity medium managese steel and its warm-rolling preparation method |
| CN110438315A (en) * | 2019-09-06 | 2019-11-12 | 安徽工业大学 | A kind of heat treatment method improving Fe-Mn-Al-C system TRIP steel mechanical property |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022018571A1 (en) * | 2020-07-24 | 2022-01-27 | Arcelormittal | Hot rolled and heat-treated steel sheet and method of manufacturing the same |
| WO2022018504A1 (en) * | 2020-07-24 | 2022-01-27 | Arcelormittal | Hot rolled and heat-treated steel sheet and method of manufacturing the same |
| RU2802328C1 (en) * | 2020-07-24 | 2023-08-24 | Арселормиттал | Hot-rolled and heat treated steel sheet and method for its manufacture |
| CN112251685A (en) * | 2020-09-29 | 2021-01-22 | 中国科学院金属研究所 | Ultrahigh-strength nanocrystalline 12Cr13Cu4Mo stainless steel and preparation method thereof |
| CN114381671A (en) * | 2020-10-02 | 2022-04-22 | 香港大学 | High-strength and high-plasticity medium manganese steel and production method thereof |
| CN112410681A (en) * | 2020-11-26 | 2021-02-26 | 燕山大学 | High-strength-ductility medium manganese steel and preparation method thereof |
| CN115537672A (en) * | 2022-07-19 | 2022-12-30 | 燕山大学 | Low-cost austenitic steel with yield strength of more than 1000MPa and warm rolling preparation process thereof |
| CN115537672B (en) * | 2022-07-19 | 2023-08-18 | 燕山大学 | Low-cost austenitic steel with yield strength greater than 1000MPa and warm rolling preparation process thereof |
| CN115323275A (en) * | 2022-09-05 | 2022-11-11 | 东北大学 | High-strength high-toughness rare earth warm-rolled low-carbon low-manganese TRIP steel and preparation method thereof |
| CN116752048A (en) * | 2023-06-12 | 2023-09-15 | 北京科技大学 | Ultrahigh-strength and high-toughness medium-manganese steel with strength-plastic product of more than 90GPa% and preparation method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111218621A (en) | TRIP steel with ultrahigh strength-elongation product and preparation method thereof | |
| CN113106338B (en) | Preparation method of ultrahigh-strength high-plasticity hot stamping formed steel | |
| CN102828109A (en) | Metastable-state phase-change plastification ultra-fine grain high-intensity plastic product steel and production method thereof | |
| EP4198158A1 (en) | Steel board for polar marine engineering and preparation method therefor | |
| CN111041376B (en) | Preparation method of 2000 MPa-level ultrahigh-strength TRIP steel | |
| CN110846554B (en) | High-ductility EH 32-grade ocean engineering steel and manufacturing method of steel plate | |
| CN113249645B (en) | High-ductility and ultrahigh-strength ductile steel and preparation method thereof | |
| CN102400036A (en) | Twin induced plastic steel with high elongation percentage and high hole expansion rate and manufacture method thereof | |
| CN111074148A (en) | 800 MPa-level hot stamping axle housing steel and manufacturing method thereof | |
| JP2020509165A (en) | Extra-thick steel material excellent in surface portion NRL-DWT physical properties and method for producing the same | |
| CN110951946B (en) | Heat treatment process of low-density steel and preparation method thereof | |
| CN108728728B (en) | High manganese steel with extremely low yield ratio and manufacturing method thereof | |
| CN102650017A (en) | Hot-rolled steel plate and manufacturing method thereof | |
| JP2020509168A (en) | Surface part NRL-Extra-thick steel material excellent in physical properties for drop test and method for producing the same | |
| CN115522126B (en) | Medium manganese steel with good wear resistance and production method thereof | |
| CN114875318B (en) | Dispersed delta phase strengthened low-density high-strength and high-toughness steel and manufacturing method thereof | |
| JP2008013812A (en) | High toughness and high tensile strength thick steel plate and its production method | |
| CN114807772B (en) | Aging-strengthened high-strength high-toughness light steel and manufacturing method thereof | |
| CN110331344A (en) | A kind of Rm >=600MPa beam steel that strength character is stable and production method | |
| JP3280692B2 (en) | Manufacturing method of high strength cold rolled steel sheet for deep drawing | |
| CN110592484B (en) | 460 MPa-level low-welding-crack-sensitivity refractory steel with excellent low-temperature toughness and production method thereof | |
| JP2002363685A (en) | Low yield ratio high strength cold rolled steel sheet | |
| CN113897548A (en) | Low-temperature-resistant easily-welded ultra-low-carbon steel thick plate and preparation method thereof | |
| CN115323275B (en) | High-strength high-toughness rare earth warm-rolled low-carbon low-manganese TRIP steel and preparation method thereof | |
| CN115491614B (en) | Austenitic high manganese steel with strength-plastic product larger than 60 GPa% |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20200602 |
|
| RJ01 | Rejection of invention patent application after publication |