CN113322414A - High-plasticity steel and preparation method thereof - Google Patents
High-plasticity steel and preparation method thereof Download PDFInfo
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- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
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- C21D2211/001—Austenite
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- C21D2211/00—Microstructure comprising significant phases
- C21D2211/002—Bainite
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- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
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- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
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Abstract
The invention discloses high-plasticity steel and a preparation method thereof, belongs to the technical field of metal materials, and solves the problems of poor strong plasticity matching property or high manufacturing cost of high-strength steel in the prior art. The high-plasticity steel comprises the following components in percentage by mass: c: 0.02% -0.095%, Si: 0.2% -1.0%, Mn: 2.5% -6.0%, P: < 0.02%, S: < 0.01%, the balance being Fe and unavoidable impurities. The preparation method comprises the following steps: smelting and pouring to obtain a casting blank or an ingot; carrying out high-temperature homogenization treatment on a casting blank or a cast ingot, and then forging and cogging; hot rolling the forged blank; adopting an air cooling or accelerated cooling method for the hot-rolled steel pipe to obtain granular bainite or martensite + bainite tissues; and heating the hot-rolled steel pipe to the temperature between the two phase regions, preserving the heat for 1-10 hours, and then cooling to room temperature to obtain the high-plasticity steel plate or steel strip. The high-plasticity steel disclosed by the invention is excellent in mechanical property and low in cost.
Description
Technical Field
The invention belongs to the technical field of metal materials, and particularly relates to high-plasticity steel and a preparation method thereof.
Background
Steel materials always occupy the dominant position in structural materials, and at present, no material can comprehensively replace the steel materials. With the development of society and economy, the steel industry is under three major pressures of saving resources, saving energy and protecting the environment. Improving the quality of steel, reducing the cost and greatly improving the comprehensive mechanical property of the steel become the main direction of the research of steel materials.
The advanced high-strength steel is widely applied to industries such as automobiles, buildings, bridges, ocean platforms, oil and gas pipelines, ship manufacturing and the like. Compared with common high-strength steel, the high-strength steel has the greatest advantages that the thickness and the weight of a plate member are reduced while the mechanical property is ensured, and in addition, the advanced high-strength steel also has the advantages of good formability, anti-collision concavity, high fracture toughness and the like, and shows good application prospects in various industries. At present, under the common efforts of many researchers of steel materials at home and abroad, the first generation advanced high strength steel represented by interstitial free steel, DP, TRIP, complex phase steel, martensite steel and the like, and the second generation advanced high strength steel represented by TWIP steel have been developed. Among these steels, TRIP steels having excellent plasticity are prepared by means of a hot rolling or critical zone isothermal quenching process, and a three-phase structure of a large amount of stable austenite is obtained by diffusion of carbon atoms into austenite at the time of bainite transformation. TWIP steels rely on high alloying elements (Mn mass fraction greater than 18%) to increase austenite stability to obtain twinning induced plasticity. The method for obtaining high plasticity has complex components, high requirements on equipment for the process and high cost and is difficult to popularize.
In recent years, the developed third-generation advanced high-strength steel has better strength and toughness than the first-generation advanced high-strength steel, and simultaneously, the cost of the steel is obviously reduced compared with the second-generation high-strength steel. The main alloy elements of the third generation advanced high-strength steel are carbon and manganese, and both have the functions of enlarging an austenite phase region and stabilizing residual austenite. However, the third generation advanced high-strength steel with high plasticity generally has the strength level of about 1000MPa, and does not have toughness. For example, a high-strength high-plasticity hot-rolled steel sheet of 1000MPa class, which is studied at northeast university, and a method for manufacturing the same (CN105925896A), have a tensile strength of 1000MPa or more, but the steel sheet has not satisfactory impact toughness, and at present, studies on high-strength steel having a tensile strength in the range of 300 to 700MPa and having high ductility and high toughness at low cost have been very rare.
Disclosure of Invention
In view of the above analysis, the present invention aims to provide a high plasticity steel and a method for producing the same, which can solve at least one of the following technical problems: (1) in the prior art, high-strength steel has high tensile strength, but has poor plasticity and poor strong plasticity matching property; (2) high manufacturing cost, long heat treatment process time, complex process and the like of the high-strength high-plasticity steel. The invention aims to obtain low-cost high-plasticity steel (such as a steel plate or a steel strip) through reasonable component design, and combine a reasonable preparation method to enable the steel (such as the steel plate or the steel strip) to reach the expected strength and plasticity level, thereby ensuring the use requirement of the steel.
The purpose of the invention is mainly realized by the following technical scheme:
in one aspect, the present invention provides a high plasticity steel, the composition of which is, in mass percent: c: 0.02% -0.095%, Si: 0.2% -1.0%, Mn: 2.5% -6.0%, P: < 0.02%, S: < 0.01%, the balance being Fe and unavoidable impurities.
Further, the high-plasticity steel comprises the following components in percentage by mass: c: 0.03% -0.09%, Si: 0.27% -0.4%, Mn: 2.6% -5.8%, P: < 0.01%, S: < 0.005%, and the balance Fe and inevitable impurities.
Furthermore, the microstructure of the high-plasticity steel is tempered martensite and/or tempered bainite + ferrite + residual austenite, wherein the volume percentage of ferrite is less than 5%, and the volume percentage of residual austenite is more than 5%.
Further, the volume percentage of the retained austenite is 5-20%.
Furthermore, the yield strength of the high-plasticity steel is more than 450MPa, the tensile strength is more than 670MPa, the elongation after fracture is more than 35%, the uniform elongation is more than 20%, and the impact energy at minus 10 ℃ is more than or equal to 200J.
Further, the high-plasticity steel also comprises one or more of Mo, Cr, Ni, V, Nb, V and Ti elements.
On the other hand, the invention also provides a preparation method of the high-plasticity steel, which comprises the following steps:
step 1, smelting and pouring to obtain a casting blank or an ingot;
step 2, performing high-temperature homogenization treatment on the casting blank or the cast ingot, and then forging and cogging;
step 3, hot rolling the forged blank;
and 4, controlling cooling: adopting an air cooling or accelerated cooling method for the hot-rolled steel pipe to obtain granular bainite or martensite + bainite tissues;
step 5, annealing of the two-phase region: and heating the hot-rolled steel pipe to the temperature between the two phase regions, preserving the heat for 1-10 hours, and then cooling to room temperature to obtain the high-plasticity steel plate or steel strip.
Further, in step 2, the high-temperature homogenization treatment includes: heating the casting blank or the ingot to 1100-1250 ℃, and preserving heat for 2-5 h.
Further, in the step 3, the hot rolling process includes: heating the casting blank to 1100-1250 ℃, preserving heat for more than 2 hours, starting rolling at 1050-1100 ℃, and further putting the hot rolled steel pipe into a heating furnace at room temperature in the step 5.
Further, in the step 5, the temperature between the two phase regions is 10-50 ℃ above Ac 1.
Compared with the prior art, the invention can at least realize one of the following technical effects:
1) according to the invention, by accurately controlling the mass percentages of C, Si and Mn elements in the steel, adopting the low-carbon medium-manganese component design and combining the two-phase zone annealing process, the steel obtains a multi-phase structure of tempered martensite (or tempered bainite) + ferrite + residual austenite, and the steel plate or steel strip is ensured to have higher strength level and simultaneously have higher plastic deformation capability and high toughness level. Ensuring that the steel of the invention can meet excellent mechanical properties. The invention can form a low-cost solution without adding Mo, Cr or V alloy elements.
2) The invention obtains a multiphase structure of 'tempered martensite and/or tempered bainite + ferrite + residual austenite' by controlling the rolling and cooling and then carrying out a two-phase region annealing process, wherein the volume percentage of the ferrite is below 5 percent, and the volume percentage of the residual austenite is between 5 and 20 percent, thereby obtaining the ideal matching of strength, toughness and yield ratio; the strength and toughness of the steel of the present composition can be matched only by heat treatment within the steps and temperature ranges of the present invention, all to the required range.
3) The high-plasticity steel prepared by the components and the method has good comprehensive mechanical property, the yield strength is more than 450MPa, the tensile strength is more than 670MPa, the elongation after fracture is more than 35 percent, the uniform elongation is more than 20 percent, and the impact toughness at minus 10 ℃ is more than or equal to 200J. Can meet the performance requirements of high-ductility and high-toughness steel plates in the strength range, and simultaneously, the component system also greatly reduces the alloy cost.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objectives and other advantages of the invention may be realized and attained by the instrumentalities and combinations particularly pointed out in the written description.
Detailed Description
A high plasticity steel and a method for manufacturing the same will be described in further detail with reference to specific examples, which are provided for purposes of comparison and explanation only, and the present invention is not limited to these examples.
High-plasticity steel, which comprises the following components in percentage by mass: c: 0.02% -0.095%, Si: 0.2% -1.0%, Mn: 2.5% -6.0%, P: < 0.02%, S: < 0.01%, the balance being Fe and unavoidable impurities.
The function and amount of the components contained in the present invention are specifically described below:
c: carbon in steel has an important influence on the carbon content and volume fraction of the finally reversed austenite and martensite. Only if sufficient carbon is guaranteed will sufficient carbon-rich retained austenite be formed and able to stabilize to room temperature. In a certain two-phase region, the carbon content is increased, the concentration of carbon in austenite is increased, the stability of austenite is enhanced, more austenite is stably kept to room temperature, and the volume fraction of reversed austenite is improved. However, when the carbon content is high, the weldability deteriorates. Therefore, a reasonable carbon content should be chosen to avoid Fe while ensuring sufficient retained austenite3C forms brittleness and improves welding performance. Therefore, the content of C in the invention is controlled to be 0.02-0.095%.
Mn: the addition of manganese can reduce the martensite transformation temperature Ms and increase the content of the retained austenite, and particularly when the steel contains 2-6% of manganese, the resistance to the decomposition of the retained austenite can be effectively improved. However, if the content of Mn is too high, the stability of the retained austenite is greatly improved, so that the retained austenite does not generate phase transformation when high plastic deformation exists, and the ductility of the workpiece is not improved; meanwhile, the content of Mn is too high, so that the carbon equivalent of the material is improved, and the welding performance is not favorable. The content of Mn in the invention is controlled to be 2.5-6.0%.
Si: silicon, which is not normally added as an alloying element, is a deoxidizer and, when Si exists in solid solution in austenite,can improve the strength and hardness of the steel, and has stronger action than Mn, Ni, Cr, V, Mo and the like. Si is a non-carbide-forming element, has extremely low solubility in carbide, and is Q&In the isothermal process of P steel, Fe can be strongly inhibited3The formation of C, which causes further carbon accumulation in the non-transformed austenite, promotes the martensite start temperature MS to fall below room temperature, favoring the formation of carbon-rich retained austenite. The content of Si in the invention is controlled to be 0.2-1.0%.
Aluminum is a non-carbide-forming element like silicon, and strongly suppresses the formation of Fe3C, thereby enriching the non-transformed austenite with carbon. Although aluminum has a weaker solid-solution strengthening effect than silicon, in Q & P steel, an aluminum element may be added to reduce the side effects of silicon. In addition, the coating and welding process of the steel is not affected by adopting aluminum instead of silicon, so that the aluminum is commonly used for replacing the silicon in the steel requiring coating and welding.
S: sulfur is a harmful element in steel in general, and steel having high sulfur content is easily brittle at high temperature press working, generally called hot shortness, and reduces ductility and toughness of steel, and is easily cracked at forging and rolling, and sulfur reduces corrosion resistance of steel, and deteriorates weldability of steel. The S content is controlled to be less than 0.01 percent in the invention.
P: in general, phosphorus is a harmful alloy element in steel, and when the content of phosphorus in steel exceeds a certain value, phosphorus precipitates at grain boundaries to destroy the strength of the grain boundaries and damage the ductility of the steel, so that the plasticity and the toughness of the steel are obviously reduced. The content of P in the invention is controlled to be less than 0.02 percent.
In order to further improve the comprehensive performance of the high-plasticity steel, the composition of the high-plasticity steel can be as follows by mass percent: c: 0.03% -0.09%, Si: 0.27% -0.4%, Mn: 2.6% -5.8%, P: < 0.01%, S: < 0.005%, and the balance Fe and inevitable impurities.
A method for producing a high-plasticity steel (steel plate/strip), comprising:
step 1, smelting and pouring to obtain a casting blank or an ingot;
step 2, performing high-temperature homogenization treatment on the casting blank or the cast ingot, and then forging and cogging;
step 3, hot rolling the forged blank: heating the casting blank to 1100-1250 ℃, preserving heat for more than 2 hours, and carrying out initial rolling at 1050-1100 ℃ and finishing rolling at 800-1000 ℃;
and 4, controlling cooling: adopting an air cooling or accelerated cooling method for the hot-rolled steel pipe to obtain granular bainite or martensite + bainite tissues;
step 5, annealing of the two-phase region: the hot-rolled steel pipe is heated to the temperature T1 (for example, 10-50 ℃ above Ac 1) between two phase regions, is kept warm for 1-10 h, and is cooled to room temperature, so that the high-plasticity steel plate/strip is obtained.
Specifically, in the step 1, a converter, an electric furnace or an induction furnace can be adopted for smelting, and continuous casting or die casting can be adopted for producing a casting blank or a casting ingot.
Specifically, in step 2, the high-temperature homogenization treatment specifically includes: heating the casting blank or the ingot to 1100-1250 ℃, and preserving heat for 2-5 h.
Specifically, in the step 4, granular bainite can be obtained by air cooling. The accelerated cooling can be water cooling, and a martensite + bainite structure is finally obtained after the water cooling.
Specifically, in the step 5, considering that the high-temperature charging affects the C diffusion to cause the performance change, the hot-rolled steel pipe is put into the resistance heating furnace at room temperature, and the heating speed is controlled to be 4-7 ℃/s.
Specifically, in the step 5, the heat preservation time is too long, and the cost is high; too short heat preservation time and too poor toughness. Therefore, the heat preservation time is controlled to be 1-10 h.
Specifically, in the step 5, the cooling manner may be furnace cooling or air cooling to room temperature according to specific requirements of performance.
In the step 5, the annealing heat preservation temperature is controlled between the two phase regions and is preserved for a period of time, the heat preservation time is longer, and the distribution is sufficient, so that the carbon-rich amount and the manganese amount in austenitizing are higher; in the subsequent furnace cooling or air cooling process, the stability of austenite is higher, which is beneficial to obtaining more residual austenite in steel at normal temperature. Thereby obtaining the ideal matching of the obdurability and the yield ratio.
In step 5, the microstructure of the high-plasticity steel plate/strip obtained is a multi-phase structure of tempered martensite and/or tempered bainite + ferrite + retained austenite, wherein the volume percentage of ferrite is less than 5%, and the volume percentage of retained austenite is 5% to 20%. It should be noted that tempered martensite or tempered bainite obtained in the microstructure is directly related to the components, tempered martensite is obtained with a high Mn content, and tempered bainite is mainly obtained with a low Mn content. In addition to some granular and acicular retained austenite present between ferrite and martensite in the microstructure of the high plasticity steel sheet/strip, some granular retained austenite is present at the prior austenite grain boundaries and inside the ferrite grains. The structure can greatly improve the plasticity and toughness of the steel plate.
Through the process, the high-plasticity steel plate/belt prepared by the invention has higher plasticity and excellent comprehensive performance than the conventional quenched and tempered steel due to the existence of soft-phase ferrite and the deformation induced phase transformation plasticity (Trip) effect generated by the retained austenite in the phase transformation process. The yield strength is more than 450MPa, the tensile strength is more than 670MPa, the elongation after fracture is more than 35 percent, the uniform elongation is more than 20 percent, and the impact energy at minus 10 ℃ is more than or equal to 200J. The high-plasticity steel plate/belt prepared by the components and the method of the high-plasticity steel plate/belt has the advantages of low cost, economy, practicability and good toughness.
Specifically, the invention is mainly suitable for low-alloy C, Mn steel, and can properly adjust chemical components (adding a small amount of other elements for microalloying treatment) and heating temperature, heat preservation time and the like of a two-phase region according to specific strong plasticity requirements to obtain the optimal multiphase structure ratio and meet different service performance requirements. For example, other Mo, Cr, Ni, V, Nb, V and Ti alloy elements are selectively added in small amount.
In a possible solution, one or several other elements may also be added: ni: 0.1-0.6%, Cr: 0.1-0.6%, Cu: 0.1% -0.5%, Nb: 0.01% -0.1%, V: 0.01 to 0.1 percent of Ti: 0.01 to 0.02 percent. Because the content of the added elements is very low, the cost is still lower compared with the existing steel with a large amount of added alloy elements.
Examples 1 to 3
Examples 1 to 3 of the present invention provide a high plasticity steel (steel plate/strip) and a method for preparing the same, the compositions of the steel of examples 1 to 3 are shown in table 1 below, and the mechanical properties of the steel are shown in table 3 below. The preparation method of the steels of examples 1 to 3 includes:
(1) smelting of steel
The steel of the invention was smelted in a laboratory vacuum induction furnace, the cast ingot form was a 100 kg round ingot, and the chemical composition of examples 1-3 is shown in Table 1.
TABLE 1 chemical composition (wt%) of steels of examples 1-3
| Serial number | C | Si | Mn | P | S | Als |
| Example 1 | 0.03 | 0.28 | 5.80 | 0.005 | 0.0019 | 0.023 |
| Example 2 | 0.06 | 0.27 | 3.56 | 0.005 | 0.0025 | 0.025 |
| Example 3 | 0.09 | 0.27 | 2.60 | 0.005 | 0.0022 | 0.027 |
(2) Forging and hot rolling of steel
Heating the steel of the embodiment 1-3 at 1100-1250 ℃, preserving heat for 2-5h, and forging and cogging; the forging temperature range is 800-1150 ℃, and air cooling is carried out after forging. Finally, the blank is forged into a size of 40mm by 80mm by 100 mm. Heating the forged blank at 1100-1250 ℃, preserving heat for 2-5h, and then carrying out hot rolling, wherein the initial rolling temperature of the blank is 1050-1100 ℃, the final rolling temperature is 800-900 ℃ after 7 passes of rolling by an experimental hot rolling mill, and the steel plate is air-cooled or directly water-quenched to room temperature after rolling.
Specifically, the process parameters of forging and hot rolling of examples 1 to 3 are shown in Table 2 below.
TABLE 2 Process parameters for the steels of examples 1-3
(3) Two phase zone annealing
Putting the steel plate into a resistance heating furnace, heating to 650 ℃ at the heating speed of 5 ℃/S, preserving heat for 10h, and cooling to room temperature along with the furnace.
(4) Mechanical properties
The mechanical properties of the steel sheets of examples 1 to 3 were tested and shown in Table 3. It has excellent mechanical properties.
TABLE 3 mechanical Properties of the Steel sheets of examples 1-3
Examples 4 to 6
Examples 4 to 6 of the present invention provide a high plasticity steel (steel plate/strip) and a method for preparing the same, the composition of the steel of examples 4 to 6 is shown in table 4 below, and the mechanical properties of the steel are shown in table 6 below. The preparation method of the steels of examples 4 to 6 includes:
(1) smelting of steel
The steel of the invention was smelted in a laboratory vacuum induction furnace, the detailed chemical composition of which is shown in table 4.
TABLE 4 chemical composition (wt%) of steels of examples 4-6
| Serial number | C | Si | Mn | P | S | Als |
| Examples 4 to 6 | 0.03 | 0.28 | 5.80 | 0.005 | 0.0019 | 0.023 |
(2) Forging and hot rolling of steel
The steel of the embodiment is heated to 1100-1250 ℃, and is subjected to heat preservation for 2-5 hours to be forged and cogging. The forging temperature is 800-1150 ℃, and air cooling is carried out after forging. Finally, the blank is forged into a size of 40mm by 80mm by 100 mm. Heating the forged blank by 1100-1250, keeping the temperature for 2-5h, then rolling the blank at 1050-1100 ℃ by 7 passes through an experimental hot rolling mill, rolling the blank at 800-900 ℃ and then air-cooling or directly water-quenching the rolled steel plate to room temperature.
Specifically, the process parameters for forging and hot rolling of examples 4-6 are shown in Table 5 below.
TABLE 5 Process parameters for the steels of examples 4-6
(3) Two phase zone annealing
The steel plate is put into a resistance heating furnace, heated to 610 ℃, 630 ℃ and 650 ℃ respectively at the heating speed of 5 ℃/S, and then cooled to room temperature along with the furnace after being respectively kept warm for different times. The detailed heat treatment process is shown in Table 6.
TABLE 6 annealing Process parameters for the steels of examples 4-6
| Serial number | Heating temperature/. degree.C | Holding time/h |
| Example 4 | 610 | 8 |
| Example 5 | 630 | 8 |
| Example 6 | 650 | 8 |
(4) Mechanical properties
The mechanical properties of examples 4-6 are shown in Table 7. Has the advantages of good plasticity and toughness and excellent mechanical property index
TABLE 7 mechanical Properties of the steels of examples 4-6
Specifically, the microstructures of examples 1 to 6 are multi-phase structures of tempered martensite and/or tempered bainite + ferrite + retained austenite ", in which the volume percentage of ferrite is 5% or less and the volume percentage of retained austenite is 5% to 20%. In conclusion, the steel has good comprehensive mechanical properties, the yield strength is greater than 450MPa (for example, 453-486 MPa), the tensile strength is greater than 670MPa (for example, 680-735 MPa), the elongation after fracture is more than 35%, the uniform elongation is more than 20% (for example, 20.5-29.5%), and the impact toughness at-10 ℃ is more than or equal to 200J (for example, 215-245J). Can meet the performance requirements of high-ductility and high-toughness steel plates in the strength range, and simultaneously, the component system also greatly reduces the alloy cost.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.
Claims (10)
1. High-plasticity steel, characterized in that the composition of the high-plasticity steel is, in mass percent: c: 0.02% -0.095%, Si: 0.2% -1.0%, Mn: 2.5% -6.0%, P: < 0.02%, S: < 0.01%, the balance being Fe and unavoidable impurities.
2. High-plasticity steel according to claim 1, characterized in that the composition of the high-plasticity steel is, in mass percent: c: 0.03% -0.09%, Si: 0.27% -0.4%, Mn: 2.6% -5.8%, P: < 0.01%, S: < 0.005%, and the balance Fe and inevitable impurities.
3. The high-plasticity steel according to claim 1, wherein the microstructure of the high-plasticity steel is tempered martensite and/or tempered bainite + ferrite + retained austenite, wherein the volume percentage of ferrite is 5% or less, and the volume percentage of retained austenite is 5% or more.
4. High plasticity steel according to claim 3, characterized in that the percentage by volume of retained austenite is between 5% and 20%.
5. The high-plasticity steel according to claim 1, wherein the yield strength of the high-plasticity steel is greater than 450MPa, the tensile strength is greater than 670MPa, the elongation after fracture is more than 35%, the uniform elongation is more than 20%, and the impact energy at-10 ℃ is more than or equal to 200J.
6. The high-plasticity steel according to claims 1 to 5, wherein the high-plasticity steel further comprises one or more of the elements Mo, Cr, Ni, V, Nb, V and Ti.
7. A method for producing high-plasticity steel is characterized by comprising the following steps:
step 1, smelting and pouring to obtain a casting blank or an ingot;
step 2, performing high-temperature homogenization treatment on the casting blank or the cast ingot, and then forging and cogging;
step 3, hot rolling the forged blank;
and 4, controlling cooling: adopting an air cooling or accelerated cooling method for the hot-rolled steel pipe to obtain granular bainite or martensite + bainite tissues;
step 5, annealing of the two-phase region: and heating the hot-rolled steel pipe to the temperature between the two phase regions, preserving the heat for 1-10 hours, and then cooling to room temperature to obtain the high-plasticity steel plate or steel strip.
8. The method for producing high-plasticity steel according to claim 7, wherein in the step 2, the step of high-temperature homogenization treatment is: heating the casting blank or the ingot to 1100-1250 ℃, and preserving heat for 2-5 h.
9. The method for producing high plasticity steel according to claim 7, wherein, in step 5, the hot-rolled steel pipe is placed in a heating furnace at room temperature.
10. A method for producing high plasticity steel according to any one of claims 7 to 9, wherein in step 5, the temperature between the two phase regions is 10 ℃ to 50 ℃ above Ac 1.
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| CN103160730A (en) * | 2013-03-20 | 2013-06-19 | 钢铁研究总院 | Large-swelling-amount welded tube and manufacturing method thereof |
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| CN103160730A (en) * | 2013-03-20 | 2013-06-19 | 钢铁研究总院 | Large-swelling-amount welded tube and manufacturing method thereof |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115341130A (en) * | 2022-09-06 | 2022-11-15 | 广西科技大学 | Method for preparing high-strength-ductility hot-rolled cold-formed automobile structural steel |
| CN115341130B (en) * | 2022-09-06 | 2023-08-11 | 广西科技大学 | Method for preparing high-strength plastic product hot-rolled cold-formed automobile structural steel |
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