CN111647818B - Ultra-fine grain size thin-specification high-manganese high-aluminum steel and production method thereof - Google Patents

Ultra-fine grain size thin-specification high-manganese high-aluminum steel and production method thereof Download PDF

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CN111647818B
CN111647818B CN202010626267.7A CN202010626267A CN111647818B CN 111647818 B CN111647818 B CN 111647818B CN 202010626267 A CN202010626267 A CN 202010626267A CN 111647818 B CN111647818 B CN 111647818B
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temperature
steel
manganese
cooling
heating
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CN111647818A (en
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甘晓龙
万响亮
徐光�
赵刚
杨庚蔚
刘升
肖欢
许耀文
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Wuhan University of Science and Engineering WUSE
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/04Ferrous alloys, e.g. steel alloys containing manganese
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D1/00General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26Methods of annealing
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226Hot rolling
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0236Cold rolling
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/001Ferrous alloys, e.g. steel alloys containing N
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/002Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/02Ferrous alloys, e.g. steel alloys containing silicon
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/06Ferrous alloys, e.g. steel alloys containing aluminium
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/12Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D2211/00Microstructure comprising significant phases
    • C21D2211/001Austenite
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D2211/00Microstructure comprising significant phases
    • C21D2211/008Martensite

Abstract

A high manganese high aluminum steel with ultra-fine grain size and thin specification comprises the following components in percentage by weight: c: 0.91-1.35%, Si: 0.21 to 0.53%, Mn: 8.5-16.2%, Al: 13.7-22.4%, Nb: 0.11-0.23%, V: 0.15-0.32%, P: less than or equal to 0.018%, S: less than or equal to 0.008 percent, N: less than or equal to 0.008 percent; the production method comprises the following steps: smelting and continuously casting into a blank; heating and descaling a casting blank; fine rolling; laminar cooling; coiling; naturally cooling to room temperature; cold rolling; and (5) continuously annealing. According to the invention, through reasonable component and process control and combination of Nb microalloying technology, the structure of the high-manganese high-aluminum steel is fully refined, and meanwhile, under the combined action of strengthening modes such as precipitation strengthening of Nb and V microalloy, the yield strength of the high-manganese high-aluminum steel is 1653-1721 MPa, the tensile strength is 2035-2119 MPa, the elongation is 52-62%, and the thickness is thinner; the annealing process is simpler and the annealing time is shorter.

Description

Ultra-fine grain size thin-specification high-manganese high-aluminum steel and production method thereof
Technical Field
The invention belongs to high-strength steel for automobiles and a production method thereof, and particularly relates to thin high-manganese high-aluminum steel with ultra-fine grain size and a production method thereof.
Background
In recent years, with the continuous high-speed development of the automobile industry in China, the automobile yield and the automobile retention capacity are continuously increased, and the method plays a positive promoting role in promoting the development of national economy. However, automotive energy consumption also has a tremendous impact and pressure on the energy conditions of the growing shortage and deteriorating environmental conditions. When energy conservation and emission reduction are unprecedentedly regarded as important, the automobile industry as a household with large energy consumption is undoubtedly more concerned. How to reduce the energy consumption of the automobile, the measures such as small displacement, new energy automobile development and the like are taken, the automobile weight is effectively reduced, and the realization of the light weight of the automobile is also one of important measures for energy conservation and emission reduction.
The lightweight automobile reduces the preparation quality of the automobile as much as possible on the premise of ensuring the strength and the safety performance of the automobile, thereby improving the dynamic property of the automobile, reducing the fuel consumption and reducing the exhaust pollution. The high-manganese high-aluminum steel has good plasticity and lower density, is an ideal automobile lightweight material, and is an effective means for realizing automobile lightweight by replacing the traditional automobile steel with the high-manganese high-aluminum steel. However, the main problem in the current production of high-manganese high-aluminum steel is that although the high-manganese high-aluminum steel has excellent plasticity, the strength of the high-manganese high-aluminum steel is low, and the application of the high-manganese high-aluminum steel is greatly limited. As retrieved:
the Chinese patent application No. 201710146561.6 discloses a vacuum melting method for Nb, V and Ti microalloyed high manganese high aluminum steel. The patent discloses a vacuum melting method of Nb, V and Ti microalloyed high manganese high aluminum steel. The high-manganese high-aluminum steel comprises the following chemical components in percentage by mass: c: 0.8 to 1.0%, Mn: 28-30% of Al: 8.0-10%, Nb: 0.02-0.10%, V: 0.02 to 0.10%, Ti: 0.02-0.10%, P < 0.003%, S < 0.003%, and the balance of Fe and unavoidable impurities. The method mainly solves the problem that the aluminum content is easy to burn and is difficult to control in the smelting process in the prior art, can accurately control the content of manganese, aluminum and titanium added in the smelting process, ensures that the content of manganese, aluminum and titanium in the Nb, V and Ti microalloyed high-manganese high-aluminum steel which is smelted meets the requirement, can ensure that alloy elements in the molten steel which is smelted are uniformly distributed, and ensures the quality of the molten steel. The patent mainly describes the smelting process of the high-manganese high-aluminum steel with the components, does not relate to the subsequent rolling heat treatment process, and from the strength range described by the smelting process, the steel has lower strength, the tensile strength is 1080-1230 MPa, and the product of strength and elongation is 48.6-56.6 GPa. From the production description process of the steel, the relevant experiment carried out in a laboratory does not have the condition of scale production.
Further, as disclosed in Chinese patent application No. 201711376945.3, "a high-strength high-plasticity low-density steel and a method for producing the same". The high-manganese high-aluminum steel low-density steel is smelted by adopting a vacuum induction furnace, and the steel comprises the following chemical components in percentage by mass: 1.0-1.6 wt% of C, 25-28 wt% of Mn, 2-8 wt% of Al and the balance of Fe. The steel ingot is subjected to high-temperature homogenization treatment at 1160-1200 ℃, the diffusion time is not more than 40 hours after 8 hours, the charging temperature is not more than 300 ℃, the steel ingot is forged into a round rod with the diameter of 16mm after the homogenization treatment, a standard tensile sample is taken, the steel ingot is subjected to solution treatment at 700-1200 ℃ for 1-3 hours, then oil quenching and cooling are carried out, and then the steel ingot is subjected to aging treatment at 300-550 ℃ for 5-10 hours. The tensile strength of the high-manganese high-aluminum steel is 1310MPa, and the elongation is 37%. From the above description, it can be found that annealing treatment for 4-13 hours is still required after forging and forming, so that annealing time consumption is long, the production process is complex, and the production process needs to be further improved. In addition, the steel is also relevant experiments carried out under laboratory conditions from the description of the patent, the condition of scale production is not provided, and the strength and the product of strength and strength of the steel are low.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides the austenitic low-density hot rolled steel which has the yield strength of 1653-1721 MPa, the tensile strength of 2035-2119 MPa and the elongation of 52-62% and is simple in production process and the production method thereof.
The measures for realizing the aim are as follows:
a high manganese high aluminum steel with ultra-fine grain size and thin specification comprises the following components by weight percent: c: 0.91-1.35%, Si: 0.21 to 0.53%, Mn: 8.5-16.2%, Al: 13.7-22.4%, Nb: 0.11-0.23%, V: 0.15-0.32%, P: less than or equal to 0.018%, S: less than or equal to 0.008 percent, N: less than or equal to 0.008 percent, and the balance of Fe and inevitable impurities; mechanical properties: the yield strength is 1653-1721 MPa, the tensile strength is 2035-2119 MPa, the elongation is 52-62%, the finished product structure mainly comprises retained austenite and martensite, the volume ratio of the retained austenite is not less than 85%, the size of austenite grains is 1.1-2.7 um, and the thickness of the strip steel is 0.04-0.59 mm.
Preferably: the Nb content is 0.13-0.21 wt%.
The method for producing the high-manganese high-aluminum steel with the ultra-fine grain size and thin specification comprises the following steps of:
1) smelting and continuously casting into a blank, wherein in the casting period, the blank drawing speed is controlled to be 3.5-5.1 m/min, and the thickness of the casting blank is controlled to be 52-70 mm;
2) heating the casting blank in a tunnel furnace, wherein the heating temperature is controlled to be 1183-1257 ℃, and the heating time is controlled to be 25-41 min;
3) carrying out high-pressure water descaling, wherein the descaling water pressure is controlled to be 31-41 MPa;
4) and 7, performing finish rolling on the stand, and controlling: the 1 st frame reduction rate is not less than 62%, and the 2 nd frame reduction rate is not less than 55%; the temperature of the strip steel at the outlet of the 7 th rack is 723-907 ℃; the thickness of the hot rolled strip steel is 0.8-2.2 mm;
5) carrying out laminar cooling, and cooling to a coiling temperature at a cooling speed of 83-163 ℃/s;
6) coiling at 251-327 ℃;
7) naturally cooling to room temperature;
8) performing cold rolling, and controlling the accumulated reduction rate to be 73-95%; the thickness of the rolled strip steel is 0.04-0.59 mm;
9) carrying out continuous annealing: firstly, heating to 880-935 ℃ at a heating speed of not less than 83 ℃/s, and staying at the temperature for 4-15 min; cooling to 327-415 ℃ at a speed of not less than 83 ℃/s, and staying at the temperature for 13-20 min; then naturally cooling to room temperature.
Preferably: the cooling speed in the continuous annealing is 95-143 ℃.
Preferably: the laminar cooling speed is 95-163 ℃/s.
Mechanism and action of each element and main process in the invention
The C element is an austenite stabilizing element, can enlarge an austenite phase region, postpone the phase transformation of ferrite and bainite, and reduce the transformation temperature of martensite. However, if the C content is too high, the weldability of the steel deteriorates rapidly, and the C content in the present invention should be controlled to 0.91 to 1.35%.
Si element is a ferrite-forming element, and the S content in the present invention should not be excessively high in order to avoid formation of a large amount of ferrite. In addition, Si can play a role in solid solution strengthening in steel, and is a deoxidizing element, so that the Si content in the steel is not too low in order to ensure the deoxidizing effect, and the Si content in the invention is controlled to be 0.21-0.53%.
Mn is an austenite stabilizing element, and can enlarge an austenite region and improve the hardenability of the steel plate, so that the Mn content should not be too low. In addition, when the Mn content is too high, a band-shaped structure is easily formed, and the weldability of the steel material is greatly lowered, which is not favorable for improving the overall properties of the steel material. The Mn content is controlled to be 8.5-16.2%.
The A1 element can effectively inhibit the precipitation of cementite and improve the stability of austenite, and in addition, the Al element can also effectively reduce the density of steel and effectively lighten the steel, so the Al content in the steel is not excessively low. However, when the content of Al in steel is too high, a nozzle is easily blocked in the continuous casting process, so that the molten steel is difficult to pour smoothly. The Al content of the invention is controlled to be 13.7-22.4%.
Nb element is a strong carbonitride forming element, and a small amount of Nb is added into the steel to inhibit the recrystallization of deformed austenite, prevent the growth of austenite grains, refine the grains and improve the strength and toughness of the steel. An excessively low Nb content makes it difficult to suppress the growth of austenite grains, an excessively high Nb content causes unnecessary alloy waste, and the Nb content is controlled to 0.11 to 0.23%, preferably 0.13 to 0.21% in the present invention.
The V element is a strong carbonitride forming element, and the strength and the toughness of the steel can be improved by adding a certain amount of V into the steel. In addition, the carbonitride of V has a large solid solubility product at high temperature and a small solid solubility product at low temperature, so that fine V (CN) and VC particles are easy to precipitate at low temperature, the fine precipitates can play a role of precipitation strengthening and can effectively improve the mechanical property of steel, and the content of V in the invention is controlled to be 0.15-0.32%.
Because a certain amount of Nb and V are added and the production process is matched, the austenite grain size of the high-manganese high-aluminum steel is greatly refined, and a good precipitation strengthening effect is obtained, so that the performance of the high-manganese high-aluminum steel is greatly improved compared with that of the prior patent.
The P element can reduce the toughness of the steel, particularly drastically reduce the low-temperature impact toughness of the steel, is a harmful element in the steel, and should be avoided as much as possible, and the P content should be controlled below 0.018% in combination with the actual production control level.
The S element is easy to combine with Mn in the steel to form MnS inclusion, thereby generating obvious difference in longitudinal and transverse properties of the steel and deteriorating the low-temperature toughness of the steel, and the S content in the invention is controlled below 0.008 percent.
The N element is a harmful element in steel, and when the content of the N element is too high, bubbles and looseness are easily formed in the steel, so that the quality of a casting blank is reduced, and therefore, the content of the N element is controlled within 0.008%.
According to the invention, the thickness of the cast blank after casting is controlled to be 52-70 mm, and the continuous casting drawing speed is controlled to be 3.5-5.1 m/min, because the subsequent rolling capability is insufficient due to too thick thickness of the cast blank, a finished product within a target thickness range cannot be obtained by rolling; the thickness of the casting blank is too thin, so that the total compression ratio in the subsequent rolling process is small, the recrystallization of the finished product is insufficient, the mixed crystals of the finished product are caused, and the quality of the finished product is seriously influenced. The drawing speed is too fast or too slow, so that the thickness of the liquid slag layer is unstable, and continuous casting breakout is easily caused.
The method emphasizes that a casting blank is heated in a tunnel furnace, the heating temperature is controlled to be 1183-1257 ℃, the heating time is 25-41 min, for example, due to the fact that the microalloy elements in the steel are difficult to fully dissolve due to too low heating temperature, the microalloy elements are difficult to play a role in solid solution strengthening and precipitation strengthening in the subsequent production process, and in addition, due to the fact that too low heating temperature, the deformation resistance in the rolling process is too large, and therefore the strip steel with the target thickness is difficult to roll; if the heating temperature is too high, the heating capacity of the heating furnace is exceeded, and the service life of the heating furnace is influenced. Too short a heating time may result in non-uniform temperature of the cast slab, and thus non-uniform product properties. The long heating time can cause serious decarburization on the surface of the casting blank, and the comprehensive performance of the steel strip is influenced.
The present invention is used for high-pressure water descaling, and the pressure of the descaling water is required to be 31-41 MPa. The scale removing water pressure is too low, the scale on the surface of the strip steel is difficult to remove, the surface defects of the strip steel can be caused after rolling, and the scale removing water pressure exceeds the capacity of equipment when being too high.
According to the invention, 7-stand finish rolling is carried out, and the 1 st stand reduction rate is controlled to be not less than 62%, and the 2 nd stand reduction rate is controlled to be not less than 55%. The temperature of the strip steel at the outlet of the 7 th rack is controlled to be 723-907 ℃. Because the low reduction rate of the No. 1 and No. 2 frames can lead to incomplete austenite recrystallization at high temperature, lead to mixed crystal of product tissues and lower the product quality, and also lead to difficult deformation induction precipitation of microalloy elements in the rolling process, lead to difficult refinement of austenite grains at high temperature and lower the comprehensive performance of strip steel; when the temperature of the steel strip at the outlet of the 7 th rack is too low, the deformation resistance of the rack is too large, the rolling is difficult, when the temperature of the steel strip at the outlet of the 7 th rack is too low, the rolling temperature of the steel strip is too high, the steel strip is recovered in the rolling process, austenite grains of the steel strip are large, and the comprehensive performance of the steel strip is reduced. The thickness range of the hot rolled strip steel is 0.8-2.2 mm.
The laminar cooling is carried out at a cooling speed of 83-163 ℃/s, because V is precipitated in the cooling process due to the excessively low laminar cooling speed and coarsened in the subsequent coiling process and annealing process, thereby weakening the precipitation strengthening effect. Too high a cooling rate on the one hand makes the capacity of the plant difficult to achieve and on the other hand leads to poor strip shape.
The coiling temperature is controlled to be 251-327 ℃, because the coiling temperature is too low, a large amount of martensite transformation can occur, and the comprehensive mechanical property of the strip steel is reduced. And on the other hand, the high coiling temperature can cause a large amount of V to be separated out in the coiling process and coarsen in the cooling process after coiling, so that the precipitation strengthening effect of the microalloy elements is weakened.
The invention is used for carrying out multi-pass cold rolling after the strip steel is naturally cooled to room temperature after being coiled, and controlling the cumulative reduction rate of the cold rolling to be 73-95% so as to obtain the deformed austenite with enough deformation energy storage, so that the austenite can be fully recrystallized and refined in the subsequent annealing process, and the comprehensive mechanical property of the strip steel is improved. The small cold rolling deformation can cause the deformation energy storage of austenite to be low, and the subsequent process is difficult to fully refine.
The invention carries out continuous annealing treatment, and aims to: on one hand, the band steel can fully complete recrystallization, so that crystal grains are fully refined, and the comprehensive performance of the band steel is improved; on the other hand, the annealing can eliminate the surface temperature unevenness of the strip steel caused by rapid heating, and the internal organization structure of the strip steel is uniform; the V microalloy precipitate can be fully precipitated in the process of re-annealing, so that the comprehensive mechanical property of the strip steel is improved. The temperature is quickly increased to 880-935 ℃ at a temperature increase speed of more than or equal to 83 ℃/s, and the temperature is kept for 4-15 min, because the micro-alloy precipitate of V is precipitated and coarsened at high temperature due to the over-low temperature increase speed, and the precipitation strengthening effect is weakened; if the temperature rise is too low and the residence time is too short, the deformed austenite is difficult to recrystallize, and austenite grains are difficult to refine. The temperature rise is too high, the retention time is too long, austenite grains grow up and coarsen, and the comprehensive performance of the strip steel is reduced.
After the high temperature section is controlled to be finished, the temperature is rapidly cooled to 327-415 ℃ at a speed of more than or equal to 83 ℃/s, and the temperature is kept for 13-20 min and then the temperature is naturally cooled to the room temperature. The reason is that when the cooling rate is too low, V microalloy precipitates are precipitated and coarsened at a high temperature, and the precipitation strengthening effect is weakened. If the temperature is too low and the residence time is too short, precipitates of V are difficult to separate out, so that the precipitation strengthening effect is weakened. The temperature reduction is too high, the retention time is too long, and precipitates of V are coarsened, so that the precipitation strengthening effect is weakened. The comprehensive mechanical property of the strip steel is reduced.
Compared with the prior art, the high-manganese high-aluminum steel disclosed by the invention has the advantages that the structure of the high-manganese high-aluminum steel is fully refined by reasonable composition and process control and combining the Nb microalloying technology, the grain refinement is an effective means for improving the strength and the plasticity at the same time, and the average grain size of the high-manganese high-aluminum steel disclosed by the invention is finer than that of the existing high-manganese high-aluminum steel. Meanwhile, under the combined action of strengthening modes such as precipitation strengthening of Nb and V microalloy, the yield strength of the high-manganese high-aluminum steel is 1653-1721 MPa, the tensile strength is 2035-2119 MPa, the elongation is 52-62%, the thickness of the high-manganese high-aluminum steel is thinner, compared with other high-manganese high-aluminum steels needing complex annealing process, the annealing process adopted is simpler, the annealing time is shorter, and the production efficiency is greatly improved.
Drawings
FIG. 1 is a metallographic structure of the present invention;
FIG. 2 is a graph showing precipitates in the present invention.
Detailed Description
The present invention is described in detail below:
table 1 is a list of values of the components of each example and comparative example of the present invention;
table 2 is a table of the main process parameters of each example of the present invention and comparative example;
table 3 is a table listing the main properties of each example of the present invention and comparative example;
table 4 list of parameters of the special mold flux for each example of the present invention and comparative example.
The preparation method of the invention comprises the following steps:
1) smelting and continuously casting into a blank, wherein in the casting period, the blank drawing speed is controlled to be 3.5-5.1 m/min, and the thickness of the casting blank is controlled to be 52-70 mm;
2) heating the casting blank in a tunnel furnace, controlling the heating temperature to 1183-1257 ℃, and controlling the heating time to 25-41 min;
3) carrying out high-pressure water descaling, wherein the descaling water pressure is controlled to be 31-41 MPa;
4) and 7, performing finish rolling on the stand, and controlling: the 1 st frame reduction rate is not less than 62%, and the 2 nd frame reduction rate is not less than 55%; the temperature of the strip steel at the outlet of the 7 th rack is 723-907 ℃; the thickness of the hot rolled strip steel is 0.8-2.2 mm;
5) carrying out laminar cooling, and cooling to a coiling temperature at a cooling speed of 83-163 ℃/s;
6) coiling at 251-327 ℃;
7) naturally cooling to room temperature;
8) performing cold rolling, and controlling the accumulated reduction rate to be 73-95%; the thickness of the rolled strip steel is 0.04-0.59 mm;
9) carrying out continuous annealing: firstly, heating to 880-935 ℃ at a heating speed of not less than 83 ℃/s, and staying at the temperature for 4-15 min; cooling to 327-415 ℃ at a speed of not less than 83 ℃/s, and staying at the temperature for 13-20 min; then naturally cooling to room temperature.
TABLE 1 ingredient lists (wt%) of inventive examples and comparative examples
TABLE 2 List of the main process parameters of the examples of the invention and the comparative examples
Table 3 main performance lists of inventive and comparative examples
From table 3, it can be found that the grain size of the high-manganese high-aluminum steel produced by the invention is far finer than that of the existing high-manganese high-aluminum steel, so that the fine grain strengthening effect of the high-manganese high-aluminum steel disclosed by the invention is far better than that of the existing high-manganese high-aluminum steel, and the yield strength, tensile strength, elongation and product of strength and elongation of the high-manganese high-aluminum steel disclosed by the invention are far better than the performance level of the existing reported high-manganese high-aluminum steel by matching with other strengthening modes.
The above examples are merely preferred examples and are not intended to limit the embodiments of the present invention.

Claims (6)

1. A high manganese high aluminum steel with ultra-fine grain size and thin specification comprises the following components by weight percent: c: 1.31 to 1.35%, Si: 0.22 to 0.53%, Mn: 8.5-14.9%, Al: 16.2-22.4%, Nb: 0.11-0.23%, V: 0.15-0.27% or V: 0.29-0.32%, P: less than or equal to 0.008 percent, S: less than or equal to 0.002%, N: less than or equal to 0.003 percent, and the balance of Fe and inevitable impurities; mechanical properties: the yield strength is 1653-1721 MPa, the tensile strength is 2035-2119 MPa, the elongation is 52-62%, the finished product structure mainly comprises retained austenite and martensite, the volume ratio of the retained austenite is not less than 85%, the size of austenite grains is 1.1-2.7 um, and the thickness of the strip steel is 0.04-0.59 mm; the production method comprises the following steps:
1) smelting and continuously casting into a blank, wherein in the casting period, the blank drawing speed is controlled to be 3.5-5.1 m/min, and the thickness of the casting blank is controlled to be 52-70 mm;
2) heating the casting blank in a tunnel furnace, controlling the heating temperature to 1183-1257 ℃, and controlling the heating time to 25-41 min;
3) carrying out high-pressure water descaling, wherein the descaling water pressure is controlled to be 31-41 MPa;
4) and 7, performing finish rolling on the stand, and controlling: the 1 st frame reduction rate is not less than 62%, and the 2 nd frame reduction rate is not less than 55%; the temperature of the strip steel at the outlet of the 7 th rack is 723-779 ℃; the thickness of the hot rolled strip steel is 0.8-2.2 mm;
5) carrying out laminar cooling, and cooling to a coiling temperature at a cooling speed of 83-163 ℃/s;
6) coiling at 251-327 ℃;
7) naturally cooling to room temperature;
8) performing cold rolling, and controlling the accumulated reduction rate to be 82-95%; the thickness of the rolled strip steel is 0.04-0.59 mm;
9) carrying out continuous annealing: firstly, heating to 880-935 ℃ at a heating rate of 83-156 ℃/s, and staying at the temperature for 6-15 min; cooling to 327-394 ℃ at the speed of 83-154 ℃/s, and staying at the temperature for 13-20 min; then naturally cooling to room temperature.
2. The ultra-fine grain size thin gauge high manganese high aluminum steel of claim 1, wherein: the Nb content is 0.13-0.21 wt%.
3. The method for producing an ultra-fine grain size thin gauge high manganese high aluminum steel as claimed in claim 1, comprising the steps of:
1) smelting and continuously casting into a blank, wherein in the casting period, the blank drawing speed is controlled to be 3.5-5.1 m/min, and the thickness of the casting blank is controlled to be 52-70 mm;
2) heating the casting blank in a tunnel furnace, controlling the heating temperature to 1183-1257 ℃, and controlling the heating time to 25-41 min;
3) carrying out high-pressure water descaling, wherein the descaling water pressure is controlled to be 31-41 MPa;
4) and 7, performing finish rolling on the stand, and controlling: the 1 st frame reduction rate is not less than 62%, and the 2 nd frame reduction rate is not less than 55%; the temperature of the strip steel at the outlet of the 7 th rack is 723-779 ℃; the thickness of the hot rolled strip steel is 0.8-2.2 mm;
5) carrying out laminar cooling, and cooling to a coiling temperature at a cooling speed of 83-163 ℃/s;
6) coiling at 251-327 ℃;
7) naturally cooling to room temperature;
8) performing cold rolling, and controlling the accumulated reduction rate to be 82-95%; the thickness of the rolled strip steel is 0.04-0.59 mm;
9) carrying out continuous annealing: firstly, heating to 880-935 ℃ at a heating rate of 83-156 ℃/s, and staying at the temperature for 6-15 min; cooling to 327-394 ℃ at the speed of 83-154 ℃/s, and staying at the temperature for 13-20 min; then naturally cooling to room temperature.
4. The method for producing an ultra-fine grain size thin gauge high manganese high aluminum steel as claimed in claim 3, wherein: the temperature rise speed in the continuous annealing is 89-143 ℃.
5. The method for producing an ultra-fine grain size thin gauge high manganese high aluminum steel as claimed in claim 3, wherein: the cooling speed in the continuous annealing is 95-143 ℃.
6. The method for producing an ultra-fine grain size thin gauge high manganese high aluminum steel as claimed in claim 3, wherein: the laminar cooling speed is 95-163 ℃/s.
CN202010626267.7A 2020-07-02 2020-07-02 Ultra-fine grain size thin-specification high-manganese high-aluminum steel and production method thereof Active CN111647818B (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107058854A (en) * 2017-03-13 2017-08-18 昆明理工大学 A kind of vacuum smelting method of the high manganese high-aluminum steel of Nb, V, Ti microalloying
CN108642403A (en) * 2018-05-28 2018-10-12 河北工业大学 A kind of 780MPa grade super strengths Fe-Mn-Al-C systems lightweight cast steel and preparation method thereof
CN109154049A (en) * 2016-05-24 2019-01-04 安赛乐米塔尔公司 The purposes of steel plate, its manufacturing method and such steel to manufacture vehicle part through cold rolling and annealing

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109154049A (en) * 2016-05-24 2019-01-04 安赛乐米塔尔公司 The purposes of steel plate, its manufacturing method and such steel to manufacture vehicle part through cold rolling and annealing
CN107058854A (en) * 2017-03-13 2017-08-18 昆明理工大学 A kind of vacuum smelting method of the high manganese high-aluminum steel of Nb, V, Ti microalloying
CN108642403A (en) * 2018-05-28 2018-10-12 河北工业大学 A kind of 780MPa grade super strengths Fe-Mn-Al-C systems lightweight cast steel and preparation method thereof

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