CN112195392A - 700 MPa-grade cold-rolled low-alloy high-strength steel and production method thereof - Google Patents
700 MPa-grade cold-rolled low-alloy high-strength steel and production method thereof Download PDFInfo
- Publication number
- CN112195392A CN112195392A CN202010985837.1A CN202010985837A CN112195392A CN 112195392 A CN112195392 A CN 112195392A CN 202010985837 A CN202010985837 A CN 202010985837A CN 112195392 A CN112195392 A CN 112195392A
- Authority
- CN
- China
- Prior art keywords
- rolled
- cold
- rolling
- steel
- coil
- 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.)
- Granted
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
-
- 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
- C21D8/0236—Cold 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
- 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
- C21D8/0278—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular surface 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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
Abstract
The invention relates to a method for producing 700 MPa-grade cold-rolled low-alloy high-strength steel based on double-roller casting rolling. The molten steel comprises the following chemical components in percentage by mass: c is less than or equal to 0.05 percent; si: 0.16-0.5%; mn: 1.1-1.5%; nb: 0.045-0.065%; cr: 0.10-0.40%; p is less than or equal to 0.02 percent; s is less than or equal to 0.0040 percent; the balance being Fe and unavoidable impurities. The method of the invention firstly adopts a double-roller casting and rolling process and adopts an ultra-fast cooling technology to produce the hot-rolled thin strip with the functions of strengthening the structure and strengthening the aging. Then, the method adopts a reversible rolling mill to perform one-time cold rolling at the reduction rate of 10-20%, and the cold-rolled steel coil is subjected to cover annealing to obtain an annealed finished coil after flattening. Compared with the traditional production process, the method for producing the cold-rolled low-alloy high-strength steel can improve the production efficiency and reduce the production cost and the production difficulty.
Description
Technical Field
The invention belongs to the technical field of metallurgical industry, and particularly relates to a method for producing cold-rolled low-alloy high-strength steel based on double-roller casting rolling.
Background
With the continuous improvement of the requirements of energy conservation, environmental protection, collision safety performance and the like, the automobile body is widely made of high-strength automobile steel plates during design and manufacture. The application proportion of high-strength steel parts on the automobile body reaches the level of 40-80%, and the demand of high-strength steel is increased year by year. The cold-rolled low-alloy high-strength steel belongs to a series commonly used in automobile high-strength steel, and is difficult to roll high-strength steel plates in the traditional production process, and has high requirements on equipment capacity of a rolling mill, particularly a cold rolling mill.
The ultra-fast cooling technique of the twin roll casting process can provide a strengthened structure in the steel sheet with improved strength. Therefore, compared with the traditional process, under the same strength, the double-roller casting and rolling process can reduce the addition amount of the alloy and the alloy cost for producing the high-strength steel. However, the twin roll casting process produces hot rolled thin strip with inferior surface quality and sheet shape to cold rolled steel sheets. The surface quality and the plate shape of the steel plate can meet the requirements of a cold-rolled steel plate by rolling the hot-rolled thin strip produced by the double-roller casting and rolling process by adopting the single stand. However, if the cold rolling reduction is too large, the original strengthened structure in the steel sheet disappears in the subsequent annealing process, which is also disadvantageous in terms of mechanical properties of the steel sheet.
Disclosure of Invention
The invention aims to provide a method for producing 700 MPa-grade cold-rolled low-alloy high-strength steel based on double-roller casting rolling, so as to overcome many defects in the prior art.
Compared with a five-stand continuous rolling mode of a cold rolling procedure in the traditional process, the production method of the cold-rolled low-alloy high-strength steel only needs one-pass low reduction rate rolling, and the production difficulty of the high-strength cold-rolled low-alloy high-strength steel is reduced. According to the method of the present invention, cold rolling uses a small reduction ratio, so that the strengthened structure can be retained during annealing. Further, the steel plate is rolled at a small reduction ratio, the number of dislocation in the steel plate can be increased, the aging strengthening effect in the annealing process is enhanced, and the strength of the steel plate is further improved.
In order to achieve the purpose, the invention adopts the following technical scheme.
According to a first aspect of the present invention, there is provided a method for producing cold-rolled low-alloy high-strength steel based on twin-roll casting, comprising the steps of:
(1) adopting an electric furnace for smelting, mixing the following chemical components in percentage by mass,
C≤0.05％；
Si：0.16～0.5％；
Mn：1.1～1.5％；
Nb：0.045～0.065％；
Cr：0.10～0.40％；
P≤0.02％；
S≤0.0040％；
the balance of Fe and inevitable impurities;
(2) continuously casting the molten steel obtained in the step (1) into a thin strip to obtain a cast strip;
(3) carrying out hot rolling on the cast strip obtained in the step (2) for one time to obtain a hot-rolled thin strip, cooling by using aerial fog, and coiling to obtain a hot-rolled coil;
(4) pickling the hot rolled coil obtained in the step (3) by using a pickling line to obtain a pickled coil;
(5) rolling the acid-washed coil obtained in the step (4) into a hard-rolled coil through a reversible single machine frame;
(6) annealing the rolled hard coil obtained in the step (5) in a cover type annealing furnace to obtain an annealed coil;
(7) and (4) flattening the steel coil annealed in the step (6) on a flattening machine to obtain a cold-rolled annealed finished product coil.
In the molten steel components of the cold-rolled low-alloy high-strength steel, the prior art is broken through, and the high Cr content is adopted: 0.10-0.40%, so that the performance of the cold-rolled low-alloy high-strength steel is more stable, more rapid cooling strengthening structures can be obtained after rapid cooling, and the comprehensive mechanical properties are more advantageous.
According to the method for producing the cold-rolled low-alloy high-strength steel based on the double-roller casting rolling, the electric furnace smelting, the VD vacuum furnace degassing and the LF furnace refining are adopted in the step (1), and molten steel with qualified components is obtained.
According to the method for producing the cold-rolled low-alloy high-strength steel based on the twin-roll casting, preferably, in the step (2), the molten steel is continuously cast by using a twin-roll casting process, the casting temperature of the molten steel is 1500-1600 ℃, the casting speed is 20-120 m/min, and the molten steel is continuously cast into thin strips under the protection of inert gas.
According to the method for producing the cold-rolled low-alloy high-strength steel based on the twin-roll casting, the thickness of the cast strip in the step (2) is preferably 1.4-2.5 mm.
According to the method for producing the cold-rolled low-alloy high-strength steel based on the double-roller casting rolling, preferably, the cast strip in the step (3) is subjected to one-time hot rolling, the reduction rate is 10-50%, the hot rolling outlet temperature is 850-1050 ℃, the strip steel temperature after aerial fog cooling is 450-550 ℃, the cooling rate is 30-80 ℃/s, and the thickness is 0.9-1.8 mm.
In the process parameters, the lower cooling temperature of the gas mist is 450-550 ℃, and more rapid cooling strengthening structures can be obtained after rapid cooling by matching with the Cr element with higher content in the molten steel.
According to the method for producing the cold-rolled low-alloy high-strength steel based on the twin-roll casting rolling, preferably, in the step (5), the pickling coil is subjected to one-time cold rolling by a reversible rolling mill at a reduction ratio of 10-20%.
In the method, a reversible rolling mill is adopted to carry out one-time cold rolling at the reduction rate of 10-20%, so that the method has an important technical purpose. Specifically, one-pass cold rolling at a small reduction ratio:
firstly, in the subsequent annealing process, the reinforced structure obtained by the double-roller casting and rolling process can be retained in the subsequent annealing process;
the dislocation quantity in the steel plate is increased, the aging strengthening effect in the annealing process is enhanced, and the strength of the steel plate is further improved;
and thirdly, the surface quality of the steel plate is improved.
According to the method for producing the cold-rolled low-alloy high-strength steel based on the double-roller casting rolling, the thickness of a hard roll obtained after the cold rolling is preferably 0.8-1.5 mm.
According to the method for producing the cold-rolled low-alloy high-strength steel based on the twin-roll casting, preferably, in the step (6), when annealing is performed by using a hood-type annealing furnace, the steel is heated to 450-650 ℃ at a heating rate of 10-50 ℃/s for heat preservation, and the heat preservation time is 1-20 hours.
The method adopts the cover type annealing process, and compared with the continuous annealing process, the method has the advantages of small equipment investment and low production cost. Furthermore, among the technological parameters of the cover annealing, the annealing temperature is low, the annealing time is long, alloy elements which are dissolved in the production process of the double-roller casting-rolling ultra-fast cooling technology can be dispersed and precipitated more finely and fully in the form of carbide, the aging strengthening effect is generated, and the strength of the cold-rolled low-alloy high-strength steel is obviously improved.
According to the method for producing the cold-rolled low-alloy high-strength steel based on the twin-roll casting, the flat elongation in the step (7) is preferably 0.8-1.5%.
According to a second aspect of the invention, there is also provided a cold-rolled low-alloy high-strength steel produced by the above method for producing cold-rolled low-alloy high-strength steel based on twin-roll casting.
According to the cold-rolled low-alloy high-strength steel, the yield strength of the cold-rolled low-alloy high-strength steel is 620-700 MPa, the tensile strength of the cold-rolled low-alloy high-strength steel is 700-800 MPa, and the elongation of the cold-rolled low-alloy high-strength steel is 10-20%.
Advantageous technical effects
Compared with the prior art, the invention has the advantages that:
(1) compared with the traditional hot rolling production line, the double-roller casting and rolling process for producing the hot rolled base plate required by the cold-rolled low-alloy high-strength steel, provided by the invention, has the advantages that the heating furnace is eliminated, the number of frames of the hot rolling mill is reduced, the energy consumption required by production is greatly reduced, and the production cost and the working procedure time are reduced. In addition, the ultra-fast cold rolling technology of the double-roller casting and rolling process can obtain a strengthened structure with improved strength in the steel plate, so that compared with the traditional process, the double-roller casting and rolling process is adopted to produce high-strength steel under the same strength, the addition amount of alloy can be reduced, and the alloy cost is reduced.
(2) The molten steel components of the cold-rolled low-alloy high-strength steel break through the prior art, and adopt higher Cr content: 0.10-0.40%, so that the performance of the cold-rolled low-alloy high-strength steel is more stable, more rapid cooling strengthening structures can be obtained after rapid cooling, and the comprehensive mechanical properties are more advantageous.
(3) In the cooling parameters of the hot rolled strip, the lower gas spray cooling temperature is 450-550 ℃, and more rapid cooling strengthening structures can be obtained after rapid cooling by matching with the Cr element with higher content in the molten steel.
(4) Compared with the multi-pass and high reduction ratio process of the conventional cold rolling process, the hot rolling thin strip produced by the double-roll casting process is only rolled at a small reduction ratio for one pass, so that the production cost and the process time of the cold rolling process are reduced. Further, in the subsequent annealing process of one-time cold rolling with small reduction ratio, the fast cooling strengthened structure obtained by the double-roller casting rolling process can be reserved; the dislocation number in the steel plate is increased, the aging strengthening effect in the annealing process is enhanced, and the strength of the steel plate is further improved; in addition, the surface quality of the steel sheet is improved.
(5) The method adopts the cover type annealing process, and compared with the continuous annealing process, the method has the advantages of small equipment investment and low production cost. Furthermore, among the technological parameters of the cover annealing, the annealing temperature is low, the annealing time is long, alloy elements which are dissolved in the production process of the double-roller casting-rolling ultra-fast cooling technology can be dispersed and precipitated more finely and fully in the form of carbide, the aging strengthening effect is generated, and the strength of the cold-rolled low-alloy high-strength steel is obviously improved.
(6) The production method of the cold-rolled low-alloy high-strength steel provided by the invention can greatly reduce the load of a rolling mill during rolling due to the reduction of the rolling reduction rate and pass of the hot rolling process and the cold rolling process. On the other hand, different from the cold-rolled low-alloy high-strength steel produced by the traditional process (the strength of a hot-rolled plate is reduced and the plasticity is increased after cold-rolling and annealing), the method provided by the invention can be used for producing the cold-rolled low-alloy high-strength steel, and the strength and the plasticity of the hot-rolled plate are obviously increased after cold-rolling and annealing due to the aging strengthening effect. Therefore, under the condition that the strength of the final product is the same, the strength of the hot rolled plate used by the production method provided by the invention is lower than that of the traditional production process, and the load of a rolling mill during rolling can be reduced.
(7) The synergistic effect of the molten steel components (high Cr content), the lower quick cooling temperature range, the one-pass cold rolling of small reduction rate, the cover annealing process, parameters and the like enables the cold-rolled low-alloy high-strength steel produced by the method disclosed by the invention to have excellent comprehensive mechanical properties compared with the prior art, wherein the yield strength is 620-700 MPa, the tensile strength is 700-800 MPa, and the elongation is 10-20%.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly described below. It is to be understood that the drawings in the following description are directed to only some embodiments of the invention and are not intended as a limitation on the invention.
FIG. 1 is a schematic flow diagram of the process for producing 700MPa grade cold rolled low alloy high strength steel according to the method of the present invention;
FIG. 2 is a metallographic structure diagram of a 700MPa grade cold rolled low alloy high strength steel according to example 1 of the present invention;
FIG. 3 is a metallographic structure diagram of a 700MPa grade cold rolled low alloy high strength steel according to example 2 of the present invention;
FIG. 4 is a metallographic structure diagram of a 700MPa grade cold rolled low alloy high strength steel according to example 3 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs.
A schematic of the overall process flow employed by an embodiment of the present invention is shown, for example, in fig. 1.
Referring to fig. 1, in various embodiments, the method for producing 700MPa grade cold-rolled low-alloy high-strength steel based on strip casting mainly comprises the following steps and process parameters.
Example 1
FIG. 1 is a schematic flow chart of the process for producing 700MPa cold-rolled low-alloy high-strength steel according to the method of the invention.
Referring to fig. 1, the method according to the present invention comprises the following steps.
(1) Smelting molten steel: the molten steel with qualified components is obtained by electric furnace steelmaking, VD vacuum furnace degassing and LF furnace refining, and the molten steel comprises the following components in percentage by weight: c: 0.023%; si: 0.22 percent; mn: 1.40 percent; nb: 0.058%; cr: 0.20 percent; p: 0.01 percent; s: 0.002%; the balance of iron and inevitable impurity elements.
(2) Strip continuous casting: and continuously casting the qualified molten steel by using a twin-roll casting and rolling process, wherein the casting temperature of the molten steel is 1520 ℃, the casting and rolling speed is 65m/min, and the molten steel is subjected to strip continuous casting under the protection of inert gas, and the thickness of a casting strip is 2.45 mm.
(3) Hot rolling: the cast strip is hot-rolled into a hot-rolled thin strip with the thickness of 1.70mm by one time at the reduction ratio of 31 percent, the hot-rolled outlet temperature is 867 ℃, and the strip steel temperature is 530 ℃ after aerial fog cooling.
(4) Acid washing: and (3) pickling the hot-rolled thin strip by using a pickling line to remove the iron oxide scales on the surface of the steel plate.
(5) Cold rolling: and (3) rolling the acid-washed hot-rolled thin strip into a 1.50mm hard roll by a reversing rolling mill for one time, wherein the reduction rate is 12%.
(6) Cover annealing: when the hard rolled coil is annealed by adopting a hood-type annealing furnace, the hard rolled coil is heated to 600 ℃ at the heating rate of 40 ℃/s for heat preservation for 1 h.
(7) Leveling: the annealed steel coil is leveled by a leveling machine, and the leveling elongation is 1.2%.
The mechanical properties of the high-strength steel, the hot-rolled thin strip and the annealed finished coil manufactured according to the components and the process are as follows:
TABLE 1 anisotropy of mechanical Properties of Cold-rolled Low-alloy high-Strength Steel of example 1
According to the method of example 1, the metallographic structure of the obtained 700MPa grade cold rolled low alloy high strength steel is shown in fig. 2, for example.
Example 2
FIG. 1 is a schematic flow chart of the process for producing 700MPa cold-rolled low-alloy high-strength steel according to the method of the invention.
Referring to fig. 1, the method according to the present invention comprises the following steps.
(1) Smelting molten steel: the molten steel with qualified components is obtained by electric furnace steelmaking, VD vacuum furnace degassing and LF furnace refining, and the molten steel comprises the following components in percentage by weight: c: 0.030%; si: 0.43 percent; mn: 1.32 percent; nb: 0.050%; cr: 0.18 percent; p: 0.01 percent; s: 0.003%; the balance of iron and inevitable impurity elements.
(2) Strip continuous casting: and continuously casting the qualified molten steel by using a twin-roll casting and rolling process, wherein the casting temperature of the molten steel is 1524 ℃, the casting and rolling speed is 70m/min, and the molten steel is subjected to strip continuous casting under the protection of inert gas, wherein the thickness of a casting strip is 2.25 mm.
(3) Hot rolling: the cast strip is hot-rolled into a hot-rolled thin strip with the thickness of 1.4mm by one time at the reduction rate of 38 percent, the hot-rolled outlet temperature is 860 ℃, and the strip steel temperature is 480 ℃ after aerial fog cooling.
(4) Acid washing: and (3) pickling the hot-rolled thin strip by using a pickling line to remove the iron oxide scales on the surface of the steel plate.
(5) Cold rolling: and (3) rolling the acid-washed hot-rolled thin strip into a 1.2mm hard roll by a reversible rolling mill for one time, wherein the reduction rate is 14%.
(6) Cover annealing: when the hard rolled coil is annealed by adopting a hood-type annealing furnace, the hard rolled coil is heated to 500 ℃ at the heating rate of 40 ℃/s for heat preservation for 15 h.
(7) Leveling: the annealed steel coil is leveled by a leveling machine, and the leveling elongation is 1.1%.
The mechanical properties of the high-strength steel, the hot-rolled thin strip and the annealed finished coil manufactured according to the components and the process are as follows:
TABLE 2 Anisotropic mechanical Properties of the Cold-rolled Low-alloy high-Strength Steel of example 2
According to the method of example 2, the metallographic structure of the obtained 700MPa grade cold rolled low alloy high strength steel is shown in fig. 3, for example.
Example 3
FIG. 1 is a schematic flow chart of the process for producing 700MPa cold-rolled low-alloy high-strength steel according to the method of the invention.
Referring to fig. 1, the method according to the present invention comprises the following steps.
(1) Smelting molten steel: the molten steel with qualified components is obtained by electric furnace steelmaking, VD vacuum furnace degassing and LF furnace refining, and the molten steel comprises the following components in percentage by weight: c: 0.030%; si: 0.36 percent; mn: 1.21 percent; nb: 0.046 percent; cr: 0.28 percent; p: 0.01 percent; s: 0.002%; the balance of iron and inevitable impurity elements.
(2) Strip continuous casting: and continuously casting the qualified molten steel by using a twin-roll casting and rolling process, wherein the casting temperature of the molten steel is 1552 ℃, the casting and rolling speed is 73m/min, and the molten steel is subjected to thin-strip continuous casting under the protection of inert gas, wherein the thickness of a cast strip is 1.85 mm.
(3) Hot rolling: the cast strip is hot-rolled into a hot-rolled thin strip with the thickness of 1.2mm by one time at the reduction rate of 35 percent, the hot-rolled outlet temperature is 855 ℃, and the strip steel temperature is 473 ℃ after aerial fog cooling.
(4) Acid washing: and (3) pickling the hot-rolled thin strip by using a pickling line to remove the iron oxide scales on the surface of the steel plate.
(5) Cold rolling: and (3) rolling the acid-washed hot-rolled thin strip into a 1.0mm hard roll by a reversible rolling mill for one time, wherein the reduction rate is 17%.
(6) Cover annealing: when the hard rolled coil is annealed by adopting a hood-type annealing furnace, the hard rolled coil is heated to 550 ℃ at the heating rate of 40 ℃/s for heat preservation for 4 h.
(7) Leveling: the annealed steel coil is leveled by a leveling machine, and the leveling elongation is 0.9%.
The mechanical properties of the high-strength steel, the hot-rolled thin strip and the annealed finished coil manufactured according to the components and the process are as follows:
TABLE 3 Anisotropic mechanical Properties of Cold rolled Low alloy high Strength Steel of example 3
According to the method of example 3, the metallographic structure of the obtained 700MPa grade cold rolled low alloy high strength steel is shown in fig. 4, for example.
The foregoing is directed to embodiments of the present invention and it is noted that various modifications and adaptations of the invention may occur to those skilled in the art without departing from the scope and spirit of the invention.
Claims (11)
1. A method for producing cold-rolled low-alloy high-strength steel based on twin-roll casting rolling is characterized by comprising the following steps:
(1) adopting an electric furnace for smelting, mixing the following chemical components in percentage by mass,
C≤0.05％；
Si：0.16～0.5％；
Mn：1.1～1.5％；
Nb：0.045～0.065％；
Cr：0.10～0.40％；
P≤0.02％；
S≤0.0040％；
the balance of Fe and inevitable impurities;
(2) continuously casting the molten steel obtained in the step (1) into a thin strip to obtain a cast strip;
(3) carrying out hot rolling on the cast strip obtained in the step (2) for one time to obtain a hot-rolled thin strip, cooling by using aerial fog, and coiling to obtain a hot-rolled coil;
(4) pickling the hot rolled coil obtained in the step (3) by using a pickling line to obtain a pickled coil;
(5) rolling the acid-washed coil obtained in the step (4) into a hard-rolled coil through a reversible single machine frame;
(6) annealing the rolled hard coil obtained in the step (5) in a cover type annealing furnace to obtain an annealed coil;
(7) and (4) flattening the steel coil annealed in the step (6) on a flattening machine to obtain a cold-rolled annealed finished product coil.
2. The method of claim 1, wherein: in the step (1), electric furnace smelting, VD vacuum furnace degassing and LF furnace refining are adopted to obtain molten steel with qualified components.
3. The method of claim 1, wherein: and (2) continuously casting the molten steel by using a double-roller casting and rolling process, wherein the casting temperature of the molten steel is 1500-1600 ℃, the casting and rolling speed is 20-120 m/min, and the molten steel is subjected to strip continuous casting under the protection of inert gas.
4. The method of claim 3, wherein: in the step (2), the thickness of the casting belt is 1.4-2.5 mm.
5. The method of claim 1, wherein: and (3) carrying out one-time hot rolling on the cast strip in the step (3), wherein the reduction rate is 10-50%, the hot rolling outlet temperature is 850-1050 ℃, the temperature of the strip steel after aerial fog cooling is 450-550 ℃, the cooling rate is 30-80 ℃/s, and the thickness is 0.9-1.8 mm.
6. The method according to any one of claims 1-5, wherein: in the step (5), the acid-washed coil is subjected to one-time cold rolling by a reversible rolling mill at a reduction rate of 10-20%.
7. The method of claim 6, wherein: the thickness of the hard roll obtained after cold rolling is 0.8-1.5 mm.
8. The method according to any one of claims 1-5, wherein: and (6) when the cover annealing furnace is adopted for annealing, heating to 450-650 ℃ at a heating rate of 10-50 ℃/s for heat preservation for 1-20 h.
9. The method of claim 1, wherein: in the step (7), the flat elongation is 0.8-1.5%.
10. A cold-rolled low-alloy high-strength steel is characterized in that: the cold rolled low alloy high strength steel is produced with the method according to any one of claims 1-9.
11. The cold rolled low alloy high strength steel according to claim 10, characterized in that: the yield strength of the cold-rolled low-alloy high-strength steel is 620-700 MPa, the tensile strength is 700-800 MPa, and the elongation is 10-20%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010985837.1A CN112195392B (en) | 2020-09-18 | 2020-09-18 | 700 MPa-grade cold-rolled low-alloy high-strength steel and production method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010985837.1A CN112195392B (en) | 2020-09-18 | 2020-09-18 | 700 MPa-grade cold-rolled low-alloy high-strength steel and production method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112195392A true CN112195392A (en) | 2021-01-08 |
| CN112195392B CN112195392B (en) | 2022-04-26 |
Family
ID=74015481
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010985837.1A Active CN112195392B (en) | 2020-09-18 | 2020-09-18 | 700 MPa-grade cold-rolled low-alloy high-strength steel and production method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112195392B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102021472A (en) * | 2011-01-12 | 2011-04-20 | 钢铁研究总院 | Production method for continuous annealing process high strength and plasticity product automobile steel plate |
| CN104328360A (en) * | 2014-11-20 | 2015-02-04 | 北京科技大学 | Double-phase twinborn induced plastic super-strength automobile steel plate and preparation method thereof |
| CN108842024A (en) * | 2018-06-15 | 2018-11-20 | 甘肃酒钢集团宏兴钢铁股份有限公司 | A kind of phosphorous IF high-strength steel band of 390MPa grades of cold rolling and its LF-RH duplex production technology |
| CN111041365A (en) * | 2019-12-25 | 2020-04-21 | 江苏沙钢集团有限公司 | 500-700 MPa-level economical high-strength steel based on thin strip casting and rolling and production method thereof |
| CN111215590A (en) * | 2020-04-16 | 2020-06-02 | 江苏沙钢集团有限公司 | Thin-gauge cold-rolled low-alloy high-strength steel and production method thereof based on double-roller casting rolling |
-
2020
- 2020-09-18 CN CN202010985837.1A patent/CN112195392B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102021472A (en) * | 2011-01-12 | 2011-04-20 | 钢铁研究总院 | Production method for continuous annealing process high strength and plasticity product automobile steel plate |
| CN104328360A (en) * | 2014-11-20 | 2015-02-04 | 北京科技大学 | Double-phase twinborn induced plastic super-strength automobile steel plate and preparation method thereof |
| CN108842024A (en) * | 2018-06-15 | 2018-11-20 | 甘肃酒钢集团宏兴钢铁股份有限公司 | A kind of phosphorous IF high-strength steel band of 390MPa grades of cold rolling and its LF-RH duplex production technology |
| CN111041365A (en) * | 2019-12-25 | 2020-04-21 | 江苏沙钢集团有限公司 | 500-700 MPa-level economical high-strength steel based on thin strip casting and rolling and production method thereof |
| CN111215590A (en) * | 2020-04-16 | 2020-06-02 | 江苏沙钢集团有限公司 | Thin-gauge cold-rolled low-alloy high-strength steel and production method thereof based on double-roller casting rolling |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112195392B (en) | 2022-04-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109865742B (en) | Production method of thin hot-rolled pickled automobile plate with tensile strength of 440MPa | |
| CN107641759B (en) | Method for producing thin-specification hot forming steel based on CSP (cast Steel plate) process | |
| CN111215590B (en) | Thin-gauge cold-rolled low-alloy high-strength steel and production method thereof based on double-roller casting rolling | |
| CN109338236B (en) | Easily-welded carbon structural steel based on thin strip casting and rolling and manufacturing method thereof | |
| CN102925791B (en) | Steel easy to pickle and production method of steel | |
| CN107012392B (en) | A kind of 600MPa grade high-strength low-alloy cold-strip steel and its production method | |
| CN103173678A (en) | Non-oriented silicon steel for rotor and production method thereof | |
| CN107287513B (en) | A kind of tin plate and preparation method thereof | |
| CN109722599B (en) | Thick-specification automobile beam steel plate with tensile strength of 750MPa and preparation method thereof | |
| CN113774274B (en) | Low-cost well-formed battery case steel and production method thereof | |
| CN110983193A (en) | 800 MPa-grade high-strength steel based on thin strip casting and rolling and production method thereof | |
| CN113751679B (en) | Manufacturing method of cobalt-free maraging steel cold-rolled thin strip | |
| CN112195392B (en) | 700 MPa-grade cold-rolled low-alloy high-strength steel and production method thereof | |
| CN110358976A (en) | A kind of high-carbon steel strip and its production method | |
| CN109338238B (en) | Low-carbon steel for stamping based on thin strip casting and rolling and manufacturing method thereof | |
| CN115044831B (en) | 1100MPa grade cold-rolled martensitic steel and manufacturing method thereof | |
| CN110565024A (en) | Niobium-titanium-containing 550 MPa-grade thick weathering resistant steel and production method thereof | |
| CN107541663A (en) | A kind of beverage can ferrostan and its production method | |
| CN115522030A (en) | Martensite thin strip steel and production method thereof based on thin strip casting and rolling process | |
| CN115537661A (en) | 600 MPa-grade hot-galvanized dual-phase steel for automobile structure and production method thereof | |
| JPS582249B2 (en) | Continuous annealing method for cold rolled steel sheets for press forming | |
| CN112708827B (en) | Ultrathin steel strip for battery case and electronic basic element and manufacturing method thereof | |
| CN115386782A (en) | Low-cost high-strength galvanized sheet and manufacturing process of sandwich board thereof | |
| CN114015938A (en) | 240 MPa-grade cold-rolled carbon structural steel and production method thereof | |
| CN115011774B (en) | Method for producing high-surface-quality automobile girder steel by CSP |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |