CN112575257A - Low-cost boron-containing non-quenched and tempered 700MPa high-strength steel and manufacturing method thereof - Google Patents
Low-cost boron-containing non-quenched and tempered 700MPa high-strength steel and manufacturing method thereof Download PDFInfo
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- 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
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- 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
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- 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
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- 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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—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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- 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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/002—Bainite
Abstract
The invention discloses low-cost boron-containing non-quenched and tempered 700MPa high-strength steel, which is prepared by controlling [ N ], [ O ] and [ H ] in molten steel, adjusting the proportion of C, Mn and B in the steel, not adding noble metals Mo, Cr, Ni and Cu, and fully playing the role of C, Mn and B elements. The rolling steps in the manufacturing method are as follows: slab reheating temperature: 1200-1280 ℃; rolling temperature interval of recrystallization zone: 980-1120 ℃, and the total rolling reduction rate of the recrystallization zone is more than or equal to 40 percent; rolling temperature interval of non-recrystallization zone: the initial rolling temperature of finish rolling is 840-960 ℃, the rolling total reduction rate of an unrecrystallized area is more than or equal to 60%, and the final rolling temperature interval is as follows: 720-840 ℃; after rolling, accelerated cooling is adopted, the cooling speed is more than or equal to 9 ℃/s, and the final cooling temperature is as follows: 360-470 ℃. The yield strength of the steel plate produced by the manufacturing method is more than or equal to 550MPa, the tensile strength is more than or equal to 670MPa, the non-proportional elongation A50mm is more than or equal to 20 percent, the longitudinal impact energy at the temperature of minus 20 ℃ is more than or equal to 100J, the longitudinal low-temperature impact energy at the temperature of minus 40 ℃ is more than or equal to 47J, and the metallographic structure is low-carbon bainite.
Description
Technical Field
The invention relates to the technical field of ferrous metallurgy, in particular to low-cost boron-containing non-quenched and tempered 700MPa high-strength steel and a manufacturing method thereof.
Background
In 2005, the popularization of the domestic TMCP process, domestic mainstream steel mills all start to trial produce non-quenched and tempered high-tensile strength steel with the tensile strength of 700MPa grade by adopting the TMCP process, but because the process equipment of each production plant is different from the understanding direction of materials, the process and the method for producing the non-quenched and tempered high-tensile strength steel with the tensile strength of 700MPa grade by each steel enterprise are different. The company depends on the self technology, fully applies the microalloy technology on steel materials, reasonably controls the contents of [ N ], [ O ] and [ H ] in steel, regulates and controls the proportion of Mn-B which is a main hardenability element, fully exerts the effect of B element, adopts a full-flow grain refining production process to manufacture low-cost boron-containing non-quenched and tempered 700MPa grade high-strength steel, realizes non-preheating welding and effectively promotes the production of high-strength steel and the development of downstream industries.
Disclosure of Invention
The invention aims to provide low-cost boron-containing non-quenched and tempered 700MPa high-strength steel and a manufacturing method thereof, wherein the proportion of C, Mn and B in the steel is adjusted by controlling [ N ], [ O ] and [ H ] in molten steel, the elements of C, Mn and B are fully exerted without adding noble metals of Mo, Cr, Ni and Cu, and the non-quenched and tempered 700MPa high-strength low-alloy steel with good low-temperature toughness is obtained.
In order to achieve the purpose, the invention adopts the technical scheme that:
a low-cost boron-containing non-quenched and tempered 700MPa high-strength steel comprises the following chemical components in percentage by weight: c: 0.05-0.09%, Si: 0.12-0.60%, Mn: 1.55-1.85%, P is less than or equal to 0.020%, S is less than or equal to 0.010%, and Nb: 0.015 to 0.060%, Alt: 0.010-0.060%, B: 0.0008-0.0025%, Ti: 0.008 to 0.020 percent, less than or equal to 0.0060 percent of N, less than or equal to 0.0030 percent of O, less than or equal to 0.0002 percent of H, less than or equal to 0.15 percent of Cr, less than or equal to 0.08 percent of Mo, and the weight percentage of Ni: less than or equal to 0.15 percent, less than or equal to 0.15 percent of Cu, and the balance of Fe and inevitable impurities.
Further, the low-cost boron-containing non-quenched and tempered 700MPa high-strength steel comprises the following chemical components in percentage by weight: c: 0.06-0.07%, Si: 0.24-0.25%, Mn: 1.67-1.81%, P: 0.010-0.011%, S: 0.001%, Nb: 0.045-0.053%, Alt: 0.028-0.031%, B: 0.0016-0.0019%, Ti: 0.017%, N: 0.0045 percent, less than or equal to 0.0030 percent of O, less than or equal to 0.0002 percent of H, and the balance of Fe and inevitable impurities.
A manufacturing method of low-cost boron-containing non-quenched and tempered 700MPa high-strength steel comprises molten iron pretreatment, top and bottom combined blown converter, LF refining, VD vacuum refining, slab continuous casting and steckel mill rolling; wherein the content of the first and second substances,
the molten iron pretreatment: the S content of the molten iron is more than or equal to 0.040 percent, the molten iron pretreatment process is adopted for desulfurization, and the S content is controlled to be less than or equal to 0.010 percent;
oxygen blowing and converting for 14-16 min by the top-bottom combined blowing converter, wherein molten steel P is less than or equal to 0.015%, S is less than or equal to 0.020%, and O is less than or equal to 0.06% during tapping;
and in the LF refining and VD vacuum refining treatment, the temperature and the components of molten steel meet the requirements of continuous casting and target components, wherein the gas: n is less than or equal to 0.0060 percent, O is less than or equal to 0.0030 percent, and H is less than or equal to 0.0002 percent;
the continuous casting of the plate blank adopts the whole-process protective casting, the fluctuation of the drawing speed is +/-0.05 m/min, the fluctuation of the steel liquid level of a cleaner is +/-3 mm, and the superheat degree of molten steel is controlled at 10-25 ℃; the low segregation B of the casting blank is below grade 1.5, and the porosity is below grade 1.5.
Further, the steckel mill rolling comprises the following steps:
heating temperature of the plate blank: 1200-1280 ℃;
rolling temperature interval of recrystallization zone: 980-1120 ℃, the rolling pass reduction rate of the recrystallization zone is more than or equal to 15%, and the rolling total reduction rate of the recrystallization zone is more than or equal to 40%;
③ rolling temperature interval of non-recrystallization zone: the initial rolling temperature of finish rolling is 840-960 ℃, the rolling total reduction rate of an unrecrystallized area is more than or equal to 60%, and the final rolling temperature interval is as follows: 720-840 ℃;
fourthly, after rolling, accelerated cooling is adopted, the cooling speed is more than or equal to 9 ℃/s, and the final cooling temperature is as follows: 360-470 ℃.
Furthermore, the yield strength of the steel plate produced by the manufacturing method is more than or equal to 550MPa, the tensile strength is more than or equal to 670MPa, the non-proportional elongation A50mm is more than or equal to 20 percent, the longitudinal impact energy at the temperature of minus 20 ℃ is more than or equal to 100J, the longitudinal low-temperature impact energy at the temperature of minus 40 ℃ is more than or equal to 47J, and the metallographic structure is low-carbon bainite.
Compared with the prior art, the invention has the beneficial effects that:
1. the steel does not contain precious metals Mo, Cr, Ni and Cu, fully plays the role of C, Mn and B elements, obtains non-quenched and tempered 700MPa grade high-strength low-alloy steel with good low-temperature toughness, and reduces the cost.
2. The yield strength of the steel plate produced by the manufacturing method is more than or equal to 550MPa, the tensile strength is more than or equal to 670MPa, the non-proportional elongation A50mm is more than or equal to 20 percent, the longitudinal impact energy at the temperature of minus 20 ℃ is more than or equal to 100J, the longitudinal low-temperature impact energy at the temperature of minus 40 ℃ is more than or equal to 47J, and the non-preheating welding is realized.
Detailed Description
The technical solutions and effects of the present invention will be further described with reference to specific examples, but the scope of the present invention is not limited thereto.
Example 1
The present invention will be further described below by taking as an example the process of obtaining low cost boron-containing non-quenched and tempered 700MPa high strength steel of 30mm by regulating the ratio of the main hardenability element Mn-B in the Steckel mill production line of this company.
In the embodiment, the non-quenched and tempered steel comprises the following components in percentage by weight: c: 0.06%, Si: 0.25%, Mn: 1.81%, P: 0.010%, S: 0.001%, Nb: 0.053%, Alt: 0.028%, B: 0.0016%, Ti: 0.017%, N: 0.0045%, the balance being Fe and unavoidable impurities.
The production process route of the quenched and tempered steel comprises molten iron pretreatment, top and bottom combined blown converter, LF refining, VD degassing refining, wide slab continuous casting and steckel mill rolling. Wherein the content of S in the molten iron is controlled to be less than or equal to 0.010 percent through pretreatment; blowing oxygen and converting for 15min by a top-bottom combined blown converter, wherein molten steel P is less than or equal to 0.015 percent, S is less than or equal to 0.020 percent, and O is less than or equal to 0.06 percent during tapping; LF refining and VD vacuum refining treatment, molten steel temperature and composition meet continuous casting and target composition requirement, wherein gas: n: 0.0045%, O: 0.0018%, H: 0.00012 percent; the continuous casting of the wide plate blank adopts the whole-process protective casting, the fluctuation of the drawing speed is +/-0.05 m/min, the fluctuation of the steel liquid level of a cleaner is +/-3 mm, and the superheat degree of molten steel is controlled at 10-25 ℃; the low segregation B of the casting blank is below grade 1.5, and the porosity is below grade 1.5.
See table 1 for the steckel mill rolling process schedule. The method specifically comprises the following steps: the reheating temperature of the plate blank is 1230 ℃, the furnace time is 135min, the rolling pass and the accumulated reduction rate of a recrystallization region and a non-recrystallization region are shown in a table 2, the initial rolling temperature of the recrystallization region is 1080 ℃, the final rolling temperature of the recrystallization region is 1072 ℃, the reduction rate of the rolling pass of the recrystallization region is more than or equal to 15 percent (at least one pass is achieved), and the total reduction rate of the rolling of the recrystallization region is 42 percent; the initial rolling temperature of the non-recrystallization zone is 900 ℃, the final rolling temperature of the non-recrystallization zone is 831 ℃, and the rolling total reduction rate of the non-recrystallization zone is 66.1%; after rolling, accelerated cooling is adopted, the cooling speed is 24.3 ℃/s, and the final cooling temperature is 470 ℃.
Table 1 steckel mill rolling process schedule of example 1
TABLE 2 Steckel mill pass table for example 1
The steel sheets produced according to the procedure of this example had the performance indexes shown in Table 3.
TABLE 3 Performance index of the steel sheet manufactured in example 1
As can be seen from Table 3, the low-cost boron-containing non-quenched and tempered 700MPa high-strength steel which is produced by regulating the proportion of the main hardenability element Mn-B and does not contain Mo, Cr, Ni and Cu and is 30mm can meet the requirements of the product on strength, toughness, plasticity and the like, and has a certain margin.
Wherein Mn: 1.81%, B: 0.0016%, Ti: 0.017%, Alt: 0.028%, N: 0.0045 percent of the total Mn-B ratio, the quenching performance of the steel is very strong, the capacity of obtaining low-carbon bainite is very strong, meanwhile, because the steel contains Ti and Al, the N element of 0.0045 percent in the steel can be well fixed, the B is used for well deviating the grain boundary to fully exert the capacity of inhibiting ferrite nucleation and improving the quenching performance, and the corresponding structure can be obtained without adding Mo, Cr and Ni elements; and simultaneously O: 0.0018%, H: 0.00012 percent of steel water with good control level is clean, so that good steel quality is obtained, the final low-carbon bainite structure is refined by controlling rolling, cooling and refining, more effective grain boundaries are obtained, the whole grain refining control is realized, so that good impact toughness is obtained, and the impact energy at the low temperature of 40 ℃ below zero can reach more than 100J, which is one of the core technologies of the invention.
Example 2
The present invention will be further described below by taking as an example the process of obtaining low-cost boron-containing non-quenched and tempered 700MPa high strength steel of 20mm by regulating the ratio of the main hardenability element Mn-B in the steckel mill production line of this company.
In the embodiment, the non-quenched and tempered steel comprises the following components in percentage by weight: c: 0.07%, Si: 0.24%, Mn: 1.67%, P: 0.011%, S: 0.001%, Nb: 0.045%, Al: 0.031%, B: 0.0019%, Ti: 0.017%, N: 0.0045%, the balance being Fe and unavoidable impurities.
The production process route of the quenched and tempered steel comprises molten iron pretreatment, top and bottom combined blown converter, LF refining, VD degassing refining, wide slab continuous casting and steckel mill rolling. Wherein the content of S in the molten iron is controlled to be less than or equal to 0.010 percent through pretreatment; blowing oxygen and converting for 15min by a top-bottom combined blown converter, wherein molten steel P is less than or equal to 0.015 percent, S is less than or equal to 0.020 percent, and O is less than or equal to 0.06 percent during tapping; LF refining and VD vacuum refining treatment, molten steel temperature and composition meet continuous casting and target composition requirement, wherein gas: n: 0.0036%, O: 0.0022%, H: 0.00013 percent; the continuous casting of the wide plate blank adopts the whole-process protective casting, the stretching fluctuation is within +/-0.05 m/min, the steel liquid surface fluctuation of a cleaner is within +/-3 mm, and the superheat degree of molten steel is controlled to be 10-25 ℃; the low segregation B of the casting blank is below grade 1.5, and the porosity is below grade 1.5.
Wherein, the rolling process schedule of the steckel mill is shown in Table 4. The method specifically comprises the following steps: the reheating temperature of the plate blank is 1235 ℃, the furnace time is 136min, the rolling pass and the accumulated reduction rate of a recrystallization region and a non-recrystallization region are shown in Table 5, the initial rolling temperature of the recrystallization region is 1079 ℃, the final rolling temperature of the recrystallization region is 1060 ℃, the rolling pass reduction rate of the recrystallization region is more than or equal to 15 percent (at least one pass is achieved), and the total rolling reduction rate of the recrystallization region is 60.7 percent; the initial rolling temperature of the non-recrystallization zone is 908 ℃, the final rolling temperature of the non-recrystallization zone is 798 ℃, and the rolling total reduction rate of the non-recrystallization zone is 66.8%; after rolling, accelerated cooling is adopted, the cooling speed is 26.8 ℃/s, and the final cooling temperature is 465 ℃.
Table 4 steckel mill rolling process schedule of example 2
TABLE 5 Steckel mill pass table for example 2
The steel sheets produced according to the procedure of this example had the performance indexes shown in Table 6.
TABLE 6 Performance index of the steel sheet manufactured in example 2
As can be seen from Table 6, the low-cost boron-containing non-quenched and tempered 700MPa high-strength steel which is produced by regulating the proportion of the main hardenability element Mn-B and does not contain Mo, Cr, Ni and Cu and has the advantages of 20mm, capability of meeting the requirements of the product on strength, toughness, plasticity and the like and certain margin. Similarly, in this embodiment, Mn: 1.67%, B: 0.0019%, Ti: 0.017%, Alt: 0.031%, N: 0.0036 percent, and the Mn-B mixture ratio has strong steel quenching performance and strong capacity of obtaining low-carbon bainite, and simultaneously, because the steel contains Ti and Al, the N element of 0.0036 percent in the steel can be well fixed, the B is used for well performing segregation in the grain boundary to fully exert the capacity of inhibiting ferrite nucleation and improving the quenching performance, so that the corresponding structure can be obtained without adding Mo, Cr and Ni elements; and simultaneously O: 0.0022%, H: the control level of 0.00013 percent is good, the molten steel is clean, so that good steel quality is obtained, the final low-carbon bainite structure is refined by controlling rolling, cooling and refining, more effective crystal boundaries are obtained, the whole-process grain refining control is realized, so that good impact toughness is obtained, and the impact energy at the low temperature of-40 ℃ can reach more than 100J.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (4)
1. The low-cost boron-containing non-quenched and tempered 700MPa high-strength steel is characterized by comprising the following chemical components in percentage by weight: c: 0.05-0.09%, Si: 0.12-0.60%, Mn: 1.55-1.85%, P is less than or equal to 0.020%, S is less than or equal to 0.010%, and Nb: 0.015 to 0.060%, Alt: 0.010-0.060%, B: 0.0008-0.0025%, Ti: 0.008 to 0.020 percent, less than or equal to 0.0060 percent of N, less than or equal to 0.0030 percent of O, less than or equal to 0.0002 percent of H, less than or equal to 0.15 percent of Cr, less than or equal to 0.08 percent of Mo, and the weight percentage of Ni: less than or equal to 0.15 percent, less than or equal to 0.15 percent of Cu, and the balance of Fe and inevitable impurities.
2. A manufacturing approach of the boron-containing non-quenched and tempered 700MPa high strength steel of low cost, wherein the manufacturing approach includes the hot metal pretreatment, top and bottom combined blown converter, LF refining, VD vacuum refining, slab casting, steckel mill rolling; wherein the content of the first and second substances,
the molten iron pretreatment: the S content of the molten iron is more than or equal to 0.040 percent, the molten iron pretreatment process is adopted for desulfurization, and the S content is controlled to be less than or equal to 0.010 percent;
oxygen blowing and converting for 14-16 min by the top-bottom combined blowing converter, wherein molten steel P is less than or equal to 0.015%, S is less than or equal to 0.020%, and O is less than or equal to 0.06% during tapping;
and in the LF refining and VD vacuum refining treatment, the temperature and the components of molten steel meet the requirements of continuous casting and target components, wherein the gas: n is less than or equal to 0.0060 percent, O is less than or equal to 0.0030 percent, and H is less than or equal to 0.0002 percent;
the continuous casting of the plate blank adopts the whole-process protective casting, the fluctuation of the drawing speed is +/-0.05 m/min, the fluctuation of the steel liquid level of a cleaner is +/-3 mm, and the superheat degree of molten steel is controlled at 10-25 ℃; the low segregation B of the casting blank is below grade 1.5, and the porosity is below grade 1.5.
3. The method of manufacturing a low cost boron containing non-quenched and tempered 700MPa high strength steel of claim 2 wherein the steckel mill rolling comprises the steps of:
heating temperature of the plate blank: 1200-1280 ℃;
rolling temperature interval of recrystallization zone: 980-1120 ℃, the rolling pass reduction rate of the recrystallization zone is more than or equal to 15%, and the rolling total reduction rate of the recrystallization zone is more than or equal to 40%;
③ rolling temperature interval of non-recrystallization zone: the initial rolling temperature of finish rolling is 840-960 ℃, the rolling total reduction rate of an unrecrystallized area is more than or equal to 60%, and the final rolling temperature interval is as follows: 720-840 ℃;
fourthly, after rolling, accelerated cooling is adopted, the cooling speed is more than or equal to 9 ℃/s, and the final cooling temperature is as follows: 360-470 ℃.
4. The method for manufacturing low-cost boron-containing non-quenched and tempered 700MPa high-strength steel according to claim 2, wherein the yield strength of the steel plate produced by the method is not less than 550MPa, the tensile strength is not less than 670MPa, the non-proportional elongation A50mm is not less than 20%, the longitudinal impact energy at-20 ℃ is not less than 100J, the longitudinal low-temperature impact energy at-40 ℃ is not less than 47J, and the metallographic structure is low-carbon bainite.
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| CN113430460A (en) * | 2021-06-19 | 2021-09-24 | 宝钢湛江钢铁有限公司 | Low-cost high-strength non-quenched and tempered steel plate with yield strength of 690MPa and manufacturing method thereof |
| CN114480962A (en) * | 2021-12-24 | 2022-05-13 | 安阳钢铁集团有限责任公司 | Steel for 620 MPa-grade coal mine hydraulic support and manufacturing method thereof |
| CN114480958A (en) * | 2021-12-24 | 2022-05-13 | 安阳钢铁集团有限责任公司 | Low-cost molybdenum-free non-quenched and tempered 800MPa high-strength steel and manufacturing method thereof |
| CN114480961A (en) * | 2021-12-24 | 2022-05-13 | 安阳钢铁集团有限责任公司 | 620MPa grade high-strength steel with cold crack sensitivity coefficient less than or equal to 0.19 and production method thereof |
| CN114959515A (en) * | 2022-04-24 | 2022-08-30 | 安阳钢铁股份有限公司 | 890 MPa-level high-strength steel with low cold crack sensitivity coefficient and production method thereof |
| CN115011868A (en) * | 2022-04-22 | 2022-09-06 | 安阳钢铁股份有限公司 | Low-cost molybdenum-free controlled cooling process produced Q890 high-strength steel and manufacturing method thereof |
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| CN113373376A (en) * | 2021-05-27 | 2021-09-10 | 本钢板材股份有限公司 | Bainite non-quenched and tempered high-strength steel with tensile strength of more than or equal to 960MPa and manufacturing method thereof |
| CN113430460A (en) * | 2021-06-19 | 2021-09-24 | 宝钢湛江钢铁有限公司 | Low-cost high-strength non-quenched and tempered steel plate with yield strength of 690MPa and manufacturing method thereof |
| CN114480962A (en) * | 2021-12-24 | 2022-05-13 | 安阳钢铁集团有限责任公司 | Steel for 620 MPa-grade coal mine hydraulic support and manufacturing method thereof |
| CN114480958A (en) * | 2021-12-24 | 2022-05-13 | 安阳钢铁集团有限责任公司 | Low-cost molybdenum-free non-quenched and tempered 800MPa high-strength steel and manufacturing method thereof |
| CN114480961A (en) * | 2021-12-24 | 2022-05-13 | 安阳钢铁集团有限责任公司 | 620MPa grade high-strength steel with cold crack sensitivity coefficient less than or equal to 0.19 and production method thereof |
| CN114480961B (en) * | 2021-12-24 | 2023-03-10 | 安阳钢铁集团有限责任公司 | 620MPa grade high-strength steel with cold crack sensitivity coefficient less than or equal to 0.19 and production method thereof |
| CN114480962B (en) * | 2021-12-24 | 2023-03-10 | 安阳钢铁集团有限责任公司 | Steel for 620 MPa-grade coal mine hydraulic support and manufacturing method thereof |
| CN115011868A (en) * | 2022-04-22 | 2022-09-06 | 安阳钢铁股份有限公司 | Low-cost molybdenum-free controlled cooling process produced Q890 high-strength steel and manufacturing method thereof |
| CN114959515A (en) * | 2022-04-24 | 2022-08-30 | 安阳钢铁股份有限公司 | 890 MPa-level high-strength steel with low cold crack sensitivity coefficient and production method thereof |
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