CN113106208A - Method for improving performance uniformity of 780 MPa-grade galvanized dual-phase steel - Google Patents
Method for improving performance uniformity of 780 MPa-grade galvanized dual-phase steel Download PDFInfo
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- 229910000885 Dual-phase steel Inorganic materials 0.000 title claims abstract description 56
- 238000000034 method Methods 0.000 title claims abstract description 30
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 89
- 239000010959 steel Substances 0.000 claims abstract description 89
- 238000000137 annealing Methods 0.000 claims abstract description 53
- 238000010583 slow cooling Methods 0.000 claims abstract description 50
- 238000002791 soaking Methods 0.000 claims abstract description 49
- 238000010438 heat treatment Methods 0.000 claims abstract description 46
- 238000001816 cooling Methods 0.000 claims abstract description 11
- 239000000126 substance Substances 0.000 claims description 11
- 239000012535 impurity Substances 0.000 claims description 3
- 229910052804 chromium Inorganic materials 0.000 claims description 2
- 229910052750 molybdenum Inorganic materials 0.000 claims description 2
- 230000008859 change Effects 0.000 abstract description 5
- 230000014759 maintenance of location Effects 0.000 description 6
- 230000006872 improvement Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005246 galvanizing Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000013441 quality evaluation Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
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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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
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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
- C21D11/00—Process control or regulation for heat treatments
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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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
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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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium 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
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- 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
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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
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium 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
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
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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
- C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
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Abstract
The invention discloses a method for improving the performance uniformity of 780 MPa-grade galvanized dual-phase steel, which comprises the following steps: (1) and (3) controlling the temperature of the heating second stage: controlling the temperature of the strip steel at 750-780 ℃ in the heating second section, and keeping the strip steel for 1-2 min; (2) temperature control of the soaking section: controlling the temperature of the strip steel in a soaking section at 750-780 ℃ and keeping for 1-2 min; (3) controlling the outlet temperature of the slow cooling section: the outlet temperature of the slow cooling section is controlled to be 660-700 ℃, and the cooling speed of the slow cooling section is controlled to be 10-20 ℃/s; (4) controlling the speed of the strip steel in the continuous annealing furnace: the speed of the strip steel in the continuous annealing furnace is controlled to be 80-120 m/min. According to the invention, the mechanical property uniformity is improved by adjusting the phase change degree of the microstructure, the local property fluctuation range is reduced, and the mechanical property stability in the length direction of the strip steel can be effectively improved.
Description
Technical Field
The invention belongs to the technical field of metallurgy, and particularly relates to a method for improving the performance uniformity of 780 MPa-grade galvanized dual-phase steel.
Background
When 780 MPa-grade ultrahigh-strength dual-phase steel strip is produced by a continuous hot galvanizing production line, the fluctuation range of the local mechanical property of the steel strip is large under the influence of the temperature fluctuation of a heating furnace, and the performance difference of the head, the middle and the tail of the whole strip steel strip is sometimes as high as more than 40 MPa. The mechanical property difference in the length direction of the steel coil not only influences the objectivity of product quality evaluation, but also influences the use of downstream customers. In order to solve the phenomenon, the conventional method for stabilizing the temperature of the soaking section of the heating furnace is used for improving the phenomenon, but the effect is not obvious and the hysteresis is obvious.
By researching the influence of temperature control of the slow cooling section on the phase change of the microstructure and the improvement of mechanical properties, the mechanical properties of the galvanized dual-phase steel are analyzed, and the method for improving the performance uniformity of 780 MPa-grade galvanized dual-phase steel has important economic and social benefits.
Disclosure of Invention
The invention aims to provide a method for improving the performance uniformity of 780 MPa-grade galvanized dual-phase steel. The invention adjusts the phase change degree of the microstructure by comprehensively matching the temperatures of the heating two-section, the soaking section and the slow cooling section, improves the fluctuation of the local mechanical property of the 780MPa galvanized dual-phase steel coil in the length direction, and improves the stability of the mechanical property of the whole coil of strip steel.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a method for improving the performance uniformity of 780MPa grade galvanized dual-phase steel, comprising the following steps:
(1) controlling the temperature of the heating second section of the continuous annealing furnace: controlling the temperature of the strip steel at 750-780 ℃ in the second heating section, and keeping the strip steel at the second heating section for 1-2 min;
(2) controlling the temperature of the soaking section of the continuous annealing furnace: controlling the temperature of the strip steel in the soaking section at 750-780 ℃, and keeping the strip steel in the soaking section for 1-2 min;
(3) controlling the temperature of an outlet of a slow cooling section of the continuous annealing furnace: the outlet temperature of the slow cooling section is controlled to be 660-700 ℃, and the cooling speed of the slow cooling section is controlled to be 10-20 ℃/s;
(4) controlling the speed of the strip steel in the continuous annealing furnace: the speed of the strip steel in the continuous annealing furnace is controlled to be 80-120 m/min.
The galvanized dual-phase steel comprises the following chemical components in percentage by mass: c: 0.07-0.10%, Si is less than or equal to 0.12%, Mn: 1.70-2.10%, S is less than or equal to 0.012%, P is less than or equal to 0.020%, Cr: 0.20-0.35%, N is less than or equal to 0.0070%, Nb: 0.013-0.030%, Ti: 0.010 to 0.025%, Mo: 0.15-0.25%, B: 0.0010-0.0025%, and the balance of Fe and inevitable impurities.
The control target of the C content of the galvanized dual-phase steel is 0.08%, the C content of the steel coil is reduced by 0.01%, and the temperature of the second heating section and the soaking section is increased by 10 ℃; when the content of C in the steel coil is increased by 0.01 percent, the temperature of the heating second section and the soaking section is reduced by 10 ℃; the temperature adjustment is based on the temperature measured by a pyrometer, and the temperature adjustment range is 750-780 ℃.
The target temperatures of the heating two-stage section and the soaking section are 765-775 ℃.
The target temperature of the slow cooling section of the strip steel is 675-685 ℃.
When the target temperature fluctuation of the heating two-stage section is +/-10 ℃, the outlet temperatures of the soaking section and the slow cooling section are not adjusted.
The initial value of the slow cooling temperature is set to be 690 ℃, and when the actual temperature of the strip steel in the soaking section is 5-10 ℃ higher than the target temperature, the temperature of the strip steel at the slow cooling outlet is 10 ℃ lower than the target temperature.
The initial value of the slow cooling temperature is set to be 690 ℃, and when the actual temperature of the strip steel in the soaking section is 5-10 ℃ lower than the target temperature, the temperature of the strip steel at the slow cooling outlet is 10 ℃ higher than the target temperature.
The 780 MPa-grade galvanized dual-phase steel produced by the method has the yield strength of 450-500 MPa and the tensile strength of 790-850 MPa.
The specification of 780MPa grade galvanized dual-phase steel produced by the method is as follows: the thickness is 0.8-2.5 mm, the width is 350-850 mm, and the length is 800-1200 m.
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: 1. the invention utilizes the influence of temperature control of the heating second section, the soaking section and the slow cooling section on the phase change of the microstructure and the improvement of mechanical properties, adjusts the phase change degree of the microstructure by comprehensively matching the temperatures of the heating second section, the soaking section and the slow cooling section, further improves the uniformity of the mechanical properties, reduces the local property fluctuation range, can effectively improve the stability of the mechanical properties of the strip steel in the length direction, reduces the local property fluctuation of a 780MPa grade galvanized dual-phase steel coil in the length direction, and ensures that the yield strength fluctuation range of the head, the middle and the tail of the whole coil of the strip steel is less than or equal to 15MPa and the tensile strength fluctuation range is less than or equal to 20 MPa. 2. The 780 MPa-grade galvanized dual-phase steel produced by the invention has the following properties: the yield strength is 450-500 MPa, and the tensile strength is 790-850 MPa.
Drawings
FIG. 1 is a schematic diagram of a key process of 780MPa grade galvanized dual-phase steel continuous annealing;
wherein, 1-heating two sections, 2-soaking section and 3-slow cooling section.
Detailed Description
The invention is described in further detail below with reference to the figures and specific examples.
Example 1
The 780MPa grade galvanized dual-phase steel of the embodiment has the chemical components and the mass percentage content shown in the table 9, and the specification is as follows: thickness 1.8mm, width 1300mm, length 1200 m.
The method for improving the performance uniformity of 780 MPa-grade galvanized dual-phase steel comprises the following steps:
(1) controlling the temperature of the heating second section of the continuous annealing furnace: controlling the temperature of the strip steel at the second heating section at 765 ℃, wherein the retention time of the strip steel at the second heating section is 1.2 min;
(2) controlling the temperature of the soaking section of the continuous annealing furnace: controlling the temperature of the strip steel in the soaking section at 775 ℃, and keeping the strip steel in the soaking section for 1.5 min;
(3) controlling the temperature of an outlet of a slow cooling section of the continuous annealing furnace: the temperature of an outlet of the slow cooling section is controlled at 685 ℃, and the cooling speed of the slow cooling section is controlled at 18 ℃/s;
(4) controlling the speed of the strip steel in the continuous annealing furnace: the speed of the strip steel in the continuous annealing furnace is controlled at 95 m/min.
This example 780MPa grade galvanized dual-phase steel performance: the yield strength is 480MPa, the tensile strength is 820MPa, and the fluctuation of the head, middle and tail properties is shown in Table 1.
TABLE 1 mechanical Properties of the strip steels
Example 2
The 780 MPa-grade galvanized dual-phase steel of the embodiment has the chemical components and the mass percentage content shown in the table 1, and the specification is as follows: thickness 1.2mm, width 1200mm, length 1050 m.
The method for improving the performance uniformity of 780 MPa-grade galvanized dual-phase steel comprises the following steps:
(1) controlling the temperature of the heating second section of the continuous annealing furnace: the temperature of the strip steel in the heating second section is controlled to be 775 ℃, and the retention time of the strip steel in the heating second section is 1.4 min;
(2) controlling the temperature of the soaking section of the continuous annealing furnace: controlling the temperature of the strip steel in the soaking section at 765 ℃, and keeping the strip steel in the soaking section for 1.7 min;
(3) controlling the temperature of an outlet of a slow cooling section of the continuous annealing furnace: the temperature of the outlet of the slow cooling section is controlled at 675 ℃, and the cooling speed of the slow cooling section is controlled at 15 ℃/s;
(4) controlling the speed of the strip steel in the continuous annealing furnace: the speed of the strip steel in the continuous annealing furnace is controlled at 108 m/min.
This example 780MPa grade galvanized dual-phase steel performance: the yield strength is 495MPa, the tensile strength is 830MPa, and the fluctuation of the head, middle and tail properties is shown in Table 2.
TABLE 2 mechanical properties of the strip steel
Example 3
The 780 MPa-grade galvanized dual-phase steel of the embodiment has the chemical components and the mass percentage content shown in the table 1, and the specification is as follows: thickness 2.0mm, width 1300mm, length 1050 m.
The method for improving the performance uniformity of 780 MPa-grade galvanized dual-phase steel comprises the following steps:
(1) controlling the temperature of the heating second section of the continuous annealing furnace: the temperature of the strip steel in the second heating section is controlled to be 780 ℃, and the retention time of the strip steel in the second heating section is 1.3 min;
(2) controlling the temperature of the soaking section of the continuous annealing furnace: controlling the temperature of the strip steel in the soaking section at 780 ℃, and keeping the strip steel in the soaking section for 1.1 min;
(3) controlling the temperature of an outlet of a slow cooling section of the continuous annealing furnace: the outlet temperature of the slow cooling section is controlled to be 665 ℃, and the cooling speed of the slow cooling section is controlled to be 12 ℃/s;
(4) controlling the speed of the strip steel in the continuous annealing furnace: the speed of the strip steel in the continuous annealing furnace is controlled at 85 m/min.
This example 780MPa grade galvanized dual-phase steel performance: the yield strength is 460MPa, the tensile strength is 810MPa, and the fluctuation of the head, middle and tail properties is shown in Table 3.
TABLE 3 mechanical Properties of the strip steels
Example 4
The 780 MPa-grade galvanized dual-phase steel of the embodiment has the chemical components and the mass percentage content shown in the table 1, and the specification is as follows: thickness 1.5mm, width 1150mm, length 900 m.
The method for improving the performance uniformity of 780 MPa-grade galvanized dual-phase steel comprises the following steps:
(1) controlling the temperature of the heating second section of the continuous annealing furnace: the temperature of the strip steel in the heating second section is controlled at 760 ℃, and the retention time of the strip steel in the heating second section is 1.8 min;
(2) controlling the temperature of the soaking section of the continuous annealing furnace: controlling the temperature of the strip steel in the soaking section at 762 ℃, and keeping the strip steel in the soaking section for 1.7 min;
(3) controlling the temperature of an outlet of a slow cooling section of the continuous annealing furnace: the outlet temperature of the slow cooling section is controlled at 690 ℃, and the cooling speed of the slow cooling section is controlled at 16 ℃/s;
(4) controlling the speed of the strip steel in the continuous annealing furnace: the speed of the strip steel in the continuous annealing furnace is controlled at 105 m/min.
This example 780MPa grade galvanized dual-phase steel performance: the yield strength was 455MPa, the tensile strength was 796MPa, and the fluctuation of the properties at the head, middle and tail are shown in Table 4.
TABLE 4 mechanical properties of the strip steel
Example 5
The 780 MPa-grade galvanized dual-phase steel of the embodiment has the chemical components and the mass percentage content shown in the table 1, and the specification is as follows: thickness 2.0mm, width 1200mm, length 1100 m.
The method for improving the performance uniformity of 780 MPa-grade galvanized dual-phase steel comprises the following steps:
(1) controlling the temperature of the heating second section of the continuous annealing furnace: controlling the temperature of the strip steel at 750 ℃ in the heating second stage, wherein the retention time of the strip steel in the heating second stage is 1.9 min;
(2) controlling the temperature of the soaking section of the continuous annealing furnace: controlling the temperature of the strip steel in the soaking section at 750 ℃, and keeping the strip steel in the soaking section for 1.3 min;
(3) controlling the temperature of an outlet of a slow cooling section of the continuous annealing furnace: the temperature of the outlet of the slow cooling section is controlled at 700 ℃, and the cooling speed of the slow cooling section is controlled at 17 ℃/s;
(4) controlling the speed of the strip steel in the continuous annealing furnace: the speed of the strip steel in the continuous annealing furnace is controlled at 115 m/min.
This example 780MPa grade galvanized dual-phase steel performance: the yield strength is 470MPa, the tensile strength is 815MPa, and the fluctuation of the head, middle and tail properties is shown in Table 5.
TABLE 5 strip steel mechanical properties
Example 6
The 780 MPa-grade galvanized dual-phase steel of the embodiment has the chemical components and the mass percentage content shown in the table 1, and the specification is as follows: thickness 1.0mm, width 1000mm, length 1000 m.
The method for improving the performance uniformity of 780 MPa-grade galvanized dual-phase steel comprises the following steps:
(1) controlling the temperature of the heating second section of the continuous annealing furnace: controlling the temperature of the strip steel at 778 ℃ in the second heating section, and keeping the strip steel in the second heating section for 1.1 min;
(2) controlling the temperature of the soaking section of the continuous annealing furnace: controlling the temperature of the strip steel in the soaking section at 777 ℃, and keeping the strip steel in the soaking section for 1.6 min;
(3) controlling the temperature of an outlet of a slow cooling section of the continuous annealing furnace: the temperature of the outlet of the slow cooling section is controlled to be 660 ℃, and the cooling speed of the slow cooling section is controlled to be 11 ℃/s;
(4) controlling the speed of the strip steel in the continuous annealing furnace: the speed of the strip steel in the continuous annealing furnace is controlled at 112 m/min.
This example 780MPa grade galvanized dual-phase steel performance: the yield strength was 493MPa, the tensile strength was 827MPa, and the head, middle and tail properties fluctuate as shown in Table 6.
TABLE 6 mechanical Properties of the strip
Example 7
The 780 MPa-grade galvanized dual-phase steel of the embodiment has the chemical components and the mass percentage content shown in the table 1, and the specification is as follows: the thickness is 2.5mm, the width is 1350mm and the length is 1200 m.
The method for improving the performance uniformity of 780 MPa-grade galvanized dual-phase steel comprises the following steps:
(1) controlling the temperature of the heating second section of the continuous annealing furnace: the temperature of the strip steel in the heating second section is controlled at 770 ℃, and the retention time of the strip steel in the heating second section is 1.0 min;
(2) controlling the temperature of the soaking section of the continuous annealing furnace: controlling the temperature of the strip steel in the soaking section at 768 ℃, and keeping the strip steel in the soaking section for 2.0 min;
(3) controlling the temperature of an outlet of a slow cooling section of the continuous annealing furnace: the outlet temperature of the slow cooling section is controlled at 682 ℃, and the cooling speed of the slow cooling section is controlled at 10 ℃/s;
(4) controlling the speed of the strip steel in the continuous annealing furnace: the speed of the strip steel in the continuous annealing furnace is controlled at 120 m/min.
This example 780MPa grade galvanized dual-phase steel performance: the yield strength is 469MPa, the tensile strength is 817MPa, and the fluctuation of the head, middle and tail properties is shown in Table 7.
TABLE 7 strip steel mechanical properties
Example 8
The 780 MPa-grade galvanized dual-phase steel of the embodiment has the chemical components and the mass percentage content shown in the table 1, and the specification is as follows: the thickness is 0.8mm, the width is 850mm, and the length is 800 m.
The method for improving the performance uniformity of 780 MPa-grade galvanized dual-phase steel comprises the following steps:
(1) controlling the temperature of the heating second section of the continuous annealing furnace: controlling the temperature of the strip steel at 767 ℃ in the second heating section, and keeping the residence time of the strip steel in the second heating section for 2.0 min;
(2) controlling the temperature of the soaking section of the continuous annealing furnace: controlling the temperature of the strip steel in the soaking section at 772 ℃, and keeping the strip steel in the soaking section for 1.0 min;
(3) controlling the temperature of an outlet of a slow cooling section of the continuous annealing furnace: the outlet temperature of the slow cooling section is controlled at 682 ℃, and the cooling speed of the slow cooling section is controlled at 20 ℃/s;
(4) controlling the speed of the strip steel in the continuous annealing furnace: the speed of the strip steel in the continuous annealing furnace is controlled at 80 m/min.
This example 780MPa grade galvanized dual-phase steel performance: the yield strength was 479MPa, the tensile strength was 822MPa, and the fluctuation of the properties at the head, middle and tail are shown in Table 8.
TABLE 8 mechanical Properties of the strip
TABLE 9 examples 1-8780 MPa grade galvanized dual-phase steel chemical composition and mass percent (%)
The balance of the ingredients in table 9 is Fe and inevitable impurities.
Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention as defined in the appended claims.
Claims (10)
1. A method for improving the performance uniformity of 780 MPa-grade galvanized dual-phase steel is characterized by comprising the following steps:
(1) controlling the temperature of the heating second section of the continuous annealing furnace: controlling the temperature of the strip steel at 750-780 ℃ in the second heating section, and keeping the strip steel at the second heating section for 1-2 min;
(2) controlling the temperature of the soaking section of the continuous annealing furnace: controlling the temperature of the strip steel in the soaking section at 750-780 ℃, and keeping the strip steel in the soaking section for 1-2 min;
(3) controlling the temperature of an outlet of a slow cooling section of the continuous annealing furnace: the outlet temperature of the slow cooling section is controlled to be 660-700 ℃, and the cooling speed of the slow cooling section is controlled to be 10-20 ℃/s;
(4) controlling the speed of the strip steel in the continuous annealing furnace: the speed of the strip steel in the continuous annealing furnace is controlled to be 80-120 m/min.
2. The method for improving the performance uniformity of 780MPa grade galvanized dual-phase steel according to claim 1, wherein the galvanized dual-phase steel comprises the following chemical components in percentage by mass: c: 0.07-0.10%, Si is less than or equal to 0.12%, Mn: 1.70-2.10%, S is less than or equal to 0.012%, P is less than or equal to 0.020%, Cr: 0.20-0.35%, N is less than or equal to 0.0070%, Nb: 0.013-0.030%, Ti: 0.010 to 0.025%, Mo: 0.15-0.25%, B: 0.0010-0.0025%, and the balance of Fe and inevitable impurities.
3. The method for improving the performance uniformity of 780MPa galvanized dual-phase steel according to claim 1, characterized in that the C content of the galvanized dual-phase steel is controlled to be 0.08%, the temperature of the heating second stage and the soaking stage is increased by 10 ℃ every time the C content of the steel coil is reduced by 0.01%; when the content of C in the steel coil is increased by 0.01 percent, the temperature of the heating second section and the soaking section is reduced by 10 ℃; the temperature adjustment is based on the temperature measured by a pyrometer, and the temperature adjustment range is 750-780 ℃.
4. The method for improving the performance uniformity of 780MPa galvanized dual-phase steel according to any one of claims 1 to 3, characterized in that the target temperatures of the heating two-stage section and the soaking section are 765-775 ℃.
5. The method for improving the performance uniformity of 780MPa grade galvanized dual-phase steel according to any one of claims 1 to 3, characterized in that the target temperature of the slow cooling section of the strip steel is 675-685 ℃.
6. The method for improving the performance uniformity of 780MPa grade galvanized dual-phase steel according to any one of claims 1-3, characterized in that when the target temperature fluctuation of the heating two-stage is +/-10 ℃, the outlet temperature of the soaking stage and the slow cooling stage is not adjusted.
7. The method for improving the performance uniformity of 780MPa galvanized dual-phase steel according to any one of claims 1 to 3, characterized in that the initial slow cooling temperature is set to be 690 ℃, and when the actual temperature of the strip at the soaking section is 5-10 ℃ higher than the target temperature, the temperature of the strip at the slow cooling outlet is 10 ℃ lower than the target temperature.
8. The method for improving the performance uniformity of 780MPa galvanized dual-phase steel according to any one of claims 1 to 3, characterized in that the initial slow cooling temperature is set to be 690 ℃, and when the actual temperature of the strip at the soaking section is 5-10 ℃ lower than the target temperature, the temperature of the strip at the slow cooling outlet is 10 ℃ higher than the target temperature.
9. The method for improving the performance uniformity of 780MPa galvanized dual-phase steel according to any one of claims 1 to 3, characterized in that the 780MPa galvanized dual-phase steel produced by the method has the yield strength of 450-500 MPa, the tensile strength of 790-850 MPa, the fluctuation range of the yield strength of the head, middle and tail of the whole coil of strip steel is less than or equal to 15MPa, and the fluctuation range of the tensile strength is less than or equal to 20 MPa.
10. The method for improving the performance uniformity of 780MPa grade galvanized dual-phase steel according to any one of claims 1-3, characterized in that the specification of the 780MPa grade galvanized dual-phase steel produced by the method is as follows: the thickness is 0.8-2.5 mm, the width is 850-1350 mm, and the length is 800-1200 m.
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| CN202110290916.5A CN113106208A (en) | 2021-03-18 | 2021-03-18 | Method for improving performance uniformity of 780 MPa-grade galvanized dual-phase steel |
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| WO2009125820A1 (en) * | 2008-04-09 | 2009-10-15 | 新日本製鐵株式会社 | PROCESS FOR PRODUCTION OF 780MPa-GRADE HIGH-TENSILE-STRENGTH STEEL PLATES EXCELLENT IN LOW-TEMPERATURE TOUGHNESS |
| JP2011032549A (en) * | 2009-08-04 | 2011-02-17 | Jfe Steel Corp | High-strength hot-dip galvanized steel strip with excellent moldability and less variation of material grade in steel strip, and method for production thereof |
| CN102719751A (en) * | 2011-03-29 | 2012-10-10 | 鞍钢股份有限公司 | High-strength cold-rolled hot-galvanized dual-phase steel plate and manufacture method thereof |
| CN103797135A (en) * | 2011-07-06 | 2014-05-14 | 新日铁住金株式会社 | Method for producing cold-rolled steel sheet |
| CN108517466A (en) * | 2018-05-17 | 2018-09-11 | 马鞍山钢铁股份有限公司 | A kind of tensile strength 780MPa grades of dual-phase steel plates and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2009125820A1 (en) * | 2008-04-09 | 2009-10-15 | 新日本製鐵株式会社 | PROCESS FOR PRODUCTION OF 780MPa-GRADE HIGH-TENSILE-STRENGTH STEEL PLATES EXCELLENT IN LOW-TEMPERATURE TOUGHNESS |
| JP2011032549A (en) * | 2009-08-04 | 2011-02-17 | Jfe Steel Corp | High-strength hot-dip galvanized steel strip with excellent moldability and less variation of material grade in steel strip, and method for production thereof |
| CN102719751A (en) * | 2011-03-29 | 2012-10-10 | 鞍钢股份有限公司 | High-strength cold-rolled hot-galvanized dual-phase steel plate and manufacture method thereof |
| CN103797135A (en) * | 2011-07-06 | 2014-05-14 | 新日铁住金株式会社 | Method for producing cold-rolled steel sheet |
| CN108517466A (en) * | 2018-05-17 | 2018-09-11 | 马鞍山钢铁股份有限公司 | A kind of tensile strength 780MPa grades of dual-phase steel plates and preparation method thereof |
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