CN113584410A - Production method of novel high-strength extra-thick FH500 steel plate for ocean engineering - Google Patents
Production method of novel high-strength extra-thick FH500 steel plate for ocean engineering 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
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- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
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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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/002—Bainite
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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
- C21D2211/005—Ferrite
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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
- C21D2211/009—Pearlite
Abstract
The invention relates to the technical field of medium-thickness steel plate production, in particular to a production method of a novel high-strength extra-thick FH500 steel plate for ocean engineering. The steel plate comprises the following chemical components in percentage by mass: c: 0.080 to 0.11, Si: 0.20 to 0.50, Mn: 1.45-1.60, P: 0.012 or less, S: less than or equal to 0.005, Cr: 0.5 to 1.00, Ni: 0.25 to 1.1, Nb: 0.030-0.050, V: 0.03 to 0.08, Mo: 0.35 to 0.95, Ti: 0.015-0.022, B is 0.0010-0.0020, Als: less than or equal to 0.050, and the balance of Fe and residual elements; the casting blank with the thickness of 300-450mm is adopted, and the finished steel plate with the thickness of 80-120mm is obtained through heating, controlled rolling and heap cooling, the steel plate structure mainly comprises lath bainite and contains a small amount of ferrite and pearlite, and all performance indexes are superior to the national standard. Compared with the traditional process, the invention shortens the whole production flow, is beneficial to reducing the cost and improving the enterprise benefit on the premise of ensuring the performance of the steel plate.
Description
Technical Field
The invention relates to the technical field of medium-thickness steel plate production, in particular to a production method of a novel high-strength extra-thick FH500 steel plate for ocean engineering.
Background
FH500 belongs to high yield strength ship plate steel in national standard GB/T712, and has the characteristics of high strength, good toughness, excellent low-temperature toughness, good processability and weldability, corrosion resistance and the like. With the development of large-scale, light-weight and energy-saving of ships and ocean platforms, the requirement on steel for maritime workers is higher and higher, steel plates with high strength, excellent toughness, weldability and super-thick specifications are required, some achievements are reported in the research and development of FH500 ship plates of related steel enterprises in recent years, related patents are also published, but FH500 ship plates produced by other steel enterprises at present are basically produced by adopting a quenching and tempering process, the production process is complex, the production period is long, and the production efficiency is low; in addition, even if part of the steel rabbet is produced by adopting a rolling process, only relatively thin steel plates can be produced due to the fact that the technical bottleneck cannot be broken through.
The patent with the publication number of CN108517463A discloses a high-ductility FH 500-grade ship plate steel and a preparation method thereof, wherein the content of a component C is low, and the difficulty in production operation is high; the production thickness of the steel plate is only 19-30 mm, and the requirement and the practical use of the existing extra-thick ship plate cannot be met.
The patents with publication numbers CN101781742B and CN109112429A disclose medium-thickness ship plate steel with ultra-high strength and excellent low-temperature impact toughness and a manufacturing method thereof, which can only produce thin steel plates with thicknesses of 18-40 mm and 50-80mm, and cannot meet the current demand and practical use of extra-thick ship plates.
The patent with publication number CN106756612A discloses a bainite/martensite/austenite high-toughness easy-welding ship plate steel and a manufacturing method thereof, wherein the production process of the ship plate steel needs quenching and tempering treatment, and the invention has the advantages of complex production process, long production period and low production efficiency.
The patent publication Nos. CN104911503B and CN102021489A also disclose a preparation method, but the production process of the invention needs to be modified, and the invention has the advantages of complex production process, long production period and low production efficiency.
Disclosure of Invention
In order to solve the technical defects, the invention aims to provide the production method of the novel high-strength extra-thick FH500 steel plate for ocean engineering, compared with the traditional process, the whole production flow is shortened, the cost is reduced and the enterprise benefit is improved on the premise of ensuring the performance of the steel plate.
In order to achieve the purpose, the invention adopts the technical scheme that: a production method of a novel high-strength extra-thick FH500 steel plate for ocean engineering is provided, wherein the thickness of the steel plate is 300-450mm, and the steel plate comprises the following chemical components in percentage by mass: 0.080-0.11% of C, 0.20-0.50% of Si, 1.45-1.60% of Mn, less than or equal to 0.012% of P, less than or equal to 0.005% of S, 0.5-1.00% of Cr, 0.25-1.1% of Ni, 0.030-0.050% of Nb, 0.03-0.08% of V, 0.35-0.95% of Mo, 0.015-0.022% of Ti, 0.0010-0.0020% of B, less than or equal to 0.050% of Als, and the balance of Fe and residual elements;
the steel plate mainly comprises bainite as a structure and a small amount of ferrite and pearlite, wherein the volume fraction of the bainite is 80-90%, the volume fraction of the ferrite is 5-10%, and the volume fraction of the pearlite is 5-10%;
the thickness of the steel plate is 80-120mm, the yield strength is 520-595 MPa, the tensile strength is 630-750 MPa, the elongation is 17% -25%, the longitudinal impact energy at the temperature of V-60 ℃ is 168-306J, and the transverse impact energy at the temperature of V-60 ℃ is 143-296J;
the production method of the steel plate comprises the following steps of molten iron pretreatment, converter smelting, LF refining, VD vacuum degassing, continuous casting and pouring, heating, rolling and heap cooling:
wherein in the heating process, the billet with the thickness of 300-;
in the rolling process, three-stage controlled rolling is carried out on a billet, the first stage is austenite recrystallization area rolling, a high-temperature, low-speed and large reduction process is adopted, the rolling temperature is controlled to be 1050-1200 ℃, the pass reduction is not less than 45mm, so that the rolling force reaches the core of the billet, on one hand, the recrystallization of the core of the casting blank is promoted, the foundation is laid for the grain refinement of the core, on the other hand, the deformation of the core of the billet is promoted, and the segregation and the defects of the core of the casting blank are greatly improved; the second stage is still rolling in an austenite recrystallization region, the rolling temperature is controlled to be 930-1000 ℃, the pass reduction is controlled according to 10-30mm, the rolling force reaches the thickness position of a casting blank 1/4, the deformation of the position 1/4 is promoted, and the aims of recrystallization at the position of a casting blank 1/4 and creating conditions for grain refinement are finally achieved, when the thickness of an intermediate blank reaches 1.5-2.0 times of the thickness of a finished product, the second stage rolling is finished, and the intermediate blank enters an IC device for rapid cooling; and when the temperature of the intermediate blank is 850-900 ℃, rolling in an austenite non-recrystallization region in the third stage is started, the accumulated reduction rate in the stages is more than or equal to 50%, and the final rolling temperature is 750-800 ℃, so that the effective area of austenite grain boundaries is increased, more nucleation points are provided for austenite transformation, and the effect of refining grains is achieved. After rolling, the steel plate enters ACC for cooling, the cooling speed is controlled to be 5-15 ℃/S, the temperature of red returning is controlled to be 500-600 ℃, crystal grains in the rolled steel plate can be prevented from growing up, impact toughness is affected, and the steel plate is guaranteed to have good strength and toughness;
in the heap cooling process, the steel plate is straightened, then the steel plate is off-line and is subjected to heap cooling, the heap cooling temperature is more than or equal to 350 ℃, and the heap cooling time is more than or equal to 24 hours, so that the steel plate with the thickness of 80-120mm is obtained. Through slow cooling, to avoid inside stress to too late release to produce the internal crack, further impel the inside harmful gas of steel sheet to spill over simultaneously.
The invention has the beneficial effects that:
according to the invention, the rolling temperature is controlled at 1050-1200 ℃ in the first stage, and the process of high temperature, low speed and high reduction is adopted, so that the rolling force can penetrate into the core part of the steel billet, the core part of the steel billet is promoted to deform at high temperature, the defects of loosening, shrinkage cavity and the like of the core part of the large-thickness casting blank can be overcome, the quality of the core part of the casting blank can be improved or enhanced, the problems of center loosening and segregation of the existing large-thickness casting blank for producing an extra-thick plate can be solved, and the guarantee is provided for producing the high-quality extra-thick high-strength ship plate in the aspect of rolling; on the other hand, the recrystallization of the core part of the casting blank is promoted, and a foundation is laid for the grain refinement of the core part;
rolling at a second stage at 930-1000 ℃ under a low reduction condition to enable the rolling force to reach the thickness position of a casting blank 1/4, so that the 1/4 position of a billet is deformed and recrystallized, and conditions are created for grain refinement of the 1/4 thickness position of the extra-thick plate;
through three-stage rolling, particularly the accurate control of the rolling reduction in the first two stages, the problem that flaw detection is unqualified due to the fact that defects such as center segregation, looseness and the like are easily generated when the continuous casting slab is produced by two-stage rolling is solved, and meanwhile, the problem that the mechanical property anisotropy of the extra-thick plate is large is greatly relieved; in addition, the production process of controlled rolling and stacking cooling is adopted, the conventional tempering process is omitted, the whole process flow is shortened, the cost is saved and the enterprise benefit is improved on the premise of ensuring the performance of the steel plate.
Detailed Description
The technical scheme of the novel high-strength extra-thick FH500 steel plate for ocean engineering comprises the following chemical components in percentage by mass (unit, wt%): c: 0.080 to 0.11, Si: 0.20 to 0.50, Mn: 1.45-1.60, P: 0.012 or less, S: less than or equal to 0.005, Cr: 0.5 to 1.00, Ni: 0.25 to 1.1, Nb: 0.030-0.050, V: 0.03 to 0.08, Mo: 0.35 to 0.95, Ti: 0.015-0.022, B: 0.0010-0.0020, Als: less than or equal to 0.050, and the balance of Fe and residual elements.
The production method adopted by the invention comprises the following steps: molten iron pretreatment, converter smelting, LF refining, VD vacuum degassing, continuous casting and pouring, heating, rolling and heap cooling,
firstly, a molten iron pretreatment process: the molten iron S is ensured to be less than or equal to 0.005 percent after lime is blown, stirred and desulfurized, and meanwhile, a heat preservation measure is made to avoid the too fast temperature drop;
② a converter smelting process: the S content of the molten iron entering the furnace is less than or equal to 0.005 percent, the P content is less than or equal to 0.030 percent, the temperature of the molten iron is more than or equal to 1290 ℃, high-quality scrap steel is prepared, slag forming materials are added, the slag forming alkalinity is controlled according to 2.5-4.0, the P content of the steel is less than or equal to 0.010 percent, and the slag amount in a steel ladle in the steel tapping process is controlled;
③ LF refining process: argon is blown in the whole refining process, the argon blowing intensity is adjusted timely according to specific conditions, the argon blowing effect is guaranteed, the refined slag charge is added to make white slag, meanwhile, the white slag holding time is guaranteed to be more than or equal to 20min, and the calcium wire is added after refining is finished;
VD refining technology: VD vacuum degree must reach below 67Pa, dwell time is more than or equal to 13min, argon is blown into steel after vacuum is finished, strength is based on that molten steel does not tumble, and a proper amount of covering agent is added after argon blowing is finished, so that the temperature of the molten steel is ensured;
and (6) continuous casting process: ensuring good condition of casting machine equipment before steel casting, wherein the superheat degree of a tundish is 15 +/-10 ℃, selecting a pulling speed according to a casting blank with the thickness of 300 plus or minus 450mm to ensure the requirement of the rolling compression ratio of the thick plate and the refining condition of internal tissues, starting electromagnetic stirring in the casting process, protecting casting in the whole process, and requiring that the cooling of a pile is more than or equal to 24 hours after the casting blank is off line;
heating process, wherein the temperature of the preheating section is 850-;
and the rolling process comprises the following steps: three-stage rolling is adopted, wherein the first stage is austenite recrystallization area rolling, a high-temperature, low-speed and large reduction process is adopted, the rolling temperature is controlled to be 1050-1200 ℃, the pass reduction is not less than 45mm, so that the rolling force reaches the core of a billet, on one hand, the recrystallization of the core of the casting blank is promoted, the foundation is laid for the grain refinement of the core, on the other hand, the deformation of the core of the billet is promoted, and the segregation and the defects of the core of the casting blank are greatly improved;
the second stage is still rolling in an austenite recrystallization region, the rolling temperature is controlled to be 930-1000 ℃, the pass reduction is controlled according to 10-30mm, the rolling force reaches the thickness position of a casting blank 1/4, the deformation of the position 1/4 is promoted, and the aims of recrystallization at the position of a casting blank 1/4 and creating conditions for grain refinement are finally achieved, when the thickness of an intermediate blank reaches 1.5-2.0 times of the thickness of a finished product, the second stage rolling is finished, and the intermediate blank enters an IC device for rapid cooling;
the third stage is rolling in an austenite non-recrystallization region, when the temperature of the intermediate blank is 850-900 ℃, the third stage rolling is started, the accumulated reduction rate of the stages is more than or equal to 50%, and the final rolling temperature is 750-800 ℃, so that the effective area of austenite grain boundaries is increased, more nucleation points are provided for refining austenite grains, and the effect of refining the grains is achieved.
In order to avoid the growth of crystal grains in the rolled steel plate and influence on impact toughness and ensure that the steel plate has good toughness and toughness matching, the steel plate is cooled by an online rapid cooling device after being rolled, the cooling speed is controlled to be 5-15 ℃/S, the temperature of red return is 500-600 ℃, and then the steel plate is sent to a straightening machine for straightening.
The process of cooling in heap: and (4) timely unloading and stacking for cooling after the steel plate is straightened, wherein the stacking temperature is more than or equal to 350 ℃, and the stacking time is more than or equal to 24 h. Through slow cooling, to avoid inside stress to too late release to produce the internal crack, further impel the inside harmful gas of steel sheet to spill over simultaneously.
Example 1:
firstly, molten steel is smelted according to the component design and cast into a casting blank with the thickness of 300-450mm, the temperature of the casting blank in a preheating section is 910 ℃, the temperature of a heating section is 1230 ℃, the temperature of a heat preservation section is 1210 ℃, the heat preservation time of the heat preservation section is 42min, the integral heating time is 11min/cm, and the chemical components and the weight percentage of the steel blank are shown in table 1.
Secondly, three-stage rolling is carried out on the heated casting blank, wherein the first-stage rolling temperature is 1170 ℃, two-stage large-reduction rolling is carried out, the reduction is 50mm, the thickness of the steel blank is changed from 300-450mm to 200-350 mm, and the final rolling temperature is 1050 ℃; the second stage is at the initial rolling temperature of 980 ℃, then three rolling passes are carried out, the pass reduction is 10mm, the thickness of the intermediate billet is 170-320 mm, the intermediate billet is cooled to 896 ℃ after entering the IC, the third stage is started, the rolling thicknesses are (according to the thickness of a casting blank of 300mm) 170-155 mm-140mm-125mm-110mm-100mm-90mm in sequence, the cumulative reduction rate is 60.31% (if the thickness of the casting blank is more than 300mm, the cumulative reduction rate is higher), the final rolling temperature is 795 ℃, and the ACC cooling is rapidly carried out after the rolling is finished;
thirdly, opening the group number by adjusting the collecting pipe after entering the ACC, controlling the cooling speed at 6 ℃/S and the temperature of returning red at 560 ℃, and quickly straightening after going out of the ACC;
fourthly, straightening the steel plate, inserting the steel plate off line, and performing stack cooling at the stack cooling temperature of 390 ℃ for 24 hours;
after the end of the cooling, the performance results of the steel plate sampling test are shown in table 2.
Example 2:
firstly, molten steel is smelted according to component design and cast into a casting blank with the thickness of 300-450mm, the temperature of the preheating section of the casting blank after the casting blank is put into a furnace is 860 ℃, the temperature of the heating section is 1240 ℃, the temperature of the heat preservation section is 1220 ℃, the heat preservation time of the heat preservation section is 48min, the integral heating time is 13min/cm, and the chemical components and the weight percentage of the steel blank are shown in table 1.
Secondly, three-stage rolling is carried out on the heated casting blank, the initial rolling temperature of the first stage is 1200 ℃, two-stage large reduction rolling is carried out, the reduction is 50mm, the thickness of the steel blank is changed from 300-450mm to 200-350 mm, and the final rolling temperature is 1100 ℃; the second stage is at the start rolling temperature of 950 ℃, two times of rolling are carried out, the pass reduction is 12mm, the thickness of the intermediate billet is 176-326 mm, the intermediate billet is cooled to 870 ℃ after entering the IC, the third stage of rolling is started, the rolling thickness is (according to the thickness of a casting blank, 300mm) in turn from 176mm-155mm-135mm-120mm-110mm-100mm, the cumulative reduction rate is 53.34% (if the thickness of the casting blank is more than 300mm, the cumulative reduction rate is higher), the final rolling temperature is 780 ℃, and the ACC cooling is carried out after the rolling is finished;
thirdly, opening the group number by adjusting the collecting pipe after entering the ACC, controlling the cooling speed at 8 ℃/S and the temperature of returning red at 540 ℃, and quickly straightening after going out of the ACC;
fourthly, straightening the steel plate, inserting the steel plate, and performing stack cooling at the stack cooling temperature of 400 ℃ for 36 hours;
after the end of the cooling, the performance results of the steel plate sampling test are shown in table 2.
Example 3:
firstly, molten steel is smelted according to the component design and is cast into a casting blank with the thickness of 300-450mm, the temperature of the preheating section is 960 ℃, the temperature of the heating section is 1225 ℃, the temperature of the heat preservation section is 1200 ℃, the heat preservation time of the heat preservation section is 50min, the integral heating time is 14min/cm, and the chemical components and the weight percentage of the steel blank are shown in table 1.
Secondly, three-stage rolling is carried out on the heated casting blank, the initial rolling temperature of the first stage is 1180 ℃, one-pass large reduction rolling is carried out, the reduction is 55mm, the thickness of the steel blank is changed from 300-450mm to 245-395 mm, and the final rolling temperature is 1100 ℃; the second stage is at the start rolling temperature of 931 ℃, then three rolling passes are carried out, the pass reduction is respectively 15mm, 15mm and 10mm, the thickness of the intermediate billet is 205 mm-355 mm, the intermediate billet is cooled to 850 ℃ after entering the IC, the third stage rolling is started, the rolling thickness is (according to the casting blank thickness of 300mm) 205mm-180mm-165mm-140mm-130mm-120mm in sequence, the cumulative reduction rate is 50.52% (if the casting blank thickness is more than 300mm, the cumulative reduction rate is larger), the final rolling temperature is 760 ℃, and the ACC cooling is rapidly carried out after the rolling is finished;
thirdly, opening the group number by adjusting the collecting pipes after entering the ACC, controlling the cooling speed at 10 ℃/S and the temperature of returning red at 520 ℃, and quickly straightening after going out of the ACC;
fourthly, straightening the steel plate, and then performing down-line stack cooling at the stack cooling temperature of 450 ℃ for 48 hours;
after the end of the cooling, the performance results of the steel plate sampling test are shown in table 2.
The novel high-strength extra-thick FH500 steel plate for ocean engineering with the thickness of 80-120mm is obtained through the processes of molten iron pretreatment, converter smelting, LF refining, VD vacuum degassing, continuous casting pouring, heating, rolling, heap cooling and the like. The chemical components and mechanical properties are shown in the following tables 1 and 2:
TABLE 1 FH500 Steel plate chemical composition
TABLE 2 FH500 steel sheet mechanical properties
The test for producing FH500 steel plates with the thickness of 80-120mm totally comprises 60 batches, all performance indexes reach standard requirements and have large margin, wherein the yield strength is 520-595 MPa, the tensile strength is 630-750 MPa, the elongation is 17% -25%, the V-type longitudinal impact energy is 168-306J at the temperature of 60 ℃ below zero, and the V-type transverse impact energy is 143-296J at the temperature of 60 ℃ below zero, and completely reaches the FH500 standard requirements.
External inspection and flaw detection: the external inspection of the steel plate obtained by the test is strictly checked according to the standard, the rate of qualified products is 100%, the flaw detection is carried out according to GB/T2970, wherein the proportion of the steel plate reaching the first-level standard is 90%, the proportion of the steel plate reaching the third-level standard is 100%, and the expected effect is achieved.
Claims (2)
1. A production method of a novel high-strength extra-thick FH500 steel plate for ocean engineering is characterized in that: the thickness of the steel plate is 300-450mm, and the steel plate comprises the following chemical components in percentage by mass: 0.080-0.11% of C, 0.20-0.50% of Si, 1.45-1.60% of Mn, less than or equal to 0.012% of P, less than or equal to 0.005% of S, 0.5-1.00% of Cr, 0.25-1.1% of Ni, 0.030-0.050% of Nb, 0.03-0.08% of V, 0.35-0.95% of Mo, 0.015-0.022% of Ti, 0.0010-0.0020% of B, less than or equal to 0.050% of Als, and the balance of Fe and residual elements;
the thickness of the steel plate is 80-120mm, the yield strength is 520-595 MPa, the tensile strength is 630-750 MPa, the elongation is 17% -25%, the longitudinal impact energy at the temperature of V-60 ℃ is 168-306J, and the transverse impact energy at the temperature of V-60 ℃ is 143-296J;
the production method of the steel plate comprises the following steps of molten iron pretreatment, converter smelting, LF refining, VD vacuum degassing, continuous casting and pouring, heating, rolling and heap cooling:
wherein in the heating process, the billet with the thickness of 300-;
in the rolling process, three-stage controlled rolling is carried out on a billet, the first stage is austenite recrystallization area rolling, a high-temperature, low-speed and large reduction process is adopted, the rolling temperature is controlled to be 1050-1200 ℃, the pass reduction is not less than 45mm, so that the rolling force reaches the core of the billet, on one hand, the recrystallization of the core of the casting blank is promoted, the foundation is laid for the grain refinement of the core, on the other hand, the deformation of the core of the billet is promoted, and the segregation and the defects of the core of the casting blank are greatly improved; the second stage is still rolling in an austenite recrystallization region, the rolling temperature is controlled to be 930-1000 ℃, the pass reduction is controlled according to 10-30mm, the rolling force reaches the thickness position of a casting blank 1/4, the deformation of the position 1/4 is promoted, and the aims of recrystallization at the position of a casting blank 1/4 and creating conditions for grain refinement are finally achieved, when the thickness of an intermediate blank reaches 1.5-2.0 times of the thickness of a finished product, the second stage rolling is finished, and the intermediate blank enters an IC device for rapid cooling; and when the temperature of the intermediate blank is 850-900 ℃, rolling in an austenite non-recrystallization region in the third stage is started, the accumulated reduction rate in the stages is more than or equal to 50%, and the final rolling temperature is 750-800 ℃, so that the effective area of austenite grain boundaries is increased, more nucleation points are provided for austenite transformation, and the effect of refining grains is achieved. After rolling, the steel plate enters ACC for cooling, the cooling speed is controlled to be 5-15 ℃/S, the temperature of red returning is controlled to be 500-600 ℃, crystal grains in the rolled steel plate can be prevented from growing up, impact toughness is affected, and the steel plate is guaranteed to have good strength and toughness;
in the heap cooling process, the steel plate is straightened, then the steel plate is off-line and is subjected to heap cooling, the heap cooling temperature is more than or equal to 350 ℃, and the heap cooling time is more than or equal to 24 hours, so that the steel plate with the thickness of 80-120mm is obtained. Through slow cooling, to avoid inside stress to too late release to produce the internal crack, further impel the inside harmful gas of steel sheet to spill over simultaneously.
2. The production method of the novel FH500 steel plate for high-strength extra-thick ocean engineering according to claim 1, characterized in that: the steel plate mainly comprises bainite, and contains a small amount of ferrite and pearlite, wherein the volume fraction of the bainite is 80-90%, the volume fraction of the ferrite is 5-10%, and the volume fraction of the pearlite is 5-10%.
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| CN115094217A (en) * | 2022-07-12 | 2022-09-23 | 南阳汉冶特钢有限公司 | 30CrMoA steel plate and production method thereof |
| CN115717219A (en) * | 2022-11-26 | 2023-02-28 | 南阳汉冶特钢有限公司 | High-strength steel Q610CF for hydroelectric engineering and production method thereof |
| CN115896618A (en) * | 2022-11-12 | 2023-04-04 | 南阳汉冶特钢有限公司 | Production method of novel high-strength HY690MD steel plate |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115094217A (en) * | 2022-07-12 | 2022-09-23 | 南阳汉冶特钢有限公司 | 30CrMoA steel plate and production method thereof |
| CN115896618A (en) * | 2022-11-12 | 2023-04-04 | 南阳汉冶特钢有限公司 | Production method of novel high-strength HY690MD steel plate |
| CN115717219A (en) * | 2022-11-26 | 2023-02-28 | 南阳汉冶特钢有限公司 | High-strength steel Q610CF for hydroelectric engineering and production method thereof |
| CN115717219B (en) * | 2022-11-26 | 2024-02-27 | 南阳汉冶特钢有限公司 | High-strength steel Q610CF for hydropower engineering and production method thereof |
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