CN111118257A - Heat treatment method for improving impact toughness of boron-containing thick hydroelectric steel plate core - Google Patents
Heat treatment method for improving impact toughness of boron-containing thick hydroelectric steel plate core Download PDFInfo
- Publication number
- CN111118257A CN111118257A CN202010048274.3A CN202010048274A CN111118257A CN 111118257 A CN111118257 A CN 111118257A CN 202010048274 A CN202010048274 A CN 202010048274A CN 111118257 A CN111118257 A CN 111118257A
- Authority
- CN
- China
- Prior art keywords
- steel plate
- temperature
- heat treatment
- rolling
- boron
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- 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
- C21D1/18—Hardening; Quenching with or without subsequent tempering
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
-
- 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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—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
-
- 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
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
-
- 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
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
-
- 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
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The invention discloses a heat treatment method for improving the impact toughness of a boron-containing thick hydroelectric steel plate core, which comprises the following heat treatment procedures of quenching, high-temperature tempering and rapid cooling after tempering; the quenching heating temperature is 920 ℃, the heat preservation time is 20 minutes, and the temperature of the quenched steel plate is less than or equal to 50 ℃. The tempering temperature of the steel plate is 660 ℃, the heat preservation time is 20 minutes, and the steel plate is quickly cooled to below 50 ℃ by water after being taken out of the furnace. The invention aims to provide a heat treatment method for improving the impact toughness of a boron-containing thick hydroelectric steel plate core, which greatly improves the impact toughness of the thick hydroelectric steel plate core and can obviously improve the stability of the impact performance of the thick hydroelectric steel plate core.
Description
Technical Field
The invention relates to the technical field of metallurgy, in particular to a heat treatment method for improving the impact toughness of a boron-containing thick hydroelectric steel plate core.
Background
The thick steel plate for hydropower is used for manufacturing a hydropower station water diversion pressure pipeline, a primary ribbed plate, a branch pipe, a volute and the like, has strict requirements on the performances of the steel plate such as chemical components, tensile strength, low-temperature impact energy and the like, generally requires that the tensile strength is higher than 610MPa, the strength distribution of the steel plate is concentrated, and the dispersion is small; the steel plate has lower welding crack sensitivity and reheating crack sensitivity and good welding performance. The national standard provides strict requirements for the core impact toughness of a steel plate with the thickness of more than 36mm, the core of the steel plate is the weakest place, trace boron is often added in component design in order to ensure that the thick-specification hydroelectric steel simultaneously has lower carbon equivalent, welding crack sensitivity and good welding performance, and the high strength and the low production cost of more than 610MP, and a large number of researches and practices show that the hardenability of the thick-specification steel plate can be obviously improved by the trace boron on the premise of not increasing the carbon equivalent and the production cost, so that the strength of the thick-specification steel plate is obviously improved. Meanwhile, negative effects are brought, and the crystal boundary precipitation of boron can obviously deteriorate the core impact toughness of the thick steel plate, so that the improvement of the core impact toughness of the thick steel plate becomes a technical difficulty and innovation point for researching and producing the steel for hydroelectric power.
Patent CN107760987A discloses a 15CrMoR steel plate and a method for improving the low-temperature impact toughness of the core thereof, and the heat treatment method of the normalizing and tempering process improves the low-temperature impact toughness of the core of the 15CrMoR steel plate with thick specification by preheating treatment before normalizing. The method has the defects that the method is only suitable for 15CrMoR steel plates, is not suitable for other steel plates and increases the production cost.
Patent CN101876001A discloses a method for improving low-temperature impact toughness of a high-strength thick steel plate, which adopts a heat treatment process of quenching + tempering to control the structure of the steel plate after secondary quenching to be a mixed structure of hard phase and soft phase, thereby improving the low-temperature toughness of the steel plate. The defects that two times of quenching are adopted, so that the production cost is obviously increased; secondly, the method can only improve the impact toughness of the thick steel plate 1/4, and the improvement effect on the central impact toughness is unknown.
Patent CN105420468A discloses a heat treatment method for ensuring low-temperature toughness of thick high-strength steel, which improves the low-temperature toughness of the thick high-strength steel through heat treatment methods of quenching, tempering and secondary tempering. The defects that the tempering furnace is only suitable for the steel grade, twice tempering is adopted, and the production cost is obviously increased; secondly, the method can only improve the impact toughness of the thick steel plate 1/4, and the improvement effect on the central impact toughness is unknown.
Disclosure of Invention
In order to solve the technical problems, the invention aims to provide a heat treatment method for improving the impact toughness of the center of a boron-containing thick hydroelectric steel plate, which greatly improves the impact toughness of the center of the thick hydroelectric steel plate and can obviously improve the stability of the impact property of the center of the thick hydroelectric steel plate.
In order to solve the technical problems, the invention adopts the following technical scheme:
a heat treatment method for improving the impact toughness of a boron-containing thick hydroelectric steel plate core comprises the heat treatment procedures of quenching, high-temperature tempering and rapid cooling after tempering; the quenching heating temperature is 920 ℃, the heat preservation time is 20 minutes, the temperature of the quenched steel plate is less than or equal to 50 ℃, the tempering temperature of the steel plate is 660 ℃, the heat preservation time is 20 minutes, and the steel plate is rapidly cooled to below 50 ℃ by water after being taken out of the furnace.
Further, the heat treatment process further comprises the following steps:
1) and smelting
Molten iron and high-quality scrap steel subjected to desulfurization pretreatment are used as raw materials, a converter bottom blowing mode is a full-process argon blowing mode, and the end point is hit once, so that nitrogen increase of the molten steel due to blowing supplement is reduced; further deoxidizing, desulfurizing, removing impurities, adjusting components and temperature of the LF ladle refining furnace, strictly controlling argon blowing strength, making an argon blowing curve according to the principles of early-stage strength, middle-stage strength and later-stage strength, and reducing secondary oxidation and nitrogen increase in the refining process while ensuring deoxidation, deep desulfurization and alloying; the RH process adopts a cyclic deep degassing process, firstly titanium iron is added, then ferroboron is added, the degassing time is more than 20 minutes, and the soft blowing time after calcium treatment is more than 10 minutes; on the premise of ensuring the temperature stability of the molten steel, the contents of gases such as hydrogen, oxygen, nitrogen and the like are greatly reduced, the adverse effect of harmful gases on the steel quality is reduced, and the purity of the molten steel is ensured;
2) and continuous casting
The continuous casting machine is a straight arc continuous casting machine, the defects of central segregation, central porosity, cracks, vibration marks and the like of the continuous casting billet are reduced by adopting a solidification tail end dynamic soft reduction, electromagnetic stirring and optimized dynamic secondary cooling technology through a constant temperature and constant drawing speed process, the superheat degree of molten steel is controlled to be 20-25 ℃, the drawing speed is controlled to be 0.85-0.90 m/min, and finally a high-quality continuous casting slab with the low-power mass of 3.0 levels of central segregation C and the central porosity of less than 3.0 levels is produced;
3) and heating the mixture
Heating the steel plate blank in a heating furnace, fully ensuring the heating temperature and soaking time of the steel plate blank, controlling the heating temperature to be 1200-1230 ℃, controlling the heating time to be 220-260 min, ensuring the full solid solution of alloy elements and the uniform temperature of the steel plate blank in the thickness direction, the length direction and the width direction;
4) rolling and cooling
The rolling adopts two-stage controlled rolling, namely austenite recrystallization region controlled rolling which is a rough rolling stage and austenite non-recrystallization region controlled rolling which is a finish rolling stage; during rough rolling, the single-pass deformation is increased as much as possible, the initial rolling temperature is more than or equal to 1100 ℃, the relative reduction rate of at least two passes is controlled to be more than 15%, the deformation of each pass is strictly controlled during finish rolling, the initial rolling temperature of the finish rolling is less than or equal to 890 ℃, the initial rolling thickness is 2.0-2.5 times of the thickness of a finished product, the final rolling temperature is 800-830 ℃, a rolled steel plate is subjected to controlled cooling, the final cooling temperature is 620-640 ℃, and the steel plate enters a cooling bed for air cooling after being thermally straightened;
5) finishing and inspection
The hot rolled steel sheet was subjected to flaw detection entirely after cooling, and the steel sheet was kept dry after flaw detection, and was subjected to off-line flaw detection according to the specification of flaw detection Standard JB/T4730.3, and judged as a pass grade I.
Further, the steel plate comprises the following chemical components in percentage by mass: c: 0.055-0.075%, Si 0.20-0.30%, Mn: 1.38-1.45% of P, less than or equal to 0.015% of S, less than or equal to 0.004%, 0.10-0.18% of Cr, 0.20-0.28% of Ni, 0.15-0.20% of Mo, Nb: 0.045-0.055%, V: 0.03 to 0.04%, Ti: 0.008 to 0.015 percent, 0.0007 to 0.0015 percent of B, less than or equal to 0.40 percent of Ceq, less than or equal to 0.20 percent of Pcm, and the balance of Fe and inevitable impurities.
Further, the steel plate comprises the following chemical components in percentage by mass: c: 0.059%, Si 0.25%, Mn: 1.41%, P: 0.009%, S: 0.001%, Cr 0.13%, Ni 0.24%, Mo 0.17%, Nb: 0.046%, V: 0.034%, Ti: 0.012%, 0.0011% B, 0.38% Ceq, 0.18% Pcm, and the balance Fe and inevitable impurities.
Further, the steel plate comprises the following chemical components in percentage by mass: c: 0.063%, Si 0.26%, Mn: 1.39%, P: 0.008%, S: 0.001%, Cr 0.13%, Ni 0.23%, Mo 0.17%, Nb: 0.047%, V: 0.032%, Ti: 0.012%, 0.0013% B, 0.38% Ceq, 0.18% Pcm, and the balance Fe and inevitable impurities.
Further, the steel plate comprises the following chemical components in percentage by mass: c: 0.072%, Si 0.24%, Mn: 1.41%, P: 0.010%, S: 0.001%, Cr 0.12%, Ni 0.23%, Mo 0.17%, Nb: 0.047%, V: 0.033%, Ti: 0.012%, 0.0011% B, 0.38% Ceq, 0.18% Pcm, and the balance Fe and inevitable impurities.
Further, quenching treatment is carried out after the steel plate is shot-blasted, the quenching heating temperature is 920 ℃, the heat preservation time is 20 minutes, the steel plate tempering temperature is 660 ℃, the heat preservation time is 20 minutes, and the steel plate is rapidly cooled to 32 ℃ after being discharged from the furnace.
Compared with the prior art, the invention has the beneficial technical effects that:
according to the invention, by adopting the heat treatment method of rapid cooling after quenching and high-temperature tempering, the crystal boundary precipitation of boron is inhibited, the low-temperature impact toughness of the center part of the boron-containing thick hydroelectric steel plate is greatly improved, and conditions are created for stably producing the thick hydroelectric steel plate by adopting a continuous casting plate blank with the thickness of 250 mm.
Through actual production and inspection, the mechanical property of the steel plate is excellent, the central impact property of the steel plate at the temperature of minus 20 ℃ is stably controlled to be more than 80J, and the technical difficulty of the production of thick hydroelectric steel is solved.
Drawings
The invention is further illustrated in the following description with reference to the drawings.
FIG. 1 shows the metallographic structure of the core of a steel sheet according to example 1 of the present invention.
FIG. 2 shows the metallographic structure of the core of the steel sheet of comparative example 1 of the present invention.
Detailed Description
Example 1
The raw material molten iron is subjected to molten iron deep desulfurization, converter top and bottom blowing, ladle argon blowing, LF external refining, RH vacuum treatment and continuous casting processes to obtain a 250mm thick plate blank with the chemical components in percentage by weight shown in Table 1. The heating temperature of the plate blank is 1226 ℃, the heating time is 260min, the starting rolling temperature of the first stage is 1180 ℃, the relative reduction rate of at least two passes of the first stage is controlled to be more than 15%, when the thickness of a rolled piece is 109mm, the temperature is kept to 883 ℃ on a roller way, then the second stage rolling is carried out, the final rolling temperature is 818 ℃, and the thickness of a finished steel plate is 46 mm. After the rolling is finished, the steel plate enters an accelerated cooling (ACC) device, is cooled to 642 ℃ at the speed of 8 ℃/s, and is cooled by a cooling bed after hot straightening. And then carrying out online flaw detection and finishing treatment, carrying out quenching treatment after the steel plate is shot-blasted, wherein the quenching heating temperature is 920 ℃, the heat preservation time is 20 minutes, the steel plate tempering temperature is 660 ℃, the heat preservation time is 20 minutes, and the steel plate is quickly cooled to 32 ℃ after being discharged from a furnace, so that the steel plate can be obtained. Referring to fig. 1 and 2, the metallographic structure of the core of the steel sheet according to example 1 and comparative example 1 (conventional heat treatment method) of the present invention is shown.
Example 2
The implementation mode is the same as that of the embodiment 1, wherein the heating temperature is 1225 ℃, the heating time is 262min, the initial rolling temperature of the first stage rolling is 1160 ℃, the initial rolling temperature of the second stage rolling is 886 ℃, the thickness of a rolled piece is 131mm, the final rolling temperature is 824 ℃, and the thickness of a finished steel plate is 52 mm. The cooling speed of the steel plate is 8 ℃/s, and the final cooling temperature is 653 ℃. And cooling the cooling bed after the thermal correction. And then carrying out flaw detection and finishing treatment, carrying out quenching treatment after the steel plate is shot-blasted, wherein the quenching heating temperature is 920 ℃, the heat preservation time is 20 minutes, the steel plate tempering temperature is 660 ℃, the heat preservation time is 20 minutes, and the steel plate is quickly cooled to 20 ℃ after being taken out of the furnace, so that the steel plate can be obtained.
Example 3
The implementation mode is the same as that of example 1, wherein the heating temperature is 1224 ℃, the heating time is 263min, the initial rolling temperature of the first-stage rolling is 1175 ℃, the initial rolling temperature of the second-stage rolling is 886 ℃, the thickness of a rolled piece is 130mm, the final rolling temperature is 830 ℃, and the thickness of a finished steel plate is 64 mm. The cooling speed of the steel plate is 8 ℃/s, and the final cooling temperature is 642 ℃. And cooling the cooling bed after the thermal correction. And then carrying out flaw detection and finishing treatment, carrying out quenching treatment after the steel plate is shot-blasted, wherein the quenching heating temperature is 920 ℃, the heat preservation time is 20 minutes, the steel plate tempering temperature is 660 ℃, the heat preservation time is 20 minutes, and the steel plate is quickly cooled to 26 ℃ after being discharged from the furnace, thus obtaining the steel plate.
TABLE 1 chemical composition (wt%) of inventive examples 1 to 3
| Practice of | C | Si | Mn | P | S | Nb | V | Ti | Ni | Cr | Mo | B | Ceq | Pcm |
| 1 | 0.059 | 0.25 | 1.41 | 0.009 | 0.001 | 0.046 | 0.034 | 0.012 | 0.24 | 0.13 | 0.17 | 0.0011 | 0.38 | 0.18 |
| 2 | 0.063 | 0.26 | 1.39 | 0.008 | 0.001 | 0.047 | 0.032 | 0.012 | 0.23 | 0.13 | 0.17 | 0.0013 | 0.38 | 0.18 |
| 3 | 0.072 | 0.24 | 1.41 | 0.010 | 0.001 | 0.047 | 0.033 | 0.012 | 0.23 | 0.12 | 0.17 | 0.0011 | 0.39 | 0.18 |
The steel plates of the invention examples 1-3 were tested for conventional mechanical properties, impact properties, and bending properties, and the results are shown in table 2.
TABLE 2 mechanical Properties of Steel sheets according to examples 1 to 3 of the present invention
As can be seen from Table 2, the comparative example is the steel sheet property after the conventional heat treatment method, the impact property of the steel sheet core is deteriorated due to the precipitation of boron grain boundary, and the standard requirement is not met. Examples 1-3 show that the performance of the steel plate after the invention is adopted, the 'rapid cooling after tempering' process effectively inhibits the precipitation of boron crystal boundary, the core impact performance and the stability are obviously improved, and the technical difficulty of the production of thick hydroelectric steel is solved.
The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.
Claims (7)
1. A heat treatment method for improving the impact toughness of a boron-containing thick hydroelectric steel plate core is characterized in that the heat treatment process comprises quenching, high-temperature tempering and rapid cooling after tempering; the quenching heating temperature is 920 ℃, the heat preservation time is 20 minutes, the temperature of the quenched steel plate is less than or equal to 50 ℃, the tempering temperature of the steel plate is 660 ℃, the heat preservation time is 20 minutes, and the steel plate is rapidly cooled to below 50 ℃ by water after being taken out of the furnace.
2. The heat treatment method for improving the impact toughness of the center of the boron-containing thick-gauge hydroelectric steel plate according to claim 1, wherein the heat treatment step further comprises:
1) and smelting
Molten iron and high-quality scrap steel subjected to desulfurization pretreatment are used as raw materials, a converter bottom blowing mode is a full-process argon blowing mode, and the end point is hit once, so that nitrogen increase of the molten steel due to blowing supplement is reduced; further deoxidizing, desulfurizing, removing impurities, adjusting components and temperature of the LF ladle refining furnace, strictly controlling argon blowing strength, making an argon blowing curve according to the principles of early-stage strength, middle-stage strength and later-stage strength, and reducing secondary oxidation and nitrogen increase in the refining process while ensuring deoxidation, deep desulfurization and alloying; the RH process adopts a cyclic deep degassing process, firstly titanium iron is added, then ferroboron is added, the degassing time is more than 20 minutes, and the soft blowing time after calcium treatment is more than 10 minutes; on the premise of ensuring the temperature stability of the molten steel, the contents of gases such as hydrogen, oxygen, nitrogen and the like are greatly reduced, the adverse effect of harmful gases on the steel quality is reduced, and the purity of the molten steel is ensured;
2) and continuous casting
The continuous casting machine is a straight arc continuous casting machine, the defects of central segregation, central porosity, cracks, vibration marks and the like of the continuous casting billet are reduced by adopting a solidification tail end dynamic soft reduction, electromagnetic stirring and optimized dynamic secondary cooling technology through a constant temperature and constant drawing speed process, the superheat degree of molten steel is controlled to be 20-25 ℃, the drawing speed is controlled to be 0.85-0.90 m/min, and finally a high-quality continuous casting slab with the low-power mass of 3.0 levels of central segregation C and the central porosity of less than 3.0 levels is produced;
3) and heating the mixture
Heating the steel plate blank in a heating furnace, fully ensuring the heating temperature and soaking time of the steel plate blank, controlling the heating temperature to be 1200-1230 ℃, controlling the heating time to be 220-260 min, ensuring the full solid solution of alloy elements and the uniform temperature of the steel plate blank in the thickness direction, the length direction and the width direction;
4) rolling and cooling
The rolling adopts two-stage controlled rolling, namely austenite recrystallization region controlled rolling which is a rough rolling stage and austenite non-recrystallization region controlled rolling which is a finish rolling stage; during rough rolling, the single-pass deformation is increased as much as possible, the initial rolling temperature is more than or equal to 1100 ℃, the relative reduction rate of at least two passes is controlled to be more than 15%, the deformation of each pass is strictly controlled during finish rolling, the initial rolling temperature of the finish rolling is less than or equal to 890 ℃, the initial rolling thickness is 2.0-2.5 times of the thickness of a finished product, the final rolling temperature is 800-830 ℃, a rolled steel plate is subjected to controlled cooling, the final cooling temperature is 620-640 ℃, and the steel plate enters a cooling bed for air cooling after being thermally straightened;
5) finishing and inspection
The hot rolled steel sheet was subjected to flaw detection entirely after cooling, and the steel sheet was kept dry after flaw detection, and was subjected to off-line flaw detection according to the specification of flaw detection Standard JB/T4730.3, and judged as a pass grade I.
3. The heat treatment method for improving the impact toughness of the center of the boron-containing thick-gauge hydroelectric steel plate according to claim 1 or 2, wherein the steel plate comprises the following chemical components in percentage by mass: c: 0.055-0.075%, Si 0.20-0.30%, Mn: 1.38-1.45% of P, less than or equal to 0.015% of S, less than or equal to 0.004%, 0.10-0.18% of Cr, 0.20-0.28% of Ni, 0.15-0.20% of Mo, Nb: 0.045-0.055%, V: 0.03 to 0.04%, Ti: 0.008 to 0.015 percent, 0.0007 to 0.0015 percent of B, less than or equal to 0.40 percent of Ceq, less than or equal to 0.20 percent of Pcm, and the balance of Fe and inevitable impurities.
4. The heat treatment method for improving the impact toughness of the center of the boron-containing thick-gauge hydroelectric steel plate according to claim 3, wherein the steel plate comprises the following chemical components in percentage by mass: c: 0.059%, Si 0.25%, Mn: 1.41%, P: 0.009%, S: 0.001%, Cr 0.13%, Ni 0.24%, Mo 0.17%, Nb: 0.046%, V: 0.034%, Ti: 0.012%, 0.0011% B, 0.38% Ceq, 0.18% Pcm, and the balance Fe and inevitable impurities.
5. The heat treatment method for improving the impact toughness of the center of the boron-containing thick-gauge hydroelectric steel plate according to claim 3, wherein the steel plate comprises the following chemical components in percentage by mass: c: 0.063%, Si 0.26%, Mn: 1.39%, P: 0.008%, S: 0.001%, Cr 0.13%, Ni 0.23%, Mo 0.17%, Nb: 0.047%, V: 0.032%, Ti: 0.012%, 0.0013% B, 0.38% Ceq, 0.18% Pcm, and the balance Fe and inevitable impurities.
6. The heat treatment method for improving the impact toughness of the center of the boron-containing thick-gauge hydroelectric steel plate according to claim 3, wherein the steel plate comprises the following chemical components in percentage by mass: c: 0.072%, Si 0.24%, Mn: 1.41%, P: 0.010%, S: 0.001%, Cr 0.12%, Ni 0.23%, Mo 0.17%, Nb: 0.047%, V: 0.033%, Ti: 0.012%, 0.0011% B, 0.38% Ceq, 0.18% Pcm, and the balance Fe and inevitable impurities.
7. The heat treatment method for improving the impact toughness of the center of the boron-containing thick-gauge hydroelectric steel plate as claimed in claim 1, wherein the steel plate is quenched after being shot-blasted, the quenching heating temperature is 920 ℃, the holding time is 20 minutes, the steel plate tempering temperature is 660 ℃, the holding time is 20 minutes, and the steel plate is rapidly cooled to 32 ℃ after being discharged from a furnace.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010048274.3A CN111118257A (en) | 2020-01-16 | 2020-01-16 | Heat treatment method for improving impact toughness of boron-containing thick hydroelectric steel plate core |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010048274.3A CN111118257A (en) | 2020-01-16 | 2020-01-16 | Heat treatment method for improving impact toughness of boron-containing thick hydroelectric steel plate core |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111118257A true CN111118257A (en) | 2020-05-08 |
Family
ID=70490770
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010048274.3A Pending CN111118257A (en) | 2020-01-16 | 2020-01-16 | Heat treatment method for improving impact toughness of boron-containing thick hydroelectric steel plate core |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111118257A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114134407A (en) * | 2021-06-04 | 2022-03-04 | 江阴兴澄特种钢铁有限公司 | Easy-to-weld steel plate with excellent low-temperature toughness at core for volute and manufacturing method thereof |
| CN114622073A (en) * | 2022-03-09 | 2022-06-14 | 包头钢铁（集团）有限责任公司 | Method for improving low-temperature impact toughness of boron-containing steel by using sub-temperature quenching |
| CN115011887A (en) * | 2022-06-21 | 2022-09-06 | 湖南华菱湘潭钢铁有限公司 | Production method of low-yield-ratio Q500F quenched and tempered steel plate |
| CN115852120A (en) * | 2022-11-29 | 2023-03-28 | 南京钢铁股份有限公司 | Production method of P690QL2 steel plate with thickness less than or equal to 50mm |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102242309A (en) * | 2011-06-30 | 2011-11-16 | 湖南华菱湘潭钢铁有限公司 | Production method of boron-containing petroleum storage tank steel plate for ultra-high heat input welding |
| CN102382966A (en) * | 2011-10-14 | 2012-03-21 | 南京钢铁股份有限公司 | Accelerating cooling technology after medium plate tempering |
| CN103045965A (en) * | 2012-12-27 | 2013-04-17 | 内蒙古包钢钢联股份有限公司 | Technique for manufacturing steel plate for 600MPa hydropower steel penstock |
| CN105603310A (en) * | 2016-01-18 | 2016-05-25 | 内蒙古包钢钢联股份有限公司 | Low-yield-ratio Q420GJ steel plate for buildings and production method of low-yield-ratio Q420GJ steel plate for buildings |
| CN107119229A (en) * | 2017-06-23 | 2017-09-01 | 江苏省沙钢钢铁研究院有限公司 | A kind of method for reducing quenching and tempering type high-strength steel steel plate ductile-brittle transition temperature |
-
2020
- 2020-01-16 CN CN202010048274.3A patent/CN111118257A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102242309A (en) * | 2011-06-30 | 2011-11-16 | 湖南华菱湘潭钢铁有限公司 | Production method of boron-containing petroleum storage tank steel plate for ultra-high heat input welding |
| CN102382966A (en) * | 2011-10-14 | 2012-03-21 | 南京钢铁股份有限公司 | Accelerating cooling technology after medium plate tempering |
| CN103045965A (en) * | 2012-12-27 | 2013-04-17 | 内蒙古包钢钢联股份有限公司 | Technique for manufacturing steel plate for 600MPa hydropower steel penstock |
| CN105603310A (en) * | 2016-01-18 | 2016-05-25 | 内蒙古包钢钢联股份有限公司 | Low-yield-ratio Q420GJ steel plate for buildings and production method of low-yield-ratio Q420GJ steel plate for buildings |
| CN107119229A (en) * | 2017-06-23 | 2017-09-01 | 江苏省沙钢钢铁研究院有限公司 | A kind of method for reducing quenching and tempering type high-strength steel steel plate ductile-brittle transition temperature |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114134407A (en) * | 2021-06-04 | 2022-03-04 | 江阴兴澄特种钢铁有限公司 | Easy-to-weld steel plate with excellent low-temperature toughness at core for volute and manufacturing method thereof |
| CN114622073A (en) * | 2022-03-09 | 2022-06-14 | 包头钢铁（集团）有限责任公司 | Method for improving low-temperature impact toughness of boron-containing steel by using sub-temperature quenching |
| CN114622073B (en) * | 2022-03-09 | 2024-02-23 | 包头钢铁（集团）有限责任公司 | Method for improving low-temperature impact toughness of boron-containing steel by utilizing sub-temperature quenching |
| CN115011887A (en) * | 2022-06-21 | 2022-09-06 | 湖南华菱湘潭钢铁有限公司 | Production method of low-yield-ratio Q500F quenched and tempered steel plate |
| CN115852120A (en) * | 2022-11-29 | 2023-03-28 | 南京钢铁股份有限公司 | Production method of P690QL2 steel plate with thickness less than or equal to 50mm |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113278878B (en) | Hydrogen-induced cracking resistant pressure vessel steel plate with thickness of more than 200-250 mm and manufacturing method thereof | |
| CN111118257A (en) | Heat treatment method for improving impact toughness of boron-containing thick hydroelectric steel plate core | |
| CN113637917B (en) | 690 MPa-grade ultrahigh-strength extra-thick ship plate steel with excellent low-temperature impact performance and production method thereof | |
| CN109797339A (en) | A kind of tensile strength >=960MP martensite Micro Alloying high-strength steel and its manufacturing method | |
| CN109628828B (en) | Low-yield-ratio ultra-thick hydroelectric high-strength steel plate and manufacturing method thereof | |
| CN103361561B (en) | The preparation method of coupling material weldless steel tube | |
| CN111636034B (en) | Production method of corrosion-resistant rare earth high-performance bridge steel Q500qE wide and thick steel plate | |
| CN112813345A (en) | Non-quenched and tempered steel for cold machining engineering machinery hydraulic piston rod and preparation method | |
| CN105603310B (en) | A kind of low yield strength ratio Q420GJ steel plate for building and its production method | |
| CN113846260A (en) | Production method of high-strength steel plate for engineering machinery | |
| CN112877586A (en) | Production method of high-strength and high-toughness American-standard steel rail for CR175 crane | |
| CN112210719A (en) | Low-cost high-performance Q500 bridge steel and production method thereof | |
| CN110592480A (en) | Thick Q345R steel plate with excellent low-temperature impact toughness at core and manufacturing method thereof | |
| CN111826580B (en) | High-strength easy-to-weld steel plate for ultra-thick large hydropower station and production method thereof | |
| CN115141969A (en) | Production method of 800MPa grade hydropower steel | |
| CN114606436A (en) | 370 MPa-grade rare earth weather-resistant structural steel for polar region and production method thereof | |
| CN111996462A (en) | Longitudinal variable-thickness ultrahigh-strength ship board and production method thereof | |
| CN111763880A (en) | Low-yield-ratio ultra-thick hydroelectric high-strength steel plate and manufacturing method thereof | |
| CN113444969B (en) | Steel plate for low-temperature service condition of American standard container and production method thereof | |
| CN115125448A (en) | Non-quenched and tempered steel for cold machining of hydraulic piston rod and preparation method | |
| CN114875310A (en) | Normalizing type thick-specification Q370R pressure vessel steel plate | |
| CN111235479B (en) | Manufacturing method of economical pipeline steel | |
| CN110724875B (en) | Steel plate for railway and manufacturing method for improving yield strength of steel plate | |
| CN114086051B (en) | High-strength high-toughness easily-welded nano steel with thickness of 60-120 mm and thickness of 850MPa and preparation method thereof | |
| CN116043135B (en) | Ultra-high toughness P690QL2 steel plate and manufacturing method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |