WO2024109390A1 - 一种高强度水电工程用hy950cf钢板及其生产方法 - Google Patents

一种高强度水电工程用hy950cf钢板及其生产方法 Download PDF

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WO2024109390A1
WO2024109390A1 PCT/CN2023/124770 CN2023124770W WO2024109390A1 WO 2024109390 A1 WO2024109390 A1 WO 2024109390A1 CN 2023124770 W CN2023124770 W CN 2023124770W WO 2024109390 A1 WO2024109390 A1 WO 2024109390A1
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temperature
rolling
steel plate
heating
quenching
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PCT/CN2023/124770
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English (en)
French (fr)
Inventor
朱书成
袁继恒
李忠波
许少普
张涛
康文举
陈熙
王英杰
李博
李亮
陈良
符可义
度鹏
周富磊
朱先兴
袁高俭
任义
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南阳汉冶特钢有限公司
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Publication of WO2024109390A1 publication Critical patent/WO2024109390A1/zh

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/58—Roll-force control; Roll-gap control
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • 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
    • 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
    • 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
    • C22C33/06—Making ferrous alloys by melting using master alloys
    • 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
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • 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
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • 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

Definitions

  • the present invention belongs to the field of medium and thick plate production, and specifically relates to a high-strength HY950CF steel plate for hydropower engineering and a production method thereof.
  • the hydropower stations with a capacity of more than 5 million kW include Xiangjiaba, Xiluodu, Baihetan, Wudongde, Longpanxia, etc.
  • the highest head of the pressure steel pipe has reached 1200m
  • the wall thickness of the high-strength steel pipe has reached 90mm
  • the thickness of the high-strength steel crescent rib has reached 150mm
  • the HD value H refers to the internal pressure head borne by the volute
  • D refers to the diameter of the volute inlet section
  • the present disclosure provides a high-strength HY950CF steel plate for hydropower engineering, wherein the thickness of the steel plate is 50 to 120 mm and the steel plate comprises the following chemical components in mass percentage:
  • the present disclosure also provides a high-strength HY950CF steel plate for hydropower engineering, wherein the thickness of the steel plate is 50 to 120 mm and comprises the following chemical components in mass percentage:
  • the present disclosure also provides a method for producing a steel plate, the method comprising the following steps:
  • Step 1 Casting molten steel to obtain a steel ingot, wherein a heating wire is added during the casting;
  • Step 2 The steel ingot obtained in step 1 is heated once, wherein the target holding temperature in the high temperature section is 1220-1240° C. and the holding time is 16-18 hours;
  • Step 3 The steel ingot heated in step 2 is subjected to blank rolling to obtain a steel plate, wherein the starting rolling temperature is 1050-1100° C., the pass reduction is 60-70 mm, and the temperature of the steel plate at the end of rolling is controlled at 950-980° C.;
  • Step 4 The steel plate obtained in step 3 is subjected to secondary heating, wherein the target insulation temperature in the high temperature section is 1220-1240° C. and the insulation time is 5-6 hours;
  • Step 5 The steel plate heated in step 4 is subjected to secondary rolling, wherein the pass reduction is ⁇ 30 ⁇ 5mm, the start rolling temperature is ⁇ 1020°C, and the final rolling temperature is ⁇ 950°C. After rolling, the surface and core temperatures of the steel plate are lowered to the non-recrystallized zone;
  • Step 6 heat-treating the steel plate obtained in step 5, wherein the steel plate is sequentially subjected to high temperature quenching treatment, critical quenching treatment and tempering treatment; and the high temperature quenching heating temperature is 920-940°C, the critical quenching heating temperature is 860-870°C, and the tempering treatment temperature is 650 ⁇ 20°C;
  • Step 7 Cool the steel plate in step 6 to room temperature.
  • the body thickness of the steel ingot is 960-990 mm
  • the pouring temperature is controlled at 1555-1560° C.
  • Re wire is fed into the center pouring pipe during the pouring process at a wire feeding speed of 10-20 m/min.
  • step 1 the molten steel is obtained through molten iron pretreatment, converter smelting, argon blowing treatment, VD decarburization, LF refining and VD refining.
  • step 2 when the steel is charged for heating, the furnace temperature is ⁇ 750°C, and the steel is stewed for 2 to 4 hours before heating.
  • the total heating time is 10-20 min/cm.
  • the secondary rolling further includes a slab cutting operation.
  • the intermediate slab is placed in a soaking pit after being cut four times.
  • step 5 the secondary product rolling does not need to be widened again, and can be directly extended to the finished product thickness.
  • step 5 before the secondary rolling, high-pressure water is used for cooling, and rolling is started after the surface of the steel plate has fully returned to red.
  • the total secondary rolling time is 3 to 4 minutes.
  • step 5 after the secondary rolling is completed, ACC is turned on for water cooling twice to reduce the surface and core temperatures of the steel plate to the non-recrystallization zone; optionally, the water entry temperature of the steel plate is 900-950°C, and the red-return temperature of the steel plate is 800-830°C.
  • step 6 the heating temperature of the high temperature quenching is 920-940°C, the heating time is 2-3 min/mm, and the quenching water temperature is 15-18°C.
  • the critical quenching heating temperature is 860-870°C, the heating time is 2-3 min/mm, and the quenching water temperature is 15-18°C;
  • the tempering treatment is tempering in a quenching furnace at 650 ⁇ 20° C. and air cooling to room temperature.
  • the present disclosure also provides a method for producing the high-strength HY950CF steel plate for hydropower engineering.
  • the method comprises the following steps: ingot casting, primary heating, blank rolling, secondary heating and rolling, heat treatment, and includes,
  • the thickness of the ingot body is 960-990mm
  • the pouring temperature is controlled at 1555-1560°C
  • the hot wire is fed into the center pouring pipe during the pouring process, and the wire feeding speed is 10-20m/min;
  • the starting rolling temperature is 1050-1100°C
  • the pass reduction is 60-70mm
  • the billet is 400mm thick
  • the temperature of the steel plate is controlled at 950-980°C after rolling
  • Secondary heating and rolling process the intermediate billet is cut four times and then placed in a soaking pit.
  • the target temperature of the high temperature section is 1220-1240°C, and the total holding time is 5-6 hours. No need to widen again during the secondary rolling, and it can be directly extended to the finished product thickness.
  • the pass reduction is ⁇ 30 ⁇ 5mm
  • the start rolling temperature is ⁇ 1020°C
  • the final rolling temperature is ⁇ 950°C.
  • High-pressure water is used for cooling during the rolling process. Rolling can only be started after the surface of the steel plate has fully returned to red.
  • the total rolling time is controlled within 3-4 minutes.
  • ACC is turned on for two times of water cooling to quickly reduce the surface and core temperature of the steel plate to the non-recrystallization zone.
  • the water entry temperature is 900-950°C
  • the return to red temperature is 800-830°C.
  • Heat treatment process adopt high temperature quenching + critical quenching + tempering heat treatment, among which the high temperature quenching heating temperature is 920 ⁇ 940°C, the heating time is 2.4min/mm, and the quenching machine is cooled to room temperature after the hot steel plate is taken out of the furnace, and the water temperature is 15 ⁇ 18°C; the critical quenching heating temperature is 860 ⁇ 870°C, the heating time is 2.4min/mm, and the quenching machine is cooled to room temperature after the hot steel plate is taken out of the furnace, and the water temperature is 15 ⁇ 18°C; after quenching, it is loaded into the quenching furnace for tempering at 650 ⁇ 20°C, and air-cooled to room temperature.
  • the high temperature quenching heating temperature is 920 ⁇ 940°C
  • the heating time is 2.4min/mm
  • the quenching machine is cooled to room temperature after the hot steel plate is taken out of the furnace, and the water temperature is 15 ⁇ 18°C
  • the critical quenching heating temperature is 860
  • the present disclosure also provides a method for producing the steel plate, the method comprising the following steps:
  • Ingot casting, primary heating, billet rolling, secondary heating and rolling, heat treatment including:
  • the thickness of the ingot body is 960-990mm
  • the pouring temperature is controlled at 1555-1560°C
  • the heating wire is fed into the center pouring pipe during the pouring process to improve the internal quality
  • the wire feeding speed is 15m/min
  • the billet rolling process adopts "high temperature, low speed, and high pressure reduction", the rolling temperature is 1050 ⁇ 1100°C, and the pass pressure is The thickness of the steel plate is 60-70 mm, and the thickness of the steel plate is 400 mm. The temperature of the steel plate is controlled at 950-980°C after rolling.
  • Secondary heating and rolling process the intermediate billet is cut four times and then placed in a soaking pit.
  • the target temperature of the high temperature section is 1220-1240°C, and the total holding time is 5-6 hours. No need to widen again during the secondary rolling, and it can be directly extended to the finished product thickness.
  • the pass reduction is ⁇ 30 ⁇ 5mm
  • the start rolling temperature is ⁇ 1020°C
  • the final rolling temperature is ⁇ 950°C.
  • High-pressure water is used for cooling during the rolling process. Rolling can only be started after the surface of the steel plate has fully returned to red.
  • the total rolling time is controlled within 3-4 minutes.
  • ACC is turned on for two times of water cooling to quickly reduce the surface and core temperature of the steel plate to the non-recrystallization zone.
  • the water entry temperature is 900-950°C
  • the return to red temperature is 800-830°C.
  • Heat treatment process adopt high temperature quenching + critical quenching + tempering heat treatment, wherein the first quenching heating temperature is 920 ⁇ 940°C, the heating time is 2.4min/mm, and the quenching machine is cooled to room temperature after the hot steel plate is out of the furnace, and the water temperature is 15 ⁇ 18°C; the second quenching heating temperature is 860 ⁇ 870°C, the heating time is 2.4min/mm, and the quenching machine is cooled to room temperature after the hot steel plate is out of the furnace, and the water temperature is 15 ⁇ 18°C; after quenching, it is loaded into the quenching furnace for tempering at 650 ⁇ 20°C and air-cooled to room temperature.
  • the present disclosure also provides a steel plate prepared according to the aforementioned method.
  • the steel plate is a high-strength HY950CF steel plate for hydropower engineering, the thickness of the steel plate is 50 to 120 mm, and contains the following chemical components in mass percentage (unit, wt%):
  • the steel plate has a carbon equivalent Ceq ⁇ 0.7, a bainite tempered structure, and a -60°C longitudinal and transverse V-type impact energy ⁇ 127J.
  • FIG1 is a schematic diagram of the metallographic structure of a cross section of a 120 mm thick steel plate in an embodiment of the present disclosure (metallographic microscope, ⁇ 100).
  • FIG2 is a schematic diagram of the metallographic structure of a cross section of a 120 mm thick steel plate in an embodiment of the present disclosure (metallographic microscope, ⁇ 200).
  • FIG3 is a schematic diagram of the metallographic structure of a cross section of a 120 mm thick steel plate in an embodiment of the present disclosure (metallographic microscope, ⁇ 500).
  • Als used herein means acid-soluble aluminum.
  • Chinese patent CN 114395731 A discloses a low welding crack sensitivity arrest steel HY950CF for hydropower engineering.
  • the thickness of the steel plate is 20 to 100 mm, and the structure is a tempered troostite structure with martensite orientation.
  • the steel plate has the following chemical composition in mass percentage (unit, wt%): C 0.06-0.15, Si ⁇ 0.20, Mn 0.7-1.5, P ⁇ 0.008, S ⁇ 0.001, Als 0.015-0.060, V ⁇ 0.05, Cr 0.5-0.8, Ni 1.5-4.0, Mo 0.4-0.8, Nb ⁇ 0.04, B0.0008-0.0015, and the others are Fe and residual elements; the steel plate is delivered in the state of quenching and tempering, i.e., online quenching + tempering treatment.
  • the advantages of the disclosure are that the steel plate strength and toughness are matched by a reasonable composition ratio, the plate is thin, and the material is made by continuous casting, but with the construction of large-scale hydropower station projects with high water head, the current thickness and strength level of the steel plate can no longer meet the use requirements.
  • Chinese patent CN 105925887A discloses a 980MPa grade hot-rolled ferrite-bainite dual-phase steel, whose chemical composition weight percentage is: C: 0.15-0.30%, Si 0.8-2.0%, Mn: 1.0-2.0%, P ⁇ 0.02%, S ⁇ 0.005%, O ⁇ 0.003%, Al 0.5-1.0%, N ⁇ 0.006%, Nb: 0.01-0.06%, Ti: 0.01-0.05%, the rest is Fe and unavoidable impurities, and the above elements must also satisfy the following relationship: 0.05% ⁇ Nb + Ti ⁇ 0.10%, 2.5 ⁇ Al / C ⁇ 5.0.
  • the disclosed feature is the use of high carbon and high manganese composition design, the steel plate thickness is 3-6mm, the disadvantage is that the carbon equivalent is high and the weldability is poor.
  • the present invention discloses a high-strength HY950CF steel plate for hydropower engineering and a production method thereof.
  • the present disclosure provides a high-strength HY950CF steel plate for hydropower engineering, wherein the thickness of the steel plate is 50 to 120 mm and the steel plate comprises the following chemical components in mass percentage:
  • the present disclosure also provides a high-strength HY950CF steel plate for hydropower engineering, wherein the thickness of the steel plate is 50 to 120 mm and comprises the following chemical components in mass percentage:
  • the HY950CF steel plate disclosed in the present invention is micro-alloyed with multiple elements such as Nb, V, Cu, Cr, Ni, and Mo, thereby ensuring that HY950CF meets multiple special requirements such as high strength, high low-temperature impact toughness, weldability, and corrosion resistance. It is believed that, without any theoretical constraints, increasing the nickel content can not only strongly improve the strength of the extra-thick plate steel plate, but also promote its toughness to remain at a high level; chromium carbide is the smallest of various carbides, and it can be evenly distributed in the steel body.
  • Increasing the Cr content has an outstanding contribution to improving strength, hardness, and wear resistance; low-carbon design is conducive to improving low-temperature impact toughness; micro-alloying elements such as Nb, V, and Ti are crucial to toughness, strength, and weldability, and promote the formation of Various M (C, N) nano-precipitated phases; adding trace rare earth elements has the effect of purifying molten steel and modifying inclusions, which can improve the low-temperature impact toughness of rare earth steel.
  • the present disclosure also provides a method for producing a steel plate, the method comprising the following steps:
  • Step 1 Casting molten steel to obtain a steel ingot, wherein a heating wire is added during the casting;
  • Step 2 The steel ingot obtained in step 1 is heated once, wherein the target holding temperature in the high temperature section is 1220-1240° C. and the holding time is 16-18 hours;
  • Step 3 The steel ingot heated in step 2 is subjected to blank rolling to obtain a steel plate, wherein the starting rolling temperature is 1050-1100° C., the pass reduction is 60-70 mm, and the temperature of the steel plate at the end of rolling is controlled at 950-980° C.;
  • Step 4 The steel plate obtained in step 3 is subjected to secondary heating, wherein the target insulation temperature in the high temperature section is 1220-1240° C. and the insulation time is 5-6 hours;
  • Step 5 The steel plate heated in step 4 is subjected to secondary rolling, wherein the pass reduction is ⁇ 30 ⁇ 5mm, the start rolling temperature is ⁇ 1020°C, and the final rolling temperature is ⁇ 950°C. After rolling, the surface and core temperatures of the steel plate are lowered to the non-recrystallized zone;
  • Step 6 heat-treating the steel plate obtained in step 5, wherein the steel plate is sequentially subjected to high temperature quenching treatment, critical quenching treatment and tempering treatment; and the high temperature quenching heating temperature is 920-940°C, the critical quenching heating temperature is 860-870°C, and the tempering treatment temperature is 650 ⁇ 20°C;
  • Step 7 Cool the steel plate in step 6 to room temperature.
  • the steel plate obtained by the method disclosed in the present invention has high strength, high toughness, fatigue resistance, lamellar tearing resistance, good weldability and corrosion resistance, and can meet the long-term service requirements of pressure steel pipes in large-scale high-head power stations.
  • the high-strength steel obtains a single structure through single-phase austenite quenching, which has a significant effect on improving strength and toughness; during the heat treatment process, it is necessary to fully austenitize to ensure hardenability, and to avoid excessive grain growth that affects low-temperature impact toughness.
  • the first quenching increases the quenching temperature to ensure that carbides and alloy elements are fully austenitized, laying a good foundation for organizational homogenization.
  • the second quenching is critical zone quenching to ensure that austenitization is completed while preventing excessive grain growth.
  • high-temperature tempering is used to fully eliminate stress, and a uniform and fine bainite tempering structure is obtained to improve impact toughness and uniformity of overall plate strength.
  • the thickness of the steel ingot is 960-990 mm
  • the pouring temperature is controlled at 1555-1560° C.
  • a heating wire is fed into the center pouring pipe during the pouring process at a feeding speed of 10-20 m/min. It is believed that, without being bound by any theory, by feeding the heating wire into the center pouring pipe during the pouring process, the addition of rare earth elements to the molten steel is beneficial to the modification of inclusions and the purification of the molten steel, thereby improving the internal quality of the ingot.
  • the molten steel is obtained through molten iron pretreatment, converter smelting, argon blowing treatment, VD decarburization, LF refining and VD refining.
  • step 2 when the steel is charged for heating, the furnace temperature is ⁇ 750°C, and before heating, The steel is stewed for 2 to 4 hours before the ingot is formed. It is believed that, without being bound by any theory, the temperature difference between the furnace temperature and the ingot temperature can be reduced by stewing the steel, thereby reducing the stress caused by the temperature difference between the inside and outside of the ingot.
  • step 2 the steel ingot obtained in step 1 is heated once, wherein the target holding temperature of the high temperature section is 1220-1240°C, the holding time is 16-18 hours, and the total heating time is 10-20 min/cm. It is believed that, without any theoretical constraints, by sufficiently high heating temperature, alloy elements such as Ni, Cr, Cu and carbides such as Mo are fully dissolved to achieve a single austenite structure, which is easy to deform, but the temperature cannot be too high, which will cause the austenite grains to grow; and by reasonably controlling the upper temperature limit, it can be avoided that the heating temperature is too high to promote the growth of austenite grains, resulting in the subsequent grains can only be refined on the basis of coarsening.
  • the target holding temperature of the high temperature section is 1220-1240°C
  • the holding time is 16-18 hours
  • the total heating time is 10-20 min/cm.
  • the one-time heating process disclosed in the present invention is adopted; at the same time, the steel is turned over before steel is tapped to ensure that the steel ingot is evenly burned through, and at the same time, the surface oxide scale is ensured to be easy to remove; better results can be obtained.
  • step 3 the steel ingot heated in step 2 is subjected to bloom rolling to obtain a steel plate, wherein the starting rolling temperature is 1050-1100° C., the pass reduction is 60-70 mm, and the temperature of the steel plate after rolling is controlled at 950-980° C. It is believed that, without being bound by any theory, bloom rolling using “high temperature, low speed, and large reduction” promotes effective welding of looseness inside the steel plate, sufficient crushing of the cast structure, and uniform grain refinement of the steel plate.
  • the secondary rolling further includes a slab cutting operation.
  • the intermediate slab is cut into four pieces and then placed in a soaking pit.
  • the four cuttings of the intermediate blank refer to cutting the head, cutting the tail, and cutting the two sides, which is to cut off the irregular or useless edge materials, which is more convenient for subsequent work, and is also beneficial to reduce the reprocessing of waste edge materials and reduce costs.
  • step 5 the secondary product rolling does not need to be widened again, but is directly extended to the finished product thickness.
  • step 5 high-pressure water is used for cooling before the secondary rolling, and rolling is started after the surface of the steel plate has fully turned red.
  • the total time of the secondary rolling is 3 to 4 minutes.
  • step 5 after the secondary rolling is completed, ACC water cooling is turned on twice to reduce the surface and core temperatures of the steel plate to the non-recrystallization zone; optionally, the water entry temperature of the steel plate is 900-950°C, and the red-return temperature of the steel plate is 800-830°C.
  • step 6 the heating temperature of the high temperature quenching is 920-940°C, the heating time is 2-3 min/mm, and the quenching water temperature is 15-18°C.
  • the critical quenching heating temperature is 860-870°C, the heating time is 2-3 min/mm, and the quenching water temperature is 15-18°C;
  • the tempering treatment is tempering in a quenching furnace at 650 ⁇ 20° C. and air cooling to room temperature.
  • the present disclosure also provides a method for producing the high-strength HY950CF steel plate for hydropower engineering.
  • the method comprises the following steps: ingot casting, primary heating, blank rolling, secondary heating and rolling, heat treatment, and includes,
  • the thickness of the ingot body is 960-990mm
  • the pouring temperature is controlled at 1555-1560°C
  • the hot wire is fed into the center pouring pipe during the pouring process, and the wire feeding speed is 10-20m/min;
  • the starting rolling temperature is 1050-1100°C
  • the pass reduction is 60-70mm
  • the billet is 400mm thick
  • the temperature of the steel plate is controlled at 950-980°C after rolling
  • Secondary heating and rolling process the intermediate billet is cut four times and then placed in a soaking pit.
  • the target temperature of the high temperature section is 1220-1240°C, and the total holding time is 5-6 hours. No need to widen again during the secondary rolling, and it can be directly extended to the finished product thickness.
  • the pass reduction is ⁇ 30 ⁇ 5mm
  • the start rolling temperature is ⁇ 1020°C
  • the final rolling temperature is ⁇ 950°C.
  • High-pressure water is used for cooling during the rolling process. Rolling can only be started after the surface of the steel plate has fully returned to red.
  • the total rolling time is controlled within 3-4 minutes.
  • ACC is turned on for two times of water cooling to quickly reduce the surface and core temperature of the steel plate to the non-recrystallization zone.
  • the water entry temperature is 900-950°C
  • the return to red temperature is 800-830°C.
  • Heat treatment process adopt high temperature quenching + critical quenching + tempering heat treatment, among which the high temperature quenching heating temperature is 920 ⁇ 940°C, the heating time is 2.4min/mm, and the quenching machine is cooled to room temperature after the hot steel plate is taken out of the furnace, and the water temperature is 15 ⁇ 18°C; the critical quenching heating temperature is 860 ⁇ 870°C, the heating time is 2.4min/mm, and the quenching machine is cooled to room temperature after the hot steel plate is taken out of the furnace, and the water temperature is 15 ⁇ 18°C; after quenching, it is loaded into the quenching furnace for tempering at 650 ⁇ 20°C, and air-cooled to room temperature.
  • the high temperature quenching heating temperature is 920 ⁇ 940°C
  • the heating time is 2.4min/mm
  • the quenching machine is cooled to room temperature after the hot steel plate is taken out of the furnace, and the water temperature is 15 ⁇ 18°C
  • the critical quenching heating temperature is 860
  • the present disclosure also provides a method for producing the steel plate, the method comprising the following steps:
  • Ingot casting, primary heating, billet rolling, secondary heating and rolling, heat treatment including:
  • the thickness of the ingot body is 960-990mm
  • the pouring temperature is controlled at 1555-1560°C
  • the heating wire is fed into the center pouring pipe during the pouring process to improve the internal quality
  • the wire feeding speed is 15m/min
  • the billet rolling process adopts "high temperature, low speed, and large reduction", the starting rolling temperature is 1050-1100°C, the pass reduction is 60-70mm, the billet is opened to 400mm thick, and the temperature of the steel plate is controlled at 950-980°C after rolling;
  • Secondary heating and rolling process the intermediate billet is cut four times and then placed in a soaking pit.
  • the target temperature of the high temperature section is 1220-1240°C, and the total holding time is 5-6 hours. No need to widen again during the secondary rolling, and it can be directly extended to the finished product thickness.
  • the pass reduction is ⁇ 30 ⁇ 5mm
  • the start rolling temperature is ⁇ 1020°C
  • the final rolling temperature is ⁇ 950°C.
  • High-pressure water is used for cooling during the rolling process. Rolling can only be started after the surface of the steel plate has fully returned to red.
  • the total rolling time is controlled within 3-4 minutes.
  • ACC is turned on for water cooling twice to quickly reduce the surface and core temperature of the steel plate to the non-recrystallization zone.
  • the water temperature is 900-950°C. Red return temperature 800 ⁇ 830°C;
  • Heat treatment process adopt high temperature quenching + critical quenching + tempering heat treatment, wherein the first quenching heating temperature is 920 ⁇ 940°C, the heating time is 2.4min/mm, and the quenching machine is cooled to room temperature after the hot steel plate is out of the furnace, and the water temperature is 15 ⁇ 18°C; the second quenching heating temperature is 860 ⁇ 870°C, the heating time is 2.4min/mm, and the quenching machine is cooled to room temperature after the hot steel plate is out of the furnace, and the water temperature is 15 ⁇ 18°C; after quenching, it is loaded into the quenching furnace for tempering at 650 ⁇ 20°C and air-cooled to room temperature.
  • the present disclosure also provides a steel plate prepared according to the aforementioned method.
  • the steel plate is a high-strength HY950CF steel plate for hydropower engineering, the thickness of the steel plate is 50 to 120 mm, and contains the following chemical components in mass percentage (unit, wt%):
  • the steel plate has a carbon equivalent Ceq ⁇ 0.7, a bainite tempered structure, and a -60°C longitudinal and transverse V-type impact energy ⁇ 127J.
  • the present disclosure provides that in one embodiment, the method for producing a steel plate of the present disclosure comprises the following steps: ingot casting, primary heating, slab rolling, secondary heating, rolling and heat treatment, as follows:
  • the thickness of the ingot body is 960-990mm
  • the pouring temperature is controlled at 1555-1560°C
  • a heating wire is fed into the center pouring pipe during the pouring process to improve the internal quality.
  • the wire feeding speed is 15m/min.
  • Rare earth elements are added to the molten steel to facilitate the denaturation of inclusions and purification of the molten steel;
  • the furnace temperature is ⁇ 750°C when loading steel, and the steel is stewed for 2 to 4 hours to reduce the temperature difference between the furnace temperature and the ingot, and reduce the stress caused by the temperature difference between the inside and outside of the ingot.
  • the target insulation temperature of the high temperature section is 1220-1240°C, the insulation time is 16-18 hours, and the total heating time is 15min/cm; in order to effectively play the role of elements such as Ni, Cr, Cu, and Mo, a sufficiently high heating temperature is required to fully dissolve alloy elements such as Ni, Cr, Cu, and carbides such as Mo to achieve a single austenite structure, which is prone to deformation, but excessive heating temperature promotes the growth of austenite grains; and by reasonably controlling the upper temperature limit, it can be avoided that the heating temperature is too high to promote the growth of austenite grains, resulting in the subsequent grains can only be refined on the basis of coarsening.
  • the above-mentioned one-time heating process is adopted; at the same time, the steel is turned over before steelmaking to ensure that the ingot is evenly burned through and that the surface oxide scale is easy to remove;
  • the billet rolling process adopts "high temperature, low speed and large reduction", the rolling temperature is 1050-1100°C, the pass reduction is 60-70mm, which promotes the effective welding of internal looseness, the full crushing of the cast structure, and the uniform refinement of the steel plate grains.
  • the billet is opened to a thickness of 400mm, and the temperature of the steel plate is controlled at 950-980°C at the end of rolling;
  • Secondary heating and rolling process the intermediate billet is cut into four pieces and then placed in a soaking pit.
  • the target temperature of the high temperature section is 1220-1240°C, and the total holding time is 5-6 hours. There is no need to widen the product again during the secondary rolling process. It can be directly extended to the finished product thickness.
  • the pass reduction is ⁇ 30 ⁇ 5mm to ensure that the deformation penetrates to 1/2 of the thickness to promote further grain refinement.
  • the starting rolling temperature is ⁇ 1020°C
  • the final rolling temperature is ⁇ 1020°C.
  • Temperature ⁇ 950°C high-pressure water is used for cooling during rolling. Rolling can only be started after the surface of the steel plate is fully red. The total rolling time is controlled within 3-4 minutes.
  • ACC is turned on for water cooling twice to quickly reduce the surface and core temperature of the steel plate to the non-recrystallization zone.
  • the water temperature is 900-950°C and the red-returning temperature is 800-830°C. Rapid cooling is conducive to reducing the temperature difference between the center area and the surface of the steel plate thickness, inhibiting the growth and recrystallization of austenite grains, and promoting grain refinement and grain uniformity.
  • Heat treatment process adopt high temperature quenching + critical quenching + tempering heat treatment, wherein the first quenching heating temperature is 920 ⁇ 940°C, the heating time is 2.4min/mm, and the quenching machine is cooled to room temperature after the hot steel plate is out of the furnace, and the water temperature is 15 ⁇ 18°C; the second quenching heating temperature is 860 ⁇ 870°C, the heating time is 2.4min/mm, and the quenching machine is cooled to room temperature after the hot steel plate is out of the furnace, and the water temperature is 15 ⁇ 18°C; after quenching, it is loaded into the quenching furnace for tempering at 650 ⁇ 20°C and air-cooled to room temperature.
  • the 50-120 mm thick high-strength hydropower HY950CF steel plate provided by the present invention has high low-temperature impact toughness, weldability and corrosion resistance. It should be noted that the high-strength steel obtains a single structure through single-phase austenite quenching, which has obvious effects on improving strength and toughness.
  • the first quenching increases the quenching temperature to ensure that carbides and alloy elements are fully austenitized, laying a good foundation for organizational homogenization.
  • the second quenching is critical zone quenching to ensure that austenitization is completed while preventing excessive grain growth.
  • the stress is fully eliminated through high-temperature tempering to obtain a uniform and fine bainite tempering structure, thereby improving the impact toughness and the uniformity of the strength of the entire plate.
  • the invention discloses a new composition design, reasonably controls the amount of hardenability elements added, and obtains a 100% bainite tempered structure after heat treatment; combines the disclosed rare earth element addition process to achieve steel liquid purification and modified inclusions, effectively improving the low-temperature impact toughness of rare earth steel; adopts a new steel plate forming process to increase the ingot thickness, increase the rolling compression ratio, and improve the ingot heating and rolling process to ensure that the internal quality of the steel plate reaches the level of forgings, and replaces forging with rolling; in the heat treatment process, multiple quenchings are performed through high and low matching to ensure hardenability while refining the austenite grains, and the uniformity of the mechanical properties of the whole plate is improved through improved tempering.
  • a 50-120 mm thick high-strength hydropower HY950CF steel plate is produced, which contains the following chemical components in mass percentage (unit, wt%): C: 0.09-0.12, Si: 0.15-0.25, Mn: 0.30-0.60, P ⁇ 0.010, S ⁇ 0.003, Als: 0.020-0.040, Nb: 0.02-0.03, V: 0.04-0.1, Cr: 1.2-1.6, Ni: 2.4-2.8, Cu: 0.8-1.0, Mo: 0.2-0.3, Re: 0.0015-0.0025, and the rest are Fe and residual elements.
  • the production method includes the following process flow: KR hot metal pretreatment, converter smelting, argon blowing treatment, VD decarburization, LF refining, VD refining, casting process, ingot cleaning and coating, billet heating and rolling, secondary heating and rolling, and heat treatment.
  • KR hot metal pretreatment converter smelting
  • argon blowing treatment VD decarburization
  • LF refining VD refining
  • casting process ingot cleaning and coating
  • billet heating and rolling secondary heating and rolling
  • secondary heating and rolling and heat treatment.
  • KR hot metal pretreatment process the slag must be cleaned before the hot metal arrives at the station to ensure that the slag layer thickness on the liquid surface is ⁇ 25mm.
  • the sulfur content of the hot metal after KR treatment is controlled below 0.005%, and the desulfurization temperature drop is ⁇ 25°C;
  • Converter smelting S ⁇ 0.005% and P ⁇ 0.050% of molten iron in the furnace, and the temperature of molten iron ⁇ 1280°C.
  • the scrap steel added to the converter must be dry high-quality scraps and special scrap steel containing nickel.
  • the loading amount of the converter is controlled according to the remaining 6-8 tons of steel casting.
  • the tapping temperature is ⁇ 1600°C, 0.04% ⁇ C ⁇ 0.07%, and P ⁇ 0.007%.
  • the slag is blocked by a slag cone after tapping. If the slag blocking fails, the furnace must be lifted in advance to ensure that the thickness of the converter slag is controlled below 20mm to avoid the slag returning to P;
  • VD decarburization Ensure that the VD temperature of the molten steel is ⁇ 1540°C. After the molten steel falls into the VD furnace, add carbon powder appropriately according to the C content of the steel, and then cover the cover for vacuum operation. During the vacuum stage of the VD furnace, the amount of argon should be increased to fully achieve the purpose of vacuum decarburization.
  • the pressure holding time should be ⁇ 10min, and the leaving station temperature should be ⁇ 1535°C;
  • LF refining slag making according to the large slag process standard, lime addition amount is 1000-1200 kg, basicity is controlled at 4.5-6.5, after heating for 3 minutes, first add 50 kg calcium carbide, then add 20-40 kg aluminum particles, and then add 2-4 shovels of aluminum particles to the ladle with a shovel every 2 minutes to ensure that the slag turns white; in the second heating, add 10-30 kg calcium carbide each time according to the arc effect, and add 1-3 shovels of aluminum particles to the ladle with a shovel every 2 minutes to ensure that the slag is maintained white throughout the second heating process; in the third heating, add deoxidizer according to the color of the slag to maintain the white slag; the white slag is required to be kept for 25-35 minutes during the refining process;
  • VD refining VD pressure holding time is controlled to be ⁇ 18min, and the molten steel should be tumbling well under the vacuum degree of 67Pa during the pressure holding process, and the H content is required to be ⁇ 1.0PPm; after breaking the air, rice husk is added in time for soft blowing for 5-8min, and then the bag is prepared to leave the station, and the leaving station temperature is controlled at about 1578-1583°C;
  • the temperature of the insulation cap is greater than 160°C, and a 45-ton fixed-thickness and width-adjustable water-cooled steel ingot mold is used.
  • the thickness of the steel ingot body is 960-990mm, the width is 2150mm, and the height is 2730mm.
  • all resistant auxiliary materials must be dried, and the pouring system must be dried and clean.
  • the water-cooled mold used must ensure the taper (30mm) and an extrusion mechanism is set on the side to extrude the wide side of the ingot in the later stage of solidification, and efficiently fit the cooling to form a dense structure.
  • the steel ingot cap mouth adopts effective Insulation measures are taken to form a shrinkage channel with a larger top and a smaller bottom inside the ingot during the solidification process; the pouring temperature is controlled at 1555-1560°C; after the molten steel arrives at the station, the temperature is appropriate (within the standard upper limit - upper limit + 3°C) and the molten steel is calmed and the temperature is measured to confirm that it meets the pouring requirements before pouring; if the temperature of the molten steel at the station does not meet the above standards, soft argon blowing is immediately carried out, and after the argon blowing is completed, it is required to calm for 5 minutes before pouring.
  • the model RECe-48 is fed into the middle pouring pipe, and the wire feeding speed is 15m/min. After the pouring is completed, the cap insulation effect must be ensured.
  • Billet heating and rolling The total heating time of the ingot is 15min/cm, the furnace temperature is ⁇ 750°C when loading steel, and the steel is stewed for 2 to 4 hours to reduce the temperature difference between the furnace temperature and the ingot, and reduce the stress difference caused by the temperature difference between the inside and outside of the ingot.
  • the target insulation temperature of the high temperature section is 1220 ⁇ 1240°C, and the insulation time is 16 to 18 hours; the rolling process adopts "high temperature, low speed, and large pressure reduction", and the starting rolling temperature is 1050 ⁇ 1100°C, give full play to the large rolling force advantage of the 3800mm rolling mill, control the single-pass reduction at 60-70mm, ensure that the deformation penetrates to 1/2 of the thickness, achieve effective welding of the loose inside of the ingot, fully break the cast structure, and promote uniform grain refinement of the steel plate.
  • the billet specification is 400 ⁇ 2200 ⁇ L mm, and it is released when the rolling thickness is 400mm.
  • the rolling end temperature is 950-980°C;
  • Heat treatment In order to effectively improve the strength and ensure the low-temperature impact toughness, a two-time quenching + tempering heat treatment process is adopted.
  • the quenching machine After the hot steel plate is taken out of the furnace, the quenching machine is cooled to room temperature, and the water temperature is 15-18°C; after quenching, it is loaded into the quenching furnace for tempering at 650 ⁇ 20°C, and air-cooled to room temperature and then sampled for detection.
  • Table 1 shows the test results:
  • the chemical composition, mechanical properties test specimen sampling location and specimen preparation of the steel plate are carried out in accordance with the standard GB/T 2975 mechanical properties test sampling location and specimen preparation regulations.
  • the low temperature impact toughness test is carried out in accordance with the GB/T 229 standard, and the tensile properties test is carried out in accordance with the GB/T228 standard.
  • the mechanical properties and metallographic structure of the steel plate in the supply state are comprehensively inspected.
  • the developed steel plate has a 100% genuine product rate in external inspection, and the final steel plate flaw detection meets the Level I flaw detection requirements of GB/T 2970 "Super-thick steel plate inspection method".
  • the present invention provides a high-strength HY950CF steel plate for hydropower engineering and a preparation method thereof.
  • the method disclosed herein is beneficial to the purification of molten steel, the removal of deteriorated inclusions, and the low-temperature impact toughness of steel by adding rare earth elements.
  • the steel plate obtained by the present invention has high strength, high toughness, fatigue resistance, lamellar tearing resistance, good weldability and corrosion resistance, and can meet the long-term service requirements of pressure steel pipes in large-scale high-head power stations, so it has excellent practicality.

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Abstract

本公开属于中厚板生产领域，具体涉及一种高强度水电工程用HY950CF钢板及其生产方法，所述钢板的化学成分包含C、Si、Mn、P、S、Als、Nb、V、Cr、Ni、Cu、Mo、Re、Fe及残留元素，稀土元素的加入有利于钢液净化、变质夹杂物，钢的低温冲击韧性；合理控制淬透性元素加入量，并经过热处理后可得到100％的贝氏体回火组织；采用大厚度钢锭生产，提高轧制压缩比，以及改进钢锭加热轧制工艺，实现以轧代锻；热处理环节通过多次淬火，保证淬透性的同时细化奥氏体晶粒，并通过回火提高整板力学性能的均匀性。获得的钢板具有高强度、高韧性、抗疲劳、抗层状撕裂性能，以及良好的焊接性及耐腐蚀性能，能满足在大型高水头电站压力钢管长期服役使用要求。

Description

一种高强度水电工程用HY950CF钢板及其生产方法
相关申请的交叉引用
本申请要求于2022年11月26日提交中国专利局的申请号为202211494963.2、名称为“一种高强度水电工程用HY950CF钢板及其生产方法”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本公开属于中厚板生产领域，具体涉及到一种高强度水电工程用HY950CF钢板及其生产方法。
背景技术
目前，长江上游干流及金沙江、大渡河已经或即将建设的大型高水头电站项目共有33个，500万kW以上的水电站有向家坝、溪洛渡、白鹤滩、乌东德、龙盘峡等。目前压力钢管的最高水头已达到1200m，高强钢管壁厚度已达90mm，高强钢月牙肋厚已为150mm，HD值(H指蜗壳承受的内压水头，D指蜗壳进口断面的直径)已超过4700m2。
应用于工程的相应材料不断更新换代，800MPa高强钢已经在水电领域普遍使用，1000MPa新材料的研究开发迫在眉睫且意义重大。
发明内容
本公开提供了一种高强度水电工程用HY950CF钢板，所述钢板的厚度为50～120mm，包含如下质量百分比的化学成分：
C：0.09～0.12wt％、Si：0.15～0.25wt％、Mn：0.30～0.60wt％、P≤0.010wt％、S≤0.003wt％、Als：0.020～0.040wt％、Nb：0.02～0.03wt％、V：0.04～0.1wt％、Cr：1.2～1.6wt％、Ni：2.4～2.8wt％、Cu：0.8～1.0wt％、Mo：0.2～0.3wt％、Re：0.0015～0.0025wt％，其它为Fe和残留元素。
本公开还提供了一种高强度水电工程用HY950CF钢板，所述钢板的厚度为50～120mm，包含如下质量百分比的化学成分：
C：0.09～0.12wt％、Si：0.15～0.25wt％、Mn：0.30～0.60wt％、P≤0.010wt％、S≤0.003wt％、Als：0.020～0.040wt％、Nb：0.02～0.03wt％、V：0.04～0.1wt％、Cr：1.2～1.6wt％、Ni：2.4～2.8wt％、Cu：0.8～1.0wt％、Mo：0.2～0.3wt％、Re： 0.0015～0.0025wt％，其它为Fe和残留元素，碳当量Ceq＜0.7，组织为贝氏体回火组织，‐60℃纵横向V型冲击功≥127J。
本公开还提供了一种钢板的生产方法，所述方法包括以下步骤：
步骤1.将钢水经浇铸得到钢锭，其中，所述浇铸中加入Re丝；
步骤2.对步骤1得到的钢锭进行一次加热，其中，高温段目标保温温度1220～1240℃，保温时间16～18小时；
步骤3.对步骤2加热后的钢锭进行开坯轧制，得到钢板，其中，开轧温度1050～1100℃，道次压下量60～70mm，轧制结束钢板温度控制在950～980℃；
步骤4.对步骤3得到的钢板进行二次加热，其中，高温段目标保温温度1220～1240℃、保温时间5～6小时；
步骤5.对步骤4加热后的钢板进行二次轧制，其中，道次压下量≥30±5mm，开轧温度≥1020℃，终轧温度≤950℃，轧制完毕后，将钢板表面及心部温度降至未再结晶区；
步骤6.将步骤5得到的钢板进行热处理，其中所述钢板依次进行高温淬火处理、临界淬火处理和回火处理；并且所述高温淬火加热温度920～940℃，所述临界淬火加热温度860～870℃，所述回火处理温度650±20℃；
步骤7.将步骤6的钢板冷却至常温，即得。
可选地，在步骤1中，所述钢锭的本体厚度960～990mm，浇注温度按照1555～1560℃进行控制，浇注过程向中注管内加喂Re丝，喂丝速度10-20m/min。
可选地，在步骤1中，经过铁水预处理、转炉冶炼、吹氩处理、VD脱碳、LF精炼和VD精炼，得到所述钢水。
可选地，在步骤2中，装钢以进行加热时，炉膛温度≤750℃，并在加热之前焖钢2～4小时。
可选地，在步骤2中，总加热时间10-20min/cm。
可选地，在步骤4中，所述二次轧制还包含切坯操作，可选地，中间坯四切后装均热坑。
可选地，在步骤5中，所述二次成材轧制时无需再次展宽，直接展长至成品厚度。
可选地，在步骤5中，在二次轧制之前，使用高压水降温，待钢板表面充分返红后方开始轧制。
可选地，二次轧制总时间3～4分钟。
可选地，在步骤5中，二次轧制完毕后，开启ACC入水冷却两遍以将钢板表面及心部温度降至未再结晶区；可选地，所述钢板的入水温度900～950℃、所述钢板的返红温度800～830℃。
可选地，在步骤6中，所述高温淬火的加热温度920～940℃，加热时间2～3min/mm，淬火用水温度15～18℃。
可选地，在步骤6中，所述临界淬火的加热温度860～870℃，加热时间2～3min/mm，淬火用水温度15～18℃；
可选地，在步骤6中，所述回火处理为淬火炉650±20℃回火，空冷至常温。
本公开还提供了所述高强度水电工程用HY950CF钢板生产方法，
所述方法包括以下步骤：钢锭浇铸、一次加热、开坯轧制、二次加热及轧制、热处理，并包含，
a.钢锭浇铸，钢锭本体厚度960～990mm，浇注温度按照1555～1560℃进行控制，浇注过程向中注管内加喂Re丝，喂丝速度10～20m/min；
b.一次加热工艺，装钢时炉膛温度≤750℃，焖钢2～4小时，高温段目标保温温度1220～1240℃、保温时间16～18小时，总加热时间10～20min/cm；
c.开坯轧制工艺，开轧温度1050～1100℃，道次压下量60～70mm，开坯至400mm厚，轧制结束钢板温度控制在950～980℃；
d.二次加热及轧制工艺，中间坯四切后装均热坑，高温段目标温度1220～1240℃、总保温时间5～6小时，二次成材轧制时无需再次展宽，直接展长至成品厚度，道次压下量≥30±5mm，开轧温度≥1020℃，终轧温度≤950℃，轧制过程中使用高压水降温，待钢板表面充分返红后方可开始轧制，轧制总时间控制在3～4分钟，轧制完毕开启ACC入水冷却两遍快速将钢板表面及心部温度降至未再结晶区，入水温度900～950℃、返红温度800～830℃；
e.热处理工艺，采用高温淬火+临界淬火+回火热处理，其中高温淬火加热温度920～940℃，加热时间2.4min/mm，热态钢板出炉后淬火机冷却至常温，水温15～18℃；临界淬火加热温度860～870℃，加热时间2.4min/mm，热态钢板出炉后淬火机冷却至常温，水温15～18℃；淬火后装入淬火炉650±20℃回火，空冷至常温，即得。
本公开还提供了一种所述钢板的生产方法，所述方法包括以下步骤：
钢锭浇铸、一次加热、开坯轧制、二次加热及轧制、热处理，包括：
a.钢锭浇铸，钢锭本体厚度960～990mm，浇注温度按照1555～1560℃进行控制，浇注过程向中注管内加喂Re丝改善内部质量，喂丝速度15m/min；
b.一次加热工艺，装钢时炉膛温度≤750℃，焖钢2～4小时以减少炉温与钢锭的温差，降低钢锭内外温差导致的应力，高温段目标保温温度1220～1240℃、保温时间16～18小时，总加热时间15min/cm；
c.开坯轧制工艺，采用“高温、低速、大压下”，开轧温度1050～1100℃，道次压 下量60～70mm，开坯至400mm厚，轧制结束钢板温度控制在950～980℃；
d.二次加热及轧制工艺，中间坯四切后装均热坑，高温段目标温度1220～1240℃、总保温时间5～6小时，二次成材轧制时无需再次展宽，直接展长至成品厚度，道次压下量≥30±5mm，开轧温度≥1020℃，终轧温度≤950℃，轧制过程中使用高压水降温，待钢板表面充分返红后方可开始轧制，轧制总时间控制在3～4分钟，轧制完毕开启ACC入水冷却两遍快速将钢板表面及心部温度降至未再结晶区，入水温度900～950℃、返红温度800～830℃；
e.热处理工艺，采用高温淬火+临界淬火+回火热处理，其中第一次淬火加热温度920～940℃，加热时间2.4min/mm，热态钢板出炉后淬火机冷却至常温，水温15～18℃；第二次淬火加热温度860～870℃，加热时间2.4min/mm，热态钢板出炉后淬火机冷却至常温，水温15～18℃；淬火后装入淬火炉650±20℃回火，空冷至常温。
本公开还提供了根据前述方法制备的钢板。
可选地，所述钢板为高强度水电工程用HY950CF钢板，所述钢板的厚度为50～120mm，包含如下质量百分比的化学成分(单位，wt％)：
C：0.09～0.12、Si：0.15～0.25、Mn：0.30～0.60、P≤0.010、S≤0.003、Als：0.020～0.040、Nb：0.02～0.03、V：0.04～0.1、Cr：1.2～1.6、Ni：2.4～2.8、Cu：0.8～1.0、Mo：0.2～0.3、Re：0.0015～0.0025，其它为Fe和残留元素；
可选地，所述钢板碳当量Ceq＜0.7，组织为贝氏体回火组织，‐60℃纵横向V型冲击功≥127J。
附图说明
图1为本公开实施方式中，120mm厚钢板截面的金相组织示意图(金相显微镜，×100)。
图2为本公开实施方式中，120mm厚钢板截面的金相组织示意图(金相显微镜，×200)。
图3为本公开实施方式中，120mm厚钢板截面的金相组织示意图(金相显微镜，×500)。
具体实施方式
术语定义：
如本文所用，除非特别指出，本文中所使用Als意指酸溶铝。
在工程中使用1000MPa高强钢材料，减少壁厚的同时也能减轻构件重量，降低施工难度，更减少了材料的使用量，在节能减排方面有着显著效果。
中国专利CN 114395731 A公开了一种水电工程用低焊接裂纹敏感性止裂钢HY950CF，该钢板的厚度为20～100mm，组织为保留马氏体位向的回火索氏体组织，包 含如下质量百分比的化学成分(单位，wt％)：C 0.06～0.15、Si≤0.20、Mn 0.7～1.5、P≤0.008、S≤0.001、Als 0.015～0.060、V≤0.05、Cr 0.5～0.8、Ni 1.5～4.0、Mo 0.4～0.8、Nb≤0.04、B0.0008～0.0015，其它为Fe和残留元素；所述钢板的交货状态为调质，即在线淬火+回火处理。该公开的优点是采用合理的成分配比实现钢板强韧性匹配，板子薄，采用连铸成材，但随着高水头大型水电站项目陆续开工建设，目前钢板厚度及强度级别已无法满足使用要求。
中国专利CN 105925887A公开了一种980MPa级热轧铁素体贝氏体双相钢，其化学成分重量百分比为：C：0.15～0.30％，Si0.8～2.0％，Mn：1.0～2.0％，P≤0.02％，S≤0.005％，O≤0.003％，Al0.5～1.0％，N≤0.006％，Nb：0.01～0.06％，Ti：0.01～0.05％，其余为Fe和不可避免的杂质，且上述元素同时需满足如下关系：0.05％≤Nb+Ti≤0.10％，2.5≤Al/C≤5.0。该公开的特点是采用高碳高锰成分设计，钢板厚度3～6mm，缺点是碳当量较高，可焊接性能差。
本公开提供一种高强度水电工程用HY950CF钢板及其生产方法。
本公开提供了一种高强度水电工程用HY950CF钢板，所述钢板的厚度为50～120mm，包含如下质量百分比的化学成分：
C：0.09～0.12wt％、Si：0.15～0.25wt％、Mn：0.30～0.60wt％、P≤0.010wt％、S≤0.003wt％、Als：0.020～0.040wt％、Nb：0.02～0.03wt％、V：0.04～0.1wt％、Cr：1.2～1.6wt％、Ni：2.4～2.8wt％、Cu：0.8～1.0wt％、Mo：0.2～0.3wt％、Re：0.0015～0.0025wt％，其它为Fe和残留元素。
本公开还提供了一种高强度水电工程用HY950CF钢板，所述钢板的厚度为50～120mm，包含如下质量百分比的化学成分：
C：0.09～0.12wt％、Si：0.15～0.25wt％、Mn：0.30～0.60wt％、P≤0.010wt％、S≤0.003wt％、Als：0.020～0.040wt％、Nb：0.02～0.03wt％、V：0.04～0.1wt％、Cr：1.2～1.6wt％、Ni：2.4～2.8wt％、Cu：0.8～1.0wt％、Mo：0.2～0.3wt％、Re：0.0015～0.0025wt％，其它为Fe和残留元素，碳当量Ceq＜0.7，组织为贝氏体回火组织，‐60℃纵横向V型冲击功≥127J。
本公开的HY950CF钢板，采用Nb、V、Cu、Cr、Ni、Mo多种元素微合金化，从而保证了HY950CF满足高强度、较高的低温冲击韧性、可焊接性、耐腐蚀性能等多项特殊要求。据信，不收任何理论的约束，增加镍含量既能强烈提高特厚板钢板的强度，又能促进其韧性保持在较高水平；铬碳化物是各种碳化物中最小的一种，它可以均匀地分布在钢体中，提高Cr含量对于提高强度、硬度、耐磨性有突出贡献；低碳设计有利于提高低温冲击韧性；Nb、V、Ti等微合金元素对韧性、强度以及可焊性都至关重要，促进在热处理工艺中形成 各类M(C、N)纳米析出相；加入微量稀土元素具有净化钢液、变质夹杂物的作用，可提升稀土钢的低温冲击韧性。进一步地，通过合理控制淬透性元素加入量，并经过热处理后得到100％贝氏体回火组织；结合本公开的稀土元素加入方法，实现钢液净化、变质夹杂物，从而有效提升了稀土钢的低温冲击韧性。
本公开还提供了一种钢板的生产方法，所述方法包括以下步骤：
步骤1.将钢水经浇铸得到钢锭，其中，所述浇铸中加入Re丝；
步骤2.对步骤1得到的钢锭进行一次加热，其中，高温段目标保温温度1220～1240℃，保温时间16～18小时；
步骤3.对步骤2加热后的钢锭进行开坯轧制，得到钢板，其中，开轧温度1050～1100℃，道次压下量60～70mm，轧制结束钢板温度控制在950～980℃；
步骤4.对步骤3得到的钢板进行二次加热，其中，高温段目标保温温度1220～1240℃、保温时间5～6小时；
步骤5.对步骤4加热后的钢板进行二次轧制，其中，道次压下量≥30±5mm，开轧温度≥1020℃，终轧温度≤950℃，轧制完毕后，将钢板表面及心部温度降至未再结晶区；
步骤6.将步骤5得到的钢板进行热处理，其中所述钢板依次进行高温淬火处理、临界淬火处理和回火处理；并且所述高温淬火加热温度920～940℃，所述临界淬火加热温度860～870℃，所述回火处理温度650±20℃；
步骤7.将步骤6的钢板冷却至常温，即得。
本公开的方法获得的钢板具有高强度、高韧性、抗疲劳、抗层状撕裂性能，以及良好的焊接性及耐腐蚀性能，能满足在大型高水头电站压力钢管长期服役使用要求。其中，高强钢通过单相奥氏体淬火获得单一组织对于提升强度、改善韧性的效果明显；热处理过程中既要完全奥氏体化保证淬透性，又要避免晶粒过分长大影响低温冲击韧性，第一次淬火提高淬火温度，保证碳化物及合金元素充分奥氏体化，为组织均匀化打好基础，第二次淬火为临界区淬火，保证完成奥氏体化的同时防止晶粒过分长大，最终通过高温回火充分消除应力，得到组织均匀细小的贝氏体回火组织，提高冲击韧性及整板强度均匀性。
在一些实施方式中，在步骤1中，所述钢锭的本体厚度960～990mm，浇注温度按照1555～1560℃进行控制，浇注过程向中注管内加喂Re丝，喂丝速度10-20m/min。据信，不受任何理论约束，通过在浇注过程向中注管内加喂Re丝，钢水中加入稀土元素有利于夹杂物变性、净化钢液，从而改善铸锭的内部质量。
在一些实施方式中，在步骤1中，经过铁水预处理、转炉冶炼、吹氩处理、VD脱碳、LF精炼和VD精炼，得到所述钢水。
在一些实施方式中，在步骤2中，装钢以进行加热时，炉膛温度≤750℃，并在加热之 前焖钢2～4小时。据信，不受任何理论约束，通过焖钢可以减少炉温与钢锭的温差，降低钢锭内外温差导致的应力。
在一些实施方式中，在步骤2中，对步骤1得到的钢锭进行一次加热，其中，高温段目标保温温度1220～1240℃，保温时间16～18小时；总加热时间10-20min/cm。据信，不受任何理论约束，通过足够高的加热温度，使Ni、Cr、Cu等合金元素及Mo等碳化物充分溶解，达到奥氏体单一组织，容易产生变形，但又不能温度过高，温度过高将导致奥氏体晶粒长大；而通过合理控制温度上限，能避免加热温度过高促使奥氏体晶粒长大导致的后序晶粒只能在粗化的基础上细化。因此，结合钢锭的锭型特点，采用本公开的一次加热工艺；同时出钢前翻钢保证钢锭均匀透烧，同时确保表面氧化铁皮易去除；可以获得更优的结果。
在一些实施方式中，在步骤3中，对步骤2加热后的钢锭进行开坯轧制，得到钢板，其中，开轧温度1050～1100℃，道次压下量60～70mm，轧制结束钢板温度控制在950～980℃。据信，不受任何理论约束，采用“高温、低速、大压下”进行开坯轧制，促进钢板内部疏松有效焊合、铸态组织充分破碎、钢板晶粒均匀细化。
在一些实施方式中，在步骤4中，所述二次轧制还包含切坯操作，可选地，中间坯四切后装均热坑。
其中，所述中间坯四切是指切头、切尾、切两边，是将不规则或无用的边料切去，更便于后序工作，也有利于减少废边料的再加工，降低成本。
在一些实施方式中，在步骤5中，所述二次成材轧制时无需再次展宽，直接展长至成品厚度。
在一些实施方式中，在步骤5中，在二次轧制之前，使用高压水降温，待钢板表面充分返红后方开始轧制。
在一些实施方式中，二次轧制总时间3～4分钟。
在一些实施方式中，在步骤5中，二次轧制完毕后，开启ACC入水冷却两遍以将钢板表面及心部温度降至未再结晶区；可选地，所述钢板的入水温度900～950℃、所述钢板的返红温度800～830℃。
在一些实施方式中，在步骤6中，所述高温淬火的加热温度920～940℃，加热时间2～3min/mm，淬火用水温度15～18℃。
在一些实施方式中，在步骤6中，所述临界淬火的加热温度860～870℃，加热时间2～3min/mm，淬火用水温度15～18℃；
在一些实施方式中，在步骤6中，所述回火处理为淬火炉650±20℃回火，空冷至常温。
本公开还提供了所述高强度水电工程用HY950CF钢板生产方法，
所述方法包括以下步骤：钢锭浇铸、一次加热、开坯轧制、二次加热及轧制、热处理，并包含，
a.钢锭浇铸，钢锭本体厚度960～990mm，浇注温度按照1555～1560℃进行控制，浇注过程向中注管内加喂Re丝，喂丝速度10～20m/min；
b.一次加热工艺，装钢时炉膛温度≤750℃，焖钢2～4小时，高温段目标保温温度1220～1240℃、保温时间16～18小时，总加热时间10～20min/cm；
c.开坯轧制工艺，开轧温度1050～1100℃，道次压下量60～70mm，开坯至400mm厚，轧制结束钢板温度控制在950～980℃；
d.二次加热及轧制工艺，中间坯四切后装均热坑，高温段目标温度1220～1240℃、总保温时间5～6小时，二次成材轧制时无需再次展宽，直接展长至成品厚度，道次压下量≥30±5mm，开轧温度≥1020℃，终轧温度≤950℃，轧制过程中使用高压水降温，待钢板表面充分返红后方可开始轧制，轧制总时间控制在3～4分钟，轧制完毕开启ACC入水冷却两遍快速将钢板表面及心部温度降至未再结晶区，入水温度900～950℃、返红温度800～830℃；
e.热处理工艺，采用高温淬火+临界淬火+回火热处理，其中高温淬火加热温度920～940℃，加热时间2.4min/mm，热态钢板出炉后淬火机冷却至常温，水温15～18℃；临界淬火加热温度860～870℃，加热时间2.4min/mm，热态钢板出炉后淬火机冷却至常温，水温15～18℃；淬火后装入淬火炉650±20℃回火，空冷至常温，即得。
本公开还提供了一种所述钢板的生产方法，所述方法包括以下步骤：
钢锭浇铸、一次加热、开坯轧制、二次加热及轧制、热处理，包括：
a.钢锭浇铸，钢锭本体厚度960～990mm，浇注温度按照1555～1560℃进行控制，浇注过程向中注管内加喂Re丝改善内部质量，喂丝速度15m/min；
b.一次加热工艺，装钢时炉膛温度≤750℃，焖钢2～4小时以减少炉温与钢锭的温差，降低钢锭内外温差导致的应力，高温段目标保温温度1220～1240℃、保温时间16～18小时，总加热时间15min/cm；
c.开坯轧制工艺，采用“高温、低速、大压下”，开轧温度1050～1100℃，道次压下量60～70mm，开坯至400mm厚，轧制结束钢板温度控制在950～980℃；
d.二次加热及轧制工艺，中间坯四切后装均热坑，高温段目标温度1220～1240℃、总保温时间5～6小时，二次成材轧制时无需再次展宽，直接展长至成品厚度，道次压下量≥30±5mm，开轧温度≥1020℃，终轧温度≤950℃，轧制过程中使用高压水降温，待钢板表面充分返红后方可开始轧制，轧制总时间控制在3～4分钟，轧制完毕开启ACC入水冷却两遍快速将钢板表面及心部温度降至未再结晶区，入水温度900～950℃、 返红温度800～830℃；
e.热处理工艺，采用高温淬火+临界淬火+回火热处理，其中第一次淬火加热温度920～940℃，加热时间2.4min/mm，热态钢板出炉后淬火机冷却至常温，水温15～18℃；第二次淬火加热温度860～870℃，加热时间2.4min/mm，热态钢板出炉后淬火机冷却至常温，水温15～18℃；淬火后装入淬火炉650±20℃回火，空冷至常温。
本公开还提供了根据前述方法制备的钢板。
可选地，所述钢板为高强度水电工程用HY950CF钢板，所述钢板的厚度为50～120mm，包含如下质量百分比的化学成分(单位，wt％)：
C：0.09～0.12、Si：0.15～0.25、Mn：0.30～0.60、P≤0.010、S≤0.003、Als：0.020～0.040、Nb：0.02～0.03、V：0.04～0.1、Cr：1.2～1.6、Ni：2.4～2.8、Cu：0.8～1.0、Mo：0.2～0.3、Re：0.0015～0.0025，其它为Fe和残留元素；
可选地，所述钢板碳当量Ceq＜0.7，组织为贝氏体回火组织，‐60℃纵横向V型冲击功≥127J。
在一个实施方案中，本公开提供的在一个实施方式中，本公开的钢板的生产方法包括以下步骤：钢锭浇铸、一次加热、开坯轧制、二次加热、轧制及热处理，如下：
a.钢锭浇铸，钢锭本体厚度960～990mm，浇注温度按照1555～1560℃进行控制，浇注过程向中注管内加喂Re丝改善内部质量，喂丝速度15m/min，钢水中加入稀土元素有利于夹杂物变性、净化钢液；
b.一次加热工艺，装钢时炉膛温度≤750℃，焖钢2～4小时以减少炉温与钢锭的温差，降低钢锭内外温差导致的应力，高温段目标保温温度1220～1240℃、保温时间16～18小时，总加热时间15min/cm；为了有效发挥Ni、Cr、Cu、Mo等元素的作用，需要有足够高的加热温度使Ni、Cr、Cu等合金元素及Mo等碳化物充分溶解，达到奥氏体单一组织，容易产生变形，但加热温度过高促使奥氏体晶粒长大；而通过合理控制温度上限，能避免加热温度过高促使奥氏体晶粒长大导致的后序晶粒只能在粗化的基础上细化。因此，结合钢锭的锭型特点，采用上述一次加热工艺；同时出钢前翻钢保证钢锭均匀透烧，确保表面氧化铁皮易去除；
c.开坯轧制工艺，采用“高温、低速、大压下”，开轧温度1050～1100℃，道次压下量60～70mm，促进内部疏松有效焊合、铸态组织充分破碎、钢板晶粒均匀细化，开坯至400mm厚，轧制结束钢板温度控制在950～980℃；
d.二次加热及轧制工艺，中间坯四切后装均热坑，高温段目标温度1220～1240℃、总保温时间5～6小时，二次成材轧制时无需再次展宽，直接展长至成品厚度，道次压下量≥30±5mm，确保变形渗透至厚度1/2处，促进晶粒进一步细化；开轧温度≥1020℃，终轧温 度≤950℃，轧制过程中使用高压水降温，待钢板表面充分返红后方可开始轧制，轧制总时间控制在3～4分钟，轧制完毕开启ACC入水冷却两遍快速将钢板表面及心部温度降至未再结晶区，入水温度900～950℃、返红温度800～830℃，快速冷却有利于缩小钢板厚度中心区域与表面温度差，抑制奥氏体晶粒长大及再结晶，促进晶粒细化及晶粒均匀性；
e.热处理工艺，采用高温淬火+临界淬火+回火热处理，其中第一次淬火加热温度920～940℃，加热时间2.4min/mm，热态钢板出炉后淬火机冷却至常温，水温15～18℃；第二次淬火加热温度860～870℃，加热时间2.4min/mm，热态钢板出炉后淬火机冷却至常温，水温15～18℃；淬火后装入淬火炉650±20℃回火，空冷至常温。
本公开提供的50～120mm厚高强水电HY950CF钢板具有较高的低温冲击韧性、可焊接性、耐腐蚀性能，需要说明的是，高强钢通过单相奥氏体淬火获得单一组织对于提升强度、改善韧性效果明显，热处理过程中既要完全奥氏体化保证淬透性，又要避免晶粒过分长大影响低温冲击韧性，第一次淬火提高淬火温度，保证碳化物及合金元素充分奥氏体化，为组织均匀化打好基础，第二次淬火为临界区淬火，保证完成奥氏体化的同时防止晶粒过分长大，最终通过高温回火充分消除应力，得到组织均匀细小的贝氏体回火组织，提高冲击韧性及整板强度均匀性。
公开采用一种全新的成分设计，通过合理控制淬透性元素加入量，并经过热处理后得到100％贝氏体回火组织；结合本公开稀土元素加入工艺，实现钢液净化、变质夹杂物，有效提升稀土钢的低温冲击韧性；采用一种全新的钢板成材工艺，增加钢锭厚度、提高轧制压缩比、以及改进钢锭加热轧制工艺，确保钢板内部质量达到锻件水平，实现以轧代锻；热处理环节通过高低搭配多次淬火，保证淬透性的同时细化奥氏体晶粒，并通过改进型回火提高整板力学性能的均匀性。
实施例
下面结合附图及实施例，对本公开的技术特征作进一步描述。
生产一种50～120mm厚高强水电HY950CF钢板，包含如下质量百分比的化学成分(单位，wt％)：C：0.09～0.12、Si：0.15～0.25、Mn：0.30～0.60、P≤0.010、S≤0.003、Als：0.020～0.040、Nb：0.02～0.03、V：0.04～0.1、Cr：1.2～1.6、Ni：2.4～2.8、Cu：0.8～1.0、Mo：0.2～0.3、Re：0.0015～0.0025，其它为Fe和残留元素。
其生产方法包括以下工艺流程：KR铁水预处理、转炉冶炼、吹氩处理、VD脱碳、LF精炼、VD精炼、浇铸工艺、钢锭清理和涂料、开坯加热和轧制、二次加热和轧制、热处理。如下：
1)KR铁水预处理工艺：到站铁水前渣必须扒干净，保证液面渣层厚度≤25mm，铁水经KR处理后硫含量控制在0.005％以下，脱硫温降≤25℃；
2)转炉冶炼：入炉铁水S≤0.005％、P≤0.050％，铁水温度≥1280℃，转炉加入废钢必须为干燥的优质边角料及含镍特种废钢，转炉装入量按浇钢铸余6～8吨控制，出钢温度≥1600℃、0.04％≤C≤0.07％、P≤0.007％，出钢结束采用挡渣锥挡渣，若挡渣失败，必须提前抬炉，确保转炉下渣厚度控制在20mm以下，以避免下渣回P；
3)吹氩处理：钢水到氩站后，禁止向钢水中加入合金、铝线或辅料，同时也禁止吹氩。钢水直接吊至VD炉真空处理，离站温度按照≥1560℃控制；
4)VD脱碳：确保钢水到VD温度≥1540℃，钢水坐落至VD炉后，根据出钢C含量高低适当加入碳粉，然后盖盖进行抽真空操作，钢水在VD炉抽真空阶段应调大氩气量充分实现真空脱碳目的，保压时间按照≥10min，离站温度≥1535℃；
5)LF精炼：按照大渣量工艺标准造渣，石灰加入量1000～1200公斤，碱度按4.5～6.5控制，一加热3min后，先加入50kg电石，再加入20～40kg铝粒，此后每隔2min向钢包中用铁锨添加2～4锨铝粒，以确保炉渣变白为准；二加热根据埋弧效果每次加入10～30kg的电石，同时每隔2min用铁锨向钢包中添加1～3锨铝粒，以确保整个二加热过程维持白渣；三加热脱氧剂的加入视炉渣颜色加入，维持白渣即可；精炼过程中要求白渣保持时间25～35分钟；
6)VD精炼：VD保压时间按照≥18min控制，要求在67Pa的真空度下，保压过程钢水翻腾效果良好，H含量要求≤1.0PPm；破空后及时添加稻壳软吹5～8min，然后准备吊包离站，离站温度控制在1578～1583℃左右；
7)浇铸工艺：保温帽上线温度大于160℃，使用45吨定厚调宽水冷钢锭模，钢锭本体厚度960～990mm、宽度2150mm、高度2730mm，摆模过程必须确保所有耐辅材干燥，并确保浇注系统干燥、清洁，所用水冷模必须保证锥度(30mm)同时侧边设置挤压机构，在凝固后期对铸锭宽边形成挤压，高效贴合冷却形成致密组织，钢锭帽口采取有效的保温措施，在凝固过程中使钢锭内部形成上大下小的补缩通道；浇注温度按照1555～1560℃进行控制；钢水到站后温度合适(在标准上限—上限+3℃)且镇静并测温确认符合浇注要求后开浇；若钢水到站温度不符合前述标准，则立即进行软吹氩，吹氩结束后要求镇静5min后开浇，浇注过程向中注管内加喂型号RECe‐48，喂丝速度15m/min。浇注结束后必须确保帽口保温效果。
8)钢锭清理和涂料：钢锭脱模后的24h内清理完毕，清理温度≥200℃，清理后堆垛在缓冷坑缓冷至50～100℃开始喷涂抗氧化涂料。
9)开坯加热和轧制：钢锭总加热时间15min/cm，装钢时炉膛温度≤750℃，焖钢2～4小时来减少炉温与钢锭之间温差，降低钢锭内外温差导致的应力差，高温段目标保温温度1220～1240℃、保温时间16～18小时；轧制过程采用“高温、低速、大压下”，开轧温度1050～ 1100℃，充分发挥3800mm轧机大轧制力优势，单道次压下量控制在60～70mm，确保形变渗透至厚度1/2处，实现钢锭内部疏松有效焊合、铸态组织充分破碎、促进钢板晶粒均匀细化，开坯规格400×2200×L mm，轧制厚度为400mm时放走，轧制结束温度950～980℃；
10)二次加热和轧制：中间坯四切后装均热坑，高温段目标温度1220～1240℃、总保温时间5～6小时，二次成材轧制时无需再次展宽，直接展长至成品厚度，道次压下量≥30±5mm，开轧温度≥1020℃，终轧温度≤950℃，轧制过程中使用高压水降温，待钢板表面充分返红后方可开始轧制，轧制总时间控制在3～4分钟，轧制完毕开启ACC入水冷却两遍快速将钢板表面及心部温度降至未再结晶区，入水温度900～950℃、返红温度800～830℃；
11)热处理：为有效提高强度、保证低温冲击韧性，采用两次淬火+回火热处理工艺，淬火炉第一次淬火加热温度920～940℃，加热时间＝钢板实厚×2.4min/mm，热态钢板出炉后淬火机冷却至常温，水温15～18℃；第二次淬火加热温度860～870℃，加热时间＝钢板实厚×2.4min/mm，热态钢板出炉后淬火机冷却至常温，水温15～18℃；淬火后装入淬火炉650±20℃回火，空冷至常温后取样检测，下表1为检测结果：
表1本公开的方法制备的钢板的检测结果
检测分析：钢板的化学成分、力学性能试件取样位置及试样制备按照标准GB/T 2975力学性能试验取样位置及试样的制备规定进行。低温冲击韧性试验按GB/T 229标准进行，拉伸性能试验按GB/T228标准进行，对钢板在供货状态各项力学性能及金相组织进行了全面检验。
从以上数据来看，钢板厚度1/4处、1/2处强度富余量适中且有良好的低温冲击韧性，各项性能指标均满足高强水电HY950CF用钢要求。
金相检测结果：(1)夹杂物A+B+D≤2.0级；(2)组织：贝氏体回火组织。
外检及探伤：所研制的钢板外检正品率100％，最终钢板探伤达到GB/T 2970《厚钢板超检验方法》的I级探伤要求。
以上所描述的仅为本公开的较佳实施方式，上述具体实施方式不是对本公开的限制凡本领域的普通技术人员根据以上描述所做的润饰、修改或等同替换，均属于本公开的保护范围。
工业实用性
本公开提供了一种高强度水电工程用HY950CF钢板及其制备方法。本公开的方法通过稀土元素的加入有利于钢液净化、变质夹杂物，钢的低温冲击韧性。本公开获得的钢板具有高强度、高韧性、抗疲劳、抗层状撕裂性能，以及良好的焊接性及耐腐蚀性能，能满足在大型高水头电站压力钢管长期服役使用要求，因此具备优异的实用性。

Claims (11)

  1. 一种高强度水电工程用HY950CF钢板，其特征在于：所述钢板的厚度为50～120mm，包含如下质量百分比的化学成分：
    C：0.09～0.12wt％、Si：0.15～0.25wt％、Mn：0.30～0.60wt％、P≤0.010wt％、S≤0.003wt％、Als：0.020～0.040wt％、Nb：0.02～0.03wt％、V：0.04～0.1wt％、Cr：1.2～1.6wt％、Ni：2.4～2.8wt％、Cu：0.8～1.0wt％、Mo：0.2～0.3wt％、Re：0.0015～0.0025wt％，其它为Fe和残留元素。
  2. 一种高强度水电工程用HY950CF钢板，其特征在于：所述钢板的厚度为50～120mm，包含如下质量百分比的化学成分：
    C：0.09～0.12wt％、Si：0.15～0.25wt％、Mn：0.30～0.60wt％、P≤0.010wt％、S≤0.003wt％、Als：0.020～0.040wt％、Nb：0.02～0.03wt％、V：0.04～0.1wt％、Cr：1.2～1.6wt％、Ni：2.4～2.8wt％、Cu：0.8～1.0wt％、Mo：0.2～0.3wt％、Re：0.0015～0.0025wt％，其它为Fe和残留元素，碳当量Ceq＜0.7，组织为贝氏体回火组织，‐60℃纵横向V型冲击功≥127J。
  3. 一种高强度水电工程用HY950CF钢板的生产方法，所述方法包括以下步骤：
    步骤1.将钢水经浇铸得到钢锭，其中，所述浇铸中加入Re丝；
    步骤2.对步骤1得到的钢锭进行一次加热，其中，高温段目标保温温度1220～1240℃，保温时间16～18小时；
    步骤3.对步骤2加热后的钢锭进行开坯轧制，得到钢板，其中，开轧温度1050～1100℃，道次压下量60～70mm，轧制结束钢板温度控制在950～980℃；
    步骤4.对步骤3得到的钢板进行二次加热，其中，高温段目标保温温度1220～1240℃、保温时间5～6小时；
    步骤5.对步骤4加热后的钢板进行二次轧制，其中，道次压下量≥30±5mm，开轧温度≥1020℃，终轧温度≤950℃，轧制完毕后，将钢板表面及心部温度降至未再结晶区；
    步骤6.将步骤5得到的钢板进行热处理，其中所述钢板依次进行高温淬火处理、临界淬火处理和回火处理；并且所述高温淬火加热温度920～940℃，所述临界淬火加热温度860～870℃，所述回火处理温度650±20℃；
    步骤7.将步骤6的钢板冷却至常温，即得。
  4. 根据权利要求3所述的方法，其中，在步骤1中，所述钢锭的本体厚度960～990mm，浇注温度按照1555～1560℃进行控制，浇注过程向中注管内加喂Re丝，喂丝速度10-20m/min。
  5. 根据权利要求3或4所述的方法，其中，在步骤1中，经过铁水预处理、转炉 冶炼、吹氩处理、VD脱碳、LF精炼和VD精炼，得到所述钢水。
  6. 根据权利要求3至5中任一项所述的方法，其中，在步骤2中，装钢以进行加热时，炉膛温度≤750℃，并在加热之前焖钢2～4小时；
    可选地，在步骤2中，总加热时间10-20min/cm。
  7. 根据权利要求3至6中任一项所述的方法，其中，在步骤4中，所述二次轧制还包含切坯操作；可选地，中间坯四切后装均热坑；
    可选地，在步骤5中，在二次轧制之前，使用高压水降温，待钢板表面充分返红后方开始轧制；
    可选地，二次轧制总时间3～4分钟；
    可选地，在步骤5中，所述二次成材轧制时无需再次展宽，直接展长至成品厚度；
    可选地，在步骤5中，二次轧制完毕后，开启ACC入水冷却两遍以将钢板表面及心部温度降至未再结晶区；
    可选地，所述钢板的入水温度900～950℃、所述钢板的返红温度800～830℃。
  8. 根据权利要求3至7中任一项所述的方法，其中，在步骤6中，所述高温淬火的加热温度920～940℃，加热时间2～3min/mm，淬火用水温度15～18℃；
    可选地，在步骤6中，所述临界淬火的加热温度860～870℃，加热时间2～3min/mm，淬火用水温度15～18℃；
    可选地，在步骤6中，所述回火处理为淬火炉650±20℃回火，空冷至常温。
  9. 根据权利要求1或2所述的高强度水电工程用HY950CF钢板生产方法，其特征在于，
    所述方法包括以下步骤：钢锭浇铸、一次加热、开坯轧制、二次加热及轧制、热处理，并包含，
    a.钢锭浇铸，钢锭本体厚度960～990mm，浇注温度按照1555～1560℃进行控制，浇注过程向中注管内加喂Re丝，喂丝速度10～20m/min；
    b.一次加热工艺，装钢时炉膛温度≤750℃，焖钢2～4小时，高温段目标保温温度1220～1240℃、保温时间16～18小时，总加热时间10～20min/cm；
    c.开坯轧制工艺，开轧温度1050～1100℃，道次压下量60～70mm，开坯至400mm厚，轧制结束钢板温度控制在950～980℃；
    d.二次加热及轧制工艺，中间坯四切后装均热坑，高温段目标温度1220～1240℃、总保温时间5～6小时，二次成材轧制时无需再次展宽，直接展长至成品厚度，道次压下量≥30±5mm，开轧温度≥1020℃，终轧温度≤950℃，轧制过程中使用高压水降温，待钢板表面充分返红后方可开始轧制，轧制总时间控制在3～4分钟，轧制完毕开启 ACC入水冷却两遍快速将钢板表面及心部温度降至未再结晶区，入水温度900～950℃、返红温度800～830℃；
    e.热处理工艺，采用高温淬火+临界淬火+回火热处理，其中高温淬火加热温度920～940℃，加热时间2.4min/mm，热态钢板出炉后淬火机冷却至常温，水温15～18℃；临界淬火加热温度860～870℃，加热时间2.4min/mm，热态钢板出炉后淬火机冷却至常温，水温15～18℃；淬火后装入淬火炉650±20℃回火，空冷至常温，即得。
  10. 根据权利要求1或2所述的高强度水电工程用HY950CF钢板生产方法，其特征在于，
    所述方法包括以下步骤：钢锭浇铸、一次加热、开坯轧制、二次加热及轧制、热处理，并包含，
    a.钢锭浇铸，钢锭本体厚度960～990mm，浇注温度按照1555～1560℃进行控制，浇注过程向中注管内加喂Re丝改善内部质量，喂丝速度15m/min；
    b.一次加热工艺，装钢时炉膛温度≤750℃，焖钢2～4小时以减少炉温与钢锭的温差，降低钢锭内外温差导致的应力，高温段目标保温温度1220～1240℃、保温时间16～18小时，总加热时间15min/cm；
    c.开坯轧制工艺，采用“高温、低速、大压下”，开轧温度1050～1100℃，道次压下量60～70mm，开坯至400mm厚，轧制结束钢板温度控制在950～980℃；
    d.二次加热及轧制工艺，中间坯四切后装均热坑，高温段目标温度1220～1240℃、总保温时间5～6小时，二次成材轧制时无需再次展宽，直接展长至成品厚度，道次压下量≥30±5mm，开轧温度≥1020℃，终轧温度≤950℃，轧制过程中使用高压水降温，待钢板表面充分返红后方可开始轧制，轧制总时间控制在3～4分钟，轧制完毕开启ACC入水冷却两遍快速将钢板表面及心部温度降至未再结晶区，入水温度900～950℃、返红温度800～830℃；
    e.热处理工艺，采用高温淬火+临界淬火+回火热处理，其中第一次淬火加热温度920～940℃，加热时间2.4min/mm，热态钢板出炉后淬火机冷却至常温，水温15～18℃；第二次淬火加热温度860～870℃，加热时间2.4min/mm，热态钢板出炉后淬火机冷却至常温，水温15～18℃；淬火后装入淬火炉650±20℃回火，空冷至常温。
  11. 根据权利要求3-8中任一项所述的方法制备的钢板；
    可选地，所述钢板为高强度水电工程用HY950CF钢板，所述钢板的厚度为50～120mm，包含如下质量百分比的化学成分：
    C：0.09～0.12wt％、Si：0.15～0.25wt％、Mn：0.30～0.60wt％、P≤0.010wt％、S≤0.003wt％、Als：0.020～0.040wt％、Nb：0.02～0.03wt％、V：0.04～0.1wt％、 Cr：1.2～1.6wt％、Ni：2.4～2.8wt％、Cu：0.8～1.0wt％、Mo：0.2～0.3wt％、Re：0.0015～0.0025wt％，其它为Fe和残留元素；
    可选地，所述钢板碳当量Ceq＜0.7，组织为贝氏体回火组织，‐60℃纵横向V型冲击功≥127J。
PCT/CN2023/124770 2022-11-26 2023-10-16 一种高强度水电工程用hy950cf钢板及其生产方法 WO2024109390A1 (zh)

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