WO2023213109A1 - Accurate heat treatment method for low-carbon low-alloy high-strength thin steel plate - Google Patents

Accurate heat treatment method for low-carbon low-alloy high-strength thin steel plate Download PDF

Info

Publication number
WO2023213109A1
WO2023213109A1 PCT/CN2023/075923 CN2023075923W WO2023213109A1 WO 2023213109 A1 WO2023213109 A1 WO 2023213109A1 CN 2023075923 W CN2023075923 W CN 2023075923W WO 2023213109 A1 WO2023213109 A1 WO 2023213109A1
Authority
WO
WIPO (PCT)
Prior art keywords
steel plate
temperature
low
heat treatment
transformation
Prior art date
Application number
PCT/CN2023/075923
Other languages
French (fr)
Chinese (zh)
Inventor
李贤君
张文良
罗平
姜超
王德成
孙立壮
贾巍
Original Assignee
中国机械总院集团北京机电研究所有限公司
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by 中国机械总院集团北京机电研究所有限公司 filed Critical 中国机械总院集团北京机电研究所有限公司
Priority to ZA2023/06225A priority Critical patent/ZA202306225B/en
Publication of WO2023213109A1 publication Critical patent/WO2023213109A1/en

Links

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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • 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
    • C21D1/185—Hardening; Quenching with or without subsequent tempering from an intercritical temperature
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D11/00—Process control or regulation for heat treatments
    • C21D11/005—Process control or regulation for heat treatments for cooling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/001—Austenite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/008—Martensite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/009—Pearlite
    • 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
    • C21D2241/00—Treatments in a special environment
    • C21D2241/01—Treatments in a special environment under pressure
    • 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

Definitions

  • the invention relates to the field of material processing technology, and in particular to a precise heat treatment method for low carbon, low alloy, high strength thin steel plates.
  • Low-carbon, low-alloy, high-strength thin steel plates are widely used in key fields such as national defense and military industry, engineering machinery, mining and metallurgical engineering, and rail transportation. As these key areas develop toward heavy-duty, high-speed and long-life, the low-carbon, low-alloy, high-strength thin steel plates they require also need to move toward "larger scale, more complex structures, more integrated forms, lighter materials, and more precise quality.” direction development. More stringent requirements have been put forward for the various performance indicators of steel plates: they must not only meet conventional properties such as high strength and easy welding, but also have apparent properties such as excellent plate shape, low residual stress, and excellent surface quality.
  • low-carbon, low-alloy, high-strength thin steel plates In order to obtain the required properties of low-carbon, low-alloy, high-strength thin steel plates, they must be heat treated. Furthermore, the thin steel plate needs to be rapidly quenched and cooled during the quenching stage of the final heat treatment process to obtain a full martensite structure, thereby ensuring that the thin steel plate obtains the required strength and toughness. Since low-carbon, low-alloy high-strength thin steel plates have the characteristics of extremely large length (width)-to-thickness ratio and weak stiffness, large quenching distortion is easily produced during the rapid quenching stage of the heat treatment process.
  • thin steel plates are prone to serious deformations such as turtleback, bulges, and warping, which usually require post-processing corrections.
  • low-carbon, low-alloy, high-strength thin steel plates have high strength after heat treatment, and need to be processed after heat treatment.
  • the low-carbon and low-alloy thin steel plate must be corrected, ground and calibrated multiple times before the required plate shape can be obtained.
  • the steel plate will generate large residual stress, which will reduce the various properties of the thin plate, especially the fatigue performance, thus greatly shortening the service life of the thin steel plate.
  • constant clamping quenching thin steel plates are prone to defects such as local indentations, plastic deformation, and micro-cracks, which affect the apparent quality of the thin steel plates and even lead to direct scrapping of the thin steel plates.
  • One of the purposes of the present invention is to provide a precise heat treatment method for low-carbon, low-alloy, high-strength thin steel plates, so as to solve at least one of the technical problems existing in the prior art.
  • the second object of the present invention lies in the low-carbon, low-alloy, high-strength thin steel plate prepared by the above method.
  • a precise heat treatment method for low-carbon, low-alloy, high-strength thin steel plates including the following steps:
  • Step (a) annealing treatment to transform the structure of the steel plate into ferrite and pearlite structures
  • Step (c) clamping quenching treatment to transform the austenite structure in step (b) into a martensite structure, wherein the clamping force of the steel plate changes;
  • Step (d) is a tempering treatment to transform the martensite structure in step (c) into a tempered martensite structure.
  • step (c) the application of the clamping force is divided into the following stages (1)-(3):
  • the clamping force is the maximum value of the deformation force in the austenite stage
  • the clamping force is the maximum value of the deformation force in the austenite transformation to martensite stage
  • the clamping force is the maximum value of the deformation force in the martensite stage
  • the deformation force is determined by the evolution of the deformation force of the steel plate during quenching.
  • step (c) includes: quenching the clamped steel plate at a water spray flow rate and water spray pressure corresponding to a minimum cooling rate greater than the martensite structure, and cooling to a temperature lower than that of the martensite structure.
  • the temperature T4 is at least 50-80°C lower than the martensite end transformation temperature.
  • the annealing operation in step (a) includes: heating the steel plate to a temperature T1 higher than the austenite end transformation temperature for a holding time t1, and then cooling to a temperature lower than the bainite start transformation temperature. T2.
  • the temperature T1 is 80-100°C higher than the austenite end transformation temperature, and the time t1 is 1.5-5 times the millimeter thickness of the steel plate;
  • the temperature T2 is at least 80-100°C lower than the starting temperature of bainite transformation.
  • the austenizing treatment in step (b) includes heating the steel plate to a temperature T3 higher than the austenite end transformation temperature and a holding time t2.
  • the temperature T3 is 30-80°C higher than the austenite end transformation temperature, and the time t2 is 1.5-2 times the millimeter thickness of the steel plate.
  • the tempering treatment operation in step (d) includes: heating the steel plate to 180-680°C for a holding time t3, where the time t3 is 10-30 times the millimeter thickness of the steel plate.
  • step (a) the step of detecting the isothermal transformation curve and the continuous cooling transformation curve of the steel plate is also included.
  • the heat treatment method provided by the present invention can solve the problems of deformation, indentation, large residual stress, etc. that are prone to occur during the heat treatment of high-strength thin steel plates in the prior art, and achieve precise coordinated controllable shape control.
  • the obtained steel plate has small deformation and no obvious surface.
  • the indentation also has good mechanical properties, reduces production costs and simplifies process steps.
  • Figure 1 is a schematic dimensional view of a low-carbon, low-alloy, high-strength thin steel plate provided by an embodiment of the present invention
  • Figure 2 is a picture of the quenching deformation of the steel plate under free quenching conditions in Comparative Example 1 of the present invention
  • Figure 3 is a photo of defects such as indentation of the steel plate under constant clamping and quenching conditions in Comparative Example 2 of the present invention
  • Figure 4 is a continuous cooling transformation curve of a low-carbon low-alloy thin steel plate material in an embodiment of the present invention, where Ac1: the starting temperature of austenite transformation, Ac3: the ending temperature of austenite transformation, Ms: the starting temperature of martensite transformation, Mf : Martensite end transformation temperature;
  • Figure 5 is the isothermal transformation curve of the low-carbon low-alloy thin steel plate material in the embodiment of the present invention, where Ac1: the starting temperature of austenite transformation, Ac3: the ending temperature of austenite transformation, Ms: the starting temperature of martensite transformation, Mf: Martensite end transformation temperature;
  • Figure 6 is a graph showing the temperature change curve of the steel plate core with time under different quenching flow conditions in the embodiment of the present invention.
  • Figure 7 is a curve of the deformation force of the steel plate changing with time in the embodiment of the present invention.
  • Figure 8 is a variation curve of the clamping force over time of the variable clamping force quenched steel plate in the embodiment of the present invention.
  • Figure 9 is a steel plate obtained after precise heat treatment in an embodiment of the present invention.
  • the precise heat treatment method of low-carbon, low-alloy, high-strength thin steel plates includes the following steps:
  • Step (a) annealing treatment transforms the structure of the steel plate into ferrite and pearlite structures.
  • the structure of the steel plate after annealing becomes uniform ferrite and beads.
  • the light body structure improves the composition and structural uniformity of the steel plate, thereby improving the uniformity of the structural transformation in step (c), reducing structural stress and reducing deformation of the steel plate.
  • Step (b) austenization treatment transforms the ferrite and pearlite structures in step (a) into austenite structures.
  • step (c) the structure of the steel plate after the austenization treatment is transformed from the ferrite and pearlite after the annealing treatment to the austenite structure, preparing the structure for the clamping quenching treatment in step (c).
  • Step (c) is a clamping quenching treatment to transform the austenite structure in step (b) into a martensite structure, wherein the clamping force of the steel plate changes.
  • the structure of the steel plate is completely transformed from austenite during austenization treatment to martensite structure.
  • the adjustable clamping force of the steel plate makes the steel plate both restricted in deformation and free to expand and contract during the clamping and quenching treatment.
  • variable pressure clamping scheme can not only limit the deformation of the steel plate using the conventional free quenching cooling method, but also avoid surface defects such as indentations and scratches caused by the conventional constant clamping force quenching cooling method.
  • Analysis of the quenching process of the steel plate shows that the clamping quenching process of the steel plate is mainly divided into the following three stages:
  • Preliminary shaping stage At this stage, the steel plate is processed in the austenite supercooled zone, which has low strength and good plasticity, and only generates thermal stress. In addition, due to the cooling shrinkage of the steel plate at this stage, the steel plate shrinks from the periphery of the steel plate to the center of the steel plate, so at this stage It can apply a continuous small clamping force (the specific clamping force varies depending on the steel plate being processed) to limit deformation and avoid indentation defects on the surface of the steel plate. At the same time, the steel plate can shrink toward the center to avoid scratches caused by excessive clamping force. and surface tensile stress and other defects.
  • a continuous small clamping force the specific clamping force varies depending on the steel plate being processed
  • Cooling shape control stage At this stage, the structure of the steel plate changes from austenite to martensite, the strength of the steel plate increases, and structural stress and thermal stress are generated at the same time.
  • the stress is relatively large, which is a critical stage for shape control of the steel plate, and at this stage
  • the cooling of the steel plate causes the steel plate to shrink from the periphery of the steel plate to the center of the steel plate, and the volume expansion of the steel plate changes from austenite to martensite, causing the steel plate to expand from the center of the steel plate to the periphery of the steel plate.
  • the two can partially offset each other, so a greater force can be applied at this stage.
  • the large clamping force (the specific clamping force varies depending on the steel plate being processed) prevents the steel plate from deforming.
  • Step (d) is a tempering treatment to transform the martensite structure in step (c) into a tempered martensite structure.
  • the steel plate changes from martensite structure to tempered martensite or tempered sorbite, so that the steel plate can obtain better comprehensive performance matching of strength and toughness.
  • the clamping force can be applied in the following manner:
  • the clamping force is the maximum value of the deformation force in the austenite stage
  • the clamping force is the maximum value of the deformation force in the austenite transformation to martensite stage
  • the clamping force in stage (3) is the maximum value of the deformation force in the martensite stage.
  • the change of clamping force is a six-stage clamping, which are the clamping force changing to stage (1), the clamping force maintenance of stage (1), and the clamping force changing from stage (1) to stage (2).
  • step (i) Obtain the isothermal transformation curve and continuous cooling transformation curve of the steel plate, thereby obtaining the minimum cooling rate, austenite end transformation temperature, bainite start transformation temperature, martensite start transformation temperature, martensitic structure Key phase transformation temperatures such as the end-transformation temperature of titanium are used to guide the optimization of the precise shape control of high-strength thin steel plates based on physical and chemical experiments and data simulation processes.
  • the heating temperature and cooling temperature of the annealing treatment in step (a), and the step (b) are in Austria
  • (ii) Use numerical simulation methods to obtain optimized quenching process parameters for the steel plate.
  • the process parameters should convert the steel plate into a fully martensitic structure, that is, the minimum cooling rate to obtain the steel plate is greater than the minimum cooling rate corresponding to the above-mentioned minimum cooling rate to obtain a fully martensitic structure. of water jet flow and Water spray pressure and other parameters.
  • the operation of the clamping quenching treatment in step (c) includes: quenching the clamped steel plate at a water spray flow rate and water spray pressure greater than the minimum cooling rate of the martensitic structure, and cooling to a temperature lower than the martensitic structure.
  • Temperature T4 which is the end temperature of stenite transformation.
  • the temperature T4 is preferably at least 50-80°C lower than the martensite end transformation temperature.
  • the temperature T4 can be, but is not limited to, at least 50°C, 55°C, 60°C, 65°C, 70°C, 75°C lower than the martensite end transformation temperature. °C or 80°C.
  • the annealing operation in step (a) includes: heating the steel plate to a temperature T1 higher than the austenite end transformation temperature for a holding time t1, and then cooling to a temperature lower than the bainite start transformation temperature. T2.
  • the temperature T1 is preferably 80-100°C higher than the austenite end transformation temperature, such as 80°C, 85°C, 90°C, 95°C or 100°C, etc.; the time t1 is preferably 1.5-5 times the millimeter thickness of the steel plate, as needed It should be noted that time t1 is measured in minutes.
  • time t1 is 15-50 minutes; temperature T2 is preferably at least 80-100°C lower than the bainite starting transformation temperature, such as 80°C or 85°C. , 90°C, 95°C or 100°C, etc.
  • the austenizing treatment operation in step (b) includes: heating the steel plate to a temperature T3 higher than the austenite end transformation temperature and a holding time t2.
  • Temperature T3 is preferably 30-80°C higher than the austenite end transformation temperature, such as 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C
  • time t2 is preferably 1.5-2 times the millimeter thickness of the steel plate.
  • the tempering treatment operation in step (d) includes: heating the steel plate to 180-680°C for a holding time t3, where the time t3 is 10-30 times the millimeter thickness of the steel plate.
  • the heating temperature of the steel plate may be, but is not limited to, 180°C, 280°C, 380°C, 480°C, 580°C or 680°C.
  • the precise heat treatment method of low-carbon, low-alloy, high-strength thin steel plates is as follows:
  • the first stage is based on physical and chemical tests and data simulation process optimization:
  • Step 1 Obtain the isothermal transformation curve and continuous cooling transformation curve of the corresponding material of the low-carbon, low-alloy high-strength thin steel plate; guide step (a) in optimizing the precise controllability and shape control of the high-strength thin steel plate (second phase) based on physical and chemical tests and data simulation processes The heating temperature of the annealing treatment and the cooling temperature of the furnace, the heating temperature of the Austrian treatment in step (b), and the water cooling temperature in step (c).
  • Step 2 Use numerical simulation methods to obtain optimized quenching process parameters for low-carbon and low-alloy thin steel plates; this can guide the spraying in step (c) of step (c) of high-strength thin steel plates based on physical and chemical tests and data simulation processes to optimize the precise shape and shape control of high-strength thin steel plates (the second phase). Design of shower system parameters.
  • Step 3 Use numerical simulation methods to determine the evolution of the deformation force of the steel plate during the above quenching process
  • Step 4 On the basis of Step 3, combined with the steel plate quenching cooling theory and the principle of action and reaction force, obtain the optimal value of the clamping force of low-carbon, low-alloy, high-strength thin plates. It can guide the optimization design of the clamping force in step (c) of the high-strength thin steel plate in step (c) based on physical and chemical tests and data simulation processes.
  • the high-strength thin steel plate is clamped and quenched with variable pressure:
  • Step (a) annealing treatment, the steel plate is heated to a certain temperature T1 and kept for a period of time t1, and then cooled in the furnace to a certain temperature T2 and cooled out of the furnace;
  • Step (b) Austrian treatment, heating the steel plate to a certain temperature T3 and holding it for a period of time t2;
  • Step (c) clamping quenching treatment, quickly transfer the steel plate to the quenching equipment, the quenching equipment clamps the steel plate, starts the spray system to water-cool the steel plate to a certain temperature T4;
  • the quenching intensity is optimized based on physical and chemical experiments and numerical simulation processes
  • Step 2 of (the first stage) is determined so that the steel plate can be completely transformed into martensite during the clamping quenching process in step (c) and avoid large quenching distortion caused by large stress caused by excessive cooling rate;
  • the clamping force exerted by the quenching equipment on the steel plate is determined and optimized according to steps 3 and 4 of the process optimization (first phase) based on physical and chemical experiments and numerical simulations, and the optimized variable pressure clamping method is designed, so that the steel plate is in step (c) During the clamping and quenching process, the deformation is restricted but can be freely expanded and contracted.
  • Step (d) tempering treatment, heating the steel plate to a certain temperature and keeping it warm for a period of time
  • the interval t3 enables the steel plate to obtain better comprehensive performance matching of strength and toughness.
  • the quenching process parameters in the clamping quenching process can regulate the structure/properties of the steel plate, so that the low-carbon low-alloy thin steel plate is quenched into high-strength martensite as a whole. Changing the clamping force can prevent the steel plate from causing large heat treatment deformation and surface indentations, scratches and other problems during the quenching process.
  • the invention also provides a low-carbon, low-alloy, high-strength thin steel plate prepared by the above method, which has excellent performance and appearance.
  • the dimensions of the low carbon low alloy thin steel plate are shown in Figure 1.
  • the steel plate is 12000mm long, 2000mm wide and 10mm thick.
  • the chemical composition of the steel plate is shown in Table 1.
  • Process optimization (first phase) based on physical and chemical experiments and numerical simulations includes the following steps:
  • Step 1 Obtain the continuous cooling transformation curve ( Figure 4) and isothermal transformation curve (Figure 5) of the low-carbon, low-alloy high-strength steel plate material through physical and chemical experiments; it can be obtained that the austenite end transformation temperature of the steel plate material is 820°C.
  • the starting temperature of martensite transformation is 500°C
  • the starting temperature of martensite transformation is 340°C
  • the ending temperature of martensite transformation is 200°C
  • the minimum cooling rate VLin to obtain a full martensite structure is 40°C/s.
  • Step 2 Use numerical simulation methods to obtain optimized quenching process parameters for low carbon and low alloy thin steel plates; design three quenching process plans - quenching process plan 1: quenching flow rate is 5L/m 2 *s, quenching pressure is 0.2MPa; Quenching process plan two: quenching flow rate is 10L/m 2 *s, quenching pressure is 0.2MPa; quenching process plan three: quenching flow rate is 15L/m 2 *s, quenching pressure is 0.2MPa.
  • the temperature variation curve of the steel plate core with time under different quenching process schemes is shown in Figure 6.
  • the cooling rate at the center of the steel plate is about 25°C/s, which is less than the minimum value required to obtain a full martensitic structure in the continuous cooling transformation curve in step 1.
  • the cooling rate V is 40°C/s, so the steel plate cannot obtain the required martensite structure under this quenching process condition; when the quenching process plan is 10L/m 2 *s, the cooling rate at the center of the steel plate is about 45°C /s, slightly larger than the minimum cooling rate VLin in the continuous cooling transformation curve in step 1 to obtain a full martensite structure is 40°C/s, so the steel plate can obtain the required martensite structure under this process condition ; When the quenching process plan is 20L/m 2 *s, the cooling rate at the center of the steel plate is about 98°C/s, which is greater than the minimum cooling rate V Pro in the continuous cooling transformation curve in step 1 to obtain a full martensitic structure.
  • the temperature is 40°C/s. Under this process condition, the steel plate can obtain the required martensite structure. Based on actual production, in order to save quenching water and facilitate the operation of the quenching process, the quenching process option 2 is selected.
  • the quenching flow rate is 10L/m 2 *s and the quenching pressure is 0.2MPa.
  • Step 3 Use numerical simulation methods to determine the evolution of the deformation force of the steel plate during the above quenching process, as shown in Figure 7.
  • the maximum deformation force during quenching is 158KN, and the deformation force changes continuously.
  • Step 4 On the basis of step 3, combined with the steel plate quenching cooling theory and the principle of action and reaction force, the optimal value of the clamping force of low-carbon low-alloy high-strength thin plate is obtained, as shown in Figure 8 (for austenite, austenite Body transformation martensite, martensite, the maximum deformation force in the three states), the clamping force increases to 70KN from 0s to 1s, the clamping force remains at 70KN from 1s to 5s, and the clamping force remains at 70KN from 5s to 5s.
  • Figure 8 for austenite, austenite Body transformation martensite, martensite, the maximum deformation force in the three states
  • the clamping force increases from 70KN to 158KN in 10s, the clamping force remains at 158KN between 10s and 16s, the clamping force decreases from 158KN to 90KN from 16s to 20s, and the clamping force remains at 90KN from 20s to 30s.
  • variable pressure clamping quenching treatment (second stage) of high-strength thin steel plates includes the following steps:
  • Step (a) annealing treatment, the steel plate is heated to 900°C and kept for 30 minutes, and then cooled to 400°C and cooled out of the furnace;
  • Step (b) Austrian treatment, heat the steel plate to a certain temperature of 860°C and keep it for 18 minutes;
  • Step (c) clamp and quench the steel plate, quickly transfer the steel plate to the quenching equipment,
  • the quenching equipment clamps the steel plate.
  • the clamping force is set as follows: the clamping force increases to 70KN from 0s to 1s, the clamping force remains at 70KN from 1s to 5s, and the clamping force increases from 70KN from 5s to 10s.
  • the clamping force remains at 158KN from 10s to 16s, the clamping force decreases from 158KN to 90KN from 16s to 20s, and the clamping force remains at 90KN from 20s to 30s; start the spray system (quenching flow is 10L /m 2 *s, quenching pressure is 0.2MPa) water-cool the steel plate for 30s, and cool the steel plate to 30°C;
  • Step (d) tempering treatment, heat the steel plate to 200°C and keep it warm for 200 minutes.
  • the steel plate obtained After testing, using the technology of the above embodiment, the steel plate obtained has small deformation, up to 10mm, and no obvious defects such as indentation on the surface. As shown in Figure 9, the yield strength is about 1500MPa, the tensile strength is about 1750MPa, and the elongation is 15% to 17%, achieving precise heat treatment of low-carbon, low-alloy, high-strength thin steel plates.
  • step (c) the steel plate is free quenched.
  • the quenching flow rate is Free quenching is performed under the quenching process conditions of 10L/m 2 *s and quenching pressure of 0.2MPa.
  • the deformation diagram of the steel plate under free quenching conditions is shown in Figure 2. It can be seen that under this quenching process, the steel plate is significantly deformed and cannot meet the usage requirements.
  • step c the steel plate is constantly clamped and quenched, and the quenching flow rate is 10L/m Constant clamping quenching is performed under the quenching process conditions of 2 *s, quenching pressure is 0.2MPa, and constant clamping force during quenching is 158000N.
  • the steel plate obtained under constant clamping quenching conditions is shown in Figure 3. It can be seen that under this quenching process condition, obvious defects such as indentations are produced on the surface of the steel plate, which affects the appearance quality and does not meet the usage requirements.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
  • Heat Treatment Of Sheet Steel (AREA)

Abstract

The present invention relates to the technical field of material processing, and provides an accurate heat treatment method for a low-carbon low-alloy high-strength thin steel plate. According to the accurate heat treatment method, the structure of a steel plate is sequentially converted into a ferrite and pearlite structure, an austenite structure, a martensite structure and a tempered martensite structure by means of annealing treatment, austenitizing treatment, clamping quenching treatment and tempering treatment in sequence, wherein the clamping force of the steel plate is variable in the clamping quenching treatment. The method achieves precise synergistic performance control and shape control; the obtained steel plate has small deformation, no obvious surface indentation and good mechanical properties; moreover, the production cost is reduced, and the process steps are simplified.

Description

低碳低合金高强薄钢板的精确热处理方法Precise heat treatment method for low-carbon, low-alloy high-strength thin steel plates 技术领域Technical field
本发明涉及材料加工技术领域，尤其是涉及一种低碳低合金高强薄钢板的精确热处理方法。The invention relates to the field of material processing technology, and in particular to a precise heat treatment method for low carbon, low alloy, high strength thin steel plates.
背景技术Background technique
低碳低合金高强薄钢板广泛应用于国防军工、工程机械、矿冶工程、轨道交通等重点领域。随着这些重点领域向重载高速长寿命方向发展，其所需的低碳低合金高强薄钢板也需要向“尺度大型化、结构复杂化、形式整体化、材料轻质化、质量精确化”方向发展。对钢板各性能指标提出了更苛刻要求：既需满足高强度、易焊接等常规性能，同时需兼备优异板形、低残余应力、优良表面质量等表观性能。Low-carbon, low-alloy, high-strength thin steel plates are widely used in key fields such as national defense and military industry, engineering machinery, mining and metallurgical engineering, and rail transportation. As these key areas develop toward heavy-duty, high-speed and long-life, the low-carbon, low-alloy, high-strength thin steel plates they require also need to move toward "larger scale, more complex structures, more integrated forms, lighter materials, and more precise quality." direction development. More stringent requirements have been put forward for the various performance indicators of steel plates: they must not only meet conventional properties such as high strength and easy welding, but also have apparent properties such as excellent plate shape, low residual stress, and excellent surface quality.
为使低碳低合金高强薄钢板获得所需性能，必须对其进行热处理。进一步的，薄钢板在最终热处理过程的淬火阶段需对其快速淬火冷却，获得全马氏体组织，从而确保薄钢板获得所需强度与韧性。由于低碳低合金高强薄钢板具有长(宽)厚比极大、弱刚度等特点，在热处理过程的快速淬火阶段极易产生大的淬火畸变。采用常规穿水式自由淬火，薄钢板易产生龟背、凸起、翘曲等严重变形，通常需要后处理进行修正，而低碳低合金高强薄钢板经热处理后强度高，需对热处理后的低碳低合金薄钢板多次矫正、修磨、火校后方可获得所需板形。然而经多次矫正、修磨后，钢板产生较大残余应力，会降低薄板的各项性能，尤其是疲劳性能，从而大大缩短薄钢板的服役寿命。采用恒定夹持淬火，薄钢板又容易产生局部压痕、塑性变形、微裂纹等缺陷，影响薄钢板表观质量甚至导致薄钢板直接报废。In order to obtain the required properties of low-carbon, low-alloy, high-strength thin steel plates, they must be heat treated. Furthermore, the thin steel plate needs to be rapidly quenched and cooled during the quenching stage of the final heat treatment process to obtain a full martensite structure, thereby ensuring that the thin steel plate obtains the required strength and toughness. Since low-carbon, low-alloy high-strength thin steel plates have the characteristics of extremely large length (width)-to-thickness ratio and weak stiffness, large quenching distortion is easily produced during the rapid quenching stage of the heat treatment process. Using conventional water-penetrating free quenching, thin steel plates are prone to serious deformations such as turtleback, bulges, and warping, which usually require post-processing corrections. However, low-carbon, low-alloy, high-strength thin steel plates have high strength after heat treatment, and need to be processed after heat treatment. The low-carbon and low-alloy thin steel plate must be corrected, ground and calibrated multiple times before the required plate shape can be obtained. However, after repeated correction and grinding, the steel plate will generate large residual stress, which will reduce the various properties of the thin plate, especially the fatigue performance, thus greatly shortening the service life of the thin steel plate. Using constant clamping quenching, thin steel plates are prone to defects such as local indentations, plastic deformation, and micro-cracks, which affect the apparent quality of the thin steel plates and even lead to direct scrapping of the thin steel plates.
有鉴于此，特提出本发明。 In view of this, the present invention is proposed.
发明内容Contents of the invention
本发明的目的之一在于提供一种低碳低合金高强薄钢板的精确热处理方法，以至少解决现有技术中存在的技术问题之一。One of the purposes of the present invention is to provide a precise heat treatment method for low-carbon, low-alloy, high-strength thin steel plates, so as to solve at least one of the technical problems existing in the prior art.
本发明的目的之二在于上述方法制备得到的低碳低合金高强薄钢板。The second object of the present invention lies in the low-carbon, low-alloy, high-strength thin steel plate prepared by the above method.
为了实现本发明的上述目的，特采用以下技术方案：In order to achieve the above objects of the present invention, the following technical solutions are adopted:
一种低碳低合金高强薄钢板的精确热处理方法，包括如下步骤：A precise heat treatment method for low-carbon, low-alloy, high-strength thin steel plates, including the following steps:
步骤(a)退火处理，将所述钢板的组织转变为铁素体和珠光体组织；Step (a) annealing treatment to transform the structure of the steel plate into ferrite and pearlite structures;
步骤(b)奥化处理，将步骤(a)中的铁素体和珠光体组织转变为奥氏体组织；Step (b) austenization treatment, transforming the ferrite and pearlite structures in step (a) into austenite structures;
步骤(c)夹持淬火处理，将步骤(b)中的奥氏体组织转变为马氏体组织，其中，所述钢板的夹持力是变化的；Step (c) clamping quenching treatment to transform the austenite structure in step (b) into a martensite structure, wherein the clamping force of the steel plate changes;
步骤(d)回火处理，将步骤(c)中的马氏体组织转变为回火马氏体组织。Step (d) is a tempering treatment to transform the martensite structure in step (c) into a tempered martensite structure.
进一步地，所述步骤(c)夹持淬火处理中，所述夹持力的施用分为如下阶段(1)-(3)：Further, in the clamping and quenching process of step (c), the application of the clamping force is divided into the following stages (1)-(3):
阶段(1)夹持力为奥氏体组织阶段变形力的最大值；Stage (1) The clamping force is the maximum value of the deformation force in the austenite stage;
阶段(2)夹持力为奥氏体转变马氏体阶段变形力的最大值；In stage (2), the clamping force is the maximum value of the deformation force in the austenite transformation to martensite stage;
阶段(3)夹持力为马氏体组织阶段变形力的最大值；In stage (3), the clamping force is the maximum value of the deformation force in the martensite stage;
优选地，所述变形力由所述钢板在淬火过程中变形力演变历程确定。Preferably, the deformation force is determined by the evolution of the deformation force of the steel plate during quenching.
进一步地，所述步骤(c)中夹持淬火处理的操作包括：夹持的钢板以大于马氏体组织最小冷却速度对应的喷水流量和喷水压力进行淬火，冷却至低于马氏体结束转变温度的温度T4；Further, the operation of clamping and quenching treatment in step (c) includes: quenching the clamped steel plate at a water spray flow rate and water spray pressure corresponding to a minimum cooling rate greater than the martensite structure, and cooling to a temperature lower than that of the martensite structure. The temperature T4 of the end transition temperature;
优选地，所述温度T4至少低于马氏体结束转变温度50-80℃。 Preferably, the temperature T4 is at least 50-80°C lower than the martensite end transformation temperature.
进一步地，所述步骤(a)中退火处理的操作包括：将所述钢板加热到高于奥氏体结束转变温度的温度T1保温时间t1，随后冷却至低于贝氏体开始转变温度的温度T2。Further, the annealing operation in step (a) includes: heating the steel plate to a temperature T1 higher than the austenite end transformation temperature for a holding time t1, and then cooling to a temperature lower than the bainite start transformation temperature. T2.
进一步地，所述温度T1高于奥氏体结束转变温度80-100℃，所述时间t1为所述钢板的毫米制厚度的1.5-5倍；Further, the temperature T1 is 80-100°C higher than the austenite end transformation temperature, and the time t1 is 1.5-5 times the millimeter thickness of the steel plate;
优选地，所述温度T2至少低于贝氏体开始转变温度80-100℃。Preferably, the temperature T2 is at least 80-100°C lower than the starting temperature of bainite transformation.
进一步地，所述步骤(b)中奥化处理的操作包括：将所述钢板加热到高于奥氏体结束转变温度的温度T3保温时间t2。Further, the austenizing treatment in step (b) includes heating the steel plate to a temperature T3 higher than the austenite end transformation temperature and a holding time t2.
进一步地，所述温度T3高于奥氏体结束转变温度30-80℃，所述时间t2为所述钢板的毫米制厚度的1.5-2倍。Further, the temperature T3 is 30-80°C higher than the austenite end transformation temperature, and the time t2 is 1.5-2 times the millimeter thickness of the steel plate.
进一步地，所述步骤(d)中回火处理的操作包括：将所述钢板加热到180-680℃，保温时间t3，所述时间t3为所述钢板的毫米制厚度的10-30倍。Further, the tempering treatment operation in step (d) includes: heating the steel plate to 180-680°C for a holding time t3, where the time t3 is 10-30 times the millimeter thickness of the steel plate.
进一步地，在所述步骤(a)之前还包括检测所述钢板的等温转变曲线和连续冷却转变曲线的步骤。Further, before step (a), the step of detecting the isothermal transformation curve and the continuous cooling transformation curve of the steel plate is also included.
上述精确热处理方法制备得到的低碳低合金高强薄钢板。Low-carbon, low-alloy, high-strength thin steel plates prepared by the above-mentioned precise heat treatment method.
与现有技术相比，本发明的技术效果为：Compared with the existing technology, the technical effects of the present invention are:
本发明的提供的热处理方法可以解决现有技术中高强度薄钢板热处理过程中易出现的变形、压痕、残余应力大等问题，实现精密协同控性控形，得到的钢板变形小，表面无明显压痕同时机械性能好，并且降低了生产成本，简化了工艺步骤。The heat treatment method provided by the present invention can solve the problems of deformation, indentation, large residual stress, etc. that are prone to occur during the heat treatment of high-strength thin steel plates in the prior art, and achieve precise coordinated controllable shape control. The obtained steel plate has small deformation and no obvious surface. The indentation also has good mechanical properties, reduces production costs and simplifies process steps.
附图说明Description of the drawings
为了更清楚地说明本发明具体实施方式或现有技术中的技术方案，下面将对具体实施方式或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图是本发明的一些实施方式，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。 In order to more clearly explain the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings that need to be used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description The drawings illustrate some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting any creative effort.
图1为本发明实施例提供的低碳低合金高强薄钢板的尺寸示意图；Figure 1 is a schematic dimensional view of a low-carbon, low-alloy, high-strength thin steel plate provided by an embodiment of the present invention;
图2为本发明对比例1中自由淬火条件下钢板淬火变形图片；Figure 2 is a picture of the quenching deformation of the steel plate under free quenching conditions in Comparative Example 1 of the present invention;
图3为本发明对比例2中恒定夹持淬火条件下钢板压痕等缺陷照片；Figure 3 is a photo of defects such as indentation of the steel plate under constant clamping and quenching conditions in Comparative Example 2 of the present invention;
图4为本发明实施例中低碳低合金薄钢板材料连续冷却转变曲线，其中，Ac1:奥氏体开始转变温度，Ac3:奥氏体结束转变温度，Ms：马氏体开始转变温度，Mf：马氏体结束转变温度；Figure 4 is a continuous cooling transformation curve of a low-carbon low-alloy thin steel plate material in an embodiment of the present invention, where Ac1: the starting temperature of austenite transformation, Ac3: the ending temperature of austenite transformation, Ms: the starting temperature of martensite transformation, Mf : Martensite end transformation temperature;
图5为本发明实施例中低碳低合金薄钢板材料等温转变曲线，其中，Ac1:奥氏体开始转变温度，Ac3:奥氏体结束转变温度，Ms：马氏体开始转变温度，Mf：马氏体结束转变温度；Figure 5 is the isothermal transformation curve of the low-carbon low-alloy thin steel plate material in the embodiment of the present invention, where Ac1: the starting temperature of austenite transformation, Ac3: the ending temperature of austenite transformation, Ms: the starting temperature of martensite transformation, Mf: Martensite end transformation temperature;
图6为本发明实施例中不同淬火流量条件下钢板心部温度随时间变化曲线；Figure 6 is a graph showing the temperature change curve of the steel plate core with time under different quenching flow conditions in the embodiment of the present invention;
图7为本发明实施例中钢板变形力随时间变化曲线；Figure 7 is a curve of the deformation force of the steel plate changing with time in the embodiment of the present invention;
图8为本发明实施例中变夹持力淬火钢板夹持力随时间变化曲线；Figure 8 is a variation curve of the clamping force over time of the variable clamping force quenched steel plate in the embodiment of the present invention;
图9为本发明实施例中精确热处理后得到的钢板。Figure 9 is a steel plate obtained after precise heat treatment in an embodiment of the present invention.
具体实施方式Detailed ways
下面将结合实施例对本发明的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。The technical solution of the present invention will be described clearly and completely below with reference to the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.
本发明提供的低碳低合金高强薄钢板的精确热处理方法包括以下步骤：The precise heat treatment method of low-carbon, low-alloy, high-strength thin steel plates provided by the invention includes the following steps:
步骤(a)退火处理，将钢板的组织转变为铁素体和珠光体组织。Step (a) annealing treatment transforms the structure of the steel plate into ferrite and pearlite structures.
该步骤中，退火处理后钢板的组织变为均匀的铁素体和珠 光体组织，提高了钢板成分和组织均匀性，进而提高了步骤(c)中组织转变的均匀性，降低组织应力，减少钢板变形。In this step, the structure of the steel plate after annealing becomes uniform ferrite and beads. The light body structure improves the composition and structural uniformity of the steel plate, thereby improving the uniformity of the structural transformation in step (c), reducing structural stress and reducing deformation of the steel plate.
步骤(b)奥化处理，将步骤(a)中的铁素体和珠光体组织转变为奥氏体组织。Step (b) austenization treatment transforms the ferrite and pearlite structures in step (a) into austenite structures.
该步骤中，奥化处理后钢板组织由退火处理后的铁素体和珠光体转变为奥氏体组织，为步骤(c)夹持淬火处理做组织准备。In this step, the structure of the steel plate after the austenization treatment is transformed from the ferrite and pearlite after the annealing treatment to the austenite structure, preparing the structure for the clamping quenching treatment in step (c).
步骤(c)夹持淬火处理，将步骤(b)中的奥氏体组织转变为马氏体组织，其中，所述钢板的夹持力是变化的。Step (c) is a clamping quenching treatment to transform the austenite structure in step (b) into a martensite structure, wherein the clamping force of the steel plate changes.
该步骤中，钢板组织由奥化处理时的奥氏体全部转变为马氏体组织，钢板夹持力的可调节使得钢板在夹持淬火处理中既被限制变形又可自由伸缩。In this step, the structure of the steel plate is completely transformed from austenite during austenization treatment to martensite structure. The adjustable clamping force of the steel plate makes the steel plate both restricted in deformation and free to expand and contract during the clamping and quenching treatment.
变压力夹持方案既可限制钢板常规自由淬火冷却方法的变形又可避免常规恒定夹持力淬火冷却方法的压痕、划痕等表面缺陷。对钢板的淬火过程分析可知，钢板在夹持淬火过程主要分为如下三个阶段：The variable pressure clamping scheme can not only limit the deformation of the steel plate using the conventional free quenching cooling method, but also avoid surface defects such as indentations and scratches caused by the conventional constant clamping force quenching cooling method. Analysis of the quenching process of the steel plate shows that the clamping quenching process of the steel plate is mainly divided into the following three stages:
(1)初步定形阶段：该阶段钢板处理奥氏体过冷区，强度低塑性好，仅产生热应力，且在该阶段钢板由于冷却收缩钢板从钢板四周往钢板心部收缩，故在此阶段可施加持续较小夹持力(具体夹持力的大小随处理钢板不同的不同)限制变形和避免钢板表面产生压痕缺陷，同时钢板可往心部收缩避免夹持力过大导致的划痕和表面拉应力等缺陷。(1) Preliminary shaping stage: At this stage, the steel plate is processed in the austenite supercooled zone, which has low strength and good plasticity, and only generates thermal stress. In addition, due to the cooling shrinkage of the steel plate at this stage, the steel plate shrinks from the periphery of the steel plate to the center of the steel plate, so at this stage It can apply a continuous small clamping force (the specific clamping force varies depending on the steel plate being processed) to limit deformation and avoid indentation defects on the surface of the steel plate. At the same time, the steel plate can shrink toward the center to avoid scratches caused by excessive clamping force. and surface tensile stress and other defects.
(2)冷却控形阶段：此阶段钢板组织由奥氏体转变为马氏体，钢板强度增大，同时产生组织应力和热应力，应力较大，是钢板控形关键阶段，且在该阶段钢板冷却导致钢板从钢板四周往钢板心部收缩而钢板由奥氏体转变为马氏体体积膨胀导致钢板从钢板心部向钢板四周膨胀，两者可相互抵消部分，故在此阶段可施加较大夹持力(具体夹持力的大小随处理钢板不同的不同)防止钢板变形。(2) Cooling shape control stage: At this stage, the structure of the steel plate changes from austenite to martensite, the strength of the steel plate increases, and structural stress and thermal stress are generated at the same time. The stress is relatively large, which is a critical stage for shape control of the steel plate, and at this stage The cooling of the steel plate causes the steel plate to shrink from the periphery of the steel plate to the center of the steel plate, and the volume expansion of the steel plate changes from austenite to martensite, causing the steel plate to expand from the center of the steel plate to the periphery of the steel plate. The two can partially offset each other, so a greater force can be applied at this stage. The large clamping force (the specific clamping force varies depending on the steel plate being processed) prevents the steel plate from deforming.
(3)尺寸稳定阶段：此阶段钢板组织为马氏体，钢板强度高，但是钢板内外仍存在温差，继续冷却产生热应力，故在此阶段施 加相对较大应力(具体夹持力的大小随处理钢板不同的不同)防止钢板变形。(3) Dimensional stability stage: At this stage, the structure of the steel plate is martensite and the strength of the steel plate is high. However, there is still a temperature difference between the inside and outside of the steel plate, and continued cooling will produce thermal stress. Therefore, the steel plate is applied at this stage. Add relatively large stress (the specific clamping force varies depending on the steel plate being processed) to prevent the steel plate from deforming.
步骤(d)回火处理，将步骤(c)中的马氏体组织转变为回火马氏体组织。Step (d) is a tempering treatment to transform the martensite structure in step (c) into a tempered martensite structure.
该步骤中，钢板由马氏体组织转变为回火马氏体或回火索氏体，使得钢板获得较佳的强韧性综合性能匹配。In this step, the steel plate changes from martensite structure to tempered martensite or tempered sorbite, so that the steel plate can obtain better comprehensive performance matching of strength and toughness.
在优选的实施方式中，上述步骤(c)夹持淬火处理中，夹持力的施用具体可以采用如下方式：In a preferred embodiment, in the clamping and quenching process in step (c) above, the clamping force can be applied in the following manner:
阶段(1)夹持力为奥氏体组织阶段变形力的最大值；Stage (1) The clamping force is the maximum value of the deformation force in the austenite stage;
阶段(2)夹持力为奥氏体转变马氏体阶段变形力的最大值；In stage (2), the clamping force is the maximum value of the deformation force in the austenite transformation to martensite stage;
阶段(3)夹持力为马氏体组织阶段变形力的最大值。The clamping force in stage (3) is the maximum value of the deformation force in the martensite stage.
具体地，夹持力的变化为六段式夹持，分别为变化到阶段(1)的夹持力、阶段(1)的夹持力维持、阶段(1)变化到阶段(2)的夹持力、阶段(2)的夹持力维持、阶段(2)变化到阶段(3)的夹持力、阶段(3)的夹持力维持，其中，“变化到阶段(1)的夹持力”、“阶段(1)变化到阶段(2)的夹持力”以及“阶段(2)变化到阶段(3)的夹持力”，这些夹持力的转换应以尽可能快的方式转换，具体可以以所使用的淬火设备的性能进行调整。Specifically, the change of clamping force is a six-stage clamping, which are the clamping force changing to stage (1), the clamping force maintenance of stage (1), and the clamping force changing from stage (1) to stage (2). Holding force, maintenance of the holding force in stage (2), change of the holding force from stage (2) to stage (3), maintenance of the holding force of stage (3), where, "change to the holding force of stage (1)" "Force", "Clamping force from stage (1) to stage (2)" and "Clamping force from stage (2) to stage (3)", these clamping forces should be converted as quickly as possible Conversion can be adjusted based on the performance of the quenching equipment used.
在优选的实施方式中，在精确热处理该钢板前，需要准备工作如下：In a preferred embodiment, before accurately heat treating the steel plate, the following preparations are required:
(i)获得该钢板的等温转变曲线和连续冷却转变曲线，从而获得全马氏体组织的最小冷却速度、奥氏体结束转变温度、贝氏体开始转变温度、马氏体开始转变温度、马氏体结束转变温度等关键相变温度，指导基于理化试验和数据模拟工艺优化高强薄钢板精确控性控形的步骤(a)中退火处理的加热温度和出炉冷却温度、步骤(b)中奥化处理的加热温度、步骤(c)中水冷温度等。(i) Obtain the isothermal transformation curve and continuous cooling transformation curve of the steel plate, thereby obtaining the minimum cooling rate, austenite end transformation temperature, bainite start transformation temperature, martensite start transformation temperature, martensitic structure Key phase transformation temperatures such as the end-transformation temperature of titanium are used to guide the optimization of the precise shape control of high-strength thin steel plates based on physical and chemical experiments and data simulation processes. The heating temperature and cooling temperature of the annealing treatment in step (a), and the step (b) are in Austria The heating temperature of chemical treatment, the water cooling temperature in step (c), etc.
(ii)运用数值模拟方法获得该钢板优化的淬火工艺参数，该工艺参数应使得钢板转换为全马氏体组织，即获得钢板的最低冷却速度大于上述获得全马氏体组织的最小冷却速度对应的喷水流量和 喷水压力等参数。(ii) Use numerical simulation methods to obtain optimized quenching process parameters for the steel plate. The process parameters should convert the steel plate into a fully martensitic structure, that is, the minimum cooling rate to obtain the steel plate is greater than the minimum cooling rate corresponding to the above-mentioned minimum cooling rate to obtain a fully martensitic structure. of water jet flow and Water spray pressure and other parameters.
(iii)运用数值模拟方法确定钢板在上述淬火过程中变形力演变历程，从而确定上述阶段(1)-(3)中的变形力。(iii) Use numerical simulation methods to determine the evolution of the deformation force of the steel plate during the above quenching process, thereby determining the deformation force in the above stages (1)-(3).
在优选的实施方式中，步骤(c)中夹持淬火处理的操作包括：夹持的钢板以大于马氏体组织最小冷却速度对应的喷水流量和喷水压力进行淬火，冷却至低于马氏体结束转变温度的温度T4。温度T4优选为至少低于马氏体结束转变温度50-80℃，温度T4可以但不限于为至少低于马氏体结束转变温度50℃、55℃、60℃、65℃、70℃、75℃或80℃。In a preferred embodiment, the operation of the clamping quenching treatment in step (c) includes: quenching the clamped steel plate at a water spray flow rate and water spray pressure greater than the minimum cooling rate of the martensitic structure, and cooling to a temperature lower than the martensitic structure. Temperature T4, which is the end temperature of stenite transformation. The temperature T4 is preferably at least 50-80°C lower than the martensite end transformation temperature. The temperature T4 can be, but is not limited to, at least 50°C, 55°C, 60°C, 65°C, 70°C, 75°C lower than the martensite end transformation temperature. ℃ or 80℃.
在优选的实施方式中，步骤(a)中退火处理的操作包括：将钢板加热到高于奥氏体结束转变温度的温度T1保温时间t1，随后冷却至低于贝氏体开始转变温度的温度T2。温度T1优选为高于奥氏体结束转变温度80-100℃，例如80℃、85℃、90℃、95℃或100℃等；时间t1优选为钢板的毫米制厚度的1.5-5倍，需要说明的是，时间t1为分钟制，例如，钢板的厚度如果为10mm，时间t1为15-50min；温度T2优选为至少低于贝氏体开始转变温度80-100℃，例如80℃、85℃、90℃、95℃或100℃等。In a preferred embodiment, the annealing operation in step (a) includes: heating the steel plate to a temperature T1 higher than the austenite end transformation temperature for a holding time t1, and then cooling to a temperature lower than the bainite start transformation temperature. T2. The temperature T1 is preferably 80-100°C higher than the austenite end transformation temperature, such as 80°C, 85°C, 90°C, 95°C or 100°C, etc.; the time t1 is preferably 1.5-5 times the millimeter thickness of the steel plate, as needed It should be noted that time t1 is measured in minutes. For example, if the thickness of the steel plate is 10mm, time t1 is 15-50 minutes; temperature T2 is preferably at least 80-100°C lower than the bainite starting transformation temperature, such as 80°C or 85°C. , 90℃, 95℃ or 100℃, etc.
在优选的实施方式中，步骤(b)中奥化处理的操作包括：将钢板加热到高于奥氏体结束转变温度的温度T3保温时间t2。温度T3优选为高于奥氏体结束转变温度30-80℃，例如30℃、35℃、40℃、45℃、50℃、55℃、60℃、65℃、70℃、75℃或80℃，时间t2优选为钢板的毫米制厚度的1.5-2倍。In a preferred embodiment, the austenizing treatment operation in step (b) includes: heating the steel plate to a temperature T3 higher than the austenite end transformation temperature and a holding time t2. Temperature T3 is preferably 30-80°C higher than the austenite end transformation temperature, such as 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C , time t2 is preferably 1.5-2 times the millimeter thickness of the steel plate.
在优选的实施方式中，步骤(d)中回火处理的操作包括：将钢板加热到180-680℃，保温时间t3，时间t3为钢板的毫米制厚度的10-30倍。钢板的加热温度可以但不限于为180℃、280℃、380℃、480℃、580℃或680℃。In a preferred embodiment, the tempering treatment operation in step (d) includes: heating the steel plate to 180-680°C for a holding time t3, where the time t3 is 10-30 times the millimeter thickness of the steel plate. The heating temperature of the steel plate may be, but is not limited to, 180°C, 280°C, 380°C, 480°C, 580°C or 680°C.
在更优选的实施方式中，低碳低合金高强薄钢板的精确热处理方法如下：In a more preferred embodiment, the precise heat treatment method of low-carbon, low-alloy, high-strength thin steel plates is as follows:
第一阶段，基于理化试验和数据模拟工艺优化： The first stage is based on physical and chemical tests and data simulation process optimization:
步骤1，获得低碳低合金高强薄钢板对应材料的等温转变曲线和连续冷却转变曲线；指导基于理化试验和数据模拟工艺优化高强薄钢板精确控性控形(第二阶段)中步骤(a)退火处理的加热温度和出炉冷却温度、步骤(b)奥化处理的加热温度、步骤(c)中水冷温度。Step 1: Obtain the isothermal transformation curve and continuous cooling transformation curve of the corresponding material of the low-carbon, low-alloy high-strength thin steel plate; guide step (a) in optimizing the precise controllability and shape control of the high-strength thin steel plate (second phase) based on physical and chemical tests and data simulation processes The heating temperature of the annealing treatment and the cooling temperature of the furnace, the heating temperature of the Austrian treatment in step (b), and the water cooling temperature in step (c).
步骤2，运用数值模拟方法获得低碳低合金薄钢板优化的淬火工艺参数；可指导基于理化试验和数据模拟工艺优化高强薄钢板精确控性控形(第二阶段)中步骤(c)中喷淋系统参数的设计。Step 2: Use numerical simulation methods to obtain optimized quenching process parameters for low-carbon and low-alloy thin steel plates; this can guide the spraying in step (c) of step (c) of high-strength thin steel plates based on physical and chemical tests and data simulation processes to optimize the precise shape and shape control of high-strength thin steel plates (the second phase). Design of shower system parameters.
步骤3，运用数值模拟方法确定钢板在上述淬火过程中变形力演变历程；Step 3: Use numerical simulation methods to determine the evolution of the deformation force of the steel plate during the above quenching process;
步骤4，在步骤3的基础上，结合钢板淬火冷却理论和作用力与反作用力原理，获得低碳低合金高强薄板夹持力的最优值。可指导基于理化试验和数据模拟工艺优化高强薄钢板精确控性控形(第二阶段)中步骤(c)中夹持力的优化设计。Step 4. On the basis of Step 3, combined with the steel plate quenching cooling theory and the principle of action and reaction force, obtain the optimal value of the clamping force of low-carbon, low-alloy, high-strength thin plates. It can guide the optimization design of the clamping force in step (c) of the high-strength thin steel plate in step (c) based on physical and chemical tests and data simulation processes.
第二阶段，高强薄钢板变压力夹持夹持淬火处理：In the second stage, the high-strength thin steel plate is clamped and quenched with variable pressure:
步骤(a)，退火处理，将钢板加热至某一温度T1保温一段时间t1，随后随炉冷却至某一温度T2出炉冷却；Step (a), annealing treatment, the steel plate is heated to a certain temperature T1 and kept for a period of time t1, and then cooled in the furnace to a certain temperature T2 and cooled out of the furnace;
步骤(b)，奥化处理，将钢板加热至某一温度T3保温一段时间t2；Step (b), Austrian treatment, heating the steel plate to a certain temperature T3 and holding it for a period of time t2;
步骤(c)，夹持淬火处理，将钢板快速转移至淬火设备中，淬火设备将钢板夹持，启动喷淋系统将钢板水冷至某一温度T4；淬火烈度根据基于理化实验和数值模拟工艺优化(第一阶段)的步骤2确定，如此既可使得钢板在步骤(c)夹持淬火处理过程中全部转变为马氏体又可避免因过大的冷速产生大应力导致的大淬火畸变；淬火设备施加给钢板的夹持力根据基于理化实验和数值模拟工艺优化(第一阶段)的步骤3和4确定并设计优化的变压力夹持变压力夹持方式，这样钢板在步骤(c)夹持淬火处理过程中既被限制变形又可自由伸缩。Step (c), clamping quenching treatment, quickly transfer the steel plate to the quenching equipment, the quenching equipment clamps the steel plate, starts the spray system to water-cool the steel plate to a certain temperature T4; the quenching intensity is optimized based on physical and chemical experiments and numerical simulation processes Step 2 of (the first stage) is determined so that the steel plate can be completely transformed into martensite during the clamping quenching process in step (c) and avoid large quenching distortion caused by large stress caused by excessive cooling rate; The clamping force exerted by the quenching equipment on the steel plate is determined and optimized according to steps 3 and 4 of the process optimization (first phase) based on physical and chemical experiments and numerical simulations, and the optimized variable pressure clamping method is designed, so that the steel plate is in step (c) During the clamping and quenching process, the deformation is restricted but can be freely expanded and contracted.
步骤(d)，回火处理，将钢板加热至某一温度保温一段时 间t3，使得钢板获得较佳的强韧性综合性能匹配。Step (d), tempering treatment, heating the steel plate to a certain temperature and keeping it warm for a period of time The interval t3 enables the steel plate to obtain better comprehensive performance matching of strength and toughness.
本发明提供的方法中，夹持淬火处理中淬火工艺参数可以调控钢板的组织/性能，使得低碳低合金薄钢板整体淬火成高强度马氏体。变化夹持力可防止钢板在淬火过程产生大的热处理变形和表面压痕、划痕等问题。In the method provided by the invention, the quenching process parameters in the clamping quenching process can regulate the structure/properties of the steel plate, so that the low-carbon low-alloy thin steel plate is quenched into high-strength martensite as a whole. Changing the clamping force can prevent the steel plate from causing large heat treatment deformation and surface indentations, scratches and other problems during the quenching process.
本发明还提供上述方法制备得到的低碳低合金高强薄钢板，性能与外观皆优。The invention also provides a low-carbon, low-alloy, high-strength thin steel plate prepared by the above method, which has excellent performance and appearance.
下面通过实施例对本发明作进一步说明。如无特别说明，实施例中的材料为根据现有方法制备而得，或直接从市场上购得。The present invention will be further described below through examples. Unless otherwise specified, the materials in the examples were prepared according to existing methods or purchased directly from the market.
实施例Example
低碳低合金薄钢板尺寸如图1所示，钢板长12000mm，宽2000mm，厚10mm。钢板化学成分如表1所示。The dimensions of the low carbon low alloy thin steel plate are shown in Figure 1. The steel plate is 12000mm long, 2000mm wide and 10mm thick. The chemical composition of the steel plate is shown in Table 1.
表1低碳低合金薄钢板化学成分(质量分数，wt％)
Table 1 Chemical composition of low carbon low alloy thin steel plate (mass fraction, wt%)
基于理化实验和数值模拟工艺优化(第一阶段)包括如下步骤：Process optimization (first phase) based on physical and chemical experiments and numerical simulations includes the following steps:
步骤1，通过理化实验获得低碳低合金高强钢板材料的连续冷却转变曲线(图4)和等温转变曲线(图5)；由此可得钢板材料的奥氏体结束转变温度为820℃，贝氏体开始转变温度为500℃，马氏体开始转变温度为340℃，马氏体结束转变温度为200℃，获得全马氏体组织的最小冷却速度V临为40℃/s。Step 1: Obtain the continuous cooling transformation curve (Figure 4) and isothermal transformation curve (Figure 5) of the low-carbon, low-alloy high-strength steel plate material through physical and chemical experiments; it can be obtained that the austenite end transformation temperature of the steel plate material is 820°C. The starting temperature of martensite transformation is 500°C, the starting temperature of martensite transformation is 340°C, the ending temperature of martensite transformation is 200°C, and the minimum cooling rate VLin to obtain a full martensite structure is 40°C/s.
步骤2，运用数值模拟方法获得低碳低合金薄钢板优化的淬火工艺参数；设计了三种淬火工艺方案——淬火工艺方案一：淬火流量为5L/m2*s、淬火压力为0.2MPa；淬火工艺方案二：淬火流量为10L/m2*s、淬火压力为0.2MPa；淬火工艺方案三：淬火流量为15L/m2*s、淬火压力为0.2MPa。不同淬火工艺方案下钢板心部的温度随时间变化曲线如图6所示。 Step 2: Use numerical simulation methods to obtain optimized quenching process parameters for low carbon and low alloy thin steel plates; design three quenching process plans - quenching process plan 1: quenching flow rate is 5L/m 2 *s, quenching pressure is 0.2MPa; Quenching process plan two: quenching flow rate is 10L/m 2 *s, quenching pressure is 0.2MPa; quenching process plan three: quenching flow rate is 15L/m 2 *s, quenching pressure is 0.2MPa. The temperature variation curve of the steel plate core with time under different quenching process schemes is shown in Figure 6.
由此可见，在淬火工艺方案为5L/m2*s时，钢板心部的冷速约为25℃/s，小于步骤1中的连续冷却转变曲线中转变为获得全马氏体组织的最小冷却速度V临为40℃/s，故钢板在此淬火工艺条件下无法获得所需的马氏体组织；淬火工艺方案为10L/m2*s时，钢板心部的冷速约为45℃/s，稍大于步骤1中的连续冷却转变曲线中转变为获得全马氏体组织的最小冷却速度V临为40℃/s，故在此工艺条件下钢板能获得所需的马氏体组织；淬火工艺方案为20L/m2*s时，钢板心部的冷速约为98℃/s，大于步骤1中的连续冷却转变曲线中转变为获得全马氏体组织的最小冷却速度V临为40℃/s，在此工艺条件下钢板可获得所需的马氏体组织。结合实际生产，为节约淬火水和便于淬火过程的操作，淬火工艺选择淬火工艺方案二，淬火流量为10L/m2*s、淬火压力为0.2MPa。It can be seen that when the quenching process plan is 5L/m 2 *s, the cooling rate at the center of the steel plate is about 25°C/s, which is less than the minimum value required to obtain a full martensitic structure in the continuous cooling transformation curve in step 1. The cooling rate V is 40°C/s, so the steel plate cannot obtain the required martensite structure under this quenching process condition; when the quenching process plan is 10L/m 2 *s, the cooling rate at the center of the steel plate is about 45°C /s, slightly larger than the minimum cooling rate VLin in the continuous cooling transformation curve in step 1 to obtain a full martensite structure is 40°C/s, so the steel plate can obtain the required martensite structure under this process condition ; When the quenching process plan is 20L/m 2 *s, the cooling rate at the center of the steel plate is about 98°C/s, which is greater than the minimum cooling rate V Pro in the continuous cooling transformation curve in step 1 to obtain a full martensitic structure. The temperature is 40℃/s. Under this process condition, the steel plate can obtain the required martensite structure. Based on actual production, in order to save quenching water and facilitate the operation of the quenching process, the quenching process option 2 is selected. The quenching flow rate is 10L/m 2 *s and the quenching pressure is 0.2MPa.
步骤3，运用数值模拟方法确定钢板在上述淬火过程中变形力演变历程，如图7所示。淬火中最大变形力为158KN，且变形力不断变化。Step 3: Use numerical simulation methods to determine the evolution of the deformation force of the steel plate during the above quenching process, as shown in Figure 7. The maximum deformation force during quenching is 158KN, and the deformation force changes continuously.
步骤4，在步骤3的基础上，结合钢板淬火冷却理论和作用力与反作用力原理，获得低碳低合金高强薄板夹持力的最优值如图8所示(为奥氏体、奥氏体转变马氏体、马氏体，三个状态下变形力的最大值)，在从0s到1s内夹持力增加至70KN，在1s到5s之间夹持力保持为70KN，从5s到10s夹持力从70KN增加至158KN，在10s到16s之间夹持力保持为158KN，从16s到20s内夹持力从158KN降低至90KN，在20s到30s夹持力保持为90KN。Step 4. On the basis of step 3, combined with the steel plate quenching cooling theory and the principle of action and reaction force, the optimal value of the clamping force of low-carbon low-alloy high-strength thin plate is obtained, as shown in Figure 8 (for austenite, austenite Body transformation martensite, martensite, the maximum deformation force in the three states), the clamping force increases to 70KN from 0s to 1s, the clamping force remains at 70KN from 1s to 5s, and the clamping force remains at 70KN from 5s to 5s. The clamping force increases from 70KN to 158KN in 10s, the clamping force remains at 158KN between 10s and 16s, the clamping force decreases from 158KN to 90KN from 16s to 20s, and the clamping force remains at 90KN from 20s to 30s.
高强薄钢板变压力夹持淬火处理(第二阶段)包括如下步骤：The variable pressure clamping quenching treatment (second stage) of high-strength thin steel plates includes the following steps:
步骤(a)，退火处理，将钢板加热至900℃保温一段时间30min，随后随炉冷却至400℃出炉冷却；Step (a), annealing treatment, the steel plate is heated to 900°C and kept for 30 minutes, and then cooled to 400°C and cooled out of the furnace;
步骤(b)，奥化处理，将钢板加热至某一温度860℃保温18min；Step (b), Austrian treatment, heat the steel plate to a certain temperature of 860°C and keep it for 18 minutes;
步骤(c)，夹持淬火处理，将钢板快速转移至淬火设备中， 淬火设备将钢板夹持，设置的夹持力为：在从0s到1s内夹持力增加至70KN，在1s到5s之间夹持力保持为70KN，从5s到10s夹持力从70KN增加至158KN，在10s到16s之间夹持力保持为158KN，从16s到20s内夹持力从158KN降低至90KN，在20s到30s夹持力保持为90KN；启动喷淋系统(淬火流量为10L/m2*s、淬火压力为0.2MPa)将钢板水冷却30s，钢板冷却至30℃；Step (c), clamp and quench the steel plate, quickly transfer the steel plate to the quenching equipment, The quenching equipment clamps the steel plate. The clamping force is set as follows: the clamping force increases to 70KN from 0s to 1s, the clamping force remains at 70KN from 1s to 5s, and the clamping force increases from 70KN from 5s to 10s. to 158KN, the clamping force remains at 158KN from 10s to 16s, the clamping force decreases from 158KN to 90KN from 16s to 20s, and the clamping force remains at 90KN from 20s to 30s; start the spray system (quenching flow is 10L /m 2 *s, quenching pressure is 0.2MPa) water-cool the steel plate for 30s, and cool the steel plate to 30°C;
步骤(d)，回火处理，将钢板加热至200℃，并保温200min。Step (d), tempering treatment, heat the steel plate to 200°C and keep it warm for 200 minutes.
经检测，运用如上实施例的技术，获得的钢板变形小，最大为10mm，表面无明显压痕等缺陷，如图9所示，屈服强度约为1500MPa，抗拉强度约为1750MPa，延伸率为15％～17％，实现了低碳低合金高强薄钢板精确热处理。After testing, using the technology of the above embodiment, the steel plate obtained has small deformation, up to 10mm, and no obvious defects such as indentation on the surface. As shown in Figure 9, the yield strength is about 1500MPa, the tensile strength is about 1750MPa, and the elongation is 15% to 17%, achieving precise heat treatment of low-carbon, low-alloy, high-strength thin steel plates.
对比例1Comparative example 1
采用如实施例中的钢板，操作流程参照实施例(步骤(a)-步骤(d))进行，其中，不同的是，步骤(c)中采用的是钢板自由淬火，具体为在淬火流量为10L/m2*s、淬火压力为0.2MPa的淬火工艺条件下进行自由淬火，在自由淬火条件下钢板变形图如图2所示。由此可见，在该淬火工艺下，钢板发生明显变形，无法满足使用要求。Using the steel plate as in the embodiment, the operation process is carried out with reference to the embodiment (step (a)-step (d)). The difference is that in step (c), the steel plate is free quenched. Specifically, the quenching flow rate is Free quenching is performed under the quenching process conditions of 10L/m 2 *s and quenching pressure of 0.2MPa. The deformation diagram of the steel plate under free quenching conditions is shown in Figure 2. It can be seen that under this quenching process, the steel plate is significantly deformed and cannot meet the usage requirements.
对比例2Comparative example 2
采用如实施例中的钢板，操作流程参照实施例(步骤(a)-步骤(d))进行，其中，不同的是，步骤c中采用的是钢板恒定夹持淬火，淬火流量为10L/m2*s、淬火压力为0.2MPa、淬火过程恒定夹持力为158000N的淬火工艺条件下进行恒定夹持淬火，在恒定夹持淬火条件下所得钢板如图3所示。由此可见，在该淬火工艺条件下，钢板表面产生明显的压痕等缺陷，影响外观质量，不满足使用要求。Using the steel plate as in the embodiment, the operation process is carried out with reference to the embodiment (step (a)-step (d)). The difference is that in step c, the steel plate is constantly clamped and quenched, and the quenching flow rate is 10L/m Constant clamping quenching is performed under the quenching process conditions of 2 *s, quenching pressure is 0.2MPa, and constant clamping force during quenching is 158000N. The steel plate obtained under constant clamping quenching conditions is shown in Figure 3. It can be seen that under this quenching process condition, obvious defects such as indentations are produced on the surface of the steel plate, which affects the appearance quality and does not meet the usage requirements.
最后应说明的是：以上各实施例仅用以说明本发明的技术方案，而非对其限制；尽管参照前述各实施例对本发明进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本 发明各实施例技术方案的范围。 Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, but not to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or to equivalently replace some or all of the technical features; and these modifications or substitutions do not deviate from the essence of the corresponding technical solutions. The scope of the technical solutions of each embodiment of the invention.

Claims (10)

  1. 一种低碳低合金高强薄钢板的精确热处理方法，其特征在于，包括如下步骤：A precise heat treatment method for low-carbon, low-alloy, high-strength thin steel plates, which is characterized by including the following steps:
    步骤(a)退火处理，将所述钢板的组织转变为铁素体和珠光体组织；Step (a) annealing treatment to transform the structure of the steel plate into ferrite and pearlite structures;
    步骤(b)奥化处理，将步骤(a)中的铁素体和珠光体组织转变为奥氏体组织；Step (b) austenization treatment, transforming the ferrite and pearlite structures in step (a) into austenite structures;
    步骤(c)夹持淬火处理，将步骤(b)中的奥氏体组织转变为马氏体组织，其中，所述钢板的夹持力是变化的；Step (c) clamping quenching treatment to transform the austenite structure in step (b) into a martensite structure, wherein the clamping force of the steel plate changes;
    步骤(d)回火处理，将步骤(c)中的马氏体组织转变为回火马氏体组织。Step (d) is a tempering treatment to transform the martensite structure in step (c) into a tempered martensite structure.
  2. 根据权利要求1所述的精确热处理方法，其特征在于，所述步骤(c)夹持淬火处理中，所述夹持力的施用分为如下阶段(1)-(3)：The precise heat treatment method according to claim 1, characterized in that in the clamping and quenching treatment in step (c), the application of the clamping force is divided into the following stages (1)-(3):
    阶段(1)夹持力为奥氏体组织阶段变形力的最大值；Stage (1) The clamping force is the maximum value of the deformation force in the austenite stage;
    阶段(2)夹持力为奥氏体转变马氏体阶段变形力的最大值；In stage (2), the clamping force is the maximum value of the deformation force in the austenite transformation to martensite stage;
    阶段(3)夹持力为马氏体组织阶段变形力的最大值；In stage (3), the clamping force is the maximum value of the deformation force in the martensite stage;
    所述变形力由所述钢板在淬火过程中变形力演变历程确定。The deformation force is determined by the evolution of the deformation force of the steel plate during the quenching process.
  3. 根据权利要求2所述的精确热处理方法，其特征在于，所述步骤(c)中夹持淬火处理的操作包括：夹持的钢板以大于马氏体组织最小冷却速度对应的喷水流量和喷水压力进行淬火，冷却至低于马氏体结束转变温度的温度T4；The precise heat treatment method according to claim 2, characterized in that the operation of clamping and quenching treatment in step (c) includes: the clamped steel plate is sprayed with a water spray flow rate and a spray rate that are greater than the minimum cooling rate of the martensitic structure. Quench by water pressure and cool to a temperature T4 lower than the end temperature of martensite transformation;
    所述温度T4至少低于马氏体结束转变温度50-80℃。The temperature T4 is at least 50-80°C lower than the end temperature of martensite transformation.
  4. 根据权利要求1所述的精确热处理方法，其特征在于，所述步骤(a)中退火处理的操作包括：将所述钢板加热到高于奥氏体结束转变温度的温度T1保温时间t1，随后冷却至低于贝氏体开始转变温度的温度T2。The precise heat treatment method according to claim 1, characterized in that the annealing operation in step (a) includes: heating the steel plate to a temperature T1 higher than the austenite end transformation temperature for a holding time t1, and then Cool to a temperature T2 lower than the temperature at which bainite transformation begins.
  5. 根据权利要求5所述的精确热处理方法，其特征在于，所述 温度T1高于奥氏体结束转变温度80-100℃，所述时间t1为所述钢板的毫米制厚度的1.5-5倍；The precise heat treatment method according to claim 5, characterized in that: The temperature T1 is 80-100°C higher than the austenite end transformation temperature, and the time t1 is 1.5-5 times the millimeter thickness of the steel plate;
    所述温度T2至少低于贝氏体开始转变温度80-100℃。The temperature T2 is at least 80-100°C lower than the starting temperature of bainite transformation.
  6. 根据权利要求1所述的精确热处理方法，其特征在于，所述步骤(b)中奥化处理的操作包括：将所述钢板加热到高于奥氏体结束转变温度的温度T3保温时间t2。The precise heat treatment method according to claim 1, characterized in that the operation of austenization treatment in step (b) includes: heating the steel plate to a temperature T3 higher than the austenite end transformation temperature and a holding time t2.
  7. 根据权利要求6所述的精确热处理方法，其特征在于，所述温度T3高于奥氏体结束转变温度30-80℃，所述时间t2为所述钢板的毫米制厚度的1.5-2倍。The precise heat treatment method according to claim 6, characterized in that the temperature T3 is 30-80°C higher than the austenite end transformation temperature, and the time t2 is 1.5-2 times the millimeter thickness of the steel plate.
  8. 根据权利要求1所述的精确热处理方法，其特征在于，所述步骤(d)中回火处理的操作包括：将所述钢板加热到180-680℃，保温时间t3，所述时间t3为所述钢板的毫米制厚度的10-30倍。The precise heat treatment method according to claim 1, characterized in that the tempering operation in step (d) includes: heating the steel plate to 180-680°C for a holding time t3, and the time t3 is 10-30 times the millimeter thickness of the steel plate.
  9. 根据权利要求1-8任一项所述的精确热处理方法，其特征在于，在所述步骤(a)之前还包括检测所述钢板的等温转变曲线和连续冷却转变曲线的步骤。The precise heat treatment method according to any one of claims 1 to 8, characterized in that, before step (a), it also includes the step of detecting the isothermal transformation curve and the continuous cooling transformation curve of the steel plate.
  10. 权利要求1-9任一项所述的精确热处理方法制备得到的低碳低合金高强薄钢板。 A low-carbon, low-alloy, high-strength thin steel plate prepared by the precise heat treatment method described in any one of claims 1-9.
PCT/CN2023/075923 2022-05-06 2023-02-14 Accurate heat treatment method for low-carbon low-alloy high-strength thin steel plate WO2023213109A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
ZA2023/06225A ZA202306225B (en) 2022-05-06 2023-06-13 Precise heat treatment method for low-carbon low-alloy highstrength thin steel sheets

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202210483543.8A CN114921638B (en) 2022-05-06 2022-05-06 Accurate heat treatment method for low-carbon low-alloy high-strength thin steel plate
CN202210483543.8 2022-05-06

Publications (1)

Publication Number Publication Date
WO2023213109A1 true WO2023213109A1 (en) 2023-11-09

Family

ID=82806256

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2023/075923 WO2023213109A1 (en) 2022-05-06 2023-02-14 Accurate heat treatment method for low-carbon low-alloy high-strength thin steel plate

Country Status (3)

Country Link
CN (1) CN114921638B (en)
WO (1) WO2023213109A1 (en)
ZA (1) ZA202306225B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117802446A (en) * 2024-03-01 2024-04-02 山东天瑞重工有限公司 Heat treatment process method of low-carbon high-alloy structural steel and hydraulic breaking hammer piston

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114921638B (en) * 2022-05-06 2023-11-03 中国机械总院集团北京机电研究所有限公司 Accurate heat treatment method for low-carbon low-alloy high-strength thin steel plate

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3467367A (en) * 1966-09-19 1969-09-16 Wilson Eng Co Inc Lee Quench press
JP2002275603A (en) * 2001-03-16 2002-09-25 Kobe Steel Ltd Process and cooling device for press quenching of heat- treated aluminum alloy extruded material
CN102776337A (en) * 2012-08-21 2012-11-14 重庆大江工业有限责任公司 Press quenching and processing method for 30 MnCrNiMo armored steel plate part
CN103740898A (en) * 2014-01-02 2014-04-23 内蒙古北方重工业集团有限公司 Pressure quenching method of high-hardness 5Cr13MoV wearable liner
CN104372157A (en) * 2014-11-14 2015-02-25 哈尔滨东安发动机（集团）有限公司 Thermal treatment deformation control method for duplicate spiral bevel gear
CN109097551A (en) * 2018-09-21 2018-12-28 重庆齿轮箱有限责任公司 A kind of elongated gear shaft heat-treatment distortion control process
CN109234504A (en) * 2018-10-23 2019-01-18 北京航星机器制造有限公司 A kind of automatic press quenching integrated apparatus of electric heating
CN110079741A (en) * 2019-06-19 2019-08-02 本钢板材股份有限公司 A kind of armour plate and its manufacturing method
CN114921638A (en) * 2022-05-06 2022-08-19 北京机电研究所有限公司 Accurate heat treatment method for low-carbon low-alloy high-strength thin steel plate

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5835574B2 (en) * 1980-03-13 1983-08-03 川崎製鉄株式会社 How to harden steel pipes
US9896736B2 (en) * 2010-10-22 2018-02-20 Nippon Steel & Sumitomo Metal Corporation Method for manufacturing hot stamped body having vertical wall and hot stamped body having vertical wall
MX361834B (en) * 2010-10-22 2018-12-18 Nippon Steel & Sumitomo Metal Corp Steel sheet and steel sheet production process.
CN102494106A (en) * 2011-12-26 2012-06-13 重庆清平机械厂 Process for manufacturing 20 CrMo carburizing steel gear
DE102013010946B3 (en) * 2013-06-28 2014-12-31 Daimler Ag Method and plant for producing a press-hardened sheet steel component
CN106755805A (en) * 2016-12-15 2017-05-31 通裕重工股份有限公司 A kind of heat treatment after forging technique of low-alloy carburizing steel
CN108285952A (en) * 2018-01-28 2018-07-17 合肥市瑞宏重型机械有限公司 The method of stepped quenching by high pressure gas
CN112359181A (en) * 2020-04-15 2021-02-12 厦门澄志精密科技有限公司 Template quenching device
CN113528761A (en) * 2021-06-16 2021-10-22 首钢集团有限公司 Hot-formed part and preparation method thereof

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3467367A (en) * 1966-09-19 1969-09-16 Wilson Eng Co Inc Lee Quench press
JP2002275603A (en) * 2001-03-16 2002-09-25 Kobe Steel Ltd Process and cooling device for press quenching of heat- treated aluminum alloy extruded material
CN102776337A (en) * 2012-08-21 2012-11-14 重庆大江工业有限责任公司 Press quenching and processing method for 30 MnCrNiMo armored steel plate part
CN103740898A (en) * 2014-01-02 2014-04-23 内蒙古北方重工业集团有限公司 Pressure quenching method of high-hardness 5Cr13MoV wearable liner
CN104372157A (en) * 2014-11-14 2015-02-25 哈尔滨东安发动机（集团）有限公司 Thermal treatment deformation control method for duplicate spiral bevel gear
CN109097551A (en) * 2018-09-21 2018-12-28 重庆齿轮箱有限责任公司 A kind of elongated gear shaft heat-treatment distortion control process
CN109234504A (en) * 2018-10-23 2019-01-18 北京航星机器制造有限公司 A kind of automatic press quenching integrated apparatus of electric heating
CN110079741A (en) * 2019-06-19 2019-08-02 本钢板材股份有限公司 A kind of armour plate and its manufacturing method
CN114921638A (en) * 2022-05-06 2022-08-19 北京机电研究所有限公司 Accurate heat treatment method for low-carbon low-alloy high-strength thin steel plate

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117802446A (en) * 2024-03-01 2024-04-02 山东天瑞重工有限公司 Heat treatment process method of low-carbon high-alloy structural steel and hydraulic breaking hammer piston

Also Published As

Publication number Publication date
ZA202306225B (en) 2024-07-31
CN114921638A (en) 2022-08-19
CN114921638B (en) 2023-11-03

Similar Documents

Publication Publication Date Title
WO2023213109A1 (en) Accurate heat treatment method for low-carbon low-alloy high-strength thin steel plate
US4619714A (en) Controlled rolling process for dual phase steels and application to rod, wire, sheet and other shapes
CN107794357A (en) The method of super rapid heating technique productions superhigh intensity martensite cold-rolled steel sheet
CN109252107B (en) Production method of high-flatness ultrahigh-strength steel
CN105506249A (en) Heat treatment method for high-nitrogen corrosion resistant plastic die steel
CN104593573A (en) Combined thermomechanical treatment strengthening method for efficiently improving strength and toughness of non-quenched and tempered steel
CN105689611A (en) Machining technology for single-end spline shaft sleeve
CN101538643A (en) Process for quenching H13 steel by high-pressure gas stepped quick cooling
WO2022166038A1 (en) Hot rolled high strength steel long-shank bolt and manufacturing method therefor
CN117265362A (en) Production method of non-quenched and tempered wire rod for 10.9-grade high-plasticity standard component
CN109680127B (en) Quenching and tempering process for large-size medium-carbon alloy structural round steel
CN110791621A (en) Heat treatment method for torsion beam for vehicle
CN102936695A (en) High-strength low-temperature pressure vessel steel plate and production method thereof
CN114941068B (en) Preparation method of rare earth microalloyed high-toughness 960 MPa-level ultrahigh-strength steel
KR102465476B1 (en) In-line manufacturing method of steel tube
CN105755266A (en) Gear quenching technology
CN111945077B (en) Steel Q890D for ultra-high-strength engineering machinery and production method thereof
US20220235429A1 (en) Cold-rolling strip steel with strength and hardness thereof varying in thickness direction and manufacturing method therefor
JPH04143225A (en) Manufacture of long size steel with different strength in longitudinal direction
JPS61153230A (en) Production of low-alloy steel wire rod which permits quick spheroidization
CN104531965A (en) Method for heat treatment of high-plasticity low-yield-ratio concrete reinforcing bars
JP2000328141A (en) Heat treatment method to manufacture long product or flat product of alloy-free or low-alloy steel with hardened surface layer
CN111041362B (en) Method for improving steel ladle simmer effect of non-quenched and tempered bolt
US3196053A (en) Production of heat-treated sheets
US20080257460A1 (en) Method of producing forgings having excellent tensile strength and elongation from steel wire rods

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23799099

Country of ref document: EP

Kind code of ref document: A1