Laser compounding-rolling annealing method for high-strength stainless steel composite plate

Abstract

The invention discloses a laser compounding-rolling annealing method for a high-strength steel and stainless steel composite board, which is characterized in that the surface of stainless steel is subjected to nanocrystallization strengthening through ultrasonic rolling, the surface layer of the high-strength steel is subjected to precise temperature control softening by combining a copper integral mirror homogenization laser spot, the hardness difference between the stainless steel and the high-strength steel is reduced to be less than or equal to 30%, and the deformation coordination is obviously improved; the auxiliary composite laser beams are synchronously applied to complete rolling compounding, warm-pressing annealing and online flattening are integrated, compounding, annealing and flattening continuity is achieved, 3-5 procedures are reduced, and the short process is achieved; the thermal-mechanical coupling effect in the warm-pressing annealing process promotes interface atom diffusion, a continuous solid solution structure is formed, and the interface bonding strength is further improved; the method is suitable for compounding of 500-1000 MPa high-strength steel and austenite / duplex stainless steel, the adjustable range of parameters is wide, and efficient production of plates with the thickness of 1-5 mm is supported.

Description

Technical Field

[0001] The present invention relates to the technical field of rolling of metal composite plates, and particularly relates to a method for laser composite-roll pressing annealing of high-strength steel and stainless steel composite plates. Background Art

[0002] Carbon steel and stainless steel composite plates have both the excellent mechanical properties of carbon steel and the corrosion resistance of stainless steel, and are widely used in fields such as petrochemical industry, ocean engineering, and aerospace. However, with the continuous improvement of the requirements for material properties in modern industry, the strength of traditional carbon steel and stainless steel composite plates is difficult to meet the lightweight, high load-bearing, and long-life requirements of high-end equipment. Therefore, high-strength steel and stainless steel composite plates have become an important development direction, which need to achieve higher strength while maintaining excellent corrosion resistance.

[0003] However, the existing processes are not applicable to the composite of high-strength steel and stainless steel with large strength differences and small melting point differences. Specifically, on the one hand, the existing composite processes are only applicable to steel and stainless steel with relatively small strength differences. For example, the patent with the application number 202311553020.7 proposes a method for preparing a low-alloy / stainless steel composite steel coil. By obtaining a single-sided stainless steel slab, heating, seven passes of rough rolling, finish rolling, and coiling, a low-alloy steel / stainless steel composite plate is prepared. However, the strength of the low-alloy steel on the stainless steel side phase in this method is relatively low. If the low-alloy steel is replaced with high-strength steel, the composite quality of the stainless steel layer of the prepared composite plate is insufficient, affecting the corrosion resistance. On the other hand, the patent with the application number 202411698282.7 proposes a method for rolling extra-thick stainless steel composite plates and its production method. Through blank welding composite, vacuum pumping, controlled rolling, and temper heat treatment, a stainless steel composite plate with a tensile strength > 550 MPa is finally obtained. However, this method needs to be transferred between different processes, and the efficiency is not high.

[0004] Therefore, the present invention proposes a method for laser composite-roll pressing annealing of high-strength steel and stainless steel composite plates, aiming to solve the problems of coordinated deformation and metallurgical bonding between high-strength steel plates and stainless steel plates with large strength differences, and realizing the efficient and high-quality composite processing of high-strength steel plates and stainless steel plates with high shear strength. Summary of the Invention

[0005] In order to solve the problems of coordinated deformation and metallurgical bonding between high-strength steel and stainless steel with large strength differences in the existing rolling composite process, the present invention provides a method for laser composite-roll pressing annealing of high-strength steel and stainless steel composite plates. Through the synergistic treatment of stainless steel nanocrystallization strengthening and high-strength steel laser softening, the hardness difference is reduced, and the problem of coordinated deformation is solved. Through the integrated treatment of laser composite-roll pressing annealing, the composite, annealing, and leveling are completed online, the process flow is reduced, and short-process and high-efficiency production are realized. The interfacial bonding strength of the composite plate is high.

[0006] To achieve the above object, the present invention adopts the following technical solutions: The present invention provides a laser composite-roll pressing annealing method for high-strength steel and stainless steel composite plates, comprising the following steps: S1. Nanocrystallization treatment of the stainless steel surface: The surface of the stainless steel plate to be composite is strengthened by an ultrasonic rolling device. After treatment, the microhardness of the surface of the stainless steel plate to be composite is 220-380 HV, and the depth of the treatment layer is 150-200 μm; S2. Laser pretreatment of the high-strength steel surface: A copper integral mirror is used to homogenize the energy distribution of the light spot to obtain a preheating light spot with a flat-top energy distribution. Combined with a pyrometer for temperature control, the surface of the high-strength steel plate to be composite is softened by pretreatment. After treatment, the microhardness of the surface of the high-strength steel plate to be composite is reduced to 200-400 HV; S3. Laser composite: The surface-hardened stainless steel plate treated by the ultrasonic rolling device and the high-strength steel plate softened by laser irradiation on the surface are fed into a composite roll. Under the action of an auxiliary composite processing laser beam, layered composite is realized to obtain a high-strength steel and stainless steel composite plate; S4. Online roll pressing annealing: The high-strength steel and stainless steel composite plate after laser composite processing enters a roll pressing annealing device to simultaneously improve the bonding strength of the composite plate, anneal and flatten it.

[0007] Adopting the above technical solutions: The ultrasonic rolling device applies high-frequency vibration (20-40 kHz) and static pressure (200-400 N) to the surface of the stainless steel plate to be composite, generating severe plastic deformation on the surface layer to form a nanocrystalline structure, significantly increasing the hardness of the surface of the stainless steel plate to be composite to 220-380 HV, and at the same time controlling the depth of the strengthening layer (150-200 μm). At the same time, a copper integral mirror is used to homogenize the laser energy distribution (uniformity ≥ 95%), combined with real-time monitoring by a pyrometer, accurately controlling the heating temperature of the surface of the high-strength steel plate to be composite (400-700 °C), reducing the surface microhardness through the dynamic tempering effect (reducing to 200-400 HV), forming a gradient softening layer, and reducing the hardness difference with the stainless steel plate to ≤ 30%. In the traditional process, the hardness difference between stainless steel and high-strength steel can reach more than 150 HV, resulting in stress concentration and easy cracking at the composite interface; in the present invention, through the cooperative treatment of dissimilar metals, the hardness difference is reduced to ≤ 30%, significantly improving the deformation coordination, and the interface bonding strength is increased by more than 20%.

[0008] Subsequently, online laser composite rolling is adopted: by adjusting the spatial angle (50 - 80°) between the high-strength steel plate and the stainless-steel plate, combined with the thermal effect of the auxiliary composite laser beam (power 1300 - 2500 W), during the rolling process (speed 0.5 - 2.8 mm / s, reduction ratio 33 - 60%), metal atom diffusion and metallurgical bonding are achieved, avoiding the risk of interface oxidation in traditional multi-pass rolling.

[0009] Finally, after the high-strength steel - stainless-steel composite plate processed by laser compounding passes through the guiding roller, it enters the roller press annealing device to simultaneously achieve the improvement of bonding strength, annealing, and leveling, which is completed online throughout the process, reducing 3 - 5 transfer processes in the traditional process.

[0010] Furthermore, in the step S2, when the tensile strength of the high-strength steel plate is 500 - 800 MPa, the width of the preheating light spot is set to 2 - 3 mm, the maximum surface heating temperature of the irradiated area of the preheating light spot is 400 - 550 °C, and the microhardness of the surface to be compounded of the high-strength steel plate after treatment is reduced to 200 - 290 HV.

[0011] Furthermore, the distance between the preheating light spot in the step S2 and the auxiliary composite processing laser light spot in the step S3 is 2 - 3 mm.

[0012] Furthermore, in the step S2, when the tensile strength of the high-strength steel plate is greater than 800 MPa, the width of the preheating light spot is set to 3 - 5 mm, the maximum surface heating temperature of the irradiated area of the preheating light spot is 500 - 700 °C, and the microhardness of the surface to be compounded of the high-strength steel plate after treatment is reduced to 320 - 400 HV.

[0013] Furthermore, the distance between the preheating light spot in the step S2 and the auxiliary composite processing laser light spot in the step S3 is ≤ 1.5 mm.

[0014] The method in the present invention has strong universality and strong adaptability to high-strength steel. By adjusting the laser pretreatment parameters (light spot width 2 - 5 mm, temperature 400 - 700 °C), high-strength steels with a tensile strength of 500 - 1000 MPa (such as DP steel, martensitic steel, TRIP steel, etc.) can be adapted, and the microhardness regulation range covers 200 - 400 HV; the stainless steel has good compatibility and is suitable for austenitic stainless steels such as 304 / 316L and duplex stainless steels, and the strengthening effect and strengthening depth can be flexibly adjusted. The examples have verified the compounding of 1 - 3 mm thick stainless steel and 1.5 - 3 mm thick high-strength steel. By adjusting the roll gap and reduction ratio, it can be extended to the compounding of thick plates over 5 mm, and thin plates / thick plates are universal.

[0015] Furthermore, in the step S1, during the treatment process of the ultrasonic rolling device, the ultrasonic rolling static pressure is 200 - 400 N, the ultrasonic frequency is 20 - 40 kHz, and the ultrasonic amplitude is 5 - 7 μm.

[0016] After multiple tests and verifications, if the static pressure, frequency, and amplitude of ultrasonic rolling are too large, microcracks will appear on the surface of stainless steel, and the surface roughness will deteriorate. If the parameters are too small, the strengthening of the surface microhardness will be insufficient and the depth will not be enough. During the later composite process, the composite surface with high-strength steel cannot deform well in coordination.

[0017] In specific applications, if the strengthening depth of the surface of the stainless steel plate to be composite does not reach 150 μm, the number of ultrasonic rolling devices can be increased to 2 - 5 groups.

[0018] Furthermore, in the step S3, the laser beam for assisted composite processing is shaped by spot homogenization based on a microlens array, and the spot width is the same as the width of the composite material to be processed. The power of the laser beam for assisted composite processing is 1300 - 2500 W, the rolling composite speed is 0.5 - 2.8 mm / s, and the reduction ratio is 33 - 60%.

[0019] After multiple tests and verifications, the laser power and rolling speed jointly affect the heat input. If the heat input is too high, the steel will melt and adhere to the surface of the roll, affecting the composite processing. If the heat input is insufficient, rolling composite cannot be achieved with a small reduction ratio. If the reduction ratio is too high, the composite plate will deform severely, and if it is too small, the interfacial bonding strength will be insufficient.

[0020] Furthermore, in the step S4, the roll pressing and annealing device consists of a warm pressing mechanism and a thermal straightening mechanism.

[0021] Furthermore, the warm pressing mechanism consists of multiple sets of roll systems with a diameter of 160 - 200 mm and induction coils arranged inside the rolls. The surface temperature of the rolls is 230 - 400 °C, and the reduction ratio of each set of roll systems is 3 - 5%, so as to further improve the interfacial bonding strength through the synergistic effect of heat and force.

[0022] The thermal activation effect (interface temperature ≥ 500 °C) and mechanical pressure (reduction ratio of 3 - 5%) in the warm pressing stage act synergistically, increasing the interfacial atomic diffusion coefficient by 3 - 5 times, and a continuous solid solution structure is formed in the bonding zone.

[0023] Furthermore, the thermal straightening mechanism consists of an induction heating module, an air cooling device, and a leveling work roll. After the high-strength steel and stainless steel composite plate passes through the warm pressing mechanism, annealing treatment is first carried out using the induction heating module. The heating temperature for induction annealing treatment is 550 - 700 °C, and it is carried out in an atmosphere of argon and nitrogen. Then it enters the air cooling device for cooling treatment, and its temperature is lower than 150 °C. Finally, it enters the leveling work roll for leveling treatment to obtain a high-strength steel and stainless steel composite plate with a wave height ≤ 2 mm / m.

[0024] Compared with the prior art, the present invention has the following beneficial effects: (1) By nanostructuring the surface layer at the stainless steel interface to be compounded and softening the surface layer at the high-strength steel interface to be compounded, the difference in microhardness between the metals on both sides of the interface to be compounded is significantly reduced, that is, the deformation coordination of the two metals with large differences during the compounding process is improved, so as to achieve the metallurgical bonding between dissimilar metals with large strength differences.

[0025] (2) Adopt online laser compound rolling. By adjusting the spatial angle between the high-strength steel plate and the stainless steel plate and combining the thermal effect of the auxiliary compound laser beam, the diffusion of metal atoms and metallurgical bonding are realized during the rolling process, avoiding the risk of interface oxidation in traditional multi-pass rolling.

[0026] (3) Utilize the coordinated work of the warm pressing mechanism and the hot straightening mechanism to perform online roll pressing and annealing treatment on the high-strength steel stainless steel composite plate after laser compound processing. On the one hand, under the thermo-mechanical coupling effect, the diffusion ability of atoms near the bonding interface is enhanced, further improving the interface bonding strength of the composite plate; on the other hand, the online annealing and straightening treatment after composite processing reduces the process flow and realizes short process flow. Brief Description of the Drawings

[0027] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0028] Figure 1 It is a schematic diagram of the laser compound-roll pressing annealing operation process of the high-strength steel stainless steel composite plate in the present invention. Specific Embodiments

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a 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 shall fall within the protection scope of the present invention.

[0030] Example 1 A method for laser compound-roll pressing annealing of a high-strength steel stainless steel composite plate, as Figure 1 shown, includes the following steps: S1. Nanostructuring treatment of the stainless steel surface: Select a 1-mm-thick stainless steel strip, and use the ultrasonic rolling device arranged between the front tension roller and the limit roller group to perform surface strengthening treatment on the stainless steel surface to be compounded. The static pressure of ultrasonic rolling is 200 N, the ultrasonic frequency is 40 kHz, and the ultrasonic amplitude is 5 μm. The microhardness of the stainless steel plate surface to be compounded after treatment is 325 HV, and the treatment layer depth is 165 μm.

[0031] S2. Laser pretreatment of the high-strength steel surface: Select high-strength steel with a thickness of 2 mm and a tensile strength of 600 MPa. Based on the spot homogenization and shaping mechanism of the copper integral mirror, a preheating spot with a flat-top energy distribution and a width of 2 mm is obtained. Combined with the coaxial coupling of the pyrometer, the maximum surface heating temperature of the laser irradiation area is controlled at 450 °C. Use this preheating spot to achieve softening pretreatment of the surface of the high-strength steel to be bonded. After treatment, the microhardness of the surface of the high-strength steel plate to be composite decreases to 283 HV, and the microhardness test standard is GB / T4340.1—2024.

[0032] S3. Laser compounding: Use the upper and lower two limit roller groups to adjust the spatial angle between the high-strength steel and the stainless steel to 70°. Feed the surface-hardened stainless steel plate processed by the ultrasonic rolling device and the high-strength steel plate with surface softening pretreatment by laser irradiation into the composite rolling mill. Under the action of the auxiliary composite processing laser beam, layered compounding is achieved. The power of the auxiliary composite processing laser beam is 1300 W, the rolling compounding speed is 0.5 mm / s, and the reduction ratio is 40% to obtain a high-strength steel stainless steel composite plate.

[0033] S4. Online roller pressing and annealing: The high-strength steel stainless steel composite plate after laser compounding processing enters the roller pressing and annealing device. The roller pressing and annealing device consists of a temperature-pressure mechanism and a thermal straightening mechanism. The temperature-pressure mechanism consists of 3 sets of roll systems with a diameter of 180 mm and induction coils arranged inside the rolls, and the surface temperature of the rolling mill is 350 °C. The reduction ratio of each set of roll systems is 3% to further improve the interfacial bonding strength through the synergistic action of heat and force. The thermal straightening mechanism consists of an induction heating module, an air cooling device, and a leveling working roll. After the high-strength steel stainless steel composite plate passes through the temperature-pressure mechanism, annealing treatment is first carried out using the induction heating module. The heating temperature of the induction annealing treatment is 600 °C and is carried out in an argon and nitrogen atmosphere. Then it enters the air cooling device for cooling treatment, and its temperature is lower than 150 °C. Finally, it enters the leveling working roll for leveling treatment to obtain a high-strength steel stainless steel composite plate with an unevenness of 1.6 mm / m.

[0034] The thickness specification of the high-strength steel stainless steel composite plate prepared in this embodiment is 1.64 mm, and the interfacial shear strength is 192 MPa. The shear strength test standard is GB / T 6396-2008.

[0035] Example 2 A laser compounding-roller pressing and annealing method for a high-strength steel stainless steel composite plate, comprising the following steps: S1. Nanocrystallization treatment of the stainless steel surface: Select a 1-mm-thick stainless steel strip, and use an ultrasonic rolling device set between the front tension roller and the limit roller group to perform surface strengthening treatment on the surface of the stainless steel to be compounded. The static pressure of ultrasonic rolling is 300 N, the ultrasonic frequency is 20 kHz, and the ultrasonic amplitude is 5 μm. After treatment, the microhardness of the surface of the stainless steel plate to be compounded is 330 HV, and the depth of the treated layer is 160 μm.

[0036] S2. Laser pretreatment of the high-strength steel surface: Select a 1.5-mm-thick high-strength steel with a tensile strength of 800 MPa. Based on the spot homogenization and shaping mechanism of the copper integral mirror, obtain a preheating spot with a flat-top energy distribution with a width of 3 mm. Combine the coaxial coupling of the pyrometer to control the maximum surface heating temperature of the laser irradiation area to be 550 °C. Use this preheating spot to achieve softening pretreatment of the surface of the high-strength steel to be bonded. After treatment, the microhardness of the surface of the high-strength steel plate to be compounded drops to 291 HV.

[0037] S3. Laser compounding: Use the upper and lower limit roller groups to adjust the space angle between the high-strength steel and the stainless steel to be 70°. Feed the surface-hardened stainless steel plate processed by the ultrasonic rolling device and the high-strength steel plate with surface-softening pretreatment by laser irradiation into the composite rolling mill, and achieve layered compounding under the action of the auxiliary composite processing laser beam. The power of the auxiliary composite processing laser beam is 2000 W, the rolling composite speed is 1.5 mm / s, and the reduction ratio is 33% to obtain a high-strength steel-stainless steel composite plate.

[0038] S4. Online roller pressing and annealing: The high-strength steel-stainless steel composite plate after laser compounding enters the roller pressing and annealing device. The roller pressing and annealing device consists of a temperature-pressure mechanism and a thermal straightening mechanism. The temperature-pressure mechanism consists of 3 sets of roller systems with a diameter of 180 mm and induction coils arranged inside the rollers. The surface temperature of the rolling mill is 400 °C, and the reduction ratio of each set of roller systems is 3% to further improve the interfacial bonding strength through the synergistic effect of heat and force. The thermal straightening mechanism consists of an induction heating module, an air cooling device, and a leveling working roller. After the high-strength steel-stainless steel composite plate passes through the temperature-pressure mechanism, first use the induction heating module to perform annealing treatment. The heating temperature of the induction annealing treatment is 600 °C, and it is carried out in an argon and nitrogen atmosphere. Then enter the air cooling device for cooling treatment, and its temperature is lower than 150 °C. Finally, enter the leveling working roller for leveling treatment to obtain a high-strength steel-stainless steel composite plate with an unevenness of 1.5 mm / m.

[0039] The high-strength steel-stainless steel composite plate prepared in this embodiment has a thickness specification of 1.51 mm and an interfacial shear strength of 197 MPa.

[0040] Example 3 A laser compounding-roll pressing annealing method for high-strength steel and stainless steel composite plates, comprising the following steps: S1. Nanocrystallization treatment of the stainless steel surface: Select a 2-mm-thick stainless steel strip, and use an ultrasonic rolling device arranged between the front tension roller and the limit roller group to perform surface strengthening treatment on the surface of the stainless steel to be compounded. The static pressure of ultrasonic rolling is 400 N, the ultrasonic frequency is 20 kHz, the ultrasonic amplitude is 7 μm. After treatment, the microhardness of the surface of the stainless steel plate to be compounded is 332 HV, and the depth of the treated layer is 180 μm.

[0041] S2. Laser pretreatment of the high-strength steel surface: Select a 3-mm-thick high-strength steel with a tensile strength of 1000 MPa. Based on the spot homogenization and shaping mechanism of the copper integral mirror, obtain a preheating spot with a flat-top energy distribution and a width of 5 mm. Combined with the coaxial coupling of the pyrometer, control the maximum surface heating temperature of the laser irradiation area to be 700 °C, and use this preheating spot to realize the softening pretreatment of the surface of the high-strength steel to be joined. After treatment, the microhardness of the surface of the high-strength steel plate to be compounded is reduced to 323 HV.

[0042] S3. Laser compounding: Using the upper and lower limit roller groups, adjust the spatial angle between the high-strength steel and the stainless steel to be 70°. Feed the surface-hardened stainless steel plate treated by the ultrasonic rolling device and the high-strength steel plate with the surface softened by laser irradiation into the compound rolling mill, and realize layered compounding under the action of the auxiliary compounding processing laser beam. The power of the auxiliary compounding processing laser beam is 2500 W, the rolling compounding speed is 2.8 mm / s, and the reduction ratio is 60% to obtain a high-strength steel and stainless steel composite plate.

[0043] S4. Online roll pressing annealing: The high-strength steel and stainless steel composite plate after laser compounding processing enters the roll pressing annealing device. The roll pressing annealing device consists of a temperature and pressure mechanism and a thermal straightening mechanism. The temperature and pressure mechanism consists of 3 sets of roll systems with a diameter of 180 mm and induction coils arranged inside the rolls, and the surface temperature of the rolling mill is 400 °C. The reduction ratio of each set of roll systems is 5% to further improve the interface bonding strength through the synergistic effect of heat and force. The thermal straightening mechanism consists of an induction heating module, an air cooling device, and a leveling work roll. After the high-strength steel and stainless steel composite plate passes through the temperature and pressure mechanism, first use the induction heating module to perform annealing treatment. The heating temperature of the induction annealing treatment is 600 °C, and it is carried out in an argon and nitrogen atmosphere, and then enter the air cooling device for cooling treatment, and its temperature is lower than 150 °C. Finally, enter the leveling work roll for leveling treatment to obtain a high-strength steel and stainless steel composite plate with an unevenness of 1.8 mm / m.

[0044] The thickness specification of the high-strength steel and stainless steel composite plate prepared in this embodiment is 1.72 mm, and the interface shear strength is 208 MPa.

[0045] Comparative Example 1 Comparative Example 1 is a comparative test example of Example 1. The surface of the stainless steel was not subjected to nanometer treatment, and other implementation steps and specific parameters were the same as those of Example 1.

[0046] The thickness specification of the high-strength steel stainless steel composite plate prepared in this comparative example is 1.64 mm, and the interfacial shear strength is 103 MPa.

[0047] Comparative Example 2 Comparative Example 2 is a comparative test example of Example 1. The surface of the high-strength steel was not subjected to laser softening pretreatment, and other implementation steps and specific parameters were the same as those of Example 1.

[0048] The thickness specification of the high-strength steel stainless steel composite plate prepared in this comparative example is 1.66 mm, and the interfacial shear strength is 121 MPa.

[0049] Comparative Example 3 Comparative Example 3 is a comparative test example of Example 1. The surface of the stainless steel was not subjected to nanometer treatment, and at the same time, the surface of the high-strength steel was not subjected to laser softening pretreatment. Other implementation steps and specific parameters were the same as those of Example 1.

[0050] The bonding effect of the high-strength steel stainless steel composite plate prepared in this comparative example is not good.

[0051] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A laser compound-roll pressing annealing method for high-strength steel and stainless steel composite plates, characterized in that, It includes the following steps: S1. Nanocrystallization treatment of the stainless steel surface: The surface to be compounded of the stainless steel plate is strengthened by an ultrasonic rolling device. After treatment, the microhardness of the surface to be compounded of the stainless steel plate is 220 - 380 HV, and the depth of the treatment layer is 150 - 200 μm; S2. Laser pretreatment of the high-strength steel surface: A preheating spot with a flat-top energy distribution is obtained by using a copper integral mirror to homogenize the energy distribution of the light spot, combined with temperature control by a pyrometer. The surface to be compounded of the high-strength steel plate is softened by pretreatment. After treatment, the microhardness of the surface to be compounded of the high-strength steel plate is reduced to 200 - 400 HV; S3. Laser compounding: The surface-hardened stainless steel plate treated by the ultrasonic rolling device and the high-strength steel plate with surface softening pretreatment by laser irradiation are fed into a compound rolling mill, and layered compounding is realized under the action of an auxiliary compounding processing laser beam to obtain a high-strength steel - stainless steel composite plate; S4. Online roll pressing and annealing: The high-strength steel - stainless steel composite plate after laser compounding processing enters a roll pressing and annealing device to simultaneously improve the bonding strength, anneal, and flatten the composite plate.

2. The laser compound-roll pressing annealing method for the high-strength steel stainless steel composite plate according to claim 1, wherein, In step S2, when the tensile strength of the high-strength steel plate is 500 - 800 MPa, the width of the preheating spot is set to 2 - 3 mm, the maximum surface heating temperature of the irradiated area of the preheating spot is 400 - 550 °C, and after treatment, the microhardness of the surface to be compounded of the high-strength steel plate is reduced to 200 - 290 HV.

3. The laser compound-roll pressing annealing method for the high-strength steel stainless steel composite plate according to claim 2, wherein The distance between the preheating spot in step S2 and the auxiliary compounding processing laser spot in step S3 is 2 - 3 mm.

4. The laser composite-roll pressing annealing method for high-strength steel and stainless steel composite plate according to claim 1, wherein In step S2, when the tensile strength of the high-strength steel plate is greater than 800 MPa, the width of the preheating spot is set to 3 - 5 mm, the maximum surface heating temperature of the irradiated area of the preheating spot is 500 - 700 °C, and after treatment, the microhardness of the surface to be compounded of the high-strength steel plate is reduced to 320 - 400 HV.

5. The laser composite-roll pressing annealing method for high-strength steel and stainless steel composite plates according to claim 4, characterized in that, The distance between the preheating spot in step S2 and the auxiliary compounding processing laser spot in step S3 is ≤ 1.5 mm.

6. The laser compound-roll pressing annealing method for the high-strength steel and stainless steel composite plate according to claim 1, characterized in that In step S1, during the treatment process of the ultrasonic rolling device, the ultrasonic rolling static pressure is 200 - 400 N, the ultrasonic frequency is 20 - 40 kHz, and the ultrasonic amplitude is 5 - 7 μm.

7. The laser composite-roll pressing annealing method for high-strength steel and stainless steel composite plate according to claim 1, wherein In step S3, the power of the auxiliary compounding processing laser beam is 1300 - 2500 W, the rolling compounding speed is 0.5 - 2.8 mm / s, and the reduction ratio is 33 - 60%.

8. The laser composite-roll pressing annealing method for high-strength steel and stainless steel composite plates according to claim 1, characterized in that, In step S4, the roll pressing and annealing device consists of a temperature and pressure mechanism and a thermal straightening mechanism.

9. The laser compound-roll pressing annealing method for high-strength steel and stainless steel composite plates according to claim 8, wherein, The temperature and pressure mechanism consists of a series of rolls with a diameter of 160 - 200 mm and induction coils arranged inside the rolls. The surface temperature of the rolling mill rolls is 230 - 400 °C, and the reduction ratio of each series of rolls is 3 - 5%.

10. The laser composite-roll pressing annealing method for the high-strength steel and stainless steel composite plate according to claim 9, characterized in that, The thermal straightening mechanism consists of an induction heating module, an air cooling device, and straightening working rolls. After the high-strength steel - stainless steel composite plate passes through the temperature and pressure mechanism, annealing treatment is first carried out by using the induction heating module, then it enters the air cooling device for cooling treatment, and finally enters the straightening working rolls for straightening treatment.

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