Processing method of high-toughness stainless steel / carbon steel composite plate

Abstract

The invention discloses a processing method of a high-toughness stainless steel / carbon steel composite plate, which comprises the following steps: compounding a high-strength carbon steel plate and a stainless steel plate through a rolling compounding process under the action of laser-assisted heating; then, the stainless steel / carbon steel composite sheet is subjected to temperature control type online periodic laser surface annealing treatment, so that a corrosion-resistant structure with a non-uniform structure in which coarse grains (a soft region) and fine grains (a hard region) are alternately arranged can be obtained on the stainless steel surface layer, and the corrosion resistance of the composite plate is improved; and meanwhile, the stress relief effect induced by laser surface annealing treatment is combined with high-temperature tempering softening of a martensitic structure on the carbon steel side part at the interface, and a heterogeneous structure induced by laser surface annealing treatment can synchronously improve the obdurability of the stainless steel / carbon steel composite plate.

Description

Technical Field

[0001] The invention relates to the technical field of stainless steel composite plate processing, and in particular to a processing method of a high-strength and tough stainless steel / carbon steel composite plate. Background Art

[0002] Heterogeneous metal composite materials effectively bring into play the performance advantages of each component metal, while significantly reducing material costs, and have broad application prospects. For example, stainless steel / carbon steel composite plates are based on carbon steel and stainless steel as the cladding, and are metallurgically bonded by rolling composite, explosive composite and other methods. They are widely used in nuclear power, hydropower, pressure vessels, petrochemical and other industries.

[0003] To this end, the invention patent with application number CN201410823984.3 proposes a rolling method for pipeline steel and stainless steel composite plates. This method prepares a stainless steel / carbon steel composite plate with high strength by regulating heating, rolling, controlled cooling and other processes. The tensile strength of the stainless steel / carbon steel composite plate prepared by this method is 590MPa. The invention patent with application number CN202410752115.X proposes a production method for stainless steel-bridge steel composite plates. This method prepares stainless steel / carbon steel composite plates through processes such as surface treatment of raw material slabs, assembly of composite slabs, segmented heating, rough rolling of composite slabs, finishing rolling, cooling after rolling and annealing heat treatment of composite plates after rolling. However, similarly, because the strength of the base material (Q345) is low and it undergoes multiple high-temperature annealing, the strength of the stainless steel / carbon steel composite plate prepared by this process is still not high, only 545MPa. It can be found that the stainless steel / carbon steel composite plates produced by the existing process generally have the problem of low strength and cannot meet the demand for high-strength stainless steel / carbon steel composite plates in specific industrial environments. How to improve the strength of stainless steel / carbon steel composite plates while maintaining excellent toughness and achieving a short process is an urgent problem to be solved.

[0004] Therefore, this patent proposes a method for processing high-strength and toughness stainless steel / carbon steel composite plates, which utilizes a one-step forming and rolling composite process under laser-assisted heating + online periodic laser surface annealing treatment to achieve simultaneous improvement of strength, toughness and corrosion resistance, so as to meet the current industrial field's urgent demand for high-strength and toughness stainless steel / carbon steel composite plates. Summary of the invention

[0005] In order to solve the problems existing in the above-mentioned background technology, the present invention provides a processing method of high-strength and toughness stainless steel / carbon steel composite plate, which utilizes the synergistic effect of laser-induced thermal effect and rolling force to achieve the lamination of stainless steel and high-strength carbon steel, and then utilizes periodic laser surface annealing technology to simultaneously achieve surface tissue isomerization, improve corrosion resistance and reduce residual stress.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for processing a high-strength and tough stainless steel / carbon steel composite plate, comprising the following steps: S1. Machining and surface treatment: The high-strength carbon steel plate and the stainless steel plate are processed into plates of the same width, and then the surfaces to be composited of the high-strength carbon steel plate and the stainless steel plate are polished to perform surface roughening treatment. After the treatment is completed, the surfaces to be composited are cleaned to remove surface stains; S2, Laser-assisted rolling composite: The high-strength carbon steel plate and the stainless steel plate are stacked relative to each other and aligned on all sides for combination. One end of the combined plate is sent to the rolling mill for cold rolling and pressing. The rolling mill is pressed down to bite the two plates together. The unpressed parts of the two plates are opened to form an opening. The laser processing head outputs a flat-top line spot and irradiates the laser from the opening to the bonding interface of the two plates. Subsequently, the rolling mill is started, and the laser processing head emits light to heat the interface to be composited between the stainless steel plate and the high-strength carbon steel plate. Under the action of the rolling force, the two metals are metallurgically bonded at the interface, and the stainless steel plate and the high-strength carbon steel plate are composited into one to form a stainless steel / carbon steel composite plate. S3, periodic laser surface annealing: The stainless steel surface of the stainless steel / carbon steel composite plate is subjected to temperature-controlled, periodic laser surface annealing treatment using a homogenized light spot, and a non-uniform structure of alternating coarse-fine grains is constructed in the stainless steel surface area.

[0007] Using the above technical solution: In the present invention, the high-strength carbon steel plate and the stainless steel plate are composited by utilizing the synergistic effect of laser-induced thermal effect and rolling force; then the stainless steel / carbon steel composite plate is subjected to temperature-controlled, periodic laser surface annealing, and on the basis of achieving metallurgical surface bonding of heterogeneous metals, a corrosion-resistant, high-strength and tough structure with alternating soft and hard zones is constructed, which significantly improves the service performance of the stainless steel / carbon steel composite plate. At the same time, the periodic laser surface annealing treatment is carried out directly after the composite process. This online post-processing method greatly improves the processing efficiency and reduces the difficulty of winding the composite material.

[0008] Furthermore, in step S2, the angle of the opening formed by the two plates not pressed together is 40 to 80 degrees.

[0009] Specifically, in step S2, the unpressed portion of the two plates (high-strength carbon steel plate and stainless steel plate) is opened to form an opening at a certain angle, so that the laser can be irradiated on the interface to be composited between the high-strength carbon steel plate and the stainless steel plate. Since the laser energy will be reflected when irradiating a material with a certain reflectivity, the angle of the opening is different, the number of times the laser is reflected is different, and the energy finally concentrated at the bonding interface is also different. After many experiments, it is preferably controlled that the angle of the opening formed by the unpressed portion of the two plates is controlled to be 40 to 80°, and more preferably, the angle of the opening formed is controlled to be 60°.

[0010] Furthermore, in step S2, the length of the line light spot is consistent with the width of the plate, the width of the line light spot is 0.7 to 2 times the sum of the thicknesses of the two plates, and the angle between the line light spot and the horizontal direction is 0 to 17 degrees.

[0011] When working, the laser turns on the red indicator light, so that the laser line spot passes through the opening and irradiates the bonding interface of the two plates. In order to irradiate the entire interface to be composited, the length of the line spot is the same as the width of the material bonding interface; at the same time, in order to ensure the coordination of the deformation of dissimilar metals in the micro-area of ​​the bonding interface, the width of the line spot is 0.7 to 2 times the sum of the thickness of the two plates.

[0012] When the thickness of the high-strength carbon steel plate is ≤3.5mm and the tensile strength of the high-strength carbon steel plate is ≤800MPa, the area ratio of the laser irradiation area of ​​the high-strength carbon steel plate and the stainless steel plate is approximately equal to the strength ratio of the two, and the maximum heating temperature of the laser-induced bonding interface is lower than the solidus. If the thickness of the high-strength carbon steel plate exceeds 3.5mm, regardless of whether its strength exceeds 800MPa, the laser power will be increased and the laser irradiation area of ​​the high-strength carbon steel plate will be increased (the area ratio of the laser irradiation area of ​​the stainless steel plate / high-strength carbon steel plate is 0.7~0.4), so that the maximum heating temperature of the high-strength carbon steel plate at the bonding position reaches above the melting point. If the tensile strength of the high-strength carbon steel plate exceeds 800MPa, but the thickness is ≤3.5mm, the rolling force will be increased to ensure that the maximum heating temperature of the bonding interface is lower than the melting point.

[0013] Furthermore, in step S2, the rolling rate of the rolling mill is 0.5 to 3 m / min, and the rolling reduction ratio is 25 to 60%.

[0014] Because the rolling of stainless steel plates and high-strength carbon steel plates requires high pressure and high temperature to achieve composite, the laser provides heat, the rolling mill provides a large rolling force, the rolling speed is slow, and the laser heat input can continuously heat the interface to be composited, and the composite effect is good. After many tests and verifications, in order to ensure both processing efficiency and composite effect, the rolling reduction rate is controlled to 25-60%, and the rolling rate of the rolling mill is controlled to 0.5-3m / min.

[0015] Furthermore, in step S3, the length of the homogenized spot is consistent with the width of the stainless steel / carbon steel composite plate, high-power laser and low-power laser are alternately irradiated to the stainless steel surface, and a pyrometer is used to monitor the heating temperature of the laser surface annealing area in real time.

[0016] Specifically, the maximum heating temperature of the high-power laser irradiation area is controlled at 850-1100° C., and the maximum heating temperature of the low-power laser irradiation area is controlled at 500-680° C. The width of a single high-power laser irradiation area or a low-power laser irradiation area is 0.5-2 mm.

[0017] The stainless steel / carbon steel composite plate is subjected to periodic laser surface annealing treatment using a homogenized spot to synergistically improve its strength, toughness and corrosion resistance. Specifically, the stainless steel surface is irradiated periodically with a temperature-controlled homogenized spot whose spot length is consistent with the width of the stainless steel / carbon steel composite plate. The temperature control type is to use a pyrometer to monitor the heating temperature of the laser surface annealing area in real time, and to control the heating temperature of the laser irradiation area through closed-loop regulation of the laser power; periodicity refers to the alternation of high-power laser irradiation and low-power laser irradiation, that is, high-power laser irradiation causes the surface grains of stainless steel to coarsen, high-temperature tempering of the martensite structure on the carbon steel side near the bonding interface, and only stress relief annealing of the carbon steel plate away from the bonding interface, and low-power laser irradiation only induces stress relief in the surface area of ​​stainless steel, thereby constructing a non-uniform structure of alternating coarse grains (soft area) and fine grains (hard area) in the surface area of ​​stainless steel, and utilizing the interaction between the soft area and the hard area to further improve the corrosion resistance of stainless steel. At the same time, combined with the high-temperature tempering softening of part of the martensitic structure on the carbon steel plate side at the interface, combined with the mutation-induced strengthening and work hardening effects, the strength and toughness of the stainless steel / high-strength carbon steel plate composite plate are improved.

[0018] Furthermore, the material of the high-strength carbon steel plate is low alloy steel with a tensile strength ≥ 600MPa, such as: Q690 steel, Q890 steel, Q960 steel, etc.

[0019] Furthermore, in step S1, after sandpaper grinding, wire brush grinding or belt wheel grinding, the roughness Ra of the surface to be composited of the high-strength carbon steel plate and the stainless steel plate is 3.2 to 6.3 μm. Mechanical grinding increases the surface roughness of the material so that the mechanical locking is increased when the stainless steel and carbon steel surfaces are in contact, thereby improving the subsequent laser rolling composite effect. After grinding, the stainless steel and carbon steel need to use a dust adsorption system to remove particles remaining on the surface.

[0020] Compared with the prior art, the present invention has the following beneficial effects: In the present invention, the high-strength carbon steel plate and the stainless steel plate are composited by utilizing the synergistic effect of laser-induced thermal effect and rolling force; then the stainless steel / carbon steel composite plate is subjected to temperature-controlled, periodic laser surface annealing, and on the basis of achieving metallurgical surface bonding of heterogeneous metals, a corrosion-resistant, high-strength and tough structure with alternating soft and hard zones is constructed, which significantly improves the service performance of the stainless steel / carbon steel composite plate. At the same time, the periodic laser surface annealing treatment is carried out directly after the composite process. This online post-processing method greatly improves the processing efficiency and reduces the difficulty of winding the composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Figure 1 This is a microstructure distribution diagram of the stainless steel / carbon steel composite plate after periodic laser surface annealing in the present invention.

[0023] The specific figures are: High power laser irradiation area 1, low power laser irradiation area 2, coarse grain area 11, tempered martensite 12, fine grain area 21. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The present invention discloses a method for processing a high-strength and tough stainless steel / carbon steel composite plate, comprising the following steps: S1. Machining and surface treatment: High-strength carbon steel plates and stainless steel plates are processed into plates of the same width. Stainless steel and carbon steel of the same width are single-sided polished by sandpaper grinding, wire brush polishing, belt wheel polishing, etc. to obtain a surface to be bonded with a surface roughness Ra of 3.2 to 6.3 μm. Mechanical polishing increases the surface roughness of the material so that the mechanical locking is increased when the stainless steel and carbon steel surfaces are in contact, thereby improving the subsequent laser rolling composite effect. After polishing, the stainless steel and carbon steel need to use a dust adsorption system to remove particles remaining on the surface.

[0026] The material of high-strength carbon steel plate is low-alloy steel with a tensile strength ≥600MPa, such as: Q690 steel, Q890 steel, Q960 steel, etc.

[0027] S2, Laser-assisted rolling composite: The high-strength carbon steel plate and the stainless steel plate are stacked relative to each other and aligned on all sides for combination. One end of the combined plate is sent to the rolling mill for cold rolling and pressing. The rolling mill is pressed down to bite the two plates together, and the unpressed parts of the two plates are opened to form an opening. The laser processing head outputs a flat-top line spot and irradiates the laser from the opening to the bonding interface of the two plates. Subsequently, the rolling mill is started, and the laser processing head emits light to heat the interface to be composited between the stainless steel plate and the high-strength carbon steel plate. Under the action of the rolling force, the two metals are metallurgically bonded at the interface, and the stainless steel plate and the high-strength carbon steel plate are composited into one to form a stainless steel / carbon steel composite plate.

[0028] The angle of the opening formed by the unpressed parts of the two plates is 40 to 80 degrees, and the line spot is directly irradiated on the surfaces of the two metals to be combined in the form of an angle of 0 to 17 degrees with the horizontal direction.

[0029] When the thickness of the high-strength carbon steel plate is ≤3.5mm and the tensile strength of the high-strength carbon steel plate is ≤800MPa, the area ratio of the laser irradiation area of ​​the high-strength carbon steel plate and the stainless steel plate is approximately equal to the strength ratio of the two, and the maximum heating temperature of the laser-induced bonding interface is lower than the solidus. If the thickness of the high-strength carbon steel plate exceeds 3.5mm, regardless of whether its strength exceeds 800MPa, the laser power will be increased and the laser irradiation area of ​​the high-strength carbon steel plate will be increased (the area ratio of the laser irradiation area of ​​the stainless steel plate / high-strength carbon steel plate is 0.7~0.4), so that the maximum heating temperature of the high-strength carbon steel plate at the bonding position reaches above the melting point. If the tensile strength of the high-strength carbon steel plate exceeds 800MPa, but the thickness is ≤3.5mm, the rolling force will be increased to ensure that the maximum heating temperature of the bonding interface is lower than the melting point.

[0030] The length of the line spot is consistent with the width of the plate, and the width of the line spot is 0.7 to 2 times the sum of the thickness of the two plates.

[0031] The rolling rate of the rolling mill is 0.5 to 3 m / min, and the rolling reduction rate is 25 to 60%.

[0032] S3, periodic laser surface annealing: The stainless steel / carbon steel composite plate is subjected to periodic laser surface annealing treatment using a homogenized spot to synergistically improve its strength, toughness and corrosion resistance. Specifically, the stainless steel surface is irradiated periodically with a temperature-controlled homogenized spot whose spot length is consistent with the width of the stainless steel / carbon steel composite plate. The temperature control type is to use a pyrometer to monitor the heating temperature of the laser surface annealing area in real time, and to control the heating temperature of the laser irradiation area through closed-loop regulation of the laser power; periodicity refers to the alternation of high-power laser irradiation and low-power laser irradiation, that is, high-power laser irradiation causes the surface grains of stainless steel to coarsen, high-temperature tempering of the martensite structure on the carbon steel side near the bonding interface, and only stress relief annealing of the carbon steel away from the bonding interface, and low-power laser irradiation only induces stress relief in the surface area of ​​stainless steel, thereby constructing a non-uniform structure of alternating coarse grains (soft area) and fine grains (hard area) in the surface area of ​​stainless steel, and utilizing the interaction between the soft area and the hard area to further improve the corrosion resistance of stainless steel. At the same time, combined with the high-temperature tempering softening of part of the martensite structure on the carbon steel side of the interface, combined with the mutation-induced strengthening and work hardening effects, the strength and toughness of the stainless steel / carbon steel composite plate are improved.

[0033] Specifically, Figure 1 As shown, the stainless steel surface is subjected to temperature-controlled periodic irradiation using a homogenized spot with a spot length consistent with the width of the stainless steel / carbon steel composite plate. The irradiation area on the stainless steel side is alternating between high-power laser irradiation area 1 and low-power laser irradiation area 2, and the width of a single high-power laser irradiation area 1 or low-power laser irradiation area 2 is 0.5-2 mm. The maximum heating temperature of the high-power laser irradiation area 1 is controlled at 850-1100°C, and the maximum heating temperature of the low-power laser irradiation area 2 is controlled at 500-680°C. The grain size of the stainless steel surface changes periodically, and a coarse grain area 11-fine grain area 21-coarse grain area 11-fine grain area 21 organization is obtained on the stainless steel surface, thereby constructing a non-uniform structure of alternating coarse grains (soft area)-fine grains (hard area) in the stainless steel surface area, and the interaction between the soft area and the hard area is used to further improve the corrosion resistance of the stainless steel. At the same time, in the high-power irradiation area, the martensite structure on the carbon steel side near the stainless steel / carbon steel bonding interface undergoes high-temperature tempering to become tempered martensite 12, and the carbon steel far away from the bonding interface only undergoes stress relief annealing to eliminate the stress generated during the processing.

[0034] Example 1 A method for processing a high-strength and tough stainless steel / carbon steel composite plate comprises the following steps: S1. Roughening treatment of the surface to be bonded: The Q690 high-strength carbon steel plate (tensile strength 813MPa) and the 304 stainless steel plate were ground with sandpaper, and the stainless steel and carbon steel with the same width were single-sided polished to obtain a surface to be combined with a surface roughness Ra of 3.3μm, and the dust adsorption system was used to remove the particles remaining on the surface.

[0035] S2, Laser-assisted rolling composite: Stainless steel and Q690 high-strength carbon steel bite into the rollers at a spatial angle of 60°, and the laser beam is directly irradiated on the surfaces of the two metals to be combined at an angle of 8° to the horizontal direction. The tensile strength of Q690 high-strength steel is 813MPa, the thickness specification is 1.5mm, the rolling reduction rate is 50%, and the maximum heating temperature of the bonding interface is 1200℃. At the same time, the laser beam spot width is 1.5 times the total thickness of the billet, and the laser beam spot length is consistent with the billet width. The stainless steel / carbon steel laser irradiation area ratio is 0.6; the rolling composite speed is 3m / min. Under the coupling effect of rolling force and laser, the two materials achieve metallurgical bonding at the interface, and the 304 stainless steel plate and the Q690 high-strength carbon steel plate are combined into a stainless steel / carbon steel composite plate.

[0036] S3, periodic laser surface annealing: The stainless steel / carbon steel composite plate was subjected to periodic laser surface annealing treatment using a homogenized spot. The maximum heating temperature of the high-power laser irradiation area was controlled at 1000°C, and the maximum heating temperature of the low-power laser irradiation area was controlled at 620°C. The width of the high-power laser irradiation area and the low-power laser irradiation area was 1.5 mm.

[0037] Finally, a stainless steel / carbon steel composite plate with a tensile strength of 934 MPa, an elongation after fracture of 21%, and a corrosion rate of 0.08 mm / a (completely corrosion resistant) was obtained.

[0038] The tensile strength test method is: according to "GB / T 228-2002 Metal Material Room Temperature Tensile Test Method", a tensile test is performed on the stainless steel / carbon steel composite sheet prepared by the present invention on a universal material testing machine to measure its tensile strength.

[0039] The corrosion rate test method is: according to "GB / T 4334-2020 Corrosion of Metals and Alloys - Test Method for Intergranular Corrosion of Austenite and Ferrite Austenite (Duplex) Stainless Steel", the stainless steel / carbon steel composite plate is placed in a 50wt% sulfuric acid-ferric sulfate solution and subjected to a boiling test, and the corrosion resistance is evaluated by the corrosion rate.

[0040] Example 2 A method for processing a high-strength and tough stainless steel / carbon steel composite plate comprises the following steps: S1. Roughening treatment of the surface to be bonded: The Q960 high-strength carbon steel plate (tensile strength 1066MPa) and the 304 stainless steel plate were polished with abrasive belt wheels, and the stainless steel and carbon steel with the same width were polished on one side to obtain a surface roughness Ra of 6.3μm for the surface to be combined, and the dust adsorption system was used to remove the particles remaining on the surface.

[0041] S2, Laser-assisted rolling composite: Stainless steel and Q960 high-strength carbon steel bite into the rollers at a spatial angle of 40°, and the laser beam is directly irradiated on the surfaces of the two metals to be combined at a 0° angle to the horizontal direction. The tensile strength of Q960 high-strength carbon steel is 1066MPa, the thickness specification is 1.5mm, the rolling reduction rate is 60%, and the maximum heating temperature of the bonding interface is 1300℃. At the same time, the laser beam spot width is twice the total thickness of the billet, and the laser beam spot length is consistent with the billet width. The stainless steel / carbon steel laser irradiation area ratio is 0.4; the rolling composite speed is 0.5m / min. Under the coupling effect of rolling force and laser heat, the two materials achieve metallurgical bonding at the interface, and the 304 stainless steel plate and the Q960 high-strength carbon steel plate are combined into a stainless steel / carbon steel composite plate.

[0042] S3, periodic laser surface annealing: The stainless steel / carbon steel composite plate was subjected to periodic laser surface annealing treatment using a homogenized spot. The maximum heating temperature of the high-power laser irradiation area was controlled at 1100°C, and the maximum heating temperature of the low-power laser irradiation area was controlled at 680°C. The width of the high-power laser irradiation area and the low-power laser irradiation area was 2 mm.

[0043] Finally, a stainless steel / carbon steel composite plate with a tensile strength of 1197 MPa, an elongation after fracture of 14%, and a corrosion rate of 0.091 mm / a (completely corrosion resistant) was obtained.

[0044] Example 3 A method for processing a high-strength and tough stainless steel / carbon steel composite plate comprises the following steps: S1. Roughening treatment of the surface to be bonded: Q890 high-strength carbon steel plate (tensile strength 994MPa) and 316 stainless steel plate were polished with a wire brush, and stainless steel and carbon steel of the same width were polished on one side to obtain a surface roughness Ra of 4.7μm for the surface to be combined, and the dust adsorption system was used to remove the particles remaining on the surface.

[0045] S2, Laser-assisted rolling composite: Stainless steel and Q890 high-strength carbon steel bite into the rollers at a spatial angle of 80°, and the laser beam is directly irradiated on the surfaces of the two metals to be combined at a 0° angle to the horizontal direction. The tensile strength of Q890 high-strength carbon steel is 994MPa, the thickness specification is 4mm, the rolling reduction rate is 40%, and the maximum heating temperature of the bonding interface is about 1200℃. At the same time, the spot width is 0.7 times the total thickness of the billet, and the spot length is consistent with the billet width. The area ratio of the stainless steel / carbon steel laser irradiation area is 0.7; the rolling composite speed is 1m / min. Under the coupling effect of rolling force and laser, the two materials achieve metallurgical bonding at the interface, and the 316 stainless steel plate and the Q890 high-strength carbon steel plate are composited into a stainless steel / carbon steel composite plate.

[0046] S3, periodic laser surface annealing: The stainless steel / carbon steel composite plate was subjected to periodic laser surface annealing treatment using a homogenized spot. The maximum heating temperature of the high-power laser irradiation area was controlled at 850°C, and the maximum heating temperature of the low-power laser irradiation area was controlled at 500°C. The width of the high-power laser irradiation area and the low-power laser irradiation area was 0.5 mm.

[0047] Finally, a stainless steel / carbon steel composite plate with a tensile strength of 1103 MPa, an elongation after fracture of 17%, and a corrosion rate of 0.088 mm / a (completely corrosion resistant) was obtained.

[0048] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for processing a high-strength and tough stainless steel / carbon steel composite plate, characterized in that: The following steps are involved: S1. Machining and surface treatment: The high-strength carbon steel plate and the stainless steel plate are processed into plates of the same width, and then the surfaces to be composited of the high-strength carbon steel plate and the stainless steel plate are polished to perform surface roughening treatment. After the treatment is completed, the surfaces to be composited are cleaned to remove surface stains; S2, Laser-assisted rolling composite: The high-strength carbon steel plate and the stainless steel plate are stacked relative to each other and aligned on all sides for combination. One end of the combined plate is sent to the rolling mill for cold rolling and pressing. The rolling mill is pressed down to bite the two plates together. The unpressed parts of the two plates are opened to form an opening. The laser processing head outputs a flat-top line spot and irradiates the laser from the opening to the bonding interface of the two plates. Subsequently, the rolling mill is started, and the laser processing head emits light to heat the interface to be composited between the stainless steel plate and the high-strength carbon steel plate. Under the action of the rolling force, the two metals are metallurgically bonded at the interface, and the stainless steel plate and the high-strength carbon steel plate are composited into one to form a stainless steel / carbon steel composite plate. S3, periodic laser surface annealing: The stainless steel surface of the stainless steel / carbon steel composite plate is subjected to temperature-controlled, periodic laser surface annealing treatment using a homogenized light spot, and a non-uniform structure of alternating coarse-fine grains is constructed in the stainless steel surface area.

2. The method for processing a high-strength and tough stainless steel / carbon steel composite plate according to claim 1, characterized in that: In step S2, the angle of the opening formed by the two plates not pressed together is 40-80°.

3. The method for processing a high-strength and tough stainless steel / carbon steel composite plate according to claim 1 or 2, characterized in that: In step S2, the length of the line spot is consistent with the width of the plate, the width of the line spot is 0.7 to 2 times the sum of the thicknesses of the two plates, and the angle between the line spot and the horizontal direction is 0 to 17 degrees.

4. The method for processing a high-strength and tough stainless steel / carbon steel composite plate according to claim 1, characterized in that: In the step S2, the rolling rate of the rolling mill is 0.5 to 3 m / min, and the rolling reduction ratio is 25 to 60%.

5. The method for processing a high-strength and tough stainless steel / carbon steel composite plate according to claim 1, characterized in that: In step S3, the length of the homogenized light spot is consistent with the width of the stainless steel / carbon steel composite plate, high-power laser and low-power laser are alternately irradiated to the stainless steel surface, and the heating temperature of the laser surface annealing area is monitored in real time using a pyrometer.

6. The method for processing a high-strength and tough stainless steel / carbon steel composite plate according to claim 5, characterized in that: The maximum heating temperature of the high-power laser irradiation area on the stainless steel surface is controlled at 850-1100°C, and the maximum heating temperature of the low-power laser irradiation area is controlled at 500-680°C.

7. The method for processing a high-strength and tough stainless steel / carbon steel composite plate according to claim 6, characterized in that: In the step S3, the width of a single high-power laser irradiation area or a low-power laser irradiation area is 0.5-2 mm.

8. The method for processing a high-strength and tough stainless steel / carbon steel composite plate according to claim 1, characterized in that: The material of high-strength carbon steel plate is low-alloy steel with a tensile strength ≥600MPa.

9. The method for processing a high-strength and tough stainless steel / carbon steel composite plate according to claim 1, characterized in that: In the step S1, after being polished with sandpaper, wire brush or abrasive belt, the roughness Ra of the surface to be composited of the high-strength carbon steel plate and the stainless steel plate is 3.2-6.3 μm.

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