Production process of iron-nickel stainless steel clad plate

Abstract

The present application belongs to the technical field of stainless steel clad plate, and particularly relates to a production process of iron-nickel stainless steel clad plate, which comprises the following steps: performing plasma sputtering cleaning on a carbon steel base layer; performing laser micro-cladding treatment on an iron-nickel stainless steel clad layer to form a micro-groove array, and prepositioning a nano nickel-titanium alloy transition layer in the micro-groove array; performing explosive compounding in a helium and argon mixed gas environment with an oxygen content of less than or equal to 10 ppm, so that the carbon steel base layer and the iron-nickel stainless steel clad layer are metallurgically combined at the interface to form a clad plate blank; heating and holding the clad plate blank, and then hot-rolling and water-cooling the clad plate blank to below 500 DEG C; and placing the rolled clad plate blank in a nitrogen and hydrogen mixed gas for isolation annealing. The present application improves the bonding strength and shear strength by constructing an interface gradient diffusion layer composite structure in a nano scale, inhibits interface oxidation and stress concentration in the rolling process by asynchronous rolling and nano thermal barrier coating, and improves the pitting potential of the iron-nickel stainless steel clad layer by synergistic regulation of multi-stage controlled cooling and diffusion barrier annealing.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of stainless steel clad plate, in particular to a production process of iron-nickel stainless steel clad plate. BACKGROUND

[0002] Iron-nickel stainless steel clad plate is widely used in deep-sea oil and gas pipelines, pressure vessels and other high-corrosion and high-pressure environments due to its high strength of carbon steel and corrosion resistance of stainless steel. In the existing production process, explosive cladding method is widely used due to its high energy bonding characteristics, but in the process of cladding of heterogeneous materials of iron-nickel stainless steel and carbon steel, the following key technical bottlenecks are still faced:

[0003] The interface bonding quality and element diffusion control are insufficient, and traditional explosive cladding process usually adopts mechanical polishing or single acid pickling pretreatment, which is difficult to realize atomic-level cleaning of the interface. The sudden diffusion of elements such as Fe, Cr and Ni between carbon steel and stainless steel caused by high temperature in explosive moment is easy to form brittle intermetallic compounds, and the interface shear strength is generally lower than 250 MPa, and the carbon element concentration gradient fluctuation can reach 8-12 at% / μm, which significantly reduces the interface toughness. In addition, the interface oxidation layer caused by air residues in the explosion process will hinder metallurgical bonding, which needs to rely on subsequent high-temperature rolling to compensate, resulting in grain coarsening and corrosion resistance reduction.

[0004] The dynamic bonding process is poor in controllability, and the conventional explosive cladding adopts single explosive velocity explosive (1800-2200 m / s) and static air environment, which leads to mismatch of collision speed and angle of composite material and base material. Especially for the composite plate with thickness ratio > 10:1, local uncombined area (defect area ratio > 0.1%) is easy to appear, and the residual stress concentration caused by explosive shock wave increases the risk of delamination of the composite plate during subsequent rolling. Although some studies have tried to introduce argon protection, the dynamic flow characteristics of He / Ar mixed gas are not optimized, and the interface purification effect is limited.

[0005] The rolling and heat treatment process lacks coordination, and the existing process usually adopts uniform reduction rate hot rolling combined with air cooling, which leads to excessive thickness of the interface diffusion layer (>1.2 μm), and the pearlite of the carbon steel base layer is coarsened due to insufficient cooling rate (<5℃ / s), and the yield strength can only reach 295-325 MPa. At the same time, the annealing process lacks diffusion barrier design, and Cr 23 C6 carbides are precipitated along the interface when the temperature is above 600℃, which reduces the pitting resistance potential of iron-nickel stainless steel clad layer to below 0.2V (vs. SCE), which seriously restricts its service life in Cl- environment.

[0006] Therefore, it is urgent to develop an iron-nickel stainless steel clad plate preparation method with controllable interface gradient and precise coupling of process parameters. SUMMARY

[0007] In order to solve the above problems, the present application provides an iron-nickel stainless steel clad plate and a production process thereof, which solves the problems of insufficient interface bonding quality and element diffusion control, poor controllability of dynamic bonding process and lack of synergy of rolling and heat treatment process in the existing iron-nickel stainless steel clad plate process.

[0008] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: an iron-nickel stainless steel clad plate production process, characterized by comprising the following steps:

[0009] Step one, surface gradient activation treatment:

[0010] The carbon steel base layer is subjected to plasma sputtering cleaning, the working gas pressure is 0.1-0.5 Pa, the power is 200-500 W, and the treatment time is 5-15 minutes;

[0011] The iron-nickel stainless steel clad layer is subjected to laser micro-cladding treatment, the laser parameters are wavelength 1064 nm and pulse frequency 20-50 kHz, a micro-groove array with a width of 10-30 μm and a depth of 5-15 μm is formed, and a nanometer nickel-titanium alloy transition layer with a thickness of 0.5-0.55 μm is pre-placed in the micro-groove array;

[0012] Step two, dynamic inert atmosphere explosive compounding:

[0013] The explosive compounding is carried out in a mixed gas environment of helium and argon with oxygen content ≤10 ppm, the layered explosive is laid, the upper layer explosive has a detonation velocity of 2000-2500 m / s, the lower layer explosive has a detonation velocity of 1500-1800 m / s, the upper layer explosive and the lower layer explosive are detonated to realize the interface metallurgical bonding of the carbon steel base layer and the iron-nickel stainless steel clad layer to form a clad plate blank;

[0014] Step three, multi-stage controlled rolling and controlled cooling:

[0015] The clad plate blank formed in step two is heated to 1050-1150℃ and kept for 30-60 minutes, is hot-rolled at a total reduction rate of 50-70%, and is water-cooled to below 500℃ at a cooling rate of 10-30℃ / s after finishing rolling;

[0016] Step four, interface diffusion barrier annealing:

[0017] The clad plate blank after rolling in step three is placed in a mixed gas of nitrogen and hydrogen, is heated to 600-750℃ at a rate of 5-10℃ / min and kept for 1-3 hours, and is cooled to below 200℃ at a cooling rate of ≤5℃ / min.

[0018] Further, the scanning path of the laser micro-cladding treatment in step one is a cross grid shape, and the grid angle is 60-90°.

[0019] Further, the mixing ratio of helium and argon in step two is 1:3-3:1, and the mixing ratio of nitrogen and hydrogen in the mixed gas in step four is 95:5.

[0020] Further, the thickness ratio of the carbon steel base layer to the iron-nickel stainless steel complex layer in step two is 5:1-20:1.

[0021] Further, the hot rolling in step three adopts an asynchronous rolling process, and the speed difference ratio of the upper and lower rollers ranges from 1.05 to 1.2, and a 15-micron-thick nano-Al2O3 thermal barrier coating is sprayed after each pass.

[0022] Further, the surface of the composite plate blank is sandblasted before annealing in step four, and the roughness Ra is 3-8 microns.

[0023] Further, the composite interface of the composite plate blank after explosion compounding in step two is ultrasonically inspected, and the defect area ratio is less than or equal to 0.1%.

[0024] Further, the composite plate blank after rolling in step three is additionally subjected to one pass of warm rolling at a temperature of 300-500 DEG C and a reduction of 5-10%.

[0025] An iron-nickel stainless steel composite plate is prepared by the production process of the iron-nickel stainless steel composite plate, which comprises a carbon steel base layer and an iron-nickel stainless steel complex layer, and an interface gradient diffusion layer is arranged between the carbon steel base layer and the iron-nickel stainless steel complex layer, the thickness of the interface gradient diffusion layer is 0.2-0.8 microns, the carbon element concentration gradient change of the interface gradient diffusion layer is less than or equal to 5 at% per micron, the bonding strength of the carbon steel base layer and the iron-nickel stainless steel complex layer is greater than or equal to 400 MPa, and the interface shear strength of the carbon steel base layer and the iron-nickel stainless steel complex layer is greater than or equal to 350 MPa.

[0026] Further, the surface pitting corrosion potential of the iron-nickel stainless steel complex layer is greater than or equal to 350 mV (vs. SCE), the yield strength of the carbon steel base layer is greater than or equal to 355 MPa, and the elongation is greater than or equal to 25%.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] 1. The composite pretreatment of plasma sputtering and laser micro-cladding constructs an interface gradient diffusion layer composite structure in nanometer scale, so that the interface carbon element concentration gradient is less than or equal to 5 at% per micron, and the bonding strength is increased by more than 60%.

[0029] 2. The mixed gas of helium and argon is used to control the detonation velocity, so that the interface oxygen pollution is reduced to less than 10 ppm, and the asynchronous rolling and nano thermal barrier coating are used to effectively inhibit the interface oxidation and stress concentration in the rolling process.

[0030] 3. The multi-stage controlled cooling and diffusion barrier annealing are cooperatively regulated, so that the point corrosion resistance potential of the iron-nickel stainless steel clad layer is greater than or equal to 350 mV, the yield strength of the base layer is greater than 355 MPa, and the comprehensive performance is significantly better than the prior art level. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0032] Step one, surface gradient activation treatment

[0033] The carbon steel base layer can adopt carbon structural steel such as Q345R, Q235B, SA516Gr70, etc., the iron-nickel stainless steel clad layer can adopt nickel-containing stainless steel such as 304, 316L, 317L, 904L, etc., and the thickness ratio of the carbon steel base layer to the iron-nickel stainless steel clad layer is controlled to be 5:1-20:1.

[0034] The surface of the carbon steel base layer is cleaned by plasma sputtering using a laser cleaning device, the working pressure is set to 0.3 Pa, the power is 350 W, and the treatment time is 10 minutes, so that the surface oxide film is removed to Sa3 level cleanliness. The iron-nickel stainless steel clad layer is treated by grid-shaped micro-cladding using a fiber laser, the laser parameters are: wavelength 1064 nm, pulse frequency 20-50 kHz, scanning speed 800 mm / s, a micro-groove array with a width of 10-30 μm and a depth of 5-15 μm is formed, and the grid angle is 60°-90°. A 0.5-0.55 μm thick nano nickel-titanium alloy transition layer is deposited in the groove by magnetron sputtering, the titanium content in the nickel-titanium alloy transition layer ranges from 10 to 30 wt%, and the sputtering chamber vacuum degree is 5×10 -3 Pa.

[0035] The surface impurities are removed by high-energy ion bombardment and an active surface is obtained by plasma cleaning, the contact angle is reduced to below 15°, at the same time, the laser micro-melting generates a rapid solidification structure, the grain is refined to a sub-micron level, and the nickel-titanium alloy transition layer can relieve the interfacial thermal stress.

[0036] Step two, dynamic inert atmosphere explosion cladding

[0037] The closed explosion chamber is filled with helium and argon mixed gas, the mixing ratio of helium and argon is 1:3-3:1, and the oxygen content is controlled to be less than or equal to 5 ppm. A double-layer explosive arrangement is adopted: the upper layer explosive has a detonation velocity of 2000-2500 m / s, for example, RDX explosive with a thickness of 50 mm is used, and the initiation detonation velocity is 2300 m / s; the lower layer explosive has a detonation velocity of 1500-1800 m / s, for example, ANFO explosive with a thickness of 80 mm is used, and the initiation detonation velocity is 1650 m / s. The preferred initiation detonation velocity difference is less than or equal to 650 m / s, the explosion gas pressure peak value is greater than or equal to 15 GPa, the interface instantaneous temperature reaches 2000 DEG C, and the duration is less than 1 ms. Immediately after compounding, the interface is detected by a 10 MHz ultrasonic probe to ensure that the defect area is less than or equal to 0.1%, and the compounded slab is obtained.

[0038] The thermal conductivity of the helium and argon mixed gas is 0.25 W / m·K, which is 30% lower than that of pure Ar, which slows down the cooling rate of the compounding interface, and at the same time, the explosion shock wave causes metal jet on the contact surface, which removes the surface oxide; after compounding, the interface forms an interface gradient diffusion layer, which improves the bonding strength.

[0039] Step three, multi-stage controlled rolling and controlled cooling

[0040] A four-high reversible rolling mill is used, and the speed difference ratio range of the upper and lower rollers is set to 1.05-1.2; the rolling is divided into four stages:

[0041] The initial rolling stage: 1100 DEG C for 45 min, the first pass reduction is 35%, the rolling speed is 0.8 m / s, and after rolling, 15 μm thick Al2O3 thermal barrier coating is sprayed immediately;

[0042] The finish rolling stage: the final rolling temperature is 890 DEG C, the last pass reduction is 5%, the rolling force is controlled to be 2800 kN, and the total reduction of the compounded slab after rolling is controlled to be 50%-70%;

[0043] The warm rolling process: one pass of warm rolling is added to the compounded slab after finish rolling, the temperature is 300-500 DEG C, and the reduction is 5%-10%;

[0044] The cooling adopts a laminar water curtain, the water curtain pressure is 0.35 MPa, the cooling gradient is controlled to be 10-30 DEG C / s, and the final cooling temperature is controlled to be below 500 DEG C;

[0045] Shear strain is generated by asynchronous rolling to promote the formation of <110> texture; at the same time, the Al2O3 coating reduces the heat transfer of the roller and inhibits the surface recrystallization; the introduction of the warm rolling process avoids the martensitic phase transition.

[0046] Step four, interface diffusion barrier annealing

[0047] The sand blasting treatment adopts 60 mesh brown corundum sand with a pressure of 0.6 MPa to obtain a rough surface with Ra = 5.23-8 μm. Two-stage annealing is carried out in an atmosphere with a mixing ratio of nitrogen and hydrogen of 95:5:

[0048] Fast heating stage: heating at 5-10 ℃ / min to 600-750 ℃;

[0049] Constant temperature holding: holding at 600-750 ℃ for 1-3 hours;

[0050] Slow cooling stage: cooling at a rate of ≤5 ℃ / min to below 200 ℃.

[0051] By introducing compressive residual stress (-350 MPa) through sand blasting, the rolling tensile stress is eliminated, and the interface oxide is reduced by hydrogen (Cr2O3 + H2→ 2Cr + 3H2O, ΔG = -285 kJ / mol).

[0052] An iron-nickel stainless steel clad plate is prepared by the above-mentioned iron-nickel stainless steel clad plate production process, the iron-nickel stainless steel clad plate comprises a carbon steel base layer and an iron-nickel stainless steel clad layer, an interface gradient diffusion layer is arranged between the carbon steel base layer and the iron-nickel stainless steel clad layer, the thickness of the interface gradient diffusion layer is 0.2-0.8 μm, the carbon element concentration gradient change of the interface gradient diffusion layer is ≤5 at% / μm, the bonding strength of the carbon steel base layer and the iron-nickel stainless steel clad layer is ≥400 MPa, and the interface shear strength of the carbon steel base layer and the iron-nickel stainless steel clad layer is ≥350 MPa

[0053] The technical scheme of the present application is described in detail below in combination with examples, but the protection scope of the present application is not limited to the examples. The performance tests of the examples and comparative examples are carried out in accordance with GB / T228.1 "Metallic Materials Tensile Test", GB / T232 "Metallic Materials Bending Test Method" and ASTM G61 "Standard Test Method for Electrochemical Critical Pitting Potential of Stainless Steels by the Cyclic Polarization Method".

[0054] Example One

[0055] Step One, Surface Gradient Activation Treatment:

[0056] The carbon steel base layer (Q235B, thickness 20 mm) is cleaned by argon plasma sputtering, the working gas pressure is 0.3 Pa, the power is 350 W, and the treatment time is 10 minutes;

[0057] The iron-nickel stainless steel clad layer (SUS316L, thickness 4 mm) is subjected to laser micro-cladding treatment, the laser wavelength is 1064 nm, the pulse frequency is 30 kHz, the scanning path is a 75° cross grid, a micro groove array with a width of 20 μm and a depth of 10 μm is formed, and a nanometer nickel-titanium alloy layer (Ni-20wt%Ti) with a thickness of 0.5 μm is pre-placed in the micro groove array.

[0058] Step two, dynamic inert atmosphere explosive compounding:

[0059] The explosive environment is a mixture of helium and argon gas (ratio 1:3), and the oxygen content is ≤8 ppm;

[0060] The detonation velocity of the upper explosive is 2000 m / s, the detonation velocity of the lower explosive is 1500 m / s, and the thickness ratio of the carbon steel base layer to the iron-nickel stainless steel complex layer is 5:1;

[0061] After explosive compounding, ultrasonic flaw detection shows that the defect area accounts for 0.08%.

[0062] Step three, multi-stage controlled rolling and controlled cooling:

[0063] Heating to 1050℃ for 30 minutes, total reduction rate 50%, using asynchronous rolling (roller speed difference ratio 1.105), final rolling temperature 850℃;

[0064] After each pass, spray nano-Al2O3 thermal barrier coating (thickness 15μm);

[0065] After rolling, water cooling to 480℃ at 10℃ / s.

[0066] Step four, interface diffusion barrier annealing:

[0067] Before annealing, the composite plate is sandblasted (roughness Ra=5μm);

[0068] In a mixture of nitrogen-hydrogen gas (95:5), heat to 650℃ at 5℃ / min and hold for 2 hours, cooling rate 4℃ / min.

[0069] Experimental results:

[0070] The interface gradient diffusion layer is 0.5μm thick, and the carbon element concentration gradient changes by 3.8at% / μm;

[0071] Bonding strength 425MPa, interface shear strength 378MPa;

[0072] Iron-nickel stainless steel complex layer pitting potential 380mV (vs. SCE), carbon steel base layer yield strength 375MPa, elongation 28%.

[0073] Example two

[0074] Step one, surface gradient activation treatment:

[0075] Carbon steel base layer (Q345R, thickness 25mm) plasma cleaning parameters: 0.4Pa, 400W, 12 minutes;

[0076] Iron-nickel stainless steel clad layer (SUS304, thickness 2.5mm) laser micro-cladding parameters: pulse frequency 40kHz, micro-groove width 25μm, depth 12μm, preset thickness of nanometer nickel-titanium layer (Ni-15wt%Ti) 0.525μm.

[0077] Step two, dynamic inert atmosphere explosive compounding:

[0078] Mixed gas helium:argon = 1:1, oxygen content ≤6ppm;

[0079] Upper explosive velocity 2300m / s, lower explosive velocity 1700m / s, thickness ratio of carbon steel base layer to iron-nickel stainless steel clad layer 10:1;

[0080] Explosive interface defect area ratio 0.06%.

[0081] Step three, multi-stage controlled rolling and controlled cooling:

[0082] Heating to 1100℃ for 45 minutes, total reduction 65%, asynchronous roll speed difference ratio 1.15, finish rolling temperature 900℃;

[0083] After rolling, water cooling to 450℃ at 25℃ / s, adding a pass of warm rolling (temperature 400℃, reduction 8%).

[0084] Step four, interface diffusion barrier annealing:

[0085] Sandblasting treatment roughness Ra = 6μm;

[0086] In nitrogen-hydrogen mixed gas (95:5), heating to 700℃ at 8℃ / min, holding for 1.5 hours, cooling rate 3℃ / min.

[0087] Experimental results:

[0088] Interface gradient diffusion layer thickness 0.7μm, carbon concentration gradient 4.2at% / μm;

[0089] Bonding strength 412MPa, shear strength 365MPa;

[0090] Iron-nickel stainless steel clad layer pitting corrosion potential 360mV, carbon steel yield strength 385MPa, elongation 26%.

[0091] Example three

[0092] Step one, surface gradient activation treatment:

[0093] Carbon steel base layer (SA516Gr70, thickness 60mm) plasma cleaning parameters: 0.2Pa, 300W, 8 minutes;

[0094] Iron-nickel stainless steel clad layer (SUS317L, thickness 3mm) Laser parameters: pulse frequency 25 kHz, micro-groove width 15 μm, depth 8 μm, pre-set thickness of nanometer nickel-titanium layer (Ni-25wt%Ti) 0.55 μm.

[0095] Step two, dynamic inert atmosphere explosive compounding:

[0096] Mixed gas helium:argon = 3:1, oxygen content ≤5ppm;

[0097] Upper explosive velocity 2500m / s, lower explosive velocity 1800m / s, thickness ratio of carbon steel base layer to iron-nickel stainless steel clad layer 20:1;

[0098] Defect area ratio of explosive interface 0.1%.

[0099] Step three, multi-stage controlled rolling and controlled cooling:

[0100] Heating to 1150℃ for 60 minutes, total reduction 70%, rolling speed difference ratio 1.2, finish rolling temperature 860℃;

[0101] Cooling rate after rolling 30℃ / s to 500℃.

[0102] Step four, interface diffusion barrier annealing:

[0103] Sandblasting treatment roughness Ra = 4 μm;

[0104] In nitrogen-hydrogen mixed gas (95:5), heating to 600℃ at 10℃ / min, holding for 3 hours, cooling rate 2℃ / min.

[0105] Experimental results:

[0106] Interface gradient diffusion layer thickness 0.3 μm, carbon concentration gradient 2.5at% / μm;

[0107] Bonding strength 435MPa, shear strength 392MPa;

[0108] Iron-nickel stainless steel clad layer pitting corrosion potential 410mV, carbon steel yield strength 395MPa, elongation 27%.

[0109] Comparative example

[0110] Traditional compounding process (using traditional explosive compounding and conventional rolling):

[0111] Carbon steel base layer (Q235B, thickness 20mm) and iron-nickel stainless steel clad layer (SUS316L, thickness 4mm) using conventional explosive compounding (air environment, oxygen content ≥200ppm);

[0112] Explosion parameters: single layer explosive detonation velocity 2100 m / s, thickness ratio of base layer to iron-nickel stainless steel clad layer 5:1;

[0113] After explosion, the interface defect area accounted for 0.035% of the total area.

[0114] Rolling process: direct hot rolling (total reduction rate 60%), roller synchronous speed difference ratio 1.0, no heat insulation coating was used, and the final rolling temperature was 900°C.

[0115] Annealing process: air annealing (600°C x 2h), no interface diffusion barrier treatment was performed.

[0116] Experimental results:

[0117] The interface bonding layer thickness was 1.8 μm, and the carbon element concentration gradient change was 9.6 at% / μm.

[0118] The bonding strength was 238 MPa, and the interface shear strength was 198 MPa.

[0119] The iron-nickel stainless steel clad layer had a pitting corrosion potential of 180 mV (vs. SCE), and the carbon steel base layer had a yield strength of 285 MPa and an elongation of 15%.

[0120] The interface cracking length accounted for 12% of the total length in the bending test, and the cyclic polarization curve showed obvious passivation film rupture.

[0121] The pitting corrosion performance and mechanical properties were significantly worse than those of Example One, Example Two, and Example Three.

[0122] Effect analysis of the example

[0123] Interface gradient diffusion layer control: In the example, a nano nickel-titanium alloy transition layer design and gradient annealing process were used to control the interface carbon element diffusion gradient ≤5 at% / μm (3.8 at% / μm in Example One), which significantly inhibited the interface embrittlement caused by carbon element migration.

[0124] Dynamic explosion cladding advantage: The layered explosive arrangement (Example Two upper layer explosive detonation velocity 2400 m / s) made the iron-nickel stainless steel clad layer and the base layer have a controllable collision speed, combined with an interface defect rate ≤0.01% (Example Three 0.005%), which was better than the traditional explosion cladding process (usually defect rate >0.03%).

[0125] Asynchronous rolling and heat insulation coating synergistic effect: In Example One, the roller speed difference ratio was 1.1, and the nano Al2O3 coating was used, which reduced the interface temperature rise during rolling by about 50°C, and the grain size was refined to 8-12 μm (grain size in the comparative example was 20-30 μm).

[0126] Corrosion resistance is improved: the pitting resistance potential of the iron-nickel stainless steel clad layer in Example Three is 0.41V (0.22V in the comparative example), due to the dense nanocrystalline layer (grain size ≤100nm) formed by laser micro-cladding and the hydrogen reduction of the surface oxide film in the annealing process.

[0127] The present application improves the interface bonding strength of the iron-nickel stainless steel clad plate to ≥400MPa (425MPa in Example One), the shear strength to ≥350MPa (392MPa in Example Three), and the pitting resistance and the mechanical properties of the base material, which is suitable for corrosion-resistant structural parts and deep-sea equipment manufacturing.

[0128] Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions described in the foregoing embodiments or make equivalent replacements to some of the technical features, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A production process for iron-nickel-stainless steel composite plates, characterized in that, Includes the following steps: Step 1: Surface gradient activation treatment: Plasma sputtering cleaning is performed on carbon steel substrates. The working pressure is 0.1-0.5 Pa, the power is 200-500 W, and the processing time is 5-15 minutes. Laser micro-cladding is performed on the iron-nickel stainless steel cladding layer. The laser parameters are wavelength 1064nm and pulse frequency 20-50kHz, forming a micro-groove array with a width of 10-30μm and a depth of 5-15μm. A nano-nickel-titanium alloy transition layer with a thickness of 0.5-0.55μm is pre-placed in the micro-groove array. Step 2: Dynamic inert atmosphere explosion recombination: The explosive composite process is carried out in a mixed gas environment of helium and argon with an oxygen content of ≤10ppm. Layered explosives are used, with the upper explosive having a detonation velocity of 2000-2500m / s and the lower explosive having a detonation velocity of 1500-1800m / s. The upper and lower explosives are detonated to achieve interfacial metallurgical bonding between the carbon steel base layer and the iron-nickel stainless steel cladding to form a composite slab. Step 3: Multi-stage controlled rolling and cooling: The composite slab formed in step two is heated to 1050℃~1150℃ and held for 30~60 minutes. It is then hot rolled with a total reduction of 50%~70% and a final rolling temperature ≥850℃. After rolling, it is water cooled to below 500℃ at a rate of 10~30℃ / s. In step three, the hot rolling adopts an asynchronous rolling process, with the speed difference ratio between the upper and lower rolls ranging from 1.05 to 1.2, and a 15μm thick nano Al2O3 heat insulation coating is sprayed after each rolling pass. Step 4: Interface diffusion barrier annealing: The composite slab rolled in step three is placed in a mixture of nitrogen and hydrogen gas, heated to 600-750℃ at a rate of 5-10℃ / min and held for 1-3 hours, and then cooled to below 200℃ at a rate of ≤5℃ / min.

2. The production process of iron-nickel-stainless steel composite plate according to claim 1, characterized in that: The scanning path for the laser micro-cladding process in step one is a cross-grid pattern with grid angles of 60° to 90°.

3. The production process of iron-nickel-stainless steel composite plate according to claim 1, characterized in that: In step two, the mixing ratio of helium and argon is 1:3 to 3:1, and in step four, the mixing ratio of nitrogen and hydrogen is 95:

5.

4. The production process of iron-nickel-stainless steel composite plate according to claim 1, characterized in that: In step two, the thickness ratio of the carbon steel base layer to the iron-nickel stainless steel cladding layer in the explosive composite process is 5:1 to 20:

1.

5. The production process of iron-nickel-stainless steel composite plate according to claim 1, characterized in that: Step 4: Before intermediate annealing, the surface of the composite slab is sandblasted to a roughness of Ra=3~8μm.

6. The production process of iron-nickel-stainless steel composite plate according to claim 1, characterized in that: Step 2: After the explosive bonding process, ultrasonic testing is performed on the composite interface of the composite slab, and the defect area ratio is ≤0.1%.

7. The production process of iron-nickel-stainless steel composite plate according to claim 1, characterized in that: The composite slab after step three rolling is subjected to an additional warm rolling at a temperature of 300–500℃ and a reduction rate of 5%–10%.

8. A type of iron-nickel-stainless steel composite plate, characterized in that, Prepared by any one of the production processes described in claims 1-7, the iron-nickel stainless steel composite plate comprises a carbon steel base layer and an iron-nickel stainless steel cladding layer, wherein an interface gradient diffusion layer is disposed between the carbon steel base layer and the iron-nickel stainless steel cladding layer, the thickness of the interface gradient diffusion layer is 0.2-0.8 μm, the carbon element concentration gradient change of the interface gradient diffusion layer is ≤5 at% / μm, the bonding strength between the carbon steel base layer and the iron-nickel stainless steel cladding layer is ≥400 MPa, and the interfacial shear strength between the carbon steel base layer and the iron-nickel stainless steel cladding layer is ≥350 MPa.

9. The iron-nickel-stainless steel composite plate according to claim 8, characterized in that, The surface pitting potential of the iron-nickel stainless steel cladding is ≥350mV (vs. SCE), the yield strength of the carbon steel base layer is ≥355MPa, and the elongation is ≥25%.