A nickel-based corrosion-resistant alloy-steel composite plate and its preparation method

Abstract

This invention belongs to the field of layered metal composite plate manufacturing technology, and provides a nickel-based corrosion-resistant alloy-steel composite plate and its preparation method. First, the surfaces to be composited are treated and then assembled. An explosive bonding process is performed to obtain a composite billet with a pre-bonded interface. This billet undergoes low-temperature recovery annealing, followed by heating and holding for a first pass of controlled rolling. Subsequent rolling passes are then performed at a temperature range lower than the aforementioned heating temperature to obtain the final rolled composite plate. The final rolling temperature is not lower than the lower limit of the sensitization temperature zone of the nickel-based alloy. Accelerated cooling allows the cladding layer to quickly pass through the sensitization temperature zone and cool below it. The explosive pre-locking interface decouples welding and elongation. Subsequent rolling is completed in a low-temperature range avoiding the sensitization temperature zone, resolving the contradiction between the high-temperature welding requirements and the anti-sensitization requirements of traditional processes. Low-temperature recovery annealing eliminates the defect of microcracks induced by the amorphous layer at the explosive interface during heating. The resulting composite plate possesses high interfacial bonding strength, excellent low-temperature toughness, and good corrosion resistance.

Description

Technical Field

[0001] This invention belongs to the field of layered metal composite plate manufacturing technology, and relates to a nickel-based corrosion-resistant alloy-steel composite plate and its preparation method. Background Technology

[0002] In the petrochemical industry, equipment such as hydrogenation reactors, heat exchangers, and separators operate under high temperature, high pressure, and corrosive media containing hydrogen sulfide and chloride ions for extended periods. Nickel-based corrosion-resistant alloy-steel composite plates are commonly used in engineering to manufacture these devices. Currently, nickel-based corrosion-resistant alloy-steel composite plates can be prepared using methods such as explosive bonding, rolling bonding, and explosive bonding followed by rolling. The explosive bonding followed by rolling method typically involves first using explosive bonding to establish an initial bonding interface between the cladding and the base layer, followed by subsequent heated rolling to adjust the plate shape, extend the thickness, and stabilize the interface. For thick-gauge composite plates, the cladding layer is relatively thin while the base layer is relatively thick, resulting in differences in rheological stress, plastic flow, and thickness-direction deformation distribution between the cladding and the base layer during hot rolling. If the heating temperature and rolling reduction are insufficient, the local weak bonding areas of the composite interface will be difficult to further compact, which will easily affect the stability of the interface bonding. If the heating temperature is increased or the high-temperature dwell time is extended, although it is beneficial to the interface bonding and plate shape extension, the nickel-based corrosion-resistant alloy cladding will spend more time in the sensitization temperature range during the subsequent cooling process, which will easily increase the risk of grain boundary precipitation and decreased resistance to intergranular corrosion.

[0003] Furthermore, under the influence of instantaneous high pressure, high-speed collision, and localized severe plastic deformation, the explosive composite interface will form a wavy interface, as well as localized high-strain hardening zones, residual stress concentration zones, and areas of inhomogeneous microstructure. If the explosive composite billet is directly introduced into the subsequent hot rolling process without proper stabilization treatment, these localized inhomogeneous interface areas may become weak points for microcrack propagation or interface slippage during heating and rolling deformation, affecting the interface stability during subsequent rolling extension. Conventionally increasing the heating temperature or extending the holding time cannot simultaneously solve the problems of interface stability and maintaining the corrosion resistance of the cladding layer; on the contrary, it may increase the risk of thermal exposure of the cladding layer within the sensitization temperature range.

[0004] Therefore, for nickel-based corrosion-resistant alloy-steel composite plates with a large total thickness, the technical problem that needs to be solved in the actual production of such composite plates is how to reduce the risk of stratification of the composite layer and maintain the low-temperature toughness of the base layer while maintaining the interfacial bonding strength through the coordinated control of low-temperature recovery annealing, low-temperature controlled rolling and post-rolling accelerated cooling, based on the pre-bonded interface formed by explosive bonding. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a nickel-based corrosion-resistant alloy-steel composite plate and its preparation method. First, the cladding layer and the base layer are surface-treated and explosively bonded to form a pre-bonded interface. Then, the plate undergoes low-temperature recovery annealing, low-temperature controlled rolling, and post-rolling accelerated cooling. This allows the composite plate to balance interface bonding stability, cladding corrosion resistance, and base layer low-temperature toughness under thick-gauge conditions. It is suitable for manufacturing composite plates for petrochemical pressure equipment, improving subsequent service reliability.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing a nickel-based corrosion-resistant alloy-steel composite plate, comprising the following steps: S1, using a nickel-based corrosion-resistant alloy plate as a cladding layer and a steel base plate as a base layer, the surfaces of the cladding layer and the base layer to be composited are treated and then assembled, and explosive composite is performed to obtain a composite blank with a pre-bonded interface. S2, the composite blank is subjected to low-temperature recovery annealing to obtain a recovery-treated blank; S3, the recovered billet is heated and kept at a certain temperature, and then subjected to the first pass of controlled rolling to obtain the first rolled billet; S4, within a temperature range lower than that described in S3 for heating and heat preservation, the first rolled billet is subjected to subsequent rolling passes to obtain a final rolled composite plate; S5, after rolling, the final rolled composite plate is accelerated cooled to obtain a nickel-based corrosion-resistant alloy-steel composite plate.

[0007] Preferably, in S1, the surface treatment is as follows: shot blasting or sandblasting is performed on the surface of the steel base plate to be laminated, so that the surface roughness Ra of the surface of the steel base plate to be laminated is 6-12μm; pickling or mechanical grinding is performed on the surface of the nickel-based corrosion-resistant alloy plate to be laminated, so as to remove the surface oxide layer.

[0008] Preferably, in S1, the explosive composite uses a low-detonation-velocity explosive with a detonation velocity of 2000-2500 m / s and a gap angle of 8°-12°.

[0009] Preferably, in S2, the temperature of the low-temperature recovery annealing is 450-550℃, and the holding time is 4-8h.

[0010] Preferably, in S3, the heating temperature is 970-1020℃, the holding time is 30-90min, and the reduction rate of the first pass controlled rolling is 25-35%.

[0011] Preferably, in S4, the rolling temperature of subsequent passes is 880-960℃, the single-pass reduction rate is 8-22%, and the final rolling temperature is not lower than 850℃.

[0012] Preferably, in S5, the accelerated cooling rate is 15-30℃ / s, and the accelerated cooling is any one of water mist cooling, air mist cooling or laminar flow cooling, so that the composite layer passes through the temperature range of 650-850℃ and is cooled to below 550℃, and then air-cooled to room temperature.

[0013] Preferably, the nickel-based corrosion-resistant alloy plate is any one of UNS N08825, UNS N06625, UNS N10276, and UNSN06022; the steel base plate is any one of SA-516 Gr.70N, SA-516 Gr.70, Q345R, and 16MnR.

[0014] In a second aspect, the present invention provides a nickel-based corrosion-resistant alloy-steel composite plate prepared by the preparation method described in the first aspect.

[0015] Preferably, the nickel-based corrosion-resistant alloy-steel composite plate includes a cladding layer and a base layer, the total thickness of the nickel-based corrosion-resistant alloy-steel composite plate is not less than 100mm, and the thickness of the cladding layer is 2.5-3.5mm.

[0016] During the cooling process after high-temperature processing, interstitial atoms, alloying elements, and crystal defects in nickel-based corrosion-resistant alloy cladding undergo redistribution. The nickel-based austenitic matrix has a face-centered cubic structure, where interstitial atoms such as carbon and nitrogen can occupy interstitial positions. Elements such as chromium, molybdenum, copper, iron, titanium, and niobium are distributed in the matrix as substitutional atoms. As the temperature decreases, interstitial atoms not fixed by stabilizing elements have a driving force to segregate towards high-energy sites such as grain boundaries, dislocations, deformation bands, and phase interfaces. For nickel-based corrosion-resistant alloys containing stabilizing elements such as titanium and niobium, some carbon and nitrogen preferentially form carbonitrides with the stabilizing elements, thereby reducing the content of free interstitial atoms participating in the precipitation of chromium-rich carbides at grain boundaries. However, under conditions of hot working, interfacial diffusion, and local compositional fluctuations, incompletely stabilized interstitial atoms may still participate in grain boundary precipitation reactions.

[0017] When the multilayer remains within the sensitization temperature range, carbon and nitrogen atoms acquire the thermal activation energy required for diffusion and migrate along grain boundaries, dislocation channels, and deformation bands. The atomic arrangement in the grain boundary region deviates from the periodic lattice within the grain, exhibiting higher free volume and structural defects. The migration energy barrier for interstitial atoms in the grain boundary region is lower than that within the grain, thus interstitial atoms are more likely to accumulate near the grain boundary. Chromium atoms migrate via substitutional diffusion, which depends on vacancy transitions, and its migration rate is lower than that of interstitial atoms. The rate of interstitial atom enrichment towards the grain boundary is inconsistent with the rate of chromium atom re-emergence from the grain interior to the grain boundary, making it easy for local elemental concentration gradients to form near the grain boundary.

[0018] Grain boundaries serve as heterogeneous nucleation sites for precipitates. The interfacial energy, dislocations, and structural defects at grain boundaries reduce the energy required for precipitate nucleation. Carbon atoms not fixed by stabilizing elements combine with chromium atoms near the grain boundaries to form chromium-rich carbides or chromium-containing precipitates. During precipitate growth, carbon atoms can be continuously supplied along the grain boundaries, while chromium atoms need to diffuse from the grain interior towards the vicinity of the grain boundaries to replenish them. Because the substitutional diffusion rate of chromium atoms is lower than the grain boundary diffusion rate of carbon atoms, chromium in the matrix surrounding the precipitates cannot be replenished in time after being consumed, resulting in chromium-depleted regions with chromium content below the average level of the matrix on both sides of the grain boundaries.

[0019] When the chromium content in chromium-depleted regions decreases, the formation and repair capabilities of localized passivation films decline. The corrosion resistance of nickel-based corrosion-resistant alloys depends on the formation of a chromium-rich oxide film on the surface. Molybdenum and copper contribute to improving repassivation and stability in acidic media under localized corrosion environments. After the formation of chromium-depleted regions at grain boundaries, the ability to form a protective oxide film in the adjacent grain boundary region is weaker than in the intragranular region. When corrosive media contact the stratified surface or enter the grain boundary region along microscopic defects, anodic dissolution preferentially occurs in the chromium-depleted region, and the corrosion reaction extends along the grain boundary, forming intergranular corrosion paths. In chloride-containing environments, chloride ions readily adsorb around passivation film defects, inclusions, and chromium-depleted regions, damaging the localized passivation film and promoting the hydrolysis of metal cations, leading to localized acidification. If the repassivation capability around the chromium-depleted region and precipitated phases is insufficient, the dissolution reaction within the pitting corrosion continues, increasing pitting sensitivity.

[0020] The sensitization process is jointly controlled by temperature and residence time, and its essence is a competition between interstitial atom segregation, precipitate nucleation and growth, and chromium replenishment diffusion. Within the sensitization temperature range, at excessively low temperatures, the diffusion capacity of interstitial atoms is limited, making it difficult for the precipitate to grow sufficiently. As the temperature increases, the migration rate of interstitial atoms towards grain boundaries and the growth rate of the precipitate increase, accelerating chromium consumption near the grain boundaries. When the replenishment diffusion of chromium is insufficient to offset the chromium consumption caused by precipitate growth, the chromium-depleted region gradually becomes continuous. If the temperature continues to rise to the range where the stability of the precipitate decreases, some precipitates undergo re-dissolution, and chromium re-enters the austenite matrix, weakening the chromium-depleted region. Therefore, the longer the time the stratum corneum spends traversing the sensitization temperature range during cooling, the greater the opportunity for grain boundary precipitation reactions and the continuity of the chromium-depleted region. When the traversal time is shortened, although there is a driving force for interstitial atom segregation, the precipitate is unlikely to grow to the extent of forming a continuous chromium-depleted region.

[0021] During post-rolling cooling of thick composite plates, the temperature drop in the cladding, base layer, and interface regions is controlled by heat conduction along the thickness direction. The cooling medium first removes heat from the plate surface; heat inside the plate needs to be conducted along the thickness direction to the surface before being carried away. As the base layer thickness increases, the overall heat capacity of the composite plate increases, and cooling near the interface and in the internal regions lags behind the surface region. If the pre-rolling heating temperature is too high, the time for the composite plate to cool from the high temperature to the sensitization temperature zone and continue through the sensitization temperature zone increases, resulting in a longer time for grain boundary precipitation reactions. Lowering the pre-rolling heating temperature and accelerating post-rolling cooling can shorten the residence time of the cladding in the sensitization temperature zone, limit the continuous migration of carbon and nitrogen to the grain boundaries, limit the growth of chromium-rich precipitates and the continuity of chromium-depleted regions, thereby maintaining the elemental basis required for the formation and re-passivation of the cladding passivation film.

[0022] During explosive bonding, the cladding layer and the base layer collide at high speed under detonation. The oxide film and adsorbed layer on the surface of the bonding interface are broken and expelled by the impact jet and shear deformation, exposing the fresh metal surface for contact. At the interface, the metal undergoes plastic flow under high pressure, shear, and local temperature rise, forming a wavy bonding interface. High strain concentration exists at the crests, troughs, and interface transition regions. The grains of the cladding layer and base layer near the interface undergo flattening, bending, refinement, and orientation changes, resulting in increased dislocation density and the formation of high strain hardening zones, residual stress concentration zones, and areas of inhomogeneity in local areas. If residual oxides, inclusions, or locally melted and solidified zones are present near the interface, these areas are prone to becoming stress concentration sites during subsequent heating and rolling processes.

[0023] It is worth further explaining that during the instantaneous high-pressure, high-speed collision process of explosive bonding, the surfaces to be bonded between the cladding layer and the base layer undergo intense plastic deformation in a very short time, accompanied by a significant adiabatic temperature rise. After the collision, the heat in the interface region is rapidly carried away through the rapid heat conduction between the two parent materials. Under such cooling conditions, the molten metal or highly disordered deformed layer in the local areas of the interface—especially the crests, troughs, and vortex regions of the wavy interface—does not have enough time to complete ordered crystallization through atomic diffusion, thus forming an amorphous layer or a nanocrystalline-amorphous mixed layer at the interface. This type of amorphous layer is thermodynamically metastable, has high free energy, lacks long-range periodicity in its atomic arrangement, and contains a large amount of free volume and residual stress.

[0024] During subsequent heating, when the temperature rises above the crystallization temperature of the amorphous layer, the amorphous layer undergoes a transformation from a metastable state to a stable crystalline phase (crystallization), a process accompanied by significant volume shrinkage. Simultaneously, the thermal stress generated between the amorphous layer and the two parent substrates due to the difference in their coefficients of thermal expansion is superimposed on the volume shrinkage stress from crystallization, resulting in a complex multiaxial stress state in localized areas of the interface. Because the crystallization transformation rate and volume shrinkage of the amorphous layer are not uniform across the interface, localized stress concentrations can easily exceed the interfacial bonding strength, inducing the initiation and propagation of microcracks at the interface. Once these microcracks form, they not only directly weaken the interfacial bonding strength but also become crack sources for interfacial slippage, delamination, and even macroscopic cracking during subsequent rolling deformation, severely deteriorating the interfacial integrity and low-temperature toughness of the composite plate.

[0025] During low-temperature recovery annealing, dislocations near the explosive recombination interface undergo slip, climb, and rearrangement. Some dislocation tangles transform into subgrain boundary structures, residual stress is released, and the stress gradient in the locally hardened zone decreases. This temperature range primarily promotes the recovery of deformed microstructures and stress relaxation, rather than driving the precipitation reaction at multilayer grain boundaries. After recovery treatment, the pre-bonded structure formed by explosive recombination at the interface is maintained, while the high-strain zone and residual stress concentration zone tend to stabilize, reducing the tendency for local crack propagation and slip instability at the interface during subsequent rolling.

[0026] In the low-temperature controlled rolling stage, the recovery-treated billet is rolled at a temperature lower than that under conventional high-temperature welding conditions. Since the explosive bonding has already formed a pre-bonded interface, the rolling process does not rely on prolonged high-temperature diffusion to complete the main welding. Instead, compression and shear deformation further compact, extend, and stabilize the pre-bonded interface. The first pass of controlled rolling compresses and closes local micropores, micro-gap areas, and weakly bonded regions at the interface, elongating the wavy interface along the rolling direction and smoothing the interface waveform. Subsequent passes of rolling extend the cladding layer and the base layer together, making the interface bonding area continuous, and adjusting the cladding layer thickness and shape. The lower temperature rolling reduces the residence time of the cladding layer at high temperatures and also limits the diffusion distance of elements such as carbon and iron from the base layer to the cladding layer side, reducing the risk of brittle precipitates or continuous chromium-depleted zones near the interface.

[0027] Accelerated cooling after rolling allows the strata to rapidly pass through the temperature range where grain boundary precipitation reactions are active, reducing the time for interstitial atoms to segregate towards grain boundaries and for chromium-rich precipitates to grow. Even if nucleation sites exist at grain boundaries, precipitates are unlikely to grow continuously in a short time, and chromium-depleted regions are difficult to connect along grain boundaries. After rolling deformation, the base layer undergoes controlled cooling, which inhibits grain growth, controls the microstructure transformation path, and maintains low-temperature impact toughness. Through the continuous effects of explosive pre-bonding, low-temperature recovery stabilization, low-temperature controlled rolling compaction and extension, and accelerated cooling after rolling, a stable bonding structure is formed at the interface of the composite plate. The strata reduce the tendency for the chromium-depleted regions at grain boundaries to continue, and the base layer maintains the microstructure required for load-bearing capacity and low-temperature toughness.

[0028] In summary, this invention does not rely solely on increasing rolling temperature or extending high-temperature holding time to achieve interfacial bonding. Instead, it uses the pre-bonded interface formed by explosive bonding as the basis for subsequent controlled rolling. Low-temperature recovery annealing reduces residual stress and local microstructural inhomogeneity at the explosive interface. Lower-temperature controlled rolling then achieves interface compaction, plate shape extension, and thickness coordination. Accelerated cooling after rolling limits the residence time of the cladding layer within the sensitization temperature range. This process distinguishes the interfacial bonding strengthening process from the cladding layer sensitization control process in terms of time and temperature paths, avoiding the need for high-temperature, long-term diffusion to achieve interfacial stability. This reduces the risk of chromium-depleted cladding at grain boundaries and maintains the required load-bearing strength and low-temperature toughness of the base layer. Therefore, the composite plate can simultaneously achieve a stable interfacial bonding state, resistance to intergranular corrosion and pitting corrosion in the cladding layer, and low-temperature service adaptability of the base layer under thick-gauge conditions.

[0029] Compared with existing technologies, the advantages of this invention are as follows: This invention first forms a pre-bonded interface between the cladding and the base layer through explosive bonding, and then utilizes low-temperature recovery annealing to reduce residual stress and local microstructure inhomogeneity near the explosive bonding interface, resulting in a more stable interface state for the composite billet before subsequent rolling. Subsequent low-temperature controlled rolling allows the rolling process to primarily handle interface compaction, plate shape extension, and thickness coordination, reducing reliance on high-temperature, long-term diffusion welding and thus lowering the risk of element diffusion and grain boundary precipitation in the cladding at high temperatures. Accelerated cooling after rolling shortens the residence time of the cladding in the sensitization temperature range, inhibiting the continuity of chromium-depleted grain boundary regions and helping to maintain the cladding's resistance to intergranular corrosion and pitting corrosion. Simultaneously, the base layer maintains its load-bearing strength and low-temperature toughness under controlled thermal deformation and cooling conditions. Therefore, the resulting composite plate can balance interface bonding stability, cladding corrosion resistance, and base layer service reliability, making it suitable for manufacturing thick-gauge composite plates for petrochemical pressure equipment. Attached Figure Description

[0030] Figure 1 This is a surface observation image of Example 1 of the present invention after an intergranular corrosion test; Figure 2 This is a surface observation image of Embodiment 1 of the present invention after a pitting corrosion test. Detailed Implementation

[0031] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0032] The chemical reagents used in the embodiments and comparative examples of this invention are all commercially available products and have not undergone any further purification treatment.

[0033] Example 1 This embodiment provides a method for preparing a nickel-based corrosion-resistant alloy-steel composite plate, including the following steps: S1. Using UNS N08825 nickel-based corrosion-resistant alloy plate as the cladding layer and SA-516 Gr.70N steel plate as the base layer, the surface of the steel base plate to be composited is shot-peened to achieve a surface roughness Ra of 10μm. The surface of the nickel-based corrosion-resistant alloy plate to be composited is pickled to remove the surface oxide layer. After surface treatment, the cladding layer and the base layer are assembled with an open gap and detonated using low-velocity ammonium nitrate explosive with a detonation velocity of 2160m / s and a gap angle of 12° to obtain a composite blank with a pre-bonded interface. S2, the composite blank is subjected to low-temperature recovery annealing treatment at a temperature of 520°C and a holding time of 4 hours to obtain the recovery-treated blank; S3, the recovery treatment billet is heated to 970°C and held for 70 minutes, and then the first pass of controlled rolling is performed. The reduction rate of the first pass of controlled rolling is 32%, and the first rolled billet is obtained. S4. Within a temperature range lower than the heating temperature described in step S3, the first rolled billet is rolled in subsequent passes. The rolling temperature of each subsequent pass is controlled at 905°C, the single-pass reduction rate of each subsequent pass is 22%, and the final rolling temperature is not lower than 850°C to obtain a final rolled composite plate. S5. After rolling, the final rolled composite plate is subjected to accelerated cooling at a rate of 15°C / s. The accelerated cooling is laminar flow cooling, which allows the cladding layer to pass through a temperature range of 650-850°C and cool to below 500°C. Subsequently, it is air-cooled to room temperature to obtain a nickel-based corrosion-resistant alloy-steel composite plate. The total thickness of the obtained nickel-based corrosion-resistant alloy-steel composite plate is 120mm, and the thickness of the cladding layer is 3.2mm.

[0034] Example 2 This embodiment provides a method for preparing a nickel-based corrosion-resistant alloy-steel composite plate, including the following steps: S1. Using UNS N08825 nickel-based corrosion-resistant alloy plate as the cladding layer and SA-516 Gr.70N steel plate as the base layer, the surface of the steel base plate to be laminated is sandblasted to achieve a surface roughness Ra of 6μm. The surface of the nickel-based corrosion-resistant alloy plate to be laminated is mechanically ground to remove the surface oxide layer. After surface treatment, the cladding layer and the base layer are assembled with an open gap, and low-detonation-velocity ammonium nitrate explosive is used for explosive lamination with a detonation velocity of 2500m / s and a gap angle of 9° to obtain a composite blank with a pre-bonded interface. S2, the composite blank is subjected to low-temperature recovery annealing treatment at a temperature of 450°C and a holding time of 7 hours to obtain the recovery-treated blank; S3, the recovery treatment billet is heated to 1005°C and held for 30 minutes, and then the first pass of controlled rolling is performed. The reduction rate of the first pass of controlled rolling is 25%, and the first rolled billet is obtained. S4. Within a temperature range lower than the heating temperature described in step S3, the first rolled billet is rolled in subsequent passes. The rolling temperature of each subsequent pass is controlled at 960°C, the single-pass reduction rate of each subsequent pass is 12%, and the final rolling temperature is not lower than 850°C to obtain a final rolled composite plate. S5. After rolling, the final rolled composite plate is subjected to accelerated cooling at a rate of 25°C / s. The accelerated cooling is air mist cooling, which allows the cladding layer to pass through a temperature range of 650-850°C and cool down to below 550°C. Then, it is air-cooled to room temperature to obtain a nickel-based corrosion-resistant alloy-steel composite plate. The total thickness of the obtained nickel-based corrosion-resistant alloy-steel composite plate is 100mm, and the thickness of the cladding layer is 2.5mm.

[0035] Example 3 This embodiment provides a method for preparing a nickel-based corrosion-resistant alloy-steel composite plate, including the following steps: S1. Using UNS N08825 nickel-based corrosion-resistant alloy plate as the cladding layer and SA-516 Gr.70N steel plate as the base layer, the surface of the steel base plate to be composited is shot-peened to achieve a surface roughness Ra of 12μm. The surface of the nickel-based corrosion-resistant alloy plate to be composited is pickled to remove the surface oxide layer. After surface treatment, the cladding layer and the base layer are assembled with an open gap and detonated using low-velocity ammonium nitrate explosive at a detonation velocity of 2000m / s and a gap angle of 11° to obtain a composite blank with a pre-bonded interface. S2, the composite blank is subjected to low-temperature recovery annealing treatment at a temperature of 550°C and a holding time of 5 hours to obtain the recovery-treated blank; S3, the recovery treatment billet is heated to 985°C and held for 90 minutes, and then the first pass of controlled rolling is performed. The reduction rate of the first pass of controlled rolling is 35%, and the first rolled billet is obtained. S4. Within a temperature range lower than the heating temperature described in step S3, the first rolled billet is rolled in subsequent passes. The rolling temperature of each subsequent pass is controlled at 880°C, the single-pass reduction rate of each subsequent pass is 17%, and the final rolling temperature is not lower than 850°C to obtain a final rolled composite plate. S5. After rolling, the final rolled composite plate is subjected to accelerated cooling at a rate of 20°C / s. The accelerated cooling is water mist cooling, which allows the cladding layer to pass through a temperature range of 650-850°C and cool down to below 480°C. Then, it is air-cooled to room temperature to obtain a nickel-based corrosion-resistant alloy-steel composite plate. The total thickness of the obtained nickel-based corrosion-resistant alloy-steel composite plate is 130mm, and the thickness of the cladding layer is 3.5mm.

[0036] Example 4 This embodiment provides a method for preparing a nickel-based corrosion-resistant alloy-steel composite plate, including the following steps: S1. Using UNS N08825 nickel-based corrosion-resistant alloy plate as the cladding layer and SA-516 Gr.70N steel plate as the base layer, the surface of the steel base plate to be laminated is sandblasted to achieve a surface roughness Ra of 8μm. The surface of the nickel-based corrosion-resistant alloy plate to be laminated is mechanically ground to remove the surface oxide layer. After surface treatment, the cladding layer and the base layer are assembled with an open gap, and low-detonation-velocity ammonium nitrate explosive is used for explosive lamination with a detonation velocity of 2330m / s and a gap angle of 8° to obtain a composite blank with a pre-bonded interface. S2, the composite blank is subjected to low-temperature recovery annealing treatment at a temperature of 480°C and a holding time of 8 hours to obtain the recovery-treated blank; S3, the recovery treatment billet is heated to 1020°C and held for 50 minutes, and then the first pass of controlled rolling is performed. The reduction rate of the first pass of controlled rolling is 28%, and the first rolled billet is obtained. S4. Within a temperature range lower than the heating temperature described in step S3, the first rolled billet is rolled in subsequent passes. The rolling temperature of each subsequent pass is controlled at 935°C, the single-pass reduction rate of each subsequent pass is 8%, and the final rolling temperature is not lower than 850°C to obtain a final rolled composite plate. S5. After rolling, the final rolled composite plate is subjected to accelerated cooling at a rate of 30°C / s. The accelerated cooling is water mist cooling, which allows the cladding layer to pass through a temperature range of 650-850°C and cool down to below 520°C. Then, it is air-cooled to room temperature to obtain a nickel-based corrosion-resistant alloy-steel composite plate. The total thickness of the obtained nickel-based corrosion-resistant alloy-steel composite plate is 110mm, and the thickness of the cladding layer is 2.8mm.

[0037] Comparative Example 1 This comparative example provides a method for preparing a nickel-based corrosion-resistant alloy-steel composite plate. The difference from Example 1 is that the low-temperature recovery annealing treatment in S2 is not performed. Specifically, after obtaining the composite billet with a pre-bonded interface in S1, the composite billet is directly heated to 970°C and held for 70 minutes, followed by a first pass of controlled rolling with a reduction rate of 32% to obtain a first rolled billet. The remaining steps and parameters are the same as in Example 1.

[0038] Comparative Example 2 This comparative example provides a method for preparing a nickel-based corrosion-resistant alloy-steel composite plate. The difference from Example 1 is that the heating temperature in S3 is increased to 1150°C and the holding time is 70 min. Specifically, the recovery-treated billet is heated to 1150°C and held for 70 min, followed by a first pass of controlled rolling. The reduction rate of the first pass of controlled rolling is 32%, and a first rolled billet is obtained. The remaining steps and parameters are the same as in Example 1.

[0039] Comparative Example 3 This comparative example provides a method for preparing a nickel-based corrosion-resistant alloy-steel composite plate. The difference from Example 1 is that accelerated cooling is not performed in S5. Specifically, the final rolled composite plate is air-cooled to room temperature after rolling to obtain the nickel-based corrosion-resistant alloy-steel composite plate. The remaining steps and parameters are the same as in Example 1.

[0040] Comparative Example 4 This comparative example provides a method for preparing a nickel-based corrosion-resistant alloy-steel composite plate. The difference from Example 1 is that the reduction rate of the first pass of controlled rolling in S3 is reduced to 15%. Specifically, the recovery-treated billet is heated to 970°C and held for 70 minutes, followed by the first pass of controlled rolling with a reduction rate of 15% to obtain the first rolled billet. The remaining steps and parameters are the same as in Example 1.

[0041] Performance testing methods: The nickel-based corrosion-resistant alloy-steel composite plates prepared in Examples 1-4 and Comparative Examples 1-4 were subjected to room temperature tensile tests, low temperature impact tests, shear tests, intergranular corrosion tests, and pitting corrosion tests.

[0042] Tensile testing at room temperature was conducted according to ASTM A370-24a. Samples were taken along the rolling direction of the composite plate, and the specimens were machined into circular cross-section tensile specimens. Testing was performed using a computer-controlled electronic universal testing machine. During the test, the tensile strength, 0.2% yield strength, and elongation after fracture of the specimens were recorded to evaluate the overall load-bearing capacity and plasticity retention of the composite plate.

[0043] Low-temperature impact testing was conducted according to ASTM A370-24a. Samples were taken along the rolling direction of the composite plate and machined into Charpy V-notch impact specimens measuring 10 mm × 10 mm × 55 mm. The test temperature was -46 °C. After the specimens were held at the specified temperature, impact testing was performed, and the impact absorption energy was recorded to evaluate the toughness retention of the composite plate under low-temperature conditions.

[0044] Shear tests were conducted according to ASTM A265-12 (2019). Shear specimens were prepared along the thickness direction of the composite board, ensuring the interface between the cladding and the base layer was located in the shear stress zone. Before testing, the width of the shear zone and the thickness of the cladding were measured. A computer-controlled electronic universal testing machine was used to apply load until the interface shear failed. The maximum shear force was recorded, and the interfacial shear strength was calculated based on the maximum shear force and the shear area to evaluate the interfacial bonding performance between the cladding and the base layer.

[0045] The results of room temperature tensile tests, low temperature impact tests, and shear tests for the examples and comparative examples are shown in Table 1.

[0046] Intergranular corrosion testing was conducted according to ASTM G28-24 Method A. Samples were taken from the nickel-based corrosion-resistant alloy cladding side. After grinding, cleaning, drying, and weighing, the sample surface was placed in a ferric sulfate-50% sulfuric acid solution and corroded at 120°C for 120 hours. After the test, the sample was removed and sequentially rinsed with water, cleaned with alcohol, and dried, then weighed again. The intergranular corrosion rate was calculated based on the mass difference before and after corrosion, the sample surface area, material density, and corrosion time. After corrosion, the sample surface and cross-section were observed under 50x magnification to check for intergranular erosion.

[0047] Pitting corrosion tests were conducted according to ASTM G48-25 Method A. Samples were taken from the nickel-based corrosion-resistant alloy cladding side. After polishing, cleaning, drying, and weighing, the sample surface was placed in a 6% FeCl3 solution and corroded at 22°C for 24 hours. After the test, the sample was removed and subjected to the following steps in sequence: rinsing with water, brushing, rinsing with water again, ultrasonic cleaning, alcohol cleaning, and drying. The sample was weighed again, and the pitting corrosion mass loss rate was calculated based on the mass difference before and after corrosion and the sample surface area. After corrosion, the sample surface was observed under a 20x microscope to check for pitting corrosion.

[0048] The results of intergranular corrosion and pitting corrosion tests for the examples and comparative examples are shown in Table 2.

[0049] Table 1. Test results of mechanical properties and interfacial bonding properties of nickel-based corrosion-resistant alloy-steel composite plates prepared in Examples 1-4 and Comparative Examples 1-4.

[0050] Table 2. Corrosion performance test results of nickel-based corrosion-resistant alloy-steel composite plates of Examples 1-4 and Comparative Examples 1-4

[0051] Depend on Figure 1 It can be seen that after the intergranular corrosion test in Example 1, no obvious corrosion grooves extending continuously along the grain boundaries were observed on the surface of the stratum corneum, and no penetrating erosion morphology was formed in the grain boundary region; Figure 2 As can be seen, after the pitting corrosion test in Example 1, no obvious pitting pits were observed on the surface of the composite layer, and the surface morphology remained relatively continuous.

[0052] As shown in Tables 1 and 2, compared with Example 1, Comparative Example 1 showed decreased tensile strength, yield strength, elongation after fracture, low-temperature impact energy, and interfacial shear strength, and increased intergranular corrosion rate and pitting corrosion mass loss rate; Comparative Example 2 showed decreased elongation after fracture, low-temperature impact energy, and interfacial shear strength, and increased intergranular corrosion rate and pitting corrosion mass loss rate, with intergranular erosion and pitting corrosion occurring; Comparative Example 3 showed decreased tensile strength, yield strength, elongation after fracture, low-temperature impact energy, and interfacial shear strength, and increased intergranular corrosion rate and pitting corrosion mass loss rate, with intergranular erosion and pitting corrosion occurring; Comparative Example 4 showed decreased tensile strength, yield strength, elongation after fracture, low-temperature impact energy, and interfacial shear strength, and increased intergranular corrosion rate and pitting corrosion mass loss rate.

[0053] This is because Comparative Example 1 did not undergo low-temperature recovery annealing, and the residual stress, high-strain hardening zone, and localized inhomogeneous areas near the explosive composite interface were not sufficiently stabilized. During subsequent heating and rolling, localized stress concentration at the interface was more likely to cause microcrack propagation or interface slip, reducing interfacial shear strength and decreasing overall plasticity and low-temperature impact absorption energy. Comparative Example 2 increased the pre-rolling heating temperature, leading to increased element diffusion and thermal exposure in the cladding and base layers at higher temperatures. This increased the effective time of the cladding layer in the sensitization temperature zone during subsequent cooling, enhancing the tendency for grain boundary precipitation and chromium-depleted zone formation. Consequently, the intergranular corrosion rate and pitting corrosion quality loss rate increased. Simultaneously, higher heating temperatures increased the tendency for base layer microstructure coarsening, reducing low-temperature impact absorption energy.

[0054] In Comparative Example 3, no accelerated cooling was performed after rolling, resulting in a longer residence time of the cladding layer within the sensitization temperature range. This led to increased segregation of interstitial atoms towards grain boundaries and longer growth time of chromium-rich precipitates, making the chromium-depleted grain boundary regions more prone to continuity. Consequently, intergranular corrosion and pitting corrosion performance decreased. In Comparative Example 4, the reduced reduction rate in the first pass of controlled rolling resulted in insufficient compaction and extension of the pre-bonded interface. Local micropores, weak bonding areas, and wavy interface transition regions were not adequately compacted, leading to reduced interfacial shear strength and decreased plasticity and low-temperature impact energy absorption of the composite plate.

[0055] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing a nickel-based corrosion-resistant alloy-steel composite plate, characterized in that, Includes the following steps: S1, using a nickel-based corrosion-resistant alloy plate as a cladding layer and a steel base plate as a base layer, the surfaces of the cladding layer and the base layer to be composited are treated and then assembled, and explosive composite is performed to obtain a composite blank with a pre-bonded interface. S2, the composite blank is subjected to low-temperature recovery annealing treatment, the temperature of the low-temperature recovery annealing is 450-550℃, and the holding time is 4-8h, to obtain the recovery treated blank; S3, the recovered billet is heated and held at a certain temperature and then subjected to a first pass of controlled rolling. The heating temperature is 970-1020℃, the holding time is 30-90min, and the reduction rate of the first pass of controlled rolling is 25-35%, to obtain the first rolled billet. S4, within a temperature range lower than that described in S3 for heating and heat preservation, the first rolled billet is subjected to subsequent rolling passes to obtain a final rolled composite plate; S5, after rolling, the final rolled composite plate is accelerated cooled to obtain a nickel-based corrosion-resistant alloy-steel composite plate.

2. The method for preparing the nickel-based corrosion-resistant alloy-steel composite plate according to claim 1, characterized in that, In S1, the surface treatment is as follows: shot blasting or sandblasting is performed on the surface of the steel base plate to be laminated, so that the surface roughness Ra of the surface of the steel base plate to be laminated is 6-12μm; pickling or mechanical grinding is performed on the surface of the nickel-based corrosion-resistant alloy plate to be laminated, so as to remove the surface oxide layer.

3. The method for preparing the nickel-based corrosion-resistant alloy-steel composite plate according to claim 1, characterized in that, In S1, the explosive composite uses low-detonation-velocity explosives with a detonation velocity of 2000-2500 m / s and a gap angle of 8°-12°.

4. The method for preparing the nickel-based corrosion-resistant alloy-steel composite plate according to claim 1, characterized in that, In S4, the rolling temperature of subsequent passes is 880-960℃, the single-pass reduction rate is 8-22%, and the final rolling temperature is not lower than 850℃.

5. The method for preparing the nickel-based corrosion-resistant alloy-steel composite plate according to claim 1, characterized in that, In S5, the accelerated cooling rate is 15-30℃ / s. The accelerated cooling is one of water mist cooling, air mist cooling or laminar flow cooling, so that the composite layer passes through the temperature range of 650-850℃ and is cooled to below 550℃, and then air-cooled to room temperature.

6. The preparation method according to claim 1, characterized in that, The nickel-based corrosion-resistant alloy plate is any one of UNS N08825, UNS N06625, UNS N10276, and UNS N06022; the steel base plate is any one of SA-516 Gr.70N, SA-516Gr.70, Q345R, and 16MnR.

7. A nickel-based corrosion-resistant alloy-steel composite plate, characterized in that, It is prepared by any one of claims 1-6.

8. The nickel-based corrosion-resistant alloy-steel composite plate according to claim 7, characterized in that, The nickel-based corrosion-resistant alloy-steel composite plate includes a cladding layer and a base layer. The total thickness of the nickel-based corrosion-resistant alloy-steel composite plate is not less than 100 mm, and the thickness of the cladding layer is 2.5-3.5 mm.

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