Preparation method of composite board with excellent interface bonding
By performing specific surface treatment and welding processes on the substrate blank, combined with vacuuming and heat treatment steps, the problem of insufficient interfacial bonding strength of the heat-treated composite plate was solved, and the high shear strength and high toughness of the composite plate under high temperature conditions were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INST OF RES OF IRON & STEEL JIANGSU PROVINCE
- Filing Date
- 2026-04-13
- Publication Date
- 2026-05-12
AI Technical Summary
In the prior art, the interfacial bonding strength of heat-treated composite panels is insufficient under high-temperature conditions, which leads to deterioration of shear strength, increase in the width of the decarburized layer and formation of brittle and hard phases, thus affecting the performance of the composite panel.
By performing specific surface treatment and welding processes on the substrate blank, combined with vacuuming and heat treatment steps, atomic diffusion is controlled to form a metallurgical bond and avoid increasing the width of the decarburized layer. The shear strength is improved by using a wavy surface treatment and a serrated interlocking structure.
The composite board exhibits excellent interfacial bonding under high-temperature conditions, increased shear strength, reduced decarburized layer width, and decreased interfacial hardness, thus meeting the performance requirements of high strength and high toughness.
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Abstract
Description
Technical Field
[0001] This application relates to the field of composite board preparation technology, and in particular to a method for preparing a composite board with excellent interfacial bonding. Background Technology
[0002] Currently, composite panels prepared by hot rolling exhibit excellent shear strength, generally reaching 210 MPa, and some even exceeding 300 MPa. However, for heat-treated composite panels, atoms continue to diffuse during high-temperature insulation, leading to two key changes: first, the width of the decarburized layer increases. The decarburized layer is a weak bonding area; the wider the decarburized layer, the more prone the composite panel is to cracking at this point. Second, the interfacial hardness increases. The presence of a brittle-hard phase at the bonding interface causes a sudden increase in hardness, and this brittle-hard phase has a significant adverse effect on shear strength. These two changes ultimately severely deteriorate the shear strength of the composite panel. Summary of the Invention
[0003] The purpose of this application is to provide a method for preparing a composite plate with excellent interfacial bonding, which solves the problem that the interfacial bonding strength under high temperature conditions in the prior art does not meet the requirements for use.
[0004] To achieve one of the aforementioned objectives, one embodiment of this application provides a method for preparing a composite plate with excellent interfacial bonding, comprising the following sequential processes: billet surface treatment, billet assembly and sealing, welding, vacuuming, heating, rolling, cooling, heat treatment, and plate separation.
[0005] In the surface treatment step, if the processing and use temperature of the composite board is ≤200℃, then the surface of one side of the substrate blank is ground until the roughness Ra satisfies: 0.02T+0.05t+0.5CR-5≤Ra≤0.02T+0.05t+0.5CR, where T is the preset heat treatment temperature in ℃, t is the total heat treatment time in min, and CR is the preset total compression ratio. If multiple heat treatments are required, T is the highest value of the multiple preset heat treatment temperatures. If the processing and use temperature of the composite board is >200℃, then one side of the substrate blank should be polished into a wavy shape. The vertical distance λ1 between the crest and trough of the wave satisfies: 0.1T-85≤λ1≤0.1T-80, in mm. The horizontal distance λ2 between the crests satisfies: 100-12.5lnT≤λ2≤110-12.5lnT, in cm. The vertical direction is the thickness direction of the substrate blank, and the horizontal direction is perpendicular to the vertical direction and consistent with the direction of wave extension.
[0006] In one embodiment of this application, in the surface treatment step, the two sides of the cladding blank are ground until the surface roughness Ra of the blank is ≤1μm, and then placed in the order of substrate-cladding-cladding-substrate to obtain a composite blank; In the blank assembly and sealing step, four edge strips are placed around the cover material blank. The edge strips are made of the same material as the base material. The inner side of the edge strips is tightly attached to the cover material, and vacuum holes are opened on the edge strips. In the welding step, the edge strip is welded to the base material blank. The welding process is as follows: welding wire extension length: 15~20mm; welding current: 300~750A; welding voltage: 20~50V; welding speed: 300~500mm / min.
[0007] In one embodiment of this application, the temperature is preheated to 180~220°C before welding, the interpass temperature is controlled to 100~180°C during welding, and the temperature is allowed to cool naturally to room temperature after welding.
[0008] In one embodiment of this application, during the vacuuming step, after welding is completed, the cavity between the four edge strips and the two substrate blanks is evacuated through a vacuum hole until the pressure is ≤10. -4 Torr, holding time is 2V~4V, unit is h, V is the total volume of the two-layer cladding blank, unit is m. 3 After the pressure holding period is completed, seal the vacuum hole.
[0009] In one embodiment of this application, in the heat treatment step, the composite plate obtained after rolling and cooling is subjected to normalizing, normalizing with water cooling, normalizing with water cooling combined with tempering, or quenching combined with tempering for heat treatment, wherein... In normalizing heat treatment, the normalizing temperature is T. N +30~T N +50℃, the final cooling temperature for normalizing water cooling is T NC +100~T NC +150℃; In quenching heat treatment, the quenching temperature is T. N +30~T N +50℃, In tempering heat treatment, the tempering temperature is T. T -10~T T +10℃, T N =900-203 -15[Ni]-45[Si]+104[V]+31.5[Mo]+t f , T NC =650-423[C]-30[Mn]-20[Si]-12[Cr]-18[Ni]-7[Mo]-t f , T T=700-0.16H+7CE, CE=[C]+[Mn] / 6+([Cr]+[Mo]+[V]) / 5+[Ni] / 15, where [C], [Mn], [Si], [Cr], [Ni], [Mo], and [V] are 100 times the mass percentage of the corresponding elements in the substrate, t f H represents the thickness of the composite panel in mm, and H represents the maximum Brinell hardness required for the strength grade of the base steel plate in the composite panel.
[0010] In one embodiment of this application, the holding coefficient for normalizing and quenching heat treatment is 1.5~1.7 min / mm, and the holding coefficient for tempering is 2.8~3.2 min / mm.
[0011] In one embodiment of this application, the chemical composition of the substrate blank, by mass percentage, includes: C: 0.10~0.20%, Si: 0.15~0.35%, Mn: 0.6~1.7%, Cr≤0.30%, Ni≤0.30%, Mo≤0.20%, Nb≤0.030%, Ti≤0.03%, Al: 0.02~0.06%, V≤0.040%, P≤0.020%, S≤0.005%, CE: 0.22~0.50%, with the remainder being iron and unavoidable impurities. CE = [C] + [Mn] / 6 + ([Cr] + [Mo] + [V]) / 5 + [Ni] / 15, where [C], [Mn], [Cr], [Mo], [V], and [Ni] are each 100 times the mass percentage of the corresponding element in the substrate blank.
[0012] In one embodiment of this application, the chemical composition of the substrate blank, by mass percentage, includes: C: 0.14~0.17%, Si: 0.15~0.25%, Mn: 0.60~1.00%, Nb≤0.020%, Cr≤0.30%, Ti≤0.030%, Al: 0.020~0.050%, P≤0.020%, S≤0.005%, CE: 0.22~0.32%, with the remainder being iron and unavoidable impurities; In the welding step, the edge strip is welded to the base material blank. The welding process is as follows: welding wire extension length: 15~20mm; welding current: 300~500A; welding voltage: 20~40V; welding speed: 300~400mm / min.
[0013] In one embodiment of this application, the chemical composition of the substrate blank, by mass percentage, includes: C: 0.14~0.18%, Si: 0.15~0.25%, Mn: 1.30~1.60%, Nb≤0.030%, Ti: 0.010~0.020%, Al: 0.020~0.050%, P≤0.015%, S≤0.005%, CE: 0.35~0.50%, with the remainder being iron and unavoidable impurities; In the welding step, the edge strip is welded to the base material blank. The welding process is as follows: welding wire extension length: 15~20mm; welding current: 400~600A; welding voltage: 25~45V; welding speed: 300~450mm / min.
[0014] In one embodiment of this application, the chemical composition of the substrate blank, by mass percentage, includes: C: 0.14~0.20%, Si: 0.25~0.35%, Mn: 1.30~1.60%, Nb: 0.015~0.030%, Cr: 0.10~0.20%, Ti: 0.010~0.020%, V≤0.020%, Al: 0.020~0.060%, P≤0.013%, S≤0.003%, CE: 0.40~0.45%, with the remainder being iron and unavoidable impurities; In the welding step, the edge strip is welded to the base material blank. The welding process is as follows: welding wire extension length: 15~20mm; welding current: 500~700A; welding voltage: 30~50V; welding speed: 300~500mm / min.
[0015] In one embodiment of this application, the chemical composition of the substrate blank, by mass percentage, includes: C: 0.10~0.15%, Si: 0.15~0.35%, Mn: 1.10~1.70%, Nb≤0.02%, Cr: 0.10~0.20%, Ti≤0.030%, V≤0.040%, Ni: 0.10~0.30%, Mo≤0.20%, Al: 0.020~0.060%, P≤0.013%, S≤0.003%, CE: 0.30~0.50%, with the remainder being iron and unavoidable impurities; In the welding step, the edge strip is welded to the base material blank. The welding process is as follows: welding wire extension length: 15~20mm; welding current: 550~750A; welding voltage: 35~50V; welding speed: 300~500mm / min.
[0016] One or more technical solutions provided in this application have at least the following technical effects or advantages: In the method for preparing a composite plate with excellent interfacial bonding provided in this application, the surface of one side of the substrate is treated differently according to the processing and usage temperature of the composite plate. When the processing and usage temperature is low, the roughness is limited, and the pores formed at the bonding interface during rolling prevent atomic diffusion. During heat treatment, atoms continue to diffuse across the pores, achieving metallurgical bonding while avoiding an increase in the width of the local decarburized layer at the bonding interface. When the processing and usage temperature is high, the substrate surface is wavy, which allows for inconsistent diffusion of C and Cr atoms at different locations. The weak bonding areas are not on the same horizontal line, forming a serrated interlocking, which increases the shear strength. Detailed Implementation
[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0018] This application provides a method for preparing a composite plate with excellent interface bonding, including a sequential process of billet surface treatment, billet assembly and sealing, welding, vacuuming, heating, rolling, cooling, heat treatment, and plate separation. In the surface treatment step, if the processing and use temperature of the composite board is ≤200℃, the surface of one side of the substrate blank shall be ground until the roughness Ra satisfies: 0.02T+0.05t+0.5CR-5≤Ra≤0.02T+0.05t+0.5CR, where T is the preset heat treatment temperature in ℃, t is the total heat treatment time in min, and CR is the preset total compression ratio. If multiple heat treatments are required, T shall be the highest value of the multiple preset heat treatment temperatures. If the processing and use temperature of the composite board is >200℃, then one side of the substrate blank should be polished into a wavy shape. The vertical distance λ1 between the crest and trough of the wave satisfies: 0.1T-85≤λ1≤0.1T-80, in mm. The horizontal distance λ2 between the crests satisfies: 100-12.5lnT≤λ2≤110-12.5lnT, in cm. The vertical direction is the thickness direction of the substrate blank, and the horizontal direction is perpendicular to the vertical direction and consistent with the direction of wave extension.
[0019] The width of the decarburized layer at the interface of the composite board increases with the increase of heat treatment temperature and the extension of heat preservation time. The decarburized layer is a weak bond area, which will affect the shear strength of the composite board.
[0020] When the surface roughness Ra is limited to 0.02T+0.05t+0.5CR-5≤Ra≤0.02T+0.05t+0.5CR, the pores formed at the bonding interface during rolling prevent atomic diffusion. During heat treatment, atoms continue to diffuse across the pores, achieving metallurgical bonding while avoiding an increase in the width of the local decarburized layer at the bonding interface. Compared to existing technologies, the weak bonding area is reduced after heat treatment (the decarburized layer width is narrower, and the interface hardness is reduced), while the shear strength is increased.
[0021] After processing and forming, composite panels undergo multiple heat treatments and are used under high-temperature conditions. As the heat treatment time increases and the operating temperature rises, atoms such as C, Cr, and Ni continue to diffuse and form brittle and hard carbides at the bonding interface. Surface roughening processes are no longer sufficient to meet the requirements. By using a wavy shape for the substrate blank, the diffusion of C and Cr atoms at different locations becomes uneven, and the weak bonding areas are not on the same horizontal line, forming a serrated interlocking structure, which increases shear strength.
[0022] In some embodiments of this application, in the surface treatment step, the two sides of the cladding blank are ground until the surface roughness Ra of the blank is ≤1μm, and then placed in the order of substrate-cladding-cladding-substrate to obtain a composite blank.
[0023] The two sides of the cladding blank are in contact with the base material blank and another cladding blank, respectively, and both sides need to be ground. The cladding blank is ground until both sides show a fresh metallic luster. The low surface roughness of the cladding blank is conducive to atomic diffusion and makes it easier to achieve metallurgical bonding with the base material blank.
[0024] In the blank assembly and sealing step, four edge strips are placed around the cover material blank. The edge strips are made of the same material as the base material. The inner side of the edge strips is tightly attached to the cover material, and vacuum holes are opened on the edge strips. In the welding process, the edge strip is welded to the base material blank. The welding process is as follows: welding wire extension length: 15~20mm; welding current: 300~750A; welding voltage: 20~50V; welding speed: 300~500mm / min.
[0025] By controlling the welding process, an excellent bond is achieved between the substrate and the edge strip, preventing cracking during rolling and ensuring that the vacuum between the substrate and the edge strip is maintained, thus affecting the bond between the substrate and the cladding.
[0026] Two elliptical vacuum holes are made on the edge strip at the midpoint of the composite billet's width direction. Hole 1 is located at 1 / 3 of the width and 1 / 2 of the height at the head of the composite billet, and hole 2 is located at 2 / 3 of the width and 1 / 2 of the height at the tail of the composite billet. The height of the vacuum holes is (0.05~0.07)t. b , t bThe thickness of the composite billet is in mm, and the width of the vacuum hole is (0.015~0.03)w, where w is the width of the composite billet. Insert the vacuum tube into the vacuum hole to prepare for vacuuming.
[0027] In some embodiments of this application, preheating is performed at 180~220°C before welding, and the interpass temperature is controlled at 100~180°C during welding. After welding, the material is allowed to cool naturally to room temperature. Preheating can effectively prevent the generation of welding cold cracks and avoid insufficient vacuum. Maintaining the interpass temperature during welding can ensure weld quality and prevent the generation of welding cold cracks.
[0028] In some embodiments of this application, during the vacuuming step, after welding is completed, the cavity between the four edge strips and the two substrate blanks is evacuated through a vacuum hole until the pressure is ≤10. -4 Torr, holding time is 2V~4V, unit is h, V is the total volume of the two-layer cladding blank, unit is m. 3 After the pressure holding period is over, seal the vacuum hole.
[0029] The cavity formed between the edge strip and the substrate blank maintains a high vacuum, resulting in fewer interface impurities between the substrate and the cladding, which is beneficial for the interfacial bonding between the substrate and the cladding.
[0030] During the heating process, the heating temperature of the composite billet is controlled at 1170~1200℃, and the total furnace time is ≥1.1t. b The unit is min, t b The total thickness of the composite blank is expressed in mm.
[0031] In the rolling process, the initial rolling temperature for roughing is 1020~1080℃, and the initial rolling temperature for finishing is Ts-5~Ts+5, where Ts=Tr+200 / t f The final rolling temperature is Tr-10 to Tr+10, where Tr = 910-200. +50[Si]-30[Mn]-20[Ni]+70[P]+40[V]-10[Cr]-a×t f The unit is ℃, where a is 1~2, and t f The thickness of the composite panel is in mm.
[0032] In the cooling process, the final cooling temperature is Tc-20~Tc+20, where Tc = 680-20[Mn]+30[Si]-15[Ni]-b×t f The unit is ℃, where b is 1~2, and t f The thickness of the composite panel is in mm.
[0033] In some embodiments of this application, during the heat treatment step, the composite plate obtained after rolling and cooling is subjected to normalizing, normalizing with water cooling, normalizing with water cooling combined with tempering, or quenching combined with tempering for heat treatment. In normalizing heat treatment, the normalizing temperature is T. N +30~T N +50℃, the final cooling temperature for normalizing water cooling is T NC +100~T NC +150℃; In quenching heat treatment, the quenching temperature is T. N +30~T N +50℃, In tempering heat treatment, the tempering temperature is T. T -10~T T +10℃, T N =900-203 -15[Ni]-45[Si]+104[V]+31.5[Mo]+t f , T NC =650-423[C]-30[Mn]-20[Si]-12[Cr]-18[Ni]-7[Mo]-t f , T T =700-0.16H+7CE, CE=[C]+[Mn] / 6+([Cr]+[Mo]+[V]) / 5+[Ni] / 15, where [C], [Mn], [Si], [Cr], [Ni], [Mo], and [V] are 100 times the mass percentage of the corresponding elements in the substrate, t f H represents the thickness of the composite panel in mm, and H represents the maximum Brinell hardness required for the strength grade of the base steel plate in the composite panel.
[0034] Depending on the chemical composition of the base material, different heat treatments can be applied to the composite plate obtained after rolling and cooling. These include normalizing heat treatment only, water cooling after normalizing heat treatment, tempering heat treatment after normalizing and water cooling, and tempering heat treatment after quenching.
[0035] For lower-strength composite plates, normalizing can shorten the production process and reduce production costs. For high-strength composite plates, normalizing with water cooling and tempering or quenching and tempering can refine the grains and suppress the precipitation of brittle phases, thereby meeting the performance requirements of high strength, high toughness, and easy welding.
[0036] Excessive normalizing temperature leads to coarse grains, which is detrimental to toughness; insufficient normalizing temperature cannot completely eliminate rolling defects and results in uneven steel plate structure, affecting mechanical properties.
[0037] The selection of normalizing and final cooling temperatures can ensure uniform microstructure, eliminate rolling defects, and guarantee the strength and toughness of the composite plate. Higher normalizing and final cooling temperatures result in insufficient phase transformation of the base steel plate, leaving austenite residue and easily forming coarse lamellar pearlite, leading to uneven microstructure and lower plate strength. Lower final cooling temperatures, on the other hand, result in martensite formation, leading to decreased toughness.
[0038] In some embodiments of this application, the holding coefficient for normalizing and quenching heat treatment is 1.5~1.7 min / mm, and the holding coefficient for tempering is 2.8~3.2 min / mm. Here, mm refers to the thickness of the composite plate.
[0039] In the slab separation process, the composite board is subjected to heated straightening treatment at a temperature >200℃, and then straightened again after being left for 24 hours.
[0040] Warm straightening ensures the flatness of the resulting composite plate, reduces internal stress, and prevents edge cracking during straightening. After 24 hours, some residual stress is released, allowing for re-straightening to maintain the shape of the finished composite plate and further reduce internal stress. This prevents the composite plate from springing apart due to excessive internal stress during separation, thus avoiding safety accidents.
[0041] Plasma cutting is used for plate separation. First, the plate is cut along its length, then the tail section is cut laterally, and finally the head section is cut laterally. This cutting sequence maximizes the release of internal stress. Placing the head section, which has the lowest stress, for the last cut prevents stress separation in the steel plate and avoids accidents.
[0042] The composite panels obtained after separation are straightened, finished, water-polished, and subjected to flaw detection.
[0043] In some embodiments of this application, the chemical composition of the substrate blank, by mass percentage, includes: C: 0.10~0.20%, Si: 0.15~0.35%, Mn: 0.6~1.7%, Cr≤0.30%, Ni≤0.30%, Mo≤0.20%, Nb≤0.030%, Ti≤0.03%, Al: 0.02~0.06%, V≤0.040%, P≤0.020%, S≤0.005%, CE: 0.22~0.50%, with the remainder being iron and unavoidable impurities. CE = [C] + [Mn] / 6 + ([Cr] + [Mo] + [V]) / 5 + [Ni] / 15, where [C], [Mn], [Cr], [Mo], [V], and [Ni] are 100 times the mass percentage of the corresponding element in the substrate blank.
[0044] The composite plate prepared based on the aforementioned chemical composition of the substrate and the aforementioned process method achieves an area bonding rate of 100% and a shear strength ≥300MPa; the residual stress distribution of the entire plate is uniform, with the highest residual stress ≤120MPa; the steel plate has good shape, with an unevenness ≤2mm / m; it has excellent resistance to intergranular corrosion and can meet the requirements of various corrosion conditions; it does not crack after 180° inward bending, 180° lateral bending, and 180° outward bending; the yield strength is ≥245MPa, the tensile strength is 400~700MPa, the impact at -20℃ is ≥90J, and the Brinell hardness is ≤240HBW.
[0045] The following describes different welding and heat treatment processes based on substrates of different strength levels: For a 245MPa grade substrate, the welding process is as follows: wire extension length: 15~20mm; welding current: 300~500A; welding voltage: 20~40V; welding speed: 300~400mm / min.
[0046] The chemical composition of the substrate blank, by mass percentage, includes: C: 0.14~0.17%, Si: 0.15~0.25%, Mn: 0.60~1.00%, Nb≤0.020%, Cr≤0.30%, Ti≤0.030%, Al: 0.020~0.050%, P≤0.020%, S≤0.005%, CE: 0.22~0.32%, with the remainder being iron and unavoidable impurities.
[0047] Furthermore, when the substrate has a strength of 245 MPa, normalizing heat treatment is used, with a normalizing heat retention coefficient of 1.5~1.7 min / mm.
[0048] The composite plate made by the aforementioned process of 245MPa grade substrate and cladding material has an area bonding rate of 100%, shear strength ≥400MPa; uniform residual stress distribution throughout the plate, with the highest residual stress ≤80MPa; steel plate unevenness ≤2mm / m; excellent resistance to intergranular corrosion, meeting the requirements of various corrosion conditions; no cracking after 180° inward bending, 180° lateral bending, and 180° outward bending; yield strength ≥245MPa, tensile strength 400~520MPa, impact at -20℃ ≥90J, and Brinell hardness ≤140HBW.
[0049] For a 345MPa grade substrate, the welding process is as follows: wire extension length: 15~20mm; welding current: 400~600A; welding voltage: 25~45V; welding speed: 300~450mm / min.
[0050] The chemical composition of the substrate blank, by mass percentage, includes: C: 0.14~0.18%, Si: 0.15~0.25%, Mn: 1.30~1.60%, Nb≤0.030%, Ti: 0.010~0.020%, Al: 0.020~0.050%, P≤0.015%, S≤0.005%, CE: 0.35~0.50%, with the remainder being iron and unavoidable impurities.
[0051] Furthermore, when the substrate has a strength of 345MPa, normalizing water-cooling heat treatment is adopted, and the normalizing heat preservation coefficient is 1.5~1.7min / mm.
[0052] The composite plate made by the aforementioned process of 345MPa grade substrate and cladding material has a 100% area bonding rate and a shear strength ≥380MPa; the residual stress distribution of the whole plate is uniform, with the highest residual stress ≤100MPa; the flatness of the steel plate is ≤2mm / m; it has excellent resistance to intergranular corrosion and can meet the requirements of various corrosion conditions; it does not crack after 180° inward bending, 180° lateral bending, and 180° outward bending; the yield strength is ≥345MPa, the tensile strength is 450~600MPa, the impact at -20℃ is ≥90J, and the Brinell hardness is ≤170HBW.
[0053] For a 370MPa grade substrate, the welding process is as follows: wire extension length: 15~20mm; welding current: 500~700A; welding voltage: 30~50V; welding speed: 300~500mm / min.
[0054] The chemical composition of the substrate blank, by mass percentage, includes: C: 0.14~0.20%, Si: 0.25~0.35%, Mn: 1.30~1.60%, Nb: 0.015~0.030%, Cr: 0.10~0.20%, Ti: 0.010~0.020%, V≤0.020%, Al: 0.020~0.060%, P≤0.013%, S≤0.003%, CE: 0.40~0.45%, with the remainder being iron and unavoidable impurities.
[0055] Furthermore, when the substrate has a strength of 370MPa, heat treatment is carried out by normalizing and water cooling combined with tempering. The normalizing heat preservation coefficient is 1.5~1.7min / mm, and the tempering heat preservation coefficient is 2.8~3.2min / mm.
[0056] The composite plate made by the aforementioned process of 370MPa grade substrate and cladding material has a 100% area bonding rate and a shear strength ≥370MPa; the residual stress distribution of the whole plate is uniform, with the highest residual stress ≤100MPa; the flatness of the steel plate is ≤2mm / m; it has excellent resistance to intergranular corrosion and can meet the requirements of various corrosion conditions; it does not crack after 180° inward bending, 180° lateral bending, and 180° outward bending; the yield strength is ≥370MPa, the tensile strength is 500~650MPa, the impact at -20℃ is ≥90J, and the Brinell hardness is ≤200HBW.
[0057] For a 420MPa grade substrate, the welding process is as follows: wire extension length: 15~20mm; welding current: 550~750A; welding voltage: 35~50V; welding speed: 300~500mm / min.
[0058] The chemical composition of the substrate blank, by mass percentage, includes: C: 0.10~0.15%, Si: 0.15~0.35%, Mn: 1.10~1.70%, Nb≤0.02%, Cr: 0.10~0.20%, Ti≤0.030%, V≤0.040%, Ni: 0.10~0.30%, Mo≤0.20%, Al: 0.020~0.060%, P≤0.013%, S≤0.003%, CE: 0.30~0.50%, with the remainder being iron and unavoidable impurities.
[0059] Furthermore, when the substrate has a strength of 420MPa, heat treatment is carried out by quenching and tempering, with a quenching holding coefficient of 1.5~1.7min / mm and a tempering holding coefficient of 2.8~3.2min / mm.
[0060] The composite plate made by the aforementioned process of 420MPa grade substrate and cladding material has a 100% area bonding rate and a shear strength ≥370MPa; the residual stress distribution of the whole plate is uniform, with the highest residual stress ≤120MPa; the flatness of the steel plate is ≤2mm / m; it has excellent resistance to intergranular corrosion and can meet the requirements of various corrosion conditions; it does not crack after 180° inward bending, 180° lateral bending, and 180° outward bending; the yield strength is ≥420MPa, the tensile strength is 550~700MPa, the impact at -20℃ is ≥90J, and the Brinell hardness is ≤240HBW.
[0061] By applying different heat treatments and welding processes to substrates with different alloy contents, it is possible to ensure good interfacial bonding between the substrate and the cladding material, while also enabling the composite board to have high strength and high toughness.
[0062] The technical solution of this application will be further described below with reference to some specific embodiments.
[0063] Table 1. Chemical composition of the substrate (%)
[0064] Note: The CE results in Table 1 do not include %.
[0065] Table 2. Blanking process
[0066] Table 3 Welding Process
[0067] Table 4 Rolling process
[0068] Table 5 Heat Treatment Process
[0069] Table 6 Composite Panel Performance
[0070] The aforementioned composite panel performance was tested according to the requirements of GB / T6396 and GB / T8165, specifically: shear strength was tested by shear test; residual stress was tested by drilling method, with specific operation methods in accordance with GB / T 31310; flatness was tested by straightedge + feeler gauge method (GB / T 709-2019); cold bending test was conducted by bending test, with sample preparation and testing methods in accordance with GB / T232; tensile test was conducted on the full thickness of the composite panel, with sample preparation and testing in accordance with GB / T228; impact test required the removal of the cladding material, retaining only the substrate, with sample size, processing, and testing methods in accordance with GB / T229; hardness was the substrate hardness, tested on the substrate cross-section using a Brinell hardness tester.
[0071] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
[0072] The detailed descriptions listed above are merely specific descriptions of feasible implementation methods of this application and are not intended to limit the scope of protection of this application. All equivalent implementation methods or modifications made without departing from the spirit of the art of this application should be included within the scope of protection of this application.
Claims
1. A method for preparing a composite plate with excellent interfacial bonding, characterized in that, The method includes a sequential process of billet surface treatment, billet assembly and sealing, welding, vacuuming, heating, rolling, cooling, heat treatment, and plate separation. In the surface treatment step, if the processing and use temperature of the composite board is ≤200℃, then the surface of one side of the substrate blank is ground until the roughness Ra satisfies: 0.02T+0.05t+0.5CR-5≤Ra≤0.02T+0.05t+0.5CR, where T is the preset heat treatment temperature in ℃, t is the total heat treatment time in min, and CR is the preset total compression ratio. If multiple heat treatments are required, T is the highest value of the multiple preset heat treatment temperatures. If the processing and use temperature of the composite board is >200℃, then one side of the substrate blank should be polished into a wavy shape. The vertical distance λ1 between the crest and trough of the wave satisfies: 0.1T-85≤λ1≤0.1T-80, in mm. The horizontal distance λ2 between the crests satisfies: 100-12.5lnT≤λ2≤110-12.5lnT, in cm. The vertical direction is the thickness direction of the substrate blank, and the horizontal direction is perpendicular to the vertical direction and consistent with the direction of wave extension.
2. The method for preparing a composite plate with excellent interfacial bonding according to claim 1, characterized in that, In the surface treatment step, the two sides of the cladding blank are ground until the surface roughness Ra of the blank is ≤1μm, and then placed in the order of substrate-cladding-cladding-substrate to obtain a composite blank; In the blank assembly and sealing step, four edge strips are placed around the cover material blank. The edge strips are made of the same material as the base material. The inner side of the edge strips is tightly attached to the cover material, and vacuum holes are opened on the edge strips. In the welding step, the edge strip is welded to the base material blank. The welding process is as follows: welding wire extension length: 15~20mm; welding current: 300~750A; welding voltage: 20~50V; welding speed: 300~500mm / min.
3. The method for preparing a composite plate with excellent interfacial bonding according to claim 2, characterized in that, Preheat the sample to 180~220℃ before welding. Control the interpass temperature to 100~180℃ during welding. Allow the sample to cool naturally to room temperature after welding.
4. The method for preparing a composite plate with excellent interfacial bonding according to claim 2, characterized in that, During the vacuuming process, after welding is completed, the cavity between the four welded edge strips and the two base material blanks is evacuated through the vacuum port until the pressure is ≤10. -4 Torr, holding time is 2V~4V, unit is h, V is the total volume of the two-layer cladding blank, unit is m. 3 After the pressure holding period is completed, seal the vacuum hole.
5. The method for preparing a composite plate with excellent interfacial bonding according to claim 1, characterized in that, In the heat treatment process, the composite plate obtained after rolling and cooling is subjected to normalizing, normalizing with water cooling, normalizing with water cooling combined with tempering, or quenching combined with tempering. In normalizing heat treatment, the normalizing temperature is T. N +30~T N +50℃, the final cooling temperature for normalizing water cooling is T NC +100~T NC +150℃; In quenching heat treatment, the quenching temperature is T. N +30~T N +50℃, In tempering heat treatment, the tempering temperature is T. T -10~T T +10℃, T N =900-203 -15[Ni]-45[Si]+104[V]+31.5[Mo]+t f , T NC =650-423[C]-30[Mn]-20[Si]-12[Cr]-18[Ni]-7[Mo]-t f , T T =700-0.16H+7CE, CE=[C]+[Mn] / 6+([Cr]+[Mo]+[V]) / 5+[Ni] / 15, where [C], [Mn], [Si], [Cr], [Ni], [Mo], and [V] are 100 times the mass percentage of the corresponding elements in the substrate, t f H represents the thickness of the composite panel in mm, and H represents the maximum Brinell hardness required for the strength grade of the base steel plate in the composite panel.
6. The method for preparing a composite plate with excellent interfacial bonding according to claim 5, characterized in that, The holding coefficient for normalizing and quenching heat treatment is 1.5~1.7 min / mm, and the holding coefficient for tempering is 2.8~3.2 min / mm.
7. The method for preparing a composite plate with excellent interfacial bonding according to claim 2, characterized in that, The chemical composition of the substrate blank, by mass percentage, includes: C: 0.10~0.20%, Si: 0.15~0.35%, Mn: 0.6~1.7%, Cr≤0.30%, Ni≤0.30%, Mo≤0.20%, Nb≤0.030%, Ti≤0.03%, Al: 0.02~0.060%, V≤0.040%, P≤0.020%, S≤0.005%, CE: 0.22~0.50%, with the remainder being iron and unavoidable impurities. CE = [C] + [Mn] / 6 + ([Cr] + [Mo] + [V]) / 5 + [Ni] / 15, where [C], [Mn], [Cr], [Mo], [V], and [Ni] are each 100 times the mass percentage of the corresponding element in the substrate blank.
8. The method for preparing a composite plate with excellent interfacial bonding according to claim 7, characterized in that, The chemical composition of the substrate blank, by mass percentage, includes: C: 0.14~0.17%, Si: 0.15~0.25%, Mn: 0.60~1.00%, Nb≤0.020%, Cr≤0.30%, Ti≤0.030%, Al: 0.020~0.050%, P≤0.020%, S≤0.005%, CE: 0.22~0.32%, with the remainder being iron and unavoidable impurities; In the welding step, the edge strip is welded to the base material blank. The welding process is as follows: welding wire extension length: 15~20mm; welding current: 300~500A; welding voltage: 20~40V; welding speed: 300~400mm / min.
9. The method for preparing a composite plate with excellent interfacial bonding according to claim 7, characterized in that, The chemical composition of the substrate blank, by mass percentage, includes: C: 0.14~0.18%, Si: 0.15~0.25%, Mn: 1.30~1.60%, Nb≤0.030%, Ti: 0.010~0.020%, Al: 0.020~0.050%, P≤0.015%, S≤0.005%, CE: 0.35~0.50%, with the remainder being iron and unavoidable impurities; In the welding step, the edge strip is welded to the base material blank. The welding process is as follows: welding wire extension length: 15~20mm; welding current: 400~600A; welding voltage: 25~45V; welding speed: 300~450mm / min.
10. The method for preparing a composite plate with excellent interfacial bonding according to claim 7, characterized in that, The chemical composition of the substrate blank, by mass percentage, includes: C: 0.14~0.20%, Si: 0.25~0.35%, Mn: 1.30~1.60%, Nb: 0.015~0.030%, Cr: 0.10~0.20%, Ti: 0.010~0.020%, V≤0.020%, Al: 0.020~0.060%, P≤0.013%, S≤0.003%, CE: 0.40~0.45%, with the remainder being iron and unavoidable impurities; In the welding step, the edge strip is welded to the base material blank. The welding process is as follows: welding wire extension length: 15~20mm; welding current: 500~700A; welding voltage: 30~50V; welding speed: 300~500mm / min.
11. The method for preparing a composite plate with excellent interfacial bonding according to claim 7, characterized in that, The chemical composition of the substrate blank, by mass percentage, includes: C: 0.10~0.15%, Si: 0.15~0.35%, Mn: 1.10~1.70%, Nb≤0.02%, Cr: 0.10~0.20%, Ti≤0.030%, V≤0.040%, Ni: 0.10~0.30%, Mo≤0.20%, Al: 0.020~0.060%, P≤0.013%, S≤0.003%, CE: 0.30~0.50%, with the remainder being iron and unavoidable impurities; In the welding step, the edge strip is welded to the base material blank. The welding process is as follows: welding wire extension length: 15~20mm; welding current: 550~750A; welding voltage: 35~50V; welding speed: 300~500mm / min.