CN112848552B - Copper-steel solid-liquid composite bimetallic material for ocean engineering and preparation method thereof - Google Patents

Abstract

The invention provides a copper-steel solid-liquid composite bimetallic material for marine engineering and a preparation method thereof. In the bimetallic composite material, the base plate is a steel plate, and the copper alloy plate is attached to the surface of the steel plate; The ratio is 1:(5.6-11.2), and the preparation method includes steel plate pretreatment, preheating, solid-liquid composite, composite slab heating, hot rolling, straightening, and heat treatment; the copper-steel bimetallic composite material produced by applying the present invention, The material has a cross-section Vickers hardness of 192-208HV, the cross-section hardness difference is less than or equal to 16HV, the Z-direction tensile strength Rm≥440MPa, the elongation A≥25%, the composite interface shear strength is 240-260MPa, and the bending test is all qualified , and has good seawater corrosion resistance.

Description

Copper-steel solid-liquid composite bimetallic material for marine engineering and preparation method thereof

technical field

The invention belongs to the field of metal material production, in particular to a copper-steel solid-liquid composite bimetallic material for marine engineering and a preparation method thereof.

Background technique

The ocean is the most corrosive environment, which is a complex composed of 3% NaCl seawater + dissolved gas + suspended solids + organic matter + organisms. Among many materials, carbon steel has poor seawater corrosion resistance, and stainless steel will have crevice, stress, and pitting corrosion; among metal materials, copper alloys have excellent seawater corrosion resistance and oxidation resistance, but the cost is high. Therefore, the development of copper-steel composite materials can not only give play to the performance advantages of their respective component materials, but also realize the complementary performance advantages of each component material, meet the performance requirements that cannot be achieved by a single metal material, and save precious metal materials. High economic and social benefits.

Some experts and scholars at home and abroad are committed to the research of copper-steel bimetals, on the one hand to reduce the use of precious metal Cu, on the other hand to improve the performance of composite materials.

In the technical solution provided in the invention "bismuth bronze-steel composite bimetal bearing material and its manufacturing method" with application number 200910044854.9, the material base layer is made of carbon steel, the surface layer is a bismuth bronze alloy, and the bismuth bronze alloy is sintered in carbon Plain steel surface. The bismuth bronze alloy is sintered on the surface of the carbon steel material using the principle of powder metallurgy sintering. The disadvantage is that the sintered bimetallic composite has large porosity, poor mechanical properties, poor bearing capacity and impact resistance, and short service life.

In the technical scheme disclosed in the invention "a copper-steel composite material and its preparation method" with the application number of 200910162920.2, the chemical composition weight ratio of the composite material is: Cu 10%-15%, steel 85%-90%, and its structure is copper Composite with steel. After surface treatment, copper and steel strips are cold-rolled into high-precision steel strips and high-precision copper strips; after surface cleaning, surface residues are removed, degreased, and rolled into high-precision copper-steel composites by cold rolling mill. strips and annealed. The disadvantage is that the method of cold rolling and rolling compound has low production efficiency and low success rate, and the product is easy to be delaminated.

The invention with application number 01107029.3 "Isothermal Welding Method for the Production of Copper-Steel Composite Materials" firstly adds the protective agent into the gap between the steel mandrel and the outer wall of the composite blank without the steel mandrel, and then adds the electrolytic copper into the hopper of the composite blank; Put the charged composite billet into the well-heated electric furnace and heat it to 1130-1150°C. After all the electrolytic copper is melted, the electric furnace is cut off section by section from the bottom, so that the composite billet is cooled sequentially from the bottom to the top. The disadvantage is that the production of bimetallic composite materials is limited by production equipment, limited in size, and cannot be mass-produced.

The invention with the application number of 200910306947.4, "Induction Casting and Joining Method of Copper-Steel Composite Components", solves the problems of poor airtightness of workpieces and low tensile strength of joints after welding in the existing brazing method. Using induction casting method, the tensile strength of composite components can reach 232MPa, but the application is limited, and the product is only used for the connection of copper-steel composite components.

The invention with application number 201210188109.3, "a production method of copper-steel composite sheet", adopts the steps of surface cleaning-texturing-spraying bonding layer-rolling-annealing-leveling, polishing and other steps to produce bimetallic composite materials, which is insufficient. The disadvantage is that this method has high requirements on the surface roughness of steel and copper, and needs to spray the bonding layer, which is not only cumbersome in the process, low in production efficiency, but also easy to cause uneven bonding interface.

In the invention with the application number of 201710630328.5, "a method of manufacturing a welded copper-steel composite cooling wall", the copper plate and the steel plate are first pretreated: cutting treatment, rust removal, grinding and polishing, leveling and bending, and then in an inert environment, high temperature, high pressure Under the conditions, the copper plate and the pretreated plate surface of the steel plate are opposite to each other, and the tracking welding is carried out while rolling to form a copper-steel composite cooling stave blank, and finally the subsequent processing is carried out. The disadvantage is that the invention adopts welding while rolling, which is very difficult, and it is difficult to carry out synchronously in large-scale production, and it is difficult to implement.

SUMMARY OF THE INVENTION

The object of the present invention is to overcome the above-mentioned problems and deficiencies and provide a kind of marine which takes into account cost and performance, makes the composite material have high seawater corrosion resistance, high strength, hardness, high shear strength and efficient production process. A copper-steel solid-liquid composite bimetallic material for engineering and a preparation method thereof.

The object of the present invention is achieved in this way:

A copper-steel solid-liquid composite bimetallic material for marine engineering, wherein the base plate of the bimetallic composite material is a steel plate, and a copper alloy plate is attached to the surface of the steel plate; the composition of the copper alloy is as follows in weight percentage: Ni: 15.0%～ 25.0%, Zn: 5.0% to 10.0%, Sn: 0.5% to 1.0%, Si: 2.0% to 3.0%, Mn: 0.5% to 1.3%, Fe: 1.0% to 1.5%, the balance is Cu and unavoidable Impurities; the composition of the steel by weight percentage is as follows: C: 0.07% to 0.15%, Si: 0.15% to 0.25%, Mn: 1.30% to 1.40%, P≤0.015%, S≤0.015%, Cr: 0.10 % to 0.20%, V: 0.05% to 0.10%, Mo: 0.02% to 0.08%, B: 0.002% to 0.003%, and the balance is Fe and inevitable impurities.

The bimetallic composite material of the invention is composed of a copper alloy plate and a base plate steel plate, the ratio of the thickness of the copper alloy to the steel slab is 1:(5.6-11.2), and the copper alloy plate is attached to one or both sides of the steel plate.

The cross-section hardness of the composite material is 192-208HV, the cross-section hardness difference is ≤16HV, the Z-direction tensile strength Rm≥440MPa, the elongation A≥25%, and the composite interface shear strength is 240-260MPa.

The copper alloy composition design reasons of the present invention are as follows:

Ni: In the present invention, Ni has the effect of improving the strength, toughness and stress corrosion cracking resistance of the copper alloy, and at the same time, it can improve the processing performance of the alloy, improve the corrosion fatigue resistance, erosion corrosion resistance, cavitation corrosion resistance and cavitation resistance of the alloy. Anti-marine biofouling and other properties, the present invention can achieve the corrosion resistance effect of B30 alloy under the combined action of other alloy elements, and at the same time reduce the cost, so the present invention chooses to add Ni: 15.0% to 25.0%.

Zn: Improves the plasticity of the copper alloy α solid solution in the present invention, and the alloy strength increases continuously with the increase of Zn content. However, if the Zn content is too high, the plasticity of the material will be affected, so the present invention chooses to add Zn: 5.0% to 10.0%.

Sn: The addition of Sn in the present invention can not only improve the mechanical properties of the copper alloy, but also inhibit the de-Zn removal of the copper alloy, thereby enhancing the corrosion resistance of the copper alloy. In the present invention, an appropriate amount of Sn and Ni are added at the same time, on the one hand, the strength and hardness can be improved, better elastic properties can be obtained, and the cost can be greatly saved in the preparation process. Therefore, the present invention selects to add Sn: 0.5% to 1.0%.

Si: In this kind of copper alloy, adding an appropriate amount of Si can improve the strength without losing its corrosion resistance, so the present invention chooses to add Si: 2.0% to 3.0%.

Mn: In the present invention, an appropriate amount of Mn plays a role of solid solution strengthening and improves the strength of the alloy without reducing the plasticity. Therefore, in the present invention, Mn is 0.5% to 1.3%.

Fe: Adding an appropriate amount of Fe is beneficial to grain refinement, and to form metal compounds with Ni to precipitate, which is beneficial to improve the erosion corrosion resistance of the alloy. However, if the Fe content is too high, brittle compounds are likely to appear on the grain boundaries, which will reduce the corrosion potential and thus affect the corrosion resistance of the alloy. Therefore, in the present invention, Fe: 1.0% to 1.5%.

The reasons for the composition design of the steel of the present invention are as follows:

C: In the present invention, a part of the carbon in the steel enters the matrix of the steel to cause solid solution strengthening, and the other part of the carbon will combine with the carbide-forming elements in the alloying elements to form alloyed carbides, so it has an impact on strength, plasticity, toughness and welding. Sex has a huge impact. However, if the carbon content is too high, it will form carbides with Cr, which will lead to the decline of corrosion resistance in the steel, and affect the performance of carbonization corrosion resistance.

Si: Silicon is one of the important elements for strengthening ferrite, which can significantly improve the strength and hardness of steel and improve hardenability. When in a strong oxidizing medium, Si can improve the corrosion resistance of steel. Studies have shown that Si has good Cl ^- corrosion resistance like Mo. The higher the Si content in steel, the more positive the pitting potential and the less likely it is to corrode . However, if the amount of Si is too large, the diameter and spacing of the spheroidized carbide particles will increase, and at the same time, the segregation will be promoted, resulting in the formation of a band-like structure, so that the lateral performance is lower than that of the longitudinal direction. Therefore, the present invention chooses to add Si content of 0.15 %～0.25%.

Mn: It is a solid solution strengthening element in steel, which refines grains, reduces ductile-brittle transition temperature, and improves hardenability. The presence of Mn in steel can change the nature and shape of oxides formed during solidification of steel. At the same time, it has a large affinity with S, which can avoid the formation of low-melting sulfide FeS on the grain boundary. However, if the content is too high, the plasticity of the steel will be affected, so in the present invention, the content of Mn is selected to be 1.30% to 1.40%.

P, S: S is distributed in the steel in the form of MnS, and MnS is elongated along the rolling direction during hot rolling, which significantly reduces the transverse mechanical properties of sulfur free-cutting steel and aggravates the anisotropy of the steel. At the same time, S is harmful to the corrosion resistance of die steel and deteriorates the welding performance. Although P can properly increase the hardness of ferrite and improve the surface finish and cutting performance of parts, too much P in the steel will increase cold brittleness, and too much S and P will affect the homogeneity and purity of the steel. Therefore, the present invention selects to add P≤0.015% and S≤0.015%.

Cr: Cr can improve the hardenability of iron-chromium alloys, passivate steel and impart good corrosion resistance and rust resistance. The corrosion potential of Cr is more negative than that of iron, and its passivation ability is stronger than that of iron. In iron-chromium alloys, the increase of Cr content will cause the corrosion potential and critical passivation potential of the alloy to shift to the negative potential direction. Therefore, in the present invention, the content of Cr is selected to be 0.10% to 0.20%.

V: V exists stably as carbides such as V ₄ C ₃ in the steel of the present invention, usually in the state of fine particles to inhibit the movement of grain boundaries and grain growth in the steel, and part of C and N in the steel are fixed, which directly affects the steel. The content of ferrite and pearlite in the medium and change the distribution and morphology of ferrite. The V solid dissolved in austenite can improve the stability of supercooled austenite, reduce the transformation temperature, make the pearlite group smaller, the pearlite flakes become fragmented, and the space between the flakes becomes smaller. In the present invention, the addition of V can effectively refine the crystal grains and play a role in refining and strengthening. Therefore, the present invention chooses to add V in a content of 0.05% to 0.10%.

Mo: Mo can improve the hardenability of steel in steel, and at the same time form special carbides in steel to improve the heat treatment stability of steel. Mo element is one of the most effective elements to improve the pitting corrosion resistance of this kind of steel. Mo element dissolves in the form of MoO ₄ ^2- and is adsorbed on the metal surface to form a protective film, which inhibits the destruction of Cl ^- , prevents the penetration of Cl ^- , and makes the The pitting corrosion potential increases and the pitting corrosion rate decreases, thereby improving the pitting corrosion resistance, but too much Mo content will promote the formation of delta ferrite, resulting in adverse effects. Therefore, in the present invention, the content of Mo is selected to be 0.02% to 0.08%.

B: Since the atomic radius ratio of B to Fe is 0.79, boron atoms will cause larger distortion energy whether they form an interstitial solid solution with iron or substitute for a solid solution. Therefore, B is easy to segregate at the austenite grain boundary, filling part of the grain boundary defects leads to a decrease in the energy at the grain boundary, the energy fluctuation at the grain boundary is reduced, the diffusion of carbon atoms at the grain boundary is hindered, and the new phase is present when the austenite decomposes. Difficulty in nucleation at the austenite grain boundary, resulting in an increase in the incubation period of austenite decomposition, inhibiting the nucleation of proeutectoid ferrite at the austenite grain boundary, and improving the hardenability, which is beneficial to ensure the steel for marine engineering. Full thickness strength. However, if the B content is too high, strong segregation tends to occur at the grain boundary, forming an enrichment band with a certain width, forming a carbide precipitation phase, which is easy to cause stress concentration during the deformation process. The carbide also provides a continuous expansion path, showing Cleavage fracture and excessive precipitation of B will also have a certain impact on toughness. Therefore, in the present invention, the content of B is selected to be 0.002% to 0.003%.

The second technical solution of the present invention is to provide a method for preparing a copper-steel solid-liquid composite bimetallic material for marine engineering, including steel plate pretreatment, preheating, solid-liquid composite, composite slab heating, hot rolling, straightening, and heat treatment;

(1) Steel plate pretreatment: First, mill grooves on the surface of the steel plate, the depth of the grooves is 5-8mm, and the groove surface is subjected to mechanical grinding, pickling, water washing, and drying, so that the rust on the groove surface is polished off to make it The bright fresh metal surface is exposed, and the surface of the steel plate is also roughened, which greatly increases the effective contact area between the copper alloy and the base steel plate, which is beneficial to improve the mechanical properties of the transition interface of the composite material. The steel plate is then degreasing. In order to effectively remove the oil stains on the surface of the steel plate, the degreasing solution is heated to 60℃～70℃ to degreasing the surface of the steel plate, followed by cleaning with acetone, coating with antioxidants and drying for later use.

(2) Preheating: The pretreated steel plate is heated to 850°C to 900°C, and then placed in the graphite mold cavity. The preheating of the steel plate can ensure that there is a certain heat volume ratio between the liquid copper alloy and the solid steel plate during the casting process of the copper alloy, because the element diffusion phenomenon will occur when the copper alloy and the steel plate are compounded, and a higher preheating temperature can improve the copper alloy. The diffusion reaction conditions during the composite process of the alloy and the matrix steel plate make the atoms at the interface junction have sufficient energy for interdiffusion. Preferably, the preheating process is under inert gas protection or vacuum protection.

(3) Solid-liquid composite: Fill the graphite mold cavity with inert gas before pouring to reduce the oxygen content and reduce oxidation; then quickly pour the smelted copper alloy metal liquid onto the surface of the pretreated steel plate, and the pouring temperature is 1150 ℃～1200℃, then air-cooled until the temperature of the copper alloy side is 950℃～980℃; take out the casted billet and immediately spray cooling water at the bottom of the steel plate for cooling, until the billet is cooled to 200℃～250℃ after casting, immediately The copper alloy is coated with antioxidants to prevent oxidation of the copper alloy, and then air-cooled to room temperature, and the copper alloy/steel bimetallic composite slab is obtained by subsequent machining. The thickness of the copper alloy slab in the bimetallic composite slab is 5-8 mm, and the ratio of the slab thickness of the copper alloy to the steel is 1:(5-10).

This thickness requirement is adopted in the present invention, on the one hand, according to the flow deformation behavior of the copper-steel bimetal, a relatively uniform metal flow can be obtained in the subsequent rolling process; Seawater corrosion resistance and anti-oxidant growth ability, while saving precious metal material copper alloy, has high economic and social benefits.

Temperature plays a major role in promoting atomic diffusion. The higher the temperature, the more intense the thermal motion of the atoms, and the greater the probability of the atoms being activated and migrating under the action of a high-temperature heat source. energy, migrate away from the equilibrium position. The invention adopts higher pouring temperature of copper alloy, so that the number of atoms deviating from the equilibrium position increases, the probability of bonding between atoms increases, the effective bonding point of the interface increases rapidly, the width of the composite interface of the slab increases, and the bonding strength of the interface increases.

In the present invention, the bimetallic composite billet adopts the method of segmental cooling after pouring. On the one hand, the cooling speed of the copper alloy and the steel plate after pouring and compounding is prevented from being slow, and the copper alloy and the steel plate are kept in a high temperature section for a long time, so that the crystal grains grow up, which affects the shear strength and tensile strength of the material. The strength has an adverse effect. On the one hand, the cooling rate is increased to reduce oxidation, reduce the generation of oxides at the joint surface of the composite slab, and at the same time improve the production efficiency and shorten the composite material preparation cycle.

(4) Composite slab heating: Due to the large difference in melting point between copper alloy and steel, the hot rolling temperature of steel is almost close to the melting temperature of copper alloy, so the rolling heating temperature should be selected reasonably. The heating temperature of the slab of the present invention is controlled at 910 DEG C to 960 DEG C, and the soaking section is kept for 2 to 3 hours. Preferably, the heating process of the composite plate is under inert gas protection or vacuum protection.

(5) Hot rolling: Since the thermal expansion coefficient and elongation of steel and copper alloy are different, the reduction should be reasonably determined to ensure the composite strength and equipment safety. The rolling temperature is 800°C to 850°C, the hot rolling temperature of the present invention is controlled above the recrystallization temperature of the copper alloy with a lower melting point, the reduction ratio of the first pass is controlled to be 15% to 17%, and the copper/steel slab thickness ratio, The combined effect of thermal deformation temperature and reduction ratio has a great influence on the flow difference of bimetallic composites. Using this thickness ratio, hot rolling temperature and large first pass reduction ratio can make the bonding interface straight. The intermetallic elements on both sides diffuse more, and the diffusion distance is larger. It is far away from the difficult deformation area and enters the easily deformed area, which is conducive to the coordinated deformation between metals, and the first pass adopts a larger reduction rate to break the branches in the as-cast structure. crystals, increase the newly formed bonding interface at the composite, reduce the inclusions at the bonding and break and separate, and prepare for the subsequent rolling. Due to the different ductility of steel plates and copper alloys, after rolling, the copper alloys are bound to spread around. When the copper alloys are spread around, an extrusion force and a transverse tearing force are bound to be generated. Therefore, in order to prevent the copper alloy surface and The joint interface is cracked, and the interface joint and the matrix structure are uniform and small. The subsequent production is produced by multi-pass rolling with small deformation. During the rolling process, the copper alloy is on the top and the steel plate is on the bottom to prevent the copper alloy from being worn and scratched. In the present invention, the total reduction ratio of the rolling process is controlled to be 50% to 60%. On the one hand, the distribution of brittle inclusions and oxides at the interface can be more dispersed, and the composite interface forms a metallurgical bond; The entanglement of faults makes the grains elongate, break and fiberize, which increases the plastic deformation resistance of the metal, thus further improving the shear strength and tensile strength. If the deformation rate is further increased, it has little effect on the thickness of the diffusion layer at the bonding interface, that is, the bonding interface properties are almost unchanged, and due to the difference in mechanical properties between copper alloy and steel, incompatible deformation is likely to occur during the rolling process, so further increase the deformation. It is easy to have an adverse effect on composite materials. Preferably, the hot rolling process is under inert gas protection or vacuum protection.

(6) Heat treatment: The hot-rolled composite plate is then subjected to tempering heat treatment; the tempering temperature is 500°C to 550°C, the net holding time is 2 to 3 hours, and the furnace is air-cooled to room temperature. Due to the limited diffusion of metal atoms in the bonding layer of the composite material and the existence of a certain internal stress during the rolling process, the strength of the composite material will be reduced. Therefore, the use of tempering heat treatment to diffuse elements is conducive to improving the strength of the bonding interface, reducing the internal stress between atoms at the composite interface, and further improving the efficiency of atomic diffusion. At the same time, it can effectively remove the stress residual caused by rolling, and ensure that the product has good comprehensive mechanics. performance and good metallurgical combination. Preferably, the heat treatment process is under inert gas protection or vacuum protection.

Further, any process in the step (2), step (4)-step (6) adopts inert gas or vacuum protection; the inert gas is argon; the purpose is to prevent oxidation of the copper alloy.

The beneficial effects of the present invention are:

The bimetallic composite material of the invention is composed of a copper alloy plate and a base plate steel plate. The copper alloy plate of the present invention adopts the copper alloy composition design idea of increasing Sn to reduce Ni, and Si and Mn work together to improve the strength. The copper-steel bimetallic composite material is obtained by cooperating with the production processes of pretreatment, preheating, solid-liquid composite, composite slab heating, hot rolling, straightening and heat treatment of the base copper alloy steel plate, so that the material has a cross-sectional Vickers of 192-208HV Hardness, section hardness difference ≤ 16HV, Z-direction tensile strength Rm ≥ 440MPa, elongation A ≥ 25%, composite interface shear strength 240-260MPa, all bending tests are qualified, and it has good seawater corrosion resistance. The bimetallic composite material of the invention has broad application prospects in marine engineering.

Detailed ways

The present invention will be further illustrated by the following examples.

In the embodiment of the present invention, according to the component distribution ratio of the technical solution, the specific process includes steel plate pretreatment, preheating, solid-liquid composite, composite slab heating, hot rolling, straightening, and heat treatment.

(1) Steel plate pretreatment: First, mill grooves on the surface of the steel plate, the depth of the grooves is 5-8mm, and the groove surface is subjected to mechanical grinding, pickling, water washing, and drying, so that the rust on the groove surface is polished off to make it Expose the bright fresh metal surface, then degreasing the steel plate, heat the degreasing solution to 60-70 ℃ to degrease the surface of the steel plate, apply antioxidant, and dry it for later use;

(2) Preheating: heat the pretreated steel plate to 850-900°C, and place it in the mold cavity;

(3) Solid-liquid composite: Fill the mold cavity with inert gas before pouring, and then quickly pour the smelted copper alloy metal liquid onto the surface of the pretreated steel plate. When the temperature of the copper alloy side is 950-980°C; take out the casted billet and immediately spray cooling water at the bottom of the steel plate for cooling until the billet is cooled to 200-250°C after pouring, immediately coat the copper alloy side with antioxidants, and then air-cool to room temperature, The copper-steel bimetallic composite slab is obtained by subsequent machining;

(4) Heating of composite slab: the heating temperature of composite slab is 910～960℃, and the soaking section is kept for 2～3h;

(5) Hot rolling: the rolling temperature is controlled at 800-850°C, the first pass controls the reduction rate of 15% to 17%, and the total rolling reduction rate is 50% to 60%;

(6) Heat treatment: The hot-rolled clad plate is then subjected to tempering heat treatment, the tempering temperature is 500-550 °C, the net holding time is 2-3 hours, and it is air-cooled to room temperature.

In the step (3), the thickness of the copper alloy slab in the bimetallic composite material slab is 5-8 mm, and the ratio of the slab thickness of the copper alloy to the steel is 1:(5-10).

The mold cavity in the step (2) is a graphite mold cavity.

Any process in the step (2), step (4) to step (6) can be protected by inert gas or vacuum. The inert gas is argon.

The composition of the composite material of the embodiment of the present invention is shown in Table 1. The main process parameters of the composite material pretreatment and casting in the embodiment of the present invention are shown in Table 2. The main process parameters of the composite material heating and hot rolling in the embodiment of the present invention are shown in Table 3. The heat treatment process of the composite material in the embodiment of the present invention is shown in Table 4. The Vickers hardness of the composite material in the embodiment of the present invention is shown in Table 5. See Table 6 for the Z-direction tensile properties of the composite materials of the embodiments of the present invention. Table 7 shows the composite interface shear strength and bending properties of the composite materials of the embodiments of the present invention. The average corrosion rate and maximum pitting depth of the composite materials in the embodiment of the present invention are shown in Table 8.

Table 1 Composition (wt%) of the composite material of the embodiment of the present invention

Table 2 The main process parameters of composite material pretreatment and casting in the embodiment of the present invention

Table 3 The main process parameters of the composite material heating and hot rolling in the embodiment of the present invention

Table 4 The heat treatment process of the composite material according to the embodiment of the present invention

Example Heating temperature/℃ Holding time/h 1 510 2.5 2 550 2.3 3 525 2.9 4 518 3.0 5 500 2.1 6 505 2.0 7 520 2.4 8 530 2.7 9 540 2.8 10 545 2.2

Table 5 Vickers hardness of composite materials according to embodiments of the present invention

Table 6 Z-direction tensile properties of composite materials according to embodiments of the present invention

Example Rm(MPa) A(%) 1 445 25.6 2 448 25.2 3 442 25.9 4 440 26.2 5 449 25.0 6 450 25.0 7 441 26.3 8 447 25.7 9 444 25.8 10 443 26.1

Table 7 The composite interface shear strength and flexural properties of composite materials according to the invention examples

Table 8 Average corrosion rate and maximum pitting depth of composite materials according to embodiments of the present invention

Example Average corrosion rate (mm/a) Maximum pitting depth (mm) 1 0.015 0.078 2 0.0137 0.077 3 0.0146 0.071 4 0.014 0.072 5 0.012 0.075 6 0.0135 0.079 7 0.013 0.074 8 0.0127 0.073 9 0.0138 0.076 10 0.0126 0.070

Remarks: Corrosion test: The average corrosion rate and maximum pitting depth of the copper side of each example (50×20×2mm) in artificial seawater (pH=8) at a temperature of 25°C for 3 months

In order to express the present invention, the present invention has been properly and fully described above through the examples. The above embodiments are only used to illustrate the present invention, but not to limit the present invention. Under the circumstance of the spirit and scope of the invention, various changes and modifications can also be made, and any modifications, equivalent replacements, improvements, etc. made should be included within the protection scope of the present invention, and the patent protection scope of the present invention should be The claims are limited.

Claims (8)

1. a copper-steel solid-liquid composite bimetallic material for marine engineering, is characterized in that, in the described composite bimetallic material, substrate is a steel plate, and a copper alloy plate is attached to the surface of the steel plate; the composition of the copper alloy is as follows by weight percentage : Ni: 15.0%~25.0%, Zn: 5.0%~10.0%, Sn: 0.5%~1.0%, Si: 2.0%~3.0%, Mn: 0.5%~1.3%, Fe: 1.0%~1.5%, the remainder The amount is Cu and unavoidable impurities; the composition of the steel is as follows: C: 0.07%~0.15%, Si: 0.15%~0.25%, Mn: 1.30%~1.40%, P≤0.015%, S≤ 0.015%, Cr: 0.10%~0.20%, V: 0.05%~0.10%, Mo: 0.02%~0.08%, B: 0.002%~0.003%, the balance is Fe and inevitable impurities; A method for preparing a copper-steel solid-liquid composite bimetallic material for engineering, the specific processes include steel plate pretreatment, preheating, solid-liquid composite, composite slab heating, hot rolling, and heat treatment; (1) Steel plate pretreatment: First, mill a groove on the surface of the steel plate, the depth of the groove is 5~8mm, and the surface of the groove is subjected to mechanical grinding, pickling, water washing and drying, so that the rust on the surface of the groove is polished to make it Expose the bright fresh metal surface, then degreasing the steel plate, heat the degreasing solution to 60~70℃ to degrease the surface of the steel plate, apply antioxidant, and dry it for later use; (2) Preheating: heat the pretreated steel plate to 850~900℃, and place it in the mold cavity; (3) Solid-liquid composite: Fill the mold cavity with inert gas before pouring, and then quickly pour the smelted copper alloy metal liquid onto the surface of the pretreated steel plate. When the temperature of the copper alloy side is 950~980℃; take out the casted billet and immediately spray cooling water at the bottom of the steel plate for cooling, until the billet is cooled to 200~250℃ after pouring, and then air-cooled to room temperature. Metal composite slab; (4) Composite slab heating: The composite slab heating temperature is 910~960℃, and the soaking section is kept for 2~3h; (5) Hot rolling: The rolling temperature is controlled at 800~850°C, the first pass is controlled to reduce the rate of 15% to 17%, and the total rolling reduction rate is 50% to 60%; (6) Heat treatment: The hot-rolled clad plate is then subjected to tempering heat treatment, the tempering temperature is 500~550℃, the net holding time is 2~3h, and it is air-cooled to room temperature. 2 . The copper-steel solid-liquid composite bimetallic material for marine engineering according to claim 1 , wherein the ratio of the thickness of the copper alloy plate to the steel plate is 1: (5.6~11.2). 3 . 3 . The copper-steel solid-liquid composite bimetallic material for marine engineering according to claim 1 , wherein the copper alloy plate is attached to one side or both sides of the steel plate. 4 . 4. The copper-steel solid-liquid composite bimetallic material for marine engineering according to claim 1, wherein the composite material has a cross-sectional hardness of 192-208HV, a cross-sectional hardness difference≤16HV, and a Z-direction tensile strength Rm≥ 440MPa, elongation A≥25%, composite interface shear strength 240~260MP. 5. The copper-steel solid-liquid composite bimetallic material for marine engineering according to claim 1, wherein in step (3), the thickness of the copper alloy slab in the composite bimetallic material slab is 5-8 mm, and the copper alloy slab has a thickness of 5-8 mm. The ratio of the thickness of alloy slab to steel slab is 1:(5~10). 6 . The copper-steel solid-liquid composite bimetallic material for marine engineering according to claim 1 , wherein the mold cavity in step (2) is a graphite mold cavity. 7 . 7. A copper-steel solid-liquid composite bimetallic material for marine engineering according to claim 1, characterized in that, any process in step (2), step (4)-step (6) adopts inert gas or Vacuum protection. 8 . The copper-steel solid-liquid composite bimetallic material for marine engineering according to claim 7 , wherein the inert gas is argon. 9 .