High-strength and high-elongation nickel-silicon bronze strip and preparation method thereof

Abstract

The invention discloses a high-strength and high-elongation nickel-silicon bronze strip and a preparation method thereof, and belongs to the technical field of copper-based alloys. The preparation method comprises the following steps: carrying out smelting, refining, two-stage filtering, casting and semi-continuous casting according to nickel-silicon bronze components to obtain a cast ingot, and carrying out hot rolling, annealing, surface milling, rough rolling, first cleaning and brushing, first solid solution, finish rolling, second solid solution, finished product rolling, aging, second cleaning and brushing, straightening, slitting and the like on the cast ingot after heating to obtain the nickel-silicon bronze strip. According to the method, the problem of surface oxidation of the strip is solved, the surface and internal quality of the strip is improved, the strip strength and elongation are improved, the strip yield is increased, and batch production of the large-coil heavy nickel-silicon bronze strip can be met.

Description

Technical Field

[0001] The present invention belongs to the technical field of copper-based alloys, and in particular relates to a high-strength and high-elongation nickel-silicon bronze strip and a preparation method thereof. Background Art

[0002] Nickel-silicon bronze strips offer excellent strength, conductivity, corrosion resistance, and stress relaxation resistance, making them widely used in applications such as connectors, plug-ins, and sensor components in the electronics, automotive, marine, and aerospace industries. High-strength and high-elongation nickel-silicon bronze strips are required for precision electronic circuit connections in aerospace and flexible connectors in high-end electronic equipment. Their high strength ensures reliability in complex stress environments, while their high elongation accommodates various assembly deformation requirements.

[0003] Currently, nickel-silicon bronze strips are primarily produced through vacuum / non-vacuum melting and rolling. Chinese patent CN101289716A discloses a "process for processing nickel-silicon bronze alloy materials." The ingredients are weighed and proportioned according to the nickel-silicon bronze material composition, then placed in a smelting furnace and cast into ingots. The ingots are then heated, hot-rolled and quenched, milled, cold-rolled, trimmed, annealed, cold-rolled, sheared, and stored to produce nickel-silicon bronze alloy plates and strips. During this process, an oxide film forms on the surface of the plates and strips during the heating, cold-rolling, annealing, and cold-rolling processes, due to the high temperatures involved. During subsequent rolling deformation, inclusions from the shattered oxide film become embedded within the plates and strips under the action of the rolling force, affecting the internal and surface quality of the product and failing to meet the demand for large-volume, heavy-duty products. Chinese patent CN112795810A discloses a "method for preparing C70250 nickel-silicon bronze strip." The materials are weighed and mixed according to their composition ratios. The materials are then added to a vacuum induction melting furnace to produce a molten alloy. This is then cast once to produce a block-shaped alloy electrode blank. A deoxidizer is added during the casting process to prevent metal oxidation and the formation of defects such as inclusions and bubbles. The resulting alloy electrode blank is then subjected to vacuum consumable melting and a secondary casting process to produce an alloy blank. The alloy blank is then placed in a mold and pressed to form a green alloy blank. After demolding, the blank is placed in a reactor for sintering, cooled, and removed from the furnace. The C70250 alloy strip is then rolled. This preparation method addresses the issue of metal oxidation during the casting process and significantly reduces the formation of defects such as inclusions and bubbles. However, the subsequent strip rolling process is unclear, and the processing rate and number of passes are not specified. The green alloy blank is prone to cracking at high processing rates, which in turn affects the yield rate.

[0004] In summary, existing literature mainly focuses on the oxidation problems during the smelting process of nickel-silicon bronze and the rolling deformation process, but there is little research on the surface and internal quality problems caused by surface oxidation of the strip during rolling deformation. However, the quality problems caused by surface oxidation significantly affect the strength and elongation of nickel-silicon bronze strip. Summary of the Invention

[0005] In view of this, the present invention proposes a high-strength and high-elongation nickel-silicon bronze strip and a preparation method thereof. The nickel-silicon bronze composition is smelted, refined, two-stage filtered, cast, and semi-continuously cast to obtain an ingot. Subsequently, the ingot is heated and hot rolled, annealed, milled, rough rolled, first cleaning and brushing, first solid solution, finish rolled, second solid solution, finished product rolled, aging, second cleaning and brushing, straightened, and slitting to produce the nickel-silicon bronze strip. The surface oxidation problem of the strip is solved, the surface and internal quality of the strip are improved, and the strip strength and elongation are increased while the strip yield is increased, which can meet the needs of mass production of large-volume heavy nickel-silicon bronze strip.

[0006] A first aspect of the present invention provides a method for preparing a high-strength and high-elongation nickel-silicon bronze strip, the method comprising:

[0007] Step S1, weighing raw materials according to the chemical composition and mass percentage of the nickel-silicon bronze strip, and sequentially performing smelting, refining, two-stage filtration, casting and semi-continuous casting on the raw materials to obtain an ingot;

[0008] The chemical composition and mass percentage of the nickel-silicon bronze strip are as follows: Ni: 2.2-4.0%, Si: 0.5-0.90%, Mg: 0.05-0.30%, and the balance is Cu and unavoidable impurities;

[0009] Step S2, holding the ingot at 950-980° C. for 6-15 hours and then hot rolling to obtain a strip with a thickness of 16-18 mm;

[0010] Step S3, annealing the strip under inert gas protection, and then cooling it to 35°C before taking it out of the furnace; the annealing temperature is increased at a rate of 140-170°C / h, the temperature is 560-600°C, and the holding time is 7-10h;

[0011] Step S4, sequentially performing milling, rough rolling, edge trimming and first cleaning and brushing on the annealed strip;

[0012] The degreasing agent for the first cleaning and brushing is a sodium hydroxide aqueous solution with a mass concentration of 1-2%, the pickling agent for the first cleaning and brushing is a mixture of sulfuric acid, hydrogen peroxide and deionized water in a volume ratio of 1:1:3, and the passivating liquid for the first cleaning and brushing is a benzotriazole aqueous solution with a mass concentration of 0.1-0.3%;

[0013] Step S5, subjecting the strip that has undergone the first cleaning and brushing to a first solution treatment under the protection of a mixed gas; the temperature of the first solution treatment is 880-910° C., and the strip speed is 7-23 m / min;

[0014] Step S6, finishing rolling the strip after the first solution treatment;

[0015] Step S7, subjecting the finish-rolled strip to a second solid solution treatment under the protection of a mixed gas; the second solid solution treatment temperature is 880-910° C., and the strip speed is 24-40 m / min;

[0016] Step S8, rolling the finished strip after the second solution treatment and then aging it, then cooling it to 40°C and then taking it out of the furnace; the aging heating rate is 80-120°C / h, the temperature is 440-540°C, and the holding time is 4-6h;

[0017] Step S9, sequentially cleaning, brushing, straightening, and slitting the aged strip to obtain a nickel-silicon bronze strip;

[0018] The degreasing agent for the second cleaning and brushing is a sodium hydroxide aqueous solution with a mass concentration of 1-2%, the pickling agent for the second cleaning and brushing is a mixture of sulfuric acid, hydrogen peroxide and deionized water with a volume ratio of 1:1:2, and the passivating liquid for the second cleaning and brushing is a benzotriazole aqueous solution with a mass concentration of 0.1-0.3%.

[0019] According to the preparation method described in the first aspect of the present invention, in the step S1, the smelting temperature is 1350-1390° C., and the time is 100-180 min; and the refining time is 60-100 min.

[0020] According to the preparation method described in the first aspect of the present invention, in the step S1, the casting temperature is 1300-1350°C.

[0021] According to the preparation method described in the first aspect of the present invention, in the step S1, the speed of the semi-continuous casting is 50-110 mm / min, the cooling water flow rate is 12-16 m / min, and the cooling water flow rate is 12-16 m / min. 3 / h.

[0022] According to the preparation method described in the first aspect of the present invention, in the step S2, the hot rolling is performed 7-9 times, the processing rate of each time is 14-28%, and the total processing rate is 88-92%.

[0023] According to the preparation method described in the first aspect of the present invention, in the step S4, the rough rolling is performed 5-7 times, and the processing rate of each time is 12-20%.

[0024] According to the preparation method described in the first aspect of the present invention, in step S4 or step S9, the first cleaning and brushing or the second cleaning and brushing is carried out in a box furnace for continuous cleaning and brushing, the temperature of the box furnace is 60-80°C, the belt speed is 5-25m / min, and the speed of the brush roller is 600-800r / min.

[0025] According to the preparation method described in the first aspect of the present invention, in the step S6, the number of finish rolling passes is 3-4, and the processing rate of each pass is 20-28%.

[0026] According to the preparation method described in the first aspect of the present invention, in the step S8, the number of passes for rolling the finished product is 1-3, and the processing rate of each pass is 18-24%.

[0027] A second aspect of the present invention provides a high-strength and high-elongation nickel-silicon bronze strip, which is prepared using the aforementioned preparation method.

[0028] The solution proposed by the present invention has the following technical effects:

[0029] The present invention firstly obtains an ingot through melting, refining, two-stage filtration, casting and semi-continuous casting according to the composition of nickel-silicon bronze. Subsequently, the ingot is subjected to processes such as hot rolling after heating, annealing, surface milling, rough rolling, first cleaning and brushing, first solid solution, finish rolling, second solid solution, finished product rolling, aging, second cleaning and brushing, straightening and slitting to obtain a nickel-silicon bronze strip. The problem of surface oxidation of the strip is solved, and the surface and internal quality of the strip are improved. While improving the strength and elongation of the strip, the yield of the strip is also increased, which can meet the needs of mass production of large-volume heavy nickel-silicon bronze strip. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0031] This embodiment provides a method for preparing a high-strength and high-elongation nickel-silicon bronze strip, the method comprising:

[0032] Step S1, weighing raw materials according to the chemical composition and mass percentage of the nickel-silicon bronze strip, and sequentially performing smelting, refining, two-stage filtration, casting and semi-continuous casting on the raw materials to obtain an ingot; wherein the chemical composition and mass percentage of the nickel-silicon bronze strip are as follows: Ni: 2.2-4.0%, Si: 0.5-0.90%, Mg: 0.05-0.30%, and the balance is Cu and unavoidable impurities.

[0033] The functions of each element in this embodiment are as follows:

[0034] Ni: Ni forms a solid solution with Cu, significantly improving the strength and hardness of the alloy; improving high-temperature performance and reducing the thermal expansion coefficient; too low a content will lead to insufficient strength; too high a content will precipitate a brittle phase, affecting the plasticity of the strip.

[0035] Si: It forms nano-scale precipitates such as Ni2Si with Ni, significantly increasing strength; improving fluidity, optimizing casting properties, and reducing shrinkage defects. Excessive Si content can lead to coarsening of the precipitates and reduce toughness.

[0036] Mg: Promotes nucleation, refines cast structure, and improves strength and fatigue resistance; forms a protective film on the surface to improve high-temperature oxidation resistance; excessive content will generate brittle Mg2Si phase, impairing processing performance; low content cannot effectively refine grains.

[0037] Cu: Provides excellent electrical conductivity, thermal conductivity and plasticity, ensuring that the material is easy to process and shape.

[0038] In some embodiments, in step S1, the smelting temperature is 1350-1390° C., and the time is 100-180 min; and the refining time is 60-100 min.

[0039] Preferably, the smelting is vacuum smelting.

[0040] The choice of melting temperature in this embodiment is related to the alloy composition. It is important to ensure the melting of the high-melting-point metal and the fluidity of the melt during the melting process, thereby ensuring the uniformity of the alloy composition. If the melting temperature is outside the 1350-1390°C range, low-melting-point elements may be burned away or high-temperature particles of high-melting-point elements may form, both of which will reduce the uniformity of the alloy composition.

[0041] In some embodiments, in step S1, the casting temperature is 1300-1350°C.

[0042] In some embodiments, in step S1, the semi-continuous casting speed is 50-110 mm / min, and the cooling water flow rate is 12-16 m / min. 3 / h.

[0043] Step S2, holding the ingot at 950-980° C. for 6-15 hours and then hot rolling to obtain a strip with a thickness of 16-18 mm;

[0044] In some embodiments, in step S2, the hot rolling is performed in 7-9 passes, the processing rate of each pass is 14-28%, and the total processing rate is 88-92%.

[0045] The effects of hot rolling in this embodiment are: (1) changing the size of the ingot to facilitate the subsequent process; (2) crushing the coarse grains formed by casting, refining the grain size, eliminating casting defects (such as shrinkage holes and pores), and thus improving the uniformity and density of the material; (3) enhancing the fluidity of the metal at high temperatures, and hot rolling can effectively heal the microcracks generated during the casting process and reduce internal defects; (4) transforming the cast structure. The hot rolling of the ingot must be above the recrystallization temperature. The high temperature and long time can improve the dendritic segregation during the melting and solidification process, promote the diffusion of solute atoms, and achieve uniformity of composition. Therefore, the hot rolling temperature in this embodiment is controlled at 950-980℃.

[0046] Step S3, annealing the strip under inert gas protection, and then cooling it to 35°C before taking it out of the furnace; the annealing heating rate is 140-170°C / h, the temperature is 560-600°C, and the holding time is 7-10h.

[0047] Preferably, the inert gas is nitrogen or argon.

[0048] The effects of annealing in this embodiment: (1) During the hot rolling process, large residual stresses will be generated inside the plate and strip. These residual stresses will cause deformation, cracking and other problems in the plate and strip during subsequent processing or use. Annealing can effectively eliminate residual stress by heating the metal atoms to obtain sufficient energy, rearrange and diffuse, thereby improving the dimensional stability and performance of the plate and strip. (2) The strip structure after hot rolling is usually coarse and uneven. Annealing can promote the recrystallization of the metal, refine the grains and make them uniform. After recrystallization annealing, the strength and hardness of the metal may be reduced, but the plasticity and toughness will be significantly improved, thereby improving the comprehensive mechanical properties of the plate and strip and making it easier to carry out subsequent processing. In order to eliminate the residual rolling stress in the strip and ensure the uniformity and processability of the alloy microstructure, the heating rate of annealing in this embodiment is 140-170℃ / h, the temperature is 560-600℃, and the holding time is 7-10h.

[0049] Step S4, the annealed strip is subjected to milling, rough rolling, edge trimming and first cleaning and brushing in sequence.

[0050] The effects of rough rolling in this embodiment are: (1) breaking up coarse grains, making the metal structure denser and more uniform, improving the internal structure of the metal, and enhancing the overall performance of the material. (2) Rough rolling can further roll the plate and strip material to meet the product specifications, providing billets with high dimensional accuracy and good plate shape for the subsequent finishing process. (3) Rough rolling can roll the annealed plate and strip material to a certain thickness and size, providing suitable billets for the finishing process.

[0051] The first cleaning and brushing process in this embodiment serves the following purposes: (1) to remove the oxide scale on the surface of the strip after hot rolling and annealing; (2) to improve the surface quality of the strip; and (3) to prevent scratches in subsequent processes. To eliminate scratches and surface protrusions in the strip, obtain a well-shaped strip, and maintain the internal microstructure of the strip, the process parameters of the first cleaning and brushing process in this embodiment are strictly controlled within an appropriate range.

[0052] The degreasing agent for the first cleaning and brushing is a sodium hydroxide aqueous solution with a mass concentration of 1-2%, the pickling agent for the first cleaning and brushing is a mixture of sulfuric acid, hydrogen peroxide, and deionized water in a volume ratio of 1:1:3, and the passivating solution for the first cleaning and brushing is a benzotriazole aqueous solution with a mass concentration of 0.1-0.3%. Preferably, the mass concentrations of the sulfuric acid and hydrogen peroxide are 98% and 20%, respectively.

[0053] In some embodiments, in step S4, the milling surface is milled by 0.3-0.7 mm on each of the upper and lower surfaces, and by 2-7 mm on each of the edges.

[0054] In some embodiments, in step S4, the rough rolling is performed 5-7 times, and the processing rate of each time is 12-20%.

[0055] In some embodiments, in step S4, the first cleaning and brushing is performed in a box furnace for continuous cleaning and brushing, the temperature of the box furnace is 60-80°C, the belt speed is 5-25m / min, and the speed of the brush roller is 600-800r / min.

[0056] Preferably, there are two brush rollers, namely a 600-mesh diamond brush roller and an 800-mesh alumina / nylon brush roller.

[0057] Specifically, the specific process of the first cleaning and brushing is as follows:

[0058] The trimmed strip is loaded into a box furnace for continuous cleaning and brushing. The furnace temperature is set at 60-80°C and the strip speed is 5-25m / min. The strip surface is first sprayed with a degreasing agent, then brushed with a 600-mesh diamond + 800-mesh alumina / nylon brush roller. After being rinsed with cold and hot water, the strip is immersed in a pickling agent and further brushed with a 600-mesh diamond + 800-mesh alumina / nylon brush roller. After being rinsed with cold and hot water, the strip surface is sprayed with a passivation solution and then air-dried at 80°C.

[0059] Step S5, subjecting the strip blank that has been cleaned and brushed for the first time to a first solid solution treatment under the protection of a mixed gas; the temperature of the first solid solution treatment is 880-910° C., and the strip speed is 7-23 m / min.

[0060] Preferably, the mixed gas is a mixed gas of hydrogen and nitrogen with the hydrogen ratio being 73-76%.

[0061] The purpose of the first solid solution in this embodiment is to dissolve the solute elements into the matrix to form a supersaturated solid solution, thereby eliminating processing stress and providing a good plate shape for subsequent processes, which is convenient for subsequent processing. The parameters of the solid solution process are selected based on the phase diagram. Excessively high temperature and slower belt speed will lead to abnormal growth of grains, resulting in poor microstructural uniformity and reduced material performance. Therefore, this embodiment limits the temperature of the first solid solution to 880-910°C and the belt speed to 7-23m / min.

[0062] Step S6, finishing rolling the strip that has undergone the first solution treatment.

[0063] In some embodiments, in step S6, the finishing rolling is performed 3-4 times, and the processing rate of each time is 20-28%.

[0064] The effects of finishing rolling in this embodiment are: (1) controlling the thickness tolerance of the plate and strip within a very small range to meet the strict requirements of different users for product thickness accuracy. (2) ensuring uniform extension of each part of the plate and strip during the rolling process, thereby improving the plate shape, reducing defects such as wavy and buckling, and improving the flatness of the plate and strip. An increase in the number of rolling passes and the processing rate per pass will lead to increased work hardening of the strip, which is not conducive to plate shape control, and will lead to the occurrence of wavy and buckling. This embodiment limits the number of finishing passes to 3-4 passes, and the processing rate per pass to 20-28%.

[0065] Step S7, subjecting the finish-rolled strip to a second solid solution treatment under the protection of a mixed gas; the temperature of the second solid solution treatment is 880-910° C., and the strip speed is 24-40 m / min.

[0066] Preferably, the mixed gas is a mixed gas of hydrogen and nitrogen with the hydrogen ratio being 73-76%.

[0067] The second solution treatment in this embodiment serves the following purposes: (1) to dissolve the solute atoms into the Cu matrix, preparing for subsequent aging precipitation; and (2) to eliminate the processing stresses generated during the finishing rolling process. The selection of process parameters depends on the phase diagram, ensuring that all solute atoms enter the matrix. To ensure that the solute atoms fully enter the Cu matrix and obtain a strip with good mechanical properties, this embodiment limits the second solution treatment temperature to 880-910°C and the strip speed to 24-40 m / min.

[0068] Step S8, after the second solution treatment, the finished strip is rolled and aged, and then cooled to 40°C before being taken out of the furnace; the aging heating rate is 80-120°C / h, the temperature is 440-540°C, and the holding time is 4-6h.

[0069] The effects of aging in this embodiment are: (1) decomposition of the supersaturated solid solution during aging, precipitating fine, dispersed strengthening phase particles, improving the material's strength and hardness; (2) stabilization of the microstructure and properties. The selection of process parameters relies on the phase diagram to ensure complete precipitation of the solid solution atoms and maximize the material's mechanical properties. To obtain a strip with excellent mechanical properties, this embodiment limits the aging heating rate to 80-120°C / h, the temperature to 440-540°C, and the holding time to 4-6 hours.

[0070] In some embodiments, in step S8, the number of passes for rolling the finished product is 1-3, and the processing rate of each pass is 18-24%.

[0071] Step S9, the aged strip is sequentially cleaned, brushed, straightened and cut for the second time to obtain a nickel silicon bronze strip.

[0072] The purpose of the second cleaning and brushing step in this embodiment is to eliminate surface oxidation caused by finishing, solution treatment, and aging treatment before final product completion, thereby achieving a brighter surface. The selection of process parameters depends on the thickness of the surface oxide layer and the number of defects. Using parameters outside the limits of this embodiment may result in incomplete defect elimination, affecting the product yield.

[0073] The degreasing agent for the second cleaning and brushing is a sodium hydroxide aqueous solution with a mass concentration of 1-2%, the pickling agent for the second cleaning and brushing is a mixture of sulfuric acid, hydrogen peroxide, and deionized water in a volume ratio of 1:1:2, and the passivating solution for the second cleaning and brushing is a benzotriazole aqueous solution with a mass concentration of 0.1-0.3%. Preferably, the mass concentrations of the sulfuric acid and hydrogen peroxide are 98% and 20%, respectively.

[0074] In some embodiments, in step S9, the second cleaning and brushing is performed in a box furnace for continuous cleaning and brushing, the temperature of the box furnace is 60-80°C, the belt speed is 5-25m / min, and the speed of the brush roller is 600-800r / min.

[0075] Preferably, there are two brush rollers, namely a 1000-mesh non-woven brush roller and a 2000-mesh non-woven brush roller.

[0076] Specifically, the specific process of the second cleaning and brushing is as follows:

[0077] The trimmed strip is loaded into a box-type furnace for continuous cleaning and brushing. The temperature of the box-type furnace is set at 60-80°C and the strip speed is 5-25m / min. First, a degreasing agent is sprayed on the strip surface, and then it is brushed with a 1000-mesh non-woven + 2000-mesh non-woven brush roller. After rinsing with cold and hot water, it is immersed in a pickling agent and brushed with a 1000-mesh non-woven + 2000-mesh non-woven brush roller. After rinsing with cold and hot water, the strip surface is sprayed with a passivation solution and then air-dried at 80°C.

[0078] In a second aspect of this embodiment, a high-strength and high-elongation nickel-silicon bronze strip is provided. The nickel-silicon bronze strip is prepared using the aforementioned preparation method.

[0079] Example 1

[0080] In the first step, the raw materials were weighed according to the chemical composition and mass percentage of the nickel-silicon bronze strip, and then placed in a vacuum induction melting furnace for smelting at 1370°C for 150 minutes and 80 minutes of refining. After refining, the alloy solution was filtered through two stages and then cast into a water-cooled crystallizer at 1320°C. Semi-continuous casting was performed at a casting speed of 70 mm / min, and the cooling water flow rate was 14 m / min. 3 / h, to obtain nickel-silicon bronze alloy ingots.

[0081] In the second step, the ingot is kept at 965° C. for 10 hours and then hot rolled for 8 passes. The processing rate of each pass is 20-24%, and the total processing rate is 90%, thereby obtaining a nickel-silicon bronze strip with a thickness of 17 mm.

[0082] In the third step, the nickel-silicon bronze strip is placed in a bell-type annealing furnace under nitrogen protection, heated to 580°C at a heating rate of 155°C / h, and then kept warm for 8.5 hours for annealing. It is then cooled to 35°C and taken out of the furnace.

[0083] The fourth step is to mill the nickel-silicon bronze strip after it leaves the furnace. The upper and lower surfaces are milled to 0.7mm each, with a tolerance of ±0.02mm, and the left and right sides are milled to 2mm each, with a tolerance of ±0.02mm. It is then rough rolled in six passes, with a processing rate of 16% per pass, and then trimmed.

[0084] In the fifth step, the trimmed nickel-silicon bronze strip is loaded into a box furnace for continuous cleaning and brushing. The temperature of the box furnace is set to 70°C and the running speed of the strip is 15m / min. First, a sodium hydroxide aqueous solution with a mass concentration of 1.5% is sprayed on the surface of the strip, and then it is brushed with a 600-mesh diamond + 800-mesh alumina / nylon brush roller at a speed of 700r / min. After being rinsed with cold and hot water, it is immersed in a mixture of sulfuric acid, hydrogen peroxide and deionized water with a volume ratio of 1:1:3, and then it is brushed again with a 600-mesh diamond + 800-mesh alumina / nylon brush roller at a speed of 700r / min. After being rinsed with cold and hot water, a 0.2% benzotriazole aqueous solution is sprayed on the surface of the nickel-silicon bronze strip, and then it is blown and dried at 80°C.

[0085] In the sixth step, the cleaned and brushed strip is passed through a vertical continuous quenching furnace for a first solution treatment at 895°C under a mixed gas atmosphere at a speed of 15 m / min. The mixed gas is a combination of hydrogen and nitrogen, with the hydrogen accounting for 76%.

[0086] Step 7: Finish rolling the nickel-silicon bronze strip that has undergone the first solid solution treatment for 3 passes, with a processing rate of 24% per pass;

[0087] In the eighth step, the nickel-silicon bronze strip, after finish rolling, passes through a vertical continuous quenching furnace for a second solution treatment at 895°C under a mixed gas atmosphere at a speed of 32 m / min. The mixed gas is hydrogen and nitrogen, with hydrogen accounting for 76%.

[0088] In the ninth step, the nickel-silicon bronze strip that has undergone the second solid solution treatment is rolled into finished products, with two rolling passes and a pass processing rate of 21%.

[0089] In the tenth step, the finished rolled nickel-silicon bronze strip is placed in a bell-type furnace and aged under the protection of a mixed gas at a heating rate of 100°C / h, an aging temperature of 500°C, and a treatment time of 5h.

[0090] In the eleventh step, the aged nickel-silicon bronze strip is placed in a continuous cleaning and brushing box furnace for a second cleaning and brushing. The furnace temperature is set at 70°C, and the strip is running at 15 m / min. A 1.5% sodium hydroxide aqueous solution is sprayed on the strip surface. The strip is then brushed through a 1000-mesh and 2000-mesh non-woven fabric at a speed of 700 r / min. After being rinsed with cold and hot water, the strip is immersed in a mixture of sulfuric acid, hydrogen peroxide, and deionized water in a 1:1:2 volume ratio. The strip is then brushed again through a 1000-mesh and 2000-mesh non-woven fabric at a speed of 700 r / min. After further cold and hot water rinsing, a 0.2% benzotriazole aqueous solution is sprayed on the strip surface. The strip is then air-dried at 80°C. The strip is then finished in a stretch-bend straightening unit and a slitting unit to produce a high-strength and high-elongation nickel-silicon bronze strip.

[0091] The chemical composition of the nickel-silicon bronze strip obtained in Example 1 is shown in Table 1, and the mechanical properties are shown in Table 2.

[0092] Example 2

[0093] In the first step, the raw materials were weighed according to the chemical composition and mass percentage of the nickel-silicon bronze strip, and then the raw materials were put into a vacuum induction melting furnace and smelted at 1350°C for 180 minutes and 100 minutes respectively. After refining, the alloy solution was filtered through two stages and then cast into a water-cooled crystallizer at 1300°C. Semi-continuous casting was carried out at a casting speed of 50 mm / min and a cooling water flow rate of 12 m 3 / h, to obtain nickel-silicon bronze alloy ingots.

[0094] In the second step, the ingot is kept at 950° C. for 15 hours and then hot rolled for 7 passes. The processing rate of each pass is 14-20%, and the total processing rate is 88%, thereby obtaining a nickel-silicon bronze strip with a thickness of 18 mm.

[0095] In the third step, the nickel-silicon bronze strip is placed in a bell-type annealing furnace under argon protection, heated to 560°C at a heating rate of 140°C / h, and then kept warm for 10 hours for annealing. It is then cooled to 35°C and taken out of the furnace.

[0096] The fourth step is to mill the nickel-silicon bronze strip after it leaves the furnace. The upper and lower surfaces are milled by 0.5mm, with a tolerance of ±0.02mm, and the left and right sides are milled by 7mm, with a tolerance of ±0.02mm. It is then rough rolled in five passes, with a processing rate of 20% per pass, and then trimmed.

[0097] In the fifth step, the trimmed nickel-silicon bronze strip is loaded into a box furnace for continuous cleaning and brushing. The temperature of the box furnace is set to 60°C and the running speed of the strip is 5m / min. First, a sodium hydroxide aqueous solution with a mass concentration of 1.0% is sprayed on the surface of the strip, and then it is brushed with a 600-mesh diamond + 800-mesh alumina / nylon brush roller at a speed of 600r / min. After being rinsed with cold and hot water, it is immersed in a mixture of sulfuric acid, hydrogen peroxide and deionized water with a volume ratio of 1:1:3, and then it is brushed again with a 600-mesh diamond + 800-mesh alumina / nylon brush roller at a speed of 600r / min. After being rinsed with cold and hot water, a 0.1% benzotriazole aqueous solution is sprayed on the surface of the nickel-silicon bronze strip, and then it is blown and dried at 80°C.

[0098] In the sixth step, the cleaned and brushed strip is passed through a vertical continuous quenching furnace for a first solution treatment at 880°C under a mixed gas atmosphere at a speed of 7 m / min. The mixed gas is a combination of hydrogen and nitrogen, with the hydrogen accounting for 73%.

[0099] Step 7: Finish rolling the nickel-silicon bronze strip that has undergone the first solid solution treatment, with 4 passes and a processing rate of 20% for each pass;

[0100] In the eighth step, the nickel-silicon bronze strip, after finish rolling, passes through a vertical continuous quenching furnace for a second solution treatment at 880°C under a mixed gas atmosphere at a speed of 24 m / min. The mixed gas is hydrogen and nitrogen, with hydrogen comprising 73%.

[0101] In the ninth step, the nickel-silicon bronze strip that has undergone the second solid solution treatment is rolled into finished products, with one rolling pass and a pass processing rate of 24%.

[0102] In the tenth step, the finished rolled nickel-silicon bronze strip is placed in a bell-type furnace and aged under the protection of a mixed gas at a heating rate of 80°C / h, an aging temperature of 440°C, and a treatment time of 6h.

[0103] In the eleventh step, the aged nickel-silicon bronze strip is placed in a continuous cleaning and brushing box furnace for a second cleaning and brushing. The furnace temperature is set at 60°C, and the strip is running at 5 m / min. A 1% sodium hydroxide aqueous solution is sprayed on the strip surface. The strip is then brushed through a 1000-mesh and 2000-mesh non-woven fabric at a speed of 600 r / min. After being rinsed with cold and hot water, the strip is immersed in a mixture of sulfuric acid, hydrogen peroxide, and deionized water in a 1:1:2 volume ratio. The strip is then brushed again through a 1000-mesh and 2000-mesh non-woven fabric at a speed of 600 r / min. After further cold and hot water rinsing, a 0.1% benzotriazole aqueous solution is sprayed on the strip surface. The strip is then air-dried at 80°C. The strip is then finished in a stretch-bend straightening unit and a slitting unit to produce a high-strength and high-elongation nickel-silicon bronze strip.

[0104] The chemical composition of the nickel-silicon bronze strip obtained in Example 2 is shown in Table 1, and the mechanical properties are shown in Table 2.

[0105] Example 3

[0106] In the first step, the raw materials were weighed according to the chemical composition and mass percentage of the nickel-silicon bronze strip, and then the raw materials were put into a vacuum induction melting furnace and smelted at 1390°C for 100 minutes and 60 minutes. After refining, the alloy solution was filtered through two stages and then cast into a water-cooled crystallizer at 1350°C. Semi-continuous casting was carried out at a casting speed of 110 mm / min and a cooling water flow rate of 16 m 3 / h, to obtain nickel-silicon bronze alloy ingots.

[0107] In the second step, the ingot is kept at 980° C. for 6 hours and then hot rolled for 9 passes. The processing rate of each pass is 24-28%, and the total processing rate is 92%, thereby obtaining a nickel-silicon bronze strip with a thickness of 16 mm.

[0108] In the third step, the nickel-silicon bronze strip is placed in a bell-type annealing furnace under argon protection, heated to 600°C at a heating rate of 170°C / h, and then kept warm for 7 hours for annealing. It is then cooled to 35°C and taken out of the furnace.

[0109] The fourth step is to mill the nickel-silicon bronze strip after it leaves the furnace. The upper and lower surfaces are milled to 0.3mm each, with a tolerance of ±0.02mm, and the left and right sides are milled to 5mm each, with a tolerance of ±0.02mm. The strip is then rough rolled in seven passes, with a processing rate of 12% per pass, followed by trimming.

[0110] The fifth step is to load the trimmed nickel-silicon bronze strip into a box furnace for continuous cleaning and brushing, set the temperature of the box furnace to 80°C, and the running speed of the strip to 25m / min. First, a sodium hydroxide aqueous solution with a mass concentration of 2.0% is sprayed on the surface of the strip, and then it is brushed with a 600-mesh diamond + 800-mesh alumina / nylon brush roller at a speed of 800r / min. After being rinsed with cold and hot water, it is immersed in a mixture of sulfuric acid, hydrogen peroxide and deionized water with a volume ratio of 1:1:3, and then it is brushed again with a 600-mesh diamond + 800-mesh alumina / nylon brush roller at a speed of 800r / min. After being rinsed with cold and hot water, a 0.3% benzotriazole aqueous solution is sprayed on the surface of the nickel-silicon bronze strip, and then it is blown and dried at 80°C.

[0111] In the sixth step, the cleaned and brushed strip is passed through a vertical continuous quenching furnace for a first solution treatment at 910°C under a mixed gas atmosphere at a speed of 23 m / min. The mixed gas is a mixture of hydrogen and nitrogen, with the hydrogen accounting for 75%.

[0112] Step 7: Finish rolling the nickel-silicon bronze strip that has undergone the first solid solution treatment for 3 passes, with a processing rate of 28% per pass;

[0113] In the eighth step, the nickel-silicon bronze strip, after finish rolling, passes through a vertical continuous quenching furnace for a second solution treatment at 910°C under a mixed gas atmosphere at a speed of 40 m / min. The mixed gas is hydrogen and nitrogen, with hydrogen accounting for 75%.

[0114] In the ninth step, the nickel-silicon bronze strip that has undergone the second solid solution treatment is rolled into finished products, with three rolling passes and a pass processing rate of 18%.

[0115] In the tenth step, the finished rolled nickel-silicon bronze strip is placed in a bell-type furnace and aged under the protection of a mixed gas at a heating rate of 120°C / h, an aging temperature of 540°C, and a treatment time of 4h.

[0116] In the eleventh step, the aged nickel-silicon bronze strip is placed in a continuous cleaning and brushing box furnace for a second cleaning and brushing. The furnace temperature is set at 80°C, and the strip is running at 25 m / min. A 2.0% sodium hydroxide aqueous solution is sprayed on the strip surface. The strip is then brushed through a 1000-mesh and 2000-mesh non-woven fabric at a speed of 800 r / min. After being rinsed with cold and hot water, the strip is immersed in a mixture of sulfuric acid, hydrogen peroxide, and deionized water in a 1:1:2 volume ratio. The strip is then brushed again through a 1000-mesh and 2000-mesh non-woven fabric at a speed of 800 r / min. After further cold and hot water rinsing, a 0.3% benzotriazole aqueous solution is sprayed on the strip surface. The strip is then air-dried at 80°C. The strip is then finished in a stretch-bend straightening unit and a slitting unit to produce a high-strength and high-elongation nickel-silicon bronze strip.

[0117] The chemical composition of the nickel-silicon bronze strip obtained in Example 3 is shown in Table 1, and the mechanical properties are shown in Table 2.

[0118] Table 1

[0119]

[0120] Fe, Zn, Mn, Pb, and Al in Table 1 are unavoidable impurities.

[0121] Table 2

[0122]

[0123] In summary, the solution proposed in the present invention has the following technical effects:

[0124] The present invention firstly obtains an ingot through melting, refining, two-stage filtration, casting and semi-continuous casting according to the composition of nickel-silicon bronze. Subsequently, the ingot is subjected to processes such as hot rolling after heating, annealing, surface milling, rough rolling, first cleaning and brushing, first solid solution, finish rolling, second solid solution, finished product rolling, aging, second cleaning and brushing, straightening and slitting to obtain a nickel-silicon bronze strip. The problem of surface oxidation of the strip is solved, and the surface and internal quality of the strip are improved. While improving the strength and elongation of the strip, the yield of the strip is also increased, which can meet the needs of mass production of large-volume heavy nickel-silicon bronze strip.

[0125] The above embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A method for preparing a high-strength and high-elongation nickel-silicon bronze strip, characterized in that: The preparation method comprises: Step S1, weighing raw materials according to the chemical composition and mass percentage of the nickel-silicon bronze strip, and sequentially performing smelting, refining, two-stage filtration, casting and semi-continuous casting on the raw materials to obtain an ingot; The chemical composition and mass percentage of the nickel-silicon bronze strip are as follows: Ni: 2.2-4.0%, Si: 0.5-0.90%, Mg: 0.05-0.30%, and the balance is Cu and unavoidable impurities; Step S2, holding the ingot at 950-980° C. for 6-15 hours and then hot rolling to obtain a strip with a thickness of 16-18 mm; Step S3, annealing the strip under inert gas protection, and then cooling it to 35°C before taking it out of the furnace; the annealing temperature is increased at a rate of 140-170°C / h, the temperature is 560-600°C, and the holding time is 7-10h; Step S4, sequentially performing milling, rough rolling, edge trimming and first cleaning and brushing on the annealed strip; The degreasing agent for the first cleaning and brushing is a sodium hydroxide aqueous solution with a mass concentration of 1-2%, the pickling agent for the first cleaning and brushing is a mixture of sulfuric acid, hydrogen peroxide and deionized water in a volume ratio of 1:1:3, and the passivating liquid for the first cleaning and brushing is a benzotriazole aqueous solution with a mass concentration of 0.1-0.3%; Step S5, subjecting the strip that has undergone the first cleaning and brushing to a first solution treatment under the protection of a mixed gas; the temperature of the first solution treatment is 880-910° C., and the strip speed is 7-23 m / min; Step S6, finishing rolling the strip after the first solution treatment; Step S7, subjecting the finish-rolled strip to a second solid solution treatment under the protection of a mixed gas; the second solid solution treatment temperature is 880-910° C., and the strip speed is 24-40 m / min; Step S8, rolling the finished strip after the second solution treatment and then aging it, then cooling it to 40°C and then taking it out of the furnace; the aging heating rate is 80-120°C / h, the temperature is 440-540°C, and the holding time is 4-6h; Step S9, sequentially cleaning, brushing, straightening, and slitting the aged strip to obtain a nickel-silicon bronze strip; The degreasing agent for the second cleaning and brushing is a sodium hydroxide aqueous solution with a mass concentration of 1-2%, the pickling agent for the second cleaning and brushing is a mixture of sulfuric acid, hydrogen peroxide and deionized water with a volume ratio of 1:1:2, and the passivating liquid for the second cleaning and brushing is a benzotriazole aqueous solution with a mass concentration of 0.1-0.3%.

2. The preparation method according to claim 1, characterized in that In the step S1, the smelting temperature is 1350-1390° C., and the time is 100-180 min; and the refining time is 60-100 min.

3. The preparation method according to claim 1, characterized in that In the step S1, the casting temperature is 1300-1350°C.

4. The preparation method according to claim 1, characterized in that In step S1, the semi-continuous casting speed is 50-110 mm / min, and the cooling water flow rate is 12-16 m / min. 3 / h.

5. The preparation method according to claim 1, characterized in that In step S2, the hot rolling is performed in 7-9 passes, the processing rate of each pass is 14-28%, and the total processing rate is 88-92%.

6. The preparation method according to claim 1, characterized in that In the step S4, the rough rolling is performed 5-7 times, and the processing rate of each time is 12-20%.

7. The preparation method according to claim 1, characterized in that In step S4 or step S9, the first cleaning and brushing or the second cleaning and brushing is carried out in a box furnace for continuous cleaning and brushing, the temperature of the box furnace is 60-80°C, the belt speed is 5-25m / min, and the speed of the brush roller is 600-800r / min.

8. The preparation method according to claim 1, characterized in that In step S6, the number of passes of the finish rolling is 3-4, and the processing rate of each pass is 20-28%.

9. The preparation method according to claim 1, characterized in that In step S8, the number of passes for rolling the finished product is 1-3, and the processing rate of each pass is 18-24%.

10. A high-strength and high-elongation nickel-silicon bronze strip, characterized in that: The nickel-silicon bronze strip is prepared by the preparation method according to any one of claims 1 to 9.

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