Wide-width high-nickel cupronickel thin soft strip and preparation method thereof

Abstract

The invention provides a wide-width high-nickel cupronickel thin soft strip and a preparation method. The wide-width high-nickel cupronickel thin soft strip comprises the following components in percentage by mass: 30.0-32.0% of Ni, 0.6-1.0% of Fe, 0.6-1.0% of Mn, less than 0.03% of C, less than 0.01% of S, less than 0.01% of P, less than 0.01% of Pb, less than 0.01% of Zn, less than 0.01% of Si, less than 0.01% of Sn, less than or equal to 0.3% of impurities and the balance of Cu. The preparation method comprises the steps of component design, smelting, casting, saw cutting, primary heating, primary hot rolling, secondary heating, secondary hot rolling, surface milling, rough rolling, trimming, bell furnace annealing heat treatment, primary finish rolling, primary air cushion furnace annealing heat treatment, secondary finish rolling, secondary air cushion furnace annealing heat treatment and finished product detection. The thickness of the high-nickel cupronickel finished thin soft belt prepared by the preparation method is 0.3-1.0 mm, the width is larger than or equal to 620 mm, and the high-nickel cupronickel finished thin soft belt is stable in performance, good in extension performance, good in corrosion resistance and capable of meeting use requirements.

Description

Technical Field

[0001] The invention relates to the field of nonferrous metal smelting and processing, and in particular to a wide high-nickel copper-white thin soft strip and a preparation method thereof. Background Art

[0002] In recent years, China has continuously made new breakthroughs in the research and development and construction of high-tech ships and marine engineering equipment, and the demand for corrosion-resistant copper alloys for the required piping systems has increased significantly. The equipment on the piping system will produce large instantaneous displacements due to the impact of seawater, which may cause pipeline damage in severe cases. The corrugated flexible pipe is a pressure-bearing elastic compensation device that relies on pipe expansion joints to compensate for displacement and prevent leakage and deformation. The elastic compensation pipe made of high-nickel white copper thin soft strip is adopted because of its strong corrosion resistance.

[0003] The design of this elastic compensation tube is to use high-nickel white copper soft strip with a thickness of 0.3-1.0mm and a circumference of ≥620mm, weld it into a straight tube and then press it into a wavy pattern. This requires the production of high-nickel white copper finished thin soft strip with a width of ≥620mm, stable performance and good elongation. At present, the national standards GB / T5231 "Chemical Composition and Product Shape of Processed Copper and Copper Alloys" and GB / T2059 "Copper and Copper Alloy Strips" cover the chemical composition, mechanical properties and other requirements of 0.15-1.2mm thin strips, but the width limit range is ≤400mm, which cannot meet the unfolding width requirements of the tube; the elongation after fracture is ≥23%, and when this soft strip is formed again, the elongation after fracture is not less than 36% to be guaranteed. However, for this wide high-nickel white copper thin soft strip, whether it is ingot casting or hot rolling and subsequent processing, key process technologies need to be broken through. Summary of the invention

[0004] The present invention aims to provide a wide high-nickel white copper thin soft strip and a preparation method thereof. The high-nickel white copper finished thin soft strip prepared by the preparation method of the present invention has a thickness of 0.3-1.0 mm and a width of ≥620 mm, stable performance, good elongation performance, good corrosion resistance, and can meet use requirements.

[0005] In order to achieve the above object, the specific scheme adopted by the present invention is: On the one hand, the present invention provides a method for preparing a wide high-nickel white copper thin soft strip, wherein the wide high-nickel white copper thin soft strip has a thickness of 0.3-1.0 mm and a width of ≥620 mm, and the composition thereof comprises, by mass percentage, the following: Ni 30.0-32.0%, Fe 0.6-1.0%, Mn 0.6-1.0%, C <0.03%, S <0.01%, P <0.01%, Pb <0.01%, Zn <0.01%, Si <0.01%, Sn <0.01%, the total amount of impurities ≤0.3, and the remainder is Cu; The preparation method comprises the following steps: S1, weighing raw materials, adding the raw materials into the furnace for melting, and the copper liquid is exposed during the melting process; S2. After the copper in the furnace is fully liquefied, add calcined charcoal to cover it; adjust the content of the main component elements to the range of discharge; S3. After the copper liquid has qualified components, the temperature is raised and copper and magnesium are added in a certain proportion for deoxidation; S4. After deoxidation is completed, a high-amplitude ingot casting system and a crystallizer are used for casting to obtain an ingot; S5, sawing the ingot obtained in S4 to obtain an ingot of required length; S6, heating the ingot once in a heating furnace, the heating temperature is 950-1080°C, the heating time is 3.0-5.0 hours, and the ingot is evenly heated and then taken out of the furnace; after the ingot is heated and taken out of the furnace, hot rolling is performed once; the processing rate of the hot rolling strip is 60-75%, the number of passes is 8, and the final rolling temperature is not less than 850°C; S7, after the hot-rolled strip is cooled, it is heated again at a temperature of 950-980°C for 3-4.5 hours. After the ingot is evenly heated, it is taken out of the furnace and hot-rolled to the milling thickness, with a processing rate greater than 75%, and hot-rolled to the milling thickness to obtain a hot-rolled strip coil; S8, milling the hot-rolled coil, rough rolling the blank to 2.0-2.4 mm, trimming the edges, and annealing the hot-rolled coil in a bell furnace at a temperature of 620° C. for 6 hours; S9, performing a finish rolling on the strip coil obtained by the process in S8, and finishing rolling the strip coil to a thickness 1.5 to 2.0 times that of the finished product; S10, performing an air cushion furnace annealing heat treatment on the rolled strip, the annealing temperature is 720-800°C, the speed is 8-20m / min, a protective atmosphere is used during the annealing, the gas content is: 75% hydrogen, the rest is nitrogen; S11, performing secondary finish rolling on the annealed strip to the finished product thickness; S12, performing secondary air cushion furnace annealing heat treatment on the rolled strip, the annealing temperature is 720-800°C, the speed is 8-20m / min, and a protective atmosphere is used during annealing, the gas content is: 75% hydrogen, and the rest is nitrogen; S13. The qualified finished strips are cut, packaged and stored according to the required specifications.

[0006] Furthermore, in step S1, the raw materials are old materials and / or new materials. When it is new material, Cu is added in the form of standard copper, Fe is added in the form of iron sheets, Mn is added in the form of electrolytic manganese, and Ni is added in the form of electrolytic nickel.

[0007] Furthermore, in step S3, the amount of copper and magnesium added is 0.05-0.1% of the weight of the copper liquid.

[0008] Furthermore, in step S4, a high-amplitude ingot casting system is provided in a crystallizer, including a crucible and a casting tube with one end vertically extending into the crucible, and two through holes are relatively provided on the side wall of the crucible. The molten copper enters the crucible from the casting tube, and then flows into the crystallizer through the through holes. In the crystallizer, the molten copper is cooled, solidified and crystallized by the cooling water in the crystallizer cavity, and is pulled downward by the ingot guide support to continuously perform casting.

[0009] Furthermore, the material of the pouring tube is SiC or SiC composite material, and the material of the crucible is clay.

[0010] On the other hand, the present invention provides a wide high-nickel copper-white thin soft strip, which is prepared by the above method.

[0011] Furthermore, the wide high-nickel white copper thin soft strip has a tensile strength of 400-425 MPa, a yield strength of 170-200 MPa, an elongation of 38-42%, and a grain size of 0.01-0.02 mm.

[0012] Beneficial effects: (1) The high-nickel nickel silver designed by the present invention reduces the range of the main components, especially the nickel content, so that the strip performance is more stable, the content of impurity elements that are easily corroded by seawater is strictly controlled, and the application performance of the strip is improved; through the redox process technology combined with the innovative improvement of the high-width ingot casting system, the impurity carbon is effectively controlled, and the quality of the wide-width high-nickel nickel silver ingot is effectively guaranteed; through two hot rolling billets, the quality of the high-strength wide-width high-nickel nickel silver strip curling is improved; the air cushion furnace annealing process is adopted, which not only solves the problem of easy burning and sticking of the wide-width high-nickel nickel silver strip, but also improves and guarantees the uniformity of the material performance.

[0013] (2) The wide high-nickel white copper thin soft strip prepared by the method of the present invention has a tensile strength of 400-425 MPa, a yield strength of 170-200 MPa, an elongation of 38-42%, a grain size of 0.01-0.02 mm, stable performance, good elongation performance, good corrosion resistance, and can meet the use requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic structural diagram of the high-amplitude ingot casting system of the present invention.

[0015] Graphic markings: 1. pouring tube, 2. crucible, 201. through hole, 3. crystallizer. DETAILED DESCRIPTION

[0016] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0017] It should be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0018] The present invention provides a wide high-nickel copper-white thin soft strip and a preparation method thereof, and the preparation method comprises: composition design-melting-casting-sawing-primary heating-primary hot rolling-secondary heating-secondary hot rolling-milling, rough rolling, trimming, bell furnace annealing heat treatment-primary finishing rolling-primary air cushion furnace annealing heat treatment-secondary finishing rolling-secondary air cushion furnace annealing heat treatment-finished product inspection. In order to obtain a copper soft strip with a thickness of 0.3-1.0 mm, a width of ≥620 mm, stable performance, good elongation performance, and good corrosion resistance, the present invention optimizes the following aspects.

[0019] 1. Optimized design of wide-width high-nickel copper-nickel alloy composition The composition of copper-nickel alloy plays a key role in the processing performance, mechanical properties and corrosion resistance of pipes. According to theoretical research results, the increase in nickel content can not only increase the strength of the material, but also help improve the corrosion resistance of the material; when the nickel content in white copper is above 30% and the iron content is above 0.5%, the seawater erosion corrosion resistance is significantly improved, but the iron content generally does not exceed 2%. Manganese can significantly improve the resistance to turbulent impact corrosion. The present invention optimizes the element range of the main component elements nickel, iron and manganese, making the strip performance more stable and the service performance will also be improved accordingly.

[0020] At the same time, by controlling the content of harmful impurities in high-nickel white copper, it helps to improve the comprehensive performance of the strip. The present invention theoretically analyzes the influence of impurity elements: carbon elements will be enriched at the grain boundaries or distributed in the grains in a free state, which is easy to promote grain boundary corrosion and pitting corrosion of the material; sulfur elements will precipitate gray NiS strips along the grain boundaries, causing hot cracking and cold brittleness during the processing process, and significantly reducing welding performance; phosphorus elements have adverse effects on its processing performance and corrosion resistance. Combined with engineering preparation technology, the content of carbon, sulfur and phosphorus is strictly controlled.

[0021] The components of the wide high-nickel white copper thin soft strip in the present invention include, by mass percentage, Ni 30.0-32.0%, Fe 0.6-1.0%, Mn 0.6-1.0%, C <0.03%, S <0.01%, P <0.01%, Pb <0.01%, Zn <0.01%, Si <0.01%, Sn <0.01%, the total amount of impurities is ≤0.3, and the balance is Cu.

[0022] 2. Production method of wide high nickel white copper ingot In the case of high-temperature smelting without vacuum, in order to reduce the reaction between copper liquid and furnace gas or absorb dissolved harmful gases, the best protective covering agent is charcoal. While the C in charcoal protects and deoxidizes the copper liquid, it will inevitably react with nickel, Ni+C= Ni2C, making the copper liquid easy to absorb C. At the same time, conventional copper and copper alloy casting systems use graphite products, which have good processing performance and deoxidize copper liquid. However, the carbon element contained in the charcoal is very easy to react with the nickel in the copper liquid, which not only increases the carbon content of the copper liquid, but also makes the casting process unable to control the flow casting due to tool damage.

[0023] It has been found in practice that in the reduction process commonly used in the smelting of copper and copper alloys, the copper liquid is always covered and protected by charcoal. Although the quality of the copper liquid is guaranteed, for high-nickel white copper, even if all new metals are used for production, the carbon content of the copper liquid is very easy to reach the upper limit or even exceed the standard. It is even more difficult to control the carbon content when using old materials of this brand for production, resulting in the long-term backlog of old materials of this brand that cannot be used. The oxidation-reduction process is used to oxidize the copper liquid during the smelting process. The impurity carbon will react with the oxygen in the air to remove it, and then charcoal is used in combination with copper and magnesium to quickly remove the excess oxygen in the copper liquid, so that the carbon in the copper liquid can be kept at a low level without affecting the quality.

[0024] The graphite products used in the casting system can be replaced by SiC or SiC composite materials, but both materials cannot be machined. For such high-nickel white copper ingots whose width is more than 3 times the thickness, straight tube casting obviously cannot meet the relatively uniform distribution of the temperature field in the crystallizer. Therefore, the present invention designs a new wide-width ingot casting system, such as Figure 1 As shown, it includes a pouring tube 1 made of SiC or SiC composite material and a crucible 2 made of clay, wherein the crucible 2 is placed on the upper part of the crystallizer 3, the pouring tube 1 is vertically installed in the crucible 2, and two through holes 201 are relatively arranged on the inner wall of the lower part of the crucible 2. The use of this pouring system can not only reduce the chance of carbon entering the copper liquid, but also effectively adjust the temperature field in the crystallizer, so that the casting process can proceed smoothly.

[0025] like Figure 1As shown, the copper liquid enters the wide ingot casting system composed of a pouring pipe 1 and a crucible 2. The copper liquid has no chance to contact the carbonaceous material. After secondary distribution in the crucible 2, it is easier to flow to the far end of the wide crystallizer 3, while avoiding the copper liquid at the far end. The temperature is too low and the casting quality is difficult to ensure. After solidification and crystallization in the crystallizer 3, it is pulled down by the ingot holder (not shown in the figure) and continuously cast. During this process, the surface of the copper liquid is covered with a covering agent. The size of the crucible can be adjusted according to the width of the casting crystallizer 3.

[0026] 3. Processing method of wide high nickel white copper thin soft strip Wide width high nickel white copper has a high temperature for hot rolling. Once the temperature drops during hot rolling, its deformation resistance increases rapidly. The hot rolled blank is prone to cracking, resulting in the width of the final product failing to meet the use requirements.

[0027] It has been found in practice that the method of rolling twice during hot rolling can effectively ensure the edge quality of wide strip.

[0028] There are two annealing methods in the processing of copper and copper alloy strips: bell furnace annealing and air cushion furnace annealing. The bell furnace annealing coils are stacked one by one. The thinner the strip and the higher the temperature, the easier it is for the layers to stick together during annealing. When the width of the strip increases, the deadweight makes it easier for the edge to be stressed, and bonding is more likely to occur. High-nickel white copper has poor thermal conductivity, and bell furnace annealing requires higher temperatures and longer times to make the performance of the strip uniform. When annealing in an air cushion furnace, a single layer of thin strip passes through a heating furnace. Under the condition of a suitable annealing process, all parts of the strip are heated at the same time, and the heating time is the same, so the structure will be more uniform.

[0029] It has been found in practice that wide high-nickel white copper thin soft strip is more suitable for air cushion furnace annealing, the grain size of the strip is uniform and the elongation performance is good.

[0030] The present invention designs a better preparation method by optimizing the above-mentioned various parts, which is specifically as follows: S1. Add the surface-dried standard copper, iron sheet, electrolytic manganese or the waste material weighed according to the above ratio into the furnace for melting, and the copper liquid is exposed during the melting process; S2. After the copper in the furnace is fully liquefied, add calcined charcoal to cover it; adjust the content of the main component elements to the range of discharge; S3. After the ingredients are qualified, the temperature is raised and copper and magnesium are added in a certain proportion for deoxidation; S4. After deoxidation is completed, a high-amplitude ingot casting system and a crystallizer are used for casting to obtain an ingot; S5, sawing the ingot obtained in S4 to obtain an ingot of required length; S6, heating the ingot once in a heating furnace, the heating temperature is 950-1080°C, the heating time is 3.0-5.0 hours, and the ingot is evenly heated and then taken out of the furnace; after the ingot is heated and taken out of the furnace, hot rolling is performed once; the processing rate of the hot rolling strip is 60-75%, the number of passes is 8, and the final rolling temperature is not less than 850°C; S7, after the hot-rolled strip is cooled, it is heated again at a temperature of 950-980°C for 3-4.5 hours. After the ingot is evenly heated, it is taken out of the furnace and hot-rolled to the milling thickness, with a processing rate greater than 75%, and hot-rolled to the milling thickness to obtain a hot-rolled strip coil; S8, milling the hot-rolled coil, rough rolling the blank to 2.0-2.4 mm, trimming the edges, and annealing the hot-rolled coil in a bell furnace at a temperature of 620° C. for 6 hours; S9, performing a finish rolling on the strip coil obtained by the process in S8, and finishing rolling the strip coil to a thickness 1.5 to 2.0 times that of the finished product; S10, performing an air cushion furnace annealing heat treatment on the rolled strip, the annealing temperature is 720-800°C, the speed is 8-20m / min, a protective atmosphere is used during the annealing, the gas content is: 75% hydrogen, the rest is nitrogen; S11, performing secondary finish rolling on the annealed strip to the finished product thickness; S12, performing secondary air cushion furnace annealing heat treatment on the rolled strip, the annealing temperature is 720-800°C, the speed is 8-20m / min, and a protective atmosphere is used during annealing, the gas content is: 75% hydrogen, and the rest is nitrogen; S13. The qualified finished strips are cut, packaged and stored according to the required specifications.

[0031] Example 1 A soft strip of high nickel white copper with a specification of 0.3×630mm and good surface and internal quality is produced.

[0032] The technical requirements are: State: soft state (M); Performance requirements: tensile strength Rm ≥ 370MPa, yield strength Rp0.2 ≥ 138Mpa, elongation A11.3 ≥ 35%, grain size 0.005 ~ 0.025mm; The preparation process adopted is as follows: 1) Ingredients: including 50% new material and 50% BFe30-1-1 old material, in which Cu is added in the form of standard copper, Fe is added in the form of iron flakes, Ni is added in the form of electrolytic nickel, and Mn is added in the form of electrolytic manganese; weigh the raw materials, add the raw materials into the furnace for melting; it should be noted that in industrial production, due to the addition of BFe30-1-1 old material, the accuracy of the ingredient weight and the different operations of the operators during smelting are different, resulting in slight differences in the components of the products in each embodiment; 2) Smelting: During the melting process, the copper liquid is exposed; after the copper liquid in the furnace is full, add calcined charcoal to cover it; adjust the content of the main component elements to reach the range of the furnace; 3) Adjust the composition and deoxidation: After the composition is qualified, increase the temperature and add copper and magnesium for deoxidation in a certain proportion; 4) Casting: After deoxidation, high-amplitude ingot casting system and crystallizer are used for casting, and the required length of the production plan is achieved; 5) Sawing: sawing the obtained ingot according to the required length on a sawing machine; 6) One-time hot rolling: The sawn ingot is heated once in a heating furnace, the heating temperature is 1050°C, the heating time is 5.0 hours, and the ingot is evenly heated and taken out of the furnace; the ingot is hot rolled once after being heated and taken out of the furnace, the processing rate of the hot rolled strip is 61.9%, the total number of passes is 8, and the final rolling temperature is not less than 850°C; 7) Secondary hot rolling: After the hot-rolled strip is cooled, it is heated again at a temperature of 980°C for 4.5 hours. After the ingot is evenly heated, it is taken out of the furnace for secondary hot rolling to the milling thickness, with a processing rate of 82.5%; 8) Milling, rough rolling, trimming and bell furnace annealing: The hot rolled coils are milled, rough rolled to 2.0 mm, trimmed, and annealed in a bell furnace (annealing process: 620°C for 5 hours and 6 hours); 9) Primary finishing rolling: The strip coil obtained after bell furnace annealing is subjected to primary finishing rolling to a thickness 1.6 times that of the finished product; 10) One-time air cushion furnace annealing: The strip after rolling 1 is subjected to one-time air cushion furnace annealing heat treatment, the annealing temperature is 740°C, the speed is 18m / min, and a protective atmosphere is used during annealing, the gas content is: hydrogen 75%, the rest is nitrogen; 11) Secondary finishing rolling: The annealed strip is rolled to a finished product thickness of 0.3 mm; 12) Secondary air cushion furnace annealing: The strip after rolling 2 is subjected to air cushion furnace annealing heat treatment, the annealing temperature is 720°C, the speed is 20m / min, and a protective atmosphere is used during annealing, the gas content is: hydrogen 75%, the rest is nitrogen; 13) Finished product inspection and shearing: Take mechanical properties and grain size samples of the strip, make the samples according to the standards, and then use electronic tensile testing machine and electron microscope for inspection. After the mechanical properties and grain size meet the requirements, the finished product is sheared. After the finished product passes the inspection, it is packaged and put into storage.

[0033] In Example 1, sampling and testing were performed, and the proportions of the components were as follows: Ni 30.48%, Fe 0.81%, Mn 0.63%, C0.0082%, S<0.01%, P <0.01%, Pb <0.01%, Zn <0.01%, Si <0.01%, Sn <0.01%, and the balance was Cu. The tensile strength Rm was 401MPa, the yield strength Rp0.2 was 176Mpa, the elongation A11.3 was 40%, and the grain size was 0.010mm; the mechanical properties of the prepared product met the performance requirements of the design.

[0034] Example 2 A soft strip of high nickel white copper with a specification of 0.5×630mm and good surface and internal quality is produced.

[0035] The difference between its preparation process and Example 1 is that in step 1), 100% BFe30-1-1 old material is used as the ingredients. In step 6), the primary heating temperature is 1080°C and the holding time is 4.8 hours; the primary hot rolling strip processing rate is 62.9%. In step 7), the secondary heating temperature is 980°C and the holding time is 4 hours; the primary hot rolling strip processing rate is 82.1%. In step 10), the annealing process is 800°C and the speed is 12m / min. In step 12), the annealing process is 740°C and the speed is 18m / min.

[0036] In Example 2, sampling and testing were performed, and the proportions of the components were as follows: Ni 30.91%, Fe 0.89%, Mn 0.92%, C0.0093%, S<0.01%, P <0.01%, Pb <0.01%, Zn <0.01%, Si <0.01%, Sn <0.01%, and the balance was Cu. The tensile strength Rm was 407MPa, the yield strength Rp0.2 was 172Mpa, the elongation A11.3 was 38%, and the grain size was 0.010mm; the mechanical properties of the prepared product met the performance requirements of the design.

[0037] Example 3 A soft strip of high nickel white copper with a specification of 0.8×630mm and good surface and internal quality is produced.

[0038] The difference between its preparation process and Example 1 is that: in step 1), the ingredients are 30% new material + 70% BFe30-1-1 old material. In step 6), the primary heating temperature is 1050°C and the holding time is 5.0 hours; the processing rate of the hot-rolled strip is 65.2%. In step 7), the secondary heating temperature is 950°C and the holding time is 4 hours; the processing rate of the hot-rolled strip is 80.8%. In step 8), the hot-rolled strip is milled, roughly rolled to 2.4mm, trimmed, and annealed in a bell furnace (annealing process: 620°C plus 5H and 6H). In step 9), the strip obtained after annealing in the bell furnace is subjected to a finish rolling, which is 1.8 times the thickness of the finished product. In step 10), the annealing process is 800°C and the speed is 8m / min. In step 12), the annealing process is 780°C and the speed is 15m / min.

[0039] In Example 3, sampling and testing were performed, and the proportions of the components were as follows: Ni 30.83%, Fe 0.75%, Mn 0.80%, C0.0012%, S<0.01%, P <0.01%, Pb <0.01%, Zn <0.01%, Si <0.01%, Sn <0.01%, and the balance was Cu. The tensile strength Rm was 423MPa, the yield strength Rp0.2 was 185Mpa, the elongation A11.3 was 40.5%, and the grain size was 0.015mm; the mechanical properties of the prepared product met the performance requirements of the design.

[0040] Example 4 A soft strip of high nickel white copper with a specification of 1.0×630mm and good surface and internal quality is produced.

[0041] The difference between its preparation process and Example 1 is that: in step 1), the ingredients are 40% new material + 60% BFe30-1-1 old material. In step 6), the primary heating temperature is 1080°C, the holding time is 4.8 hours; the processing rate of the hot-rolled strip is 68.1%. In step 7), the secondary heating temperature is 950°C, the holding time is 3.5 hours; the processing rate of the hot-rolled strip is 79.1%. In step 8), the hot-rolled strip is milled, the rough rolling is opened to 2.4mm, the edges are trimmed, and the bell furnace is annealed (annealing process: 620°C plus 5H and 6H). In step 9), the strip obtained after annealing in the bell furnace is subjected to a finish rolling, and the finish rolling is 1.5 times the thickness of the finished product. In step 10), the annealing process is 800°C and the speed is 8m / min. In step 12), the annealing process is 800°C and the speed is 12m / min.

[0042] In Example 4, sampling and testing were performed, and the proportions of the components were as follows: Ni 31.92%, Fe 0.64%, Mn 0.78%, C0.015%, S<0.01%, P <0.01%, Pb <0.01%, Zn <0.01%, Si <0.01%, Sn <0.01%, and the balance was Cu. The tensile strength Rm was 421MPa, the yield strength Rp0.2 was 195Mpa, the elongation A11.3 was 41%, and the grain size was 0.02mm; the mechanical properties of the prepared product met the performance requirements of the design.

[0043] Example 5 A soft strip of high nickel white copper with a specification of 0.5×630mm and good surface and internal quality is produced.

[0044] The difference between its preparation process and Example 1 is that in step 1), 100% new material is used as the ingredients. In step 6), the primary heating temperature is 1050°C and the holding time is 5.0 hours; the processing rate of the hot-rolled strip is 71.4%. In step 7), the secondary heating temperature is 950°C and the holding time is 3.0 hours; the processing rate of the hot-rolled strip is 76.7%. In step 10), the annealing process is 800°C and the speed is 12m / min. In step 12), the annealing process is 740°C and the speed is 18m / min.

[0045] In Example 5, sampling and testing were performed, and the proportions of the components were as follows: Ni 31.54%, Fe 0.90%, Mn 0.87%, C0.023%, S<0.01%, P <0.01%, Pb <0.01%, Zn <0.01%, Si <0.01%, Sn <0.01%, and the balance was Cu. The tensile strength Rm was 418MPa, the yield strength Rp0.2 was 189Mpa, the elongation A11.3 was 39.5%, and the grain size was 0.015mm; the mechanical properties of the prepared product met the performance requirements of the design.

[0046] Comparative Example 1 A soft strip of high nickel white copper with a specification of 0.3×630mm and good surface and internal quality is produced.

[0047] The difference from Example 1 is that in step 1), 100% of BFe30-1-1 old material is used as the ingredient.

[0048] Comparative Example 1 was sampled and tested, and the proportions of the components were as follows: Ni 29.3%, Fe 0.81%, Mn 0.78%, C0.0078%, S<0.01%, P <0.01%, Pb <0.01%, Zn <0.01%, Si <0.01%, Sn <0.01%, and the balance was Cu. The tensile strength Rm was 373MPa, the yield strength Rp0.2 was 128Mpa, the elongation A11.3 was 34%, and the grain size was 0.015mm; the mechanical properties of the prepared product, tensile and elongation, met the performance requirements of the national standard BFe30-1-1, but the performance was slightly lower than the performance requirements of the patented design.

[0049] Comparative Example 2 A soft strip of high nickel white copper with a specification of 0.5×630mm and good surface and internal quality is produced.

[0050] The difference from Example 1 is that: in step 1), 100% new materials are used. In step 2), calcined charcoal is added after the raw materials are put into the furnace, and calcined charcoal is added during the smelting process to ensure that the copper liquid is well covered and not exposed as much as possible; Comparative Example 2 Sampling and testing of chemical composition: Ni 31.48%, Fe 0.89%, Mn 0.93%, C 0.056%, S < 0.01%, P < 0.01%, Pb < 0.01%, Zn < 0.01%, Si < 0.01%, Sn < 0.01%, the balance is Cu. The impurity carbon content of the prepared ingot not only exceeds the design requirements of the present invention, but also exceeds the requirements of the national standard BFe30~1~1, and the ingot is scrapped. No further processing is carried out.

[0051] Comparative Example 3 A soft strip of high nickel white copper with a specification of 0.8×630mm and good surface and internal quality is produced.

[0052] The difference from Example 1 is that this pouring system uses a traditional straight graphite tube for pouring. When the casting length reaches 0.8 meters, the flow control plug is oxidized and cannot stably control the flow, the pouring tube wall is oxidized and damaged, the liquid level cannot be controlled, and the casting is terminated.

[0053] Comparative Example 3 Sampling and testing of chemical composition: Ni 30.83%, Fe 0.73%, Mn 0.75%, C 0.04%, S <0.01%, P <0.01%, Pb <0.01%, Zn <0.01%, Si <0.01%, Sn <0.01%, the balance is Cu. The use of graphite casting system tools, due to the fast reaction with nickel in high-nickel white copper at high temperature, makes the carbon content of the impurities in the prepared ingot exceed the upper limit of C in the national standard BFe30-1-1, and also cannot meet the service life requirements of the casting process of high-nickel white copper wide ingot.

[0054] Comparative Example 4 A soft strip of high nickel white copper with a specification of 1.0×630mm and good surface and internal quality is produced.

[0055] The difference from Example 1 is that: in step 1), the ingredients are 30% new material + 70% BFe30-1-1 old material; in step 6), the primary heating temperature is 1080°C and the holding time is 4.8 hours; the primary hot rolling strip processing rate is 92.1%. Step 7 is not included). In step 10), the annealing process is 780°C and the speed is 12m / min. In step 12), the annealing process is 780°C and the speed is 10m / min.

[0056] In comparative example 4, when the hot rolling was performed to a millable thickness, the edges of the hot rolled strip were cracked and pressed together. After trimming and processing to the finished product, the width of the strip was less than 586 mm, which did not meet the use requirements.

[0057] Sampling and testing: Chemical composition: Ni 29.84%, Fe 0.73%, Mn 0.75%, C 0.0089%, S<0.01%, P<0.01%, Pb <0.01%, Zn <0.01%, Si <0.01%, Sn <0.01%, and the balance is Cu. Performance: Tensile strength Rm is 378MPa, yield strength Rp0.2 is 135Mpa, elongation A11.3 is 40%, and grain size is 0.03mm; the mechanical properties yield strength and grain size of the prepared product do not meet the design performance requirements.

[0058] Comparative Example 5 A soft strip of high nickel white copper with a specification of 0.5×630mm and good surface and internal quality is produced.

[0059] The difference from Example 1 is that in step 6), the primary heating temperature is 1080°C and the holding time is 4.8 hours; the primary hot-rolled strip processing rate is 62.9%. In step 7), the secondary heating temperature is 980°C and the holding time is 4 hours; the primary hot-rolled strip processing rate is 82.1%. In step 8), the hot-rolled coil is milled, roughly rolled to 2.4mm, trimmed, and annealed in a bell furnace (annealing process: 620°C plus 5H for 6H). In step 10), annealing in a bell furnace is adopted, and the process is 620°C plus 5H for 6H. In step 12), annealing in a bell furnace is adopted, and the process is 620°C plus 5H for 6H.

[0060] After the first annealing, the strip was severely sintered, with many sticking defects on the surface. After the second annealing, it became very difficult to clean and unwind because of the sticking, and in some places, a layer of copper skin was peeled off after forcibly pulling it apart.

[0061] Samples are taken from the edges and the center of the finished strip in the width direction for testing.

[0062] Chemical composition: Ni content of the edge is 31.28%, C content is 0.011%; Ni content of the center is 31.25%, C content is 0.011%. The composition content is basically the same.

[0063] Performance: Edge: tensile strength Rm is 373MPa, yield strength Rp0.2 is 136Mpa, elongation A11.3 is 43.5%, grain size is 0.03mm; Center: tensile strength Rm is 420MPa, yield strength Rp0.2 is 198Mpa, elongation A11.3 is 38.5%, grain size is 0.02mm It can be seen that the mechanical properties of the finished product are very uneven.

[0064] Reason: The thinner the strip is, the easier it is for the layers to stick together after rolling. When a bell furnace is used for annealing, the heat is transferred from the outside to the inside or from the inside to the outside. High nickel white copper has poor thermal conductivity, and it takes a long time and high temperature to soften the strip completely. The layers are close together, the annealing temperature is high, and the time is long, which makes it very easy for the layers of the coil to stick together after annealing; when the width of the strip increases, the deadweight makes it easier for the edge to be stressed, and bonding is more likely to occur. Not only that, when the temperature and time are sufficient, the production efficiency decreases, and the grain size will grow in this case.

[0065] Table 1 Summary of the process and performance of Examples 1-5 and Comparative Examples 1-5 Based on the composition of BFe30~1~1 in the national standard, the copper strip was prepared by a traditional method. Compared with the strip prepared by the present invention, the results are shown in Table 2 below.

[0066] Table 2 Performance comparison between the material of the present invention and the product obtained by BFe30~1~1 in the national standard It can be seen from Table 2 that the wide high-nickel white copper thin soft strip prepared by the preparation method of the present invention has good performance.

[0067] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Any equivalent changes or modifications made according to the essence of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a wide high-nickel copper-nickel thin soft strip, characterized in that: The wide high-nickel white copper thin soft strip has a thickness of 0.3-1.0 mm and a width of ≥620 mm, and its composition by mass percentage includes: Ni 30.0-32.0%, Fe 0.6-1.0%, Mn 0.6-1.0%, C <0.03%, S <0.01%, P <0.01%, Pb <0.01%, Zn <0.01%, Si <0.01%, Sn <0.01%, the total amount of impurities ≤0.3, and the balance is Cu; The preparation method comprises the following steps: S1, weighing raw materials, adding the raw materials into the furnace for melting, and the copper liquid is exposed during the melting process; S2. After the copper in the furnace is fully liquefied, add calcined charcoal to cover it and adjust the content of the main component elements to the range of discharge from the furnace; S3. After the copper liquid has qualified components, the temperature is raised and copper and magnesium are added in a certain proportion for deoxidation; S4. After deoxidation is completed, a high-amplitude ingot casting system and a crystallizer are used for casting to obtain an ingot; S5, sawing the ingot obtained in S4 to obtain an ingot of required length; S6, heating the ingot once in a heating furnace, the heating temperature is 950-1080°C, the heating time is 3.0-5.0 hours, and the ingot is evenly heated and then taken out of the furnace; after the ingot is heated and taken out of the furnace, hot rolling is performed once; the processing rate of the hot rolling strip is 60-75%, the number of passes is 8, and the final rolling temperature is not less than 850°C; S7, after the hot-rolled strip is cooled, it is subjected to secondary heating at a temperature of 950-980°C for 3-4.5 hours; After the ingot is evenly heated, it is taken out of the furnace and hot rolled to the milling thickness, with a processing rate greater than 75%, and hot rolled to the milling thickness to obtain a hot rolled coil; S8, milling the hot-rolled coil, rough rolling the blank to 2.0-2.4 mm, trimming the edges, and annealing the hot-rolled coil in a bell furnace at a temperature of 620° C. for 6 hours; S9, performing a finish rolling on the strip coil obtained by the process in S8, and finishing rolling the strip coil to a thickness 1.5 to 2.0 times that of the finished product; S10, performing an air cushion furnace annealing heat treatment on the rolled strip, the annealing temperature is 720-800°C, the speed is 8-20m / min, a protective atmosphere is used during the annealing, the gas content is: 75% hydrogen, the rest is nitrogen; S11, performing secondary finish rolling on the annealed strip to the finished product thickness; S12, performing secondary air cushion furnace annealing heat treatment on the rolled strip, the annealing temperature is 720-800°C, the speed is 8-20m / min, and a protective atmosphere is used during annealing, the gas content is: 75% hydrogen, and the rest is nitrogen; S13. The qualified finished strips are cut, packaged and stored according to the required specifications.

2. The method for preparing a wide high-nickel copper-nickel thin soft strip according to claim 1, characterized in that: In step S1, the raw materials are old materials and / or new materials. When it is new material, Cu is added in the form of standard copper, Fe is added in the form of iron sheets, Mn is added in the form of electrolytic manganese, and Ni is added in the form of electrolytic nickel.

3. The method for preparing a wide high-nickel copper-nickel thin soft strip according to claim 1, characterized in that: In step S3, the amount of copper and magnesium added is 0.05-0.1% of the weight of the copper liquid.

4. The method for preparing a wide high-nickel copper-nickel thin soft strip according to claim 1, characterized in that: In step S4, a high-amplitude ingot casting system is arranged in a crystallizer, including a crucible and a casting tube with one end vertically extending into the crucible. Two through holes are arranged opposite to each other on the side wall of the crucible. The molten copper enters the crucible from the casting tube and then flows into the crystallizer through the through holes. In the crystallizer, the molten copper is cooled, solidified and crystallized by the cooling water in the crystallizer cavity, and is pulled downward by the ingot guide support to continuously perform casting.

5. The method for preparing a wide high-nickel copper-nickel thin soft strip according to claim 1, characterized in that: The material of the pouring tube is SiC or SiC composite material, and the material of the crucible is clay.

6. A wide high-nickel copper-nickel thin soft strip, characterized in that: The method is prepared by the method described in any one of claims 1 to 5.

7. A wide high-nickel copper-white thin soft strip according to claim 6, characterized in that: The wide high-nickel white copper thin soft strip has a tensile strength of 400-425 MPa, a yield strength of 170-200 MPa, an elongation of 38-42%, and a grain size of 0.01-0.02 mm.

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