White copper with good shielding performance and high yield strength and preparation method thereof

Abstract

The invention provides cupronickel with good shielding performance and high yield strength and a preparation method thereof, and belongs to the technical field of copper alloy manufacturing. By adding manganese and iron, the hardness and yield strength of the copper alloy can be remarkably improved, and the high-temperature softening resistance of the copper alloy is improved; the nickel and the copper can form an infinitely solid solution continuous solid solution, the alloy strength, the shielding performance and the corrosion resistance can be improved by adding the nickel element, meanwhile, the glossiness and the color of the alloy can be adjusted, and in addition, the nickel element can improve the shielding performance of the cupronickel; the tin element can refine grains, improve the tensile strength, yield strength and hardness of the cupronickel, prevent dezincification of the cupronickel and improve the corrosion resistance of the cupronickel; zinc has large solubility in a copper-nickel solid solution and has a strong solid solution strengthening effect, and the tensile strength, the yield strength and the hardness of the copper-nickel alloy are improved by adding the zinc element.

Description

Technical Field

[0001] The invention relates to the technical field of copper alloy manufacturing, and in particular to white copper with good shielding performance and high yield strength and a preparation method thereof. Background Art

[0002] White copper is a copper-based alloy with nickel as the main added element. It is silvery white and has a metallic luster, hence the name white copper. Copper and nickel can be infinitely dissolved in each other to form a continuous solid solution, that is, no matter how much the proportion of each other is, it is always an α-single-phase alloy. When nickel is melted into red copper and the content exceeds 16%, the color of the resulting alloy becomes as white as silver. The higher the nickel content, the whiter the color. The nickel content in white copper is generally 25%. The main function of white copper is to make mobile phone shielding covers, so it is not only required to have good mechanical properties, but also to have low electrical conductivity and magnetic permeability, so that it can have good shielding properties. With the development of the mobile phone industry, the weight of mobile phones is required to be lighter and lighter, so the thickness of the mobile phone shielding cover needs to be thinner. However, after the thickness of white copper becomes thinner, its tensile strength and yield strength will decrease, which will lead to problems in the stamping process, which will greatly increase the scrap rate of mobile phone shielding covers made of white copper, increase production costs, and limit its promotion and application in industry.

[0003] Therefore, how to improve the tensile strength and yield strength of white copper without affecting the shielding performance of white copper has become a technical problem to be solved urgently in this field. Summary of the invention

[0004] The object of the present invention is to provide a white copper with good shielding performance and high yield strength and a preparation method thereof. The white copper provided by the present invention not only has good shielding performance, but also has high tensile strength, hardness and elongation performance, and the yield strength is greatly improved.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The invention provides a white copper with good shielding performance and high yield strength, which comprises the following chemical components by mass percentage: Mn: 0.05-0.2%, Fe: 0.1-0.3%, Cu: 54-57%, Ni+Co: 15.5-19.5%, Sn≤0.1% and the balance Zn.

[0007] Preferably, in terms of mass percentage, the Fe content is greater than the Mn content.

[0008] The present invention provides a method for preparing the white copper with good shielding performance and high yield strength as described in the above technical solution, comprising the following steps:

[0009] (1) melting, horizontal continuous casting and initial rolling the alloy raw materials in sequence to obtain initial rolled strip;

[0010] (2) subjecting the initially rolled strip obtained in step (1) to first bell-type annealing and intermediate rolling in sequence to obtain an intermediate rolled strip;

[0011] (3) The intermediate rolled strip obtained in step (2) is subjected to a first continuous annealing, pre-finished product rolling, a second continuous annealing, finished product rolling, a third continuous annealing and a second bell-type annealing in sequence to obtain a nickel silver having good shielding properties and high yield strength.

[0012] Preferably, in the step (1), the temperature of the horizontal continuous casting is 1130-1180° C., and the pulling rate of the horizontal continuous casting is 120-180 mm / min.

[0013] Preferably, the total deformation amount of the initial rolling in step (1) is 50 to 95%.

[0014] Preferably, the temperature of the first bell-jar annealing in step (2) is 560-670° C., and the holding time of the first bell-jar annealing is 7-13 h.

[0015] Preferably, the total deformation amount of the intermediate rolling in step (2) is 60-80%.

[0016] Preferably, in step (3), the temperature of the first continuous annealing is 580-720° C., and the speed of the first continuous annealing is 25-45 m / min; the temperature of the second continuous annealing is 580-720° C., and the speed of the second continuous annealing is 25-45 m / min; the temperature of the third continuous annealing is 580-720° C., and the speed of the third continuous annealing is 35-75 m / min.

[0017] Preferably, the total deformation of the pre-product rolling and the finished product rolling in step (3) is independently 30-70%.

[0018] Preferably, the temperature of the second bell-jar annealing in step (3) is 350-540° C., and the holding time of the second bell-jar annealing is 5-12 hours.

[0019] The present invention provides a white copper with good shielding performance and high yield strength, which includes the following chemical components by mass percentage: Mn: 0.05-0.2%, Fe: 0.1-0.3%, Cu: 54-57%, Ni+Co: 15.5-19.5%, Sn≤0.1% and the balance Zn. The present invention can significantly improve the hardness and yield strength of the copper alloy and improve the high temperature softening resistance of the copper alloy by adding Mn and Fe elements; nickel and copper can form a continuous solid solution of infinite solid solution, and the alloy strength, shielding performance and corrosion resistance can be improved by adding nickel elements, and the gloss and color of the alloy can be adjusted at the same time. In addition, Ni elements can improve the shielding performance of white copper; Sn elements can refine grains, improve the tensile strength, yield strength and hardness of white copper, and can also prevent white copper from dezincification and improve the corrosion resistance of white copper; zinc elements have a large solubility in the copper-nickel solid solution and a strong solid solution strengthening effect, and adding zinc elements improves the tensile strength, yield strength and hardness of the copper-nickel alloy. The present invention optimizes the amount of each component in the cupronickel, and can significantly improve the tensile strength and yield strength of the cupronickel without affecting its shielding performance, so that the cupronickel can be stamped in a thinner state and still have good mechanical properties. The results of the examples show that the cupronickel provided by the present invention has good shielding performance and high yield strength, with a tensile strength of >605MPa, a yield strength of >425MPa, and an elongation of A 50 ≥24%, hardness>160HV, shielding performance>89.5dB. DETAILED DESCRIPTION

[0020] The invention provides a white copper with good shielding performance and high yield strength, which comprises the following chemical components by mass percentage: Mn: 0.05-0.2%, Fe: 0.1-0.3%, Cu: 54-57%, Ni+Co: 15.5-19.5%, Sn≤0.1% and the balance Zn.

[0021] The chemical composition of the cupronickel with good shielding performance and high yield strength provided by the present invention includes Mn: 0.05-0.2% by mass percentage. In the present invention, the Mn element can significantly improve the hardness and yield strength of the copper alloy, and improve the high temperature softening resistance of the copper alloy. As an embodiment of the present invention, the Mn content can be 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, 0.18% or 0.2%.

[0022] The chemical composition of the cupronickel with good shielding performance and high yield strength provided by the present invention includes Fe: 0.1-0.3% by mass percentage. In the present invention, the Fe element can significantly improve the hardness and yield strength of the copper alloy, and improve the high temperature softening resistance of the copper alloy. As an embodiment of the present invention, the Fe content can be 0.1%, 0.12%, 0.14%, 0.16%, 0.18%, 0.2%, 0.22%, 0.24%, 0.26%, 0.28% or 0.3%.

[0023] In the present invention, the content of Fe is preferably greater than the content of Mn by mass percentage. In the present invention, the Fe element and the Mn element can play a good synergistic role, and the obtained cupronickel has higher mechanical properties than a single component, and when the content of the Fe element is greater than the content of the Mn, the tensile strength and yield strength of the cupronickel are higher when the total amount of the Fe element and the Mn element is the same.

[0024] The chemical composition of the cupronickel with good shielding performance and high yield strength provided by the present invention includes Cu: 54-57% by mass percentage. In the present invention, the Cu element is the matrix element of the cupronickel. As an embodiment of the present invention, the content of Cu can be 54%, 54.5%, 55%, 55.5%, 56%, 56.5% or 57%.

[0025] In terms of mass percentage, the chemical composition of the white copper with good shielding performance and high yield strength provided by the present invention includes Ni+Co: 15.5-19.5%. In the present invention, nickel and copper can form a continuous solid solution with infinite solid solution. By adding nickel element, the strength, shielding performance and corrosion resistance of the alloy can be improved, and the gloss and color of the alloy can be adjusted. In addition, the Ni element can improve the shielding performance of the white copper. In the present invention, the Co element is an inevitable impurity of Ni in the smelting process, and the content is very small and can be ignored. As an embodiment of the present invention, the content of Ni+Co can be 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19% or 19.5%.

[0026] The chemical composition of the cupronickel with good shielding performance and high yield strength provided by the present invention includes Sn≤0.1% by mass percentage. In the present invention, the Sn element can refine the grains, improve the tensile strength, yield strength and hardness of the cupronickel, and also prevent the cupronickel from dezincification and improve the corrosion resistance of the cupronickel. As an embodiment of the present invention, the content of Sn can be 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09% or 0.1%.

[0027] The chemical composition of the white copper with good shielding performance and high yield strength provided by the present invention includes a balance of Zn by mass percentage. In the present invention, the zinc element has a large solubility in the copper-nickel solid solution and has a strong solid solution strengthening effect. The addition of the zinc element improves the tensile strength, yield strength and hardness of the copper-nickel alloy.

[0028] The present invention can significantly improve the hardness and yield strength of the copper alloy and improve the high temperature softening performance of the copper alloy by adding Mn and Fe elements; nickel and copper can form a continuous solid solution of infinite solid solution, and the alloy strength, shielding performance and corrosion resistance can be improved by adding nickel elements, and the glossiness and color of the alloy can be adjusted at the same time. In addition, the Ni element can improve the shielding performance of white copper; the Sn element can refine the grains, improve the tensile strength, yield strength and hardness of white copper, and can also prevent white copper from dezincification and improve the corrosion resistance of white copper; the zinc element has a large solubility in the copper-nickel solid solution and has a strong solid solution strengthening effect. The addition of zinc elements improves the tensile strength, yield strength and hardness of the copper-nickel alloy. The present invention can significantly improve the tensile strength and yield strength of white copper without affecting its shielding performance by optimizing the amount of each component in white copper, so that white copper can be stamped in a thinner state and has good mechanical properties.

[0029] The present invention also provides a method for preparing the white copper with good shielding performance and high yield strength as described in the above technical solution, comprising the following steps:

[0030] (1) melting, horizontal continuous casting and initial rolling the alloy raw materials in sequence to obtain initial rolled strip;

[0031] (2) subjecting the initially rolled strip obtained in step (1) to first bell-type annealing and intermediate rolling in sequence to obtain an intermediate rolled strip;

[0032] (3) The intermediate rolled strip obtained in step (2) is subjected to a first continuous annealing, pre-finished product rolling, a second continuous annealing, finished product rolling, a third continuous annealing and a second bell-type annealing in sequence to obtain a nickel silver having good shielding properties and high yield strength.

[0033] The invention sequentially performs smelting, horizontal continuous casting and initial rolling on alloy raw materials to obtain initial rolled strips.

[0034] In the present invention, the alloy raw materials preferably include pure nickel, electrolytic copper, copper-manganese master alloy, copper-tin master alloy, copper-iron master alloy, pure zinc and recycled waste. In the present invention, the recycled waste preferably includes milling waste and rolling waste generated when preparing high-performance nickel silver. The present invention has no special restrictions on the specific composition of the copper-manganese master alloy, copper-tin master alloy and copper-iron master alloy, which can be determined according to the technical common sense of those skilled in the art. The present invention has no special restrictions on the specific amount of the alloy raw materials, as long as the chemical composition of the product meets the requirements. The present invention uses recycled waste as the alloy raw material. Since the recycled waste is the milling waste and rolling waste generated when preparing high-performance nickel silver, its composition is controllable, which can not only ensure that the chemical composition of the high-performance nickel silver meets the requirements, but also can achieve the reuse of waste, saving a lot of production costs.

[0035] The present invention has no special limitation on the process parameters of the smelting, which can be determined according to the technical common sense of those skilled in the art, as long as the raw materials can be completely melted and mixed evenly.

[0036] In the present invention, the temperature of the horizontal continuous casting is preferably 1130-1180°C; the pulling rate of the horizontal continuous casting is preferably 120-180 mm / min. As an embodiment of the present invention, the temperature of the semi-continuous casting can be 1130°C, 1140°C, 1150°C, 1160°C, 1170°C or 1180°C; the pulling rate of the semi-continuous casting can be 120 mm / min, 130 mm / min, 140 mm / min, 150 mm / min, 160 mm / min, 170 mm / min or 180 mm / min.

[0037] The present invention preferably further comprises milling the horizontal continuous casting product. The present invention has no particular limitation on the specific operation of the milling and the thickness of the milling, as long as the oxide layer on the surface of the product can be removed. As an embodiment of the present invention, the thickness of the milling can be 0.8 mm, 0.9 mm, 1 mm, 1.1 mm or 1.2 mm.

[0038] In the present invention, the total deformation of the initial rolling is preferably 50-95%; the initial rolling is preferably cold rolling. The present invention has no special limitation on the deformation of a single pass and the number of passes during the cold rolling, which can be determined according to the technical common sense of the technicians in the field. The present invention can greatly reduce the thickness of the nickel silver blank through initial rolling, which can eliminate casting defects, break coarse grains, and improve its performance on the one hand, and is conducive to the subsequent preparation of nickel silver with thickness meeting the requirements on the other hand. As an embodiment of the present invention, the total deformation of the initial rolling can be 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95%; the deformation of a single pass of the initial rolling can be 9-30%, and can also be 9%, 10%, 15%, 20%, 25% or 30%; the number of passes of the initial rolling can be 10-15, and can also be 10, 11, 12, 13, 14 or 15.

[0039] In the present invention, the thickness of the as-rolled strip is preferably 1 to 3.6 mm. The present invention controls the thickness of the as-rolled strip, which is beneficial to subsequent mechanical processing to obtain white copper of the desired thickness. As an embodiment of the present invention, the thickness of the as-rolled strip can be 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm or 3.6 mm.

[0040] After obtaining the initial rolled strip, the present invention sequentially performs the first bell-shaped annealing and intermediate rolling on the plate and strip to obtain the intermediate rolled strip.

[0041] The present invention preferably performs preliminary trimming on the plate and strip material first, and then performs the first bell-jar annealing. The present invention has no special limitation on the specific operation of the preliminary trimming, and the trimming operation well known to those skilled in the art can be used to trim the unevenly deformed parts on both sides of the plate and strip material. The present invention can remove the unevenly deformed parts through trimming, and at the same time remove the oxygen-enriched parts on both sides of the plate and strip material after the blanking and initial rolling, thereby reducing the influence of oxygen elements on the plate and strip material.

[0042] In the present invention, the temperature of the first bell-jar annealing is preferably 560-670°C; the holding time of the first bell-jar annealing is preferably 7-13h. The present invention has no special limitation on the atmosphere of the first bell-jar annealing. It can be determined according to the technical common sense of those skilled in the art to avoid oxidation during the annealing process. The present invention can remove the stress generated during the initial rolling process through the first bell-jar annealing on the one hand, and on the other hand, it can transform the processing structure of the material into a recrystallized structure, while improving the plasticity of the alloy for subsequent rolling. As an embodiment of the present invention, the temperature of the first bell-jar annealing can be 560°C, 580°C, 600°C, 620°C, 640°C, 650°C or 670°C; the holding time of the first bell-jar annealing can be 7h, 8h, 9h, 10h, 11h, 12h or 13h.

[0043] The present invention preferably performs brushing on the product of the first bell-jar annealing and then performs intermediate rolling. The present invention has no special limitation on the specific operation of the brushing, and it only needs to remove impurities on the surface of the product.

[0044] In the present invention, the total deformation of the intermediate rolling is preferably 60-80%; the intermediate rolling is preferably cold rolling. The present invention has no special limitation on the deformation of a single pass and the number of processing passes of the intermediate rolling, which can be determined according to the technical common sense of those skilled in the art. The present invention can further reduce the size of the initial strip through intermediate rolling on the one hand, and crush the coarse grains produced after annealing on the other hand. As an embodiment of the present invention, the total deformation of the intermediate rolling can be 60%, 65%, 70%, 75% or 80%; the deformation of a single pass of the intermediate rolling can be 9-36%, and can also be 9%, 10%, 15%, 20%, 25%, 30% or 36%; the number of passes of the intermediate rolling can be 8-13, and can also be 8, 9, 10, 11, 12 or 13.

[0045] In the present invention, the thickness of the intermediate rolled strip is preferably 0.3 to 1.44 mm.

[0046] After obtaining the intermediate rolled strip, the present invention sequentially performs the first continuous annealing, pre-finished product rolling, the second continuous annealing, finished product rolling, the third continuous annealing and the second bell-type annealing on the intermediate rolled strip to obtain white copper with good shielding performance and high yield strength.

[0047] In the present invention, the temperature of the first continuous annealing is preferably 580-720°C; the speed of the first continuous annealing is preferably 25-45m / min. In the present invention, the grain size of the product of the first continuous annealing is preferably 0.005-0.02mm. The present invention has no special limitation on the atmosphere of the first continuous annealing, and it is sufficient to avoid oxidation of the white copper during the annealing process. The present invention can improve the plasticity of the rolled white copper sheet and strip through the first continuous annealing, which is convenient for subsequent rolling, and can make the grain size uniform on the other hand. As an embodiment of the present invention, the temperature of the first continuous annealing can be 580°C, 600°C, 620°C, 640°C, 660°C, 680°C, 700°C or 720°C; the speed of the first continuous annealing can be 25m / min, 30m / min, 35m / min, 40m / min or 45m / min.

[0048] In the present invention, the total deformation of the pre-finished product rolling is preferably 30-70%; the pre-finished product rolling is preferably cold rolling. The present invention has no special limitation on the deformation of the single pass and the number of processing passes of the pre-finished product rolling, which can be determined according to the technical common sense of those skilled in the art. The present invention can further reduce the size of the nickel silver sheet and strip through the rolling of the pre-finished product, and at the same time improve the uniformity of the structure of the nickel silver and further improve its mechanical properties. As an embodiment of the present invention, the total deformation of the pre-finished product rolling can be 30%, 40%, 50%, 60% or 70%; the deformation of the single pass of the pre-finished product rolling can be 9-36%, and can also be 9%, 10%, 15%, 20%, 25%, 30% or 36%; the number of passes of the pre-finished product rolling can be 6-11, and can also be 6, 7, 8, 9, 10 or 11.

[0049] In the present invention, the thickness of the product obtained by rolling the pre-finished product is preferably 0.15 to 0.7 mm.

[0050] In the present invention, the temperature of the second continuous annealing is preferably 580-720°C; the speed of the second continuous annealing is preferably 25-45m / min. In the present invention, the grain size of the product of the second continuous annealing is preferably 0.005-0.02mm. The present invention has no special limitation on the atmosphere of the second continuous annealing, and can avoid oxidation of white copper during the annealing process. The present invention can improve the plasticity of the rolled white copper sheet and strip through the second continuous annealing, which is convenient for subsequent rolling, and can make the grain size more uniform on the other hand. As an embodiment of the present invention, the temperature of the second continuous annealing can be 580°C, 600°C, 620°C, 640°C, 660°C, 680°C, 700°C or 720°C; the speed of the second continuous annealing can be 25m / min, 30m / min, 35m / min, 40m / min or 45m / min.

[0051] In the present invention, the total deformation of the finished product rolling is preferably 30-70%; the finished product rolling is preferably cold rolling. The present invention has no special limitation on the deformation of the single pass and the processing pass of the finished product rolling, which can be determined according to the technical common sense of those skilled in the art. The present invention can further reduce the size of the nickel silver sheet and strip through the finished product rolling, and at the same time improve the uniformity of the structure of the nickel silver and further improve its mechanical properties. As an embodiment of the present invention, the total deformation of the finished product rolling can be 30%, 40%, 50%, 60% or 70%; the deformation of the single pass of the finished product rolling can be 9-36%, and can also be 9%, 10%, 15%, 20%, 25%, 30% or 36%; the number of passes of the finished product rolling can be 6-11, and can also be 6, 7, 8, 9, 10 or 11.

[0052] In the present invention, the thickness of the product obtained by rolling the finished product is preferably 0.08 to 0.4 mm.

[0053] In the present invention, the temperature of the third continuous annealing is preferably 580-720°C; the speed of the third continuous annealing is preferably 35-75m / min. In the present invention, the grain size of the product of the third continuous annealing is preferably 0.005-0.02mm. The present invention has no special limitation on the atmosphere of the third continuous annealing, and it is sufficient to avoid oxidation of white copper during the annealing process. The present invention makes the grain size uniform through the third continuous annealing. As an embodiment of the present invention, the temperature of the third continuous annealing can be 580°C, 600°C, 620°C, 640°C, 660°C, 680°C, 700°C or 720°C; the speed of the third continuous annealing can be 35m / min, 40m / min, 45m / min, 50m / min, 55m / min, 60m / min, 65m / min, 70m / min or 75m / min.

[0054] The present invention preferably further comprises pickling the product of the third continuous annealing. The present invention has no particular limitation on the specific operation of pickling and the composition of the pickling solution used, and conventional white copper pickling well known to those skilled in the art can be used to remove the oxide layer on the surface of the product and passivate it.

[0055] In the present invention, the temperature of the second bell-jar annealing is preferably 350-540°C; the holding time of the second bell-jar annealing is preferably 5-12h. The present invention has no special limitation on the atmosphere of the second bell-jar annealing, as long as it can prevent the nickel silver from being oxidized during the annealing process. The present invention can remove the residual stress in the alloy by performing the bell-jar annealing at the end, and on the other hand, it can play a role in homogenization treatment, making the internal structure of the alloy more uniform, thereby further improving the strength and ductility of the nickel silver.

[0056] The present invention can significantly reduce the thickness of the nickel silver blank through the initial rolling, eliminate casting defects, break up the coarse crystal grains and improve the performance; through the first bell-shaped annealing, on the one hand, the stress generated in the initial rolling process can be removed, and on the other hand, the processing structure of the material can be transformed into a recrystallized structure, and the plasticity of the alloy can be improved, so as to facilitate subsequent rolling; the intermediate rolling performed thereafter can, on the one hand, further reduce the size of the initial rolled strip, and on the other hand, break up the coarse crystal grains generated after annealing; finally, through three continuous annealings and two rollings, the nickel silver can make its crystal grain size uniform even after a large deformation, and can always be kept in a very small range, thereby improving the uniformity of the structure, and further making the nickel silver still have high tensile strength, yield strength and hardness when the size is very small; through the final bell-shaped annealing, on the one hand, the residual stress in the alloy can be removed, and on the other hand, the structure inside the alloy can be more uniform, thereby further improving the strength and ductility of the nickel silver.

[0057] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] Example 1

[0059] A white copper with good shielding performance and high yield strength, the chemical composition of which is, by mass percentage, 0.12% Mn, 0.13% Fe, 54.4% Cu, 16.9% Ni+Co, 0.05% Sn and the balance Zn;

[0060] The preparation method of the white copper with good shielding performance and high yield strength is as follows:

[0061] (1) pure nickel, electrolytic copper, copper-manganese master alloy, copper-tin master alloy, copper-iron master alloy, pure zinc and recycled waste are sequentially smelted, horizontally continuously cast, milled and initially rolled to obtain an initially rolled strip; the temperature of the horizontal continuous casting is 1150° C., the pulling rate of the horizontal continuous casting is 130 mm / min; the total deformation of the initial rolling is 75%, the number of initial rolling passes is 10, and the initial rolling is cold rolling;

[0062] (2) the plate and strip material obtained in step (1) is subjected to initial trimming, first bell-shaped annealing, brushing and intermediate rolling in sequence to obtain an intermediate rolled strip material; the temperature of the first bell-shaped annealing is 620° C., and the holding time of the first bell-shaped annealing is 8 h; the total deformation of the intermediate rolling is 65%, the number of intermediate rolling passes is 8, and the intermediate rolling is cold rolling;

[0063] (3) subjecting the intermediate rolled strip obtained in step (2) to sequentially first continuous annealing, pre-finished product rolling, second continuous annealing, finished product rolling, third continuous annealing, pickling and second bell-type annealing to obtain white copper with good shielding performance and high yield strength; the temperature of the first continuous annealing is 680° C., the speed of the first continuous annealing is 35 m / min, and the grain size of the product of the first continuous annealing is 0.02 mm; the total deformation of the pre-finished product rolling is 50%, the number of passes of the pre-finished product rolling is 6, and the pre-finished product rolling is cold rolling; the first continuous annealing is performed at a temperature of 680° C., a speed of 35 m / min, and a grain size of the product of the first continuous annealing is 0.02 mm; the total deformation of the pre-finished product rolling is 50%, the number of passes of the pre-finished product rolling is 6, and the pre-finished product rolling is cold rolling; The temperature of the second continuous annealing is 680°C, the speed of the second continuous annealing is 35m / min, and the grain size of the product of the second continuous annealing is 0.015mm; the total deformation of the finished product rolling is 40%, the number of passes of the finished product rolling is 6, and the finished product rolling is cold rolling; the temperature of the third continuous annealing is 620°C, the speed of the third continuous annealing is 72m / min, and the grain size of the product of the third continuous annealing is 0.01mm; the temperature of the second bell-shaped annealing is 350°C; and the holding time of the second bell-shaped annealing is 8h.

[0064] Example 2

[0065] A white copper with good shielding performance and high yield strength, the chemical composition of which is, by mass percentage, 0.15% Mn, 0.16% Fe, 54.6% Cu, 18.5% Ni+Co, 0.03% Sn and the balance Zn;

[0066] The preparation method of the white copper with good shielding performance and high yield strength is as follows:

[0067] (1) pure nickel, electrolytic copper, copper-manganese master alloy, copper-tin master alloy, copper-iron master alloy, pure zinc and recycled waste are sequentially smelted, horizontally continuously cast, milled and initially rolled to obtain an initially rolled strip; the temperature of the horizontal continuous casting is 1165° C., the pulling rate of the horizontal continuous casting is 160 mm / min; the total deformation of the initial rolling is 85%, the number of initial rolling passes is 10, and the initial rolling is cold rolling;

[0068] (2) the plate and strip material obtained in step (1) is subjected to initial trimming, first bell-shaped annealing, brushing and intermediate rolling in sequence to obtain an intermediate rolled strip material; the temperature of the first bell-shaped annealing is 620° C., and the holding time of the first bell-shaped annealing is 8 h; the total deformation of the intermediate rolling is 70%, the number of intermediate rolling passes is 8, and the intermediate rolling is cold rolling;

[0069] (3) subjecting the intermediate rolled strip obtained in step (2) to sequentially perform a first continuous annealing, pre-finished product rolling, a second continuous annealing, finished product rolling, a third continuous annealing, pickling and a second bell-type annealing to obtain a white copper with good shielding performance and high yield strength; the temperature of the first continuous annealing is 620° C., the speed of the first continuous annealing is 35 m / min, and the grain size of the product of the first continuous annealing is 0.02 mm; the total deformation of the pre-finished product rolling is 48%, the number of passes of the pre-finished product rolling is 6, and the pre-finished product rolling is cold rolling; the The temperature of the second continuous annealing is 660°C, the speed of the second continuous annealing is 40m / min, and the grain size of the product of the second continuous annealing is 0.015mm; the total deformation of the finished product rolling is 56%, the number of passes of the finished product rolling is 6, and the finished product rolling is cold rolling; the temperature of the third continuous annealing is 680°C, the speed of the third continuous annealing is 45m / min, and the grain size of the product of the third continuous annealing is 0.02mm; the temperature of the second bell-shaped annealing is 500°C; and the holding time of the second bell-shaped annealing is 6h.

[0070] Comparative Example 1

[0071] A white copper, the chemical composition of which is, by mass percentage, 0.135% of Mn, 0.135% of Fe, 54.4% of Cu, 18.8% of Ni+Co, 0.06% of Sn and the balance of Zn;

[0072] The preparation method of the white copper is:

[0073] (1) pure nickel, electrolytic copper, copper-manganese master alloy, copper-tin master alloy, copper-iron master alloy, pure zinc and recycled waste are sequentially smelted, horizontally continuously cast, milled and initially rolled to obtain an initially rolled strip; the temperature of the horizontal continuous casting is 1145° C., the pulling rate of the horizontal continuous casting is 140 mm / min; the total deformation of the initial rolling is 88%, the number of initial rolling passes is 10, and the initial rolling is cold rolling;

[0074] (2) the plate and strip material obtained in step (1) is subjected to initial trimming, first bell-shaped annealing, brushing and intermediate rolling in sequence to obtain an intermediate rolled strip material; the temperature of the first bell-shaped annealing is 630° C., and the holding time of the first bell-shaped annealing is 9 hours; the total deformation of the intermediate rolling is 68%, the number of intermediate rolling passes is 8, and the intermediate rolling is cold rolling;

[0075] (3) The intermediate rolled strip obtained in the step (2) is subjected to a first continuous annealing, finished product rolling, a second continuous annealing, pickling and a second bell-jar annealing in sequence to obtain white copper; the temperature of the first continuous annealing is 620° C., the speed of the first continuous annealing is 38 m / min, and the grain size of the product of the first continuous annealing is 0.01 mm; the total deformation of the finished product rolling is 40%, the number of passes of the finished product rolling is 6 passes, and the finished product rolling is cold rolling; the temperature of the second continuous annealing is 680° C., the speed of the second continuous annealing is 44 m / min, and the grain size of the product of the second continuous annealing is 0.005 mm; the temperature of the second bell-jar annealing is 390° C.; and the holding time of the second bell-jar annealing is 6 h.

[0076] Comparative Example 2

[0077] A white copper, the chemical composition of which is, by mass percentage, 0.135% of Mn, 0.135% of Fe, 63.4% of Cu, 18.8% of Ni+Co and the balance of Zn;

[0078] The preparation method of the white copper is:

[0079] (1) pure nickel, electrolytic copper, copper-manganese master alloy, copper-iron master alloy, pure zinc and recycled waste are sequentially smelted, horizontally continuously cast, milled and initially rolled to obtain an initially rolled strip; the temperature of the horizontal continuous casting is 1150° C., the pulling rate of the horizontal continuous casting is 170 mm / min; the total deformation of the initial rolling is 78%, the number of initial rolling passes is 10, and the initial rolling is cold rolling;

[0080] (2) the plate and strip material obtained in step (1) is subjected to initial trimming, first bell-jar annealing, brushing and intermediate rolling in sequence to obtain an intermediate rolled strip material; the temperature of the first bell-jar annealing is 630° C., and the holding time of the first bell-jar annealing is 9 hours; the total deformation of the intermediate rolling is 80%, the number of intermediate rolling passes is 8, and the intermediate rolling is cold rolling;

[0081] (3) The intermediate rolled strip obtained in the step (2) is subjected to a first continuous annealing, finished product rolling, a second continuous annealing, pickling and a second bell-jar annealing in sequence to obtain white copper; the temperature of the first continuous annealing is 680° C., the speed of the first continuous annealing is 40 m / min, and the grain size of the product of the first continuous annealing is 0.015 mm; the total deformation of the finished product rolling is 45%, the number of passes of the finished product rolling is 6 passes, and the finished product rolling is cold rolling; the temperature of the second continuous annealing is 680° C., the speed of the second continuous annealing is 44 m / min, and the grain size of the product of the second continuous annealing is 0.02 mm; the temperature of the second bell-jar annealing is 410° C.; and the holding time of the second bell-jar annealing is 6 hours.

[0082] Comparative Example 3

[0083] A white copper, the chemical composition of which is, by mass percentage, 0.25% Mn, 54.4% Cu, 16.9% Ni+Co, 0.05% Sn and the balance Zn;

[0084] The preparation method of the white copper is:

[0085] (1) pure nickel, electrolytic copper, copper-manganese master alloy, copper-tin master alloy, pure zinc and recycled waste are sequentially smelted, horizontally continuously cast, milled and initially rolled to obtain an initially rolled strip; the temperature of the horizontal continuous casting is 1150° C., the pulling rate of the horizontal continuous casting is 130 mm / min; the total deformation of the initial rolling is 75%, the number of initial rolling passes is 10, and the initial rolling is cold rolling;

[0086] (2) the plate and strip material obtained in step (1) is subjected to initial trimming, first bell-shaped annealing, brushing and intermediate rolling in sequence to obtain an intermediate rolled strip material; the temperature of the first bell-shaped annealing is 620° C., and the holding time of the first bell-shaped annealing is 8 h; the total deformation of the intermediate rolling is 65%, the number of intermediate rolling passes is 8, and the intermediate rolling is cold rolling;

[0087] (3) subjecting the intermediate rolled strip obtained in step (2) to first continuous annealing, pre-finished product rolling, second continuous annealing, finished product rolling, third continuous annealing, pickling and second bell-type annealing in sequence to obtain white copper; the temperature of the first continuous annealing is 680° C., the speed of the first continuous annealing is 35 m / min, and the grain size of the product of the first continuous annealing is 0.02 mm; the total deformation of the pre-finished product rolling is 50%, the number of passes of the pre-finished product rolling is 6, and the pre-finished product rolling is cold rolling; the second continuous annealing is The temperature is 680°C, the speed of the second continuous annealing is 35m / min, and the grain size of the product of the second continuous annealing is 0.015mm; the total deformation of the finished product rolling is 40%, the number of passes of the finished product rolling is 6, and the finished product rolling is cold rolling; the temperature of the third continuous annealing is 620°C, the speed of the third continuous annealing is 72m / min, and the grain size of the product of the third continuous annealing is 0.01mm; the temperature of the second bell-shaped annealing is 350°C; and the holding time of the second bell-shaped annealing is 8h.

[0088] Comparative Example 4

[0089] A white copper, the chemical composition of which is, by mass percentage, 0.25% Fe, 54.4% Cu, 16.9% Ni+Co, 0.05% Sn and the balance Zn;

[0090] The preparation method of the white copper is:

[0091] (1) pure nickel, electrolytic copper, copper-tin master alloy, copper-iron master alloy, pure zinc and recycled waste are sequentially smelted, horizontally continuously cast, milled and initially rolled to obtain an initially rolled strip; the temperature of the horizontal continuous casting is 1150° C., the pulling rate of the horizontal continuous casting is 130 mm / min; the total deformation of the initial rolling is 75%, the number of initial rolling passes is 10, and the initial rolling is cold rolling;

[0092] (2) the plate and strip material obtained in step (1) is subjected to initial trimming, first bell-shaped annealing, brushing and intermediate rolling in sequence to obtain an intermediate rolled strip material; the temperature of the first bell-shaped annealing is 620° C., and the holding time of the first bell-shaped annealing is 8 h; the total deformation of the intermediate rolling is 65%, the number of intermediate rolling passes is 8, and the intermediate rolling is cold rolling;

[0093] (3) subjecting the intermediate rolled strip obtained in step (2) to first continuous annealing, pre-finished product rolling, second continuous annealing, finished product rolling, third continuous annealing, pickling and second bell-type annealing in sequence to obtain white copper; the temperature of the first continuous annealing is 680° C., the speed of the first continuous annealing is 35 m / min, and the grain size of the product of the first continuous annealing is 0.02 mm; the total deformation of the pre-finished product rolling is 50%, the number of passes of the pre-finished product rolling is 6, and the pre-finished product rolling is cold rolling; the second continuous annealing is The temperature is 680°C, the speed of the second continuous annealing is 35m / min, and the grain size of the product of the second continuous annealing is 0.015mm; the total deformation of the finished product rolling is 40%, the number of passes of the finished product rolling is 6, and the finished product rolling is cold rolling; the temperature of the third continuous annealing is 620°C, the speed of the third continuous annealing is 72m / min, and the grain size of the product of the third continuous annealing is 0.01mm; the temperature of the second bell-shaped annealing is 350°C; and the holding time of the second bell-shaped annealing is 8h.

[0094] Comparative Example 5

[0095] A white copper with good shielding performance and high yield strength, the chemical composition of which is, by mass percentage, 0.18% Mn, 0.07% Fe, 54.4% Cu, 16.9% Ni+Co, 0.05% Sn and the balance Zn;

[0096] The preparation method of the white copper with good shielding performance and high yield strength is as follows:

[0097] (1) pure nickel, electrolytic copper, copper-manganese master alloy, copper-tin master alloy, copper-iron master alloy, pure zinc and recycled waste are sequentially smelted, horizontally continuously cast, milled and initially rolled to obtain an initially rolled strip; the temperature of the horizontal continuous casting is 1150° C., the pulling rate of the horizontal continuous casting is 130 mm / min; the total deformation of the initial rolling is 75%, the number of initial rolling passes is 10, and the initial rolling is cold rolling;

[0098] (2) the plate and strip material obtained in step (1) is subjected to initial trimming, first bell-shaped annealing, brushing and intermediate rolling in sequence to obtain an intermediate rolled strip material; the temperature of the first bell-shaped annealing is 620° C., and the holding time of the first bell-shaped annealing is 8 h; the total deformation of the intermediate rolling is 65%, the number of intermediate rolling passes is 8, and the intermediate rolling is cold rolling;

[0099] (3) subjecting the intermediate rolled strip obtained in step (2) to sequentially first continuous annealing, pre-finished product rolling, second continuous annealing, finished product rolling, third continuous annealing, pickling and second bell-type annealing to obtain white copper with good shielding performance and high yield strength; the temperature of the first continuous annealing is 680° C., the speed of the first continuous annealing is 35 m / min, and the grain size of the product of the first continuous annealing is 0.02 mm; the total deformation of the pre-finished product rolling is 50%, the number of passes of the pre-finished product rolling is 6, and the pre-finished product rolling is cold rolling; the first continuous annealing is performed at a temperature of 680° C., a speed of 35 m / min, and a grain size of the product of the first continuous annealing is 0.02 mm; the total deformation of the pre-finished product rolling is 50%, the number of passes of the pre-finished product rolling is 6, and the pre-finished product rolling is cold rolling; The temperature of the second continuous annealing is 680°C, the speed of the second continuous annealing is 35m / min, and the grain size of the product of the second continuous annealing is 0.015mm; the total deformation of the finished product rolling is 40%, the number of passes of the finished product rolling is 6, and the finished product rolling is cold rolling; the temperature of the third continuous annealing is 620°C, the speed of the third continuous annealing is 72m / min, and the grain size of the product of the third continuous annealing is 0.01mm; the temperature of the second bell-shaped annealing is 350°C; and the holding time of the second bell-shaped annealing is 8h.

[0100] The properties of the white copper prepared in Examples 1 to 2 and Comparative Examples 1 to 5 were tested, and the results are shown in Table 1:

[0101] Table 1 Properties of white copper prepared in Examples 1 to 2 and Comparative Examples 1 to 5

[0102]

[0103]

[0104] Among them, the test method for tensile strength is: GB / T 34505-2017 room temperature tensile test method;

[0105] The test method for yield strength is: GB / T 34505-2017 room temperature tensile test method;

[0106] The test method for elongation is: GB / T 22834505-2017 Room temperature tensile test method;

[0107] The test method for shielding performance is: GB / T30142-2013 Test method for shielding effectiveness of planar electromagnetic shielding materials.

[0108] In Table 1, it can be seen from the comparison between Examples 1 to 2 and Comparative Examples 1 to 2 that when the chemical composition of white copper is similar, the present invention can improve the tensile strength, yield strength and hardness of white copper without affecting its shielding performance by adding one more continuous annealing and cold rolling process, among which the improvement of yield strength is relatively large; it can be seen from the comparison between Examples 1 to 2 and Comparative Examples 3 to 5 that when the preparation process of white copper is similar, by adding Mn element and Fe element to white copper and controlling the dosage relationship of the two to be Fe content>Mn content, the yield strength of white copper is greatly improved compared with adding a single Mn element or Fe element, or Mn content>Fe content. It can be seen from the above comparison that by adopting the chemical composition and preparation process provided by the present invention, the mechanical properties of white copper, especially its yield strength, can be comprehensively improved.

[0109] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A white copper with good shielding performance and high yield strength, comprising the following chemical components by mass percentage: Mn: 0.05-0.2%, Fe: 0.1-0.3%, Cu: 54-57%, Ni+Co: 15.5-19.5%, Sn≤0.1% and the balance Zn.

2. The white copper with good shielding performance and high yield strength according to claim 1, characterized in that: In terms of mass percentage, the Fe content is greater than the Mn content.

3. The method for preparing the white copper with good shielding performance and high yield strength according to claim 1 or 2 comprises the following steps: (1) melting, horizontal continuous casting and initial rolling the alloy raw materials in sequence to obtain initial rolled strip; (2) subjecting the initially rolled material obtained in step (1) to first bell-type annealing and intermediate rolling in sequence to obtain an intermediate rolled strip; (3) The intermediate rolled strip obtained in step (2) is subjected to a first continuous annealing, pre-finished product rolling, a second continuous annealing, finished product rolling, a third continuous annealing and a second bell-type annealing in sequence to obtain a nickel silver having good shielding properties and high yield strength.

4. The preparation method according to claim 3, characterized in that: In the step (1), the temperature of the horizontal continuous casting is 1130-1180° C., and the pulling rate of the horizontal continuous casting is 120-180 mm / min.

5. The preparation method according to claim 3, characterized in that: The total deformation amount of the initial rolling in the step (1) is 50 to 95%.

6. The preparation method according to claim 3, characterized in that: The temperature of the first bell-jar annealing in step (2) is 560-670° C., and the holding time of the first bell-jar annealing is 7-13 hours.

7. The preparation method according to claim 3, characterized in that: The total deformation amount of the intermediate rolling in the step (2) is 60 to 80%.

8. The preparation method according to claim 3, characterized in that: In the step (3), the temperature of the first continuous annealing is 580-720° C., and the speed of the first continuous annealing is 25-45 m / min; the temperature of the second continuous annealing is 580-720° C., and the speed of the second continuous annealing is 25-45 m / min; the temperature of the third continuous annealing is 580-720° C., and the speed of the third continuous annealing is 35-75 m / min.

9. The preparation method according to claim 3, characterized in that: The total deformation of the pre-product rolling and the finished product rolling in the step (3) is independently 30 to 70%.

10. The preparation method according to claim 3, characterized in that: The temperature of the second bell-jar annealing in step (3) is 350-540° C., and the holding time of the second bell-jar annealing is 5-12 hours.

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