Ultrafine-grain high-yield bronze and preparation method thereof

Abstract

The invention provides ultra-fine grain high-yield bronze and a preparation method thereof, and belongs to the technical field of copper alloy manufacturing. The added tin can form a continuous solid solution with copper, has a wide single-phase region, and can obviously improve the mechanical property and corrosion resistance of copper; by adding phosphorus, the flowability of a melt can be improved, the problem of element segregation of a cast ingot can be remarkably reduced, phosphorus serves as an effective deoxidizing agent of the copper alloy, the adverse effect of oxygen in the copper alloy is reduced, and therefore the strength and hardness of the copper alloy are effectively improved, in addition, phosphorus can reduce product air suction in horizontal continuous casting, and the physical performance of bronze can be improved; iron can remarkably improve the strength and hardness of the copper alloy; nickel can generate an amplitude-modulated decomposition structure with tin and copper, so that the strength of the copper alloy is remarkably improved; the zinc element can improve the fluidity of copper alloy melt, reduce segregation of the copper alloy and improve the structure uniformity of the cast ingot, so that the copper alloy cast ingot can obtain high-strength and high-hardness bronze through combined deformation.

Description

Technical Field

[0001] The invention relates to the technical field of copper alloy manufacturing, and in particular to an ultrafine-grained high-yield bronze and a preparation method thereof. Background Art

[0002] Bronze is an alloy made by adding tin or lead to pure copper (red copper). Bronze has the characteristics of low melting point, high hardness, strong plasticity, wear resistance, corrosion resistance and bright color. It is suitable for casting various utensils, mechanical parts, bearings and gears.

[0003] In recent years, with the rapid development of electronic technology, the uses and usage of various electronic and electrical equipment parts have become more and more extensive, such as terminal connectors, relays, contactors, contacts and other connectors. They are bridges between electronic and electrical components, and their role cannot be replaced by any other electronic components. As the core component of electrical connectors, connectors are the cornerstone of the bridge. At present, more than 90% of connectors are copper alloy strips, so the development of electrical connectors is inevitably inseparable from the development and innovation of copper alloy strips. At present, the copper alloys used in electrical connectors that are more widely used are mainly beryllium copper alloys, copper-nickel-silicon alloys and tin-phosphor bronze alloys. Among them, tin-phosphor bronze has the advantage of low price and is widely used, but due to its low tensile strength and yield strength, it can only be limited to low-end electrical connectors, which seriously limits its application in electronic technology.

[0004] Therefore, how to improve the tensile strength and yield strength of bronze has become a technical problem to be solved urgently in this field. Summary of the invention

[0005] The object of the present invention is to provide an ultrafine-grained high-yield bronze and a preparation method thereof. The ultrafine-grained high-yield bronze provided by the present invention has high tensile strength and yield strength.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The invention provides an ultrafine-grain high-yield bronze, which comprises the following chemical components by mass percentage: Sn: 8-11%, P: 0.03-0.35%, Fe: 0.001-0.1%, Ni: 0.001-0.1%, Zn: 0.001-0.2% and the balance of Cu.

[0008] The present invention provides a method for preparing the ultrafine-grained high-yield bronze described in the above technical solution, comprising the following steps:

[0009] (1) melting and horizontally continuously casting the alloy raw materials in sequence to obtain a bronze ingot;

[0010] (2) subjecting the bronze ingot obtained in step (1) to first homogenization annealing, preliminary rolling, second homogenization annealing and preliminary rolling in sequence to obtain a rolled strip;

[0011] (3) The rolled strip obtained in step (2) is subjected to a first bell-shaped annealing, a pre-finished product rolling, a continuous annealing, a finished product rolling and a second bell-shaped annealing in sequence to obtain an ultrafine-grained high-yield bronze.

[0012] Preferably, in the step (1), the temperature of the horizontal continuous casting is 1160-1210° C., and the pulling rate of the horizontal continuous casting is 140-200 mm / min.

[0013] Preferably, the temperature of the first homogenization annealing in step (2) is 500-670° C., and the holding time of the first homogenization annealing is 8-14 hours.

[0014] Preferably, the total deformation of the preliminary rolling in step (2) is 50-85%, and the preliminary rolling is cold rolling.

[0015] Preferably, the temperature of the second homogenization annealing in step (2) is 500-670° C., and the holding time of the second homogenization annealing is 8-14 hours.

[0016] Preferably, the total deformation of the initial rolling in step (2) is 50-85%, and the initial rolling is cold rolling.

[0017] Preferably, the temperature of the first bell-jar annealing in step (3) is 480-630° C., and the holding time of the first bell-jar annealing is 7-13 h.

[0018] Preferably, the temperature of continuous annealing in step (3) is 580-740° C., and the speed of continuous annealing is 25-75 m / min.

[0019] Preferably, the temperature of the second bell-jar annealing in step (3) is 180-350° C., and the holding time of the second bell-jar annealing is 5-12 hours.

[0020] The invention provides an ultrafine-grain high-yield bronze, which comprises the following chemical components by mass percentage: Sn: 8-11%, P: 0.03-0.35%, Fe: 0.001-0.1%, Ni: 0.001-0.1%, Zn: 0.001-0.2% and the balance of Cu. The present invention can form a continuous solid solution with Cu by adding Sn elements, and has a wide single-phase region, and they can significantly improve the mechanical properties and corrosion resistance of copper; by adding P elements, the fluidity of the melt can be improved, and the element segregation problem of the ingot can be significantly reduced. Moreover, the P element, as an effective deoxidizer for the copper alloy, reduces the adverse effects of oxygen in the copper alloy, thereby effectively improving the strength and hardness of the copper alloy. In addition, the P element can reduce product air absorption during horizontal continuous casting, and can improve the physical properties of the bronze; in addition, P can also form copper-phosphorus compounds with the Cu element in the copper alloy, hinder the growth of the copper alloy matrix grains at the grain boundary, thereby effectively refining the grains and improving the strength and hardness of the copper alloy; by adding trace Fe elements, the strength and hardness of the copper alloy can be significantly improved; by adding trace Ni elements, a modulated decomposition structure can be generated with Sn and Cu elements, thereby significantly improving the strength of the copper alloy; by adding trace Zn elements, the fluidity of the copper alloy melt can be improved, the segregation of the copper alloy can be reduced, and the structural uniformity of the ingot can be improved, which is more conducive to obtaining high-strength and high-hardness bronze through combined deformation of the copper alloy ingot. The results of the examples show that the ultrafine-grained high-yield bronze provided by the present invention has a tensile strength of more than 970 MPa and a yield strength of more than 930 MPa, and at the same time has high hardness and good ductility. DETAILED DESCRIPTION

[0021] The invention provides an ultrafine-grain high-yield bronze, which comprises the following chemical components by mass percentage: Sn: 8-11%, P: 0.03-0.35%, Fe: 0.001-0.1%, Ni: 0.001-0.1%, Zn: 0.001-0.2% and the balance of Cu.

[0022] The ultrafine grain high yield bronze provided by the present invention comprises Sn: 8-11% by mass percentage. The present invention can form a continuous solid solution with Cu by adding Sn element, and has a wide single-phase region, which can significantly improve the mechanical properties and corrosion resistance of copper. As an embodiment of the present invention, the mass content of Sn can be 8%, 8.5%, 9%, 9.5%, 10%, 10.5% or 11%.

[0023] In terms of mass percentage, the ultrafine-grained high-yield bronze provided by the present invention includes P: 0.03-0.35%. The present invention can improve the fluidity of the melt by adding the P element, significantly reduce the element segregation problem of the ingot, and the P element, as an effective deoxidizer for the copper alloy, reduces the adverse effects of oxygen in the copper alloy, thereby effectively improving the strength and hardness of the copper alloy. In addition, the P element can reduce product air absorption during horizontal continuous casting and improve the physical properties of the bronze; in addition, P can also form copper-phosphorus compounds with the Cu element in the copper alloy, hindering the growth of the copper alloy matrix grains at the grain boundaries, thereby effectively refining the grains and improving the strength and hardness of the copper alloy. As an embodiment of the present invention, the content of P can be 0.03%, 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, 0.18%, 0.2%, 0.22%, 0.25%, 0.28%, 0.3%, 0.32% or 0.35%.

[0024] The ultrafine grain high yield bronze provided by the present invention comprises Fe: 0.001-0.1% by mass percentage. The present invention can significantly improve the strength and hardness of the copper alloy by adding trace Fe elements. As an embodiment of the present invention, the content of Fe can be 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09% or 0.1%.

[0025] The ultrafine grain high yield bronze provided by the present invention comprises Ni: 0.001-0.1% by mass percentage. The present invention can generate a spinodal decomposition structure with Sn and Cu elements by adding a trace amount of Ni element, thereby significantly improving the strength of the copper alloy. As an embodiment of the present invention, the content of Ni can be 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09% or 0.1%.

[0026] The ultrafine grain high yield bronze provided by the present invention includes Zn: 0.001-0.2% by mass percentage. The present invention can improve the fluidity of the copper alloy melt, reduce the segregation of the copper alloy, improve the uniformity of the ingot structure by adding a trace amount of Zn element, and is more conducive to obtaining a high-strength and high-hardness bronze through combined deformation of the copper alloy ingot. As an embodiment of the present invention, the content of Zn can be 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, 0.18% or 0.2%.

[0027] In terms of mass percentage, the ultrafine grain high yield bronze provided by the present invention includes a balance of Cu. In the present invention, Cu is a matrix element of the alloy.

[0028] The present invention can form a continuous solid solution with Cu by adding Sn elements, and has a wide single-phase region, and they can significantly improve the mechanical properties and corrosion resistance of copper; by adding P elements, the fluidity of the melt can be improved, and the element segregation problem of the ingot can be significantly reduced. Moreover, the P element, as an effective deoxidizer for the copper alloy, reduces the adverse effects of oxygen in the copper alloy, thereby effectively improving the strength and hardness of the copper alloy. In addition, the P element can reduce product air absorption during horizontal continuous casting, and can improve the physical properties of the bronze; in addition, P can also form copper-phosphorus compounds with the Cu element in the copper alloy, hinder the growth of the copper alloy matrix grains at the grain boundary, thereby effectively refining the grains and improving the strength and hardness of the copper alloy; by adding trace Fe elements, the strength and hardness of the copper alloy can be significantly improved; by adding trace Ni elements, a modulated decomposition structure can be generated with Sn and Cu elements, thereby significantly improving the strength of the copper alloy; by adding trace Zn elements, the fluidity of the copper alloy melt can be improved, the segregation of the copper alloy can be reduced, and the structural uniformity of the ingot can be improved, which is more conducive to obtaining high-strength and high-hardness bronze through combined deformation of the copper alloy ingot.

[0029] The present invention also provides a method for preparing the ultrafine-grained high-yield bronze described in the above technical solution, comprising the following steps:

[0030] (1) melting and horizontally continuously casting the alloy raw materials in sequence to obtain a bronze ingot;

[0031] (2) subjecting the bronze ingot obtained in step (1) to first homogenization annealing, preliminary rolling, second homogenization annealing and preliminary rolling in sequence to obtain a rolled strip;

[0032] (3) The rolled strip obtained in step (2) is subjected to a first bell-shaped annealing, a pre-finished product rolling, a continuous annealing, a finished product rolling and a second bell-shaped annealing in sequence to obtain an ultrafine-grained high-yield bronze.

[0033] The invention sequentially smelts and horizontally continuously casts alloy raw materials to obtain bronze ingots.

[0034] In the present invention, the alloy raw materials preferably include pure nickel, electrolytic copper, copper-tin master alloy, copper-phosphorus 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 bronze. The present invention has no special restrictions on the specific composition of the copper-tin master alloy, copper-phosphorus 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 bronze, its composition is controllable, which can not only ensure that the chemical composition of the bronze meets the requirements, but also realize 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 1160-1210°C; the pulling rate of the horizontal continuous casting is preferably 140-200 mm / min. As an embodiment of the present invention, the temperature of the horizontal continuous casting can be 1160°C, 1170°C, 1180°C, 1190°C, 1200°C or 1210°C; the pulling rate of the horizontal continuous casting can be 140 mm / min, 150 mm / min, 160 mm / min, 170 mm / min, 180 mm / min, 190 mm / min or 200 mm / min.

[0037] After obtaining the bronze ingot, the present invention sequentially performs the first homogenization annealing, pre-rolling, the second homogenization annealing and the initial rolling on the bronze ingot to obtain a rolled strip.

[0038] In the present invention, the temperature of the first homogenization annealing is preferably 500-670°C; the holding time of the first homogenization annealing is preferably 8-14h. The present invention can reduce the element segregation inside the bronze ingot through homogenization annealing, making its chemical composition distribution more uniform. As an embodiment of the present invention, the temperature of the first homogenization annealing can be 500°C, 520°C, 550°C, 580°C, 600°C, 620°C, 650°C or 670°C; the holding time of the first homogenization annealing can be 8h, 9h, 10h, 11h, 12h, 13h or 14h.

[0039] In the present invention, the total deformation of the pre-rough rolling is preferably 50-85%; the pre-rough 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, which can be determined according to the technical common sense of the technicians in the field. The present invention uses pre-rough rolling to roll the bronze ingot with a large deformation. In this process, the casting defects inside the bronze ingot can be eliminated, and the coarse grains can be broken, which plays a role in refining the grains, thereby improving the mechanical properties of the bronze. As an embodiment of the present invention, the total deformation of the pre-rough rolling can be 50%, 55%, 60%, 65%, 70%, 75%, 80% or 85%; the deformation of the single pass of the pre-rough rolling can be 9-30%, and can also be 9%, 10%, 15%, 20%, 25% or 30%; the number of passes of the pre-rough rolling can be 10-15, and can also be 10, 11, 12, 13, 14 or 15.

[0040] In the present invention, the thickness of the product obtained by the preliminary rolling is preferably 3 to 9 mm.

[0041] In the present invention, the temperature of the second homogenization annealing is preferably 500-670°C; the holding time of the second homogenization annealing is preferably 8-14h. The present invention can make the internal structure of the alloy strip uniform through the second homogenization annealing treatment, and can reduce the strength and hardness of the alloy strip and improve its plasticity, so as to facilitate subsequent rolling.

[0042] The present invention preferably further comprises milling the product of the second homogenization annealing, and then performing initial rolling. 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.

[0043] In the present invention, the total deformation of the initial rolling is preferably 50-85%; 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 those skilled in the art. The present invention can further reduce the thickness of the bronze blank through initial rolling and further refine the grains inside it. As an embodiment of the present invention, the total deformation of the initial rolling can be 50%, 55%, 60%, 65%, 70%, 75%, 80% or 85%; 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.

[0044] In the present invention, the thickness of the initially rolled product is preferably 1 to 3.6 mm.

[0045] After the rolled strip is obtained, the invention sequentially performs the first bell-shaped annealing, pre-finished product rolling, continuous annealing, finished product rolling and the second bell-shaped annealing on the rolled strip to obtain ultrafine grain high yield bronze.

[0046] The present invention preferably trims the rolled strip first and then performs the first bell-shaped annealing. The present invention has no special limitation on the specific operation of 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. 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 after the blanking and initial rolling, thereby reducing the influence of oxygen on the plate and strip.

[0047] In the present invention, the temperature of the first bell-jar annealing is preferably 480-630°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, which can be determined according to the technical common sense of those skilled in the art, and can 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 can transform the processing structure of the material into a recrystallized structure on the other hand, 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 480°C, 500°C, 520°C, 540°C, 560°C, 580°C, 600°C or 630°C; the holding time of the first bell-jar annealing can be 7h, 8h, 9h, 10h, 11h, 12h or 13h.

[0048] The present invention preferably further comprises brushing the product of the first bell-jar annealing. 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.

[0049] After the brushing is completed, the present invention preferably further comprises performing intermediate rolling and intermediate continuous annealing on the brushed product in sequence. By introducing the process of intermediate rolling and intermediate continuous annealing, the present invention can further improve the tensile strength and yield strength of the bronze, while also having good elongation and bending performance.

[0050] 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.

[0051] In the present invention, the thickness of the product obtained by the intermediate rolling is preferably 0.3 to 1.5 mm.

[0052] In the present invention, the temperature of the intermediate continuous annealing is preferably 580-740°C; the speed of the intermediate continuous annealing is preferably 25-75 m / min. In the present invention, the grain size of the product of the intermediate continuous annealing is preferably 0.002-0.015 mm. The present invention has no special limitation on the atmosphere of the intermediate continuous annealing, as long as the bronze can be prevented from oxidizing during the annealing process. The present invention can improve the plasticity of the rolled alloy strip through the intermediate 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 intermediate continuous annealing may be 580°C, 600°C, 620°C, 640°C, 660°C, 680°C, 700°C, 720°C or 740°C; the speed of the intermediate continuous annealing may be 25m / min, 30m / min, 35m / min, 40m / min, 45m / min, 50m / min, 55m / min, 60m / min, 65m / min, 70m / min or 75m / min.

[0053] 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 pre-finished product rolling and the number of processing passes, which can be determined according to the technical common sense of the technicians in the field. The present invention can further reduce the size of the alloy strip by rolling the pre-finished product, and at the same time improve the uniformity of the structure of the alloy strip 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 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.

[0054] In the present invention, the thickness of the product obtained by rolling the pre-finished product is preferably 0.15 to 0.7 mm.

[0055] In the present invention, the temperature of the continuous annealing is preferably 580-740°C; the speed of the continuous annealing is preferably 25-75 m / min. In the present invention, the grain size of the product of the continuous annealing is preferably 0.002-0.015 mm. The present invention has no special limitation on the atmosphere of the continuous annealing, as long as the oxidation of the copper alloy strip during the annealing process can be avoided. Through continuous annealing, the present invention can improve the plasticity of the rolled copper alloy strip on the one hand, which is convenient for subsequent rolling, and on the other hand, make the grain size more uniform. As an embodiment of the present invention, the temperature of the continuous annealing may be 580°C, 600°C, 620°C, 640°C, 660°C, 680°C, 700°C, 720°C or 740°C; the speed of the continuous annealing may be 25m / min, 30m / min, 35m / min, 40m / min, 45m / min, 50m / min, 55m / min, 60m / min, 65m / min, 70m / min or 75m / min.

[0056] In the present invention, the total deformation of the finished product rolling is preferably 10-70%; the finished product rolling is preferably cold rolling. The present invention has no special limitation on the single-pass deformation and 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 copper alloy strip through finished product rolling, and at the same time improve the uniformity of the bronze structure and further improve its mechanical properties. As an embodiment of the present invention, the total deformation of the finished product rolling can be 10%, 20%, 30%, 40%, 50%, 60% or 70%; the single-pass deformation 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.

[0057] In the present invention, the thickness of the product obtained by rolling the finished product is preferably 0.05 to 0.63 mm.

[0058] The present invention preferably further comprises unwinding the finished rolled product. The present invention has no particular limitation on the specific operation of unwinding, and the unwinding operation of copper alloy strips well known to those skilled in the art can be used.

[0059] In the present invention, the temperature of the second bell-jar annealing is preferably 180-350°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, and it is sufficient to avoid oxidation of bronze during the annealing process. The present invention can remove residual stress in the alloy by performing bell-jar annealing on the one hand, and on the other hand, it plays a role of homogenization treatment, making the internal structure of the alloy more uniform, thereby further improving the strength and ductility of bronze. As an embodiment of the present invention, the temperature of the second bell-jar annealing can be 180°C, 200°C, 220°C, 240°C, 260°C, 280°C, 300°C, 330°C or 350°C; the holding time of the second bell-jar annealing can be 5h, 6h, 7h, 8h, 9h, 10h, 11h or 12h.

[0060] The present invention preferably further comprises pickling the product of the second bell-jar annealing. The present invention has no particular limitation on the specific operation of pickling and the composition of the pickling solution used, and conventional pickling operations 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.

[0061] The preparation method of the present invention controls the grain size of the pre-finished product to 0.0015-0.002 without adding any process steps, so that the final bronze has higher yield strength, higher elongation and better bending effect; by introducing intermediate rolling and intermediate continuous annealing, the grain size of the pre-finished product is controlled to be 0.0015-0.002, which can further improve the tensile strength and yield strength of the bronze.

[0062] 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.

[0063] Example 1

[0064] An ultrafine-grained high-yield bronze, the chemical composition of which is, by mass percentage, 8.3% Sn, 0.2% P, 0.0012% Fe, 0.044% Ni, 0.072% Zn and the balance Cu;

[0065] The method for preparing the ultrafine-grained high-yield bronze comprises the following steps:

[0066] (1) melting and horizontally continuously casting pure nickel, electrolytic copper, copper-tin master alloy, copper-phosphorus master alloy, copper-iron master alloy, pure zinc and recycled waste in sequence to obtain a bronze ingot; the temperature of the horizontal continuous casting is 1190° C., and the pulling rate of the horizontal continuous casting is 155 mm / min;

[0067] (2) The bronze ingot obtained in step (1) is subjected to first homogenization annealing, pre-rolling, second homogenization annealing, milling and pre-rolling in sequence to obtain a rolled strip; the temperature of the first homogenization annealing is 550° C., and the holding time of the first homogenization annealing is 14 h; the total deformation of the pre-rolling is 65%, the number of pre-rolling passes is 10, and the pre-rolling is cold rolling; the temperature of the second homogenization annealing is 570° C., and the holding time of the second homogenization annealing is 11 h; the total deformation of the pre-rolling is 72%, the number of pre-rolling passes is 10, and the pre-rolling is cold rolling;

[0068] (3) The rolled strip obtained in the step (2) is subjected to initial trimming, first bell-jar annealing, brushing, pre-finished product rolling, continuous annealing, finished product rolling, unwinding, second bell-jar annealing and pickling in sequence to obtain an ultrafine grain high yield bronze; the temperature of the first bell-jar annealing is 530° C., and the holding time of the first bell-jar annealing is 8 hours; the total deformation of the pre-finished product rolling is 80%, 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 continuous annealing is 660° C., the speed of the continuous annealing is 35 m / min, and the grain size of the product of the continuous annealing is 0.003 mm; 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 second bell-jar annealing is 240° C., and the holding time of the second bell-jar annealing is 12 hours.

[0069] Example 2

[0070] An ultrafine-grained high-yield bronze, the chemical composition of which is, by mass percentage, 9.5% Sn, 0.07% P, 0.007% Fe, 0.023% Ni, 0.024% Zn and the balance Cu;

[0071] The method for preparing the ultrafine-grained high-yield bronze comprises the following steps:

[0072] (1) melting and horizontally continuously casting pure nickel, electrolytic copper, copper-tin master alloy, copper-phosphorus master alloy, copper-iron master alloy, pure zinc and recycled waste in sequence to obtain a bronze ingot; the temperature of the horizontal continuous casting is 1190° C., and the pulling rate of the horizontal continuous casting is 155 mm / min;

[0073] (2) The bronze ingot obtained in step (1) is subjected to first homogenization annealing, pre-rolling, second homogenization annealing, milling and pre-rolling in sequence to obtain a rolled strip; the temperature of the first homogenization annealing is 550° C., and the holding time of the first homogenization annealing is 14 h; the total deformation of the pre-rolling is 65%, the number of pre-rolling passes is 10, and the pre-rolling is cold rolling; the temperature of the second homogenization annealing is 570° C., and the holding time of the second homogenization annealing is 11 h; the total deformation of the pre-rolling is 72%, the number of pre-rolling passes is 10, and the pre-rolling is cold rolling;

[0074] (3) The rolled strip obtained in the step (2) is subjected to initial trimming, first bell-jar annealing, brushing, pre-finished product rolling, continuous annealing, finished product rolling, unwinding, second bell-jar annealing and pickling in sequence to obtain an ultrafine grain high yield bronze; the temperature of the first bell-jar annealing is 530° C., and the holding time of the first bell-jar annealing is 8 hours; the total deformation of the pre-finished product rolling is 80%, 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 continuous annealing is 660° C., the speed of the continuous annealing is 35 m / min, and the grain size of the product of the continuous annealing is 0.003 mm; 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 second bell-jar annealing is 240° C., and the holding time of the second bell-jar annealing is 12 hours.

[0075] Example 3

[0076] An ultrafine-grained high-yield bronze, the chemical composition of which is, by mass percentage, 9.7% Sn, 0.25% P, 0.011% Fe, 0.033% Ni, 0.031% Zn and the balance Cu;

[0077] The method for preparing the ultrafine-grained high-yield bronze comprises the following steps:

[0078] (1) melting and horizontally continuously casting pure nickel, electrolytic copper, copper-tin master alloy, copper-phosphorus master alloy, copper-iron master alloy, pure zinc and recycled waste in sequence to obtain a bronze ingot; the temperature of the horizontal continuous casting is 1170° C., and the pulling rate of the horizontal continuous casting is 160 mm / min;

[0079] (2) The bronze ingot obtained in step (1) is subjected to first homogenization annealing, pre-rolling, second homogenization annealing, milling and pre-rolling in sequence to obtain a rolled strip; the temperature of the first homogenization annealing is 660° C., and the holding time of the first homogenization annealing is 11.5 h; the total deformation of the pre-rolling is 75%, the number of pre-rolling passes is 10, and the pre-rolling is cold rolling; the temperature of the second homogenization annealing is 600° C., and the holding time of the second homogenization annealing is 10 h; the total deformation of the pre-rolling is 65%, the number of pre-rolling passes is 10, and the pre-rolling is cold rolling;

[0080] (3) The rolled strip obtained in step (2) is sequentially subjected to initial trimming, first bell-shaped annealing, brushing, intermediate rolling, intermediate continuous annealing, pre-finished product rolling, continuous annealing, finished product rolling, unwinding, second bell-shaped annealing and pickling to obtain an ultrafine grain high yield bronze; the temperature of the first bell-shaped annealing is 540° 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; the temperature of the intermediate continuous annealing is 720° C., and the speed of the intermediate continuous annealing is 4 5m / min, the grain size of the product of the intermediate continuous annealing is 0.003mm; 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 continuous annealing is 700℃, the speed of the continuous annealing is 39m / min, and the grain size of the product of the continuous annealing is 0.002mm; the total deformation of the finished product rolling is 25%, the number of passes of the finished product rolling is 6, and the finished product rolling is cold rolling; the temperature of the second bell-type annealing is 270℃, and the holding time of the second bell-type annealing is 6h.

[0081] Comparative Example 1

[0082] A bronze having the chemical composition, by mass percentage, of Sn: 7.3%, P: 0.2%, Fe: 0.017%, Ni: 0.063%, Zn: 0.061% and the balance of Cu;

[0083] The method for preparing the bronze comprises the following steps:

[0084] (1) melting and horizontally continuously casting pure nickel, electrolytic copper, copper-tin master alloy, copper-phosphorus master alloy, copper-iron master alloy, pure zinc and recycled waste in sequence to obtain a bronze ingot; the temperature of the horizontal continuous casting is 1175° C., and the pulling rate of the horizontal continuous casting is 165 mm / min;

[0085] (2) The bronze ingot obtained in step (1) is subjected to first homogenization annealing, pre-rolling, second homogenization annealing, milling and pre-rolling in sequence to obtain a rolled strip; the temperature of the first homogenization annealing is 660° C., and the holding time of the first homogenization annealing is 12.5 h; the total deformation of the pre-rolling is 55%, the number of pre-rolling passes is 10, and the pre-rolling is cold rolling; the temperature of the second homogenization annealing is 630° C., and the holding time of the second homogenization annealing is 13 h; the total deformation of the pre-rolling is 61%, the number of pre-rolling passes is 10, and the pre-rolling is cold rolling;

[0086] (3) The rolled strip obtained in step (2) is subjected to initial trimming, first bell-shaped annealing, brushing, intermediate rolling, intermediate continuous annealing, pre-finished product rolling, continuous annealing, finished product rolling, unwinding, second bell-shaped annealing and pickling in sequence to obtain bronze; the temperature of the first bell-shaped annealing is 580° C., and the holding time of the first bell-shaped annealing is 9 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; the temperature of the intermediate continuous annealing is 720° C., and the speed of the intermediate continuous annealing is 25 m / s. min, the grain size of the product of the intermediate continuous annealing is 0.003mm; the total deformation of the pre-finished product rolling is 55%, 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 continuous annealing is 720°C, the speed of the continuous annealing is 30m / min, and the grain size of the product of the continuous annealing is 0.003mm; the total deformation of the finished product rolling is 33%, the number of passes of the finished product rolling is 6, and the finished product rolling is cold rolling; the temperature of the second bell-type annealing is 240°C, and the holding time of the second bell-type annealing is 6h.

[0087] Comparative Example 2

[0088] A bronze having the chemical composition, by mass percentage, of Sn: 9.5%, P: 0.01%, Fe: 0.015%, Ni: 0.023%, Zn: 0.011% and the balance of Cu;

[0089] The method for preparing the bronze comprises the following steps:

[0090] (1) melting and horizontally continuously casting pure nickel, electrolytic copper, copper-tin master alloy, copper-phosphorus master alloy, copper-iron master alloy, pure zinc and recycled waste in sequence to obtain a bronze ingot; the temperature of the horizontal continuous casting is 1165° C., and the pulling rate of the horizontal continuous casting is 155 mm / min;

[0091] (2) The bronze ingot obtained in step (1) is subjected to first homogenization annealing, pre-rolling, second homogenization annealing, milling and pre-rolling in sequence to obtain a rolled strip; the temperature of the first homogenization annealing is 670° C., and the holding time of the first homogenization annealing is 13.5 h; the total deformation of the pre-rolling is 55%, the number of pre-rolling passes is 10, and the pre-rolling is cold rolling; the temperature of the second homogenization annealing is 600° C., and the holding time of the second homogenization annealing is 12 h; the total deformation of the pre-rolling is 61%, the number of pre-rolling passes is 10, and the pre-rolling is cold rolling;

[0092] (3) The rolled strip obtained in step (2) is subjected to initial trimming, first bell-shaped annealing, brushing, intermediate rolling, intermediate continuous annealing, pre-finished product rolling, continuous annealing, finished product rolling, unwinding, second bell-shaped annealing and pickling in sequence to obtain bronze; the temperature of the first bell-shaped annealing is 600° C., and the holding time of the first bell-shaped annealing is 10 h; the total deformation of the intermediate rolling is 72%, the number of intermediate rolling passes is 8, and the intermediate rolling is cold rolling; the temperature of the intermediate continuous annealing is 720° C., and the speed of the intermediate continuous annealing is 30 m / s. / min, the grain size of the product of the intermediate continuous annealing is 0.001mm; the total deformation of the pre-finished product rolling is 55%, 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 continuous annealing is 720°C, the speed of the continuous annealing is 36m / min, and the grain size of the product of the continuous annealing is 0.01mm; the total deformation of the finished product rolling is 20%, the number of passes of the finished product rolling is 6, and the finished product rolling is cold rolling; the temperature of the second bell-type annealing is 270°C, and the holding time of the second bell-type annealing is 6h.

[0093] The properties of the bronze provided in Examples 1 to 3 and Comparative Examples 1 to 2 were tested, and the results obtained are shown in Table 1:

[0094] Table 1 Performance of bronze provided by Examples 1 to 3 and Comparative Examples 1 to 2

[0095] Tensile strength / MPa Yield strength / MPa <![CDATA[Elongation A 50 / %]]> Hardness / HV Comparative Example 1 744 688 6.5 241 Comparative Example 2 921 831 1.0 252 Example 1 882 834 5.0 248 Example 2 965 926 1.0 278 Example 3 973 934 1.0 280

[0096] Among them, the test methods for tensile strength and yield strength are: GB / T 34505-2017 Room temperature tensile test method;

[0097] The test method for elongation is: GB / T 34505-2017 room temperature tensile test method;

[0098] The test method for hardness is: GB / T 4340.1 Metallic materials Vickers hardness test Part 1: Test method.

[0099] It can be seen from Table 1 that when the chemical composition of bronze is not within the scope of the present invention, its tensile strength and yield strength are greatly reduced, such as the tensile strength and yield strength of comparative example 1 are significantly lower than those of embodiments 1 to 3 of the present invention; and according to the comparison between comparative example 2 and embodiments 1 to 3, it can be seen that the solution provided by the present invention can obtain bronze with high tensile strength and yield strength when using conventional processes, and if intermediate rolling and intermediate continuous annealing are introduced into the preparation process, the tensile strength and yield strength of bronze can be further improved (Example 3), and when the chemical composition of bronze is not within the scope of the present invention, even if the preparation process is optimized, bronze with high tensile strength and yield strength cannot be obtained (Comparative Example 1); through the comparison between Example 1 and Comparative Example 2, it can be seen that although the tensile strength of bronze is improved after the content of Sn element is increased, due to the change in element composition, the grain size of bronze after continuous annealing is 0.01 mm, and the grain size becomes larger, resulting in that the yield strength is not improved, which is only the same as that of Example 1, and is much lower than that of Examples 2 and 3. In summary, the present invention regulates the grain size of bronze by controlling the chemical composition and preparation process of bronze, thereby improving the tensile strength and yield strength of bronze.

[0100] 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. An ultrafine-grained high-yield bronze, comprising the following chemical components by mass percentage: Sn: 8-11%, P: 0.03-0.35%, Fe: 0.001-0.1%, Ni: 0.001-0.1%, Zn: 0.001-0.2% and the balance Cu.

2. The method for preparing the ultrafine-grained high-yield bronze according to claim 1, comprising the following steps: (1) melting and horizontally continuously casting the alloy raw materials in sequence to obtain a bronze ingot; (2) subjecting the bronze ingot obtained in step (1) to first homogenization annealing, preliminary rolling, second homogenization annealing and preliminary rolling in sequence to obtain a rolled strip; (3) The rolled strip obtained in step (2) is subjected to a first bell-shaped annealing, a pre-finished product rolling, a continuous annealing, a finished product rolling and a second bell-shaped annealing in sequence to obtain an ultrafine-grained high-yield bronze.

3. The preparation method according to claim 2, characterized in that: In the step (1), the temperature of the horizontal continuous casting is 1160-1210° C., and the pulling rate of the horizontal continuous casting is 140-200 mm / min.

4. The preparation method according to claim 2, characterized in that: The temperature of the first homogenization annealing in step (2) is 500-670° C., and the holding time of the first homogenization annealing is 8-14 hours.

5. The preparation method according to claim 2, characterized in that: The total deformation amount of the preliminary rolling in the step (2) is 50-85%, and the preliminary rolling is cold rolling.

6. The preparation method according to claim 2, characterized in that: The temperature of the second homogenization annealing in step (2) is 500-670° C., and the holding time of the second homogenization annealing is 8-14 hours.

7. The preparation method according to claim 2, characterized in that: The total deformation amount of the initial rolling in the step (2) is 50-85%, and the initial rolling is cold rolling.

8. The preparation method according to claim 2, characterized in that: The temperature of the first bell-jar annealing in step (3) is 480-630° C., and the holding time of the first bell-jar annealing is 7-13 hours.

9. The preparation method according to claim 2, characterized in that: The temperature of continuous annealing in step (3) is 580-740° C., and the speed of continuous annealing is 25-75 m / min.

10. The preparation method according to claim 2, characterized in that: The temperature of the second bell-jar annealing in step (3) is 180-350° C., and the holding time of the second bell-jar annealing is 5-12 hours.