A complex copper-nickel-tin alloy pipe and its manufacturing method and application

Abstract

This invention relates to a complex copper-nickel-tin alloy pipe, its manufacturing method, and its applications. The elemental composition of this complex copper-nickel-tin alloy pipe, by mass percentage, is: Ni: 5.0%–10.0%; Sn: 4.0%–8.0%; Zn: ≤1.0%; Zr: ≤0.2%; Fe: ≤0.1%; Pb: ≤0.1%; Al+Si<0.01%; Re: 0.005%–0.1%; the remainder being copper and unavoidable impurities. The alloy molten material is subjected to mechanical and electromagnetic stirring sequentially, followed by solidification into an ingot. The ingot is then subjected to hot extrusion, cold deformation, solution treatment, cryogenic treatment, and amplitude modulation decomposition treatment, resulting in a complex copper-nickel-tin alloy pipe with high strength, high yield strength, high hardness, high wear resistance, good impact toughness, and resistance to high-temperature oil vapor corrosion. The complex copper-nickel-tin alloy tubing has a tensile strength ≥800MPa, a yield strength ≥650MPa, a hardness ≥240HBW, an elongation ≥10%, and a grain size of 6-8.

Description

Technical Field

[0001] This invention relates to the field of metal smelting technology, and in particular to a complex copper-nickel-tin alloy tube, its manufacturing method, and its application. Background Technology

[0002] Copper-nickel-tin alloys are widely used in the manufacturing of connecting rod bushings for high-power internal combustion engines due to their high strength, hardness, high-temperature stability, good wear resistance, higher load-bearing capacity, and stronger anti-galling ability. Connecting rod bushings are components that connect the piston pin and the small end of the connecting rod in reciprocating piston engines. Their function is to prevent direct contact and wear between the piston pin and the small end of the connecting rod. At the same time, the connecting rod bushing must also withstand the alternating load of the piston pin and the inertial force of the connecting rod itself. Therefore, the connecting rod bushing is one of the main wear-prone components of an engine, and its reliability and service life directly affect the engine's overall reliability.

[0003] Chinese patent document CN 109477167 A, published on March 15, 2019, discloses a method for producing high-strength copper-nickel-tin alloy strip: continuous casting or semi-continuous casting of strip → strip annealing → multiple cold rolling of strip → multiple annealing of strip. To further obtain bushings, this method requires punching and rolling the strip, resulting in rolling seams.

[0004] Chinese patent document CN 117206841 A, published on December 12, 2023, discloses a processing method for high-strength, high-wear-resistant, and corrosion-resistant copper-nickel-tin alloy rods for bushings: copper-tin alloy rod blank → homogenization treatment → rolling → water-sealed extrusion → primary cold deformation → solution treatment → primary surface cleaning → secondary cold deformation → straightening → length cutting → aging treatment → secondary surface cleaning. This preparation method has a long process flow; the rod blank requires 16–30 hours of homogenization heat treatment and multiple cold deformations and surface cleanings. To further obtain bushings from this material preparation method, the rod must be drilled to form a hollow bushing. Summary of the Invention

[0005] In order to improve material utilization, reduce energy consumption, shorten process cycle, and improve the strength and wear resistance of pipes, this invention provides a complex copper-nickel-tin alloy pipe, its manufacturing method and application.

[0006] The technical solution provided by this invention is as follows:

[0007] The first aspect of this invention provides a complex copper-nickel-tin alloy tubing, the elemental composition of which, by mass percentage, is: Ni: 5.0%–10.0%; Sn: 4.0%–8.0%; Zn: ≤1.0%; Zr: ≤0.2%; Fe: ≤0.1%; Pb: ≤0.1%; Al+Si<0.01%; Re: 0.005%–0.1%; the remainder being copper and unavoidable impurities.

[0008] In conjunction with the first aspect of the present invention, in some embodiments, the elemental composition by mass percentage is: Ni: 5.0% to 8.0%; Sn: 4.5% to 7.0%; Zn: ≤0.85%; Zr: ≤0.16%; Fe: ≤0.09%; Pb: ≤0.08%; Al+Si<0.01%; Re: 0.005% to 0.085%; the remainder being copper and unavoidable impurities.

[0009] In conjunction with the first aspect of the present invention, in some embodiments, the preparation process of the complex copper-nickel-tin alloy tube is as follows: casting → hot extrusion → cold deformation → solution treatment → cryogenic treatment → amplitude modulation decomposition treatment.

[0010] In conjunction with the first aspect of the present invention, in some embodiments, the temperature of the hot extrusion is 850–980°C; and / or, the temperature of the cold deformation is room temperature; and / or, the temperature of the solution treatment is 650–850°C; and / or, the temperature of the amplitude modulation decomposition treatment is 350–400°C.

[0011] In conjunction with the first aspect of the present invention, in some embodiments, the complex copper-nickel-tin alloy tubing has a tensile strength ≥800MPa, a yield strength ≥650MPa, a hardness ≥240HBW, an elongation ≥10%, a matrix structure of α phase, and a grain size of 6-8.

[0012] A second aspect of the present invention provides a method for manufacturing a complex copper-nickel-tin alloy tubing, comprising:

[0013] The alloy raw materials are melted to obtain a liquid alloy;

[0014] The alloy liquid is subjected to vertical semi-continuous casting or horizontal continuous casting to obtain the as-cast alloy;

[0015] The as-cast alloy is subjected to hot extrusion, cold deformation, solution treatment, cryogenic treatment and amplitude modulation decomposition treatment in sequence to obtain complex copper-nickel-tin alloy pipes.

[0016] The manufacturing method of this complex copper-nickel-tin alloy tube mainly involves semi-continuous casting or horizontal continuous casting ingots, hot extrusion, cold deformation, solution treatment, deep cryogenic treatment, and amplitude modulation decomposition process, directly producing a seamless tube with superior performance. This tube can achieve dimensional accuracy far exceeding that of bushings obtained through rolling through machining.

[0017] In conjunction with the second aspect of the invention, some embodiments include:

[0018] The hot extrusion temperature is 850–980°C; and / or,

[0019] The temperature of the cold deformation is room temperature; and / or,

[0020] The solution treatment temperature is 650–850℃; the time is 2–8 hours; and the quenching medium is isothermal quenching oil or rapid quenching oil.

[0021] In conjunction with the second aspect of the invention, some embodiments include:

[0022] The cryogenic treatment is performed at a temperature of -180 to -90°C for 1 to 6 hours; and / or,

[0023] The amplitude modulation decomposition process is performed at a temperature of 350–400℃ for 3–6 hours.

[0024] In conjunction with the second aspect of the present invention, in some embodiments, the hot extrusion speed is 5 to 20 mm / s; the hot extrusion ratio λ is 10 to 40.

[0025] In conjunction with the second aspect of the present invention, in some embodiments, the cold deformation is cold rolling or cold drawing; the cold rolling deformation coefficient is 1.5 to 3.0; and the cold drawing deformation coefficient is 1.1 to 2.5.

[0026] In conjunction with the second aspect of the present invention, in some embodiments, a mechanical stirring device is provided on the top of the heat preservation furnace or intermediate transition bag, with a rotation speed of 30-100 r / min.

[0027] In conjunction with the second aspect of the present invention, in some embodiments, an electromagnetic device is circumferentially arranged on the outer periphery of the crystallizer of the vertical semi-continuous casting or horizontal continuous casting, the casting speed is 3-5 m / h, the electromagnetic stirring frequency is 5-20 Hz, and the electromagnetic stirring current is 80-200 A.

[0028] A third aspect of the present invention provides the application of the aforementioned complex copper-nickel-tin alloy tubular material in the manufacture of tubular wear-resistant parts, such as connecting rod bushings.

[0029] Compared with the prior art, the present invention has at least the following beneficial effects:

[0030] 1. The complex copper-nickel-tin alloy pipe manufactured by this invention does not contain the δ phase. The δ phase is a hard and brittle phase. When its content is high, it will affect the plasticity of the alloy, making the alloy prone to cracking during use, reducing the service life and reliability of the product. The complex copper-nickel-tin alloy pipe manufactured by this invention has high toughness and is not prone to cracking under subsequent large cold deformation coefficients (cold deformation). Furthermore, through solid solution treatment, deep cryogenic treatment and amplitude modulation decomposition treatment, the strength and elongation are greatly improved.

[0031] 2. The present invention performs a heat treatment process after the pipe is cut following cold deformation, which solves the limitation of heat treatment equipment caused by the excessive length of the pipe after thermoplastic molding.

[0032] 3. The heat treatment time of this invention is relatively short, which shortens the product manufacturing cycle.

[0033] 4. The present invention uses mechanical stirring and electromagnetic stirring during the smelting process to improve the purity and uniformity of the alloy liquid, reduce the need for subsequent homogenization heat treatment due to uneven composition, and reduce manufacturing costs and cycle time. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 The metallographic structure of the seamless tube in Example 1 after cold rolling and before solution treatment.

[0036] Figure 2 The metallographic structure of the seamless tube in Example 1 after amplitude modulation decomposition treatment.

[0037] Figure 3 The metallographic structure of the complex copper-nickel-tin alloy pipe obtained in Comparative Example 1 is shown.

[0038] Figure 4 The metallographic structure of the complex copper-nickel-tin alloy pipe obtained in Comparative Example 2 is shown. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0040] For simplicity, this invention only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form a range not explicitly stated; and any lower limit can be combined with other lower limits to form a range not explicitly stated; similarly, any upper limit can be combined with any other upper limit to form a range not explicitly stated. Furthermore, although not explicitly stated, every point or individual value between the endpoints of the range is included within that range. Therefore, each point or individual value can be used as its own lower or upper limit and combined with any other point or individual value or with other lower or upper limits to form a range not explicitly stated.

[0041] It should be noted that, in the description of this invention, unless otherwise stated, "above" and "below" include the stated number, and "multiple" in "one or more" means two or more. Relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0042] In the description of this invention, the terms "any embodiment / mode," "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment / mode or example, which are included in at least one embodiment / mode or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0043] The above description of the invention is not intended to describe every disclosed embodiment or implementation of the invention. Exemplary embodiments are described in more detail below. These embodiments can be used in various combinations. In each example, the listing is merely representative and should not be construed as exhaustive.

[0044] Complex copper-nickel-tin alloy tubing:

[0045] The complex copper-nickel-tin alloy tubing provided by this invention has the following elemental composition by mass percentage: Ni: 5.0%–10.0%; Sn: 4.0%–8.0%; Zn: ≤1.0%; Zr: ≤0.2%; Fe: ≤0.1%; Pb: ≤0.1%; Al+Si<0.01%; Re: 0.005%–0.1%; 其 The remainder consists of copper and unavoidable impurities. This complex copper-nickel-tin alloy tubing exhibits a tensile strength ≥800 MPa, yield strength ≥650 MPa, hardness ≥240 HBW, elongation ≥10%, and a matrix structure of... α Phase, grain size 6-8.

[0046] Preferably, the elemental composition of the complex copper-nickel-tin alloy tubing provided by the present invention, by mass percentage, is as follows: Ni: 5.0%–8.0%; Sn: 4.5%–7.0%; Zn: ≤0.85%; Zr: ≤0.16%; Fe: ≤0.09%; Pb: ≤0.08%; Al+Si<0.01%; Re: 0.005%–0.085%; the remainder being copper and unavoidable impurities.

[0047] In some embodiments of the present invention, the preparation process of the complex copper-nickel-tin alloy tube is as follows: casting → hot extrusion → cold deformation → solution treatment → cryogenic treatment → amplitude modulation decomposition treatment. Preferably, the temperature of the hot extrusion is 850–980°C; the temperature of the cold deformation is room temperature; the temperature of the solution treatment is 650–850°C; the time is 2–8 hours; the quenching medium is isothermal quenching oil or rapid quenching oil; the temperature of the cryogenic treatment is -180–-90°C; the time is 1–6 hours; and the temperature of the amplitude modulation decomposition treatment is 350–400°C; the time is 3–6 hours.

[0048] This invention adds rare earth element Re to complex copper-nickel-tin alloy pipes. On the one hand, rare earth elements have low solid solubility in copper and easily form high-melting-point compounds with other elements, which can become dispersed heterogeneous nucleation cores, thereby refining grains, reducing columnar crystal regions, and improving the ingot structure. On the other hand, rare earth elements easily react with oxygen, hydrogen, nitrogen, sulfur, and impurities such as lead and bismuth to form slag, which can degas, remove impurities, and purify the melt, thereby improving the mechanical properties and wear resistance of complex copper-nickel-tin alloy pipes and their products.

[0049] The complex copper-nickel-tin alloy tubing of this invention strictly controls the Al and Si content, and adds an appropriate amount of Zn to improve the fluidity of the alloy liquid while reducing the anti-segregation of tin bronze and inhibiting the generation of β phase, which is beneficial for cold deformation at room temperature.

[0050] The addition of small amounts of Zr and Fe elements to the complex copper-nickel-tin alloy pipe of the present invention can reduce the grain growth rate, inhibit cell nucleation and growth, shorten the amplitude modulation decomposition strengthening time, and enhance the precipitation strengthening effect.

[0051] The complex copper-nickel-tin alloy tubing of this invention has sufficient hardness, strength, and wear resistance, and can withstand a certain amount of impact, and has a certain degree of toughness.

[0052] Manufacturing method:

[0053] The method for manufacturing complex copper-nickel-tin alloy tubing provided by this invention includes:

[0054] The alloy raw materials are melted to obtain a liquid alloy;

[0055] The alloy liquid is subjected to vertical semi-continuous casting or horizontal continuous casting to obtain the as-cast alloy;

[0056] The as-cast alloy was subjected to hot extrusion, cold deformation, solution treatment, cryogenic treatment, and amplitude modulation decomposition treatment in sequence to obtain the aforementioned complex copper-nickel-tin alloy tubing.

[0057] The manufacturing method of this invention first obtains seamless tubing through hot extrusion; then, it obtains the required dimensions through cold deformation, and further refines the grains in the matrix through solid solution treatment to eliminate stress and restore plasticity; then, it further dissolves Ni and Sn into the matrix through deep cryogenic treatment; finally, it performs amplitude modulation decomposition, resulting in a significant increase in material strength. The principle of amplitude modulation decomposition treatment is as follows: after the alloy undergoes solid solution treatment, elements such as Ni and Sn dissolve into the copper matrix, forming a supersaturated solid solution. During subsequent cooling, these elements do not spontaneously precipitate but require heating to a certain temperature to form two solid solutions with the same structure but periodic fluctuations in composition through uphill diffusion of solute atoms. This process does not involve a nucleation stage, does not produce another crystal structure, and does not have a clear phase interface. It is a solid-state phase transition in which new phases are directly formed by the fluctuations in composition. Optically, the two phases cannot be distinguished, and the metallographic structure remains unchanged, which is reflected in the change in hardness.

[0058] This invention directly forms seamless tubes through a one-time hot extrusion process. After hot extrusion, cold deformation, solution treatment, deep cryogenic treatment, and amplitude modulation decomposition, the as-cast alloy microstructure has a grain size of 6-8. There is no continuous or discontinuous hard and brittle δ phase in the microstructure. Elements such as Sn and Ni diffuse into the α phase solid solution. Through amplitude modulation decomposition treatment, the strength and elongation are greatly improved.

[0059] The complex copper-nickel-tin alloy tubing of this invention strictly controls the Al and Si content, and adds an appropriate amount of Zn to improve the fluidity of the alloy liquid while reducing the anti-segregation of tin bronze and inhibiting the formation of the β phase, which is beneficial for cold deformation at room temperature; adding a small amount of Zr and Fe elements can reduce the grain growth rate, inhibit cell nucleation and growth, shorten the amplitude modulation decomposition strengthening time, and enhance the precipitation strengthening effect.

[0060] Furthermore, this invention optimizes the process flow during the forming process and optimizes process parameters such as hot extrusion speed, hot extrusion ratio, and cold rolling deformation amount to ensure that the tube does not produce defects such as cracks after one cold rolling process, eliminating the need for multiple cold rolling processes. At the same time, since the tube is relatively long after hot deformation, this invention performs a heat treatment process after the tube is cut by cold deformation, overcoming the limitation that heat treatment equipment cannot handle long tubes.

[0061] To address the issue of homogenization of molten alloy, this invention introduces mechanical and electromagnetic stirring processes during casting. Under the dual action of electromagnetic and mechanical stirring, the distribution of easily segregated Sn elements in the molten alloy is improved, making it fully homogenized. At the same time, the grains are refined, resulting in high-quality cast alloy ingots or tubes. This eliminates the need for the long-term homogenization heat treatment process required after conventional casting of this type of alloy, significantly shortening the manufacturing cycle.

[0062] In some embodiments of the present invention, the temperature of the hot extrusion is 850–980°C; and / or the temperature of the cold rolling is room temperature; and / or the temperature of the cold drawing is room temperature; and / or the temperature of the solution treatment is 650–850°C; the temperature of the cryogenic treatment is -180–-90°C; and the temperature of the amplitude modulation decomposition treatment is 350–400°C.

[0063] In some embodiments of the present invention, the alloy liquid is subjected to vertical semi-continuous casting or horizontal continuous casting, including: using a crystallizer specially equipped with an electromagnetic stirrer to perform vertical semi-continuous casting or horizontal continuous casting of the above alloy liquid to obtain a cast alloy.

[0064] Some embodiments of the present invention ， A mechanical stirring device is installed on the top of the heat preservation furnace or intermediate transition package, with a rotation speed of 30-100 r / min.

[0065] In some embodiments of the present invention, the crystallizer of the vertical semi-continuous casting or horizontal continuous casting is provided with an electromagnetic stirring device along the circumference, the casting speed is 3-5 m / h, the electromagnetic stirring frequency is 5-20 Hz, and the electromagnetic stirring current is 80-200 A.

[0066] In some embodiments of the present invention, the hot extrusion speed is 5 to 20 mm / s; the hot extrusion ratio λ is 10 to 40.

[0067] In some embodiments of the present invention, the cold rolling deformation coefficient is 1.5 to 3.0.

[0068] In some embodiments of the present invention, the cold-drawing deformation coefficient is 1.1 to 2.5.

[0069] In some embodiments of the present invention, the solution treatment time is 2 to 8 hours; the cryogenic treatment time is 1 to 6 hours; and the amplitude modulation decomposition treatment time is 3 to 6 hours.

[0070] In some embodiments of the present invention, the smelting of the alloy raw materials includes: melting the alloy raw materials, heating the alloy liquid to boiling while stirring, and then adding a refining agent to remove slag. Specifically: after all the alloy raw materials have been melted, the mixture is heated to boiling for 2-3 minutes using electromagnetic stirring in a medium-frequency furnace, and a special refining agent DCQT-X2 is added at a concentration of 0.5 wt% of the copper liquid. After standing for 3-5 minutes, the slag is removed.

[0071] application:

[0072] As described above, the complex copper-nickel-tin alloy tubing can be manufactured into seamless tubing using the above method. This seamless tubing has high strength, high yield strength, high hardness, high wear resistance, good impact toughness, and resistance to high-temperature oil and gas corrosion, making it suitable for manufacturing connecting rod bushings, such as connecting rod bushings for heavy-duty vehicles.

[0073] Currently, the main manufacturing process for connecting rod bushings abroad generally involves continuous casting or semi-continuous casting of sheet metal. To further produce bushings from this material, the sheet metal must be punched and rolled, resulting in seams during the rolling process. The connecting rod bushing manufacturing process disclosed in this invention primarily involves semi-continuous casting or horizontal continuous casting of ingots, hot extrusion, cold deformation, solution treatment, cryogenic treatment, and amplitude modulation decomposition processing, directly manufacturing a seamless tube with superior performance. This tube can achieve dimensional accuracy far exceeding that obtained through rolling methods.

[0074] The technical solution of the present invention is described in detail below through embodiments. Unless otherwise specified, the raw materials, equipment, or solvents used are all commercially available. Unless otherwise specified, the raw materials with the same name used in the following embodiments and comparative examples are the same raw materials.

[0075] In the following examples and comparative examples, the copper material has a Cu purity of 99.9%, the Ni material is elemental nickel, the Sn material is elemental tin, and the rare earth material is a rare earth copper alloy.

[0076] Example 1:

[0077] The manufacturing method of complex copper-nickel-tin alloy tubing provided in this embodiment includes:

[0078] (1) Casting: According to the chemical composition shown in Table 1, copper material with a Cu purity of 99.9% is first heated and melted to form copper liquid; then nickel is added in batches; after the nickel is completely melted, a small amount of other alloys such as tin are added, and finally rare earth copper alloy is added. After it is completely melted, tin bronze DCQT-X2 refining slag remover is added, with an addition amount of 0.5wt% of copper liquid. Stir and remove slag to obtain alloy liquid; transfer the alloy liquid to the intermediate transition ladle, and perform strong stirring of the alloy liquid under the action of mechanical stirring motor, setting the speed to 40r / min; vertical semi-continuous casting is carried out, the alloy liquid enters the crystallizer, and after the bottom solidifies and forms, the function of the specially installed electromagnetic stirrer is turned on, the electromagnetic stirring frequency is 15Hz, the electromagnetic stirring current is 148A, the casting speed is 4.5m / h, and the as-cast alloy ingot is obtained.

[0079] (2) Hot extrusion: The cast alloy ingot is heated to 930°C, and the hot extrusion speed is set to 20 mm / s and the hot extrusion ratio is 25 to obtain a seamless tube.

[0080] (3) Cold rolling: Seamless tubes are cold rolled at room temperature with a cold rolling deformation coefficient of 1.85.

[0081] (4) Solution treatment: The seamless tube after cold rolling is subjected to solution treatment. The solution treatment temperature is 800℃, the holding time is 2h, and the quenching medium is isothermal quenching oil.

[0082] (5) Cryogenic treatment: Temperature: -100℃, holding time: 3h.

[0083] (6) Amplitude modulation decomposition process: heating temperature: 370℃, holding time: 4h, to obtain complex copper-nickel-tin alloy pipe.

[0084] Example 2:

[0085] The manufacturing method of complex copper-nickel-tin alloy tubing provided in this embodiment includes:

[0086] (1) Casting: According to the chemical composition shown in Table 1, copper material with a Cu purity of 99.9% is first heated and melted to form copper liquid; then nickel is added to the copper liquid in batches; after the nickel is completely melted, a small amount of other alloys such as tin are added, and finally rare earth copper alloy is added. After it is completely melted, tin bronze DCQT-X2 refining slag remover is added, with an addition amount of 0.5wt% of copper liquid. Stir and remove slag to obtain alloy liquid; transfer the alloy liquid to the intermediate transition ladle, and perform strong stirring of the alloy liquid under the action of mechanical stirring motor, setting the speed to 30r / min; perform horizontal continuous casting, the alloy liquid enters the crystallizer, and after the bottom solidifies, the function of the specially installed electromagnetic stirrer is turned on, with an electromagnetic stirring frequency of 15Hz, an electromagnetic stirring current of 152A, and a casting speed of 3.5m / h to obtain cast alloy ingot.

[0087] (2) Hot extrusion: The cast alloy ingot is heated to 880°C, and the hot extrusion speed is set to 15 mm / s and the hot extrusion ratio is 20.6 to obtain a seamless tube.

[0088] (3) Cold rolling: Seamless tubes are cold rolled at room temperature with a cold rolling deformation coefficient of 1.85.

[0089] (4) Solution treatment: The seamless tube after cold rolling is subjected to solution treatment. The solution treatment temperature is 750℃, the holding time is 2.5h, and the quenching medium is isothermal quenching oil.

[0090] (5) Cryogenic treatment: Temperature: -120℃, holding time: 2h.

[0091] (6) Amplitude modulation decomposition process: heating temperature: 380℃, holding time: 4h, to obtain complex copper-nickel-tin alloy pipe.

[0092] Example 3:

[0093] The manufacturing method of complex copper-nickel-tin alloy tubing provided in this embodiment includes:

[0094] (1) Casting: According to the chemical composition shown in Table 1, copper material with a Cu purity of 99.9% is first heated and melted to form copper liquid; then nickel is added to the copper liquid in batches; after the nickel is completely melted, a small amount of other alloys such as tin are added, and finally rare earth copper alloy is added. After it is completely melted, tin bronze DCQT-X2 refining slag remover is added, with an addition amount of 0.5wt% of copper liquid. Stir and remove slag to obtain alloy liquid; transfer the alloy liquid to the intermediate transition ladle, and perform strong stirring of the alloy liquid under the action of mechanical stirring motor, setting the speed to 60r / min; vertical semi-continuous casting is carried out, the alloy liquid enters the crystallizer, and after the bottom solidifies, the function of the specially installed electromagnetic stirrer is turned on, with an electromagnetic stirring frequency of 12Hz, an electromagnetic stirring current of 150A, and a casting speed of 4m / h to obtain the cast alloy ingot.

[0095] (2) Hot extrusion: The cast alloy ingot is heated to 885°C, and the hot extrusion speed is set to 15 mm / s and the hot extrusion ratio is 13.5 to obtain a seamless tube.

[0096] (3) Cold drawing: Seamless tubes are cold drawn at room temperature, and the cold drawing deformation coefficient is 1.35.

[0097] (4) Solution treatment: The seamless tube after cold rolling is subjected to solution treatment. The solution treatment temperature is 720℃, the holding time is 3.5h, and the quenching medium is rapid quenching oil.

[0098] (5) Cryogenic treatment: Temperature: -120℃, holding time: 2h.

[0099] (6) Amplitude modulation decomposition process: heating temperature: 360℃, holding time: 4.5h, to obtain complex copper-nickel-tin alloy pipe.

[0100] Example 4:

[0101] The manufacturing method of complex copper-nickel-tin alloy tubing provided in this embodiment includes:

[0102] (1) Casting: First, heat and melt copper material with a Cu purity of 99.9% to form copper liquid; then add nickel in batches; after the nickel is completely melted, add a small amount of other alloys such as tin, and finally add rare earth copper alloy. After it is completely melted, add tin bronze DCQT-X2 refining slag remover, the amount of which is 0.5wt% of the copper liquid. Stir and remove slag to obtain alloy liquid; transfer the alloy liquid to the intermediate transition ladle, and perform strong stirring of the alloy liquid under the action of mechanical stirring motor, setting the speed to 38r / min; perform horizontal continuous casting, the alloy liquid enters the crystallizer, and after the bottom solidifies, turn on the function of the specially installed electromagnetic stirrer, the electromagnetic stirring frequency is 18Hz, the electromagnetic stirring current is 156A, the casting speed is 4.8m / h, and the as-cast alloy ingot is obtained.

[0103] (2) Hot extrusion: The cast alloy ingot is heated to 880°C, and the hot extrusion speed is set to 16 mm / s and the hot extrusion ratio is 17.5 to obtain a seamless tube.

[0104] (3) Cold drawing: Seamless tubes are cold drawn at room temperature, and the cold drawing deformation coefficient is 1.13.

[0105] (4) Solution treatment: The seamless tube after cold rolling is subjected to solution treatment. The solution treatment temperature is 680℃ and the holding time is 6h. The quenching medium is rapid quenching oil.

[0106] (5) Cryogenic treatment: Temperature: -140℃, holding time: 1.5h.

[0107] (6) Amplitude modulation decomposition process: heating temperature: 375℃, holding time: 4.5h, to obtain complex copper-nickel-tin alloy pipe.

[0108] Comparative Example 1

[0109] Compared with Example 1, this comparative example does not involve mechanical or electromagnetic stirring during the casting process. The specific method for manufacturing complex copper-nickel-tin alloy tubing provided is as follows:

[0110] (1) Casting: According to the chemical composition of Example 1, copper material with a Cu purity of 99.9% is heated and melted to form copper liquid; then nickel is added in batches; after the nickel is completely melted, a small amount of other alloys such as tin are added, and finally rare earth copper alloy is added. After it is completely melted, tin bronze DCQT-X2 refining and slag removal agent is added, with an addition amount of 0.5wt% of copper liquid. Stir and remove slag to obtain alloy liquid; transfer the alloy liquid to the intermediate transition ladle for vertical semi-continuous casting at a casting speed of 4.5m / h to obtain cast alloy ingot.

[0111] (2) Hot extrusion: The cast alloy ingot is heated to 930°C, and the hot extrusion speed is set to 20 mm / s and the hot extrusion ratio is 25 to obtain a seamless tube.

[0112] (3) Cold rolling: Seamless tubes are cold rolled at room temperature with a cold rolling deformation coefficient of 1.85.

[0113] (4) Solution treatment: The seamless tube after cold rolling is subjected to solution treatment. The solution treatment temperature is 800℃, the holding time is 2h, and the quenching medium is isothermal quenching oil.

[0114] (5) Cryogenic treatment: Temperature: -100℃, holding time: 3h.

[0115] (6) Amplitude modulation decomposition process: heating temperature: 370℃, holding time: 4h, to obtain complex copper-nickel-tin alloy pipe.

[0116] Comparative Example 2

[0117] Compared with Example 1, this comparative example increases the solution treatment temperature, and the specific method for manufacturing complex copper-nickel-tin alloy tubing is as follows:

[0118] (1) Casting: According to the chemical composition of Example 1, copper material with a Cu purity of 99.9% is first heated and melted to form copper liquid; then nickel is added in batches; after the nickel is completely melted, a small amount of other alloys such as tin are added, and finally rare earth copper alloy is added. After it is completely melted, tin bronze DCQT-X2 refining and slag removal agent is added, with an addition amount of 0.5wt% of copper liquid. Stir and remove slag to obtain alloy liquid; transfer the alloy liquid to the intermediate transition ladle, and perform strong stirring of the alloy liquid under the action of mechanical stirring motor, setting the speed to 40r / min; vertical semi-continuous casting is carried out, the alloy liquid enters the crystallizer, and after the bottom solidifies and forms, the function of the specially installed electromagnetic stirrer is turned on, the electromagnetic stirring frequency is 15Hz, the electromagnetic stirring current is 148A, the casting speed is 4.5m / h, and the as-cast alloy ingot is obtained.

[0119] (2) Hot extrusion: The cast alloy ingot is heated to 930°C, and the hot extrusion speed is set to 20 mm / s and the hot extrusion ratio is 25 to obtain a seamless tube.

[0120] (3) Cold rolling: Seamless tubes are cold rolled at room temperature with a cold rolling deformation coefficient of 1.85.

[0121] (4) Solution treatment: The seamless tube after cold rolling is subjected to solution treatment at a temperature of 860℃ and a holding time of 2.5h. The quenching medium is isothermal quenching oil.

[0122] (5) Cryogenic treatment: Temperature: -100℃, holding time: 3h.

[0123] (6) Amplitude modulation decomposition process: heating temperature: 370℃, holding time: 4h, to obtain complex copper-nickel-tin alloy pipe.

[0124] The complex copper-nickel-tin alloy tubes manufactured in the above embodiments and comparative examples were subjected to hardness testing under the HRB test conditions according to GB / T230.1-2018. Mechanical property tests were conducted under the GB / T 228B test conditions using the GB / T 228.1-2010 test method. Metallographic analysis was performed according to GB / T15749-2008 and YS / T 449-2002. A point contact cyclic reciprocating friction and wear tester and a rotary friction PV tester were used. The friction and wear test conditions were: normal force: 200N, ambient temperature: 150℃±2℃, oscillation frequency: 10Hz, stroke length: 10mm, lubrication: 80W-90GL4, test time: 33min20s (sliding distance 400m). The wear depth of the samples was measured using a three-dimensional profilometer. Specific test results are shown in the table below.

[0125] Table 1 Chemical Composition

[0126]

[0127]

[0128] Table 2 Mechanical properties and wear resistance / sintering resistance

[0129]

[0130] As shown in Table 2, the complex copper-nickel-tin alloy tubing prepared in Examples 1 to 4 of the present invention has a hardness of 262 to 280 HB, a yield strength of 713 to 783 MPa, a tensile strength of 857 to 887 MPa, a friction coefficient of 0.114 to 0.119, and a PV value of 22.1 to 26.7 MPa*m / s.

[0131] A high PV value for a material indicates good resistance to sintering, meaning it can maintain good mechanical sealing performance even under high pressure and high speed.

[0132] Figure 1The metallographic structure of the seamless tube in Example 1 after cold rolling and before solution treatment is shown. The matrix structure is α phase, and the black part is α+δ phase. The structure has a high tendency to be brittle.

[0133] Figure 2 The metallographic structure of the seamless tube in Example 1 after amplitude modulation decomposition is shown. The matrix structure is α phase, without δ phase, with a grain size of 7.5 grade and no obvious segregation. This seamless tube has good toughness, is not prone to cracking during use, and has good product reliability and long service life.

[0134] Figure 3 The metallographic structure of the complex copper-nickel-tin alloy pipe obtained in Comparative Example 1 is shown. The matrix structure is α phase. The obvious segregation in the matrix structure indicates that the lack of mechanical and electromagnetic stirring will lead to uneven dispersion of elements in the solution.

[0135] Figure 4 The metallographic structure of the complex copper-nickel-tin alloy pipe obtained in Comparative Example 2 shows that the grains in the matrix are significantly grown and a large number of black patchy eutectoid phases are present, indicating that increasing the solid solution temperature to 860℃ will lead to abnormal grain growth in the alloy.

[0136] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A complex copper-nickel-tin alloy pipe, characterized in that: The elemental composition by mass percentage is: Ni: 5.0%~10.0%; Sn: 4.0%~8.0%; Zn: ≤1.0%; Zr：0.05%~0.2%； Fe: 0.022%~0.1%; Pb: ≤0.1%; Al+Si<0.01%; Re: 0.005%~0.1%; the remainder is copper and unavoidable impurities; wherein Zn, Pb, and Al+Si are not 0; the preparation process of the complex copper-nickel-tin alloy pipe is: casting → hot extrusion → cold deformation → solution treatment → cryogenic treatment → amplitude modulation decomposition treatment; wherein the temperature of the hot extrusion is 850~980℃; the temperature of the cold deformation is room temperature; the temperature of the solution treatment is 650~850℃; the temperature of the amplitude modulation decomposition treatment is 350~400℃.

2. The complex copper-nickel-tin alloy tubing according to claim 1, characterized in that: The elemental composition by mass percentage is: Ni: 5.0%–8.0%; Sn: 4.5%~7.0%; Zn: ≤0.85%; Zr: 0.05%~0.16%; Fe: 0.022%~0.09%; Pb: ≤0.08%; Al+Si<0.01%; Re: 0.005%~0.085%; the remainder is copper and unavoidable impurities; among which, Zn, Pb, and Al+Si are not 0.

3. A method for manufacturing a complex copper-nickel-tin alloy pipe, characterized in that, include: The alloy raw materials are melted to obtain a liquid alloy; The alloy liquid is subjected to vertical semi-continuous casting or horizontal continuous casting to obtain the as-cast alloy; The as-cast alloy is subjected to hot extrusion, cold deformation, solution treatment, cryogenic treatment and amplitude modulation decomposition treatment in sequence to obtain the complex copper-nickel-tin alloy pipe as described in claim 1.

4. The method for manufacturing complex copper-nickel-tin alloy tubing according to claim 3, characterized in that: A mechanical stirring device is installed on the top of the heat preservation furnace or intermediate transition package, with a rotation speed of 30~100 r / min.

5. The method for manufacturing complex copper-nickel-tin alloy tubing according to claim 3, characterized in that: An electromagnetic device is installed along the circumference of the crystallizer. The electromagnetic stirring frequency is 5-20Hz, the electromagnetic stirring current is 80-200A, and the casting speed is 3-5m / h.

6. The method for manufacturing complex copper-nickel-tin alloy tubing according to claim 3, characterized in that: The hot extrusion temperature is 850–980℃; the hot extrusion speed is 5–20 mm / s; and the hot extrusion ratio λ is 10–40.

7. The method for manufacturing complex copper-nickel-tin alloy tubing according to claim 3, characterized in that: The temperature at which the cold deformation is performed is room temperature; Cold deformation is either cold rolling or cold drawing. The deformation coefficient for cold rolling is 1.5 to 3.0; the deformation coefficient for cold drawing is 1.1 to 2.

5.

8. The method for manufacturing complex copper-nickel-tin alloy tubing according to claim 3, characterized in that: The solution treatment temperature is 650–850℃; the time is 2–8 hours; the quenching medium is isothermal quenching oil or rapid quenching oil; and / or, The cryogenic treatment is performed at a temperature of -180 to -90°C for 1 to 6 hours; and / or, The amplitude modulation decomposition process is performed at a temperature of 350–400℃ for 3–6 hours.

9. The application of the complex copper-nickel-tin alloy tubing as described in claim 1 or 2 in the manufacture of tubular wear-resistant parts.

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