Complex copper-nickel-tin alloy pipe and manufacturing method and application thereof

Abstract

The invention relates to a complex copper-nickel-tin alloy pipe and a manufacturing method and application thereof. The complex copper-nickel-tin alloy pipe comprises the following elements in percentage by mass: 5.0%-10.0% of Ni; 4.0% to 8.0% of Sn; zn: less than or equal to 1.0%; zr: less than or equal to 0.2%; fe: less than or equal to 0.1%; less than or equal to 0.1% of Pb; al + Si is less than 0.01%; 0.005% to 0.1% of Re; and the balance of copper and inevitable impurities. The alloy melt is sequentially subjected to mechanical stirring and electromagnetic stirring and solidified to form a cast ingot, the cast ingot is sequentially subjected to hot extrusion, cold deformation, solution treatment, subzero treatment and amplitude modulation decomposition treatment, and the complex copper-nickel-tin alloy pipe with high strength, high yield, high hardness, high wear resistance, good impact toughness and high-temperature oil vapor corrosion resistance can be obtained. The tensile strength of the complex copper-nickel-tin alloy pipe is larger than or equal to 800 MPa, the yield strength is larger than or equal to 650 MPa, the hardness is larger than or equal to 240 HBW, the ductility is larger than or equal to 10%, and the grain size is 6-8 grades.

Description

Technical Field

[0001] The invention relates to the technical field of metal smelting, and in particular to a complex copper-nickel-tin alloy pipe and a manufacturing method and application thereof. Background Art

[0002] Copper-nickel-tin alloy is widely used in the manufacturing of connecting rod bushings for high-power internal combustion engines because of its advantages such as high strength, hardness, high temperature stability, good wear resistance, higher load-bearing capacity and stronger anti-seizure ability. The connecting rod bushing is a component that connects the piston pin and the connecting rod head of a reciprocating piston engine. Its function is to prevent the piston pin and the connecting rod head from directly contacting and grinding. At the same time, the connecting rod bushing also needs to withstand the alternating load of the piston pin and the inertia force of the connecting rod itself. Therefore, the connecting rod bushing is one of the main vulnerable parts of the engine, and its working reliability and service life will directly affect the working reliability index of the engine.

[0003] A Chinese patent document with publication number CN 109477167 A and publication date March 15, 2019, discloses a method for producing a high-strength copper-nickel-tin alloy strip: continuous casting or semi-continuous casting of strip → annealing of strip → multiple cold rolling of strip → multiple annealing of strip. To further obtain a bushing, the strip must be punched and rolled, and there is a rolling joint.

[0004] The Chinese patent document with publication number CN 117206841 A and publication date December 12, 2023 discloses a method for processing high-strength, high-wear-resistant and corrosion-resistant copper-nickel-tin alloy bars for bushings: copper-tin alloy bar blank → homogenization treatment → car skin → water seal extrusion → primary cold deformation → solution treatment → primary surface cleaning → secondary cold deformation → straightening → cut to length → aging treatment → secondary surface cleaning. The preparation method has a long process flow, and the bar blank must be subjected to 16 to 30 hours of homogenization heat treatment, and multiple cold deformation and surface cleaning are required. To further obtain a bushing, the material preparation method must also punch the bar into 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, the present invention provides a complex copper-nickel-tin alloy pipe and a manufacturing method and application thereof.

[0006] The technical solution provided by the present invention is specifically as follows:

[0007] The first aspect of the present invention provides a complex copper-nickel-tin alloy tube, whose element composition, measured by mass percentage, is: Ni: 5.0% to 10.0%; Sn: 4.0% to 8.0%; Zn: ≤1.0%; Zr: ≤0.2%; Fe: ≤0.1%; Pb: ≤0.1%; Al+Si<0.01%; Re: 0.005% to 0.1%; the rest is copper and unavoidable impurities.

[0008] In combination with the first aspect of the present invention, in some embodiments, the element composition, calculated 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 rest is copper and unavoidable impurities.

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

[0010] In combination 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 spinodal decomposition treatment is 350-400°C.

[0011] In combination with the first aspect of the present invention, in some embodiments, the complex copper-nickel-tin alloy tube has a tensile strength ≥800 MPa, a yield strength ≥650 MPa, a hardness ≥240 HBW, an elongation ≥10%, a matrix structure of a 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 tube, comprising:

[0013] Melting the alloy raw materials to obtain alloy liquid;

[0014] Performing vertical semi-continuous casting or horizontal continuous casting on the alloy liquid to obtain a cast alloy;

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

[0016] The manufacturing method of the complex copper-nickel-tin alloy pipe is mainly semi-continuous casting or horizontal continuous casting ingot, hot extrusion, cold deformation, solution treatment, deep cooling, amplitude modulation decomposition treatment process, directly manufacturing into seamless pipe, with better performance. The pipe can be processed to obtain a bushing with much higher dimensional accuracy than that obtained by rolling.

[0017] In conjunction with the second aspect of the present invention, in some implementation modes:

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

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

[0020] The temperature of the solution treatment is 650-850° C., 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 present invention, in some implementation modes:

[0022] The cryogenic treatment temperature is -180 to -90°C and the time is 1 to 6 hours; and / or,

[0023] The temperature of the spinodal decomposition treatment is 350-400° C. and the time is 3-6 hours.

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

[0025] In combination 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; the cold drawing deformation coefficient is 1.1 to 2.5.

[0026] In combination with the second aspect of the present invention, in some embodiments, a mechanical stirring device is provided on the top of the holding furnace or the intermediate transition ladle, and the rotation speed is set to 30-100 r / min.

[0027] In combination with the second aspect of the present invention, in some embodiments, an electromagnetic device is arranged circumferentially around the crystallizer of 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 80-200A.

[0028] The third aspect of the present invention provides the use of the complex copper-nickel-tin alloy tube in manufacturing 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 the present invention does not have the δ phase, which is a hard and brittle phase. When its content is high, it will affect the plasticity of the alloy, causing the alloy to crack easily during use, reducing the service life of the product and reducing the reliability. The complex copper-nickel-tin alloy pipe manufactured by the present invention has high toughness and is not easy to crack under the subsequent large cold deformation coefficient (cold deformation), and then the strength and elongation are greatly improved through solid solution, deep cryogenic treatment and amplitude modulation decomposition treatment.

[0031] 2. The present invention performs a heat treatment process after the pipe is cut off after cold deformation, thereby solving the limitation of the heat treatment process equipment caused by the pipe being too long after the thermoplastic forming process.

[0032] 3. The heat treatment time of the present invention is short, and the manufacturing cycle of the product is shortened.

[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 procedures due to uneven composition, and reduce manufacturing costs and cycles. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 This is the metallographic structure of the seamless pipe of Example 1 after cold rolling and before solution treatment.

[0036] Figure 2 This is the metallographic structure of the seamless pipe of Example 1 after spinodal decomposition treatment.

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

[0038] Figure 4 This is the metallographic structure of the complex copper-nickel-tin alloy tube obtained in Comparative Example 2. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. 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.

[0040] For simplicity, the present invention only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unambiguous range; and any lower limit can be combined with other lower limits to form an unambiguous range; similarly, any upper limit can be combined with any other upper limit to form an unambiguous range. In addition, although not explicitly stated, each point or single value between the endpoints of the range is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unambiguous range.

[0041] It should be noted that, in the description of the present invention, unless otherwise specified, "above" and "below" are inclusive numbers, and the meaning of "multiple" in "one or more" is two or more. Relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the sentence "including one..." do not exclude the presence of other identical elements in the process, method, article or equipment including the elements.

[0042] In the description of the present invention, the description with reference to the terms "any embodiment / method", "one embodiment / method", "some embodiments / methods", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments / methods or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, without contradiction.

[0043] The above summary of the invention of the present invention is not intended to describe each disclosed embodiment or each implementation in the present invention. The following description more specifically illustrates exemplary embodiments. These embodiments can be used in various combinations. In each example, the enumeration is only used as a representative group and should not be interpreted as exhaustive.

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

[0045] The complex copper-nickel-tin alloy pipe provided by the present invention has the following element compositions by mass percentage: Ni: 5.0% to 10.0%; Sn: 4.0% to 8.0%; Zn: ≤1.0%; Zr: ≤0.2%; Fe: ≤0.1%; Pb: ≤0.1%; Al+Si<0.01%; Re: 0.005% to 0.1%; 其 The rest is copper and unavoidable impurities. The tensile strength of the complex copper-nickel-tin alloy tube is ≥800MPa, the yield strength is ≥650MPa, the hardness is ≥240HBW, the elongation is ≥10%, and the matrix structure is α Phase, grain size 6-8.

[0046] Preferably, the element composition of the complex copper-nickel-tin alloy tube provided by the present invention is, by mass percentage, 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 rest is copper and unavoidable impurities.

[0047] In some embodiments of the present invention, the preparation process of the complex copper-nickel-tin alloy pipe is: casting → hot extrusion → cold deformation → solution treatment → cryogenic treatment → spinodal 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 2-8h; the quenching medium is isothermal quenching oil or rapid quenching oil; the temperature of the cryogenic treatment is -180--90°C; the time is 1-6h; the temperature of the spinodal decomposition treatment is 350-400°C; the time is 3-6h.

[0048] The present invention adds a rare earth element Re to a complex copper-nickel-tin alloy pipe. On the one hand, the rare earth element has a small solid solubility in copper and is easy to form a high-melting-point compound with other elements, and can become a dispersed heterogeneous nucleation core, thereby playing a metamorphic role in refining grains, reducing columnar crystal areas, and improving ingot structure. On the other hand, the rare earth element is easy to react with oxygen, hydrogen, nitrogen, sulfur, and impurities such as lead and bismuth to form slag, which plays a role in degassing, removing impurities, and purifying the melt, thereby improving the mechanical properties and wear resistance of the complex copper-nickel-tin alloy pipe and its products.

[0049] The complex copper-nickel-tin alloy pipe of the present invention strictly controls the Al and Si contents, and adds a proper amount of Zn to improve the fluidity of the alloy liquid while reducing the reverse segregation of the tin bronze, inhibiting the generation of the β phase, and facilitating cold deformation at room temperature.

[0050] Adding a small amount of Zr and Fe elements to the complex copper-nickel-tin alloy tube of the present invention can reduce the grain growth rate, inhibit crystal cell nucleation and growth, shorten the spinodal decomposition strengthening time, and enhance the precipitation strengthening effect.

[0051] The complex copper-nickel-tin alloy pipe of the present invention has sufficient hardness, strength, wear resistance and other properties, can withstand certain impacts, and has certain toughness.

[0052] Manufacturing method:

[0053] The method for manufacturing a complex copper-nickel-tin alloy tube provided by the present invention comprises:

[0054] Melting the alloy raw materials to obtain alloy liquid;

[0055] Performing vertical semi-continuous casting or horizontal continuous casting on the alloy liquid to obtain a cast alloy;

[0056] The cast alloy is subjected to hot extrusion, cold deformation, solution treatment, cryogenic treatment and spinodal decomposition treatment in sequence to obtain the complex copper-nickel-tin alloy pipe.

[0057] The manufacturing method of the present invention first obtains seamless pipes by hot extrusion; then obtains the required size by cold deformation, and then refines the grains in the matrix by solid solution, eliminates stress and restores plasticity; then further dissolves Ni and Sn into the matrix by deep cryogenic treatment; finally, performs amplitude modulation decomposition, and the material strength is significantly increased. The principle of amplitude modulation decomposition treatment is: after the alloy is solid solution treated, elements such as Ni and Sn are solid dissolved into the copper matrix to form a supersaturated solid solution, which will not spontaneously precipitate during the subsequent cooling process. It needs to be heated to a certain temperature to form two solid solutions with the same structure and periodic fluctuations in composition through uphill diffusion of solute atoms. It does not go through a nucleation stage, does not appear another crystal structure, and does not have an obvious phase interface. The solid-state phase transition of the new phase is directly grown by the fluctuation of the composition. The two phases cannot be distinguished optically, and the metallographic structure will not change, which is reflected in the change of hardness.

[0058] The present invention directly forms a seamless pipe by a one-time hot extrusion process. After the cast alloy structure is treated with hot extrusion, cold deformation, solid solution, deep cooling and spinodal decomposition, the grain size is 6 to 8, there is no continuous or discontinuous hard and brittle phase δ phase in the metallographic structure, elements such as Sn and Ni are diffused into the α phase solid solution, and the strength and elongation are greatly improved through spinodal decomposition treatment.

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

[0060] In addition, the present invention optimizes the process flow during the forming process, and optimizes process parameters such as the hot extrusion speed, the hot extrusion ratio, and the cold rolling deformation amount, to ensure that the pipe does not produce defects such as cracks after a cold rolling process, and there is no need to perform multiple cold rolling processes. At the same time, the pipe is longer after hot deformation. The present invention performs a heat treatment process after cold deformation and cutting of the pipe, thereby overcoming the limitation that the heat treatment process equipment cannot process longer pipes.

[0061] In order to solve the problem of alloy liquid homogenization, the patent of the present invention introduces mechanical stirring and electromagnetic stirring technology in the casting process. Under the dual effects of electromagnetic stirring and mechanical stirring, the distribution of easily segregated Sn elements in the alloy liquid is improved to make it fully homogenized, while refining the grains to obtain high-quality cast alloy ingots or tubes, thus eliminating the long-term homogenization heat treatment process required after conventional casting of such alloys and greatly shortening the manufacturing cycle.

[0062] In some embodiments of the present invention, the temperature of hot extrusion is 850-980°C; and / or, the temperature of cold rolling is room temperature; and / or, the temperature of cold drawing is room temperature; and / or, the temperature of solution treatment is 650-850°C; the temperature of deep cryogenic treatment is -180--90°C; the temperature of spinodal 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 function to perform vertical semi-continuous casting or horizontal continuous casting on the alloy liquid to obtain a cast alloy.

[0064] In some embodiments of the present invention, a mechanical stirring device is provided on the top of the holding furnace or the intermediate transition ladle, and the rotation speed is set to 30-100 r / min.

[0065] In some embodiments of the present invention, the vertical semi-continuous casting or horizontal continuous casting crystallizer 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 80-200A.

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

[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 spinodal decomposition treatment time is 3 to 6 hours.

[0070] In some embodiments of the present invention, smelting the alloy raw material includes: melting the alloy raw material, heating the alloy liquid while stirring until it boils, and then adding a refining agent to remove slag. Specifically: after all the alloy raw materials are melted, the medium frequency furnace is fully utilized for electromagnetic stirring to heat and boil for 2 to 3 minutes, and a special refining agent DCQT-X2 is added in an amount of 0.5wt% of the copper liquid, and the slag is removed after standing for 3 to 5 minutes.

[0071] application:

[0072] As described above, the above-mentioned complex copper-nickel-tin alloy pipe can be manufactured into a seamless pipe by the above-mentioned method. The seamless pipe has high strength, high yield, high hardness, high wear resistance, good impact toughness and high temperature oil vapor corrosion resistance, and is suitable for manufacturing connecting rod bushings, for example, heavy-duty automobile connecting rod bushings.

[0073] At present, the main manufacturing process of connecting rod bushings abroad is generally continuous casting or semi-continuous casting of sheet materials. To further obtain bushings, the material preparation method must punch and cut the sheet strip and roll it into shape, and there are rolling joints. The manufacturing process of the connecting rod bushing disclosed in the present invention mainly includes semi-continuous casting or horizontal continuous casting ingots, hot extrusion, cold deformation, solid solution treatment, cryogenic treatment, amplitude modulation decomposition treatment process, and directly manufactures seamless pipes with better performance. The pipe can be processed to obtain a bushing with a dimensional accuracy far higher than that obtained by rolling.

[0074] The technical scheme of the present invention is described in detail below by way of examples. If the manufacturer's brand or manufacturing method is not specified, the raw materials, equipment or solvents used are all common raw materials, equipment or solvents on the market. Unless otherwise specified, the raw materials of the same name used in the following examples and comparative examples are all the same raw materials.

[0075] Among the raw materials used in the following examples and comparative examples, the Cu purity of the copper material is 99.9%, the raw material of Ni is nickel alone, the raw material of Sn is tin alone, and the rare earth material is a rare earth copper alloy.

[0076] Embodiment 1:

[0077] The method for manufacturing the complex copper-nickel-tin alloy tube provided in this embodiment comprises:

[0078] (1) Casting: According to the chemical composition shown in Table 1, first heat and melt a copper material with a Cu purity of 99.9% to form a 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 a rare earth copper alloy. After it is completely melted, add a tin bronze DCQT-X2 refining and slag removal agent in an amount of 0.5wt% of the copper liquid, stir and remove the slag to obtain an alloy liquid; transfer the alloy liquid to an intermediate transition bag, and vigorously stir the alloy liquid under the action of a mechanical stirring motor, and set the speed to 40r / min; perform vertical semi-continuous casting, the alloy liquid enters a crystallizer, and after the bottom is solidified and formed, turn on the specially installed electromagnetic stirrer function, the electromagnetic stirring frequency is 15Hz, the electromagnetic stirring current is 148A, and the casting speed is 4.5m / h to obtain a cast alloy ingot.

[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 set to 25 for hot extrusion to obtain a seamless tube.

[0080] (3) Cold rolling: The seamless pipe is cold rolled at room temperature, and the cold rolling deformation coefficient is 1.85.

[0081] (4) Solution treatment: The cold rolled seamless pipe is subjected to solution treatment at a temperature of 800 °C, a holding time of 2 h, and an isothermal quenching oil as the quenching medium.

[0082] (5) Cryogenic treatment: temperature: -100°C, holding time: 3h.

[0083] (6) Amplitude modulation decomposition treatment: heating temperature: 370°C, holding time: 4 h, to obtain a complex copper-nickel-tin alloy tube.

[0084] Embodiment 2:

[0085] The method for manufacturing the complex copper-nickel-tin alloy tube provided in this embodiment comprises:

[0086] (1) Casting: According to the chemical composition shown in Table 1, a copper material with a Cu purity of 99.9% is first heated and melted to form a 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 is added, and finally a rare earth copper alloy is added. After it is completely melted, a tin bronze DCQT-X2 refining and slag removal agent is added, and the added amount is 0.5wt% of the copper liquid. The slag is removed by stirring to obtain an alloy liquid; the alloy liquid is transferred to an intermediate transition bag, and the alloy liquid is strongly stirred under the action of a mechanical stirring motor, and the speed is set to 30r / min; horizontal continuous casting is performed, and the alloy liquid enters a crystallizer. After the bottom is solidified and formed, a specially installed electromagnetic stirrer function is turned on, and the electromagnetic stirring frequency is 15Hz, the electromagnetic stirring current is 152A, and the casting speed is 3.5m / h to obtain a cast alloy ingot.

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

[0088] (3) Cold rolling: The seamless pipe is cold rolled at room temperature, and the cold rolling deformation coefficient is 1.85.

[0089] (4) Solution treatment: The cold rolled seamless pipe is subjected to solution treatment at a temperature of 750°C, a holding time of 2.5 h, and an isothermal quenching oil as the quenching medium.

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

[0091] (6) Amplitude modulation decomposition treatment: heating temperature: 380°C, holding time: 4 h, to obtain a complex copper-nickel-tin alloy tube.

[0092] Embodiment 3:

[0093] The method for manufacturing the complex copper-nickel-tin alloy tube provided in this embodiment comprises:

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

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

[0096] (3) Cold drawing: The seamless pipe is cold drawn at room temperature, and the cold drawing deformation coefficient is 1.35.

[0097] (4) Solution treatment: The cold rolled seamless pipe is subjected to solution treatment at a temperature of 720°C, a holding time of 3.5 h, and a quenching medium of rapid quenching oil.

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

[0099] (6) Amplitude modulation decomposition treatment: heating temperature: 360°C, holding time: 4.5 h, to obtain a complex copper-nickel-tin alloy tube.

[0100] Embodiment 4:

[0101] The method for manufacturing the complex copper-nickel-tin alloy tube provided in this embodiment comprises:

[0102] (1) Casting: First, heat and melt a copper material with a Cu purity of 99.9% to form a 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 a rare earth copper alloy. After it is completely melted, add a tin bronze DCQT-X2 refining and slag removal agent in an amount of 0.5wt% of the copper liquid, stir and remove the slag to obtain an alloy liquid; transfer the alloy liquid to an intermediate transition bag, and vigorously stir the alloy liquid under the action of a mechanical stirring motor, and set the speed to 38r / min; perform horizontal continuous casting, the alloy liquid enters a crystallizer, and after the bottom is solidified and formed, turn on the specially installed electromagnetic stirrer function, the electromagnetic stirring frequency is 18Hz, the electromagnetic stirring current is 156A, and the casting speed is 4.8m / h to obtain a cast alloy ingot.

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

[0104] (3) Cold drawing: The seamless pipe is cold drawn at room temperature, and the cold drawing deformation coefficient is 1.13.

[0105] (4) Solution treatment: The cold rolled seamless pipe is subjected to solution treatment at a temperature of 680°C, a holding time of 6 hours, and a quenching medium of rapid quenching oil.

[0106] (5) Cryogenic treatment: temperature: -140°C, holding time: 1.5 h.

[0107] (6) Amplitude modulation decomposition treatment: heating temperature: 375°C, holding time: 4.5 h, to obtain a complex copper-nickel-tin alloy tube.

[0108] Comparative Example 1

[0109] Compared with Example 1, this comparative example does not have mechanical stirring and electromagnetic stirring during the casting process, and the specific method of manufacturing the complex copper-nickel-tin alloy pipe provided is as follows:

[0110] (1) Casting: According to the chemical composition of Example 1, a copper material with a Cu purity of 99.9% is first heated and melted to form a copper liquid; then nickel is added in batches; after the nickel is completely melted, a small amount of other alloys such as tin is added, and finally a rare earth copper alloy is added. After the nickel is completely melted, a tin bronze DCQT-X2 refining and slag removal agent is added in an amount of 0.5wt% of the copper liquid, and the slag is removed by stirring to obtain an alloy liquid; the alloy liquid is transferred to an intermediate transition bag for vertical semi-continuous casting at a casting speed of 4.5m / h to obtain a 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 set to 25 for hot extrusion to obtain a seamless tube.

[0112] (3) Cold rolling: The seamless pipe is cold rolled at room temperature, and the cold rolling deformation coefficient is 1.85.

[0113] (4) Solution treatment: The cold rolled seamless pipe is subjected to solution treatment at a temperature of 800 °C, a holding time of 2 h, and an isothermal quenching oil as the quenching medium.

[0114] (5) Cryogenic treatment: temperature: -100°C, holding time: 3h.

[0115] (6) Amplitude modulation decomposition treatment: heating temperature: 370°C, holding time: 4 h, to obtain a complex copper-nickel-tin alloy tube.

[0116] Comparative Example 2

[0117] Compared with Example 1, the solid solution temperature is increased in this comparative example, and the specific method for manufacturing the complex copper-nickel-tin alloy tube provided is as follows:

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

[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 set to 25 for hot extrusion to obtain a seamless tube.

[0120] (3) Cold rolling: The seamless pipe is cold rolled at room temperature, and the cold rolling deformation coefficient is 1.85.

[0121] (4) Solution treatment: The cold rolled seamless pipe is subjected to solution treatment at a temperature of 860°C, a holding time of 2.5 h, and an isothermal quenching oil as the quenching medium.

[0122] (5) Cryogenic treatment: temperature: -100°C, holding time: 3h.

[0123] (6) Amplitude modulation decomposition treatment: heating temperature: 370°C, holding time: 4 h, to obtain a complex copper-nickel-tin alloy tube.

[0124] The complex copper-nickel-tin alloy pipes manufactured in the above embodiments and comparative examples were subjected to hardness tests under GB / T230.1-2018, HRB test conditions, and mechanical property tests were conducted using the GB / T 228.1-2010 test method under GB / T 228B test conditions. Metallographic structure tests were conducted in accordance with GB / T15749-2008 and YS / T 449-2002. Point contact cyclic reciprocating friction and wear testers and rotary friction PV testers were used. The friction and wear test conditions were as follows: normal force: 200N, ambient temperature: 150°C ± 2°C, oscillation frequency: 10Hz, stroke length: 10mm, lubrication: 80W-90GL4, test time: 33min20s (sliding distance 400m), and the wear scar depth of the sample was measured using a three-dimensional profiler. The specific test results are shown in the following table:

[0125] Table 1 Chemical composition

[0126]

[0127]

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

[0129]

[0130] As shown in Table 2, the complex copper-nickel-tin alloy pipes prepared in Examples 1 to 4 of the present invention have 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] The high PV value of the material represents good sintering resistance, indicating that it can still maintain good mechanical sealing under high pressure and high speed conditions.

[0132] Figure 1This is the metallographic structure of the seamless pipe in Example 1 after cold rolling and before solution treatment. The matrix structure is α phase, the black is α+δ phase, and the structure tends to be more brittle.

[0133] Figure 2 The metallographic structure of the seamless pipe of Example 1 after spinodal decomposition is α phase, δ phase is not included, the grain size is 7.5, and there is no obvious segregation in the matrix structure. The seamless pipe has good toughness, is not easy to crack during use, has good product reliability and long service life.

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

[0135] Figure 4 This is the metallographic structure of the complex copper-nickel-tin alloy tube obtained in Comparative Example 2. The grains in the matrix structure have grown significantly, and a large number of black patchy eutectoid phases have appeared, indicating that increasing the solution temperature to 860°C will lead to abnormal growth of the alloy grains.

[0136] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be 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 present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A complex copper-nickel-tin alloy tube, characterized in that: In terms of mass percentage, the element composition is: Ni: 5.0% to 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 rest is copper and inevitable impurities.

2. The complex copper-nickel-tin alloy tube according to claim 1, characterized in that: In terms of mass percentage, the element composition is: The element composition is: Ni: 5.0% to 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 rest are copper and unavoidable impurities.

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

4. The method for manufacturing a complex copper-nickel-tin alloy tube according to claim 3, characterized in that: A mechanical stirring device is installed on the top of the holding furnace or the intermediate transition bag, and the speed is set to 30-100r / min.

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

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

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

5.

8. The method for manufacturing a complex copper-nickel-tin alloy tube according to claim 3, characterized in that: 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; and / or, The cryogenic treatment temperature is -180 to -90°C and the time is 1 to 6 hours; and / or, The temperature of the spinodal decomposition treatment is 350-400° C. and the time is 3-6 hours.

9. Use of the complex copper-nickel-tin alloy tube according to claim 1 or 2 in the manufacture of tubular wear-resistant parts.

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