Preparation process and application of Cu-Ni-Sn alloy

Abstract

The invention belongs to the technical field of alloy material preparation and processing, and particularly relates to a Cu-Ni-Sn system alloy preparation process and application thereof. According to the preparation technology, recrystallization heat treatment and small-deformation secondary cold rolling processes are introduced in the alloy machining process, on one hand, the recrystallization heat treatment process greatly reduces the grain size of a material and enables element distribution to be more uniform, the comprehensive mechanical property of the recrystallization-state Cu-15Ni-8Sn alloy is obviously improved, the tensile strength of the alloy is 490 MPa, and the mechanical property of the alloy is improved; the percentage elongation after fracture can reach 65%; and on the other hand, secondary cold rolling with small deformation (the deformation is smaller than 45%) is carried out on the basis of a recrystallized-state material, the plasticity loss caused by deformation is reduced by reducing the deformation strengthening effect, the strength can be guaranteed, and good plasticity is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of alloy material preparation and processing, and specifically relates to a preparation process and application of a Cu-Ni-Sn alloy. Background Art

[0002] High-strength elastic copper alloys can be used to produce springs, connectors, bearings, bushings and other parts due to their high strength, wear resistance, fatigue resistance and other characteristics. They are widely used in the electronics industry, precision instruments, aerospace, marine engineering and other fields. Beryllium copper is a traditional high-strength and high-elastic copper alloy material with excellent mechanical properties and occupies a large market size. However, the preparation and processing of beryllium copper is prone to produce toxic dust, which pollutes the environment; the performance stability deteriorates above 150°C, and the ability to resist stress relaxation is low; the expensive beryllium element leads to high production costs. Cu-Ni-Sn alloy is an aging-strengthened and work-hardened copper alloy with a tensile strength comparable to that of beryllium copper. It also has excellent load-bearing performance, stress relaxation resistance and corrosion resistance, and has great potential in replacing beryllium copper alloys.

[0003] At present, the conventional preparation and processing technology of high-strength Cu-Ni-Sn alloys is: homogenization / solid solution + large deformation cold working + isothermal aging. After conventional processing, the alloy grain structure is coarse, the dislocation density is high but unevenly distributed, the precipitated phase is also unevenly distributed due to the influence of dislocations, and the elements are not completely evenly distributed. Although the alloy can obtain high strength, the plasticity of the material is very poor. For example, the C72900 (Cu-15Ni-8Sn) alloy with excellent mechanical properties in the Cu-Ni-Sn alloy can reach a tensile strength of 1100-1200MPa after conventional processing, but the elongation after fracture is less than 3%. While ensuring the high strength of the alloy, improving the plasticity of the alloy becomes the key. Cu-Ni-Sn alloy is a highly segregated alloy. In conventional processes, it is difficult to make the elements completely evenly distributed by a single solution treatment. In order to eliminate component segregation, the prior art uses a casting method to prepare a Cu-6Ni-6Sn alloy, which is kept at 830°C for 24 hours for homogenization treatment, and then hot forging + hot rolling + multiple solution and cold rolling treatments are performed. After the treatment, the elements are evenly distributed. In order to improve the mechanical properties of Cu-Ni-Sn alloys, some researchers have improved the comprehensive mechanical properties of materials by optimizing the processing technology. There are also researchers who have treated the Cu-15Ni-8Sn alloy by homogenization annealing + hot extrusion + double-stage aging. The tensile strength of the material is 1013MPa and the elongation after fracture is 8.3%. There is also a processing technology of hot forging + homogenization + cold rolling + solution + cold rolling + aging to treat the Cu-15Ni-8Sn alloy. The tensile strength of the material reaches ~1100MPa and the elongation after fracture is ~7%. Some researchers have also improved the performance of materials by microalloying and combining related processing techniques. Some have also prepared Cu-15Ni-8Sn alloys by adding microalloying elements such as Mn, Si, Nb, Cr, and Zr, and processed the materials through homogenization + hot rolling + cold deformation + multi-stage aging process. The tensile strength of the material can reach 1200MPa and the elongation after fracture is about 3.5%. And on the basis of Cu-15Ni-8Sn alloy, microalloying elements such as Zn, Si, Al, Mn, Ce, and Y are added, and homogenization + hot extrusion + solid solution + cold drawing deformation + aging treatment is performed on it. After treatment, the tensile strength of the alloy exceeds 1150MPa and the elongation after fracture is 4% to 5%. Although the strength and plasticity of the material can be improved by combining microalloying with some processing techniques, the improvement is small, and the strength and plasticity of the material are still within the same order of magnitude. Some of the new process combinations currently proposed make the processing flow of Cu-Ni-Sn alloys more complicated and the processing cost higher, which undoubtedly limits the applicability of these processes. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the comprehensive mechanical properties of Cu-Ni-Sn alloys are low after conventional process treatment, and to provide a new preparation and processing technology to improve the comprehensive mechanical properties of Cu-Ni-Sn alloys, so that the material can not only ensure ultra-high strength, but also have high plasticity. The traditional conventional process is due to the serious segregation of the cast structure of Cu-Ni-Sn alloys, the high homogenization and solid solution temperatures, and the long time used, resulting in a large grain size of the solid solution material, and it is difficult to make the elements completely uniformly distributed in a single solid solution process. Taking Cu-15Ni-8Sn alloy as an example, the mechanical properties of the solid solution Cu-15Ni-8Sn alloy are low, and its tensile strength is ~340MPa and its elongation after fracture is ~35%. At the same time, the conventional process often uses large deformation processing (deformation amount>90%) combined with aging treatment to improve the material strength after solid solution treatment, resulting in increased material strength and very low plasticity (<3%). The present invention changes the conventional process and introduces a recrystallization heat treatment and a small deformation secondary cold rolling process in the alloy processing process. On the one hand, the recrystallization heat treatment process greatly reduces the grain size of the material and makes the element distribution more uniform, and the comprehensive mechanical properties of the recrystallized Cu-15Ni-8Sn alloy are significantly improved, and its tensile strength is 490MPa and the elongation after fracture can reach 65%. On the other hand, secondary cold rolling with a small deformation amount (deformation amount <45%) is performed on the basis of the recrystallized material, and the deformation strengthening effect is reduced to reduce the plastic loss caused by the deformation, so as to achieve the purpose of both ensuring strength and having good plasticity.

[0005] The invention has a simple processing flow, low processing cost, is conducive to engineering application, and is applicable to all aging-strengthened Cu-Ni-Sn alloys. The comprehensive mechanical properties of the Cu-Ni-Sn alloys treated by the novel preparation and processing technology provided by the invention are significantly improved, making the material safer and more reliable during service.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme: a preparation process of a Cu-Ni-Sn alloy, the preparation process specifically comprising the following steps:

[0007] S1) preparing a Cu-Ni-Sn alloy ingot, and subjecting the Cu-Ni-Sn alloy ingot to a homogenizing solid solution treatment and water quenching;

[0008] S2) cold rolling the Cu-Ni-Sn alloy ingot treated by S1);

[0009] S3) performing a crystallization heat treatment on the Cu-Ni-Sn alloy ingot treated in S2);

[0010] S4) performing secondary cold rolling on the Cu-Ni-Sn alloy ingot treated in S3);

[0011] S5) performing a temperature-raising aging treatment on the Cu-Ni-Sn alloy ingot treated in S4) to obtain a high-performance Cu-Ni-Sn alloy. (The order of steps in the preparation process of the present invention cannot be reversed at will)

[0012] Furthermore, the Cu-Ni-Sn alloy includes: pure component Cu-Ni-Sn alloy and Cu-Ni-Sn-X alloy with added micro-alloy elements (wherein 5wt.%≤Ni≤19wt.%, 5wt.%≤Sn≤10wt.%).

[0013] Furthermore, the homogenization solution temperature in S1) is 600-1000° C., and the holding time is 2-12 hours.

[0014] Furthermore, the cold rolling deformation in S2) is 70% to 95%.

[0015] Furthermore, the recrystallization temperature in S3) is 600-1000° C., and the holding time of the recrystallization process is 3-8 minutes.

[0016] Furthermore, the secondary cold rolling deformation in S4) is not more than 45%.

[0017] Furthermore, the deformation amount of the secondary cold rolling in S4) is 20-44%.

[0018] Furthermore, the temperature of the heating aging treatment in S5) is 250-550°C, the heating rate is 3-15°C / min, and the temperature is kept for 0.25-4h.

[0019] Furthermore, the tensile strength of the Cu-Ni-Sn alloy obtained by the preparation process is not less than 700 MPa, the yield strength is not less than 600 MPa, the elongation is not less than 8%, and the strength-ductility product is not less than 9000 MPa%.

[0020] The Cu-Ni-Sn alloy prepared by the above-mentioned preparation process is used in the production of connectors, bearings, bushings and precision instrument parts, such as relays, potentiometers, switch contact springs, etc.

[0021] Compared with the conventional preparation of Cu-Ni-Sn alloy and some currently proposed processing techniques, the advantages of the present invention are as follows:

[0022] (1) Although the strength of Cu-Ni-Sn alloys is high after conventional processing, their plasticity is very poor. Some processing technologies currently proposed can further improve the comprehensive mechanical properties of Cu-Ni-Sn alloys, but the improvement effect is not obvious, and the processing flow is too complicated, which is not conducive to actual production applications. The new preparation and processing technology provided by the present invention can significantly improve the comprehensive mechanical properties of the material, and the process flow is relatively simpler.

[0023] (2) The current method to improve the mechanical properties of Cu-Ni-Sn alloys usually adopts microalloying combined with some optimized processing technology, but this makes the material cost and processing cost higher. This paper can make pure Cu-Ni-Sn alloy obtain higher strength and good plasticity by simply improving the processing technology, saving material costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a flowchart of a preparation process of a Cu-Ni-Sn alloy. DETAILED DESCRIPTION

[0025] The specific embodiments of the present invention are further described in detail below, but the present invention is not limited to these embodiments.

[0026] like Figure 1 As shown, the present invention provides a preparation process of a Cu-Ni-Sn alloy, and the preparation process specifically comprises the following steps:

[0027] The casting is subjected to homogenization solution treatment, cold rolling, recrystallization, secondary cold rolling and aging treatment in sequence. The specific steps and process parameters are as follows:

[0028] Step 1: Homogenization and solid solution

[0029] (1) First, a high-frequency induction melting furnace is used to melt metal blocks such as Cu, Ni, and Sn at a heating temperature of 1100 to 1300°C. After each metal is melted, the metal is kept warm for 5 to 15 minutes and then cast into a graphite mold to obtain a Cu-Ni-Sn alloy ingot.

[0030] (2) The cast Cu-Ni-Sn alloy is subjected to homogenization solution treatment, and the heating temperature is determined according to the content of Ni, Sn and the content of micro-alloying elements.

[0031] (3) After homogenization and solid solution, the material is water quenched.

[0032] Step 2: Cold rolling

[0033] The material after homogenization and solution treatment in step 1 is cold rolled.

[0034] Step 3: Recrystallization

[0035] The material after cold rolling in step 2 is subjected to recrystallization heat treatment.

[0036] Step 4: Secondary cold rolling

[0037] The material after recrystallization treatment in step 3 is subjected to secondary cold rolling.

[0038] Step 5: Heating and aging treatment

[0039] The material after the secondary cold rolling in step 4 is subjected to a heating aging treatment, firstly the material is slowly heated from room temperature to a certain temperature, and then isothermally kept at this temperature for a certain period of time.

[0040] In the step 1, the homogenization solution temperature of the Cu-Ni-Sn system alloy is 600-1000° C., and the holding time is 2-12 hours.

[0041] The cold rolling deformation in step 2 is 70% to 95%.

[0042] The recrystallization temperature in step three is 600-1000° C., and the holding time of the recrystallization process is 3-8 minutes.

[0043] The cold rolling deformation in step 4 is 25% to 45%.

[0044] The aging temperature in step five is 250-550° C., the slow heating rate during the heating aging process is 3-15° C. / min, and then the temperature is kept isothermally at 250-550° C. for 0.25-5h.

[0045] In the embodiment, two kinds of Cu-Ni-Sn alloy ingots with higher and lower Ni and Sn contents are used. Taking Cu-6Ni-6Sn, Cu-15Ni-8Sn and Cu-15Ni-8Sn-0.3Si-0.2Ti alloys as examples, their chemical compositions are shown in Table 1:

[0046] Table 1: Chemical composition of Cu-Ni-Sn alloy ingot (wt.%)

[0047]

[0048] Comparative Example 1

[0049] The conventional processing technology of Cu-Ni-Sn alloy includes the following steps and their process parameters:

[0050] Step 1: Homogenization solution treatment

[0051] (1) First, a high-frequency induction melting furnace is used to melt metal blocks such as Cu, Ni, and Sn at a heating temperature of 1250°C. After each metal is melted, the metal is kept warm for 10 minutes and then cast into a graphite mold to obtain a Cu-15Ni-8Sn alloy ingot.

[0052] (2) The as-cast Cu-15Ni-8Sn alloy ingot was subjected to homogenization solution treatment at a heating temperature of 900°C for 4 hours.

[0053] (3) After homogenization and solid solution, the material is water quenched.

[0054] Step 2: Cold rolling

[0055] The material after homogenization and solution treatment in step 1 is cold rolled by 70%.

[0056] Step 3: Aging Process

[0057] After 70% cold rolling, the material was isothermally kept at 400°C for 1 h for aging treatment.

[0058] Comparative Example 2

[0059] The conventional processing technology of Cu-Ni-Sn alloy includes the following steps and their process parameters:

[0060] Step 1: Homogenization solution treatment

[0061] (1) First, a high-frequency induction melting furnace is used to melt metal blocks such as Cu, Ni, and Sn at a heating temperature of 1250°C. After each metal is melted, the metal is kept warm for 10 minutes and then cast into a graphite mold to obtain a Cu-15Ni-8Sn alloy ingot.

[0062] (2) The as-cast Cu-15Ni-8Sn alloy ingot was subjected to homogenization solution treatment at a heating temperature of 900°C for 4 hours.

[0063] (3) After homogenization and solid solution, the material is water quenched.

[0064] Step 2: Cold rolling

[0065] The material after homogenization and solution treatment in step 1 is cold rolled by 90%.

[0066] Step 3: Aging Process

[0067] After 90% cold rolling, the material was isothermally kept at 400°C for 1 h for aging treatment.

[0068] Example 1

[0069] A preparation process of a Cu-Ni-Sn alloy comprises the following steps and process parameters:

[0070] Step 1: Homogenization solution treatment

[0071] (1) First, a high-frequency induction melting furnace is used to melt metal blocks such as Cu, Ni, and Sn at a heating temperature of 1250°C. After each metal is melted, the metal is kept warm for 10 minutes and then cast into a graphite mold to obtain a Cu-15Ni-8Sn alloy ingot.

[0072] (2) The as-cast Cu-15Ni-8Sn alloy ingot was subjected to homogenization solution treatment at a heating temperature of 900°C for 4 hours.

[0073] (3) After homogenization and solid solution, the material is water quenched.

[0074] Step 2: Cold rolling

[0075] The material after homogenization and solution treatment in step 1 is cold rolled by 90%.

[0076] Step 3: Recrystallization

[0077] The material after cold rolling in step 2 is subjected to recrystallization heat treatment, with a heating temperature of 850° C. and a holding time of 3 min.

[0078] Step 4: Secondary cold rolling

[0079] The material after recrystallization treatment in step 3 is subjected to secondary cold rolling with a deformation amount of 30%.

[0080] Step 5: Aging Process

[0081] The material after the secondary cold rolling in step 4 is subjected to a heating aging treatment. First, the material is slowly heated from room temperature to 400°C at a heating rate of 6°C / min, and then is isothermally kept at 400°C for 0.5h.

[0082] Example 2

[0083] A preparation process of a Cu-Ni-Sn alloy comprises the following steps and process parameters:

[0084] Step 1: Homogenization solution treatment

[0085] (1) First, a high-frequency induction melting furnace is used to melt metal blocks such as Cu, Ni, and Sn at a heating temperature of 1250°C. After each metal is melted, the metal is kept warm for 10 minutes and then cast into a graphite mold to obtain a Cu-15Ni-8Sn alloy ingot.

[0086] (2) The as-cast Cu-15Ni-8Sn alloy ingot was subjected to homogenization solution treatment at a heating temperature of 900°C for 4 hours.

[0087] (3) After homogenization and solid solution, the material is water quenched.

[0088] Step 2: Cold rolling

[0089] The material after homogenization and solution treatment in step 1 is cold rolled by 90%.

[0090] Step 3: Recrystallization

[0091] The material after cold rolling in step 2 is subjected to recrystallization heat treatment, with a heating temperature of 850° C. and a holding time of 5 min.

[0092] Step 4: Secondary cold rolling

[0093] The material after recrystallization treatment in step 3 is subjected to secondary cold rolling with a deformation amount of 30%.

[0094] Step 5: Aging Process

[0095] The material after the secondary cold rolling in step 4 is subjected to a heating aging treatment. First, the material is slowly heated from room temperature to 400°C at a heating rate of 6°C / min, and then is isothermally kept at 400°C for 0.5h.

[0096] Embodiment 3:

[0097] A novel preparation process of a Cu-Ni-Sn alloy system comprises the following steps and process parameters:

[0098] Step 1: Homogenization solution treatment

[0099] (1) First, a high-frequency induction melting furnace is used to melt metal blocks such as Cu, Ni, and Sn at a heating temperature of 1250°C. After each metal is melted, the metal is kept warm for 10 minutes and then cast into a graphite mold to obtain a Cu-15Ni-8Sn alloy ingot.

[0100] (2) The as-cast Cu-15Ni-8Sn alloy ingot was subjected to homogenization solution treatment at a heating temperature of 900°C for 4 hours.

[0101] (3) After homogenization and solid solution, the material is water quenched.

[0102] Step 2: Cold rolling

[0103] The material after homogenization and solution treatment in step 1 is cold rolled by 90%.

[0104] Step 3: Recrystallization

[0105] The material after cold rolling in step 2 is subjected to recrystallization heat treatment, with a heating temperature of 850° C. and a holding time of 7 minutes.

[0106] Step 4: Secondary cold rolling

[0107] The material after recrystallization treatment in step 3 is subjected to secondary cold rolling with a deformation amount of 30%.

[0108] Step 5: Aging Process

[0109] The material after the secondary cold rolling in step 4 is subjected to a heating aging treatment. First, the material is slowly heated from room temperature to 400°C at a heating rate of 6°C / min, and then is isothermally kept at 400°C for 0.5h.

[0110] Embodiment 4:

[0111] A preparation process of a Cu-Ni-Sn alloy comprises the following steps and process parameters:

[0112] Step 1: Homogenization solution treatment

[0113] (1) First, a high-frequency induction melting furnace is used to melt metal blocks such as Cu, Ni, and Sn at a heating temperature of 1250°C. After each metal is melted, the metal is kept warm for 10 minutes and then cast into a graphite mold to obtain a Cu-15Ni-8Sn alloy ingot.

[0114] (2) The as-cast Cu-15Ni-8Sn alloy ingot was subjected to homogenization solution treatment at a heating temperature of 900°C for 4 hours.

[0115] (3) After homogenization and solid solution, the material is water quenched.

[0116] Step 2: Cold rolling

[0117] The material after homogenization and solution treatment in step 1 is cold rolled by 90%.

[0118] Step 3: Recrystallization

[0119] The material after cold rolling in step 2 is subjected to recrystallization heat treatment, with a heating temperature of 850° C. and a holding time of 3 min.

[0120] Step 4: Secondary cold rolling

[0121] The material after recrystallization treatment in step 3 is subjected to secondary cold rolling with a deformation amount of 40%.

[0122] Step 5: Aging Process

[0123] The material after the secondary cold rolling in step 4 is subjected to a heating aging treatment. First, the material is slowly heated from room temperature to 400°C at a heating rate of 6°C / min, and then is isothermally kept at 400°C for 0.5h.

[0124] Embodiment 5:

[0125] A new preparation and processing technology that can significantly improve the comprehensive mechanical properties of Cu-Ni-Sn alloys includes the following steps and process parameters:

[0126] Step 1: Homogenization solution treatment

[0127] (1) First, a high-frequency induction melting furnace is used to melt metal blocks such as Cu, Ni, and Sn at a heating temperature of 1250°C. After each metal is melted, the metal is kept warm for 10 minutes and then cast into a graphite mold to obtain a Cu-15Ni-8Sn alloy ingot.

[0128] (2) The as-cast Cu-15Ni-8Sn alloy ingot was subjected to homogenization solution treatment at a heating temperature of 900°C for 4 hours.

[0129] (3) After homogenization and solid solution, the material is water quenched.

[0130] Step 2: Cold rolling

[0131] The material after homogenization and solution treatment in step 1 is cold rolled by 90%.

[0132] Step 3: Recrystallization

[0133] The material after cold rolling in step 2 is subjected to recrystallization heat treatment, with a heating temperature of 850° C. and a holding time of 5 min.

[0134] Step 4: Secondary cold rolling

[0135] The material after recrystallization treatment in step 3 is subjected to secondary cold rolling with a deformation amount of 40%.

[0136] Step 5: Aging Process

[0137] The material after the secondary cold rolling in step 4 is subjected to a heating aging treatment. First, the material is slowly heated from room temperature to 400°C at a heating rate of 6°C / min, and then is isothermally kept at 400°C for 0.5h.

[0138] Comparative Example 3

[0139] The conventional processing technology of Cu-Ni-Sn alloy includes the following steps and their process parameters:

[0140] Step 1: Homogenization solution treatment

[0141] (1) First, a high-frequency induction melting furnace is used to melt metal blocks such as Cu, Ni, and Sn at a heating temperature of 1200°C. After each metal is melted, the mixture is kept warm for 10 minutes and then cast into a graphite mold to obtain a Cu-6Ni-6Sn alloy ingot.

[0142] (2) The as-cast Cu-6Ni-6Sn alloy ingot was subjected to homogenization solution treatment at a heating temperature of 900°C for 3 h.

[0143] (3) After homogenization and solid solution, the material is water quenched.

[0144] Step 2: Cold rolling

[0145] The material after homogenization and solution treatment in step 1 is cold rolled by 70%.

[0146] Step 3: Aging Process

[0147] After 70% cold rolling, the material was isothermally kept at 400°C for 1 h for aging treatment.

[0148] Comparative Example 4

[0149] The conventional processing technology of Cu-Ni-Sn alloy includes the following steps and their process parameters:

[0150] Step 1: Homogenization solution treatment

[0151] (1) First, a high-frequency induction melting furnace is used to melt metal blocks such as Cu, Ni, and Sn at a heating temperature of 1200°C. After each metal is melted, the mixture is kept warm for 10 minutes and then cast into a graphite mold to obtain a Cu-6Ni-6Sn alloy ingot.

[0152] (2) The as-cast Cu-6Ni-6Sn alloy ingot was subjected to homogenization solution treatment at a heating temperature of 900°C for 3 h.

[0153] (3) After homogenization and solid solution, the material is water quenched.

[0154] Step 2: Cold rolling

[0155] The material after homogenization and solution treatment in step 1 is cold rolled by 90%.

[0156] Step 3: Aging Process

[0157] After 90% cold rolling, the material was isothermally kept at 400°C for 1 h for aging treatment.

[0158] Example 6

[0159] A Cu-Ni-Sn alloy preparation process includes the following steps and process parameters:

[0160] Step 1: Homogenization solution treatment

[0161] (1) First, a high-frequency induction melting furnace is used to melt metal blocks such as Cu, Ni, and Sn at a heating temperature of 1200°C. After each metal is melted, the mixture is kept warm for 10 minutes and then cast into a graphite mold to obtain a Cu-6Ni-6Sn alloy ingot.

[0162] (2) The as-cast Cu-6Ni-6Sn alloy ingot was subjected to homogenization solution treatment at a heating temperature of 900°C for 3 h.

[0163] (3) After homogenization and solid solution, the material is water quenched.

[0164] Step 2: Cold rolling

[0165] The material after homogenization and solution treatment in step 1 is cold rolled by 90%.

[0166] Step 3: Recrystallization

[0167] The material after cold rolling in step 2 is subjected to recrystallization heat treatment, with a heating temperature of 850° C. and a holding time of 3 min.

[0168] Step 4: Secondary cold rolling

[0169] The material after recrystallization treatment in step 3 is subjected to secondary cold rolling with a deformation amount of 30%.

[0170] Step 5: Aging Process

[0171] The material after the secondary cold rolling in step 4 is subjected to a heating aging treatment. First, the material is slowly heated from room temperature to 400°C at a heating rate of 6°C / min, and then is isothermally kept at 400°C for 0.5h.

[0172] Example 7

[0173] A preparation process of a Cu-Ni-Sn alloy comprises the following steps and process parameters:

[0174] Step 1: Homogenization solution treatment

[0175] (1) First, a high-frequency induction melting furnace is used to melt metal blocks such as Cu, Ni, and Sn at a heating temperature of 1200°C. After each metal is melted, the mixture is kept warm for 10 minutes and then cast into a graphite mold to obtain a Cu-6Ni-6Sn alloy ingot.

[0176] (2) The as-cast Cu-6Ni-6Sn alloy ingot was subjected to homogenization solution treatment at a heating temperature of 900°C for 3 h.

[0177] (3) After homogenization and solid solution, the material is water quenched.

[0178] Step 2: Cold rolling

[0179] The material after homogenization and solution treatment in step 1 is cold rolled by 90%.

[0180] Step 3: Recrystallization

[0181] The material after cold rolling in step 2 is subjected to recrystallization heat treatment, with a heating temperature of 850° C. and a holding time of 5 min.

[0182] Step 4: Secondary cold rolling

[0183] The material after recrystallization treatment in step 3 is subjected to secondary cold rolling with a deformation amount of 40%.

[0184] Step 5: Aging Process

[0185] The material after the secondary cold rolling in step 4 is subjected to a heating aging treatment. First, the material is slowly heated from room temperature to 400°C at a heating rate of 6°C / min, and then is isothermally kept at 400°C for 0.5h.

[0186] Comparative Example 5

[0187] The conventional processing technology of Cu-Ni-Sn alloy includes the following steps and their process parameters:

[0188] Step 1: Homogenization solution treatment

[0189] (1) First, a high-frequency induction melting furnace was used to melt bulk materials such as Cu, Ni, Sn, Si, and Ti at a heating temperature of 1250°C. After each metal was melted, the mixture was kept warm for 10 min and then cast into a graphite mold to obtain a Cu-15Ni-8Sn-0.3Si-0.2Ti alloy ingot.

[0190] (2) The as-cast Cu-15Ni-8Sn-0.3Si-0.2Ti alloy ingot was subjected to homogenization solution treatment at a heating temperature of 900°C for 7 hours.

[0191] (3) After homogenization and solid solution, the material is water quenched.

[0192] Step 2: Cold rolling

[0193] The material after homogenization and solution treatment in step 1 is cold rolled by 90%.

[0194] Step 3: Aging Process

[0195] After 90% cold rolling, the material was isothermally kept at 400°C for 1 h for aging treatment.

[0196] Example 8

[0197] A preparation process of a Cu-Ni-Sn alloy comprises the following steps and process parameters:

[0198] Step 1: Homogenization solution treatment

[0199] (1) First, a high-frequency induction melting furnace was used to melt bulk materials such as Cu, Ni, Sn, Si, and Ti at a heating temperature of 1250°C. After each metal was melted, the mixture was kept warm for 10 min and then cast into a graphite mold to obtain a Cu-15Ni-8Sn-0.3Si-0.2Ti alloy ingot.

[0200] (2) The as-cast Cu-15Ni-8Sn-0.3Si-0.2Ti alloy ingot was subjected to homogenization solution treatment at a heating temperature of 900°C for 7 hours.

[0201] (3) After homogenization and solid solution, the material is water quenched.

[0202] Step 2: Cold rolling

[0203] The material after homogenization and solution treatment in step 1 is cold rolled by 90%.

[0204] Step 3: Recrystallization

[0205] The material after cold rolling in step 2 is subjected to recrystallization heat treatment, with a heating temperature of 850° C. and a holding time of 5 min.

[0206] Step 4: Secondary cold rolling

[0207] The material after recrystallization treatment in step 3 is subjected to secondary cold rolling with a deformation amount of 30%.

[0208] Step 5: Aging Process

[0209] The material after the secondary cold rolling in step 4 is subjected to a heating aging treatment. First, the material is slowly heated from room temperature to 400°C at a heating rate of 6°C / min, and then is isothermally kept at 400°C for 0.5h.

[0210] The tensile properties of each embodiment are shown in Table 2:

[0211] Table 2: Tensile performance test values ​​of various examples

[0212]

[0213] It can be seen from Table 2 that after the same material is treated by conventional process and novel heat treatment process, the comprehensive mechanical properties of the material are greatly different. After the novel preparation process, the comprehensive mechanical properties of the material are significantly improved. The Cu-Ni-Sn system alloy treated by the novel heat treatment process introduced in the present invention has excellent comprehensive mechanical properties.

[0214] The above embodiments do not limit the present invention in any way. The present invention is applicable to all aging-hardened and work-hardened pure component Cu-Ni-Sn alloys and Cu-Ni-Sn alloys with added micro-alloy elements. All technical methods obtained by equivalent replacement or equivalent replacement fall within the protection scope of the present invention.

Claims

1. A process for preparing a Cu-Ni-Sn alloy, characterized in that: The preparation process specifically comprises the following steps: S1) preparing a Cu-Ni-Sn alloy ingot and subjecting the Cu-Ni-Sn alloy ingot to a homogenizing solid solution treatment and water quenching; S2) cold rolling the Cu-Ni-Sn alloy ingot treated by S1); S3) performing a crystallization heat treatment on the Cu-Ni-Sn alloy ingot treated in S2); S4) performing secondary cold rolling on the Cu-Ni-Sn alloy ingot treated in S3); S5) performing a temperature-raising aging treatment on the Cu-Ni-Sn alloy ingot treated in S4) to obtain a high-performance Cu-Ni-Sn alloy.

2. The preparation process according to claim 1, characterized in that: The Cu-Ni-Sn alloy system includes: a pure component Cu-Ni-Sn alloy and a Cu-Ni-Sn-X alloy system with added micro-alloy elements.

3. The preparation process according to claim 1, characterized in that: The homogenization solution temperature in S1) is 600-1000°C, and the holding time is 2-12h.

4. The preparation process according to claim 1, characterized in that: The cold rolling deformation in S2) is 70% to 95%.

5. The preparation process according to claim 1, characterized in that: The recrystallization temperature in S3) is 600-1000°C, and the holding time of the recrystallization process is 3-8 minutes.

6. The preparation process according to claim 1, characterized in that: The secondary cold rolling deformation in S4) is not more than 45%.

7. The preparation process according to claim 1, characterized in that: The secondary cold rolling deformation in S4) is 20-44%.

8. The preparation process according to claim 1, characterized in that: The temperature of the heating aging treatment in S5) is 250-550°C, the heating rate is 3-15°C / min, and the insulation time is 0.25-4h.

9. The preparation process according to claim 1, characterized in that: The tensile strength of the Cu-Ni-Sn alloy obtained by the preparation process is not less than 700 MPa, the yield strength is not less than 600 MPa, the elongation is not less than 8%, and the strength-ductility product is not less than 9000 MPa%.

10. A Cu-Ni-Sn alloy prepared by the preparation process according to any one of claims 1 to 9 is used in the manufacturing field of connectors, bearings, bushings and precision instrument parts.

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