Large-size high-tin copper alloy cast ingot with high plasticity and excellent cold rolling performance and preparation method of large-size high-tin copper alloy cast ingot

Abstract

The invention discloses a large-size high-tin copper alloy cast ingot with high plasticity and excellent cold rolling performance and a preparation method of the large-size high-tin copper alloy cast ingot, and belongs to the technical field of alloy materials. The high-tin copper alloy is smelted and then subjected to rapid chilling treatment and homogenization treatment, high-quality semi-solid metal slurry is prepared, then the high-quality semi-solid metal slurry is injected into a mold, secondary chilling and extrusion are carried out, the secondary chilling nucleation technology of the mold wall is utilized, dendrites in the structure are further prevented from being generated, and the high-tin copper alloy is obtained. The structure and mechanical properties of the alloy cast ingot are improved, and finally the large-size high-tin copper alloy cast ingot with high plasticity and excellent cold rolling performance is obtained. According to the preparation method provided by the invention, the brittle delta phase in the alloy is thoroughly eliminated, the step of subsequent high-temperature long-time heat treatment is omitted, short process and low cost are realized, the production efficiency is improved, and the purposes of energy conservation and emission reduction are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of alloy materials, and in particular relates to a large-size high-tin copper alloy ingot with high plasticity and excellent cold rolling performance and a preparation method thereof. Background Art

[0002] High-tin copper alloys are widely used in high-speed rail, shipbuilding, aviation and other fields due to their excellent mechanical properties. However, the direct production of large-diameter, high-plasticity high-tin copper alloy ingots without brittle δ phase using a casting process faces many challenges, mainly reflected in the following aspects: 1. Formation of brittle δ phase: In copper-tin alloys, when the tin content reaches or exceeds 10wt.%, brittle δ phase is easily formed. This brittle phase becomes the source of crack initiation and expansion during plastic deformation, resulting in the material being unusable in subsequent processing and strengthening processes such as rolling, forging and drawing. 2. Limitations of the forming process: The current high-plasticity high-tin copper alloy ingot forming process mostly adopts a casting combined with annealing treatment method. Although homogenization treatment can eliminate the brittle δ phase, it will also lead to an increase in the grain size of the alloy. In addition, high-temperature and long-term annealing significantly increases production energy consumption and time, resulting in the traditional method having complex process flow, long production cycle, high cost and coarse ingot structure.

[0003] At present, there is no research report on directly obtaining large-sized, brittle δ-phase-free high-tin copper alloy ingots with high plasticity and excellent cold rolling performance by casting. Therefore, it is urgent to develop a production method for large-diameter high-tin copper alloy ingots with high plasticity and excellent cold rolling performance, short process flow, short production cycle and low cost, so as to meet the needs of defense, military industry, aerospace and other fields for high-strength, high-plasticity large-diameter high-tin copper alloy ingots. Summary of the invention

[0004] In order to solve the above technical problems, the present invention proposes a large-size high-tin copper alloy ingot with high plasticity and excellent cold rolling performance and a preparation method thereof.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing a large-sized high-tin copper alloy ingot having both high plasticity and excellent cold rolling performance, comprising the following steps:

[0007] (1) melting a high-tin copper alloy and then rapidly quenching the alloy to obtain a semi-solid metal slurry;

[0008] (2) homogenizing the semi-solid metal slurry obtained in step (1) to obtain high-quality semi-solid metal slurry;

[0009] (3) The high-quality semi-solid metal slurry obtained in step (2) is injected into a mold, and after secondary quenching and extrusion, a large-sized high-tin copper alloy ingot with high plasticity and excellent cold rolling performance is obtained.

[0010] The present invention prepares semi-solid metal slurry by rapid quenching treatment. On the one hand, the rapid quenching treatment causes a large number of crystal nuclei to be generated when the high-tin copper alloy liquid solidifies; on the other hand, the fast-flowing metal liquid effectively breaks the dendrites in the growth process, thereby significantly increasing the number of crystal nuclei in the melt during the solidification process, and effectively inhibiting the mutual annexation and growth of the crystal nuclei. This process refines the grains, significantly reduces the quality defects such as cracks, shrinkage cavities, shrinkage porosity and pores of the high-tin copper alloy ingot, and enables the material to not crack during large plastic cold rolling deformation. Then, the high-quality semi-solid metal slurry is injected into the mold, and after secondary quenching and extrusion, the secondary quenching nucleation process technology of the mold wall is used to further prevent the generation of dendrites in the organization, improve the organization and mechanical properties of the alloy ingot, and finally obtain a large-sized high-tin copper alloy ingot with both high plasticity and excellent cold rolling performance.

[0011] Preferably, in step (1), the smelting temperature is 1100-1190° C., and the smelting holding time is 5-9 min.

[0012] Preferably, in step (1), the cooling rate of the rapid quenching treatment is 400-450°C / s.

[0013] Preferably, in step (2), the temperature of the homogenization treatment is 990-1000° C., and the holding time of the homogenization treatment is 10-30 seconds.

[0014] Preferably, in step (3), the diameter of the mold is 80-100 mm, and the depth of the mold is 350-400 mm.

[0015] Preferably, in step (3), the cooling rate of the secondary quenching is 300-350°C / s.

[0016] Preferably, in step (3), the extrusion temperature is 520-550° C., the extrusion forming pressure is 145-175 MPa, and the extrusion insulation time is 2-3 min.

[0017] Preferably, in step (1), the smelting further includes slagging and standing steps.

[0018] Preferably, the temperature of the molten metal after standing is 1085-1095°C.

[0019] The present invention also provides a large-sized high-tin copper alloy ingot having both high plasticity and excellent cold rolling performance, which is prepared by the preparation method described in the above technical solution.

[0020] Compared with the prior art, the present invention has the following advantages and technical effects:

[0021] The invention prepares high-quality semi-solid metal slurry by smelting a high-tin copper alloy and performing rapid quenching and homogenization treatment, and then injects the high-quality semi-solid metal slurry into a mold, performs secondary quenching and extrusion, and utilizes the secondary quenching nucleation process technology of the mold wall to further prevent the generation of dendrites in the organization, improve the organization and mechanical properties of the alloy ingot, and finally obtain a large-sized high-tin copper alloy ingot with both high plasticity and excellent cold rolling performance.

[0022] The preparation method provided by the present invention completely eliminates the brittle δ phase in the alloy, saves the subsequent high-temperature and long-time heat treatment steps, realizes a short process and low cost, not only improves the production efficiency, but also achieves the purpose of energy saving and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 Schematic diagram of the structure of the semi-solid device in step (1) of Example 1;

[0025] Figure 2 Schematic diagram of the extrusion process in step (2) of Example 1;

[0026] Figure 3 The microstructure diagrams of the CuSn10P1 alloy ingots prepared in Comparative Example 3 and Example 1, wherein (a1)-(a3) are Comparative Example 3, and (b1)-(b3) are Example 1;

[0027] Figure 4 XRD diagram of the CuSn10P1 alloy ingots prepared in Comparative Example 3 and Example 1;

[0028] Figure 5 The tensile fracture surfaces and fracture profiles of the CuSn10P1 alloy ingots prepared in Comparative Example 3 and Example 1, wherein (a1)-(a2) are Comparative Example 3, and (b1)-(b2) are Example 3;

[0029] Figure 6 This is a physical picture of the CuSn10P1 alloy ingots prepared in Comparative Example 3 and Example 1 after cold rolling;

[0030] Figure 7 The engineering stress-strain curves of the CuSn10P1 alloy ingot prepared in Example 1 under different cold rolling reductions;

[0031] Figure 8 The tensile fracture diagrams of the CuSn10P1 alloy ingot prepared in Example 1 after cold rolling with different reductions, wherein (a) is 0 reduction, (b) is 20% reduction, (c) is 40% reduction, (d) is 60% reduction, and (e) is 80% reduction;

[0032] Fig. 9 It is the microstructure diagram of the CuSn10P1 alloy ingot prepared in Comparative Example 7, wherein (a2) is an enlarged view of (a1), and (a3) ​​is the Sn and P distribution diagram of (a2). DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] The embodiment of the present invention provides a method for preparing a large-sized high-tin copper alloy ingot having both high plasticity and excellent cold rolling performance, comprising the following steps:

[0036] (1) melting a high-tin copper alloy and then rapidly quenching the alloy to obtain a semi-solid metal slurry;

[0037] (2) homogenizing the semi-solid metal slurry obtained in step (1) to obtain high-quality semi-solid metal slurry;

[0038] (3) The high-quality semi-solid metal slurry obtained in step (2) is injected into a mold, and after secondary quenching and extrusion, a large-sized high-tin copper alloy ingot with high plasticity and excellent cold rolling performance is obtained.

[0039] In a preferred embodiment, in step (1), the grade of the high-tin copper alloy is CuSn10P1; in terms of mass percentage, the composition of CuSn10P1 is: tin (Sn) 9.0-11.5%, phosphorus (P) 0.8-1.1%, impurities ≤0.75%, and the balance is copper (Cu).

[0040] In a preferred embodiment, in step (1), the smelting temperature is 1100-1190°C, preferably 1130-1170°C; the smelting holding time is 5-9 minutes, and the smelting heating equipment is a medium frequency furnace.

[0041] In a preferred embodiment, in step (1), the smelting further includes slagging and standing steps.

[0042] In a preferred embodiment, the temperature of the molten metal after standing is 1085-1095°C.

[0043] In a preferred embodiment, in step (1), the cooling rate of the rapid chilling treatment is 400-450°C / s, preferably 420-440°C / s. The present invention controls the cooling rate of the rapid chilling treatment within the above range, which is conducive to obtaining a high-tin copper alloy ingot with both high plasticity and excellent cold rolling performance. Too fast or too slow cooling rate will reduce the plasticity and cold rolling performance of the alloy ingot.

[0044] In a preferred embodiment, in step (1), the equipment used for the rapid chilling treatment is a semi-solid device. The present invention adopts a semi-solid device to prepare a semi-solid metal slurry through a rapid chilling treatment, which has the following advantages: on the one hand, a large number of crystal nuclei are generated when the high-tin copper alloy liquid solidifies through the rapid chilling treatment; on the other hand, the fast-flowing metal liquid effectively breaks up the dendrites in the growth process, thereby significantly increasing the number of crystal nuclei in the melt during the solidification process, and effectively inhibiting the mutual annexation and growth of crystal nuclei. This process refines the grains and significantly reduces the quality defects of the high-tin copper alloy ingot, such as cracks, shrinkage cavities, shrinkage and pores, so that the material can be prevented from cracking during large plastic cold rolling deformation.

[0045] In a preferred embodiment, in step (2), the temperature of the homogenization treatment is 990-1000° C., and the holding time of the homogenization treatment is 10-30 seconds.

[0046] In a preferred embodiment, in step (3), the injection speed of injecting the high-quality semi-solid metal slurry into the mold is 80 to 140 cm 3 / s, preferably 100-110cm 3 / s; the injection method is injection along the mold wall.

[0047] In a preferred embodiment, in step (3), the diameter of the mold is 80-100 mm, preferably 80-90 mm; the depth of the mold is 350-400 mm, preferably 360-380 mm. The present invention adopts a large-diameter, high-depth mold to prepare a high-tin copper alloy ingot. On the one hand, it realizes the large-scale preparation of the high-tin copper alloy ingot. On the other hand, it ensures that the molten metal can effectively contact the mold wall when it reaches the bottom of the mold, achieving the purpose of secondary quenching, further ensuring the plasticity and cold rolling performance of the large-size high-tin copper alloy ingot, and effectively solving the technical problem that the traditional ingot size is small and the subsequent processing of large products cannot be carried out.

[0048] In a preferred embodiment, in step (3), the cooling rate of the secondary chilling is 300-350°C / s, preferably 320-340°C / s. The present invention controls the cooling rate of the secondary chilling within the above range, which is conducive to obtaining a high-tin copper alloy ingot with both high plasticity and excellent cold rolling performance. Too fast or too slow cooling rate will reduce the plasticity and cold rolling performance of the alloy ingot.

[0049] In a preferred embodiment, in step (3), the extrusion temperature is 520-550° C., preferably 530-550° C. The present invention performs extrusion within the above temperature range, which can eliminate the brittle δ phase in the alloy and ensure the plasticity and cold rolling performance of the alloy ingot. If the temperature is too low or too high, a large-sized high-tin copper alloy ingot with high plasticity and excellent cold rolling performance cannot be obtained.

[0050] In a preferred embodiment, in step (3), the extrusion forming pressure is 145-175 MPa, preferably 145-155 MPa. In the present invention, if the extrusion forming pressure is too low, the density of the ingot will be reduced, shrinkage and shrinkage cavities will be generated inside, and eventually the alloy ingot will crack during cold rolling. If the forming pressure is too high, the semi-solid metal slurry will seep out from the edge of the mold, affecting the alloy composition.

[0051] In a preferred embodiment, in step (3), the extrusion holding time is 2 to 3 minutes. If the extrusion holding time in the present invention is too short, the ingot will not be completely solidified, and microcracks will occur, resulting in poor mechanical properties of the alloy ingot and easy cracking during cold rolling.

[0052] In a preferred embodiment, in step (3), the extrusion punch running speed is 21 mm / min, and the holding time is 15 s; the cooling method after extrusion is air cooling.

[0053] In a preferred embodiment, in step (3), the heating process of extrusion is as follows: punch holes in the mold used for extrusion, and then insert a metal heating rod with a diameter of Φ 10 mm and a length of 100 mm for heating; when the mold temperature reaches the extrusion temperature, keep it warm for more than 1 hour to ensure that the temperature inside the mold is uniform, and then start extrusion.

[0054] The present invention also provides a large-sized high-tin copper alloy ingot having both high plasticity and excellent cold rolling performance, which is prepared by the preparation method described in the above technical solution.

[0055] The room temperature in the embodiments of the present invention refers to "25±2°C".

[0056] In the following examples, the chemical composition of the CuSn10P1 alloy used is calculated by weight percentage (Wt%): tin (Sn) 9.56%, phosphorus (P) 0.97%, impurities 0.08wt%, and the balance copper (Cu).

[0057] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.

[0058] Example 1 and Comparative Examples 1 to 3

[0059] A method for preparing a large-size high-tin copper alloy ingot with high plasticity and excellent cold rolling performance:

[0060] (1) 4.6 kg of CuSn10P1 alloy was cut and placed in a crucible, and then the crucible was placed in a medium frequency furnace and smelted at 1150° C. After the alloy was completely melted, the temperature was kept for 9 minutes to obtain molten metal; the obtained molten metal was slag-scraped and allowed to stand for cooling, and when the temperature dropped to 1085° C., the molten metal was quickly poured into a semi-solid device for rapid quenching treatment, and a crucible heated to 995° C. was used to receive the semi-solid metal slurry flowing out of the semi-solid device, and after homogenization treatment at 995° C. for 15 seconds, high-quality semi-solid metal slurry was obtained; wherein the cooling rate of the rapid quenching treatment was 420° C. / s;

[0061] (2) The high-quality semi-solid metal slurry obtained in step (1) is heated to 100 cm 3 / s speed along the mold wall into a mold with a diameter of 80mm and a depth of 350mm for secondary chilling and extrusion. The cooling rate of the secondary chilling is 330℃ / s. Before heating the mold, the Meishu 605 high-temperature release agent is sprayed. After the mold is punched, a metal heating rod with a diameter of 10mm and a length of 100mm is inserted for heating. When the mold temperature reaches the set extrusion temperature, it is kept warm for 1h and then extrusion is started; the extrusion temperature is set to: 410℃ (Comparative Example 1), 450℃ (Comparative Example 2), 490℃ (Comparative Example 3), 530℃ (Example 1), and the extrusion process parameters are: punch pressure (forming specific pressure) 145MPa, punch running speed 21mm / min, holding time 15s, after the holding period, the ingot is allowed to stand in the mold for 2min, and then air-cooled to room temperature to obtain a CuSn10P1 alloy ingot with a diameter of 80mm.

[0062] Figure 1 Schematic diagram of the structure of the semi-solid device in step (1) of Example 1.

[0063] Figure 2 Schematic diagram of the extrusion process in step (2) of Example 1. Figure 2 It can be seen that the present invention injects high-quality semi-solid metal slurry along the mold wall to achieve secondary quenching.

[0064] Figure 3The microstructure diagrams of the CuSn10P1 alloy ingots prepared in Comparative Example 3 and Example 1, wherein (a1)-(a3) are Comparative Example 3, and (b1)-(b3) are Example 1. Figure 3 From the (a1)-(a3) in FIG. 1 , it can be seen that the brittle δ phase (the phase indicated by the yellow arrow) can be clearly observed in the CuSn10P1 alloy ingot prepared in Comparative Example 1, while Figure 3 No brittle δ phase was observed in the (b1)-(b3) part of the graph. The phase indicated by the black arrow is Cu 3 P phase.

[0065] Figure 4 XRD diagram of the CuSn10P1 alloy ingots prepared in Comparative Example 3 and Example 1. Figure 4 It is further proved that there is no brittle δ phase in the CuSn10P1 alloy ingot prepared in Example 1, indicating that the brittle δ phase has been eliminated when the extrusion temperature is 530°C.

[0066] Performance Testing:

[0067] Tensile test: The CuSn10P1 alloy ingots prepared in Example 1 and Comparative Examples 1 to 3 were made into test samples with a gauge thickness of 2 mm, a width of 4 mm, and a length of 12 mm, and the stretching was performed at a stretching rate of 1 mm / min.

[0068] Cold rolling experiment: The CuSn10P1 alloy ingots prepared in Example 1 and Comparative Examples 1 to 3 were made into samples to be tested with a length of 20 mm, a width of 15 mm, and a height of 15 mm. The rolling mill roll diameter was set to 200 mm and the rolling speed was set to 3 r / min. At room temperature, the reduction amount of each rolling was 5%, and the rolling was stopped when the sample cracked. If the sample did not crack, it was rolled to a reduction amount of 80%.

[0069] The tensile strength and cold rolling performance results of the CuSn10P1 alloy ingots prepared in Example 1 and Comparative Examples 1 to 3 are shown in Table 1.

[0070] Table 1 Tensile strength and cold rolling properties of CuSn10P1 alloy ingots prepared in Example 1 and Comparative Examples 1 to 3

[0071]

[0072] It can be seen from Table 1 that with the increase of extrusion temperature, the elongation of the alloy ingot increases significantly, and the tensile strength increases and then decreases slightly.

[0073] Figure 5The tensile fracture surfaces and fracture cross-sections of the CuSn10P1 alloy ingots prepared in Comparative Example 3 and Example 1 are shown in FIG. 1 , wherein (a1) is the tensile fracture surface of Comparative Example 3, (b1) is the tensile fracture surface of Example 1, (a2) is the fracture cross-section of Comparative Example 3, and (b2) is the fracture cross-section of Example 1. Figure 5 It can be seen that the fracture mode of the CuSn10P1 alloy ingot prepared in Comparative Example 3 is intergranular fracture, while the fracture mode of the CuSn10P1 alloy ingot prepared in Example 1 is transgranular ductile fracture, and there are a large number of dimples on the fracture surface, which further proves that eliminating the δ phase is the key to improving the plasticity of the ingot.

[0074] Figure 6 This is a photo of the CuSn10P1 alloy ingots prepared in Comparative Example 3 and Example 1 after cold rolling. Figure 6 It can be seen that the CuSn10P1 alloy ingot prepared in Comparative Example 3 has surface cracks when cold rolled to a reduction of 50%, while the CuSn10P1 alloy ingot prepared in Example 1 has no surface cracks when cold rolled to a reduction of 80%.

[0075] The CuSn10P1 alloy ingot prepared in Example 1 was cold rolled to different reductions (0, 20%, 40%, 60%, 80%) during the cold rolling experiment to conduct mechanical property tests. The test results are shown in Tables 2 and Figure 7 .

[0076] Table 2 Mechanical properties of CuSn10P1 alloy ingots prepared in Example 1 after cold rolling to different reductions

[0077] Depression (%) Yield strength(MPa) Tensile strength(MPa) Elongation after break (%) 0 193.2 398 51.1 20 413.1 445.3 22.7 40 589.1 597.1 10.4 60 621.6 747.4 8.8 80 795.5 832.5 8.6

[0078] Figure 7 The engineering stress-strain curves of the CuSn10P1 alloy ingot prepared in Example 1 after cold rolling with different reductions. Figure 7 It can be seen that with the increase of rolling strain, the strength of the alloy ingot increases and the plasticity decreases. The elongation of 60% reduction is equivalent to that of 80% reduction, but the tensile strength increases by 85MPa. This is related to dislocation engineering. When the dislocation density reaches a range, the strength and plasticity can be improved at the same time.

[0079] Figure 8 The tensile fracture diagrams of the CuSn10P1 alloy ingot prepared in Example 1 after cold rolling with different reductions, where (a) is 0 reduction, (b) is 20% reduction, (c) is 40% reduction, (d) is 60% reduction, and (e) is 80% reduction. Figure 8 It can be seen that the fracture surfaces of the alloy ingots with different rolling reductions after stretching all show the characteristics of dimples, and the large dimples contain a large number of small dimples. With the increase of rolling reduction, the large dimples first decrease and then increase.

[0080] Example 2 and Comparative Examples 4-5

[0081] A method for preparing a large-size high-tin copper alloy ingot with high plasticity and excellent cold rolling performance:

[0082] Step (1) is the same as in Example 1;

[0083] (2) The high-quality semi-solid metal slurry obtained in step (1) is heated to 100 cm 3 / s speed along the mold wall into a mold with a diameter of 80mm and a depth of 350mm for secondary chilling and extrusion. The cooling rate of the secondary chilling is 330℃ / s. Before heating the mold, the Meishu 605 high-temperature release agent is sprayed. After the mold is punched, a metal heating rod with a diameter of 10mm and a length of 100mm is inserted for heating. When the mold temperature reaches the set extrusion temperature, it is kept warm for 1h, and then extrusion is started; the forming specific pressure of the extruder punch is set to: 85MPa (Comparative Example 4), 115MPa (Comparative Example 5), 175MPa (Example 2), respectively, and the other extrusion process parameters are: extrusion temperature 530℃, punch running speed 21mm / min, holding time 15s; after the holding pressure is completed, the ingot is allowed to stand in the mold for 2min, and then air-cooled to room temperature to obtain a CuSn10P1 alloy ingot with a diameter of 80mm.

[0084] The tensile strength and cold rolling performance results of the CuSn10P1 alloy ingots prepared in Examples 1-2 and Comparative Examples 4-5 are shown in Table 3.

[0085] Table 3 Tensile strength and cold rolling properties of CuSn10P1 alloy ingots prepared in Examples 1-2 and Comparative Examples 4-5

[0086]

[0087] It can be seen from Table 3 that with the increase of forming pressure, the elongation of the alloy ingot increases, and the tensile strength shows a trend of first increasing and then decreasing. At the same time, the low forming pressure reduces the density of the ingot, and the shrinkage and shrinkage cavities inside the ingot cause the material to crack during cold rolling. A higher forming pressure can improve the density of the internal structure of the ingot, but too high a forming pressure may cause the semi-solid metal slurry to seep out from the edge of the mold, affecting the alloy composition.

[0088] Example 3 and Comparative Example 6

[0089] A method for preparing a large-size high-tin copper alloy ingot with high plasticity and excellent cold rolling performance:

[0090] Step (1) is the same as in Example 1;

[0091] (2) The high-quality semi-solid metal slurry obtained in step (1) is heated to 100 cm 3 / s speed along the mold wall into a mold with a diameter of 80mm and a depth of 350mm for secondary chilling and extrusion. The cooling rate of the secondary chilling is 330℃ / s. Before heating the mold, the Meishu 605 high-temperature release agent is sprayed. After the mold is punched, a metal heating rod with a diameter of 10mm and a length of 100mm is inserted for heating. When the mold temperature reaches the set extrusion temperature, it is kept warm for 1h, and then extrusion is started; the extrusion process parameters are: extrusion temperature 530℃, forming specific pressure 145MPa, punch running speed 21mm / min, and holding time 15s; after the holding time, the ingot is left to stand in the mold for 1min (Comparative Example 6) and 3min (Example 3), respectively, and then air-cooled to room temperature to obtain a CuSn10P1 alloy ingot with a diameter of 80mm.

[0092] The tensile strength and cold rolling performance results of the CuSn10P1 alloy ingots prepared in Examples 1, 3 and Comparative Example 6 are shown in Table 4.

[0093] Table 4 Tensile strength and cold rolling properties of CuSn10P1 alloy ingots prepared in Examples 1, 3 and Comparative Example 6

[0094]

[0095] It can be seen from Table 4 that the mechanical properties of the ingot become extremely poor under the process of standing for 1 minute, which may be due to the fact that the ingot was taken out of the mold before it was completely solidified. During the process of taking out the ingot, the ingot that was not completely solidified produced microcracks, and the sample cracked when the cold rolling reduction was 80%. However, the elongation and tensile strength of the samples that were standing for 2 minutes and 3 minutes were excellent, and the samples did not crack when the cold rolling reduction was 80%.

[0096] Comparative Example 7

[0097] A method for preparing a CuSn10P1 alloy ingot:

[0098] The alloy ingot containing δ phase obtained at a mold temperature of 490°C (Comparative Example 3) was placed in a heat treatment furnace, subjected to homogenization heat treatment at 600°C for 120 hours, and then naturally cooled to room temperature to obtain a CuSn10P1 alloy ingot without δ phase.

[0099] Fig. 9 The microstructure diagram of the CuSn10P1 alloy ingot prepared in Comparative Example 7, wherein (a2) is an enlarged view of (a1), and (a3) ​​is a Sn and P distribution diagram of (a2). Fig. 9It can be seen that after the traditional homogenization heat treatment, although the brittle δ phase can be eliminated, the grain size of the alloy ingot increases and the number of holes increases. At the same time, the tensile strength of the ingot was measured to be 296MPa, the elongation after fracture was 49%, and the sample cracked when cold rolled to 80% reduction. In addition, this method has a long process flow, a long production cycle, and high cost. The presence of holes inside the alloy ingot will cause the material to crack during cold rolling.

[0100] Comparative Example 8

[0101] The difference from Example 1 is that in step (1), the cooling rate of the rapid quenching treatment is 360°C / s, and the rest is the same as Example 1.

[0102] Comparative Example 9

[0103] The difference from Example 1 is that in step (1), the cooling rate of the rapid quenching treatment is 480°C / s, and the rest is the same as Example 1.

[0104] Comparative Example 10

[0105] The difference from Example 1 is that in step (2), the high-quality semi-solid metal slurry obtained in step (1) is heated to 100 cm 3 / s speed along the mold wall into a mold with a diameter of 80mm and a depth of 300mm, and the rest is the same as in Example 1.

[0106] Comparative Example 11

[0107] The difference from Example 1 is that in step (2), the high-quality semi-solid metal slurry obtained in step (1) is heated to 100 cm 3 / s speed along the vertical center axis of the mold into a mold with a diameter of 80mm and a depth of 350mm, and the rest is the same as in Example 1.

[0108] Comparative Example 12

[0109] The difference from Example 1 is that in step (2), the extrusion temperature is 580° C., and the rest is the same as Example 1.

[0110] The tensile strength and cold rolling performance results of the CuSn10P1 alloy ingots prepared in Comparative Examples 8 to 12 are shown in Table 5.

[0111] Table 5 Tensile strength and cold rolling properties of CuSn10P1 alloy ingots prepared in Comparative Examples 8 to 12

[0112]

[0113] It can be seen from Table 5 that changing the cooling rate of the rapid chilling treatment, the depth of the mold, the injection method of the high-quality semi-solid metal slurry and the extrusion temperature will significantly reduce the tensile strength and cold rolling properties of the CuSn10P1 alloy ingot.

[0114] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing a large-sized high-tin copper alloy ingot having both high plasticity and excellent cold rolling performance, characterized in that: The following steps are involved: (1) melting a high-tin copper alloy and then rapidly quenching the alloy to obtain a semi-solid metal slurry; (2) homogenizing the semi-solid metal slurry obtained in step (1) to obtain high-quality semi-solid metal slurry; (3) The high-quality semi-solid metal slurry obtained in step (2) is injected into a mold, and after secondary quenching and extrusion, a large-sized high-tin copper alloy ingot with high plasticity and excellent cold rolling performance is obtained.

2. The preparation method according to claim 1, characterized in that: In step (1), the smelting temperature is 1100-1190° C., and the smelting holding time is 5-9 minutes.

3. The preparation method according to claim 1, characterized in that: In step (1), the cooling rate of the rapid quenching treatment is 400-450°C / s.

4. The preparation method according to claim 1, characterized in that: In step (2), the temperature of the homogenization treatment is 990-1000° C., and the holding time of the homogenization treatment is 10-30 seconds.

5. The preparation method according to claim 1, characterized in that: In step (3), the diameter of the mold is 80-100 mm, and the depth of the mold is 350-400 mm.

6. The preparation method according to claim 1, characterized in that: In step (3), the cooling rate of the secondary quenching is 300-350°C / s.

7. The preparation method according to claim 1, characterized in that: In step (3), the extrusion temperature is 520-550° C., the extrusion forming pressure is 145-175 MPa, and the extrusion insulation time is 2-3 min.

8. The preparation method according to claim 1, characterized in that: In step (1), the smelting process further includes slagging and standing steps.

9. The preparation method according to claim 8, characterized in that: The temperature of the molten metal after standing is 1085-1095°C.

10. A large-sized high-tin copper alloy ingot having high plasticity and excellent cold rolling performance, prepared by the preparation method according to any one of claims 1 to 9.

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