Tin bronze rod wire and method of making same

Abstract

The application discloses a tin bronze rod wire and a preparation method thereof. The tin bronze rod wire is composed of the following components in percentage by weight: Sn: 10-14 wt%, P: 0.05-0.3 wt%, Zn: 0.01-0.5 wt%, and the balance of Cu and inevitable impurities. The structure of the tin bronze rod wire includes alpha+delta+Cu3P ternary eutectic crystals, and the area ratio of the alpha+delta+Cu3P ternary eutectic crystals is less than or equal to 0.5%. The tin bronze rod wire has good mechanical properties.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of copper alloys, and particularly relates to a tin bronze rod wire and a preparation method thereof. BACKGROUND

[0002] Tin bronze is bronze with Sn as the main alloying element. The content of Sn is generally between 2-14%, and tin bronze is mainly used for making elastic elements, wear-resistant and corrosion-resistant parts. Tin bronze is a solid solution strengthening alloy. Sn has a strong solid solution strengthening effect in tin bronze, and the mechanical properties of tin bronze are improved with the increase of the content of Sn. Tin bronze alloy has a wide solidification temperature range. With the increase of the content of Sn, the problem of dendritic segregation in the as-cast structure is serious, and a large number of delta phases are distributed between dendrites. The delta phase is an electron compound Cu 31 Sn8-based solid solution with a complex cubic crystal structure, which is hard and brittle and cannot be plastically deformed. The delta phase in tin bronze will lead to a decrease in the plasticity of the alloy.

[0003] The patent application with the publication number CN114875270A discloses a tin phosphor bronze alloy. The mass percentage composition of the tin phosphor bronze alloy is as follows: Sn: 8.0-10.0%; P: 0.05-0.2%; In: 0.2-1.0%; Ni: 0.05-0.2%; Fe: ≤0.2%, other impurities: ≤0.2%, and the balance is Cu. The patent improves the cutting performance of the material by adding In elements to form easy-to-cut particles. Compared with Pb, In is harmless to human health and the environment, and the alloy still maintains good processing plasticity and mechanical properties, and also indirectly improves the electrical conductivity of the alloy. Through solid solution strengthening, fine-grain strengthening and work hardening, an excellent tin phosphor bronze alloy with comprehensive performance is obtained. However, the ternary eutectic content of the tin phosphor bronze alloy disclosed in the above patent is high, the processing performance is poor, and the plasticity still needs to be further improved.

[0004] The patent application with the publication number CN115404369A discloses a preparation method of tin-phosphor bronze wire rod. The tin-phosphor bronze has a mass percentage composition of Sn: 3.0-10.0wt%, P: 0.01-1.0wt%, and the balance of Cu and inevitable impurities. The preparation method comprises the following steps: 1) smelting; 2) casting; 3) high-temperature annealing; 4) hot extrusion: the extrusion temperature is 650-750℃, and the extrusion speed is 3-6mm / s to obtain an extruded blank; 5) stretching and annealing. Through high-temperature annealing and hot extrusion of the ingot and control of relevant parameters, the δ phase is reduced, the hot extrusion of the tin-phosphor bronze is realized, the compact blank is obtained, the foundation for obtaining the tin-phosphor bronze wire rod with smooth surface in the subsequent stretching is laid, and the high surface quality requirement of the tin-phosphor bronze wire rod in the electronic and communication industries is met. However, the tin-phosphor bronze wire rod has serious dendritic segregation, the content of α+δ+Cu3P ternary eutectic is high, and the strength and plasticity still have room for further improvement.

[0005] Since tin bronze usually needs to add a certain content of P to improve the casting performance and mechanical properties of the alloy, the α+δ+Cu3P ternary eutectic often appears in the as-cast structure of high-tin bronze, and the melting point of the ternary eutectic is about 628℃. The existence of the ternary eutectic makes the alloy exhibit thermal brittleness, so the high-tin bronze is prone to cracking during hot working. The high-tin bronze is usually produced by horizontal continuous casting. Although the cast blank produced by the horizontal continuous casting method can be cold worked, the plasticity of the cast blank is poor due to the existence of the ternary eutectic and many defects in the as-cast structure. Even if the cast blank is subjected to high-temperature homogenization treatment, the ternary eutectic can only be reduced to a certain extent. Moreover, after the long-time high-temperature homogenization treatment of the cast blank, the structure of the cast blank becomes very coarse. During the cold working deformation process of the cast blank, the orange peel phenomenon on the surface of the rod blank is serious, and the rod blank surface cracks when the deformation degree is large. The processing performance is poor, and the excellent mechanical properties cannot be obtained by utilizing the work hardening effect. SUMMARY

[0006] The application provides a tin bronze rod wire, which has good mechanical properties.

[0007] The application provides a tin bronze rod wire, which is composed of the following weight percentages of components: Sn: 10-14wt%, P: 0.05-0.3wt%, Zn: 0.01-0.5wt%, and the balance of Cu and inevitable impurities.

[0008] The structure of the tin bronze rod wire comprises α+δ+Cu3P ternary eutectic, and the area ratio of the α+δ+Cu3P ternary eutectic is ≤0.5%.

[0009] Sn: Sn has a strong solid solution strengthening effect in copper, with the increase of Sn content, the strength of tin bronze is also improved, when Sn content is more than 14%, the number of delta phase increases, the size becomes large, even the delta phase agglomeration occurs, the plasticity of tin phosphor bronze decreases obviously, the cold working performance is poor, and high strength is difficult to obtain through work hardening, therefore, the Sn content of the tin bronze in the application is 10-14%.

[0010] P: P can improve the wear resistance and casting performance of tin bronze, P can also be used as a deoxidizer to effectively reduce and control the generation of hard and brittle phase SnO2, so as to improve the mechanical properties of tin bronze. When the P content is more than 0.3wt%, P forms Cu3P with Cu, Cu3P forms a large amount of alpha+delta+Cu3P ternary eutectic with alpha phase and delta phase, and the melting point of the ternary eutectic is about 628℃. The existence of the ternary eutectic makes the alloy exhibit thermal brittleness, and cracking is easy to occur during hot working. When the P content is less than 0.05%, the effect of P on improving the casting performance and mechanical properties of the alloy is weak, therefore, the P content in the tin bronze of the application should be controlled in the range of 0.05-0.3wt%.

[0011] Zn: The addition of Zn can narrow the crystallization temperature range of tin bronze, improve the fluidity of the alloy in liquid state, and reduce the dendritic segregation. Zn can also be largely solid-solved in the alpha phase of tin bronze to improve the mechanical properties of tin bronze, and has almost no effect on the alloy structure. However, when the Zn content is more than 0.5wt%, the corrosion resistance of tin bronze is affected, therefore, the Zn content in the tin bronze of the application should be controlled in the range of 0.01-0.5wt%.

[0012] Preferably, the structure of the tin bronze rod wire further comprises twin crystals, and the area ratio of the twin crystals is 30-55%.

[0013] Twin crystal is a kind of grain that two crystals form a mirror symmetry orientation relationship along a common crystal face. Twin crystal is an important strengthening method for metal materials. For face-centered cubic metal materials, high proportion of twin crystals can improve the strength of the materials, but too high proportion of twin crystals will make the materials brittle. Moderate deformation is beneficial to the formation of annealed twin crystals.

[0014] Preferably, the inevitable impurities comprise Mn and Si, wherein Mn≤0.005wt% and Si≤0.005wt%.

[0015] Mn and Si are easy to oxidize to form metal oxides, and high content of Mn and Si can reduce the fluidity of the alloy melt. Under high tin content, dendritic segregation is easy to occur, therefore, the content of Mn and Si is controlled in a very low range in the application.

[0016] The selection and control of chemical composition have a direct impact on the formation and proportion of twin crystals. Different chemical compositions can lead to differences in crystal structure, which in turn affect the formation and proportion of twin crystals.

[0017] Preferably, the average grain size of the tin bronze rod wire is 3-15 μm. The size of the grain size has a great influence on the mechanical properties and processing properties of the metal. Generally, the finer and more uniform the grain is at room temperature, the better the overall performance of the material. However, if the grain size is too small, the total area of the grain boundary is larger, the dislocation obstacle is more, and the coordination of the grains with different orientations is more, which makes the resistance to plastic deformation of the metal higher. Therefore, too small grain size limits the improvement of the processing rate of the rod wire during cold working.

[0018] Preferably, the average aspect ratio of the grain of the tin bronze rod wire is 1-1.4. The grain aspect ratio refers to the ratio of the length to the diameter of the grain. The closer the value is to 1, the closer the grain shape is to equiaxed crystal. Compared with long grain, equiaxed crystal has more excellent mechanical properties because the size difference in each direction is smaller.

[0019] Further preferably, the average aspect ratio of the grain of the tin bronze rod wire is 1-1.2, and the structure of the tin bronze rod wire further comprises twin crystals, and the area proportion of the twin crystals is 36-55%.

[0020] In another aspect, the present application also provides a preparation method of the tin bronze rod wire. The process flow of the preparation method is: melting → semi-continuous casting → first homogenization annealing → hot extrusion → second homogenization annealing → intermediate stretching and annealing → finished product stretching → low-temperature annealing.

[0021] In the preparation method, the ingredients are prepared according to the mass percentage of each component of the tin bronze rod wire, and then melted.

[0022] The temperature of the second homogenization annealing is 600-680℃, and the holding time is 4-6h. If the time is less than 4h, the α+δ+Cu3P eutectic structure is still more, and if the time exceeds 6h, the grain grows to exceed 15μm.

[0023] Preferably, the intermediate stretching and annealing comprises a first stretching, a second stretching and a third stretching, each with a processing rate of 30-45%.

[0024] In the present application, the intermediate stretching and annealing with a medium processing rate not only can make the grain obtain a higher distortion energy, but also can further reduce the α+δ+Cu3P eutectic structure after annealing. In addition, the intermediate stretching and annealing after deformation can promote the formation of twin crystals.

[0025] Further preferably, the first intermediate annealing is performed on the billet after the first stretching, and the temperature of the first intermediate annealing is 520-600℃, and the holding time is 2-4h.

[0026] the second intermediate annealing temperature is 400-490 DEG C, and the holding time is 2-4h;

[0027] the third intermediate annealing temperature is 330-390 DEG C, and the holding time is 3-6h.

[0028] After each stretching and intermediate annealing, the content of alpha+delta+Cu3P eutectic structure is further reduced, therefore, in order to better control the grain size, the intermediate annealing temperature is formed in gradient change, so that the tin bronze rod wire provided by the application has better grain size while reducing the content of alpha+delta+Cu3P eutectic structure.

[0029] During the stretching deformation process, the annealing temperature and holding time affect the reduction effect of alpha+delta+Cu3P eutectic structure, the higher the temperature and the longer the holding time, the better the effect, but the grain size will grow, so the first annealing selects high temperature, and the holding time is 2-4h, the second and third annealing gradually reduce the annealing temperature to further reduce the alpha+delta+Cu3P eutectic structure, but mainly control the grain size, and the third annealing is low in temperature, and the recrystallization is fully completed by appropriately prolonging the time.

[0030] Preferably, the smelting temperature is 1100-1300 DEG C, the raw material is electrolytic plate, tin ingot and Cu-P intermediate alloy, a modifier is added to the copper water, the modifier is one or more of La / Ce mixed rare earth, Cu-Zr intermediate alloy and Cu-Ti intermediate alloy, and the total addition amount is 0.04-0.2wt%.

[0031] The added modifier of the application promotes solidification nucleation and inhibits columnar crystal growth, and when the addition amount of the modifier exceeds 0.2wt%, loose defects are generated in the ingot structure, and the performance is reduced.

[0032] Preferably, the semi-continuous casting is a vertical semi-continuous casting method, wherein the casting temperature is 1160-1280 DEG C, the cooling water inlet temperature is 20-35 DEG C, the cooling water pressure is 0.2-0.5 Mpa, the cooling water flow is 10-18 m 3 / h, the outlet water temperature is 25-45 DEG C, and the casting speed is 40-80 mm / min.

[0033] Preferably, the first uniform annealing temperature is 700-800 DEG C, and the holding time is 5-8h.

[0034] The high-tin-content tin bronze provided by the present application will produce serious dendritic segregation when solidifying, and the purpose of homogenizing annealing is to reduce the dendritic segregation, since Sn diffuses slowly in copper, in order to accelerate atomic diffusion, the homogenizing annealing temperature is as high as possible to shorten the homogenizing annealing time, and since the Sn content is high, the dendritic segregation is more serious, the homogenizing annealing temperature is 700-800 DEG C, and the holding time after reaching the temperature is 5-8h.

[0035] Preferably, the extrusion temperature of the hot extrusion is 700-860 DEG C, the extrusion speed of the hot extrusion is: the extrusion speed when the ingot extrusion is completed by 20-35% is 2-4mm / s, the extrusion speed when the ingot extrusion is completed by 35-65% is 4-7mm / s, and the extrusion speed when the ingot extrusion is completed by 70-85% is 7-10mm / s.

[0036] Further preferably, the extrusion temperature of the hot extrusion is 780-860 DEG C.

[0037] Preferably, the extrusion ratio of the hot extrusion is 10-120.

[0038] Since the present application needs to regulate the proportion of alpha + delta + Cu3P ternary eutectic and the proportion of twin crystal in the microstructure, on the one hand, increasing the extrusion temperature helps to reduce the number of alpha + delta + Cu3P ternary eutectic in the extrusion structure; on the other hand, since the twin crystal proportion increases with the increase of the volume fraction of recrystallization, the higher the extrusion temperature, the faster the extrusion dynamic recrystallization process, and the more sufficient the recrystallization degree, therefore, the present application needs to use a higher extrusion temperature, but if the extrusion temperature is too high, the extrusion is easy to crack, and the problem of high-temperature extrusion cracking can be improved by reducing the extrusion speed, therefore, the tin bronze of the present application should adopt high-temperature low-speed extrusion process, preferably the extrusion temperature is 780-860 DEG C, and the extrusion setting speed is dynamically adjusted, the starting extrusion speed of the ingot is 2-4mm / s, the extrusion speed is adjusted to 4-7mm / s when the ingot extrusion is completed by 35-65%, and the extrusion speed is adjusted to 7-10mm / s when the ingot extrusion is completed by 70-85%. The extrusion ratio provided by the present application is 10-120. If the extrusion ratio is lower than 10, the extrusion deformation degree is low, and the extrusion blank may retain part of the as-cast structure, and the processing performance of the extrusion blank is poor.

[0039] Preferably, the processing rate of the finished product stretching is more than 40%. The purpose of the finished product stretching is to obtain high mechanical properties through work hardening.

[0040] Preferably, the temperature of the low-temperature annealing is 180-260 DEG C, the temperature rising time is 30-60min, and the holding time is 120-300min.

[0041] The strength of the drawn rod wire is further improved by low-temperature annealing, because the low-temperature annealing reduces the number of movable dislocations in the material, and the Sn atoms are segregated on the layer dislocation surface and ordered to strengthen. The low-temperature annealing temperature is 180-260 DEG C, the time for increasing the temperature from room temperature to the temperature is 30-60 min, and the holding time is 120-300 min. If the annealing temperature is too low, the number of movable dislocations will not be reduced, and if the annealing temperature is too high, exceeding the starting recrystallization temperature of the alloy, the strength of the alloy will not be improved, but will be reduced due to recrystallization. If the temperature increasing time is too short, although the heating power of the temperature controller is reduced, the resistance wire lags in heating, so that the actual temperature of the furnace will temporarily exceed the set temperature, and then slowly decrease to the set temperature, which will change the properties of the material. If the temperature increasing time is too long, the holding time is prolonged, which will also change the properties of the material. If the holding time is too short, the strength will not be increased much, and if the holding time is too long, the strength may decrease.

[0042] Compared with the prior art, the present application has the following advantages:

[0043] By controlling the tin content at a high level, the tin bronze rod wire provided by the present application has high strength. Under the high tin content, the present application can also control the proportion of alpha + delta + Cu3P ternary eutectic to be not more than 0.5%, so that the tin bronze rod wire provided by the present application has good plasticity.

[0044] In the preparation of the tin bronze rod wire, a large number of alpha + delta + Cu3P ternary eutectic is eliminated by the first homogenization annealing and hot extrusion, and then the remaining alpha + delta + Cu3P ternary eutectic is further eliminated by controlling the temperature and annealing time of the second homogenization annealing, so that the area proportion of alpha + delta + Cu3P ternary eutectic is not more than 0.5%, and at the same time, good grain size can be ensured, so as to obtain a tin bronze rod wire with good strength and plasticity. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 The metallographic structure photo of the tin bronze rod wire prepared in Example 4 of the present application;

[0046] Figure 2 The metallographic structure photo of the tin bronze rod wire provided in Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0047] The present application will be further described in detail below in conjunction with the examples and drawings, but the embodiments of the present application are not limited thereto. In the examples, the specific conditions not mentioned are carried out according to the conventional conditions or the conditions recommended by the manufacturers.

[0048] The technical solutions of the present application are described in detail below using examples. The tensile strength Rm, yield strength Rp and elongation A50 in the examples are detected according to GB / T 228.1-2021 “Metallic Materials-Tensile Testing-Part 1: Method of Test at Room Temperature”. The phase proportion, twin crystal proportion, grain size and aspect ratio in the examples are observed under a metallographic microscope. 0.2 and elongation A50: detected according to GB / T 228.1-2021 “Metallic Materials-Tensile Testing-Part 1: Method of Test at Room Temperature”. The phase proportion, twin crystal proportion, grain size and aspect ratio in the examples are observed under a metallographic microscope.

[0049] Example 1

[0050] A specification of The preparation method of the high-strength tin-phosphor bronze bar is as follows:

[0051] 1) Melting and casting: the required components of the alloy are weighed, and electrolytic plates, tin ingots and Cu-P intermediate alloy are sequentially added to an electric furnace, the melting temperature is 1145-1255℃, after all the metals are melted, the alloy composition is tested, and after the alloy composition is qualified, a grain refiner is added in an amount of 0.074wt%, then the furnace head is tilted, and the vertical semi-continuous casting method is used to cast the ingot, the casting temperature is 1180-1240℃, the cooling water inlet temperature is 20℃, the cooling water pressure is 0.45Mpa, the cooling water flow rate is 13.8m3 / h, the outlet water temperature is 30℃, and the casting speed is 70mm / min, and the ingot specification is

[0052] 2) Homogenization annealing: in order to accelerate atomic diffusion and shorten the homogenization annealing time, the homogenization annealing temperature is as high as possible, and the homogenization annealing temperature is 740℃, and the holding time after reaching the temperature is 5.5h.

[0053] 3) Extrusion: high-temperature low-speed extrusion process is adopted, the extrusion temperature is 800℃, and the extrusion setting speed is dynamically adjusted, the starting extrusion speed of the ingot is 4mm / s, the extrusion speed of the ingot is adjusted to 6mm / s when the extrusion of the ingot is about 35-65%, the extrusion speed of the ingot is adjusted to 10mm / s when the extrusion of the ingot is about 70-85%, and the extrusion blank specification is The extrusion ratio is 32.

[0054] 4) Homogenization annealing: a lower homogenization annealing temperature should be used, The homogenization annealing temperature of the extrusion blank is 670℃, the heating time is 1h, the holding time after reaching the temperature is 5h, and the furnace is cooled to below 200℃ before being discharged.

[0055] 5) Intermediate drawing and annealing: The extrusion blank is drawn to The processing rate is 32.4%, the intermediate annealing temperature is 600℃, the heating time is 1.5h, and the holding time is 4h; to The processing rate is 34.3%, the intermediate annealing temperature is 490℃, the temperature rising time is 1h, and the holding time is 3.5h; After the third stretching, the diameter of the rod is The processing rate is 30.6%, the intermediate annealing temperature is 390℃, the temperature rising time is 0.5h, and the holding time is 5h.

[0056] 6) Product stretching: The blank is stretched to The rod, the processing rate of which is 48.2%.

[0057] 7) Low-temperature annealing: The annealing temperature of the rod is 190℃, the temperature rising time from room temperature to the temperature is 0.5h, and the holding time is 5h. The rod after the low-temperature annealing needs to be straightened.

[0058] 8) Inspection.

[0059] Example 2

[0060] Different from example 1, the second homogenizing annealing temperature and the annealing temperature after the intermediate three stretches are reduced, and the rest is the same as example 1. The influence of the homogenizing annealing temperature and the annealing temperature after the intermediate three stretches on the proportion of α+δ+Cu3P eutectic is investigated.

[0061] A specification of The preparation method of the high-strength tin-phosphorus bronze rod is as follows:

[0062] 1) Melting and casting: the required alloy components are prepared, and electrolytic plates, tin ingots and Cu-P intermediate alloy are sequentially added in an electric furnace, the melting temperature is 1145-1255℃, after all the metals are melted, the alloy components are tested, and after the test is qualified, a grain refiner is added, the addition amount is 0.074wt%, then the furnace head is tilted, and the vertical semi-continuous casting method is used to cast the ingot, the casting temperature is 1180-1240℃, the cooling water inlet temperature is 20℃, the cooling water pressure is 0.45Mpa, the cooling water flow is 13.8m3 / h, the outlet water temperature is 30℃, and the casting speed is 70mm / min, and the specification of the ingot is

[0063] 2) Homogenizing annealing: in order to accelerate atomic diffusion and shorten the homogenizing annealing time, the homogenizing annealing temperature is as high as possible, and the homogenizing annealing temperature is 740℃, and the holding time after reaching the temperature is 5.5h.

[0064] 3) Extrusion: high-temperature low-speed extrusion process is adopted, the extrusion temperature is 800℃, and the extrusion setting speed is dynamically adjusted, the starting extrusion speed of the ingot is 4mm / s, the extrusion speed of the ingot is adjusted to 6mm / s when the extrusion of the ingot is completed by about 35-65%, the extrusion speed of the ingot is adjusted to 10mm / s when the extrusion of the ingot is completed by about 70-85%, and the specification of the extruded blank is The extrusion ratio is 32.

[0065] 4) Homogenization annealing: lower homogenization annealing temperature should be adopted, The homogenization annealing temperature of the extruded blank is 630℃, the heating time is 1h, the holding time after reaching the temperature is 5h, and the furnace is cooled to below 200℃ before being discharged.

[0066] 5) Intermediate drawing and annealing: The extruded blank is drawn to The processing rate is 32.4%, the intermediate annealing temperature is 540℃, the heating time is 1.5h, and the holding time is 4h; to The processing rate is 34.3%, the intermediate annealing temperature is 450℃, the heating time is 1h, and the holding time is 3.5h; to The processing rate is 30.6%, the intermediate annealing temperature is 350℃, the heating time is 0.5h, and the holding time is 5h.

[0067] 6) Final drawing: The blank is drawn to The rod, the processing rate is 48.2%.

[0068] 7) Low temperature annealing: The annealing temperature of the rod is 190℃, the time for increasing from room temperature to this temperature is 0.5h, and the holding time is 5h. The rod after low temperature annealing needs to be straightened.

[0069] 8) Inspection.

[0070] Example 3

[0071] Different from example 1 is that the holding time of the second homogenization annealing and the holding time after the intermediate three-drawing are reduced, and the rest is the same as example 1. The influence of the holding time of the homogenization annealing and the holding time after the intermediate three-drawing on the proportion of α+δ+Cu3P eutectic is investigated.

[0072] A specification of The preparation method of high-strength tin-phosphorus bronze rod is as follows:

[0073] 1) Melting and casting: The ingredients of the alloy are prepared according to the required composition, and the electrolytic plate, tin ingot, and Cu-P intermediate alloy are sequentially added in the electric furnace. The melting temperature is 1145-1255°C. After all the metals are melted, the alloy composition is tested. When the composition is qualified, the grain refiner is added in an amount of 0.074wt%. Then, the furnace head is tilted, and the vertical semi-continuous casting method is used to cast the ingot. The casting temperature is 1180-1240°C. The cooling water inlet temperature is 20°C. The cooling water pressure is 0.45Mpa. The cooling water flow rate is 13.8m3 / h. The outlet water temperature is 30°C. The casting speed is 70mm / min. The ingot specification is

[0074] 2) Homogenization annealing: In order to accelerate atomic diffusion and shorten the homogenization annealing time, the homogenization annealing temperature is as high as possible. The homogenization annealing temperature is 740°C. The holding time after reaching the temperature is 5.5h.

[0075] 3) Extrusion: The high-temperature low-speed extrusion process is adopted. The extrusion temperature is 800°C. The set speed of extrusion is dynamically adjusted. The starting extrusion speed of the ingot is 4mm / s. When the ingot is extruded by about 35-65%, the extrusion speed is adjusted to 6mm / s. When the ingot is extruded by about 70-85%, the extrusion speed is adjusted to 10mm / s. The extrusion billet specification is The extrusion ratio is 32.

[0076] 4) Homogenization annealing: A lower homogenization annealing temperature should be adopted, The homogenization annealing temperature of the extrusion billet is 670°C. The heating time is 1h. The holding time after reaching the temperature is 4h. The furnace is cooled to below 200°C, and then the billet is taken out of the furnace.

[0077] 5) Intermediate drawing and annealing: The extrusion billet is drawn to The processing rate is 32.4%. The intermediate annealing temperature is 600°C. The heating time is 1.5h. The holding time is 2.5h. After the second drawing to The processing rate is 34.3%. The intermediate annealing temperature is 490°C. The heating time is 1h. The holding time is 2.5h. After the third drawing to The processing rate is 30.6%. The intermediate annealing temperature is 390°C. The heating time is 0.5h. The holding time is 3.5h.

[0078] 6) Final drawing: The billet is drawn to The rod, the processing rate is 48.2%.

[0079] 7) Low-temperature annealing: The bar annealing temperature is 190℃, the time for increasing from room temperature to the temperature is 0.5h, and the holding time is 5h. The bar after low temperature annealing needs to be straightened.

[0080] 8) Inspection.

[0081] Comparative Example 1

[0082] The chemical composition is controlled according to Example 1, and the conventional process route is: smelting→horizontal continuous casting Φ25→homogenizing annealing (680℃ / 6h)→drawing Φ18→straightening→inspection. The produced Φ18mm bar is produced.

[0083] The mass percentage of each component of Example 1-3 and Comparative Example 1 is shown in Table 1, and the microstructure is shown in Table 2.

[0084] Table 1 Chemical composition of Example 1-3 and Comparative Example 1

[0085] Number Sn P Zn Mn Si Cu Example 1 10.08 0.15 0.070 0.0041 0.0019 Balance Example 2 11.42 0.22 0.021 0.0035 0.0026 Balance Example 3 13.50 0.056 0.32 0.0033 0.0032 Balance Comparative Example 1 10.13 0.16 0.073 0.0047 0.0021 Balance

[0086] Table 2 Microstructure of Example 1-3 and Comparative Example 1

[0087]

[0088] As can be seen from Table 1 and Table 2, the significant reduction of α+δ+Cu3P eutectic and the appropriate grain size have a significant effect on the mechanical properties of tin bronze bar wire. Compared with Comparative Example 1, when the proportion of α+δ+Cu3P eutectic is less than 0.5% and the average grain size reaches 3-15μm, the tin bronze bar wire can achieve very high elongation and higher mechanical properties.

[0089] Example 4

[0090] A specification is The preparation method of high-strength tin-phosphor bronze bar is as follows:

[0091] 1) Smelting and casting: according to the required composition of the alloy, electrolytic plate, tin ingot and Cu-P intermediate alloy are sequentially added in the electric furnace, the smelting temperature is 1160-1260℃, after all the metals are melted, the alloy composition is tested, and after the test is qualified, the grain refiner is added, the addition amount is 0.09wt%, then the furnace head is tilted, and the vertical semi-continuous casting method is used to cast the ingot, the casting temperature is 1190-1250℃, the cooling water inlet temperature is 24℃, the cooling water pressure is 0.5Mpa, the cooling water flow is 15m3 / h, the outlet water temperature is 33℃, and the casting speed is 65mm / min. The ingot specification is

[0092] 2) Homogenization annealing: In order to accelerate atomic diffusion, shorten the homogenization annealing time, the homogenization annealing temperature is as high as possible, and the homogenization annealing temperature is 750℃, and the holding time after reaching the temperature is 6h.

[0093] 3) Extrusion: High-temperature low-speed extrusion process is adopted, the extrusion temperature is 820℃, and the extrusion setting speed is dynamically adjusted, the starting extrusion speed of the ingot is 4mm / s, the extrusion speed is adjusted to 6mm / s when the ingot extrusion is completed about 35-65%, the extrusion speed is adjusted to 10mm / s when the ingot extrusion is completed about 70-85%, and the extrusion blank specification is The extrusion ratio is 32.

[0094] 4) Homogenization annealing: A lower homogenization annealing temperature should be adopted, The homogenization annealing temperature of the extrusion blank is 650℃, the heating time is 1h, the holding time after reaching the temperature is 4h, and the furnace is cooled to below 200℃ and discharged.

[0095] 5) Intermediate drawing and annealing: The extrusion blank is drawn to The processing rate is 32.4%, the intermediate annealing temperature is 580℃, the heating time is 1.5h, and the holding time is 4h; Drawn to The processing rate is 34.3%, the intermediate annealing temperature is 470℃, the heating time is 1h, and the holding time is 3.5h; Drawn to The processing rate is 30.6%, the intermediate annealing temperature is 370℃, the heating time is 0.5h, and the holding time is 5h.

[0096] 6) Final drawing: The blank is drawn to The rod, the processing rate is 48.2%.

[0097] 7) Low temperature annealing: The rod annealing temperature is 200℃, the time from normal temperature to this temperature is 0.5h, and the holding time is 5h, and the rod after low temperature annealing needs to be straightened.

[0098] 8) Inspection.

[0099] Example 5

[0100] A specification of The preparation method of high-strength tin-phosphorus bronze wire rod is as follows:

[0101] 1) Melting and casting: The alloy was prepared according to the required composition, and electrolytic plate, tin ingot and Cu-P intermediate alloy were sequentially added in an electric furnace. The melting temperature was 1140-1270℃. After all the metals were melted, the alloy composition was tested. When the composition was qualified, grain refiner was added in an amount of 0.15wt%. Then, the furnace head was tilted, and the ingot was cast by vertical semi-continuous casting. The casting temperature was 1180-1240℃. The cooling water inlet temperature was 22℃. The cooling water pressure was 0.45Mpa. The cooling water flow rate was 13m3 / h. The outlet water temperature was 31℃. The casting speed was 80mm / min. The ingot specification was

[0102] 2) Homogenization annealing: In order to accelerate atomic diffusion and shorten the homogenization annealing time, the homogenization annealing temperature was as high as possible. The homogenization annealing temperature was 720℃. The holding time after reaching the temperature was 7h.

[0103] 3) Extrusion: High-temperature low-speed extrusion process was adopted. The extrusion temperature was 850℃. The set speed of extrusion was dynamically adjusted. The starting extrusion speed of the ingot was 3mm / s. When the ingot was extruded by about 35-65%, the extrusion speed was adjusted to 5mm / s. When the ingot was extruded by about 70-85%, the extrusion speed was adjusted to 9mm / s. The extrusion billet specification was The extrusion ratio was 82.

[0104] 4) Homogenization annealing: A lower homogenization annealing temperature should be adopted, The homogenization annealing temperature of the extrusion billet was 620℃. The heating time was 1h. The holding time after reaching the temperature was 4.5h. The billet was cooled to below 200℃ in the furnace and then taken out.

[0105] 5) Intermediate drawing and annealing: The extrusion billet was drawn to by the first drawing. The processing rate was 36%. The intermediate annealing temperature was 570℃. The heating time was 1.5h. The holding time was 3h. The billet was drawn to by the second drawing. The processing rate was 34%. The intermediate annealing temperature was 450℃. The heating time was 1h. The holding time was 3h. The billet was drawn to by the third drawing. The processing rate was 40.8%. The intermediate annealing temperature was 350℃. The heating time was 0.5h. The holding time was 5h.

[0106] 6) Final drawing: The billet was drawn to wire. The processing rate was 64%.

[0107] 7) Low-temperature annealing: The wire annealing temperature was 180℃. The time for increasing the temperature from room temperature to the annealing temperature was 0.5h. The holding time was 4h.

[0108] 8) Inspection.

[0109] Example 6

[0110] A specification is The high-strength tin-phosphor bronze bar is prepared as follows:

[0111] 1) Melting and casting: ingredients are prepared according to the required composition of the alloy, electrolytic plates, tin ingots, and Cu-P intermediate alloy are sequentially added in an electric furnace, the melting temperature is 1180-1270℃, after all the metals are melted, the alloy composition is tested, and the grain refiner is added after the alloy composition is qualified, the addition amount is 0.06wt%, then the furnace head is tilted, and the vertical semi-continuous casting method is used to cast the ingot, the casting temperature is 1200-1260℃, the cooling water inlet temperature is 17℃, the cooling water pressure is 0.5Mpa, the cooling water flow is 16m3 / h, the outlet water temperature is 28℃, and the casting speed is 55mm / min, and the ingot specification is

[0112] 2) Homogenization annealing: in order to accelerate atomic diffusion and shorten the homogenization annealing time, the homogenization annealing temperature is as high as possible, the homogenization annealing temperature is 780℃, and the holding time after reaching the temperature is 6h.

[0113] 3) Extrusion: high-temperature low-speed extrusion process is adopted, the extrusion temperature is 790℃, and the extrusion setting speed is dynamically adjusted, the starting extrusion speed of the ingot is 2mm / s, the extrusion speed of the ingot is adjusted to 4mm / s when the extrusion of the ingot is about 35-65%, the extrusion speed of the ingot is adjusted to 8mm / s when the extrusion of the ingot is about 70-85%, and the extrusion blank specification is The extrusion ratio is 32.

[0114] 4) Homogenization annealing: a lower homogenization annealing temperature should be adopted, The homogenization annealing temperature of the extrusion blank is 680℃, the heating time is 1h, the holding time after reaching the temperature is 5h, and the furnace is cooled to below 200℃ before being discharged.

[0115] 5) Intermediate drawing and annealing: The extrusion blank is drawn to The processing rate is 31.3%, the intermediate annealing temperature is 600℃, the heating time is 1.5h, and the holding time is 4h; to The processing rate is 31.5%, the intermediate annealing temperature is 490℃, the heating time is 1h, and the holding time is 3h; to The processing rate is 30.5%, the intermediate annealing temperature is 380℃, the heating time is 1h, and the holding time is 4.5h.

[0116] 6) Final drawing: The billet is drawn to The bar is drawn to

[0117] 7) Low temperature annealing: The bar annealing temperature is 200℃, the time for increasing temperature from room temperature to the annealing temperature is 0.5h, and the holding time is 5h. The bar after low temperature annealing needs to be straightened.

[0118] 8) Inspection.

[0119] Example 7

[0120] The bar is drawn to The preparation method of the high-strength tin-phosphor bronze wire rod is as follows:

[0121] 1) Melting and casting: ingredients required for the alloy are prepared, and electrolytic plates, tin ingots, and Cu-P intermediate alloy are sequentially added in an electric furnace, the melting temperature is 1135-1260℃, after all the metals are melted, the alloy composition is tested, and after the test shows that the alloy composition is qualified, a grain refiner is added in an amount of 0.18wt%, then the furnace head is tilted, and the vertical semi-continuous casting method is used to cast the ingot, the casting temperature is 1190-1250℃, the cooling water inlet temperature is 17℃, the cooling water pressure is 0.4Mpa, the cooling water flow rate is 12m3 / h, the outlet water temperature is 25℃, and the casting speed is 70mm / min, and the ingot specification is

[0122] 2) Homogenization annealing: in order to accelerate atomic diffusion and shorten the homogenization annealing time, the homogenization annealing temperature is as high as possible, the homogenization annealing temperature is 710℃, and the holding time after reaching the temperature is 6.5h.

[0123] 3) Extrusion: the high-temperature low-speed extrusion process is used, the extrusion temperature is 830℃, and the extrusion setting speed is dynamically adjusted, the starting extrusion speed of the ingot is 3.5mm / s, the extrusion speed is adjusted to 6mm / s when the ingot extrusion is about 35-65% complete, the extrusion speed is adjusted to 8mm / s when the ingot extrusion is about 70-85% complete, and the extrusion blank specification is The extrusion ratio is 60.5.

[0124] 4) Homogenization annealing: a lower homogenization annealing temperature should be used, The homogenization annealing temperature of the extrusion blank is 640℃, the temperature increasing time is 1h, the holding time after reaching the temperature is 4h, and the furnace is cooled to below 200℃ before the extrusion blank is taken out of the furnace.

[0125] 5) Intermediate drawing and annealing: The extrusion blank is drawn to The processing rate is 31.7%, the intermediate annealing temperature is 570℃, the temperature increasing time is 1.5h, and the holding time is 4h; The bar is drawn to The processing rate is 35%, the intermediate annealing temperature is 450℃, the temperature rising time is 1h, and the holding time is 3h; After the third stretching to The processing rate is 42.2%, the intermediate annealing temperature is 360℃, the temperature rising time is 0.5h, and the holding time is 4.5h.

[0126] 6) Product stretching: The blank is stretched to The wire rod has a processing rate of 50.8%.

[0127] 7) Low-temperature annealing: The wire rod annealing temperature is 190℃, the temperature rising time from normal temperature to the temperature is 0.5h, and the holding time is 4h.

[0128] 8) Inspection.

[0129] Comparative Example 2: C5240 brand Ф18mm rod is purchased.

[0130] In Example 4-7, the mass percentage of each component of Comparative Example 2 is shown in Table 3, and the microstructure is shown in Table 4.

[0131] Table 3 Chemical composition of Example 4-7 and Comparative Example 2

[0132]

[0133] Table 4 Microstructure of Example 4-7 and Comparative Example 2

[0134]

[0135] As can be seen from Table 3 and Table 4, higher twin crystal ratio and suitable grain aspect ratio can improve the mechanical properties of tin bronze rod wire. Under high tin content, the content of harmful elements Mn and Si is controlled below 0.005wt%, which can better realize higher mechanical properties.

[0136] As shown in Table 4, the average grain size is 12μm, the grain is fine, the average grain aspect ratio is 1.25, the value is close to 1, indicating that the grain is close to equiaxed crystal. The twin crystal ratio is 15.6%, although the number of twin crystals is not large, but the α+δ+Cu3P eutectic crystal accounts for only 0.15%, which is almost invisible, reaching the control range of the present application, so that Figure 1 the rod has excellent mechanical properties, corresponding to Example 4). Figure 1 As shown in Table 4, the average grain size is 12μm, the grain is fine, the average grain aspect ratio is 1.25, the value is close to 1, indicating that the grain is close to equiaxed crystal. The twin crystal ratio is 15.6%, although the number of twin crystals is not large, but the α+δ+Cu3P eutectic crystal accounts for only 0.15%, which is almost invisible, reaching the control range of the present application, so that

[0137] the rod has excellent mechanical properties, Figure 2As shown, the average grain size is 30 μm, the grains are relatively coarse, the average length-diameter ratio of the grains is 2.82, the value is far from 1, indicating that the grains are non-equiaxed crystals. The twin crystal proportion is only 15.6%, the number of twin crystals is small, and the α+δ+Cu3P eutectic (black spots) accounts for 5.73%, more than 0.5%, and the number is relatively large, all of which are not within the control range of the present application, so that The mechanical properties of the bar are poor, Figure 2 Comparative Example 1).

Claims

1. A tin bronze bar wire, characterized by, The tin bronze bar wire is composed of the following components by weight percentage: Sn: 10.08-14wt%, P: 0.05-0.3wt%, Zn: 0.01-0.5wt%, the balance being Cu and inevitable impurities; The microstructure of the tin bronze bar wire includes α+δ+Cu3P ternary eutectic, and the area percentage of the α+δ+Cu3P ternary eutectic is ≤0.5%; The microstructure of the tin bronze bar wire also includes twin crystals, and the area percentage of the twin crystals is 30-55%; The average grain size of the tin bronze bar wire is 3-15μm.

2. The tin bronze rod wire of claim 1, wherein, The inevitable impurities include Mn and Si, wherein Mn≤0.005wt% and Si≤0.005wt%.

3. The tin bronze rod wire of claim 1, wherein, The average aspect ratio of the grains of the tin bronze bar wire is 1-1.

4.

4. A process for the production of a tin bronze bar wire according to any one of claims 1 to 3, characterized in that The process flow of the preparation method is: melting → semi-continuous casting → first homogenization annealing → hot extrusion → second homogenization annealing → intermediate drawing and annealing → finished product drawing → low-temperature annealing; The components are proportioned according to the tin bronze bar wire of any one of claims 1-3 in terms of mass percentage; The temperature of the second homogenization annealing is 600-680℃, and the holding time is 4-6h; The temperature of the first homogenization annealing is 700-800℃, and the holding time is 5-8h.

5. The method of producing a tin bronze rod wire according to claim 4, characterized by, The intermediate drawing and annealing include a first drawing, a second drawing and a third drawing, each with a processing rate of 30-45%.

6. The method of producing a tin bronze rod wire according to claim 5, characterized by, The first intermediate annealing is performed on the blank after the first drawing, and the temperature of the first intermediate annealing is 520-600℃, and the holding time is 2-4h; The second intermediate annealing is performed on the blank after the second drawing, and the temperature of the second intermediate annealing is 400-490℃, and the holding time is 2-4h; The third intermediate annealing is performed on the blank after the third drawing, and the temperature of the third intermediate annealing is 330-390℃, and the holding time is 3-6h.

7. The method of producing a tin bronze rod wire according to claim 4, characterized by, The extrusion temperature of the hot extrusion is 700-860℃, and the extrusion speed of the hot extrusion is: 2-4mm / s when 20-35% of the ingot extrusion is completed, 4-7mm / s when 35-65% of the ingot extrusion is completed, and 7-10mm / s when 70-85% of the ingot extrusion is completed.

8. The method of producing a tin bronze rod wire according to claim 4, characterized by, The temperature of the low-temperature annealing is 180-260℃, the temperature rising time is 30-60min, and the holding time is 120-300min.

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