CN114875270A

CN114875270A - Tin-phosphor bronze alloy and preparation method thereof

Info

Publication number: CN114875270A
Application number: CN202210510732.XA
Authority: CN
Inventors: 郑恩奇; 叶东皇; 巢国辉; 傅杰
Original assignee: Ningbo Jintian Copper Group Co Ltd
Current assignee: Ningbo Jintian Copper Group Co Ltd
Priority date: 2022-05-11
Filing date: 2022-05-11
Publication date: 2022-08-09
Anticipated expiration: 2042-05-11
Also published as: CN114875270B

Abstract

The invention discloses a tin-phosphor bronze alloy, which is characterized in that: the tin-phosphor bronze alloy comprises the following components in percentage by mass: 8.0-10.0%; p: 0.05-0.2%; in: 0.2-1.0%; ni: 0.05-0.2%; fe: less than or equal to 0.2 percent, and other impurities: less than or equal to 0.2 percent and the balance of Cu. The invention improves the machinability of the material by adding In element to form free-cutting particles. Compared with Pb, the In is environment-friendly and harmless to human health, on the other hand, the alloy still keeps good processing plasticity and mechanical property, and the conductivity of the alloy is also indirectly improved, the tin-phosphor bronze alloy with excellent comprehensive performance is obtained through various modes such as solid solution strengthening, fine grain strengthening, work hardening and the like, the tensile strength of the tin-phosphor bronze alloy is more than or equal to 1000MPa, the elongation is more than or equal to 3%, the cutting index is more than 70% of C36000, the conductivity is more than or equal to 15% IACS, and the high temperature softening resistance temperature is more than or equal to 370 ℃.

Description

Tin-phosphor bronze alloy and preparation method thereof

Technical Field

The invention belongs to the technical field of copper alloy, and particularly relates to a tin-phosphor bronze alloy and a preparation method thereof.

Background

The tin bronze has higher strength, elasticity and wear resistance due to the addition of tin element, and is widely applied to the fields of elastic elements, precision instrument parts, wear-resistant parts and the like. At present, the tin bronze is mainly Cu-Sn-P and Cu-Sn-Zn-P. Wherein the Cu-Sn-P series tin-phosphor bronze is strengthened by Sn element solid solution and Cu ₃ The formation of the P phase significantly improves the strength, hardness and elasticity of the alloy. However, Cu-Sn-P series bronze has poor cutting performance, turning chips are easy to curl and wind the cutter during high-speed turning, the chips are not easy to break, meanwhile, the strength and hardness of the material are greatly improved along with the increase of the Sn content, the higher hardness enables the abrasion degree of the cutter to be larger, and the service life of the cutter is greatly shortened. The Cu-Sn-Zn-Pb series tin-zinc-lead bronzes improve the alloy cutting performance by adding zinc and lead elements aiming at the problem of poor cutting of the former series, but the alloy has poor cold and hot processing performance after the lead element is added, so that the alloy is not suitable for hot and cold processing forming with large processing rate, and the lead element is harmful to human health and is not environment-friendly, so the Cu-Sn-Zn-Pb series bronzes have good cutting performance, but the mechanical properties such as material strength, elasticity, hardness and the like are obviously lower than those of the Cu-Sn-P series.

The tin bronze series alloy is mainly used for increasing the strength of the material in a work hardening mode, and when the cold working rate is high, the high-temperature softening resistance of the material is poor, so that the material can still keep the high-strength characteristic under a certain high-temperature condition by adding a certain amount of Ni element.

Aiming at the limitations of the Cu-Sn-P and Cu-Sn-Zn-Pb series tin bronzes, the invention aims to develop a Cu-Sn-P series alloy with mechanical properties and easy cutting processability close to that of the Cu-Sn-Zn-Pb series alloy.

Disclosure of Invention

The first technical problem to be solved by the invention is to provide the tin-phosphor bronze alloy with excellent comprehensive properties of strength, elongation, cutting performance, electric conductivity and high-temperature softening resistance.

The technical scheme adopted by the invention for solving the first technical problem is as follows: a tin-phosphor bronze alloy characterized by: the tin-phosphor bronze alloy comprises the following components in percentage by mass: 8.0-10.0%; p: 0.05-0.2%; in: 0.2-1.0%; ni: 0.05-0.2%; fe: less than or equal to 0.2 percent, and other impurities: less than or equal to 0.2 percent and the balance of Cu.

The alloy is based on Cu-Sn-P series, wherein Sn plays a role in solid solution strengthening, the content of Sn is controlled within the range of 8-10%, and the alloy can be ensured to have high strength and hardness. If the Sn content is lower than 8%, the alloy strengthening effect is not obvious, and if the Sn content is higher than 10%, the material strength is not obviously improved, and the brittleness of the material is further increased, so that the processing performance and the mechanical property of the material are reduced. Meanwhile, if the Sn content is too high, the alloy casting difficulty is further increased, and the structure segregation and the blank cracking are easily caused.

The addition of the P element plays roles of degassing and deoxidizing in the casting process on one hand, and can improve the strength of the alloy on the other hand. The upper limit of the P content is controlled to be below 0.2 percent, the purpose is to avoid reducing the processing plasticity and the conductivity of the alloy, and meanwhile, the material brittleness is increased and the mechanical property of the alloy is reduced due to the over-high P content.

The addition of the In element mainly plays a role In improving the cutting performance of the material. The In-delta phase with low melting point is formed by cooperating with Sn element, the action of the In-delta phase is similar to that of Pb element, and the In-delta phase plays a role In reducing friction and lubricating during material machining, so that the alloy has good cutting performance. Meanwhile, the In element can increase the critical current density of the material, thereby improving the conductivity. Under certain processing conditions, the In element can promote the formation of gas mass dislocation to improve the strength of the material, and compared with Pb element, the In element has obvious brittleness characteristic, and the addition of the In element can not obviously reduce the strength of the material.

The Ni element is added to improve the strength of the alloy and further improve the high-temperature softening resistance of the alloy. The tin bronze series alloy is mainly used for increasing the strength of the material in a work hardening mode, and when the cold working rate is high, the high-temperature softening resistance of the material is poor, so that the material can still keep the high-strength characteristic under a certain high-temperature condition by adding a certain amount of Ni element.

Preferably, the microstructure of the tin-phosphor bronze alloy contains an In-delta phase, and the average size of the In-delta phase is controlled to be 0.1-2.0 mu m and 1mm ² The number of In-delta phases precipitated per unit area is controlled to be 6000 or more. Good machinability is obtained by controlling the size and the number of In-delta phases per unit area without reducing the strength of the material.

Preferably, the tin-phosphor bronze alloy has the tensile strength of more than or equal to 1000MPa, the elongation of more than or equal to 3 percent, the cutting index of more than 70 percent of C36000, the electric conductivity of more than or equal to 15 percent IACS and the high-temperature softening resistance temperature of more than or equal to 370 ℃.

The second technical problem to be solved by the invention is to provide a preparation method of the tin-phosphor bronze alloy.

The technical scheme adopted by the invention for solving the second technical problem is as follows: a tin-phosphor bronze alloy characterized by: the preparation method comprises the following preparation steps:

1) smelting: proportioning according to the required components;

2) casting: and (2) adopting a horizontal continuous casting mode to cast a blank, wherein the traction speed is 0.2-1.0 m/min, the traction pitch is 1-3 mm, and the reverse-thrust length is as follows: 0.1-0.5 mm, cooling water pressure: 0.5-0.8 Mpa, cooling water inlet temperature: 15-25 ℃, water outlet temperature: controlling the casting temperature to be 1190-1220 ℃ at 20-40 ℃;

3) homogenizing and annealing: carrying out homogenization annealing treatment on the blank, wherein the annealing temperature range is as follows: 680-720 ℃, the heat preservation time is 6-10 h, quenching treatment is carried out on the homogenized blank after the heat preservation time is reached, and the water inlet time after discharging is controlled within 30 s;

4) first stretching: stretching the blank after the homogenizing annealing, wherein the processing rate is controlled to be 10-35%; after stretching is finished, peeling treatment is carried out, and the peeling amount is 0.2-1 mm;

5) intermediate high-temperature annealing: annealing the stretched blank, wherein the annealing temperature range is as follows: keeping the temperature at 520-600 ℃ for 2-5 h;

6) and (3) second stretching: stretching the blank subjected to intermediate high-temperature annealing, wherein the second-pass stretching processing rate is controlled to be 30-60%;

7) intermediate low-temperature annealing: annealing the stretched blank, wherein the annealing temperature range is as follows: keeping the temperature at 350-450 ℃ for 3-10 h;

8) and (3) finished product stretching: and (3) stretching the blank subjected to intermediate low-temperature annealing, wherein the finished product stretching is carried out in 2-4 passes, and the processing rate of each pass is controlled as follows: 10-30% and the total stretching processing rate is 40-70%;

9) stress relief annealing: and (3) performing stress relief annealing on the finished bar, and performing atmosphere protection, wherein the heating speed is controlled to be 5-10 ℃/min, the heat preservation temperature is controlled to be 150-200 ℃, and the heat preservation time is 4-12 h.

The casting process of the steps controls the lower traction speed, increases the pressure of the cooling water and strictly controls the temperature of the cooling water inlet and outlet water, so that the thickness of the solidified shell is continuously thickened, and the solidified shell has enough strength to be led out from the crystallizer. The reverse thrust is set, and the reverse thrust amount is set to be 0.1-0.5 mm, so that the melt is compressed when being solidified, and the crystalline structure is more compact; and secondly, the vibration effect is achieved during crystallization, crystal grains are refined, the number of radial columnar crystals is reduced, so that the strength and plasticity of the casting blank are improved, the area percentage of the finally obtained horizontal continuous casting blank radial columnar crystals is controlled to be below 50%, the smaller the number of the radial columnar crystals is, the higher the plasticity of the casting blank is, the tensile strength and the elongation of the casting blank can respectively reach above 400MPa and 20%, and the good subsequent cold processing performance is achieved.

The steps are homogenized and annealed, and the purpose is as follows: because the Sn content of the alloy is high, the Sn element segregation problem needs to be eliminated by adopting high homogenizing annealing temperature, and the lower limit temperature of 680 ℃ is set to ensure that the Sn content deviation of the center and the edge of the blank is controlled within 0.3 percent. Purpose two: greatly improves the processing plasticity of the blank, has the elongation rate of more than 70 percent, and meets the requirement of the subsequent large processing rate stretching. The upper limit temperature of 720 ℃ is set to avoid excessive growth of crystal grains due to overhigh temperature, which causes uneven structure, and material thermal cracking due to overhigh temperature. After reaching the holding time, the homogenized blank is quenched to maintain a high-temperature phase, and the high-temperature phase is characterized in that: the alpha phase and the In-delta phase are distributed, wherein the In-delta phase is uniformly distributed In particle particles, the aggregation and growth of the In-delta phase are reduced as much as possible, and the In-delta phase is converted into a dendritic phase, and if the In-delta phase is distributed In a large-area dendritic phase, the improvement of the processing plasticity of the material is not facilitated.

The first stretching in the steps is carried out, the processing rate is controlled to be 10-35%, the material is subjected to certain processing hardening, the subsequent peeling procedure can be smoothly carried out, and the phenomenon of nonuniform peeling caused by high plasticity is avoided. After peeling off, the fine defects such as surface crystal grains and the like can be eliminated, and the surface quality of the blank is improved.

The high-temperature annealing in the middle of the steps enables the blank structure after the first drawing to be recrystallized, the longitudinal strip-shaped processing structure is effectively eliminated, the area proportion of 80 percent before the annealing is reduced to be within 10 percent, the uniformity of the structure is improved, the upper limit temperature of 600 ℃ is controlled, the average grain size of the structure is effectively controlled to be below 30 mu m, and the elongation is more than 60 percent. If the temperature is further increased, the plasticity is not obviously improved, so that the annealing temperature is controlled within the range of 520-600 ℃ to ensure that the structure is recrystallized and the plasticity of the material keeps ideal processing conditions.

The intermediate low-temperature annealing in the steps can effectively improve the plasticity of the blank, the elongation after annealing can reach more than 50 percent, and the lower annealing temperature effectively controls the average grain size of the structure to be less than 5 mu m, thereby achieving the purpose of fine grain strengthening. If the temperature is further increased, the crystal grains tend to grow, and the effect of fine grains cannot be realized. The second stretching processing rate is controlled to be 30-60% in combination with the steps, and the recrystallization temperature can be reduced by a larger processing rate, so that the ideal conditions of fine grains and high plasticity can be realized under the annealing condition in a lower temperature range by the intermediate low-temperature annealing process in the step.

Stretching the finished product in the steps, wherein the stretching of the finished product is carried out in 2-4 passes, and the processing rate of each pass is controlled as follows: 10 to 30 percent. The alloy is stretched in multiple passes, residual stress formed in the stretching process can be eliminated uniformly, the axial and radial residual stress values are controlled within 200MPa, and the phenomenon that the residual stress is overlarge after single-pass high-machining-rate machining is avoided. If the residual stress is too large, the strength and plasticity of the material are reduced. The total processing rate is controlled to be 40-70%, and the purpose is to fully utilize the processing hardening effect of the material and provide the tensile strength of a finished product.

The stress relief annealing in the steps aims to further eliminate the internal stress of the hard bar of the finished product, control the axial residual stress value and the radial residual stress value within 80MPa and improve the performance uniformity of the finished product. Meanwhile, the low-temperature long-time heat preservation annealing is beneficial to further improving the strength and the hardness of the material. After the stress relief annealing of the finished product, the tensile strength of the material is stabilized above 1000MPa, and the elongation is kept above 3%.

Preferably, in the step 2), the area ratio of the radial columnar crystals of the obtained ingot is controlled to be 50% or less.

Preferably, In the step 3), after annealing, the Sn content deviation of the center and edge parts of the blank is controlled within 0.3%, the In-delta phase is granular, and the elongation of the blank is more than 70%.

Preferably, in the step 5), the area ratio of the longitudinal long processed structure in the annealed blank is reduced to be within 10%, the average grain size of the structure is below 30 μm, and the elongation is above 60%.

Preferably, in the step 7), the average grain size of the structure after annealing is 5 μm or less, and the elongation is 50% or more.

Preferably, in the step 8), the axial residual stress value and the radial residual stress value of the bar after stretching are both controlled within 200 MPa.

Preferably, in the step 9), the axial residual stress value and the radial residual stress value of the bar after annealing are both controlled within 80 MPa.

Compared with the prior art, the invention has the advantages that: the invention improves the machinability of the material by adding In element to form free-cutting particles. Compared with Pb, the In is environment-friendly and harmless to human health, on the other hand, the alloy still keeps good processing plasticity and mechanical property, and the conductivity of the alloy is also indirectly improved, the tin-phosphor bronze alloy with excellent comprehensive performance is obtained through various modes such as solid solution strengthening, fine grain strengthening, work hardening and the like, the tensile strength of the tin-phosphor bronze alloy is more than or equal to 1000MPa, the elongation is more than or equal to 3%, the cutting index is more than 70% of C36000, the conductivity is more than or equal to 15% IACS, and the high temperature softening resistance temperature is more than or equal to 370 ℃.

Drawings

FIG. 1 is a metallographic structure photograph of example 1 of the present invention.

FIG. 2 is a metallographic structure photograph of comparative example 1 of the present invention.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.

The invention provides 4 examples and 2 comparative examples, the specific components of which are shown in Table 1.

Example 1

1) Smelting: proportioning according to the component requirements, sequentially adding an electrolytic plate, a tin ingot, metal indium and a nickel ingot into an intermediate frequency furnace, heating, controlling the initial temperature to be 1220 ℃, adding a slag removing agent after the raw materials are completely melted, uniformly stirring for 4min, adding a copper-phosphorus alloy, controlling the smelting temperature to be 1200 ℃, and uniformly stirring the melt. And (4) sampling and testing, transferring to a heat preservation furnace after the components are tested to be qualified, adding charcoal to cover, and covering with the thickness of 50 mm.

2) Casting: and (4) adopting a horizontal continuous casting mode to cast a blank. Wherein the traction speed is 0.3m/min, the traction pitch is 2mm, the reverse thrust length: 0.2mm, cooling water pressure: 0.6Mpa, cooling water inlet temperature: 18-25 ℃, water outlet temperature: 25-35 ℃, the casting temperature is controlled at 1200 ℃, and the traction blank specification is as follows:

3) homogenizing and annealing: placing the blank in a well type furnace for homogenizing annealing treatment, wherein the annealing temperature is as follows: 690 ℃ and the heat preservation time is 8 h. And quenching the homogenized blank after the heat preservation time is reached, and controlling the water inlet time after the homogenized blank is discharged from the furnace within 30 s.

4) First stretching: pickling the blank after the homogenizing annealing, placing the blank in an inverted disc drawing machine for drawing, wherein the total processing rate of the first drawing is 34%, and peeling is carried out after the drawing is finished, wherein the peeling amount is 0.5mm, so that the blank is obtained

And (5) coiling a round bar blank.

5) Intermediate high-temperature annealing: placing the stretched hard blank in a pit furnace for annealing treatment, wherein the annealing temperature is as follows: keeping the temperature at 550 ℃ for 3 h.

6) And (3) second stretching: pickling the blank subjected to intermediate high-temperature annealing, placing the blank in an inverted disc drawing machine for drawing, wherein the total processing rate of the second drawing is 52 percent, and obtaining the alloy

And (5) coiling a round bar blank.

7) Intermediate low-temperature annealing: and (3) placing the stretched hard blank in a pit furnace for annealing treatment, wherein the annealing temperature is as follows: keeping the temperature at 400 ℃ for 5 h.

8) And (3) finished product stretching: and (4) pickling the blank subjected to intermediate low-temperature annealing, and then placing the blank in a drawing machine for drawing and straightening. The finished product is stretched in 4 passes, the processing rate of each pass is controlled within 30 percent, the total processing rate of stretching is 56 percent, and the finished product is obtained by sizing and sawing after stretching

And (5) finishing the bar.

9) Stress relief annealing: and (4) placing the finished bar material subjected to fixed-length saw cutting into a box-type furnace for stress relief annealing, and using an ammonia decomposition atmosphere to protect the annealing mode. The heating speed is 10 ℃/min, the heat preservation temperature is 200 ℃, and the heat preservation time is 5 h.

10) Straightening: and (5) straightening the finished bar, and packaging and warehousing after the finished bar is detected to be qualified.

Example 2

1) Smelting: proportioning according to the component requirements, sequentially adding an electrolytic plate, a tin ingot, metal indium and a nickel ingot into an intermediate frequency furnace, heating, controlling the initial temperature to be 1240 ℃, adding a slag removing agent after the raw materials are completely melted, uniformly stirring for 4min, adding a copper-phosphorus alloy, controlling the smelting temperature to be 1200 ℃, and uniformly stirring the melt. And (4) sampling and testing, transferring to a heat preservation furnace after the components are tested to be qualified, adding charcoal to cover, and covering with the thickness of 50 mm.

2) Casting: and (4) adopting a horizontal continuous casting mode to cast a blank. Wherein the traction speed is 0.4m/min, the traction pitch is 2mm, the reverse-thrust length: 0.1mm, cooling water pressure: 0.8Mpa, cooling water inlet temperature: 18-25 ℃, water outlet temperature: 25-35 ℃, and controlling the casting temperature at 1200 ℃. The traction blank specification is as follows:

3) homogenizing and annealing: placing the blank in a well type furnace for homogenizing annealing treatment, wherein the annealing temperature range is as follows: the temperature is 680 ℃, and the heat preservation time is 6 h. And quenching the homogenized blank after the heat preservation time is reached, and controlling the water inlet time after the homogenized blank is discharged from the furnace within 30 s.

4) First stretching: placing the blank after the homogenizing annealing in an inverted disc drawing machine for drawing after acid washing treatment, wherein the total processing rate of the first drawing is 29 percent, and peeling treatment is carried out after the drawing is finished, wherein the peeling amount is 0.5mm, thus obtaining the product

And (5) coiling a round bar blank.

5) Intermediate high-temperature annealing: placing the stretched hard blank in a pit furnace for annealing treatment, wherein the annealing temperature is as follows: keeping the temperature at 530 ℃ for 4 h.

6) And (3) second stretching: pickling the blank subjected to intermediate high-temperature annealing, placing the blank in an inverted disc drawing machine for drawing, wherein the total processing rate of the second drawing is 45 percent, and obtaining the alloy

And (5) coiling a round bar blank.

7) Intermediate low-temperature annealing: and (3) placing the stretched hard blank in a pit furnace for annealing treatment, wherein the annealing temperature is as follows: keeping the temperature for 4h at 420 ℃.

8) And (3) finished product stretching: and (4) pickling the blank subjected to intermediate low-temperature annealing, and then placing the blank in a drawing machine for drawing and straightening. The finished product is stretched in 4 passes, the processing rate of each pass is controlled within 30 percent, the total processing rate of stretching is 64 percent, and the finished product is obtained by sizing and sawing after stretching

Finished bar

Example 3

2) Casting: and (4) adopting a horizontal continuous casting mode to cast a blank. Wherein the traction speed is 0.3m/min, the traction pitch is 2mm, the reverse thrust length: 0.2mm, cooling water pressure: 0.6Mpa, cooling water inlet temperature: 18-25 ℃, water outlet temperature: 25-35 ℃, and controlling the casting temperature at 1200 ℃. The traction blank specification is as follows:

3) homogenizing and annealing: placing the blank in a well type furnace for homogenizing annealing treatment, wherein the annealing temperature is as follows: the temperature is 700 ℃, and the heat preservation time is 8 h. And quenching the homogenized blank after the heat preservation time is reached, and controlling the water inlet time after the homogenized blank is discharged from the furnace within 30 s.

And (5) coiling a round bar blank.

And (5) coiling a round bar blank.

7) Intermediate low-temperature annealing: and (3) placing the stretched hard blank in a pit furnace for annealing treatment, wherein the annealing temperature is as follows: keeping the temperature for 5h at 440 ℃.

8) And (3) finished product stretching: and (4) pickling the blank subjected to intermediate low-temperature annealing, and then placing the blank in a drawing machine for drawing and straightening. The finished product is stretched in 4 passes, the processing rate of each pass is controlled within 30 percent, the total processing rate of stretching is 63 percent, and the finished product is obtained by sizing and sawing after stretching

Finished bar

9) Stress relief annealing: and (4) placing the finished bar material subjected to fixed-length saw cutting into a box-type furnace for stress relief annealing, and using an ammonia decomposition atmosphere to protect the annealing mode. The heating speed is 10 ℃/min, the heat preservation temperature is 180 ℃, and the heat preservation time is 10 h.

Example 4

1) Smelting: proportioning according to the component requirements, sequentially adding an electrolytic plate, a tin ingot, metal indium and a nickel ingot into an intermediate frequency furnace, heating, controlling the initial temperature to be 1230 ℃, adding a slag removing agent after the raw materials are completely melted, uniformly stirring for 4min, adding a copper-phosphorus alloy, controlling the smelting temperature to be 1200 ℃, and uniformly stirring the melt. And (4) sampling and testing, transferring to a heat preservation furnace after the components are tested to be qualified, adding charcoal to cover, and covering with the thickness of 50 mm.

2) Casting: and (4) adopting a horizontal continuous casting mode to cast a blank. Wherein the traction speed is 0.4m/min, the traction pitch is 2mm, the reverse-thrust length: 0.2mm, cooling water pressure: 0.6Mpa, cooling water inlet temperature: 20-25 ℃, water outlet temperature: 25-35 ℃, and controlling the casting temperature at 1200 ℃. The traction blank specification is as follows:

3) homogenizing and annealing: placing the blank in a well type furnace for homogenizing annealing treatment, wherein the annealing temperature is as follows: the temperature is 710 ℃, and the heat preservation time is 8 h. And quenching the homogenized blank after the heat preservation time is reached, and controlling the water inlet time after the homogenized blank is discharged from the furnace within 30 s.

4) First stretching: placing the blank after the homogenizing annealing in an inverted disc drawing machine for drawing after acid washing treatment, wherein the total processing rate of the first drawing is 20%, and peeling treatment is carried out after the drawing is finished, wherein the peeling amount is 0.5mm, thus obtaining the product

And (5) coiling a round bar blank.

5) Intermediate high-temperature annealing: placing the stretched hard blank in a pit furnace for annealing treatment, wherein the annealing temperature is as follows: keeping the temperature at 540 ℃ for 3 h.

6) And (3) second stretching: pickling the blank subjected to intermediate high-temperature annealing, placing the blank in an inverted disc drawing machine for drawing, wherein the total processing rate of the second drawing is 54 percent, and obtaining the alloy

And (5) coiling a round bar blank.

7) Intermediate low-temperature annealing: and (3) placing the stretched hard blank in a pit furnace for annealing treatment, wherein the annealing temperature is as follows: keeping the temperature for 5h at 420 ℃.

8) And (3) finished product stretching: and (4) pickling the blank subjected to intermediate low-temperature annealing, and then placing the blank in a drawing machine for drawing and straightening. The finished product is stretched in 4 passes, the processing rate of each pass is controlled within 30 percent, the total processing rate of stretching is 58 percent, and the finished product is obtained by sizing and sawing after stretching

Finished bar

Comparative examples are C5240 and Cu-Sn-Zn-Pb alloys.

The obtained examples and comparative examples were subjected to mechanical property and/or microstructure detection, and specific detection indexes and detection standards were as follows:

1) hardness HV 5: GB/T4340.1-2009 Metal materials Vickers hardness test part 1: test methods.

2) Tensile strength and elongation: part 1 of the GB/T228.1-2010 metallic Material tensile test: room temperature tensile test method.

3) And (3) metallographic microscopic test: YS/T449-2002 copper and copper alloy casting and processing product microstructure inspection method.

4) And (3) softening temperature test: GB/T33370-2016 copper and copper alloy softening temperature.

5) Cutting index: the cutting index of C36000(HPb63-3) is set as 100 percent according to the evaluation of the cutting performance detection method in appendix B of YS-T647-2007 copper zinc bismuth tellurium alloy bar.

6) Conductivity: GB/T351-2019 metal material resistivity measurement method.

Table 1 example and comparative example ingredients/wt%

TABLE 2 examples intermediate stage Performance and microstructure

TABLE 3 microstructural properties of the finished bars of the examples and comparative examples

TABLE 4 properties of the finished bars of the examples and comparative examples

Claims

1. A tin-phosphor bronze alloy characterized by: the tin-phosphor bronze alloy comprises the following components in percentage by mass: 8.0-10.0%; p: 0.05-0.2%; in: 0.2-1.0%; ni: 0.05-0.2%; fe: less than or equal to 0.2 percent, and other impurities: less than or equal to 0.2 percent and the balance of Cu.

2. A tin-phosphor bronze alloy according to claim 1, characterized in that: the microstructure of the tin-phosphor bronze alloy contains an In-delta phase, and the average size of the In-delta phase is controlled to be 0.1-2.0 mu m and 1mm ² The number of In-delta phases precipitated per unit area is controlled to be 6000 or more.

3. A tin-phosphor bronze alloy according to any of claims 1 to 2, characterized in that: the tin-phosphor bronze alloy has the tensile strength of more than or equal to 1000MPa, the elongation of more than or equal to 3 percent, the cutting index of more than 70 percent of C36000, the electric conductivity of more than or equal to 15 percent IACS, and the high-temperature softening resistance temperature of more than or equal to 370 ℃.

4. A tin-phosphor bronze alloy according to any of claims 1 to 2, in which: the preparation method comprises the following preparation steps:

1) smelting: proportioning according to the required components;

5. A tin-phosphor bronze alloy according to claim 4, characterized in that: in the step 2), the area ratio of the radial columnar crystal of the obtained blank is controlled to be below 50%.

6. A tin-phosphor bronze alloy according to claim 4, characterized in that: in the step 3), the Sn content deviation of the center and the edge of the annealed blank is controlled within 0.3%, the In-delta phase is granular, and the elongation of the blank reaches more than 70%.

7. A tin-phosphor bronze alloy according to claim 4, characterized in that: in the step 5), the area proportion of the longitudinal strip-shaped processing structure in the annealed blank is reduced to be within 10 percent, the average grain size of the structure is below 30 mu m, and the elongation rate is above 60 percent.

8. A tin-phosphor bronze alloy according to claim 4, characterized in that: in the step 7), the average grain size of the structure after annealing is less than 5 μm, and the elongation can reach more than 50%.

9. A tin-phosphor bronze alloy according to claim 4, characterized in that: in the step 8), the axial and radial residual stress values of the stretched bar are controlled within 200 MPa.

10. A tin-phosphor bronze alloy according to claim 4, characterized in that: in the step 9), the axial and radial residual stress values of the annealed bar are controlled within 80 MPa.