High-strength and high-conductivity iron bronze alloy for electric connector and preparation method of high-strength and high-conductivity iron bronze alloy

Abstract

The invention relates to the technical field of iron bronze alloys, in particular to a high-strength and high-conductivity iron bronze alloy for an electric connector and a preparation method of the high-strength and high-conductivity iron bronze alloy. Zn: 0.05 to 0.5 wt%; ni: 0.05 to 0.5 wt%; si: 0.12 to 0.58 wt%; 0.01 wt% to 0.05 wt% of P; 0.13 wt% to 0.36 wt% of La; 0.22 wt% to 0.51 wt% of Sc; and the balance of Cu. Compared with the prior art, the tensile strength, the conductivity and the hardness of the obtained iron bronze alloy are greatly improved, the high strength can be achieved while the high conductivity performance is kept, and the iron bronze alloy can be applied to electric connector production on a large scale.

Description

Technical Field

[0001] The present invention relates to the technical field of iron bronze alloys, and in particular to a high-strength and high-conductivity iron bronze alloy for an electrical connector and a preparation method thereof. Background Art

[0002] Iron bronze is bronze with iron as the main element. The copper-iron alloy (iron bronze) represented by C19400 alloy. Due to the precipitation of iron during heat treatment, the strength and heat resistance of the alloy are improved. The tensile strength in the hard state can reach 415-485MPa, and the electrical conductivity can reach 60% IACS. It is widely used in contact springs, electrical fixtures, terminals, washers, plugs, screws, etc.

[0003] For example, CN114990377B discloses a high-strength and high-conductivity iron-bronze alloy for electrical connectors, wherein the alloy includes the following components in mass ratio: Fe2.18-2.22%, Zn0.8-0.11%, P0.024-0.026%, Mg0.006-0.008%, Cr0.004-0.006%, La0.001-0.0014%, Ce0.002-0.0022%, and the remainder is Cu. The application has explored the matching ratio of iron, zinc, phosphorus, etc. with magnesium, chromium and rare earth elements through a large number of experiments. Under this component ratio relationship, the tensile strength and electrical conductivity of the iron-bronze alloy are greatly improved by combining the processing steps of hot rolling ingot casting, solution treatment, secondary aging and tertiary cold rolling.

[0004] However, the strength of the above-mentioned iron-bronze alloys still needs to be improved. Therefore, there is an urgent need for iron-bronze alloys that have both high conductivity and high strength. Summary of the invention

[0005] The purpose of the present invention is to overcome the poor strength and conductivity of the iron bronze alloy in the above-mentioned prior art and to propose a high-strength and high-conductivity iron bronze alloy for electrical connectors and a preparation method thereof.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The first aspect of the present invention provides a high-strength and high-conductivity iron bronze alloy for an electrical connector, comprising the following components in mass ratio: Fe: 2.08-3.12wt%; Zn: 0.05-0.5wt%; Ni: 0.05-0.5wt%; Si: 0.12-0.58wt%; P: 0.01-0.05wt%; La: 0.13-0.36wt%; Sc: 0.22-0.51wt%; and the balance is Cu.

[0008] Preferably, the alloy comprises the following components in mass ratio: Fe: 2.38-3.02wt%; Zn: 0.15-0.45wt%; Ni: 0.15-0.45wt%; Si: 0.23-0.51wt%; P: 0.02-0.05wt%; La: 0.19-0.31wt%; Sc: 0.28-0.51wt%; and the balance is Cu.

[0009] The second aspect of the present invention provides a method for preparing the high-strength and high-conductivity iron bronze alloy for the electrical connector, comprising the following steps:

[0010] S1, weigh pure copper, pure iron, pure zinc, pure nickel, pure silicon, pure phosphorus, pure lanthanum and pure scandium according to the composition of the high-strength and high-conductivity iron bronze alloy for use;

[0011] S2, adding pure copper into a resistance furnace for alloy smelting, adding the remaining components after the pure copper is completely melted, stirring, and then refining and degassing while continuously stirring, and obtaining an alloy ingot after slag removal and pouring;

[0012] S3, then heat-treating the alloy ingot in a muffle furnace, and then hot-rolling the alloy ingot after cooling to obtain an alloy hot-rolled plate, and then subjecting the alloy hot-rolled plate to a solid solution treatment and room temperature water quenching to obtain a high-strength and high-conductivity iron bronze alloy.

[0013] Preferably, in step S1, sandpaper is used to remove the oxide layer on the metal surface before weighing.

[0014] Preferably, in step S2, the alloy is smelted at a temperature of 1200-1600°C.

[0015] Preferably, in step S2, the refining time is 10-30 min.

[0016] Preferably, in step S2, the alloy ingot obtained is 70 mm×25 mm×10 mm.

[0017] Preferably, in step S3, the heat treatment conditions are:

[0018] The heating rate is 5-10℃ / min, the temperature is raised to 800℃-1000℃ and kept for 12-20h, and then cooled naturally.

[0019] Preferably, in step S3, the hot rolling conditions are:

[0020] Keep warm at 1000-1200℃ for 1-3h and hot roll to 5mm. The rolling direction is the length direction of the plate and the pressing amount of a single pass is 0.1-0.2mm.

[0021] Preferably, in step S3, the conditions for the solution treatment are:

[0022] The temperature is 1000-1200℃ and the time is 1-2h.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. Compared with the prior art, the iron bronze in the present invention combines the electrical conductivity, thermal conductivity and ductility of copper with the hardness and wear resistance of iron, so that the alloy has good mechanical properties. In addition, phosphorus has a solid solution strengthening effect on iron. When phosphorus is dissolved in the alloy, the phosphorus atoms will cause the queue distortion in the iron matrix, making it difficult for the iron atoms to move under external force. Therefore, when casting the iron bronze alloy, the strength can be significantly improved without reducing the plasticity. In addition, phosphorus can form a eutectic with iron at 1050°C, further enhancing the mechanical properties of the iron-copper alloy.

[0025] The addition of lanthanum and scandium in the present invention can significantly improve the strength and electrical conductivity of the iron bronze alloy. On the one hand, the addition of lanthanum and scandium will induce the formation of Ni2Si and ZnSi2 precipitation, wherein nickel silicide can be used as a dispersed strengthening phase in the iron bronze to hinder dislocation movement, thereby improving the strength of the iron bronze. At the same time, the precipitation of nickel silicide helps to refine the grains of the iron bronze, and further improves the strength of the alloy through the fine grain strengthening mechanism. In addition, nickel silicide is similar to elemental nickel and has good electrical conductivity. When it is dispersed in the iron bronze, it also enhances the electrical conductivity of the iron bronze. The precipitation of zinc silicide can improve Alloy properties. On the one hand, zinc silicide can purify the iron bronze matrix, remove impurities, and indirectly improve the conductivity of iron bronze; on the other hand, the precipitated phase of lanthanum has high conductivity and can promote the formation of high-density twins in the copper matrix, which greatly improves the strength and conductivity of the iron bronze alloy. At the same time, the ScCu4 phase precipitated by scandium has excellent mechanical properties, which can significantly improve the strength of iron bronze. The combined addition of lanthanum and scandium is often distributed in vacancies, dislocations, grain boundaries and phase interfaces, which inhibits the movement of dislocations, the rotation of grain boundaries and the coarsening of precipitates, thereby giving the iron bronze alloy excellent strength and conductivity.

[0026] 2. The homogenization heat treatment and hot rolling in the present invention improve the mechanical properties of the iron-bronze alloy. After the heat treatment, the alloy component segregation can be effectively removed, making the alloy component more homogenous. The homogenization heat treatment using a muffle furnace can reduce the amount of coarse phases, thereby significantly improving the segregation of alloy elements near dendrites. In addition, hot rolling can promote the dissolution of coarse phases and the precipitation of nano-scale precipitates. At the same time, hot rolling can effectively eliminate coarse phases near multiple grain boundaries, resulting in significant crack healing and elimination of grain boundary casting defects.

[0027] Figure 1 It is a flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] For ease of understanding of the present application, the present application will be described more fully below by way of embodiments. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0030] For simplicity, the present application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unclearly recorded range; and any lower limit can be combined with other lower limits to form an unclearly recorded range, and any upper limit can be combined with any other upper limit to form an unclearly recorded range. In addition, although not clearly recorded, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unclearly recorded range.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present application. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. It should be noted that, unless otherwise stated, the term "and / or" used herein includes any and all combinations of one or more related listed items, and "above", "below" include the number, and the meaning of "multiple" in "one or more" is more than two.

[0032] Example 1

[0033] Reference Figure 1 As shown, this embodiment provides a method for preparing a high-strength and high-conductivity iron bronze alloy for an electrical connector, comprising the following steps:

[0034] S1. According to the composition of the high-strength and high-conductivity iron-bronze alloy, pure copper, pure iron, pure zinc, pure nickel, pure silicon, pure phosphorus, pure lanthanum and pure scandium are weighed respectively for use, wherein the added metal elements are calculated by weight as follows: Fe: 2.52wt%; Zn: 0.17wt%; Ni: 0.27wt%; Si: 0.38wt%; P: 0.03wt%; La: 0.24wt%; Sc: 0.41wt%; and the balance is Cu.

[0035] S2, adding pure copper into a resistance furnace for alloy smelting at a smelting temperature of 1500°C, adding the remaining components after the pure copper is completely melted, stirring, and then refining and degassing while continuously stirring, the refining time is 20 minutes, and after slag removal and pouring, an alloy ingot is obtained, the alloy ingot is 70 mm long, 25 mm wide, and 10 mm thick;

[0036] S3, then heat the alloy ingot in a muffle furnace at a heating rate of 10°C / min, heating to 900°C and keeping it for 15 hours for heat treatment, naturally cooling after heat treatment, and then hot rolling the alloy ingot after cooling, wherein, firstly, keeping it at 1100°C for 2 hours, and hot rolling to 5mm, the rolling direction is the length direction of the plate, and the single pass pressing amount is 0.15mm, to obtain the alloy hot-rolled plate, and then the alloy hot-rolled plate is subjected to 1100°C / 1h solid solution treatment and room temperature water quenching to obtain a high-strength and high-conductivity iron bronze alloy.

[0037] Example 2

[0038] Reference Figure 1 As shown, this embodiment provides a method for preparing a high-strength and high-conductivity iron bronze alloy for an electrical connector, comprising the following steps:

[0039] S1. According to the composition of the high-strength and high-conductivity iron-bronze alloy, pure copper, pure iron, pure zinc, pure nickel, pure silicon, pure phosphorus, pure lanthanum and pure scandium are weighed respectively for use, wherein the added metal elements are calculated by weight as follows: Fe: 2.49wt%; Zn: 0.20wt%; Ni: 0.30wt%; Si: 0.24wt%; P: 0.03wt%; La: 0.20wt%; Sc: 0.31wt%; and the balance is Cu.

[0040] S2, adding pure copper into a resistance furnace for alloy smelting at a smelting temperature of 1500°C, adding the remaining components after the pure copper is completely melted, stirring, and then refining and degassing while continuously stirring, the refining time is 20 minutes, and after slag removal and pouring, an alloy ingot is obtained, the alloy ingot is 70 mm long, 25 mm wide, and 10 mm thick;

[0041] S3, then heat the alloy ingot in a muffle furnace at a heating rate of 10°C / min, heating to 900°C and keeping it for 15 hours for heat treatment, naturally cooling after heat treatment, and then hot rolling the alloy ingot after cooling, wherein, firstly, keeping it at 1100°C for 2 hours, and hot rolling to 5mm, the rolling direction is the length direction of the plate, and the single pass pressing amount is 0.15mm, to obtain the alloy hot-rolled plate, and then the alloy hot-rolled plate is subjected to 1100°C / 1h solid solution treatment and room temperature water quenching to obtain a high-strength and high-conductivity iron bronze alloy.

[0042] Example 3

[0043] Reference Figure 1As shown, this embodiment provides a method for preparing a high-strength and high-conductivity iron bronze alloy for an electrical connector, comprising the following steps:

[0044] S1. According to the composition of the high-strength and high-conductivity iron-bronze alloy, pure copper, pure iron, pure zinc, pure nickel, pure silicon, pure phosphorus, pure lanthanum and pure scandium are weighed respectively for use, wherein the added metal elements are calculated by weight as follows: Fe: 2.88wt%; Zn: 0.40wt%; Ni: 0.4wt%; Si: 0.41wt%; P: 0.04wt%; La: 0.29wt%; Sc: 0.42wt%; and the balance is Cu.

[0045] S2, adding pure copper into a resistance furnace for alloy smelting at a smelting temperature of 1500°C, adding the remaining components after the pure copper is completely melted, stirring, and then refining and degassing while continuously stirring, the refining time is 20 minutes, and after slag removal and pouring, an alloy ingot is obtained, the alloy ingot is 70 mm long, 25 mm wide, and 10 mm thick;

[0046] S3, then heat the alloy ingot in a muffle furnace at a heating rate of 10°C / min, heating to 900°C and keeping it for 15 hours for heat treatment, naturally cooling after heat treatment, and then hot rolling the alloy ingot after cooling, wherein, firstly, keeping it at 1100°C for 2 hours, and hot rolling to 5mm, the rolling direction is the length direction of the plate, and the single pass pressing amount is 0.15mm, to obtain the alloy hot-rolled plate, and then the alloy hot-rolled plate is subjected to 1100°C / 1h solid solution treatment and room temperature water quenching to obtain a high-strength and high-conductivity iron bronze alloy.

[0047] Example 4

[0048] Reference Figure 1 As shown, this embodiment provides a method for preparing a high-strength and high-conductivity iron bronze alloy for an electrical connector, comprising the following steps:

[0049] S1. According to the composition of the high-strength and high-conductivity iron-bronze alloy, pure copper, pure iron, pure zinc, pure nickel, pure silicon, pure phosphorus, pure lanthanum and pure scandium are weighed respectively for use, wherein the added metal elements are calculated by weight as follows: Fe: 2.49wt%; Zn: 0.20wt%; Ni: 0.30wt%; Si: 0.24wt%; P: 0.03wt%; La: 0.20wt%; Sc: 0.31wt%; and the balance is Cu.

[0050] S2, adding pure copper into a resistance furnace for alloy smelting at a smelting temperature of 1600°C, adding the remaining components after the pure copper is completely melted, stirring, and then refining and degassing while continuously stirring for 30 minutes, and obtaining an alloy ingot after slag removal and pouring, the alloy ingot is 70 mm long, 25 mm wide, and 10 mm thick;

[0051] S3, then heat the alloy ingot in a muffle furnace at a heating rate of 10°C / min, heating to 1000°C and keeping it for 15 hours for heat treatment, naturally cool after heat treatment, and then hot roll the alloy ingot after cooling, wherein, first, keep it at 1200°C for 1 hour, and hot roll it to 5 mm, the rolling direction is the length direction of the plate, and the single pass pressing amount is 0.15 mm, to obtain the alloy hot-rolled plate, and then the alloy hot-rolled plate is subjected to 1200°C / 1h solid solution treatment and room temperature water quenching to obtain a high-strength and high-conductivity iron bronze alloy.

[0052] Example 5

[0053] Reference Figure 1 As shown, this embodiment provides a method for preparing a high-strength and high-conductivity iron bronze alloy for an electrical connector, comprising the following steps:

[0054] S1. According to the composition of the high-strength and high-conductivity iron-bronze alloy, pure copper, pure iron, pure zinc, pure nickel, pure silicon, pure phosphorus, pure lanthanum and pure scandium are weighed respectively for use, wherein the added metal elements are calculated by weight as follows: Fe: 2.49wt%; Zn: 0.20wt%; Ni: 0.30wt%; Si: 0.24wt%; P: 0.03wt%; La: 0.20wt%; Sc: 0.31wt%; and the balance is Cu.

[0055] S2, adding pure copper into a resistance furnace for alloy smelting at a smelting temperature of 1200°C, adding the remaining components after the pure copper is completely melted, stirring, and then refining and degassing while continuously stirring, the refining time is 20 minutes, and after slag removal and pouring, an alloy ingot is obtained, the alloy ingot is 70 mm long, 25 mm wide, and 10 mm thick;

[0056] S3, then heat the alloy ingot in a muffle furnace at a heating rate of 10°C / min, heating to 800°C and keeping it for 15 hours for heat treatment, and naturally cool it after heat treatment. After cooling, the alloy ingot is hot rolled, wherein it is first kept at 1000°C for 3 hours and hot rolled to 5 mm in the rolling direction of the plate length, and the single-pass pressing amount is 0.15 mm to obtain an alloy hot-rolled plate, and then the alloy hot-rolled plate is subjected to 1000°C / 1h solid solution treatment and room temperature water quenching to obtain a high-strength and high-conductivity iron bronze alloy.

[0057] Comparative Example 1

[0058] Compared with Example 1, most of the steps are the same except that silicon is not added.

[0059] Comparative Example 2

[0060] Compared with Example 1, most of the steps are the same except that no lanthanum element is added.

[0061] Comparative Example 3

[0062] Compared with Example 1, most of the steps are the same except that scandium element is not added.

[0063] Comparative Example 4

[0064] Compared with Example 1, most of the steps are the same, except that the lanthanum element is replaced by the cerium element.

[0065] Comparative Example 5

[0066] Compared with Example 1, most of the steps are the same except that no heat treatment is performed.

[0067] Test Case

[0068] The alloys obtained in Examples 1 to 5 and Comparative Examples 1 to 5 were tested for tensile strength, hardness and conductivity using GB / T228.1-2021, GB / T4340.1-2009 and GB / T351-2019, respectively. The obtained performance parameters are detailed in Table 1 below.

[0069] Table 1 Alloy related performance parameters of the embodiments and comparative examples

[0070] Examples Tensile strength MPa Conductivity IACS Hardness Hv Example 1 588.9 88.7 168.3 Example 2 576.8 86.9 166.2 Example 3 597.2 89.2 169.9 Example 4 583.4 88.4 167.8 Example 5 586.2 88.2 167.6 Comparative Example 1 413.3 64.2 145.9 Comparative Example 2 424.9 58.7 148.7 Comparative Example 3 425.8 57.1 147.3 Comparative Example 4 408.4 70.1 143.2 Comparative Example 5 521.7 78.9 158.5

[0071] It can be seen from the above table that the iron bronze alloy obtained by the present invention has greatly improved tensile strength, electrical conductivity and hardness, and can have high strength while maintaining high electrical conductivity, and can be widely used in the production of electrical connectors.

[0072] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A high-strength and high-conductivity iron bronze alloy for electrical connectors, characterized in that: The invention comprises the following components by mass ratio: Fe: 2.08-3.12wt%; Zn: 0.05-0.5wt%; Ni: 0.05-0.5wt%; Si: 0.12-0.58wt%; P: 0.01-0.05wt%; La: 0.13-0.36wt%; Sc: 0.22-0.51wt%; The balance is Cu.

2. The high-strength and high-conductivity iron bronze alloy for electrical connectors according to claim 1, characterized in that: The alloy comprises the following components by mass ratio: Fe: 2.38-3.02wt%; Zn: 0.15-0.45wt%; Ni: 0.15-0.45wt%; Si: 0.23-0.51wt%; P: 0.02-0.05wt%; La: 0.19-0.31wt%; Sc: 0.28-0.51wt%; the balance is Cu.

3. A method for preparing a high-strength and high-conductivity iron bronze alloy for an electrical connector as claimed in claim 1 or 2, characterized in that: The following steps are involved: S1, weigh pure copper, pure iron, pure zinc, pure nickel, pure silicon, pure phosphorus, pure lanthanum and pure scandium according to the composition of the high-strength and high-conductivity iron bronze alloy for use; S2, adding pure copper into a resistance furnace for alloy smelting, adding the remaining components after the pure copper is completely melted, stirring, then refining and degassing while continuously stirring, and obtaining an alloy ingot after slag removal and pouring; S3, then heat-treating the alloy ingot in a muffle furnace, and then hot-rolling the alloy ingot after cooling to obtain an alloy hot-rolled plate, and then subjecting the alloy hot-rolled plate to a solid solution treatment and room temperature water quenching to obtain a high-strength and high-conductivity iron bronze alloy.

4. The method for preparing a high-strength and high-conductivity iron bronze alloy for an electrical connector according to claim 3, characterized in that: In step S1, the oxide layer on the metal surface is removed by sandpaper before weighing.

5. The method for preparing a high-strength and high-conductivity iron bronze alloy for an electrical connector according to claim 3, characterized in that: In step S2, the alloy is smelted at a temperature of 1200-1600°C.

6. The method for preparing a high-strength and high-conductivity iron bronze alloy for an electrical connector according to claim 3, characterized in that: In step S2, the refining time is 10-30 minutes.

7. The method for preparing a high-strength and high-conductivity iron bronze alloy for an electrical connector according to claim 3, characterized in that: In step S2, the alloy ingot obtained is 70 mm×25 mm×10 mm.

8. The method for preparing a high-strength and high-conductivity iron bronze alloy for an electrical connector according to claim 3, characterized in that: In step S3, the heat treatment conditions are: The heating rate is 5-10℃ / min, the temperature is raised to 800℃-1000℃ and kept for 12-20h, and then cooled naturally.

9. The method for preparing a high-strength and high-conductivity iron bronze alloy for an electrical connector according to claim 3, characterized in that: In step S3, the hot rolling conditions are: Keep warm at 1000-1200℃ for 1-3h and hot roll to 5mm. The rolling direction is the length direction of the plate and the pressing amount of a single pass is 0.1-0.2mm.

10. The method for preparing a high-strength and high-conductivity iron bronze alloy for an electrical connector according to claim 3, characterized in that: The conditions of the solution treatment are: The temperature is 1000-1200℃ and the time is 1-2h.

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