Lead-free copper alloy and preparation method thereof

Abstract

The application discloses a lead-free copper alloy and a preparation method thereof. The lead-free copper alloy is mainly made of the following components: copper, sulfur and a calcium-lanthanum-carbon mixture; the sulfur and copper are in a mass ratio of 0.7-1%:1, and the calcium-lanthanum-carbon mixture and copper are in a mass ratio of 0.2-0.5%:1. The lead-free copper alloy has the properties of high conductivity, easy cutting, high resistance to melting and welding and the like, and meets the environmental protection requirements of lead-free and the like.

Description

Technical Field

[0001] The present invention relates to a copper alloy, in particular to a lead-free copper alloy and a preparation method thereof. Background Art

[0002] With the advancement of high-tech industries, high-performance, high-purity new materials are key to the development of high-tech fields. Copper alloys are alloys composed of one or more elements added to pure copper. Their excellent electrical conductivity, thermal conductivity, ductility, and heat resistance have made them indispensable materials for my country's development. Currently, the market generally uses alloys that add at least one of the following elements: lead, tin, magnesium, nickel, and zinc. Lead can improve the cutting performance of copper alloys, but it poses a significant risk to the human body. In addition, due to the special properties of copper alloys, their high strength but poor electrical conductivity results in low production yields of high-performance copper alloys, which cannot meet industrial demand. Therefore, it is of great significance to develop a high-performance copper alloy that maintains the mechanical properties of copper alloys while also being lead-free, highly conductive, high-strength, and having good cutting performance.

[0003] The above background technology is for facilitating understanding of the present invention and is not a known technology disclosed to the general public before the application of the present invention. Summary of the Invention

[0004] In view of the above-mentioned defects, the present invention provides a lead-free copper alloy, which has the properties of high conductivity, easy cutting, high resistance to fusion welding, etc., and meets environmental protection requirements such as lead-free.

[0005] The technical solution is: a lead-free copper alloy, which is mainly made of the following components:

[0006] copper;

[0007] sulfur; and

[0008] calcium-lanthanum-carbon mixture;

[0009] Based on the weight of copper, sulfur: copper = 0.7~1%:1, calcium-lanthanum-carbon mixture: copper = 0.2~0.5%:1.

[0010] Furthermore, the copper is cathode copper, and the sulfur is sulfur powder.

[0011] Furthermore, in the calcium-lanthanum-carbon mixture, the weight ratio of calcium:lanthanum:carbon is 2-3:1-2:5.

[0012] Furthermore, the preparation method of the lead-free copper alloy comprises the following steps:

[0013] S1, smelting: add copper into the furnace and cover it with charcoal or graphite flakes, then heat and melt;

[0014] S2, after the cathode copper is completely melted, the temperature is raised to 1000℃~1200℃, and the calcium-lanthanum-carbon mixture is added to the copper liquid and stirred slowly;

[0015] S3, after standing for 10 minutes to 30 minutes, add sulfur to the copper liquid and stir slowly;

[0016] S4, heat up to 1000℃~1200℃, keep warm, let it stand for 10 minutes to 30 minutes, and then start casting.

[0017] S5, billet extrusion: The cast copper alloy is heated to 700℃~900℃ by industrial frequency and hot extruded, and the extruded billet is water-cooled;

[0018] S6, cold working: cold drawing to finished product using hydraulic drawing machine.

[0019] Furthermore, in S3, the sulfur is wrapped with copper sheets before being put into the copper liquid.

[0020] The present invention also provides a method for preparing the lead-free copper alloy.

[0021] The technical solution is: a method for preparing a lead-free copper alloy, comprising the following steps:

[0022] S1, smelting: add copper into the furnace and cover it with charcoal or graphite flakes, then heat and melt;

[0023] S2, after the cathode copper is completely melted, the temperature is raised to 1000℃~1200℃, and the calcium-lanthanum-carbon mixture is added to the copper liquid and stirred slowly;

[0024] S3, after standing for 10 minutes to 30 minutes, add sulfur to the copper liquid and stir slowly;

[0025] S4, heat up to 1000℃~1200℃, keep warm, let it stand for 10 minutes to 30 minutes, and then start casting.

[0026] S5, billet extrusion: The cast copper alloy is heated to 700℃~900℃ by industrial frequency and hot extruded, and the extruded billet is water-cooled;

[0027] S6, cold working: using hydraulic drawing machine to cold draw to finished product;

[0028] Among them, based on the weight of copper, sulfur: copper = 0.7~1%:1, calcium-lanthanum-carbon mixture: copper = 0.2~0.5%:1.

[0029] Furthermore, the copper is cathode copper, and the sulfur is sulfur powder.

[0030] Furthermore, in the calcium-lanthanum-carbon mixture, the weight ratio of calcium:lanthanum:carbon is 2-3:1-2:5.

[0031] Furthermore, in S3, the sulfur is wrapped with copper sheets before being put into the copper liquid.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention adds sulfur, calcium, lanthanum and carbon to copper liquid, and under the synergistic effect, deoxidizes, removes impurities, refines grains, purifies grain boundaries, stabilizes grain size and improves fluidity during the copper smelting process, thereby improving the cutting performance, anti-welding performance and electrical conductivity of copper. DETAILED DESCRIPTION

[0034] The present invention will be further described below.

[0035] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0036] The following specific embodiments are used to describe the technical solution of the present invention in detail. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0037] Example 1

[0038] S1, smelting: add cathode copper into the furnace and cover it with charcoal or graphite flakes, then heat up and melt it.

[0039] S2. After the cathode copper is completely melted, the temperature is raised to 1100°C, and a calcium-lanthanum-carbon mixture (calcium: lanthanum: carbon weight ratio of 2:2:5) is added to the copper liquid at a rate of 0.35% of the weight of the cathode copper, and the mixture is slowly stirred for 2 minutes.

[0040] S3, after standing for 15 minutes, add sulfur powder into the copper liquid at a rate of 0.85% of the weight of the cathode copper (wrap the sulfur powder with copper foil before adding it) and stir slowly for 2 minutes.

[0041] S4, heat up to 1200℃, keep warm, let stand for 20 minutes, and then start casting.

[0042] S5, billet extrusion: The copper alloy formed by casting is heated to 800°C by industrial frequency and hot extruded, and the extruded billet is water-cooled.

[0043] S6, cold working: cold drawing to finished product using hydraulic drawing machine.

[0044] Example 2

[0045] S1, smelting: add cathode copper into the furnace and cover it with charcoal or graphite flakes, then heat up and melt it.

[0046] S2. After the cathode copper is completely melted, heat it to 1100℃, add sulfur powder according to the weight of the cathode copper into the copper liquid (wrap the sulfur powder with copper foil before adding it), and stir slowly for 2 minutes.

[0047] S3. After standing for 15 minutes, add a calcium-lanthanum-carbon mixture (calcium:lanthanum:carbon weight ratio of 2:2:5) to the copper solution at a rate of 0.35% of the weight of the cathode copper, and slowly stir for 2 minutes.

[0048] S4, heat up to 1200℃, keep warm, let stand for 20 minutes, and then start casting.

[0049] S5, billet extrusion: The copper alloy formed by casting is heated to 800°C by industrial frequency and hot extruded, and the extruded billet is water-cooled.

[0050] S6, cold working: cold drawing to finished product using hydraulic drawing machine.

[0051] Example 3

[0052] S1, smelting: add cathode copper into the furnace and cover it with charcoal or graphite flakes, then heat up and melt it.

[0053] S2. After the cathode copper is completely melted, heat it to 1100℃, add sulfur powder according to the weight of the cathode copper into the copper liquid, and stir slowly for 2 minutes.

[0054] S3. After standing for 15 minutes, add a calcium-lanthanum-carbon mixture (calcium:lanthanum:carbon weight ratio of 2:2:5) to the copper solution at a rate of 0.35% of the weight of the cathode copper, and slowly stir for 2 minutes.

[0055] S4, heat up to 1200℃, keep warm, let stand for 20 minutes, and then start casting.

[0056] S5, billet extrusion: The copper alloy formed by casting is heated to 800°C by industrial frequency and hot extruded, and the extruded billet is water-cooled.

[0057] S6, cold working: cold drawing to finished product using hydraulic drawing machine.

[0058] Example 4

[0059] S1, smelting: add cathode copper into the furnace and cover it with charcoal or graphite flakes, then heat up and melt it.

[0060] S2. After the cathode copper is completely melted, the temperature is raised to 1100°C, and a calcium-lanthanum-carbon mixture (calcium: lanthanum: carbon weight ratio of 2:2:5) is added to the copper liquid at a rate of 0.2% of the weight of the cathode copper, and the mixture is slowly stirred for 2 minutes.

[0061] S3, after standing for 15 minutes, add sulfur powder into the copper liquid at a rate of 0.85% of the weight of the cathode copper (wrap the sulfur powder with copper foil before adding it) and stir slowly for 2 minutes.

[0062] S4, heat up to 1200℃, keep warm, let stand for 20 minutes, and then start casting.

[0063] S5, billet extrusion: The copper alloy formed by casting is heated to 800°C by industrial frequency and hot extruded, and the extruded billet is water-cooled.

[0064] Example 5

[0065] S1, smelting: add cathode copper into the furnace and cover it with charcoal or graphite flakes, then heat up and melt it.

[0066] S2. After the cathode copper is completely melted, the temperature is raised to 1100°C, and a calcium-lanthanum-carbon mixture (wherein the weight ratio of calcium:lanthanum:carbon is 2:2:5) is added to the copper liquid at a rate of 0.5% of the weight of the cathode copper, and the mixture is slowly stirred for 2 minutes.

[0067] S3, after standing for 15 minutes, add sulfur powder into the copper liquid at a rate of 0.85% of the weight of the cathode copper (wrap the sulfur powder with copper foil before adding it) and stir slowly for 2 minutes.

[0068] S4, heat up to 1200℃, keep warm, let stand for 20 minutes, and then start casting.

[0069] S5, billet extrusion: The copper alloy formed by casting is heated to 800°C by industrial frequency and hot extruded, and the extruded billet is water-cooled.

[0070] Example 6

[0071] S1, smelting: add cathode copper into the furnace and cover it with charcoal or graphite flakes, then heat up and melt it.

[0072] S2. After the cathode copper is completely melted, the temperature is raised to 1100°C, and a calcium-lanthanum-carbon mixture (wherein the weight ratio of calcium:lanthanum:carbon is 3:1:5) is added to the copper liquid at a rate of 0.35% of the weight of the cathode copper, and the mixture is slowly stirred for 2 minutes.

[0073] S3, after standing for 15 minutes, add sulfur powder into the copper liquid at a rate of 0.85% of the weight of the cathode copper (wrap the sulfur powder with copper foil before adding it) and stir slowly for 2 minutes.

[0074] S4, heat up to 1200℃, keep warm, let stand for 20 minutes, and then start casting.

[0075] S5, billet extrusion: The copper alloy formed by casting is heated to 800°C by industrial frequency and hot extruded, and the extruded billet is water-cooled.

[0076] Comparative Example 1

[0077] S1, smelting: add cathode copper into the furnace and cover it with charcoal or graphite flakes, then heat up and melt it.

[0078] S2. After the cathode copper is completely melted, the temperature is raised to 1100°C, and a magnesium-lanthanum-carbon mixture (magnesium: lanthanum: carbon weight ratio of 2:2:5) is added to the copper liquid at a rate of 0.35% of the weight of the cathode copper, and the mixture is slowly stirred for 2 minutes.

[0079] S3, after standing for 15 minutes, add sulfur powder into the copper liquid at a rate of 0.85% of the weight of the cathode copper (wrap the sulfur powder with copper foil before adding it) and stir slowly for 2 minutes.

[0080] S4, heat up to 1200℃, keep warm, let stand for 20 minutes, and then start casting.

[0081] S5, billet extrusion: The copper alloy formed by casting is heated to 800°C by industrial frequency and hot extruded, and the extruded billet is water-cooled.

[0082] Comparative Example 2

[0083] S1, smelting: add cathode copper into the furnace and cover it with charcoal or graphite flakes, then heat up and melt it.

[0084] S2. After the cathode copper is completely melted, heat it to 1100℃, add sulfur powder into the copper liquid at a rate of 0.85% of the weight of the cathode copper (wrap the sulfur powder with copper foil before adding it), and stir slowly for 2 minutes.

[0085] S4, heat up to 1200℃, keep warm, let stand for 20 minutes, and then start casting.

[0086] S5, billet extrusion: The copper alloy formed by casting is heated to 800°C by industrial frequency and hot extruded, and the extruded billet is water-cooled.

[0087] Comparative Example 3

[0088] S1, smelting: add cathode copper into the furnace and cover it with charcoal or graphite flakes, then heat up and melt it.

[0089] S2. After the cathode copper is completely melted, the temperature is raised to 1100°C, and a calcium-lanthanum-carbon mixture (calcium: lanthanum: carbon weight ratio of 2:2:5) is added to the copper liquid at a rate of 0.35% of the weight of the cathode copper, and the mixture is slowly stirred for 2 minutes.

[0090] S4, heat up to 1200℃, keep warm, let stand for 20 minutes, and then start casting.

[0091] S5, billet extrusion: The copper alloy formed by casting is heated to 800°C by industrial frequency and hot extruded, and the extruded billet is water-cooled.

[0092] Comparative Example 4

[0093] S1, smelting: add cathode copper into the furnace and cover it with charcoal or graphite flakes, then heat up and melt it.

[0094] S2. After the cathode copper is completely melted, the temperature is raised to 1100°C, and a calcium-lanthanum-carbon mixture (calcium: lanthanum: carbon weight ratio is 2:2:5) is added to the copper liquid at a rate of 2% of the weight of the cathode copper, and the mixture is slowly stirred for 2 minutes.

[0095] S3, after standing for 15 minutes, add sulfur powder into the copper liquid at a rate of 0.85% of the weight of the cathode copper (wrap the sulfur powder with copper foil before adding it) and stir slowly for 2 minutes.

[0096] S4, heat up to 1200℃, keep warm, let stand for 20 minutes, and then start casting.

[0097] S5, billet extrusion: The copper alloy formed by casting is heated to 800°C by industrial frequency and hot extruded, and the extruded billet is water-cooled.

[0098] Comparative Example 5

[0099] S1, smelting: add cathode copper into the furnace and cover it with charcoal or graphite flakes, then heat up and melt it.

[0100] S2. After the cathode copper is completely melted, the temperature is raised to 1100°C, and a calcium-lanthanum-carbon mixture (calcium: lanthanum: carbon weight ratio of 2:2:5) is added to the copper liquid at a rate of 0.35% of the weight of the cathode copper, and the mixture is slowly stirred for 2 minutes.

[0101] S3, after standing for 15 minutes, add sulfur powder into the copper liquid at a rate of 0.5% of the weight of the cathode copper (wrap the sulfur powder with copper foil before adding it) and stir slowly for 2 minutes.

[0102] S4, heat up to 1200℃, keep warm, let stand for 20 minutes, and then start casting.

[0103] S5, billet extrusion: The copper alloy formed by casting is heated to 800°C by industrial frequency and hot extruded, and the extruded billet is water-cooled.

[0104] Comparative Example 6

[0105] S1, smelting: add cathode copper into the furnace and cover it with charcoal or graphite flakes, then heat up and melt it.

[0106] S2. After the cathode copper is completely melted, the temperature is raised to 1100°C, and a calcium-lanthanum-carbon mixture (calcium: lanthanum: carbon weight ratio of 2:2:5) is added to the copper liquid at a rate of 0.35% of the weight of the cathode copper, and the mixture is slowly stirred for 2 minutes.

[0107] S3, after standing for 15 minutes, 2% of sulfur powder by weight of the cathode copper was added into the copper liquid (the sulfur powder was wrapped with copper sheet before being added), and slowly stirred for 2 minutes.

[0108] S4, the temperature was raised to 1200℃, and after holding and standing for 20 minutes, casting was started.

[0109] S5, bar extrusion: the copper alloy formed by casting was heated to 800℃ using power frequency, and hot extrusion was performed, and the extruded blank was water cooled.

[0110] Example 7

[0111] The copper alloys prepared in Examples 1-6 and Comparative Examples 1-6 were taken to detect the oxygen content, and the results are shown in Table 1 below.

[0112] The copper alloys prepared in Examples 1-6 and Comparative Examples 1-6 were taken to detect the oxygen content, and the results are shown in Table 1 below.

[0113] Table 1: Oxygen content and performance test results

[0114] From the results in Table 1, when the calcium-lanthanum-carbon ratio is 2:2:5, the weight ratio of the additive is 0.35%, and the weight ratio of the sulfur content is 0.85%, the comprehensive performance is the best, the electrical conductivity is ≥90%, the sulfur content is >0.4%, the machinability is ≥90%, the oxygen content is <10ppm, and the tensile strength is >290Mpa.

[0115] The above description is only preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A lead-free copper alloy, characterized in that The lead-free copper alloy is mainly made of the following components: copper; sulfur; and calcium-lanthanum-carbon mixture; Based on the weight of copper, sulfur: copper = 0.7~1%: 1, calcium-lanthanum-carbon mixture: copper = 0.2~0.5%: 1; Preparation method of the lead-free copper alloy The following steps are involved: S1, smelting: add cathode copper into the furnace and cover it with charcoal or graphite flakes, then heat and melt; S2, after the cathode copper is completely melted, the temperature is raised to 1000℃~1200℃, and the calcium-lanthanum-carbon mixture is added to the copper liquid and stirred slowly; S3, after standing for 10 minutes to 30 minutes, add sulfur powder to the copper liquid and stir slowly; S4, heating to 1000℃~1200℃, keeping warm, standing for 10 minutes to 30 minutes, and then starting casting; S5, billet extrusion: The cast copper alloy is heated to 700℃~900℃ by industrial frequency and hot extruded, and the extruded billet is water-cooled; S6, cold working: using hydraulic drawing machine to cold draw to finished product; In the calcium-lanthanum-carbon mixture, the weight ratio of calcium:lanthanum:carbon is 2-3:1-2:

5.

2. The lead-free copper alloy according to claim 1, characterized in that In S3, the sulfur powder is wrapped with copper sheet before being put into the copper liquid.

3. A method for preparing the lead-free copper alloy according to claim 1, characterized in that: The following steps are involved: S1, smelting: add cathode copper into the furnace and cover it with charcoal or graphite flakes, then heat and melt; S2, after the cathode copper is completely melted, the temperature is raised to 1000℃~1200℃, and the calcium-lanthanum-carbon mixture is added to the copper liquid and stirred slowly; S3, after standing for 10 minutes to 30 minutes, add sulfur powder to the copper liquid and stir slowly; S4, heating to 1000℃~1200℃, keeping warm, standing for 10 minutes to 30 minutes, and then starting casting; S5, billet extrusion: The cast copper alloy is heated to 700℃~900℃ by industrial frequency and hot extruded, and the extruded billet is water-cooled; S6, cold working: using hydraulic drawing machine to cold draw to finished product; Among them, based on the weight of copper, sulfur: copper = 0.7~1%: 1, calcium-lanthanum-carbon mixture: copper = 0.2~0.5%: 1; In the calcium-lanthanum-carbon mixture, the weight ratio of calcium:lanthanum:carbon is 2-3:1-2:

5.

4. The method for preparing a lead-free copper alloy according to claim 3, wherein: In S3, the sulfur powder is wrapped with copper sheet before being put into the copper liquid.

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