High-strength and high-conductivity copper-chromium alloy and short-process manufacturing method

Abstract

The invention provides a high-strength and high-conductivity copper-chromium alloy and a short-process manufacturing method. The high-strength and high-conductivity copper-chromium alloy comprises the following components: 0.2 to 1.0 percent of Cr, 0.05 to 0.30 percent of Ag, 0.01 to 0.20 percent of Ti, 0.01 to 0.20 percent of Si, 0.04 to 0.15 percent of Fe and the balance of copper and inevitable impurities. Compared with the prior art, by adopting the components, the cold rolling machining rate before aging reaches the high machining rate of 90% or above, and the aging treatment temperature timely reaches the temperature required by sufficient precipitation of Cr and the like from a parent phase. According to the method, only one time of aging treatment is carried out after hot rolling, namely cold rolling with the machining rate reaching 90% or above is carried out after hot rolling. And the product is manufactured through final cold rolling and low-temperature treatment, so that the manufacturing process of the product can be shortened. And the tensile strength of the product exceeds 600MPa, and the electric conductivity is greater than 80% IACS.

Description

Technical Field

[0001] The invention belongs to the technical field of copper alloys, and in particular relates to a high-strength and high-conductivity copper-chromium alloy and a short-process manufacturing method. Background Art

[0002] Copper-chromium alloy has high strength and excellent high-temperature stress relaxation properties among copper alloys. Copper-chromium is a typical age-hardening alloy. Through high-temperature solution treatment, a supersaturated solid solution of Cr as a solute atom is formed. And, starting from this state, through a long-term aging treatment at low temperature, nano-scale strengthening phase particles will be precipitated during the process. The strengthening phase particles can strengthen the alloy and make the strength greater than 600MPa; at the same time, the precipitation of Cr elements and the solid solution of Ag elements can improve the electrical conductivity of the alloy.

[0003] With the development of miniaturized and high-density mobile electronic devices represented by smart phones, copper alloy materials used as connectors and other electronic components are also becoming thinner and lighter, requiring higher strength and high conductivity. However, the tensile strength of copper-chromium products currently manufactured is generally between 480 and 550 MPa, or the conductivity is only 70% IACS when the strength reaches 600 MPa, which cannot meet the needs of modern products.

[0004] The patent with publication number CN 112126815 A, published on December 25, 2020, discloses a copper-chromium alloy strip and a preparation method thereof, Cr: 0.2~0.5%, Zr: 0.01~0.1%, Ti: 0.01~0.1%, Si: 0.01~0.1%, and the remainder is Cu and unavoidable impurities; the strip made of copper alloy material has a tensile strength of more than 480MPa and a conductivity of more than 75%IACS. Although the conductivity is improved, the strength is relatively low.

[0005] Copper-chromium alloys, like other copper alloys, have a conflicting relationship between strength and conductivity. Improving strength will impair conductivity, and if conductivity is emphasized, the desired strength will inevitably be reduced.

[0006] Therefore, it is necessary to provide a copper-chromium alloy with high strength and high conductivity. Summary of the invention

[0007] The purpose of the present invention is to provide a high-strength and high-conductivity copper-chromium alloy and a short-process manufacturing method. Through component design, the cold rolling processing rate before aging is controlled to be above 90%. Through aging treatment, a product with a tensile strength of ≥600MPa and a conductivity of ≥80%IACS is produced, and at the same time, it has good thermal conductivity.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0009] A high-strength and high-conductivity copper-chromium alloy comprises the following components in percentage by mass: 0.2-1.0% Cr, 0.05-0.30% Ag, 0.01-0.20% Ti, 0.01-0.20% Si, 0.04-0.15% Fe, and the balance is copper and inevitable impurities.

[0010] Preferably, the Cr content of the high-strength and high-conductivity copper-chromium alloy is 0.3-0.5%.

[0011] If the Cr content does not reach 0.2%, although the conductivity is improved, sufficient strength cannot be obtained. On the contrary, if the Cr content exceeds 1.0% and the content of other elements is too high, the conductivity will decrease. At the same time, due to the formation of coarse precipitates, the bending processability is easily reduced. Considering the strength, conductivity and bending processability, the present invention controls the Cr content to 0.2-1.0%, preferably 0.3-0.5%. At the same time, other trace alloy components are added.

[0012] The content of the unavoidable impurities is not more than 0.10%.

[0013] The high-strength and high-conductivity copper-chromium alloy is a plate or strip material, and the thickness of the high-strength and high-conductivity copper-chromium alloy strip material is less than 0.8 mm.

[0014] The high-strength and high-conductivity copper-chromium alloy has a tensile strength of ≥600 MPa and a conductivity of ≥80% IACS.

[0015] The present invention provides a short-process manufacturing method for a high-strength and high-conductivity copper-chromium alloy, comprising the following steps:

[0016] Smelting → casting → homogenization treatment → hot rolling → cold rolling → aging treatment → final cold rolling → low temperature treatment.

[0017] The homogenization treatment has a heating temperature of 950 to 1050° C. and a heat preservation time of 2 to 12 hours.

[0018] Preferably, when the Cr content in the high-strength and high-conductivity copper-chromium alloy is between 0.3% and 0.5%, the heating temperature during the homogenization treatment is maintained at 960° C. to 1050° C.

[0019] The hot rolling starts at a temperature of 930 to 1030° C. and ends at a temperature of 800° C. or higher. Water cooling is performed after the hot rolling is completed.

[0020] The processing rate of the cold rolling is 90% or more, preferably 92 to 98%.

[0021] The cold rolling uses a reversible cold rolling mill with a diameter of 100 mm to 180 mm. Such a rolling mill can achieve high-pressure rolling of hard materials.

[0022] The aging treatment has a temperature of 300 to 450° C. and a time of 4 to 14 hours.

[0023] The final cold rolling has a processing rate of 30 to 80%.

[0024] The low temperature treatment is specifically: the temperature is 200-360° C. and the time is 4-12 hours.

[0025] Compared with the prior art, the present invention adopts the above composition, and by making the cold rolling processing rate before aging reach a high processing rate of more than 90%, the aging treatment temperature reaches the temperature required for Cr and the like to be fully precipitated from the parent phase in a timely manner. The present invention only performs one aging treatment after hot rolling, that is, cold rolling with a processing rate of more than 90% after hot rolling. The final cold rolling → low temperature treatment is used for manufacturing, thereby shortening the manufacturing process of the product. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1-Example 3

[0028] A high-strength and high-conductivity copper-chromium alloy comprises the following components in percentage by mass: 0.35% Cr, 0.11% Ag, 0.09% Ti, 0.06% Si, 0.09% Fe, and the balance is copper and inevitable impurities.

[0029] Comparative Example 1-Comparative Example 3

[0030] A high-strength and high-conductivity copper-chromium alloy comprises the following components in percentage by mass: 0.35% Cr, 0.11% Ag, 0.09% Ti, 0.06% Si, 0.09% Fe, and the balance is copper and inevitable impurities.

[0031] The copper-chromium alloys in the embodiments and comparative examples have the same composition.

[0032] The short-process manufacturing method of each embodiment comprises the following steps:

[0033] Smelting → casting → homogenization treatment → hot rolling → cold rolling → aging treatment → final cold rolling → low temperature treatment.

[0034] Specifically:

[0035] The homogenization treatment has a heating temperature of 950 to 1050° C. and a heat preservation time of 2 to 12 hours.

[0036] Preferably, when the Cr content in the high-strength and high-conductivity copper-chromium alloy is between 0.3% and 0.5%, the heating temperature during the homogenization treatment is maintained at 960° C. to 1050° C.

[0037] The hot rolling starts at a temperature of 930 to 1030° C. and ends at a temperature of 800° C. or higher. Water cooling is performed after the hot rolling is completed.

[0038] The processing rate of the cold rolling is 90% or more, preferably 92 to 98%.

[0039] The cold rolling uses a reversible cold rolling mill with a diameter of 100 mm to 180 mm. Such a rolling mill can achieve high-pressure rolling of hard materials.

[0040] The aging treatment has a temperature of 300 to 450° C. and a time of 4 to 14 hours.

[0041] The final cold rolling has a processing rate of 30 to 80%.

[0042] The low temperature treatment is specifically 200-360° C. for 4-12 hours.

[0043] The high-strength and high-conductivity copper-chromium alloy is a plate or strip material, and the thickness of the high-strength and high-conductivity copper-chromium alloy strip material is less than 0.8 mm.

[0044] The production process parameters of copper-chromium in each embodiment are shown in Table 1.

[0045] Table 1 Main parameters of the production process of each embodiment

[0046]

[0047] The manufacturing method of the comparative example is as follows:

[0048] Smelting → casting → homogenization treatment → hot rolling → first cold rolling → first aging treatment → second cold rolling → second aging treatment → final cold rolling → low temperature heat treatment.

[0049] The production process parameters of copper chromium in each comparative example are shown in Table 2. Compared with the embodiment, the comparative example has a secondary cold rolling and secondary aging process in the process flow, and the comparative example process is longer.

[0050] Table 2 Main parameters of production process of each comparative example

[0051]

[0052] The performance parameters of the copper-chromium plates produced in various embodiments and comparative examples are shown in Table 3.

[0053] Table 3 Performance of copper-chromium plates produced in various embodiments and comparative examples

[0054]

[0055]

[0056] From the above results, it can be seen that the tensile strength of copper chromium produced in Examples 1-3 exceeds 600 MPa and the conductivity is greater than 80% IACS. The tensile strength of copper chromium produced in Comparative Examples 1-3 is low, less than 600 MPa, and the process is longer than that of the examples.

[0057] The present invention can manufacture copper-chromium plates and strips having higher strength than traditional copper-chromium and better electrical conductivity through a short-process economical manufacturing process that only performs aging once.

[0058] The underlined data above do not meet the requirements of the present invention.

[0059] The description of the above 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 protection scope of the present invention.

Claims

1. A high-strength and high-conductivity copper-chromium alloy, characterized in that: The high-strength and high-conductivity copper-chromium alloy comprises the following components in mass percentage: Cr 0.2-1.0%, Ag 0.05-0.30%, Ti 0.01-0.20%, Si 0.01-0.20%, Fe 0.04-0.15%, and the balance is copper and inevitable impurities.

2. The high-strength and high-conductivity copper-chromium alloy according to claim 1, characterized in that: The high-strength and high-conductivity copper-chromium alloy has a tensile strength of ≥600 MPa and a conductivity of ≥80% IACS.

3. A short-process manufacturing method for a high-strength and high-conductivity copper-chromium alloy according to claim 1 or 2, characterized in that: The manufacturing process comprises the following steps: smelting→casting→homogenization treatment→hot rolling→cold rolling→aging treatment→final cold rolling→low temperature treatment.

4. The manufacturing method according to claim 3, characterized in that: The homogenization treatment has a heating temperature of 950 to 1050° C. and a heat preservation time of 2 to 12 hours.

5. The manufacturing method according to claim 3 or 4, characterized in that: When the Cr content in the high-strength and high-conductivity copper-chromium alloy is between 0.3% and 0.5%, the heating temperature during the homogenization treatment is maintained at 960°C to 1050°C.

6. The manufacturing method according to claim 3, characterized in that: The hot rolling starts at a temperature of 930 to 1030° C. and ends at a temperature of 800° C. or higher. Water cooling is performed after the hot rolling is completed.

7. The manufacturing method according to claim 3, characterized in that: The processing rate of the cold rolling reaches more than 90%.

8. The manufacturing method according to claim 3, characterized in that: The aging treatment has a temperature of 300 to 450° C. and a time of 4 to 14 hours.

9. The manufacturing method according to claim 3, characterized in that: The final cold rolling has a processing rate of 30 to 80%.

10. The manufacturing method according to claim 3, characterized in that: The low temperature treatment is specifically: the temperature is 200-360° C. and the time is 4-12 hours.

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