Preparation method of microalloyed wear-resistant and corrosion-resistant tin-containing copper alloy

Abstract

The present invention discloses a method for preparing a micro-alloyed wear-resistant and corrosion-resistant tin-containing copper alloy. The method for preparing the tin-containing copper alloy is improved in this scheme. Firstly, the components are improved by adding yttrium, lanthanum, and samarium in combination with other components in specific proportions. Secondly, the annealing stage is improved. The four-stage annealing treatment method combined with the improvement of the components enables the formed copper alloy to achieve a significant improvement in properties such as wear resistance and corrosion resistance.

Description

Technical Field

[0001] The invention relates to the technical field of alloys, and in particular to a method for preparing a micro-alloyed wear-resistant and corrosion-resistant tin-containing copper alloy. Background Art

[0002] Red copper is industrial pure copper. It is rose red in color and turns purple after an oxide film forms on its surface, so it is generally called red copper or red copper. Red copper performs well in properties such as electrical conductivity, so it is widely used in electrical connectors and chemical equipment. The disadvantage is that red copper has poor corrosion resistance and wear resistance. It is prone to corrosion during storage and transportation, and the surface color changes and generates impurities with high resistivity, which affects the conductivity. To this end, improvements to red copper on the market include component improvements and the formation of a surface passivation film. Improvements to components include adding other elements, but the addition of other elements can easily have a great impact on conductivity while improving wear resistance. The formation of a surface passivation film, such as chromate passivation, causes serious chromium ion pollution and needs improvement. Summary of the Invention

[0003] To solve at least one of the above technical deficiencies, the present invention provides the following technical solutions:

[0004] The present application discloses a method for preparing a microalloyed wear-resistant and corrosion-resistant tin-containing copper alloy. The tin-containing copper alloy has the following formula: 100 parts of copper, 0.02-0.06 parts of tin, 0.05-0.08 parts of nickel, 0.001-0.002 parts of sulfur, 0.001-0.002 parts of phosphorus, 0.06-0.08 parts of zinc, 0.03-0.05 parts of yttrium, 0.06-0.08 parts of lanthanum, and 0.04-0.07 parts of samarium.

[0005] The preparation of tin-containing copper alloy comprises the following steps:

[0006] First, copper, tin, nickel, sulfur, phosphorus, zinc, yttrium, lanthanum, and samarium are added to the furnace in proportion and melted;

[0007] Second, casting and forming billets;

[0008] Third, the billet is subjected to stage annealing treatment, including the first stage annealing treatment: heating to 210-215℃, heating time 30-50min, holding time 20-30min; second stage annealing treatment: heating from 210-215℃ to 260-280℃, heating time 20-30min, holding time 40-60min; third stage annealing treatment: heating from 260-280℃ to 360-370℃, heating time 20-30min, holding time 40-60min; fourth stage annealing treatment: heating from 360-370℃ to 470-490℃, heating time 30-50min, holding time 2-2.5h; cooling stage: reducing the temperature to below 100℃ within 4h before unloading.

[0009] The present invention improves the preparation method of tin-containing copper alloy by, firstly, improving the components by adding yttrium, lanthanum, and samarium in combination with other components in specific proportions; secondly, improving the annealing stage. The four-stage annealing treatment method combined with the improvement of the components significantly improves the wear resistance and other properties of the formed copper alloy.

[0010] Furthermore, in the first step, phosphorus, yttrium, lanthanum and samarium are all added in the form of an intermediate alloy.

[0011] Furthermore, the melting temperature in the first step is 1200-1300°C.

[0012] Furthermore, in the second step, after casting, the preform is formed by hot extrusion, such as extrusion at 860-880° C., and then stretched to form the preform.

[0013] Furthermore, corrosion inhibition treatment after the billet is taken out of the furnace helps to improve the corrosion resistance.

[0014] Furthermore, the corrosion inhibition treatment includes the steps of pre-treating the billet with a mixture of oxalic acid and benzotriazole, and secondary treatment with a mixture of hydrogen peroxide and benzotriazole, which can significantly improve the corrosion resistance.

[0015] Furthermore, a temperature of 30-40° C. in the pretreatment step and a temperature of 50-60° C. in the secondary treatment step are conducive to the formation of a passivation film.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention changes the composition of the copper alloy and improves the annealing process accordingly. The addition of rare earth elements in the composition helps to increase the hardness and thus improve the wear resistance. The multi-stage annealing treatment helps to further improve the strength of the alloy to meet the requirements of mechanical properties; the corrosion inhibition treatment helps to improve the corrosion resistance. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to specific embodiments.

[0019] Example 1

[0020] The preparation method of microalloyed wear-resistant and corrosion-resistant tin-containing copper alloy comprises the following steps:

[0021] The formula of the tin-containing copper alloy in this example is as follows: by mass, 100 parts of copper, 0.03 parts of tin, 0.06 parts of nickel, 0.001 parts of sulfur, 0.001 parts of phosphorus, 0.06 parts of zinc, 0.03 parts of yttrium, 0.06 parts of lanthanum, and 0.05 parts of samarium.

[0022] First, copper, tin, nickel, sulfur, phosphorus, zinc, yttrium, lanthanum, and samarium are added to the furnace body in proportion and melted. First, copper materials accounting for 80% of the total copper amount are added to the furnace body and melted at 1250°C. Then zinc, sulfur, nickel, tin, etc. are added in turn. After that, the intermediate alloy formed by the remaining copper materials and phosphorus, yttrium, lanthanum, samarium, etc. is added to the furnace body. The temperature is raised to 1300°C and stirred continuously for 40 minutes. During this process, the slag floating to the surface is removed.

[0023] Second, after cooling to 1210°C, the ingot is cast and then hot extruded to form a billet at a temperature of 870±5°C.

[0024] Third, the billet is subjected to stage annealing treatment, wherein the first stage of annealing treatment is: heating to 210°C, heating time 30 minutes, and holding time 20 minutes.

[0025] Second stage annealing treatment: raise the temperature from 210°C to 260°C, heating time 30min, holding time 40min.

[0026] Three-stage annealing treatment: the temperature is raised from 260°C to 360°C, the heating time is 20 minutes, and the holding time is 45 minutes.

[0027] Four-stage annealing treatment: the temperature is raised from 360°C to 470°C, the heating time is 30 minutes, and the holding time is 2 hours.

[0028] Cooling stage: reduce the temperature to below 100℃ within 4 hours and then take it out of the oven.

[0029] Fourth, after the billet is taken out of the furnace, the billet is subjected to corrosion inhibition treatment. In the pretreatment step, the corrosion inhibition mixture is composed of oxalic acid (4%), benzotriazole (0.03%), and the balance is water. The billet is immersed in the corrosion inhibition mixture for 10 minutes at a temperature of 35°C.

[0030] The corrosion inhibition mixture during the secondary treatment process is composed of hydrogen peroxide (15 ml / L), benzotriazole (0.2%), and the balance being water. The pretreated billet is fished out and immersed in the corrosion inhibition mixture for 15 minutes at a temperature of 55°C.

[0031] Example 2

[0032] The preparation method of microalloyed wear-resistant and corrosion-resistant tin-containing copper alloy comprises the following steps:

[0033] The formula of the tin-containing copper alloy in this example is as follows: by mass, 100 parts of copper, 0.05 parts of tin, 0.08 parts of nickel, 0.002 parts of sulfur, 0.002 parts of phosphorus, 0.08 parts of zinc, 0.05 parts of yttrium, 0.08 parts of lanthanum, and 0.04 parts of samarium.

[0034] First, copper, tin, nickel, sulfur, phosphorus, zinc, yttrium, lanthanum, and samarium are added to the furnace body in proportion and melted. First, copper materials accounting for 80% of the total copper amount are added to the furnace body and melted at 1250°C. Then zinc, sulfur, nickel, tin, etc. are added in turn. After that, the intermediate alloy formed by the remaining copper materials and phosphorus, yttrium, lanthanum, samarium, etc. is added to the furnace body. The temperature is raised to 1300°C and stirred continuously for 50 minutes. During this process, the slag floating to the surface is removed.

[0035] Second, after cooling to 1220°C, the ingot is cast and then hot extruded to form a billet at a temperature of 880°C.

[0036] Third, the billet is subjected to stage annealing treatment, wherein the first stage of annealing treatment is: heating to 215°C, heating time 50 minutes, and holding time 30 minutes.

[0037] Second stage annealing treatment: the temperature is raised from 215°C to 275°C, the heating time is 25 minutes, and the holding time is 60 minutes.

[0038] Three-stage annealing treatment: the temperature is raised from 275°C to 370°C, the heating time is 20 minutes, and the holding time is 45 minutes.

[0039] Four-stage annealing treatment: the temperature is raised from 370°C to 482°C, the heating time is 40 minutes, and the holding time is 2.5 hours.

[0040] Cooling stage: reduce the temperature to below 100℃ within 4 hours and then take it out of the oven.

[0041] Fourth, after the billet is taken out of the furnace, the billet is subjected to corrosion inhibition treatment. In the pretreatment step, the corrosion inhibition mixture is composed of oxalic acid (3%), benzotriazole (0.04%), and the balance is water. The billet is immersed in the corrosion inhibition mixture for 10 minutes at a temperature of 35°C.

[0042] The corrosion inhibition mixture during the secondary treatment process is composed of hydrogen peroxide (12 ml / L), benzotriazole (0.3%), and the balance being water. The pretreated billet is fished out and immersed in the corrosion inhibition mixture for 15 minutes at a temperature of 60°C.

[0043] Example 3

[0044] The preparation method of microalloyed wear-resistant and corrosion-resistant tin-containing copper alloy comprises the following steps:

[0045] The formula of the tin-containing copper alloy in this example is as follows: by mass, 100 parts of copper, 0.05 parts of tin, 0.07 parts of nickel, 0.0015 parts of sulfur, 0.0015 parts of phosphorus, 0.07 parts of zinc, 0.04 parts of yttrium, 0.07 parts of lanthanum, and 0.06 parts of samarium.

[0046] First, copper, tin, nickel, sulfur, phosphorus, zinc, yttrium, lanthanum, and samarium are added to the furnace body in proportion and melted. First, copper materials accounting for 80% of the total copper amount are added to the furnace body and melted at 1250°C. Then zinc, sulfur, nickel, tin, etc. are added in turn. After that, the intermediate alloy formed by the remaining copper materials and phosphorus, yttrium, lanthanum, samarium, etc. is added to the furnace body. The temperature is raised to 1300°C and stirred continuously for 45 minutes. During this process, the slag floating to the surface is removed.

[0047] Second, after cooling to 1200°C, the ingot is cast and then hot extruded to form a billet at a temperature of 875±5°C.

[0048] Third, the billet is subjected to stage annealing treatment, wherein the first stage of annealing treatment is: heating to 213°C, heating time 40 minutes, and holding time 25 minutes.

[0049] Second stage annealing treatment: raise the temperature from 213°C to 270°C, with a heating time of 25 minutes and a holding time of 50 minutes.

[0050] Three-stage annealing treatment: the temperature is raised from 270°C to 365°C, the heating time is 25 minutes, and the holding time is 50 minutes.

[0051] Four-stage annealing treatment: the temperature is raised from 365°C to 480°C, the heating time is 25 minutes, and the holding time is 2.3 hours.

[0052] Cooling stage: reduce the temperature to below 100℃ within 4 hours and then take it out of the oven.

[0053] Fourth, after the billet is taken out of the furnace, the billet is subjected to corrosion inhibition treatment. In the pretreatment step, the corrosion inhibition mixture is composed of oxalic acid (5%), benzotriazole (0.04%), and the balance is water. The billet is immersed in the corrosion inhibition mixture for 10 minutes at a temperature of 30°C.

[0054] The corrosion inhibition mixture during the secondary treatment process is composed of hydrogen peroxide (10 ml / L), benzotriazole (0.3%), and the balance being water. The pretreated billet is fished out and immersed in the corrosion inhibition mixture for 15 minutes at a temperature of 50°C.

[0055] Comparative Example 1

[0056] Compared with Example 3, there is no corrosion inhibition treatment step in this example.

[0057] The mechanical properties of the prepared billet were tested, as shown in Table 1:

[0058] Table 1

[0059] Tensile strength (MPa) High temperature hardness (HV) Example 1 272.8 88.9 Example 2 280.5 90.4 Example 3 278.6 89.5 Comparative Example 1 278.6 89.5

[0060] The billets prepared above were subjected to a hanging test in the atmosphere to evaluate their corrosion resistance by color change, as well as salt water immersion and thermal oxidation tests. The test results are shown in Tables 2, 3, and 4:

[0061] Table 2: Suspension test

[0062]

[0063] Table 3: Salt water immersion test

[0064]

[0065]

[0066] Table 4: Thermal oxidation test

[0067]

[0068] Note: In the above table, 0 represents a bright surface with no color change, 1 represents slight color change, 2 represents significant color change, and 3 represents severe color change.

[0069] It can be seen from the above table that the tin-containing copper alloy prepared in this solution has excellent wear resistance and corrosion resistance, and according to measurements, the copper alloy has a very small decrease in conductivity, about 3%, which is acceptable.

[0070] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that improvements and modifications that do not depart from the principles of the present invention are within the scope of protection of the present invention.

Claims

1. A method for preparing a microalloyed wear-resistant and corrosion-resistant tin-containing copper alloy, characterized in that: The formula of the tin-containing copper alloy is as follows: 100 parts of copper, 0.02-0.06 parts of tin, 0.05-0.08 parts of nickel, 0.001-0.002 parts of sulfur, 0.001-0.002 parts of phosphorus, 0.06-0.08 parts of zinc, 0.03-0.05 parts of yttrium, 0.06-0.08 parts of lanthanum, and 0.04-0.07 parts of samarium; The preparation of tin-containing copper alloy comprises the following steps: First, copper, tin, nickel, sulfur, phosphorus, zinc, yttrium, lanthanum, and samarium are added to the furnace in proportion and melted; Second, casting and forming billets; Third, the billet is subjected to stage annealing treatment, including the first stage annealing treatment: heating to 210-215℃, heating time 30-50min, holding time 20-30min; second stage annealing treatment: heating from 210-215℃ to 260-280℃, heating time 20-30min, holding time 40-60min; third stage annealing treatment: heating from 260-280℃ to 360-370℃, heating time 20-30min, holding time 40-60min; fourth stage annealing treatment: heating from 360-370℃ to 470-490℃, heating time 30-50min, holding time 2-2.5h; cooling stage: reducing the temperature to below 100℃ within 4h before unloading.

2. The method for preparing a microalloyed wear-resistant and corrosion-resistant tin-containing copper alloy according to claim 1, wherein: In the first step, phosphorus, yttrium, lanthanum and samarium are added in the form of master alloys.

3. The method for preparing a microalloyed wear-resistant and corrosion-resistant tin-containing copper alloy according to claim 1, wherein: The melting temperature in the first step is 1200-1300°C.

4. The method for preparing a microalloyed wear-resistant and corrosion-resistant tin-containing copper alloy according to claim 1, wherein: In the second step, the billet is formed by hot extrusion after casting.

5. The method for preparing a microalloyed wear-resistant and corrosion-resistant tin-containing copper alloy according to claim 1, wherein: After the billet is taken out of the furnace, corrosion inhibition treatment is performed.

6. The method for preparing a microalloyed wear-resistant and corrosion-resistant tin-containing copper alloy according to claim 5, wherein: The corrosion inhibition treatment includes the steps of pre-treating the billet with a mixed solution of oxalic acid and benzotriazole, and secondary treatment with a mixed solution of hydrogen peroxide and benzotriazole.

7. The method for preparing a microalloyed wear-resistant and corrosion-resistant tin-containing copper alloy according to claim 6, wherein: The temperature was 30-40°C in the pre-treatment step and 50-60°C in the secondary treatment step.

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