Process for preparing beryllium bronze

Abstract

The application discloses a beryllium bronze preparation process, which comprises the following steps: first, ultrasonic treatment is performed during the pouring and solidification of a low-beryllium bronze alloy liquid; second, cold deformation processing is performed after vacuum solid solution treatment; and third, aging treatment is performed on the material after the cold deformation processing, including low-temperature aging treatment and high-temperature aging treatment. The low-beryllium bronze alloy prepared by the scheme has achieved a great breakthrough in strength and electrical conductivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of beryllium copper alloys, in particular to a beryllium bronze preparation process. BACKGROUND

[0002] Beryllium bronze (also known as beryllium copper) alloy is a typical age precipitation strengthening type copper alloy, which is widely used in high-end aerospace fields, such as being the preferred material for electrical connectors, and the application environment requires it to have excellent electrical properties and mechanical properties.

[0003] At present, the beryllium bronze developed at home and abroad is mostly high-strength beryllium bronze with a Be content of 1.6-2.0wt.%, which has high strength and hardness but poor electrical conductivity, with an electrical conductivity of ≤30%IACS, which cannot meet the above application requirements. In recent years, due to the increasing environmental protection concept, Be element and its oxides have the characteristics of being toxic and easily polluting the environment, and low beryllium bronze alloys have appeared on the market, which have problems such as: reducing the Be content will cause a significant decrease in strength, and the electrical and thermal conductivity will be significantly improved, and the decrease in strength also cannot meet the above application requirements.

[0004] Therefore, under the premise of reducing the Be content to the maximum extent to meet the basic mechanical properties, how to develop a new type of low-beryllium high-conductivity beryllium bronze alloy with higher electrical conductivity is the current research hotspot, such as the Chinese patent application for invention with the application publication number CN107805733A, which discloses a multi-element high-conductivity beryllium bronze alloy, which is prepared by optimizing the process and components of low-beryllium bronze alloy, and the disadvantage is that the strength and other mechanical properties are sacrificed to improve the electrical conductivity, which is difficult to meet the performance requirements and needs to be improved. SUMMARY

[0005] To solve the above at least one technical defect, the present application provides the following technical scheme:

[0006] The present application discloses a beryllium bronze preparation process, which comprises the following steps:

[0007] First, ultrasonic treatment is performed during the liquid casting and solidification of the low-beryllium bronze alloy;

[0008] Second, cold deformation processing is performed after vacuum solid solution treatment, the deformation amount is 50-70%, the solid solution temperature is 840-875℃, and the residence time in the air after solid solution is ≤6s, and the cooling speed is 660-720℃ / s;

[0009] Third, the material after cold deformation processing is subjected to aging treatment, wherein low-temperature aging treatment at 160-190℃ for 40-60min is performed first, and then high-temperature aging treatment at 300-360℃ for 30-50min is performed.

[0010] The present scheme introduces ultrasonic treatment in the preparation of beryllium copper, and the ultrasonic treatment is performed during the casting and solidification process. The cavitation effect promotes the increase of equiaxed crystals, the obvious refinement of solidification structure, the improvement of macroscopic and microscopic segregation, and the improvement of solvus structure, which lays a foundation for high-temperature solid solution treatment. The beryllium is fully dissolved at the eutectic temperature, and the rapid cooling avoids the precipitation of the beryllium. The large deformation of cold working treatment promotes the formation of vacancies and dislocations in the alloy. The cold deformation and the high and low temperature aging treatment cooperate to accelerate the precipitation of the second phase and increase the precipitation. Therefore, the low beryllium copper alloy prepared in the present scheme has great breakthroughs in strength and electrical conductivity.

[0011] Further, in the first step, the ultrasonic wave of 600-700W and 30-35KHz is introduced to the bottom and sidewall of the ingot mold for treatment. The bidirectional ultrasonic treatment helps to further improve the solidification structure morphology.

[0012] Further, the tool head emitting ultrasonic wave abuts against the sidewall or bottom wall of the ingot mold, and the ultrasonic wave is conducted through the sidewall or bottom wall, which helps to reduce the violent shaking of the metal solution and improve the quality of the solution.

[0013] Further, the time of the vacuum solid solution treatment in the second step is 0.5-2h.

[0014] Further, the components of the low beryllium bronze alloy liquid by mass are as follows: 0.5-0.6% of beryllium, 0.15-0.3% of cobalt, 0.5-0.6% of titanium, 0.1-0.15% of tin, 0.05-0.10% of niobium, and the balance of copper and inevitable impurities. The present scheme optimizes the components of the low beryllium bronze alloy. The low content of beryllium cooperates with the low content of cobalt, titanium, tin and niobium, and the above-mentioned process to make the alloy excellent in strength and electrical conductivity.

[0015] Compared with the prior art, the present application has the following beneficial effects:

[0016] 1. The present application introduces ultrasonic treatment process and cooperates with solid solution, cold working, aging treatment and other processes to make the alloy excellent in strength and electrical conductivity, and is suitable for popularization and application. DETAILED DESCRIPTION

[0017] The present application will be further described below in combination with specific embodiments.

[0018] In the following preparation example of the low beryllium bronze alloy liquid, the required components are added and melted according to the amount, and the melting is performed at 1160℃ for 40min, and then the pouring is performed after the temperature is raised to 1260℃. For the adding form of the components, such as intermediate alloy, the industry common sense can be referred to.

[0019] In the following embodiment, the ultrasonic tool head of 35KHz and 600W is installed at the sidewall and bottom wall of the ingot mold to apply ultrasonic wave for treatment during the solidification process.

[0020] The component mass ratio (%) of the alloy in the following preparation examples is shown in Table 1:

[0021] Table 1

[0022]

[0023] Example 1

[0024] The beryllium bronze preparation process includes the following steps:

[0025] First, the low beryllium bronze alloy liquid with the component ratio shown in Example 1 in Table 1 is poured into an ingot mold, and ultrasonic waves are continuously treated during solidification.

[0026] Second, the solidified ingot in the first step is subjected to vacuum solid solution treatment, the solid solution temperature is 865℃, the time is 1h, and then it is quickly taken out from the solid solution treatment equipment within 5s and placed in a cooling mechanism, the cooling temperature is 680℃ / s;

[0027] After vacuum solid solution treatment, cold deformation processing is carried out, and the deformation amount is 60%.

[0028] Third, the material after cold deformation processing is subjected to aging treatment, wherein the first aging treatment: temperature 170℃, holding time 45min, the second aging treatment: temperature 320℃, holding time 35min.

[0029] Fourth, the alloy material after aging treatment is placed in the air to cool to room temperature.

[0030] Example 2

[0031] The beryllium bronze preparation process includes the following steps:

[0032] First, the low beryllium bronze alloy liquid with the component ratio shown in Example 2 in Table 1 is poured into an ingot mold, and ultrasonic waves are continuously treated during solidification.

[0033] Second, the solidified ingot in the first step is subjected to vacuum solid solution treatment, the solid solution temperature is 870℃, the time is 1h, and then it is quickly taken out from the solid solution treatment equipment within 5s and placed in a cooling mechanism, the cooling temperature is 660℃ / s;

[0034] After vacuum solid solution treatment, cold deformation processing is carried out, and the deformation amount is 70%.

[0035] Third, the material after cold deformation processing is subjected to aging treatment, wherein the first aging treatment: temperature 160℃, holding time 50min, the second aging treatment: temperature 340℃, holding time 30min.

[0036] Fourth, the alloy material after aging treatment is placed in the air to cool to room temperature.

[0037] Comparative Example 1

[0038] Compared with Example 1, in this example, the aging treatment in the preparation process of beryllium bronze adopts a single aging treatment mode, and the aging treatment is carried out at 420℃ for 2h.

[0039] Comparative Example 2

[0040] Compared with Example 1, in this example, the preparation process of beryllium bronze does not have ultrasonic treatment.

[0041] Comparative Example 3

[0042] Compared with Example 1, in this example, the preparation process of beryllium bronze does not have cold deformation processing.

[0043] Comparative Example 4

[0044] Compared with Example 1, in this example, the ultrasonic treatment in the preparation process of beryllium bronze adopts an upper ultrasonic treatment mode, that is, inserting an ultrasonic tool head at the die mouth.

[0045] The alloys prepared in the above examples and comparative examples are detected, and the performance parameters such as tensile strength and electrical conductivity are shown in Table 2:

[0046] Table 2

[0047]

[0048]

[0049] The alloys in the above examples and comparative examples are observed, and it is found that in the examples, after ultrasonic and cold deformation treatment, the dislocations and vacancies increase, the precipitation speed of the second phase increases during the aging treatment process, the precipitates are more, the purity of the copper matrix increases, the electrical conductivity is improved, and the strength is improved. In Comparative Example 1, the alloy has overaging phenomenon under the condition of single temperature and long time aging treatment. In Comparative Example 3, the alloy has underaging phenomenon under the condition of no cold deformation processing and two-pole short-time aging treatment. In Comparative Examples 2 and 4, there are phenomena such as coarse dendrites.

[0050] The above is only a preferred embodiment of the present application, and the protection scope of the present application is not limited to the above examples. Any technical solution falling within the idea of the present application shall fall within the protection scope of the present application. It should be noted that for ordinary technical personnel in the technical field, some improvements and decorations without departing from the principle of the present application shall also be considered as the protection scope of the present application.

Claims

1. A beryllium bronze preparation process, characterized in that, Includes the following steps: First, ultrasonic treatment is used during the casting and solidification process of low-beryllium bronze alloy liquid; Second, after vacuum solution treatment, cold deformation processing is carried out, with a deformation amount of 50-70%, a solution temperature of 840-875℃, and a dwell time in the air after solution treatment of ≤6s, and cooling at a cooling rate of 660-720℃ / s. Third, the materials after cold deformation processing are subjected to aging treatment, which first involves low-temperature aging treatment at 160-190℃ for 40-60 minutes, followed by high-temperature aging treatment at 300-360℃ for 30-50 minutes. In the first step, 600-700W, 30-35KHz ultrasonic waves are introduced into the bottom and sidewalls of the ingot mold for treatment. By weight, the composition of low-beryllium bronze alloy liquid is as follows: 0.5-0.6% beryllium, 0.15-0.3% cobalt, 0.5-0.6% titanium, 0.1-0.15% tin, 0.05-0.10% niobium, with the balance being copper and unavoidable impurities.

2. The beryllium bronze preparation process as described in claim 1, characterized in that: The tool head that emits ultrasonic waves is brought into contact with the side or bottom wall of the ingot mold.

3. The beryllium bronze preparation process as described in claim 1, characterized in that: The vacuum solution treatment in the second step takes 0.5-2 hours.

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