Method for improving wear resistance of Cu-Ni-Sn alloy thin strip

Abstract

A method for improving wear resistance of Cu-Ni-Sn alloy thin strip, the Cu-Ni-Sn alloy strip in solid solution state is soaked in liquid nitrogen, so that the temperature of the material is reduced to-100 DEG C to-196 DEG C, and the material is rolled with a reduction of 80-95%; then the thin strip is subjected to aging hardening treatment, the treatment temperature is between 300 DEG C to 350 DEG C, and the time is 0.5h-2h, so that the strength, hardness and wear resistance of the material are simultaneously improved. The Cu-Ni-Sn alloy thin strip prepared by the method is subjected to deep cold rolling pre-deformation and aging treatment, then the amplitude modulation decomposition occurs, ordered phase is precipitated, and the strength, hardness and wear resistance are greatly improved, so that the service performance of the material is met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of copper alloy thin strip forming, and particularly relates to a method for improving the wear resistance of Cu-Ni-Sn alloy thin strip. BACKGROUND

[0002] The Cu-Ni-Sn alloy thin strip is widely used in the fields of high-grade numerical control machine tools, ocean engineering equipment and aerospace equipment due to its excellent strength and elasticity, outstanding wear resistance and corrosion resistance, high thermal stress relaxation characteristics, low production cost and no pollution advantage, which greatly promotes the goal of replacing beryllium bronze. With the increasing complexity and extreme conditions of the application environment of the alloy, the demand for the wear resistance of the alloy in various fields is continuously improved. Therefore, it has become an inevitable trend to develop innovative processes to significantly enhance the wear resistance of the material.

[0003] The Cu-Ni-Sn alloy is a typical amplitude modulation decomposition reinforced high-strength and high-elasticity copper alloy, which is often used in connectors and other connectors. In the traditional production process, the Cu-Ni-Sn alloy sheet needs to be first solution treated, and then aged to occur amplitude modulation decomposition and ordered phase precipitation, thereby strengthening the alloy to become the final product. However, the strength, hardness and wear resistance of the direct aging alloy are limited, and long-term aging treatment is required, which is very energy-consuming and has high industrialization cost.

[0004] The current methods for solving this problem mainly include room temperature rolling pretreatment and pre-aging of the thin strip; these methods can accelerate the aging process to a certain extent, but these methods have certain limitations in improving the performance of the material. SUMMARY

[0005] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a method for improving the wear resistance of Cu-Ni-Sn alloy thin strip.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0007] A method for improving the wear resistance of Cu-Ni-Sn alloy thin strip, comprising the following steps:

[0008] Step 1: Put the Cu-Ni-Sn alloy thin strip in a solution state into liquid nitrogen for soaking, so that the temperature of the material is reduced to -100℃ to -196℃;

[0009] Step 2: Roll the cooled thin strip;

[0010] Step 3: Perform aging hardening treatment on the rolled thin strip to simultaneously improve the strength and hardness of the material.

[0011] After the aging treatment is completed, ball-on-disc friction and wear experiment is conducted on the obtained thin strip to detect the wear resistance of the material, wherein the ball-on-disc friction and wear experiment load is 8-12N, the rotation radius is 5-8mm, the sliding speed is 0.1-0.3m / s, and the sliding distance is 800-1200m.

[0012] In one embodiment, the cooled thin strip is rolled, and the rolling speed is 1.0-2.0m / min, and the reduction is 80-95%.

[0013] In one embodiment, the rolled thin strip is subjected to aging treatment, and the aging treatment temperature is 300-350℃, and the aging treatment time is 0.5-2h.

[0014] In one embodiment, the tensile strength of the thin strip after aging is 1000-1300MPa, the hardness is 340-400HV, and the wear resistance is 22x10 -4 -48x10 -4 mm 3 N -1 m -1 .

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

[0016] The Cu-Ni-Sn alloy thin strip prepared by the method is rapidly decomposed by amplitude modulation and ordered phase is precipitated after deep cryogenic rolling pre-deformation and aging, so that the strength, hardness and wear resistance of the alloy are significantly improved, and the service performance of the material is met. In addition, the original direct aging treatment time of 4-24h can be greatly shortened to 0.5-2h, the aging time is shortened, and the production efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a Cu-Ni-Sn alloy deep cryogenic rolling pre-deformation and aging hardening process flowchart of the present application. (a) is Cu-Ni-Sn alloy deep cryogenic rolling pre-deformation; (b) is aging hardening treatment; (c) is ball-on-disc friction and wear experiment.

[0018] Figure 2 is a diagram of the change of the tensile strength and hardness of the Cu-Ni-Sn alloy of embodiment 1 of the present application after aging treatment with the change of aging time.

[0019] Figure 3 is the wear resistance of the Cu-Ni-Sn alloy of embodiment 1 of the present application, and the wear rate of the deep cryogenic rolling pre-deformation and room temperature rolling pre-deformation of the sample under different aging times.

[0020] Figure 4is a TEM image of the Cu-Ni-Sn alloy of embodiment 1 aged for 1h. DETAILED DESCRIPTION

[0021] The embodiments of the present application will be described in detail below with reference to the accompanying drawings and examples.

[0022] The present application realizes a method for improving the wear resistance of Cu-Ni-Sn alloy thin strips, the main purpose of which is to improve the Cu-Ni-Sn alloy pretreatment process, so that the amplitude modulation decomposition and ordered phase precipitation occur after the aging treatment, and the strength, hardness and wear resistance of the alloy are greatly improved.

[0023] Reference Figure 1 The present application mainly includes the following steps:

[0024] Step 1: Put the Cu-Ni-Sn alloy thin strip in a solid solution state into liquid nitrogen for soaking, so that the temperature of the material is reduced to -100℃ to -196℃;

[0025] Step 2: Deep cold rolling is performed on the cooled thin strip to pre-deform it, and this process can be realized by reciprocating rolling, as shown in (a) of FIG. 1. Figure 1

[0026] Step 3: Aging hardening treatment is performed on the rolled thin strip to realize synchronous improvement of the strength and hardness of the material, as shown in (b) of FIG. 1. Figure 1

[0027] Subsequently, ball-on-disc friction and wear experiments are performed on the thin strip after the aging treatment to detect the wear resistance of the material, as shown in (c) of FIG. 1. Figure 1

[0028] The main principle of the present application is that after the solid solution treatment of the alloy, deep cold deformation is adopted to inhibit dynamic recovery in a low-temperature environment, promote dislocation accumulation, create conditions for precipitation in the aging process, accelerate the amplitude modulation decomposition and ordered phase precipitation of the Cu-Ni-Sn alloy, and enhance dislocation strengthening and precipitation strengthening, so as to greatly improve the strength, hardness and wear resistance. At the same time, the rolling process combining the characteristics of preparing large-size thin plates and continuous production is applied to the deep cold rolling pre-deformation in the Cu-Ni-Sn alloy pretreatment process, so that the alloy performance and production efficiency are improved.

[0029] The pre-deformation technology is currently suitable for the preparation of Cu-Ni-Sn alloy thin strips, and the strength, hardness and wear resistance of the Cu-Ni-Sn alloy thin strips prepared by using the technology can be significantly improved.

[0030] In one specific embodiment 1 of the present application, deep cold preforming is performed on a Cu-6Ni-6Sn alloy thin strip and then aging treatment is performed, and the steps are as follows: ​​​

[0031] First step: Cu-6Ni-6Sn alloy thin strip in solid solution state is used and soaked in liquid nitrogen for 8 minutes, so that the temperature of the material is uniformly reduced to -196℃.

[0032] Second step: the cooled thin strip is rolled at a rolling speed of 1 m / min and a reduction of 90%.

[0033] Third step: the thin strip pre-deformed by deep cold rolling is subjected to aging hardening treatment at a temperature of 300℃ for 1h. After the aging hardening treatment, the thin strip reaches the peak aging, at which time the tensile strength and hardness of the sample are 1004 MPa and 343 HV respectively, as shown in the reference Figure 2 .

[0034] Fourth step: the thin strip pre-deformed by deep cold rolling and aging treatment is subjected to ball-disk friction and wear test, the wear test is carried out under a normal load of 10N, the sliding radius is 8mm, the sliding speed is 0.136m / s, and the sliding distance is 1000m. The wear rate after friction and wear is shown in the reference Figure 3 , wherein when the deformation is 90% and the aging time is 1h, the wear rate of the pre-deformed sample by deep cold rolling is 46.5×10 -4 mm 3 N -1 m -1 . As a comparison, under the same conditions, the ball-disk friction and wear test of the sample pre-deformed by room temperature rolling is carried out, and it can be found that the wear rate of the sample pre-deformed by room temperature rolling is generally higher than that of the sample pre-deformed by deep cold rolling, wherein the wear rate of the sample pre-deformed by room temperature rolling and aging for 1h is 55.9×10 -4 mm 3 N -1 m -1 , which is higher than that of the sample pre-deformed by deep cold rolling and aging for 1h, and the difference is the largest, further embodying the excellent wear resistance of the sample pre-deformed by deep cold rolling.

[0035] Fifth step: the sample pre-deformed by deep cold rolling and aging for 1h is observed by TEM, as shown in the reference Figure 4 , a large number of dislocations are found, in addition to the occurrence of amplitude modulation decomposition and the precipitation of ordered phase, which further strengthens the alloy and is the key to the improvement of the wear resistance of the sample.

[0036] In one specific embodiment 2 of the present application, Cu-15Ni-8Sn alloy thin strip is pre-formed by deep cold and then subjected to aging treatment, the steps are as follows:

[0037] First step: Cu-15Ni-8Sn alloy thin strip in solid solution state is used and soaked in liquid nitrogen for 8 minutes, so that the temperature of the material is uniformly reduced to -196℃.

[0038] Second step: the cooled thin strip was rolled at a speed of 1 m / min and a reduction of 80%.

[0039] Third step: the cryo-rolled pre-deformed thin strip was aged at a temperature of 350 °C for 1 h. After the aging hardening treatment, the thin strip reached the peak aging.

[0040] Fourth step: the cryo-rolled pre-deformed and aged thin strip was subjected to a ball-on-disc friction and wear test, which was carried out under a normal load of 10 N, a sliding radius of 5 mm, a sliding speed of 0.268 m / s and a sliding distance of 1000 m. The mechanical properties of the aged thin strip and the wear rate after the friction and wear test are shown in Table 1.

[0041] Table 1

[0042]

[0043] According to Table 1, it is not difficult to find that the strength and hardness of the room-temperature-rolled pre-deformed sample are lower than those of the cryo-rolled pre-deformed sample, while the wear rate is higher than that of the cryo-rolled pre-deformed sample, which again reflects the excellent wear resistance of the cryo-rolled pre-deformed sample.

Claims

1. A method for improving the wear resistance of Cu-Ni-Sn alloy thin strips, characterized in that, Includes the following steps: Step 1: Immerse the solid solution Cu-Ni-Sn alloy strip in liquid nitrogen to lower the temperature of the material to -100℃ to -196℃; The second step is to roll the cooled strip at a speed of 1.0 to 2.0 m / min and a reduction rate of 80-95%. The third step is to perform an aging hardening treatment on the rolled strip to simultaneously improve the material strength and hardness, and to achieve peak aging of the strip. The aging treatment temperature is 300℃~350℃ and the aging treatment time is 0.5h-2h.

2. The method for improving the wear resistance of Cu-Ni-Sn alloy thin strips according to claim 1, characterized in that, Ball-disc friction and wear test was conducted on the aged strip to test the wear resistance of the material. The ball-disc friction and wear test load was 8-12 N, the rotation radius was 5-8 mm, the sliding speed was 0.1-0.3 m / s, and the sliding distance was 800-1200 m.

3. The method for improving the wear resistance of Cu-Ni-Sn alloy thin strips according to claim 2, characterized in that, After aging, the tensile strength of the thin strip is 1000-1300 MPa, the hardness is 340-400 HV, and the wear resistance is 22×10⁻⁶. -4 ~48×10 -4 mm 3 N -1 m -1 .

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