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

Abstract

A method for improving wear resistance of a Cu-Ni-Sn alloy ribbon comprises the steps that a Cu-Ni-Sn alloy ribbon in a solid solution state is put into liquid nitrogen to be soaked, the temperature of the material is reduced to minus 100 DEG C to minus 196 DEG C, the material is rolled, and the reduction rate is 80-95%; and then the thin strip is subjected to age hardening treatment, the treatment temperature ranges from 300 DEG C to 350 DEG C, the treatment time ranges from 0.5 h to 2 h, and finally the strength, hardness and abrasion resistance of the material are synchronously improved. According to the Cu-Ni-Sn alloy thin strip prepared through the method, after deep cold rolling pre-deformation and aging treatment, amplitude modulation decomposition occurs, an ordered phase is separated out, the strength, hardness and abrasion resistance are greatly improved, and the service performance of a material is met.

Description

Technical Field

[0001] The invention belongs to the technical field of copper alloy thin strip forming, and in particular relates to a method for improving the wear resistance of a Cu-Ni-Sn alloy thin strip. Background Art

[0002] Cu-Ni-Sn alloy strips are widely used in high-end CNC machine tools, marine engineering equipment, aerospace equipment and other fields due to their excellent strength and elasticity, outstanding wear and corrosion resistance, high thermal stress relaxation resistance, low production cost and pollution-free advantages, which greatly promotes the goal of replacing beryllium bronze. With the increasing complexity of the alloy application environment and the extreme conditions, the demand for alloy wear resistance in various fields continues to increase. Therefore, it has become an inevitable trend to develop innovative processes to significantly enhance the wear resistance of materials.

[0003] Cu-Ni-Sn alloys are a typical high-strength and high-elastic copper alloy strengthened by spinodal decomposition, and are often used in connectors and other connectors. In the traditional production process, Cu-Ni-Sn alloy sheets first need to be solution treated, and then aging treated to undergo spinodal decomposition and ordered phase precipitation, thereby strengthening the alloy and becoming the final product. However, the direct aging alloy has limited improvements in strength, hardness and wear resistance, and requires long aging treatment, which is very energy-consuming and has a high industrialization cost.

[0004] At present, the main methods to solve this problem include room temperature rolling pretreatment and pre-aging of thin strips; these methods can accelerate the aging process to a certain extent, but these methods have certain limitations in improving material properties. Summary of the invention

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

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

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

[0008] The first step is to immerse the solid solution Cu-Ni-Sn alloy ribbon in liquid nitrogen to reduce the temperature of the material to -100°C to -196°C;

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

[0010] Step 3: The rolled thin strip is subjected to aging hardening treatment to achieve simultaneous improvement of material strength and hardness.

[0011] After completing the aging hardening treatment, the obtained thin strip is subjected to a ball-on-disc friction and wear test to detect the wear resistance of the material. The ball-on-disc friction and wear test has a load of 8 to 12 N, a rotation radius of 5 to 8 mm, a sliding speed of 0.1 to 0.3 m / s, and a sliding distance of 800 to 1200 m.

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

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

[0014] In one embodiment, the tensile strength of the aged thin strip is 1000-1300 MPa, the hardness is 340-400 HV, and the wear resistance is 22×10 -4 ~48×10 -4 mm 3 N -1 m -1 .

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

[0016] The Cu-Ni-Sn alloy thin strip prepared by this method, after deep cold rolling pre-deformation and aging, the alloy rapidly decomposes by amplitude modulation and precipitates an ordered phase, so that the strength, hardness and wear resistance of the alloy are significantly improved, meeting the service performance of the material; in addition, the original direct aging treatment required 4 to 24 hours can be greatly shortened to 0.5 to 2 hours, shortening the aging time and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart of the deep cold rolling pre-deformation and aging hardening treatment of the Cu-Ni-Sn alloy of the present invention. (a) is the deep cold rolling pre-deformation of the Cu-Ni-Sn alloy; (b) is the aging hardening treatment; (c) is the ball-disc friction and wear test.

[0018] Figure 2 This is a graph showing changes in tensile strength and hardness of a Cu-Ni-Sn alloy subjected to a deep cold rolling pre-deformation treatment process after aging treatment with aging time in Example 1 of the present invention.

[0019] Figure 3 It is the wear performance of the Cu-Ni-Sn alloy in Example 1 of the present invention, and the wear rate of the sample after deep cold rolling pre-deformation and room temperature rolling pre-deformation at different aging times.

[0020] Figure 4This is the TEM image of the Cu-Ni-Sn alloy aged for 1 hour in Example 1 of the present invention. DETAILED DESCRIPTION

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

[0022] The present invention realizes a method for improving the wear resistance of a Cu-Ni-Sn alloy thin strip. The main purpose is to improve the pretreatment process of the Cu-Ni-Sn alloy, so that spinodal decomposition and precipitation of an ordered phase occur after aging treatment, thereby greatly improving the strength, hardness and wear resistance of the alloy.

[0023] refer to Figure 1 , the present invention mainly comprises the following steps:

[0024] The first step is to immerse the solid solution Cu-Ni-Sn alloy ribbon in liquid nitrogen to reduce the temperature of the material to -100°C to -196°C;

[0025] The second step: deep cold rolling the cooled thin strip to pre-deform it. This process can be achieved by reciprocating rolling, such as Figure 1 As shown in (a);

[0026] The third step: the thin strip after rolling is subjected to aging hardening treatment to achieve simultaneous improvement of material strength and hardness, such as Figure 1 As shown in (b).

[0027] Subsequently, the aging treated thin strip was subjected to a ball-on-disk friction and wear test to detect the wear resistance of the material, such as Figure 1 As shown in (c).

[0028] The main principle of the present invention is to use deep cold deformation in the alloy after solid solution treatment, inhibit dynamic recovery in a low temperature environment, promote dislocation accumulation, create conditions for precipitation during aging, accelerate the spinodal decomposition of Cu-Ni-Sn alloy and the precipitation of ordered phases, enhance dislocation strengthening and precipitation strengthening, thereby achieving a significant improvement in strength, hardness and wear resistance. At the same time, combined with the rolling process with the characteristics of preparing large-size thin plates and continuous production, deep cold rolling pre-deformation is applied to the pretreatment process of Cu-Ni-Sn alloys, achieving a dual improvement in alloy performance and production efficiency.

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

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

[0031] The first step is to use a Cu-6Ni-6Sn alloy strip in a solid solution state and immerse it in liquid nitrogen for 8 minutes to uniformly reduce the temperature of the material to -196°C.

[0032] Step 2: rolling the cooled thin strip at a rolling speed of 1 m / min and a reduction rate of 90%.

[0033] Step 3: The cold rolled pre-deformed thin strip is subjected to aging hardening treatment at a temperature of 300°C and an aging treatment time of 1h. After aging hardening treatment, the thin strip reaches the peak aging. At this time, the tensile strength and hardness of the sample are 1004MPa and 343HV respectively. Figure 2 shown.

[0034] Step 4: The cold rolled pre-deformed and aged thin strip was subjected to a ball-disc friction and wear test. The wear test was conducted under a normal load of 10N, a sliding radius of 8mm, a sliding speed of 0.136m / s, and a sliding distance of 1000m. The wear rate after friction and wear is as follows Figure 3 As shown in the figure, when the deformation amount is 90% and the aging time is 1h, the wear rate of the deep cold rolled pre-deformed sample is 46.5×10 -4 mm 3 N -1 m -1 As a control, under the same conditions, the ball-disc friction and wear test of the room temperature rolling pre-deformed samples was carried out. It can be found that the wear rate of the room temperature rolling pre-deformed samples is generally higher than that of the deep cold rolling pre-deformed samples. The wear rate of the room temperature rolling pre-deformed sample with aging for 1h is 55.9×10 -4 mm 3 N -1 m -1 , which is higher than the sample subjected to deep cold rolling pre-deformation and aging treatment for 1h, and the gap is the largest, which further reflects the excellent wear resistance of the deep cold rolling pre-deformation sample.

[0035] Step 5: TEM observation of the sample after deep cold rolling pre-deformation and aging treatment for 1h, refer to Figure 4 As shown, a large number of dislocations were found. In addition, spinodal decomposition and precipitation of ordered phases occurred, which further strengthened the alloy and were the key to improving the wear resistance of the sample.

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

[0037] The first step: using a Cu-15Ni-8Sn alloy strip in a solid solution state and immersing it in liquid nitrogen for 8 minutes to uniformly reduce the temperature of the material to -196°C.

[0038] Step 2: rolling the cooled thin strip at a rolling speed of 1 m / min and a reduction rate of 80%.

[0039] Step 3: The thin strip pre-deformed by deep cold rolling is subjected to aging hardening treatment at a temperature of 350°C and an aging treatment time of 1 hour. After aging hardening treatment, the thin strip reaches peak aging.

[0040] Step 4: The thin strip treated by deep cold rolling, pre-deformation and aging was subjected to a ball-disc friction and wear test. The wear test was carried out under a normal load of 10N, a sliding radius of 5mm, a sliding speed of 0.268m / s, and a sliding distance of 1000m. The mechanical properties of the thin strip after aging and the wear rate after friction and wear 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 samples pre-deformed by room temperature rolling are lower than those pre-deformed by deep cold rolling, but the wear rate is higher than that pre-deformed by deep cold rolling, which once again reflects the excellent wear resistance of the samples pre-deformed by deep cold rolling.

Claims

1. A method for improving the wear resistance of a Cu-Ni-Sn alloy strip, characterized in that: The steps include: The first step is to immerse the solid solution Cu-Ni-Sn alloy ribbon in liquid nitrogen to reduce the temperature of the material to -100°C to -196°C; Step 2: rolling the cooled thin strip; Step 3: The rolled thin strip is subjected to aging hardening treatment to achieve simultaneous improvement of material strength and hardness.

2. The method for improving the wear resistance of a Cu-Ni-Sn alloy strip according to claim 1, characterized in that: The second step is to roll the cooled thin strip at a rolling speed of 1.0-2.0 m / min and a reduction rate of 80-95%.

3. The method for improving the wear resistance of a Cu-Ni-Sn alloy strip according to claim 1, characterized in that: In the third step, the aging treatment temperature is 300° C. to 350° C., and the aging treatment time is 0.5 h to 2 h.

4. The method for improving the wear resistance of a Cu-Ni-Sn alloy strip according to claim 1, characterized in that: A ball-on-disc friction and wear test was carried out on the thin strip after aging treatment to detect the wear resistance of the material. The ball-on-disc friction and wear test had a load of 8 to 12 N, a rotation radius of 5 to 8 mm, a sliding speed of 0.1 to 0.3 m / s, and a sliding distance of 800 to 1200 m.

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

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