Tin brass alloy strip and preparation method thereof

Abstract

The invention provides a tin brass alloy strip and a preparation method thereof.The preparation method comprises the following steps that a hot-rolled tin brass alloy plate is sequentially subjected to face milling, first-stage rough rolling, intermediate annealing, second-stage finish rolling and final annealing treatment, and the tin brass alloy strip is obtained; wherein the total reduction rate of the first-stage rough rolling is 69-80%, the rolling temperature is room temperature, the total reduction rate of the second-stage finish rolling is 75-83%, and the rolling temperature is room temperature or 250-300 DEG C. According to the method, through precise control over the rolling schedule and combination of the warm rolling process, precise regulation and control over microstructure characteristics such as texture components and grain sizes of the tin brass alloy strip are achieved, and therefore the tensile strength and the bending performance of the tin brass alloy strip are remarkably improved on the premise that no precious alloy element is added, the production cost is reduced, and the production efficiency is improved. And guarantee is provided for the service performance of the tin brass material for the key electric contact device.

Description

Technical Field

[0001] The present invention relates to the technical field of tin-brass alloy preparation, in particular to a tin-brass alloy strip and a preparation method thereof. Background Art

[0002] As modern power electronic equipment evolves toward miniaturization and higher density, the mechanical stress and frequent plugging and unplugging of electrical contact materials during service have significantly increased, placing higher demands on the material's comprehensive mechanical properties. In particular, in key electrical contact devices such as miniature circuit breakers and connectors, the base material must not only maintain excellent electrical and thermal conductivity, but also possess high strength and excellent bending properties. This poses a significant challenge to the performance optimization of traditional tin-brass materials.

[0003] Tin brass (HSn90-1, etc.) is a typical electrical contact substrate. With its good electrical conductivity (≥28% IACS), corrosion resistance and processability, it occupies an important position in the field of low-voltage electrical appliances. However, the HSn90-1 strip prepared by conventional processing technology has significant performance bottlenecks. In particular, the cold-rolled material is prone to form a strong Brass texture and an unfavorable Goss texture, resulting in a sharp decline in the bending performance of the material while achieving higher strength. The current industry generally adopts alloying methods to improve performance by adding trace amounts of precious metal elements such as Ni and Co. Although it can improve strength to a certain extent, every increase of 0.1% of alloying elements will lead to an 8%-12% increase in material costs, and the introduction of excessive alloying elements will deteriorate the material's electrical conductivity and welding reliability.

[0004] Therefore, in response to the above technical difficulties, an invention is proposed to achieve a performance breakthrough through microstructure reconstruction without changing the alloy composition. Summary of the Invention

[0005] The object of the present invention is to provide a tin-brass alloy strip and a preparation method thereof.

[0006] The invention provides the following technical solutions:

[0007] In one aspect, a tin-brass alloy strip is provided, wherein the volume fraction of each texture component in the tin-brass alloy strip is:

[0008] Cube texture 8vol%~14vol%, Copper texture 13vol%~20vol%, Brass texture 7vol%~18vol%, Goss texture 11vol%~18vol%, S texture 21vol%~29vol%.

[0009] On the other hand, a method for preparing a tin-brass alloy strip is provided. The method is used to prepare the above-mentioned tin-brass alloy strip, comprising the following steps:

[0010] The hot-rolled tin-brass alloy sheet is subjected to milling, first-stage rough rolling, intermediate annealing, second-stage finish rolling, and final annealing in sequence to obtain the tin-brass alloy strip;

[0011] The total reduction ratio of the first stage rough rolling is 69% to 80%, and the rolling temperature is room temperature.

[0012] Furthermore, after the tin-brass alloy plate undergoes the first stage rough rolling step, the volume fraction of the Brass texture in the tin-brass alloy plate is 18% to 26%.

[0013] Furthermore, in the intermediate annealing step: the intermediate annealing temperature is 530° C. and the holding time is 2 hours.

[0014] Furthermore, after the tin-brass alloy plate undergoes the intermediate annealing step, the volume fraction of the Brass texture in the tin-brass alloy plate is 12% to 18%.

[0015] Furthermore, in the second stage finishing rolling step:

[0016] The total reduction ratio of the second stage finishing rolling is 75% to 83%, and the rolling temperature is room temperature.

[0017] Furthermore, in the second stage finishing rolling step:

[0018] The total reduction ratio of the second stage finishing rolling is 75% to 83%, and the rolling temperature is 250° C. to 300° C.

[0019] Furthermore, in the step of the final annealing treatment: the holding temperature of the final annealing is 450° C., and the holding time is 3 hours.

[0020] The beneficial effect of this invention is that the present invention can achieve precise regulation of the microstructural characteristics such as the texture composition and grain size of the tin-brass alloy strip through precise control of the rolling schedule combined with the warm rolling process, thereby achieving a significant improvement in the tensile strength and bending performance of the tin-brass alloy strip without adding precious alloy elements, which is beneficial to reducing production costs and providing a guarantee for the service performance of tin-brass materials used in key electrical contact devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 EBSD inverse pole figures of tin-brass alloy strips at different first-stage rough rolling reduction rates;

[0022] Figure 2 The distribution of texture components and average volume fraction of tin-brass alloy strips at different first-stage rough rolling reduction rates are shown in Figure 2.

[0023] Figure 3 EBSD inverse pole figures of tin-brass alloy strip (intermediate annealing state) at different first-stage rough rolling reduction rates;

[0024] Figure 4 The distribution of texture components and average volume fraction of tin brass alloy strip (intermediate annealing state) at different first stage rough rolling reduction rates;

[0025] Figure 5 EBSD inverse pole figures of tin-brass alloy strip (final annealing state) at different second-stage finishing rolling reduction rates;

[0026] Figure 6 The grain size distribution frequency histogram of the tin-brass alloy strip (final annealing state) at different second-stage finishing rolling reduction rates;

[0027] Figure 7 The distribution of texture components and average volume fraction of tin-brass alloy strip (final annealing state) at different second-stage finishing rolling reduction rates;

[0028] Figure 8 The tensile properties of tin-brass alloy strip (final annealing state) at different second-stage finishing rolling reduction rates are shown in Figure 2.

[0029] Figure 9 Bending surface morphology of tin-brass alloy strip (final annealing state) at different second-stage finishing rolling reduction rates; DETAILED DESCRIPTION

[0030] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The drawings illustrate several embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present invention.

[0031] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] First, research has shown that by regulating the proportion and spatial distribution of specific texture components in metal materials, the strength-plasticity contradiction of the material can be effectively coordinated. Based on this, the present invention innovatively proposes a synergistic control strategy for texture engineering and grain boundary engineering: through precise control of the multi-stage rolling schedule, combined with the warm rolling process, the growth of favorable textures such as Cube and Goss in the HSn90-1 tin brass alloy is promoted, while the abnormal growth of unfavorably oriented grains is suppressed. This precise microstructural control method can enable the HSn90-1 tin brass alloy to obtain a uniform equiaxed grain structure with an average grain size of approximately 3μm-5μm, as well as a low Brass texture, S texture, and a high Cube texture and Goss texture ratio, thereby significantly improving the tensile strength and bending performance of the strip, providing an innovative solution for the development of cost-effective electrical contact materials.

[0034] Secondly, the effect of texture on the bending performance of copper alloys is as follows: when the bending axis direction is perpendicular to the rolling direction during the bending process of the copper alloy strip, under the same strain, the presence of Brass texture and S texture makes the copper alloy bending surface prone to wrinkles, and the presence of S texture causes shear bands and stress concentration in the copper alloy bending process; the effect of copper texture on the shear deformation of the copper alloy is relatively weakened, which may cause a small amount of stress concentration on the surface of the specimen; the presence of Goss texture and Cube texture makes the alloy less prone to defects, and Cube texture can effectively inhibit the formation of shear bands and improve the bending performance of the copper alloy. Therefore, from the perspective of copper alloy texture, by reducing the volume fraction of Brass texture, S texture and Copper texture in the current texture component and increasing the volume fraction of Goss texture and Cube texture, it is beneficial to achieve the improvement of the bending performance of copper alloy.

[0035] In summary, the present invention provides the following embodiments:

[0036] Example 1:

[0037] Example 1 provides a method for preparing a tin-brass alloy strip, comprising the following steps:

[0038] The hot-rolled tin-brass alloy sheet is subjected to milling, first-stage rough rolling, intermediate annealing, second-stage finish rolling, and final annealing in sequence to obtain a tin-brass alloy strip;

[0039] In the first stage rough rolling, the total reduction ratio of the first stage rough rolling is 69%, and the rolling temperature is room temperature. After the first stage rough rolling, the volume fraction of the Brass texture in the rolled and deformed tin brass alloy plate is 18%.

[0040] In the intermediate annealing step, the holding temperature of the intermediate annealing is 530° C. and the holding time is 2 hours. After the rolled and deformed tin-brass alloy plate undergoes the intermediate annealing step, the volume fraction of the Brass texture is 18%.

[0041] In the second stage finishing rolling step: the total reduction ratio of the second stage finishing rolling is 83%, and the rolling temperature is room temperature.

[0042] In the final annealing step: the holding temperature of the final annealing is 450°C and the holding time is 3 hours;

[0043] After the final annealing step, a tin-brass alloy strip is obtained;

[0044] The average volume fractions of the various texture components in the tin brass alloy strip prepared according to the preparation method of Example 1 are as follows:

[0045] Cube texture 11vol%, Copper texture 14vol%, Brass texture 13vol%, Goss texture 13vol%, S texture 26vol%.

[0046] Example 2:

[0047] Example 2 provides a method for preparing a tin-brass alloy strip, comprising the following steps:

[0048] The hot-rolled tin-brass alloy sheet is subjected to milling, first-stage rough rolling, intermediate annealing, second-stage finish rolling, and final annealing in sequence to obtain a tin-brass alloy strip;

[0049] In the first stage rough rolling, the total reduction ratio of the first stage rough rolling is 69%, and the rolling temperature is room temperature. After the first stage rough rolling, the volume fraction of the Brass texture in the rolled and deformed tin brass alloy plate is 18%.

[0050] In the intermediate annealing step, the holding temperature of the intermediate annealing is 530° C. and the holding time is 2 hours. After the rolled and deformed tin-brass alloy plate undergoes the intermediate annealing step, the volume fraction of the Brass texture is 18%.

[0051] In the second stage finishing rolling process, the total reduction ratio of the second stage finishing rolling is 83%, and the rolling temperature is 250°C to 300°C.

[0052] In the final annealing step: the holding temperature of the final annealing is 450°C and the holding time is 3 hours;

[0053] After the final annealing step, a tin-brass alloy strip is obtained;

[0054] The average volume fractions of the various texture components in the tin brass alloy strip prepared according to the preparation method of Example 2 are as follows:

[0055] Cube texture 14vol%, Copper texture 20vol%, Brass texture 7vol%, Goss texture 18vol%, S texture 21vol%.

[0056] Example 3:

[0057] Example 3 provides a method for preparing a tin-brass alloy strip, comprising the following steps:

[0058] The hot-rolled tin-brass alloy sheet is subjected to milling, first-stage rough rolling, intermediate annealing, second-stage finish rolling, and final annealing in sequence to obtain a tin-brass alloy strip;

[0059] In the first stage rough rolling, the total reduction ratio of the first stage rough rolling is 80%, and the rolling temperature is room temperature. After the first stage rough rolling, the volume fraction of the Brass texture in the rolled and deformed tin brass alloy plate is 26%.

[0060] In the intermediate annealing step, the holding temperature of the intermediate annealing is 530° C. and the holding time is 2 hours. After the rolled and deformed tin-brass alloy plate undergoes the intermediate annealing step, the volume fraction of the Brass texture is 12%.

[0061] In the second stage finishing rolling step: the total reduction ratio of the second stage finishing rolling is 75%, and the rolling temperature is room temperature.

[0062] In the final annealing step: the holding temperature of the final annealing is 450°C and the holding time is 3 hours;

[0063] After the final annealing step, a tin-brass alloy strip is obtained;

[0064] The average volume fractions of the various texture components in the tin brass alloy strip prepared according to the preparation method of Example 3 are as follows:

[0065] Cube texture 8vol%, Copper texture 13vol%, Brass texture 18vol%, Goss texture 11vol%, S texture 29vol%.

[0066] Comparative Example 1

[0067] Comparative Example 1 provides a method for preparing a tin-brass alloy strip, comprising the following steps:

[0068] The hot-rolled tin-brass alloy sheet is subjected to milling, first-stage rough rolling, intermediate annealing, second-stage finish rolling, and final annealing in sequence to obtain a tin-brass alloy strip;

[0069] In the first stage rough rolling, the total reduction ratio of the first stage rough rolling is 87.5%, and the rolling temperature is room temperature. After the first stage rough rolling, the volume fraction of the Brass texture in the rolled and deformed tin brass alloy plate is 33%.

[0070] In the intermediate annealing step, the holding temperature of the intermediate annealing is 530° C. and the holding time is 2 hours. After the rolled and deformed tin-brass alloy sheet undergoes the intermediate annealing step, the volume fraction of the Brass texture is 6%.

[0071] In the second stage finishing rolling step: the total reduction ratio of the second stage finishing rolling is 57.5%, and the rolling temperature is room temperature.

[0072] In the final annealing step: the holding temperature of the final annealing is 450°C and the holding time is 3 hours;

[0073] After the final annealing step, the tin brass alloy strip is obtained.

[0074] The average volume fractions of the various texture components in the tin brass alloy strip obtained according to the preparation method of Comparative Example 1 are as follows:

[0075] Cube texture 3vol%, Copper texture 12vol%, Brass texture 23vol%, Goss texture 5vol%, S texture 38vol%.

[0076] The tin-brass alloy plate in Examples 1, 2, 3 and Comparative Example 1 is a HSn90-1 tin-brass alloy plate.

[0077] The preparation methods of the tin-brass alloy strips in Examples 1, 2, and 3 and the effects that can be achieved by the tin-brass alloy strips can be seen from the following description:

[0078] (1) By Figure 1 It can be seen that as the first-stage rough rolling reduction rate increases, the grains of the tin-brass alloy strip are significantly elongated along the rolling direction, a distinct fibrous structure appears, the grain boundary density increases, and the grain size decreases with increasing cold rolling reduction rate. The grain morphology gradually evolves from elongated deformed grains to a broken subgrain structure. The grain orientation also changes from a predominantly {001} orientation to {101} and {111} orientations.

[0079] Figure 1Middle: (a), (b), (c) are schematic diagrams of EBSD counter-electrode of tin-brass alloy strip at the first stage rough rolling reduction ratios of 69%, 80%, and 87.5%, respectively;

[0080] (2) By Figure 2 It can be seen that with the increase of the first stage rough rolling reduction rate, the content of deformation textures such as Brass and S in the tin-brass alloy strip increases significantly. The average volume fraction of each texture component in the microstructure of the tin-brass alloy strip at different reduction rates is as follows:

[0081] Cold rolling reduction rate 69%: Cube texture 2.5vol%, Copper texture 2vol%, Brass texture 18vol%, Goss texture 1.5vol%, S texture 22vol%;

[0082] Cold rolling reduction rate 80%: Cube texture 0.5vol%, Copper texture 12vol%, Brass texture 26vol%, Goss texture 4vol%, S texture 22vol%;

[0083] Cold rolling reduction rate 87.5%: Cube texture 1.5vol%, Copper texture 10vol%, Brass texture 33vol%, Goss texture 2vol%, S texture 26vol%.

[0084] in, Figure 2 (a) shows the distribution of texture components of the tin brass alloy strip at a first-stage rough rolling reduction of 69%; (b) shows the distribution of texture components of the tin brass alloy strip at a first-stage rough rolling reduction of 80%; (c) shows the distribution of texture components of the tin brass alloy strip at a first-stage rough rolling reduction of 87.5%; (d) shows the average volume fraction of each texture component.

[0085] (3) By Figure 3 It can be seen that after intermediate annealing, the microstructure of the tin-brass alloy strips with different rough rolling reduction ratios undergoes complete recrystallization, the grains are transformed from elongated and broken into equiaxed grains, and the randomness of the grain orientation is enhanced;

[0086] Figure 3 (a) represents the EBSD inverse pole figure of the tin brass alloy strip (intermediate annealing state) at a first-stage rough rolling reduction of 69%; (b) represents the EBSD inverse pole figure of the tin brass alloy strip (intermediate annealing state) at a first-stage rough rolling reduction of 80%; (c) represents the EBSD inverse pole figure of the tin brass alloy strip (intermediate annealing state) at a first-stage rough rolling reduction of 87.5%;

[0087] (4) By Figure 4It can be seen that after intermediate annealing, more Goss texture appears in the microstructure of the tin-brass alloy strip with a lower rough rolling reduction rate. The average volume fraction of each texture component in the microstructure of the tin-brass alloy strip at different rough rolling reduction rates is as follows:

[0088] Cold rolling reduction rate 69%: Cube texture 3vol%, Copper texture 8vol%, Brass texture 8vol%, Goss texture 18vol%, S texture 16vol%;

[0089] Cold rolling reduction rate 80%: Cube texture 4vol%, Copper texture 11vol%, Brass texture 8vol%, Goss texture 12vol%, S texture 15vol%;

[0090] Cold rolling reduction rate 87.5%: Cube texture 6vol%, Copper texture 11vol%, Brass texture 9vol%, Goss texture 6vol%, S texture 21vol%.

[0091] Figure 4 Among them, (a) represents the distribution of texture components of the tin brass alloy strip (intermediate annealing state) at a first-stage rough rolling reduction rate of 69%; (b) represents the distribution of texture components of the tin brass alloy strip (intermediate annealing state) at a first-stage rough rolling reduction rate of 80%; (c) represents the distribution of texture components of the tin brass alloy strip (intermediate annealing state) at a first-stage rough rolling reduction rate of 87.5%; (d) is the average volume fraction of each texture component;

[0092] (5) By Figure 5 、 Figure 6 It can be seen that after the second stage of finishing rolling and final annealing, the grain size of the tin-brass alloy strip further refines. With increasing cold rolling reduction, the grain size decreases. Warm-rolled strips with the same cold rolling reduction have larger grain sizes. The strips with finishing reductions of 57.5%, 75%, and 83% correspond to grain sizes of 5.9μm, 4.6μm, and 2.8μm, respectively. The strip with an 83% finishing reduction combined with warm rolling has a grain size of 4.9μm.

[0093] Figure 5 Among them, (a) represents the EBSD inverse pole figure of the tin brass alloy strip (final annealed state) at a second-stage finishing rolling reduction of 83%; (b) represents the EBSD inverse pole figure of the tin brass alloy strip (final annealed state) at a second-stage finishing rolling reduction of 83% and warm rolling; (c) represents the EBSD inverse pole figure of the tin brass alloy strip (final annealed state) at a second-stage finishing rolling reduction of 75%; (d) represents the EBSD inverse pole figure of the tin brass alloy strip (final annealed state) at a second-stage finishing rolling reduction of 57.5%;

[0094] Figure 6 Among them, (a) represents the grain size distribution frequency histogram of the tin brass alloy strip (final annealed state) at a second-stage finishing rolling reduction of 83%; (b) represents the grain size distribution frequency histogram of the tin brass alloy strip (final annealed state) at a second-stage finishing rolling reduction of 83% and warm rolling; (c) represents the grain size distribution frequency histogram of the tin brass alloy strip (final annealed state) at a second-stage finishing rolling reduction of 75%; (d) represents the grain size distribution frequency histogram of the tin brass alloy strip (final annealed state) at a second-stage finishing rolling reduction of 57.5%;

[0095] (6) By Figure 7 It can be seen that with increasing finishing reduction, the volume fraction of recrystallized textures such as Cube and Goss increases in the microstructure of the tin-brass alloy strip in the final annealed state, while the volume fraction of deformation textures such as Brass and S decreases. In the strip subjected to 83% finishing reduction plus warm rolling, the volume fractions of Cube and Goss further increase, while the volume fractions of Brass and S decrease. After final annealing, the average volume fractions of each texture component in the microstructure of the tin-brass alloy strips with different finishing reductions are as follows:

[0096] Cold rolling reduction ratio 57.5%: Cube texture 3vol%, Copper texture 12vol%, Brass texture 23vol%, Goss texture 5vol%, S texture 38vol%;

[0097] Cold rolling reduction rate 75%: Cube texture 8vol%, Copper texture 13vol%, Brass texture 18vol%, Goss texture 11vol%, S texture 29vol%;

[0098] Cold rolling reduction ratio 83%: Cube texture 11vol%, Copper texture 14vol%, Brass texture 13vol%, Goss texture 13vol%, S texture 26vol%;

[0099] Cold rolling reduction rate 83% + warm rolling: Cube texture 14vol%, Copper texture 20vol%, Brass texture 7vol%, Goss texture 18vol%, S texture 21vol%.

[0100] Figure 7Among them, (a) is the distribution of texture components of the tin brass alloy strip (final annealed state) at a second-stage finishing rolling reduction of 83%; (b) is the distribution of texture components of the tin brass alloy strip (final annealed state) at a second-stage finishing rolling reduction of 83% + warm rolling; (c) is the distribution of texture components of the tin brass alloy strip (final annealed state) at a second-stage finishing rolling reduction of 75%; (d) is the distribution of texture components of the tin brass alloy strip (final annealed state) at a second-stage finishing rolling reduction of 57.5%; (e) is the average volume fraction of each texture component;

[0101] Table 1: Macroscopic morphology of the outer surface of the strips in the embodiment and comparative example at different bending radii

[0102]

[0103] (7) By Figure 8 、 Figure 9 As shown in Table 1, when the total reduction rate of the first stage rough rolling is 69%, the reduction rate of the second stage finishing rolling is 83%, and the rolling temperature is room temperature, the average grain size of the tin-brass alloy strip is the smallest, which is only 2.8μm. At the same time, due to the high volume fraction of Cube texture and Goss texture in the microstructure that are beneficial to the bending performance, and the low volume fraction of Brass texture and S texture that are not conducive to the bending performance, the highest tensile strength is obtained. The tensile strength of the strip can reach 409MPa, and the elongation also reaches 42.8%. There is no obvious wrinkling on the bending surface of the strip at a bending radius of 0.4mm, and only slight wrinkles are produced at a bending radius of 0.16mm. When the second stage finishing rolling temperature is increased to 250℃~300℃, and other process conditions remain unchanged, the volume fraction of Cube texture and Goss texture in the microstructure of the tin-brass alloy strip is further improved, and Brass texture and S texture are more uniform. The volume fraction of s texture and S texture further decreased, so that the strip obtained the best bending performance. No obvious wrinkling occurred on the bending surface at bending radii of 0.4 mm and 0.16 mm. However, due to the increase in the average grain size of the strip to 4.9 μm, its tensile strength and elongation decreased slightly, to 382 MPa and 39.4%, respectively. When the second-stage finishing rolling reduction was 75%, the tensile strength and elongation of the strip were 364 MPa and 41.3%, respectively. Slight wrinkling occurred on the bending surface at a bending radius of 0.4 mm, and slight cracking occurred on the bending surface at a bending radius of 0.16 mm. When the second-stage finishing rolling reduction was 57.5%, the tensile strength and elongation of the strip were 335 MPa and 44%, respectively. Obvious wrinkling occurred on the bending surface at a bending radius of 0.4 mm, and obvious cracking occurred on the bending surface at a bending radius of 0.16 mm.

[0104] Figure 8 In the figure, (a) is the tensile curve and (b) is the tensile property;

[0105] Figure 9 Among them, (a) is the bending surface morphology of the tin brass alloy strip (final annealed state) at a second-stage finishing rolling reduction of 83%; (b) is the bending surface morphology of the tin brass alloy strip (final annealed state) at a second-stage finishing rolling reduction of 83% and warm rolling; (c) is the bending surface morphology of the tin brass alloy strip (final annealed state) at a second-stage finishing rolling reduction of 75%; (d) is the bending surface morphology of the tin brass alloy strip (final annealed state) at a second-stage finishing rolling reduction of 57.5%;

[0106] The data of the above embodiments and comparative examples can be seen in the following table:

[0107] Table 2: Data table of examples and comparative examples

[0108]

[0109] The data in Table 2 above demonstrates that the present invention aims to improve the strength and bendability of HSn90-1 tin-brass alloy strip. By precisely controlling the two-stage rolling process during cold rolling, combined with warm rolling, the present invention achieves precise control of microstructural characteristics such as texture composition and grain size, thereby improving the strip's tensile strength and bendability. Compared to compositional modification methods such as microalloying, the present invention significantly improves the tensile strength and bendability of tin-brass alloy strip without adding precious alloying elements, thereby reducing production costs and producing a low-cost tin-brass alloy strip with excellent formability and serviceability.

[0110] Specifically, the present invention reduces the first-stage rough rolling reduction rate to obtain a lower Brass texture in the deformed microstructure, making the annealing process more conducive to the nucleation of Goss texture, thereby obtaining more Goss texture; at the same time, since the thickness of the hot-rolled plate and the thickness of the final finished product are basically fixed values, for example, the hot-rolled plate thickness is 16 mm, and the corresponding finished strip thickness is 0.85 mm, so the smaller the first-stage rough rolling reduction rate, the higher the second-stage finishing reduction rate, and the formation of Cube texture depends on the recrystallization process after high deformation, so a higher second-stage finishing reduction rate is more conducive to ensuring that more Cube texture is obtained after low-temperature annealing; when the second-stage finishing rolling adopts an appropriate warm rolling temperature (250°C to 300°C), the accumulated deformation energy storage during the rolling process can be appropriately reduced, which is conducive to reducing the formation of deformation textures such as Brass and S and promoting the formation of recrystallization textures such as Cube and Goss; in addition, with the increase of the second-stage finishing reduction rate, the grain size of the tin-brass alloy strip after final annealing is significantly reduced, and the tensile strength of the strip is significantly improved.

[0111] Comparison of the performance of the tin-brass alloy strips in Example 1, Example 2, and Comparative Example 1 shows that when the total reduction ratio of the first stage rough rolling is 69%, the second stage finishing rolling reduction ratio is 83%, and the rolling temperature is room temperature (preparation method in Example 1), the average volume fraction of each texture component of the tin-brass alloy strip is as follows: Cube texture 11 vol%, Copper texture 14 vol%, Brass texture 13 vol%, Goss texture 13 vol%, S texture 26 vol%, and the tensile strength of the strip is 409 M Pa, the elongation is 42.8%, no obvious wrinkles occur on the bending surface of the strip at a bending radius of 0.4 mm, and slight wrinkles occur at a bending radius of 0.16 mm; when the second stage finishing rolling temperature in the embodiment is increased to 250-300°C and the other step conditions remain unchanged (the preparation method of Example 2), the average volume fraction of each texture component of the tin-brass alloy strip is as follows: Cube texture 14 vol%, Copper texture 20 vol%, Brass texture 7 vol%, Goss texture 18 vol %, S texture 21 vol%, the strip tensile strength was 382 MPa, the elongation was 39.4%, and no obvious wrinkling occurred on the strip surface at bending radii of 0.4 mm and 0.16 mm, indicating that the bending performance was further improved at the expense of a small amount of strength and plasticity. When the total reduction ratio of the first stage rough rolling was 87.5%, the reduction ratio of the second stage finish rolling was 57.5%, and the rolling temperature was room temperature (preparation method in Comparative Example 1), the texture components of the tin brass alloy strip were as follows: Cube texture 3. 1vol%, Copper texture 11.8vol%, Brass texture 22.8vol%, Goss texture 4.5vol%, S texture 38.2vol%, the strip tensile strength is 335MPa, the elongation is 44%, the strip has obvious wrinkles on the bending surface at a bending radius of 0.4mm, and obvious cracking occurs at a bending radius of 0.16mm, that is, except for a slight improvement in plasticity, the tensile strength and bending performance of the tin-brass alloy strip are significantly lower than those of the tin-brass alloy strip obtained in the embodiment of the present invention.

[0112] The comparative results show that the present invention can achieve precise regulation of the microstructural characteristics of HSn90-1 tin brass alloy strip, such as texture composition and grain size, through precise control of the rolling schedule combined with the warm rolling process, thereby significantly improving the tensile strength and bending performance of the tin brass alloy strip without adding precious alloying elements, which is beneficial to reducing production costs and providing a guarantee for the service performance of tin brass materials used in key electrical contact devices.

[0113] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0114] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A tin-brass alloy strip, characterized in that: The volume fraction of each texture component in the tin-brass alloy strip is: Cube texture 8vol%~14vol%, Copper texture 13vol%~20vol%, Brass texture 7vol%~18vol%, Goss texture 11vol%~18vol%, S texture 21vol%~29vol%.

2. A method for preparing a tin-brass alloy strip, wherein the method is used to prepare the tin-brass alloy strip according to claim 1, characterized in that: The steps include: The hot-rolled tin-brass alloy sheet is subjected to milling, first-stage rough rolling, intermediate annealing, second-stage finish rolling, and final annealing in sequence to obtain the tin-brass alloy strip; The total reduction ratio of the first stage rough rolling is 69% to 80%, and the rolling temperature is room temperature.

3. The preparation method according to claim 2, characterized in that After the tin-brass alloy plate undergoes the first stage rough rolling step, the volume fraction of the Brass texture in the tin-brass alloy plate is 18% to 26%.

4. The preparation method according to claim 2, characterized in that In the intermediate annealing step, the intermediate annealing temperature is 530° C. and the holding time is 2 hours.

5. The preparation method according to claim 2, characterized in that After the tin-brass alloy plate undergoes the intermediate annealing step, the volume fraction of the Brass texture in the tin-brass alloy plate is 12% to 18%.

6. The preparation method according to claim 2, characterized in that In the second stage finishing rolling step: The total reduction ratio of the second stage finishing rolling is 75% to 83%, and the rolling temperature is room temperature.

7. The preparation method according to claim 2, characterized in that In the second stage finishing rolling step: The total reduction ratio of the second stage finishing rolling is 75% to 83%, and the rolling temperature is 250° C. to 300° C.

8. The preparation method according to claim 2, characterized in that In the step of the final annealing treatment: the holding temperature of the final annealing is 450° C. and the holding time is 3 hours.

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