Method for preparing ultra-fine crystal grain high-strength high-toughness copper alloy strip

Abstract

The invention discloses a method for preparing an ultra-fine crystal grain high-strength high-toughness copper alloy strip. The method comprises the following steps of: performing hot-rolling with the distortion of 40 to 70 percent after performing high-temperature annealing on a copper alloy cast ingot to obtain a plate blank; performing cold-rolling with the distortion of 30 to 60 percent; performing intermediate annealing after the cold-rolling; after soaking the plate blank in liquid nitrogen for 5 to 30 minutes, taking the plate blank out and performing the cold rolling immediately; performing cryogenic treatment and the cold-rolling repeatedly after performing the cold-rolling; after accumulated strain capacity reaches 40 to 90 percent, performing low-temperature annealing to obtain the ultra-fine crystal grain high-strength high-toughness copper alloy strip with the average size of about 0.8 mu m, wherein the tensile strength of the copper alloy strip is 650 to 880 MPa and the elongation rate is 10 to 30 percent. The method has a simple production process and low processing cost, and can implement cold-deformation and annealing after the cryogenic treatment on a copper alloy on conventional production equipment; crystal grains are thinned by generated deformation twin and annealing twin, simultaneously both the strength and the tensility of the copper alloy are improved; therefore, the method has a very good industrial application prospect.

Description

technical field

[0001] The invention relates to a preparation method of a brass strip, in particular to a copper strip with ultra-fine crystal grains, high strength and high toughness and a preparation method thereof. It belongs to the technical field of thermal processing of nonferrous metals. Background technique

[0002] In recent years, with the rapid development of communication, electronics, electric power industry and other fields, the application range of copper and its alloy strip products has been expanding, and higher requirements have been put forward for its performance. Copper alloy strips are of great significance.

[0003] Grain refinement is one of the most effective ways to increase the strength of materials. At present, ultra-fine-grained materials are mainly prepared through severe plastic deformation such as high-pressure torsion and equal-channel angular extrusion. The above methods require special molds, and the preparation process is cumbersome, cos...

Examples

Embodiment 1

[0037] The brass alloy ingot containing 70% copper is annealed at 800°C for 1 hour and then hot rolled, the deformation is controlled to 60%, and the hot rolling temperature is 780°C to obtain a slab; the slab is subjected to 600°C for 1 hour After the intermediate annealing, cold rolling is carried out, and the deformation is controlled to 50%; after the cold rolling, an intermediate annealing is carried out for 1 hour, and the annealing temperature is 350 ° C; Soak the test piece in liquid nitrogen for 10 minutes. After the single-pass cold rolling, quickly soak the test piece in liquid nitrogen, repeat cryogenic treatment and low-temperature cold rolling, and carry out low-temperature treatment at 300°C for 0.2 hours after the deformation reaches 50%. annealing. That is, the ultra-fine-grained high-strength and high-toughness copper alloy strip of the present invention is obtained. See attached figure 1 It can be seen that after low-temperature annealing, the entire struc...

Embodiment 2

[0039] The brass alloy ingot containing 68% copper is annealed at 700°C for 2 hours and then hot rolled, the deformation is controlled to 40%, and the hot rolling temperature is 700°C to obtain a slab; the slab is subjected to 680°C for 2 hours After the intermediate annealing, cold rolling is carried out, and the deformation is controlled to 60%; after the cold rolling, the intermediate annealing is carried out for 2 hours, and the annealing temperature is 450 ° C; Soak the test piece in liquid nitrogen for 5 minutes. After the single-pass cold rolling, quickly soak the test piece in liquid nitrogen, repeat cryogenic treatment and low-temperature cold rolling, and carry out low-temperature treatment at 250°C for 0.5 hours after the deformation reaches 60%. annealing. Promptly get the copper alloy strip with ultra-fine grain, high strength and high toughness of the present invention. image 3 It can be seen that after low-temperature annealing, the microstructure has been uni...

Embodiment 3

[0041] The brass alloy ingot containing 70% copper was annealed at 850°C for 0.5 hours, then water-cooled for hot rolling, the deformation was controlled to 70%, and the hot rolling temperature was 780°C to obtain a slab; the slab was subjected to 750°C for 0.5 hours After the intermediate annealing, cold rolling is carried out, and the deformation is controlled at 30%; after the cold rolling, intermediate annealing is carried out for 0.5 hours, and the annealing temperature is 300°C; the slab at this time is cut into two parts, which are respectively numbered as the first group and the second group. two groups. Then the first group of test pieces were subjected to multi-pass cold rolling. During cold rolling, the test pieces were soaked in liquid nitrogen for 30 minutes before deformation in each pass, and repeated cryogenic treatment and low-temperature cold rolling. After the deformation reached 40%, every Cut a part of the test piece at a time for strength test until the d...

technical field

[0001] The invention relates to a preparation method of a brass strip, in particular to a copper strip with ultra-fine crystal grains, high strength and high toughness and a preparation method thereof. It belongs to the technical field of thermal processing of nonferrous metals. Background technique

[0002] In recent years, with the rapid development of communication, electronics, electric power industry and other fields, the application range of copper and its alloy strip products has been expanding, and higher requirements have been put forward for its performance. Copper alloy strips are of great significance.

[0003] Grain refinement is one of the most effective ways to increase the strength of materials. At present, ultra-fine-grained materials are mainly prepared through severe plastic deformation such as high-pressure torsion and equal-channel angular extrusion. The above methods require special molds, and the preparation process is cumbersome, cos...

Examples

Embodiment 1

[0037] The brass alloy ingot containing 70% copper is annealed at 800°C for 1 hour and then hot rolled, the deformation is controlled to 60%, and the hot rolling temperature is 780°C to obtain a slab; the slab is subjected to 600°C for 1 hour After the intermediate annealing, cold rolling is carried out, and the deformation is controlled to 50%; after the cold rolling, an intermediate annealing is carried out for 1 hour, and the annealing temperature is 350 ° C; Soak the test piece in liquid nitrogen for 10 minutes. After the single-pass cold rolling, quickly soak the test piece in liquid nitrogen, repeat cryogenic treatment and low-temperature cold rolling, and carry out low-temperature treatment at 300°C for 0.2 hours after the deformation reaches 50%. annealing. That is, the ultra-fine-grained high-strength and high-toughness copper alloy strip of the present invention is obtained. See attached figure 1 It can be seen that after low-temperature annealing, the entire struc...

Embodiment 2

[0039] The brass alloy ingot containing 68% copper is annealed at 700°C for 2 hours and then hot rolled, the deformation is controlled to 40%, and the hot rolling temperature is 700°C to obtain a slab; the slab is subjected to 680°C for 2 hours After the intermediate annealing, cold rolling is carried out, and the deformation is controlled to 60%; after the cold rolling, the intermediate annealing is carried out for 2 hours, and the annealing temperature is 450 ° C; Soak the test piece in liquid nitrogen for 5 minutes. After the single-pass cold rolling, quickly soak the test piece in liquid nitrogen, repeat cryogenic treatment and low-temperature cold rolling, and carry out low-temperature treatment at 250°C for 0.5 hours after the deformation reaches 60%. annealing. Promptly get the copper alloy strip with ultra-fine grain, high strength and high toughness of the present invention. image 3 It can be seen that after low-temperature annealing, the microstructure has been uni...

Embodiment 3

[0041] The brass alloy ingot containing 70% copper was annealed at 850°C for 0.5 hours, then water-cooled for hot rolling, the deformation was controlled to 70%, and the hot rolling temperature was 780°C to obtain a slab; the slab was subjected to 750°C for 0.5 hours After the intermediate annealing, cold rolling is carried out, and the deformation is controlled at 30%; after the cold rolling, intermediate annealing is carried out for 0.5 hours, and the annealing temperature is 300°C; the slab at this time is cut into two parts, which are respectively numbered as the first group and the second group. two groups. Then the first group of test pieces were subjected to multi-pass cold rolling. During cold rolling, the test pieces were soaked in liquid nitrogen for 30 minutes before deformation in each pass, and repeated cryogenic treatment and low-temperature cold rolling. After the deformation reached 40%, every Cut a part of the test piece at a time for strength test until the d...

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