A high-strength / strong cube-textured metal strip and its preparation method

Abstract

The present invention discloses a high-strength / strong cube texture metal strip and a preparation method thereof. By designing the alloy composition, appropriate amounts of elements such as W, C, Cr, Mo, Cu, and V are added on the basis of the Ni alloy. On the premise of improving the ferromagnetic property, the rolling and heat treatment processes are regulated, and the heat treatment atmosphere is reasonably matched, and finally a strip with a strong cube texture and high strength can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of preparing metal substrates for second-generation high-temperature coated superconducting tapes, and particularly relates to a high-strength / strong cube texture metal strip and a preparation method thereof. Background Art

[0002] For second-generation high-temperature superconducting materials represented by YBaCuO, long wires / tape can be obtained only by preparing YBaCuO thin films deposited on a ductile metal substrate. The deposition of superconducting thin films and the application of superconducting tapes require that the metal substrate has high strength and strong cube texture. Ni-W alloy is a metal substrate material that has been studied more, but it is difficult to simultaneously obtain strong cube texture, non-ferromagnetism, and high strength. Generally, as the substrate strength increases, the content of recrystallized cube texture decreases significantly, and it is difficult to take into account cube texture, non-ferromagnetism, and strength at the same time. At present, strong cube texture, non-ferromagnetism, and mechanical properties can be simultaneously achieved in laminated composites, but it is difficult to prepare large-size and longer composite tapes. In single-layer metal strips, the methods for regulating cube texture and mechanical properties mainly focus on Ni-W alloys. The preparation of single-layer strips is easy to realize industrial production, but the strength and ferromagnetism still need to be further improved. Therefore, developing new alloy compositions and corresponding preparation technologies is the key to developing high-performance metal substrates for new superconducting tapes. Summary of the Invention

[0003] Aiming at the deficiencies of the above-mentioned existing technologies, the present invention provides a high-strength / strong cube texture metal strip and a preparation method thereof, which can make the metal strip form a strong cube texture at high temperature and obtain high strength at the same time.

[0004] The present invention provides a high-strength / strong cube texture metal strip, and the chemical composition of the metal strip is: 0.02-0.03% C, 6-7% W, 1.2-1.8% Cr, 1.5-2% Mo, 1.5-2% Cu, 2.5-3% V, and the balance is Ni, all in weight percentages.

[0005] The present invention also provides a preparation method for the above-mentioned high-strength / strong cube texture metal strip, including the following steps:

[0006] Step (1): Obtain an alloy with the above composition by melting and forge it into an ingot with a thickness of 50 mm - 60 mm, and control the final forging temperature above 1000 °C;

[0007] Step (2): Hot-roll the ingot obtained in step (1), wherein the hot-rolling heating temperature is 1100 °C, keep warm for 30 minutes - 40 minutes, the hot-rolled thickness is 10 mm - 12 mm, and control the final rolling temperature above 1000 °C;

[0008] Step (3): Grind the scale on the surface of the hot-rolled sheet obtained in step (2), and then cold-roll it to a thickness of 2 mm to 2.5 mm, followed by heat treatment. The specific process of the heat treatment is: heat up to 520 °C and hold for 2 hours;

[0009] Step (4): Cold-roll the heat-treated strip obtained in step (3) to 0.5 mm, and then conduct heat treatment. The specific process of the heat treatment is: heat up to 520 °C and hold for 2 hours;

[0010] Step (5): Cold-roll the strip obtained in step (4) to 0.08 mm to 0.09 mm, and then conduct heat treatment. The specific process of the heat treatment is to hold at 580 °C to 600 °C for 30 minutes, then heat up to 900 °C and hold for 30 minutes, and finally heat up to 1200 °C and hold for 2 hours.

[0011] Furthermore, the specific process of the heat treatment in step (3) and step (4) is: heat up to 520 °C and hold for 2 hours.

[0012] Furthermore, the atmosphere of the heat treatment in step (5) is: argon protection before heating up to 1100 °C, with a purity of 99.99 to 99.999%; after heating up to 1100 °C, the atmosphere is switched to a mixture of ammonia decomposition gas and pure nitrogen, where the volume fraction of nitrogen is 10% to 15%.

[0013] The beneficial technical effects of the present invention: By adding appropriate amounts of Cr, Mo, Cu, and V, the ferromagnetic property of the strip can be reduced. Additionally adding an appropriate amount of C can form carbides, refine the grain size after ingot casting and hot rolling, facilitate uniform deformation during subsequent cold rolling, and retain cubic-oriented grains. Through multiple intermediate heat treatments, full recovery of the cubic orientation can be further achieved, and then retained in the final cold-rolled strip as seeds for recrystallization nucleation. The purpose of the subsequent three-step high-temperature heat treatment is to allow the cubic-oriented seeds retained by cold rolling to preferentially undergo recovery, recrystallization nucleation, and growth at low temperatures first, and then utilize their size advantage to engulf non-cubic-oriented grains at high temperatures, thereby obtaining a strong cubic texture. Through heat treatment atmosphere control, nitride can be formed to pin grain growth, achieving fine grain strengthening and obtaining high strength. Description of the Drawings

[0014] Figure 1 The {111} pole figure after heat treatment when cold-rolled to 0.5 mm in Example 1;

[0015] Figure 2 The {100} pole figure after the final high-temperature heat treatment in Example 1;

[0016] Figure 3 The {100} pole figure after the final high-temperature heat treatment in Example 2;

[0017] Figure 4 The {100} pole figure after the final high-temperature heat treatment in Example 3. Detailed implementation manners

[0018] The present invention will be described in detail below in conjunction with Table 1 and the detailed implementation manners. Example 1

[0019] An alloy ingot was obtained by vacuum induction melting. The alloy composition was: 0.02% C, 6% W, 1.8% Cr, 2% Mo, 2% Cu, 3% V, and the balance was Ni, all in weight percentages. The melted alloy was forged into a billet with a thickness of 50 mm, and the final forging temperature was controlled at 1020 °C. Then hot rolling was carried out. The heating temperature was 1100 °C, and the holding time was 40 minutes. The hot-rolled thickness was 12 mm, and the final rolling temperature was controlled at 1030 °C. After the oxide scale on the surface of the hot-rolled plate was polished, it was cold-rolled to a thickness of 2.5 mm. Subsequently, heat treatment was carried out. The specific process was: heating to 520 °C and holding for 2 hours. The obtained heat-treated strip was cold-rolled to 0.5 mm, and then heat treatment was carried out. The specific process was: heating to 520 °C and holding for 2 hours. The {111} texture of the strip was as Figure 1 shown. It can be clearly seen that the strip retained part of the cube texture. Then the obtained strip was cold-rolled to 0.08 mm, and finally high-temperature heat treatment was carried out. The specific process was: holding at 600 °C for 30 minutes, then heating to 900 °C and holding for 30 minutes, and finally heating to 1200 °C and holding for 2 hours. Among them, the heat treatment atmosphere was: argon protection with a purity of 99.99% before heating to 1100 °C, and after heating to 1100 °C, the atmosphere was switched to a mixture of ammonia decomposition gas and pure nitrogen, in which the volume fraction of nitrogen was 15%. Finally, a strip with high strength / strong cube texture was obtained. The {100} pole figure of the final strip was as Figure 2 shown, and the surface was a sharp cube texture. The tensile strength and cube texture content are shown in Table 1. Example 2

[0020] An alloy ingot was obtained by vacuum induction melting. The alloy composition is: 0.03%C, 6%W, 1.2%Cr, 1.5%Mo, 1.5%Cu, 2.5%V, and the rest is Ni, all in weight percentages. The melted alloy was forged into a billet with a thickness of 60 mm, and the final forging temperature was controlled at 1010 °C. Then hot rolling was carried out, the heating temperature was 1100 °C, holding for 30 minutes, the hot rolling thickness was 10 mm, and the final rolling temperature was controlled at 1020 °C; after the oxide scale on the surface of the hot-rolled plate was polished, it was cold-rolled to a thickness of 2 mm, and then heat treatment was carried out. The specific process was: heating to 520 °C and holding for 2 hours. The heat-treated strip obtained above was cold-rolled to 0.5 mm, and then heat treatment was carried out. The specific process was: heating to 520 °C and holding for 2 hours; then the obtained strip was cold-rolled to 0.09 mm, and finally high-temperature heat treatment was carried out. The specific process was 580 °C for 30 minutes, then heating to 900 °C and holding for 30 minutes, and finally heating to 1200 °C and holding for 2 hours. Among them, the heat treatment atmosphere was: argon protection before heating to 1100 °C, with a purity of 99.999%. After heating to 1100 °C, the atmosphere was switched to a mixture of ammonia decomposition gas and pure nitrogen, in which the volume fraction of nitrogen was 10%. Finally, a strip with high strength / strong cube texture was obtained. The {100} pole figure of the final strip is as Figure 3 shown, the surface is a sharp cube texture, and the tensile strength and cube texture content are shown in Table 1. Example 3

[0021] An alloy ingot was obtained by vacuum induction melting. The alloy composition is: 0.02%C, 7%W, 1.8%Cr, 2%Mo, 2%Cu, 3%V, and the rest is Ni, all in weight percentages. The melted alloy was forged into a billet with a thickness of 60 mm, and the final forging temperature was controlled at 1030 °C. Then hot rolling was carried out, the heating temperature was 1100 °C, holding for 40 minutes, the hot rolling thickness was 12 mm, and the final rolling temperature was controlled at 1010 °C; after the oxide scale on the surface of the hot-rolled plate was polished, it was cold-rolled to a thickness of 2.5 mm, and then heat treatment was carried out. The specific process was: heating to 520 °C and holding for 2 hours. The heat-treated strip obtained above was cold-rolled to 0.5 mm, and then heat treatment was carried out. The specific process was: heating to 520 °C and holding for 2 hours; then the obtained strip was cold-rolled to 0.08 mm, and finally high-temperature heat treatment was carried out. The specific process was 580 °C for 30 minutes, then heating to 900 °C and holding for 30 minutes, and finally heating to 1200 °C and holding for 2 hours. Among them, the heat treatment atmosphere was: argon protection before heating to 1100 °C, with a purity of 99.99%. After heating to 1100 °C, the atmosphere was switched to a mixture of ammonia decomposition gas and pure nitrogen, in which the volume fraction of nitrogen was 10%. Finally, a strip with high strength / strong cube texture was obtained. The {100} pole figure of the final strip is as Figure 4 shown, the surface is a sharp cube texture, and the tensile strength and cube texture content are shown in Table 1.

[0022] Table 1 Tensile strength and cube texture content of the strip in Examples 1 to 3

[0023]

Claims

1. A method for preparing a high-strength / strong cubic texture metal strip, characterized in that: The chemical composition of the metal strip is: 0.02-0.03% C, 6-7% W, 1.2-1.8% Cr, 1.5-2% Mo, 1.5-2% Cu, 2.5-3% V, and the rest is Ni, all in weight percentage, and includes the following steps: Step (1): obtaining an alloy of the aforementioned composition by smelting, and forging it into an ingot with a thickness of 50 mm to 60 mm, with the final forging temperature being controlled at above 1000°C; Step (2): hot rolling the billet obtained in step (1), wherein the hot rolling heating temperature is 1100° C., the heat preservation time is 30 minutes to 40 minutes, the hot rolling thickness is 10 mm to 12 mm, and the final rolling temperature is controlled at above 1000° C.; Step (3): grinding the oxide scale on the surface of the hot-rolled plate obtained in step (2), cold-rolling the plate to a thickness of 2 mm to 2.5 mm, and then heat treating the plate; Step (4): cold rolling the heat-treated strip obtained in step (3) to 0.5 mm, and then heat treating; Step (5): cold rolling the strip obtained in step (4) to 0.08 mm to 0.09 mm, and then performing heat treatment; The specific process of heat treatment in step (3) and step (4) is as follows: heating to 520°C and keeping the temperature for 2 hours; The specific process of the heat treatment in step (5) is to keep the temperature at 580°C-600°C for 30 minutes, then raise the temperature to 900°C for 30 minutes, and finally raise the temperature to 1200°C for 2 hours; The atmosphere for the heat treatment in step (5) is: before the temperature is raised to 1100° C., the atmosphere is protected by argon gas with a purity of 99.99-99.999%; after the temperature is raised to 1100° C., the atmosphere is switched to a mixture of ammonia decomposition gas and pure nitrogen, wherein the volume fraction of nitrogen is 10-15%.

2. A high strength / strong cubic texture metal strip, characterized in that: The method according to claim 1 is used for preparation.

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