Preparation method of high-strength Zn-Cu-Ti alloy plate

Abstract

The invention discloses a method for preparing a high-strength Zn-Cu-Ti alloy plate through liquid extrusion and composite straightening rolling technologies, and belongs to the technical field of metal material machining. Aiming at the problems that a traditional Zn-Cu-Ti alloy plate is complex in preparation process, high in cost, and insufficient in component segregation and mechanical property, alloy components are optimized, segregation and pore defects are reduced in combination with vacuum argon protection liquid extrusion, hot rolling, warm rolling and multi-pass cold rolling are synchronously completed by adopting a composite straightening rolling technology, and annealing treatment is assisted, so that the Zn-Cu-Ti alloy plate is obtained. And meanwhile, the technological process is simplified, the production cost is reduced, and the composite board is suitable for the fields of building light structures, industrial corrosion resistance and decorative materials and has the characteristics of high strength, light weight and environmental protection.

Description

Technical Field

[0001] This invention discloses a method for preparing high-strength Zn-Cu-Ti alloy plates using liquid extrusion and composite straightening rolling technology, belonging to the field of metal material processing technology. Background Technology

[0002] In the current context of the rapid development of the construction industry, the scale of large stadiums and industrial plants is constantly expanding. Currently, these buildings mostly use color-coated rolled steel sheets as roofing materials. However, with the increasing diversification of building demands, the drawbacks of this traditional material are becoming increasingly apparent. Its appearance lacks diversity, making it difficult to meet the unique aesthetic requirements of modern architecture. In terms of cost, color-coated rolled steel sheets are relatively expensive, putting significant pressure on construction project budgets. Furthermore, this material has obvious shortcomings in corrosion resistance and service life; frequent maintenance and replacement not only consume a large amount of manpower and resources but also affect the normal use of the building.

[0003] In this context, Zn-Cu-Ti alloy sheets have become a focus of attention in the building materials field due to their unique advantages. As a roofing structural material, Zn-Cu-Ti alloy sheets offer significant advantages. Their low density effectively reduces roof weight, lowering the overall building load and reducing the load-bearing requirements of the foundation, thus reducing construction costs. The alloy sheets offer a variety of design options to meet the needs of different architectural styles, adding unique charm to building appearances. In terms of performance, the corrosion resistance and service life of Zn-Cu-Ti alloy sheets far exceed those of color-coated rolled steel sheets. This is mainly due to the alloy's ability to form a dense protective film in the air, providing natural self-protection and enabling decades of maintenance-free roofing, significantly reducing later maintenance costs. Furthermore, Zn-Cu-Ti alloy sheets are fully recyclable, aligning with the concept of green building development and earning the reputation of "green building materials." Simultaneously, these alloy sheets also possess excellent heat resistance, cold resistance, fire resistance, and corrosion resistance, making them particularly suitable for lightweight building structures and architectural decoration, demonstrating enormous application potential in the construction field.

[0004] Despite the significant advantages of Zn-Cu-Ti alloy sheets, there is still room for improvement in their preparation technology. Traditional preparation methods have limitations in improving product strength, optimizing internal microstructure, and increasing production efficiency. For example, traditional processes struggle to precisely control the distribution and microstructure of elements within the alloy, resulting in product strength that cannot meet the demands of high-end construction. During the forming process, ingots are prone to defects such as porosity, voids, and microcracks, severely impacting product quality and performance. In the rolling stage, insufficient shape control leads to frequent edge waviness and center warping, reducing product shape accuracy and hindering rolling efficiency improvements. Therefore, developing more advanced and efficient Zn-Cu-Ti alloy sheet preparation technologies is crucial for fully leveraging their performance advantages and driving the development of the building materials industry. Summary of the Invention

[0005] To address the issues of complex manufacturing processes, high costs, component segregation, and insufficient mechanical properties in traditional Zn-Cu-Ti alloy sheet production, this paper proposes a method that optimizes the alloy composition, combines vacuum argon-protected liquid extrusion to reduce segregation and porosity defects, and employs a composite straightening rolling technology to simultaneously complete hot rolling, warm rolling, and multi-pass cold rolling, supplemented by annealing. This significantly improves the density and mechanical properties of the sheet, while simplifying the process and reducing production costs. It is suitable for lightweight building structures, industrial corrosion-resistant materials, and decorative materials, and combines high strength, lightweight, and environmentally friendly characteristics.

[0006] According to a first embodiment of the present invention, a high-strength Zn-Cu-Ti alloy plate is provided.

[0007] The method for preparing the high-strength Zn-Cu-Ti alloy plate described in the first embodiment includes the following steps:

[0008] (1) Intermediate alloy smelting

[0009] (101) Ingredients: The mass percentage of the intermediate alloy is controlled as follows: Cu 2%~3.4%, Ti 2%~3%, with the balance being zinc;

[0010] (102) Smelting: Pure zinc is placed in a resistance smelting furnace and heated to 480℃~500℃ and held for 30min~45min; then, sponge titanium sheets and copper sheets are pressed into the zinc melt using a graphite bell jar, the temperature of the smelting furnace is raised to 700℃~800℃, stirred thoroughly, and held for 2h~3h. Then, the temperature is lowered to 540~600℃, and after slag removal, the molten metal is poured into a metal mold to obtain a Zn-Cu-Ti master alloy.

[0011] (2) Liquid extrusion

[0012] (201) The alloy raw materials are dried and preheated by holding them at 100℃~150℃ for 15min~30min. The alloy raw materials include zinc ingots, sponge titanium sheets, copper sheets, magnesium blocks and aluminum foil. Before melting, the resistance melting furnace is evacuated to a vacuum degree of -0.1MPa. Then, high-purity argon gas is continuously introduced, and zinc blocks, intermediate alloy and magnesium blocks are added to the melting furnace.

[0013] (202) Raise the temperature of the melting furnace to 600℃~650℃, stir thoroughly, and keep warm for 1h~2h, and then remove slag; lower the melting temperature to 500℃~600℃ and keep warm for 15min~30min; control the residence time before pressurization to 20s~60s, and then directly inject the melted liquid metal into the preheated extrusion die for extrusion. Control the die temperature to 100℃~250℃, the specific pressure to 60MPa~150MPa, and the pressing rate to 4mm / s~6mm / s to obtain a Zn-Cu-Ti alloy slab with a thickness of 6mm~10mm and a width of 100mm~150mm;

[0014] (3) Mechanical milling

[0015] The slab is milled on a milling machine, with four sides milled and the milling thickness set to 1.0mm to 1.5mm.

[0016] (4) Hot rolling and warm rolling

[0017] (401) Place the slab into the box-type resistance furnace and heat it to 180℃~250℃ with the furnace, and then keep it at that temperature for 45min~90min.

[0018] (402) The heated slab is hot rolled in a single pass on a hot rolling mill, with a rolling deformation of 30% to 45%.

[0019] (403) Then immediately carry out single-pass warm rolling, with the warm rolling temperature controlled at 80℃~120℃, the rolling deformation amount being 30%~45%, and the total deformation amount of hot rolling + warm rolling being 50%~70%.

[0020] (5) Composite straightening rolling

[0021] A tension straightener is installed between the rolling mill, coiling mill, and uncoiler, with the additional maximum tension controlled at 30-40 MPa;

[0022] The slab is subjected to multiple cold rolling passes while being tension straightened. The deformation amount of each rolling pass is 20% to 30%, and the total deformation amount is controlled at 75% to 95%. After each cold rolling pass, coolant is added to cool the mill and the plate, and the plate temperature is controlled at 10℃ to 30℃. After rolling, the plate is coiled. The thickness of the prepared Zn-Cu-Ti alloy coil is 0.68mm to 0.90mm.

[0023] (6) Annealing treatment

[0024] The Zn-Cu-Ti alloy coil is placed inside the heat-resistant inner shroud of the bell-shaped annealing furnace. An outer shroud with a heating element is installed on the outer shroud. The furnace is heated to 160℃~180℃ to ensure uniform temperature in all areas of the shroud. The temperature is held for 90min~120min. After annealing, the outer shroud is opened and the inner shroud is cooled by fan. When the furnace charge temperature is 50℃~80℃, the furnace charge is removed and air-cooled to room temperature.

[0025] (7) Cutting

[0026] The Zn-Cu-Ti alloy coil is sheared on both sides using a slitting machine, and the width after shearing is controlled between 100mm and 120mm.

[0027] (8) Pickling and degreasing cleaning

[0028] (801) The Zn-Cu-Ti alloy coil is cleaned with 5% to 10% hydrochloric acid. The pickling solution temperature is set to 30℃ to 60℃ and the pickling time is 5 min to 15 min.

[0029] (802) Then degreasing and cleaning are performed to remove the emulsion on the surface of the product. Degreasing is carried out using an alkaline degreasing agent. After completion, the product is washed with water in hot water at 50℃~80℃ and cold water at 10~20℃ respectively, and finally dried with hot air.

[0030] Preferably, in step (2), the melting temperature is 540-560℃ and the specific pressure is 80MPa-120MPa.

[0031] According to a third embodiment of the present invention, an application of a high-strength Zn-Cu-Ti alloy plate is provided.

[0032] According to the application of the high-strength Zn-Cu-Ti alloy sheet prepared by the method described in the second embodiment, the high-strength Zn-Cu-Ti alloy sheet is used as a building roof structure material after being passivated.

[0033] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0034] (1) By using liquid extrusion technology, the high melting point Cu and Ti phases are forced to dissolve in the zinc matrix under high pressure. Compared with the traditional casting process, which causes severe segregation of Cu and Ti elements in Zn-Cu-Ti alloy, liquid extrusion technology can effectively eliminate the problem of component segregation and make the Zn-Cu-Ti alloy component distribution uniform.

[0035] (2) By adding trace amounts of Al (0.005% to 0.01%) and Mg (0.005% to 0.008%) to adjust the alloy composition, combined with the synergistic effect of solid solution strengthening and dispersed phases (CuZn4, TiZn3), a balance between high strength and plasticity was achieved compared with the traditional scheme.

[0036] (3) Through composite straightening rolling technology, hot rolling, warm rolling and multiple cold rolling processes are completed in one step, while 30-40MPa tension is applied to straighten the plate. This integrates multiple processes, effectively simplifies the production process of Zn-Cu-Ti alloy plates, and improves the plate production efficiency.

[0037] (4) Through low alloying design, the Cu and Ti contents are controlled at 0.1% to 0.17%, and the raw material cost is reduced and the production efficiency is improved without changing the performance.

[0038] (5) Through liquid extrusion technology, only intermediate alloys need to be prepared, which effectively reduces smelting energy consumption and smelting waste gas emissions. Combined with composite straightening technology, the surface of the rolled plate is smoother and flatter, which greatly saves the solution consumption for pickling and degreasing treatment, and is more in line with the trend of green manufacturing. Attached Figure Description

[0039] Figure 1 This is a process flow diagram of the present invention;

[0040] Figure 2 This is a schematic diagram of the composite straightening rolling process of the present invention;

[0041] Figure 3 Here is a SEM image of the RD-ND surface of the finished Zn-Cu-Ti plate from Comparative Example 1.

[0042] Figure 4 This is a SEM image of the RD-ND surface of the finished Zn-Cu-Ti plate from Example 2. Detailed Implementation

[0043] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments.

[0044] Comparative Example 1

[0045] I. Pretreatment before smelting and rolling

[0046] The alloy composition is designed to consist of 0.17% Cu, 0.15% Ti, 0.01% Al, 0.008% Mg and the balance Zn by mass percentage, wherein the mass fraction of impurities is ≤0.1%.

[0047] II. Intermediate Alloy Melting

[0048] 1. Ingredients: The mass percentage of the intermediate alloy composition is controlled as follows: Cu 3.4%, Ti 3.0%, with the balance being zinc;

[0049] 2. Smelting: Pure zinc is placed in a resistance smelting furnace and heated to 500℃, and held for 30 minutes. Then, a graphite bell jar is used to press sponge titanium sheets and copper sheets into the zinc melt. The temperature of the smelting furnace is raised to 750℃, stirred thoroughly, and held for 2 hours. Then, the temperature is lowered to 550℃. After removing the slag, the molten metal is poured into a metal mold to obtain an intermediate alloy.

[0050] III. Alloy Smelting

[0051] 1. Place pure zinc in a resistance melting furnace, heat to 500℃, and hold for 30 minutes; then press the Zn-Cu-Ti intermediate alloy obtained in step two into the zinc melt using a graphite bell jar, set the melting temperature to 700℃, stir thoroughly, and let stand for 2 hours.

[0052] 2. Reduce the furnace temperature to 550℃, remove the slag, and pour the molten metal into a metal mold to obtain the final Zn-Cu-Ti alloy.

[0053] IV. Mechanical Milling

[0054] The slab is milled on a milling machine, with four sides milled and a milling thickness of 1mm. After milling, a slab with a thickness of 6mm and a width of 120mm is obtained.

[0055] V. Composite straightening rolling

[0056] 1. Hot rolling: The slab is placed in a box-type resistance furnace and heated to 200°C, and then held at that temperature for 60 minutes; the heated slab is then hot rolled in a single pass on a hot rolling mill, with a rolling deformation of 30%.

[0057] 2. Warm rolling: Then immediately carry out single-pass warm rolling, with the temperature controlled at 100℃ and the rolling deformation amount of 30%. The total deformation amount of hot rolling + warm rolling is 51%, and a slab with a thickness of 2.94mm is obtained.

[0058] 3. Composite straightening rolling: A tension straightener is set up between the rolling mill, coiling mill, and uncoiler, with the maximum additional tension controlled at 40MPa; the slab is subjected to multiple passes of cold rolling while being tension straightened, with a deformation of 25% per pass and a total deformation of 76.27%. Cooling liquid is added after each pass of cold rolling to cool the rolling mill and the plate, and the plate temperature is controlled at 20℃. After rolling, the plate is coiled, and the thickness of the prepared Zn-Cu-Ti alloy coil is 0.70mm.

[0059] VI. Post-rolling treatment

[0060] 1. Annealing treatment: Place the Zn-Cu-Ti alloy coil into the heat-resistant inner shroud of the bell-type annealing furnace. Install an outer shroud with a heating element on the outer shroud. Heat to 160℃, ensuring uniform temperature in all areas of the shroud. Hold for 120 minutes. After annealing, open the outer shroud and use a fan to force-cool the inner shroud. When the furnace charge temperature is 50℃, remove the charge from the furnace and air-cool to room temperature.

[0061] 2. Cutting: Use a slitting machine to cut both sides of the Zn-Cu-Ti alloy coil. The width after cutting is controlled to be 100mm.

[0062] VII. Pickling and degreasing cleaning: The Zn-Cu-Ti alloy coil is cleaned with 5% hydrochloric acid at a temperature of 50℃ for 5 minutes. Then, degreasing cleaning is performed to remove the emulsion on the surface of the product. Alkaline degreasing agent is used for degreasing. After completion, the product is washed with water at 50℃ and then in cold water at 20℃. Finally, it is dried with hot air.

[0063] Table 1 shows the mechanical properties of Zn-Cu-Ti.

[0064] Table 1

[0065]

[0066] Comparative Example 2

[0067] I. Pretreatment before smelting and rolling

[0068] The alloy composition is designed to consist of 0.17% Cu, 0.15% Ti, 0.01% Al, 0.008% Mg and the balance Zn by mass percentage, wherein the mass fraction of impurities is ≤0.1%.

[0069] II. Intermediate Alloy Melting

[0070] 1. Ingredients: The mass percentage of the intermediate alloy composition is controlled as follows: Cu 3.4%, Ti 3.0%, with the balance being zinc;

[0071] 2. Smelting: Pure zinc is placed in a resistance smelting furnace and heated to 500℃, and held for 30 minutes. Then, a graphite bell jar is used to press sponge titanium sheets and copper sheets into the zinc melt. The temperature of the smelting furnace is raised to 750℃, stirred thoroughly, and held for 2 hours. Then, the temperature is lowered to 550℃. After removing the slag, the molten metal is poured into a metal mold to obtain an intermediate alloy.

[0072] III. Liquid Extrusion

[0073] 1. Dry and preheat the alloy raw materials by holding them at 100℃ for 30 minutes;

[0074] 2. The alloy raw materials include zinc ingots, sponge titanium sheets, copper sheets, magnesium blocks and aluminum foil. Before smelting, the resistance melting furnace is evacuated to a vacuum degree of -0.1 MPa.

[0075] 3. Then, high-purity argon gas is continuously introduced, and zinc blocks, intermediate alloys, and magnesium blocks are added to the melting furnace;

[0076] 4. Raise the temperature of the smelting furnace to 600℃, stir thoroughly, and keep warm for 2 hours before removing the slag;

[0077] 5. Reduce the melting temperature to 540℃ and hold for 30 minutes; control the dwell time before pressurization to 30 seconds, then directly inject the melted liquid metal into the preheated extrusion die for extrusion. Control the die temperature to 150℃, the specific pressure to 100MPa, and the pressing rate to 5mm / s to obtain a Zn-Cu-Ti alloy slab with a thickness of 8mm and a width of 122mm.

[0078] IV. Mechanical Milling

[0079] The slab is milled on a milling machine, with four sides milled and a milling thickness of 1mm. After milling, a slab with a thickness of 6mm and a width of 120mm is obtained.

[0080] V. Rolling

[0081] 1. Hot rolling: The slab is placed in a box-type resistance furnace and heated to 200°C, and then held at that temperature for 60 minutes; the heated slab is then hot rolled in a single pass on a hot rolling mill, with a rolling deformation of 30%.

[0082] 2. Warm rolling: Then immediately carry out single-pass warm rolling, with the temperature controlled at 100℃ and the rolling deformation amount of 30%. The total deformation amount of hot rolling + warm rolling is 51%, and a slab with a thickness of 2.94mm is obtained.

[0083] 3. Cold rolling: Subsequently, multiple cold rolling passes were immediately carried out. The cold rolling temperature was controlled at 20℃, the rolling deformation was 25%, the total cold rolling deformation was 76%, and the thickness of the prepared Zn-Cu-Ti alloy coil was 0.70mm.

[0084] VI. Post-rolling treatment

[0085] 1. Annealing treatment: Place the Zn-Cu-Ti alloy coil into the heat-resistant inner shroud of the bell-type annealing furnace. Install an outer shroud with a heating element on the outer shroud. Heat to 160℃, ensuring uniform temperature in all areas of the shroud. Hold for 120 minutes. After annealing, open the outer shroud and use a fan to force-cool the inner shroud. When the furnace charge temperature is 50℃, remove the charge from the furnace and air-cool to room temperature.

[0086] 2. Cutting: Use a slitting machine to cut both sides of the Zn-Cu-Ti alloy coil. The width after cutting is controlled to be 100mm.

[0087] VII. Pickling and degreasing cleaning: The Zn-Cu-Ti alloy coil is cleaned with 5% hydrochloric acid at a temperature of 50℃ for 5 minutes. Then, degreasing cleaning is performed to remove the emulsion on the surface of the product. Alkaline degreasing agent is used for degreasing. After completion, the product is washed with water at 50℃ and then in cold water at 20℃. Finally, it is dried with hot air.

[0088] Table 2 shows the mechanical properties of Zn-Cu-Ti.

[0089] Table 2

[0090]

[0091] Example 1

[0092] I. Pretreatment before smelting and rolling

[0093] The alloy composition is designed to consist of 0.17% Cu, 0.15% Ti, 0.01% Al, 0.008% Mg and the balance Zn by mass percentage, wherein the mass fraction of impurities is ≤0.1%.

[0094] II. Intermediate Alloy Melting

[0095] 1. Ingredients: The mass percentage of the intermediate alloy composition is controlled as follows: Cu 3.4%, Ti 3.0%, with the balance being zinc;

[0096] 2. Smelting: Pure zinc is placed in a resistance smelting furnace and heated to 500℃, and held for 30 minutes. Then, a graphite bell jar is used to press sponge titanium sheets and copper sheets into the zinc melt. The temperature of the smelting furnace is raised to 750℃, stirred thoroughly, and held for 2 hours. Then, the temperature is lowered to 550℃. After removing the slag, the molten metal is poured into a metal mold to obtain an intermediate alloy.

[0097] III. Liquid Extrusion

[0098] 1. Dry and preheat the alloy raw materials by holding them at 100℃ for 30 minutes;

[0099] 2. The alloy raw materials include zinc ingots, sponge titanium sheets, copper sheets, magnesium blocks and aluminum foil. Before smelting, the resistance melting furnace is evacuated to a vacuum degree of -0.1 MPa.

[0100] 3. Then, high-purity argon gas is continuously introduced, and zinc blocks, intermediate alloys, and magnesium blocks are added to the melting furnace;

[0101] 4. Raise the temperature of the smelting furnace to 600℃, stir thoroughly, and keep warm for 2 hours before removing the slag;

[0102] 5. Reduce the melting temperature to 540℃ and hold for 30 minutes; control the dwell time before pressurization to 30 seconds, then directly inject the melted liquid metal into the preheated extrusion die for extrusion. Control the die temperature to 150℃, the specific pressure to 100MPa, and the pressing rate to 5mm / s to obtain a Zn-Cu-Ti alloy slab with a thickness of 8mm and a width of 122mm.

[0103] IV. Mechanical Milling

[0104] The slab is milled on a milling machine, with four sides milled and a milling thickness of 1mm. After milling, a slab with a thickness of 6mm and a width of 120mm is obtained.

[0105] V. Composite straightening rolling

[0106] 1. Hot rolling: The slab is placed in a box-type resistance furnace and heated to 200°C, and then held at that temperature for 60 minutes; the heated slab is then hot rolled in a single pass on a hot rolling mill, with a rolling deformation of 30%.

[0107] 2. Warm rolling: Then immediately carry out single-pass warm rolling, with the temperature controlled at 100℃ and the rolling deformation amount of 30%. The total deformation amount of hot rolling + warm rolling is 51%, and a slab with a thickness of 2.94mm is obtained.

[0108] 3. Composite straightening rolling: A tension straightener is set up between the rolling mill, coiling mill, and uncoiler, with the maximum additional tension controlled at 40MPa; the slab is subjected to multiple passes of cold rolling while being tension straightened, with a deformation of 25% per pass and a total deformation of 76.27%. Cooling liquid is added after each pass of cold rolling to cool the rolling mill and the plate, and the plate temperature is controlled at 20℃. After rolling, the plate is coiled, and the thickness of the prepared Zn-Cu-Ti alloy coil is 0.70mm.

[0109] VI. Post-rolling treatment

[0110] 1. Annealing treatment: Place the Zn-Cu-Ti alloy coil into the heat-resistant inner shroud of the bell-type annealing furnace. Install an outer shroud with a heating element on the outer shroud. Heat to 160℃, ensuring uniform temperature in all areas of the shroud. Hold for 120 minutes. After annealing, open the outer shroud and use a fan to force-cool the inner shroud. When the furnace charge temperature is 50℃, remove the charge from the furnace and air-cool to room temperature.

[0111] 2. Cutting: Use a slitting machine to cut both sides of the Zn-Cu-Ti alloy coil. The width after cutting is controlled to be 100mm.

[0112] VII. Pickling and degreasing cleaning: The Zn-Cu-Ti alloy coil is cleaned with 5% hydrochloric acid at a temperature of 50℃ for 5 minutes. Then, degreasing cleaning is performed to remove the emulsion on the surface of the product. Alkaline degreasing agent is used for degreasing. After completion, the product is washed with water at 50℃ and then in cold water at 20℃. Finally, it is dried with hot air.

[0113] Table 3 shows the mechanical properties of Zn-Cu-Ti.

[0114] Table 3

[0115]

[0116] Example 2

[0117] I. Pretreatment before smelting and rolling

[0118] Pre-smelting and rolling treatment: Design the alloy composition, which consists of 0.15% Cu, 0.12% Ti, 0.01% Al, 0.008% Mg and balance Zn by mass percentage, wherein the mass fraction of impurities is ≤0.1%.

[0119] II. Intermediate Alloy Melting

[0120] 1. Ingredients: The mass percentage of the intermediate alloy composition is controlled as follows: Cu 3.4%, Ti 3.0%, with the balance being zinc;

[0121] 2. Smelting: Pure zinc is placed in a resistance smelting furnace and heated to 500℃, and held for 30 minutes. Then, a graphite bell jar is used to press sponge titanium sheets and copper sheets into the zinc melt. The temperature of the smelting furnace is raised to 750℃, stirred thoroughly, and held for 2 hours. Then, the temperature is lowered to 550℃. After removing the slag, the molten metal is poured into a metal mold to obtain an intermediate alloy.

[0122] III. Liquid Extrusion

[0123] 1. Dry and preheat the alloy raw materials by holding them at 100℃ for 30 minutes;

[0124] 2. The alloy raw materials include zinc ingots, sponge titanium sheets, copper sheets, magnesium blocks, and aluminum foil. Before smelting, the resistance melting furnace is evacuated to a vacuum level of -0.1 MPa.

[0125] 3. Then, high-purity argon gas is continuously introduced, and zinc blocks, intermediate alloys, and magnesium blocks are added to the melting furnace;

[0126] 4. Raise the temperature of the smelting furnace to 600℃, stir thoroughly, and keep warm for 2 hours before removing the slag;

[0127] 5. Reduce the melting temperature to 550℃ and hold for 30 minutes; control the dwell time before pressurization to 30 seconds, then directly inject the melted liquid metal into the preheated extrusion die for extrusion. Control the die temperature to 150℃, the specific pressure to 100MPa, and the pressing rate to 5mm / s to obtain a Zn-Cu-Ti alloy slab with a thickness of 8mm and a width of 122mm.

[0128] IV. Mechanical Milling

[0129] The slab is milled on a milling machine, with four sides milled and a milling thickness of 1mm. After milling, a slab with a thickness of 6mm and a width of 120mm is obtained.

[0130] V. Composite straightening rolling

[0131] 1. Hot rolling: The slab is placed in a box-type resistance furnace and heated to 200°C, and then held at that temperature for 60 minutes; the heated slab is then hot rolled in a single pass on a hot rolling mill, with a rolling deformation of 30%.

[0132] 2. Warm rolling: Then immediately carry out single-pass warm rolling, with the temperature controlled at 100℃ and the rolling deformation amount of 30%. The total deformation amount of hot rolling + warm rolling is 51%, and a slab with a thickness of 2.94mm is obtained.

[0133] 3. Composite straightening rolling: A tension straightener is set up between the rolling mill, coiling mill, and uncoiler, with the maximum additional tension controlled at 40MPa; the slab is subjected to multiple passes of cold rolling while being tension straightened, with a deformation of 25% per pass and a total deformation of 76.27%. Cooling liquid is added after each pass of cold rolling to cool the rolling mill and the plate, and the plate temperature is controlled at 20℃. After rolling, the plate is coiled, and the thickness of the prepared Zn-Cu-Ti alloy coil is 0.70mm.

[0134] VI. Post-rolling treatment

[0135] 1. Annealing treatment: Place the Zn-Cu-Ti alloy coil into the heat-resistant inner shroud of the bell-type annealing furnace. Install an outer shroud with a heating element on the outer shroud. Heat to 160℃, ensuring uniform temperature in all areas of the shroud. Hold for 120 minutes. After annealing, open the outer shroud and use a fan to force-cool the inner shroud. When the furnace charge temperature is 50℃, remove the charge from the furnace and air-cool to room temperature.

[0136] 2. Cutting: Use a slitting machine to cut both sides of the Zn-Cu-Ti alloy coil. The width after cutting is controlled to be 100mm.

[0137] VII. Pickling and degreasing cleaning: The Zn-Cu-Ti alloy coil is cleaned with 5% hydrochloric acid at a temperature of 50℃ for 5 minutes. Then, degreasing cleaning is performed to remove the emulsion on the surface of the product. Alkaline degreasing agent is used for degreasing. After completion, the product is washed with water at 50℃ and then in cold water at 20℃. Finally, it is dried with hot air.

[0138] Table 4 shows the mechanical properties of Zn-Cu-Ti.

[0139] Table 4

[0140]

[0141] Example 3

[0142] I. Pretreatment before smelting and rolling

[0143] Pre-smelting and rolling treatment: Design the alloy composition, which consists of 0.15% Cu, 0.12% Ti, 0.01% Al, 0.008% Mg and balance Zn by mass percentage, wherein the mass fraction of impurities is ≤0.1%.

[0144] II. Intermediate Alloy Melting

[0145] 1. Ingredients: The mass percentage of the intermediate alloy composition is controlled as follows: Cu 3.4%, Ti 3.0%, with the balance being zinc;

[0146] 2. Smelting: Pure zinc is placed in a resistance smelting furnace and heated to 500℃, and held for 30 minutes. Then, a graphite bell jar is used to press sponge titanium sheets and copper sheets into the zinc melt. The temperature of the smelting furnace is raised to 750℃, stirred thoroughly, and held for 2 hours. Then, the temperature is lowered to 550℃. After removing the slag, the molten metal is poured into a metal mold to obtain an intermediate alloy.

[0147] III. Liquid Extrusion

[0148] 1. Dry and preheat the alloy raw materials by holding them at 100℃ for 30 minutes;

[0149] 2. The alloy raw materials include zinc ingots, sponge titanium sheets, copper sheets, magnesium blocks, and aluminum foil. Before smelting, the resistance melting furnace is evacuated to a vacuum level of -0.1 MPa.

[0150] 3. Then, high-purity argon gas is continuously introduced, and zinc blocks, intermediate alloys, and magnesium blocks are added to the melting furnace;

[0151] 4. Raise the temperature of the smelting furnace to 600℃, stir thoroughly, and keep warm for 2 hours before removing the slag;

[0152] 5. Reduce the melting temperature to 550℃ and hold for 30 minutes; control the dwell time before pressurization to 30 seconds, then directly inject the melted liquid metal into the preheated extrusion die for extrusion. Control the die temperature to 150℃, the specific pressure to 100MPa, and the pressing rate to 5mm / s to obtain a Zn-Cu-Ti alloy slab with a thickness of 8mm and a width of 122mm.

[0153] IV. Mechanical Milling

[0154] The slab is milled on a milling machine, with four sides milled and a milling thickness of 1mm. After milling, a slab with a thickness of 6mm and a width of 120mm is obtained.

[0155] V. Composite straightening rolling

[0156] 1. Hot rolling: The slab is placed in a box-type resistance furnace and heated to 200°C, and then held at that temperature for 60 minutes; the heated slab is then hot rolled in a single pass on a hot rolling mill, with a rolling deformation of 30%.

[0157] 2. Warm rolling: Then immediately carry out single-pass warm rolling, with the temperature controlled at 100℃ and the rolling deformation amount of 30%. The total deformation amount of hot rolling + warm rolling is 51%, and a slab with a thickness of 2.94mm is obtained.

[0158] 3. Composite straightening rolling: A tension straightener is set up between the rolling mill, coiling mill, and uncoiler, with the maximum additional tension controlled at 40MPa; the slab is subjected to multiple passes of cold rolling while being tension straightened, with a deformation of 25% per pass and a total deformation of 76.27%. Cooling liquid is added after each pass of cold rolling to cool the rolling mill and the plate, and the plate temperature is controlled at 20℃. After rolling, the plate is coiled, and the thickness of the prepared Zn-Cu-Ti alloy coil is 0.70mm.

[0159] VI. Post-rolling treatment

[0160] 1. Annealing treatment: Place the Zn-Cu-Ti alloy coil into the heat-resistant inner shroud of the bell-type annealing furnace. Install an outer shroud with a heating element on the outer shroud. Heat to 160℃, ensuring uniform temperature in all areas of the shroud. Hold for 120 minutes. After annealing, open the outer shroud and use a fan to force-cool the inner shroud. When the furnace charge temperature is 50℃, remove the charge from the furnace and air-cool to room temperature.

[0161] 2. Cutting: Use a slitting machine to cut both sides of the Zn-Cu-Ti alloy coil. The width after cutting is controlled to be 100mm.

[0162] VII. Pickling and degreasing cleaning: The Zn-Cu-Ti alloy coil is cleaned with 5% hydrochloric acid at a temperature of 50℃ for 5 minutes. Then, degreasing cleaning is performed to remove the emulsion on the surface of the product. Alkaline degreasing agent is used for degreasing. After completion, the product is washed with water at 50℃ and then in cold water at 20℃. Finally, it is dried with hot air.

[0163] Table 5 shows the mechanical properties of Zn-Cu-Ti.

[0164] Table 5

[0165]

[0166] from Figure 3 and Figure 4 It can be seen that the alloy phase precipitation in the alloy material prepared in Example 2 of the present invention is more uniform and the microstructure is more superior.

Claims

1. A high-strength zinc-copper-titanium (Zn-Cu-Ti) alloy sheet, characterized in that, The composition by mass percentage is: copper (Cu) 0.1%–0.17%, titanium (Ti) 0.1%–0.15%, aluminum (Al) 0.005%–0.01%, magnesium (Mg) 0.005%–0.008%, with the balance being zinc (Zn, purity ≥99.99%), and impurities ≤0.1%.

2. The method for preparing Zn-Cu-Ti alloy plate according to claim 1, characterized in that, Includes the following steps: (1) Smelting of intermediate alloy: Smelting copper, titanium and zinc into an intermediate alloy, the composition of which is Cu 2% to 3.4%, Ti 2% to 3%, balance Zn; (2) Liquid extrusion: Under vacuum argon protection, the alloy raw material is melted and injected into a preheated mold for extrusion. The mold temperature is 100℃~250℃ and the specific pressure is 60~150MPa to obtain a slab with a thickness of 6~10mm. (3) Composite straightening rolling: The slab is subjected to hot rolling (30% to 45% deformation), warm rolling (30% to 45% deformation) and multiple cold rolling passes (75% to 95% total deformation) in sequence, while simultaneously applying a tension of 30 to 40 MPa for straightening. (4) Annealing treatment: The rolled sheet is kept at 160℃~180℃ for 90~120 minutes, and then cooled to room temperature.

3. The preparation method according to claim 2, characterized in that, The melting temperature of the liquid extrusion is 600℃~650℃, and the holding time is 1~2 hours.

4. The preparation method according to claim 2, characterized in that, In the composite straightening rolling process, the deformation amount per cold rolling pass is 20% to 30%, and the temperature of the plate is controlled at 10℃ to 30℃ by the coolant. According to the preparation method of claim 2, the annealing treatment is carried out in a bell-type annealing furnace, and after annealing, the plate is pickled (5% to 10% hydrochloric acid, 30°C to 60°C) and degreased.

5. The Zn-Cu-Ti alloy plate according to any one of claims 1-5, characterized in that, Its tensile strength is ≥155MPa, elongation is ≥26%, and Vickers hardness is 45~47HV.

6. The application of the Zn-Cu-Ti alloy sheet according to any one of claims 1-6 in lightweight building structural materials, industrial corrosion-resistant sheets or decorative materials.

Images