Method for preparing high-performance two-phase titanium alloy at low cost by electron beam cooling hearth furnace melting flat ingot process

Abstract

The present invention relates to the field of titanium alloy smelting technology and discloses a method for preparing a high-performance two-phase titanium alloy at low cost by melting flat ingots in an electron beam cooling hearth furnace. The method comprises a two-phase titanium alloy, wherein the nominal composition of the two-phase titanium alloy is proportioned, with TC4 titanium alloy return material as the main material, supplemented by an intermediate compensating alloy, and an improved charging method. Subsequently, an electron beam cooling hearth furnace is used to melt the two-phase titanium alloy ingot. The present invention uses TC4 titanium alloy return material as the main material and melts the two-phase titanium alloy ingot in an electron beam cooling hearth furnace to produce a directly rolled two-phase titanium alloy ingot, eliminating the subsequent blanking and forging process. This not only reduces raw material costs but also shortens the process flow, thereby achieving the goal of low-cost production of the two-phase titanium alloy.

Description

Technical Field

[0001] The invention relates to the technical field of titanium alloy smelting, and in particular to a method for preparing a high-performance two-phase titanium alloy at low cost by using an electron beam cooling hearth furnace to melt a flat ingot. Background Art

[0002] In recent years, with the development and implementation of technologies in fields such as marine engineering, advanced transportation, and energy equipment, the performance requirements for high-performance alloy materials have become increasingly higher. Due to the harsh service environment of alloys, titanium alloys with excellent comprehensive properties such as high strength and toughness, low density, and high corrosion resistance have become one of the most ideal materials. However, the cost of domestic titanium alloy plates remains high, and how to effectively reduce the cost of titanium alloy plates has become an urgent problem to be solved.

[0003] Chinese Patent Publication No. CN116397132A discloses a high-performance, low-cost two-phase titanium alloy. By utilizing a large amount of TC4 titanium alloy return material supplemented with a small amount of intermediate alloy, a low-cost titanium alloy with excellent performance can be obtained, effectively reducing the production cost of titanium alloy plates. However, the titanium alloy ingots obtained after smelting by this technology need to be subjected to blanking forging and solid solution aging treatment, which is a relatively complicated process and the production cost of titanium alloy plates is still relatively high. The present invention eliminates the subsequent blanking forging process, which not only reduces the raw material cost, but also shortens the process flow and reduces production costs.

[0004] Chinese Patent Publication No. CN 118109696 A discloses a process for melting flat ingots from TC4 titanium alloy block return material in an electron beam cold hearth furnace. The process comprises selecting titanium sponge, TC4 titanium alloy block return material, aluminum peas, and aluminum-vanadium alloy as raw materials. Based on the composition of the TC4 titanium alloy block return material, the aluminum peas, aluminum-vanadium alloy, and titanium sponge are mixed and briquetted in a certain proportion. The briquetized TC4 alloy material and the TC4 titanium alloy block return material are then loaded into an electron beam cold hearth furnace for evacuation and smelting to obtain TC4 alloy flat ingots. This technology can reduce carbon emissions and production costs and achieve the recycling of titanium resources. However, this technology is primarily for the production of TC4 titanium alloy and does not provide detailed descriptions of the raw material ratio, material distribution method, and power control during the melting process. Therefore, the technology is not suitable for the preparation of the two-phase titanium alloy of the present invention and cannot achieve the purpose of low-cost production of the two-phase titanium alloy. Summary of the Invention

[0005] In view of the defects existing in the prior art, the purpose of the present invention is to provide a method for preparing high-performance two-phase titanium alloy at low cost by melting flat ingots in an electron beam cooling hearth furnace. TC4 titanium alloy return material is used as the main material, supplemented by an intermediate compensation alloy, and two-phase titanium alloy ingots that can be directly rolled are melted in an electron beam cooling hearth furnace, eliminating the subsequent blanking and forging process, which not only reduces the raw material cost but also shortens the process flow, thereby achieving the purpose of low-cost production of two-phase titanium alloy.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for preparing a high-performance two-phase titanium alloy at low cost by melting a flat ingot in an electron beam cooling hearth furnace, comprising the following steps:

[0008] S1, according to the nominal composition of the two-phase titanium alloy, calculate the amount of TC4 titanium alloy return material, sponge titanium, aluminum vanadium alloy, ferrochrome alloy, aluminum beans, and titanium ferroalloy and weigh them, and control the addition amount of TC4 titanium alloy return material to be ≥50%;

[0009] S2, dividing the titanium sponge into two parts, mixing one part of the titanium sponge with aluminum-vanadium alloy, aluminum bean, and titanium-iron alloy and briquetting to obtain a first briquette material, and mixing the other part of the titanium sponge with chromium-iron alloy and briquetting to obtain a second briquette material;

[0010] S3, drying the first briquetting material and the second briquetting material;

[0011] S4, loading the dried first compacted material into the bottom layer of the material box of the electron beam cooling hearth furnace, loading the TC4 titanium alloy return material into the second layer, and loading the second compacted material onto the top of the TC4 titanium alloy return material;

[0012] S5, after the furnace is loaded, the electron beam cooling furnace is sealed, and after leak detection, vacuum is evacuated until the vacuum degree in the electron beam cooling furnace reaches 1 Pa, and then the gun is preheated;

[0013] S6, open the 1# electron gun, 2# electron gun, 3# electron gun, and 4# electron gun in the cooling bed for heating. When the liquid level in the cooling bed is higher than the overflow port, open the 5# electron gun for heating. When the titanium liquid in the cooling bed flows into the crystallizer, open the 6# electron gun and 7# electron gun for heating;

[0014] S7, when the titanium liquid fills the crystallizer, increase the power of the 6# electron gun and the 7# electron gun until the titanium liquid fills the entire crystallizer, then start melting and pulling the ingot;

[0015] S8, after the melting and casting is completed, the tail of the ingot is subjected to shrinkage feeding, and then cooled. After cooling, the electron beam cooling furnace is opened, and the two-phase titanium alloy ingot is taken out from the crystallizer.

[0016] Preferably, in step S1:

[0017] The nominal composition of the two-phase titanium alloy is Ti-(6.90-7.60)Al-(3.90-4.10)V-(1.30-1.65)Cr-(0.90-1.10)Fe;

[0018] The added amount of the TC4 titanium alloy return material is 50% to 80%.

[0019] Preferably, in step S2, the titanium sponge used in the first compacted material accounts for 50-60% of the total amount of the titanium sponge.

[0020] Preferably, in the step S3, during the drying process, the drying temperature is 150-180° C., and the drying time is 2-4 hours.

[0021] Preferably, in step S4, the material layer heights of the first pressed block material and the second pressed block material are 110-140 mm, and the material layer height of the TC4 titanium alloy return material is 300-500 mm.

[0022] Preferably, in step S6, the power of the 1# electron gun, the 2# electron gun, the 3# electron gun, and the 4# electron gun is 100-150 kW, the power of the 5# electron gun is 100-130 kW, and the heating power of the 6# electron gun and the 7# electron gun is 100-180 kW.

[0023] Preferably, in step S7, the power of the 6# electron gun and the 7# electron gun is increased to 240-300 kW.

[0024] Preferably, in step S7:

[0025] During the melting and casting process, the power of the 1# electron gun, 2# electron gun, 3# electron gun, 4# electron gun, 5# electron gun, 6# electron gun, and 7# electron gun is adjusted to ensure that the melting speed of the material matches the ingot pulling speed;

[0026] During the melting and casting process, the vacuum degree of the electron beam cooling furnace is controlled at 0.5~3Pa;

[0027] During the casting process, the liquid level in the crystallizer is controlled to be 5 to 30 mm from the edge of the crystallizer;

[0028] During the ingot pulling process, the flow rate of the titanium liquid into the crystallizer is kept matching the ingot pulling speed;

[0029] The ingot pulling speed is controlled at 300-500 mm / h.

[0030] Preferably, in step S7, during the melting and casting process, the power of the 1# electron gun, the 2# electron gun, the 3# electron gun, and the 4# electron gun is 150-300 kW, the power of the 5# electron gun is 100-130 kW, and the power of the 6# electron gun and the 7# electron gun is 240-300 kW.

[0031] Preferably, the composition of the two-phase titanium alloy ingot is as follows by mass percentage: Al 5.0% to 7.0%, V 3.0% to 5.0%, Cr 0.5% to 2.0%, Fe 0.5% to 1.5%, and the balance is Ti and unavoidable impurities;

[0032] The density of the two-phase titanium alloy ingot is 4.4-4.5 g / cm 3 , tensile strength ≥865 MPa, yield strength ≥825 MPa, impact toughness 40~50 J / cm 2 , the elongation is 8~11%.

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

[0034] The present invention uses TC4 titanium alloy return material as the main material, supplemented by an intermediate compensation alloy, and uses an electron beam cooling hearth furnace to melt a two-phase titanium alloy ingot that can be directly rolled, eliminating the subsequent blanking and forging process, reducing raw material costs while also shortening the process flow, thereby achieving the purpose of low-cost production of high-performance two-phase titanium alloy; the present invention uses TC4 titanium alloy return material as the main material, realizing the recycling of titanium resources; the present invention improves the loading method, placing the pressed sponge titanium, aluminum vanadium alloy, aluminum beans, and titanium-iron alloy pressed materials on the bottom layer of the material box, placing the TC4 titanium alloy return material on the second layer, and placing the sponge titanium and chromium-iron alloy pressed materials on the upper layer. Such a distribution method is conducive to reducing the loss of chromium in high-density, high-melting-point chromium-iron alloy, while reducing the volatilization of aluminum in low-melting-point aluminum vanadium alloy and aluminum beans. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a flow chart of the method for preparing high-performance two-phase titanium alloy at low cost by using electron beam cooling furnace melting flat ingot process of the present invention;

[0036] Figure 2 This is the layout diagram of the electron gun and crystallizer on the cooling bed;

[0037] Among them, 1. Push screw; 2. Push plate; 3. Material box; 4. Material; 5. Cooling bed; 6. Crystallizer; 7. 1# electron gun; 8. 2# electron gun; 9. 3# electron gun; 10. 4# electron gun; 11. 5# electron gun; 12. 6# electron gun; 13. 7# electron gun. DETAILED DESCRIPTION

[0038] The present invention will be described in detail below with reference to specific examples. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form.

[0039] The present invention uses TC4 titanium alloy return material, sponge titanium, aluminum-vanadium alloy, ferrochrome alloy, aluminum bean, and titanium-ferroalloy as raw materials, which can save about 10-20% of the cost compared with the traditional preparation process. It uses an electron beam cooling hearth furnace to melt two-phase titanium alloy ingots that can be directly rolled, shortening the process flow, reducing production costs, and realizing the recycling of titanium resources.

[0040] Combine Figure 1 、 Figure 2 As shown, the present invention provides a method for preparing a high-performance two-phase titanium alloy at low cost by melting a flat ingot in an electron beam cooling furnace, comprising the following steps:

[0041] S1, according to the nominal composition of the two-phase titanium alloy, calculate the amount of TC4 titanium alloy return material, sponge titanium, aluminum vanadium alloy, ferrochrome alloy, aluminum beans, and titanium ferroalloy and weigh them, and control the addition amount of TC4 titanium alloy return material to be ≥50%;

[0042] The purpose of this step is to proportion the raw materials. According to the nominal composition ratio of the two-phase titanium alloy: Ti-(6.90~7.60)Al-(3.90~4.10)V-(1.30~1.65)Cr-(0.90~1.10)Fe, the amount of TC4 titanium alloy return material, sponge titanium, aluminum vanadium alloy, ferrochrome alloy, aluminum bean, and titanium ferroalloy is calculated, and each raw material is weighed. When proportioning, the amount of TC4 titanium alloy return material added is controlled to be ≥50%, for example, the amount of TC4 titanium alloy return material added is 50%~80%;

[0043] In this step, TC4 titanium alloy return material is used as the main material, supplemented by intermediate compensation alloys, namely sponge titanium, aluminum vanadium alloy, ferrochrome alloy, aluminum beans, and ferrotitanium alloy. When preparing the ingredients, the components of TC4 titanium alloy return material, sponge titanium, aluminum vanadium alloy, ferrochrome alloy, aluminum beans, and ferrotitanium alloy can be tested first;

[0044] S2, dividing the titanium sponge into two parts, mixing one part of the titanium sponge with aluminum-vanadium alloy, aluminum bean, and titanium-iron alloy and briquetting to obtain a first briquette material, and mixing the other part of the titanium sponge with chromium-iron alloy and briquetting to obtain a second briquette material;

[0045] This step is mainly to process the raw materials. The sponge titanium used in the first briquette is 50-60% of the total amount of sponge titanium, and the sponge titanium used in the second briquette is the remaining sponge titanium.

[0046] S3, drying the first briquetting material and the second briquetting material;

[0047] This step is mainly to dry the first and second briquette materials at a temperature of 150-180°C for 2-4 hours.

[0048] S4, loading the dried first compacted material into the bottom layer of the material box 3 of the electron beam cooling hearth furnace, loading the TC4 titanium alloy return material into the second layer, and loading the second compacted material onto the top of the TC4 titanium alloy return material;

[0049] This step mainly involves loading the materials into the furnace. The dried first compacted material is loaded into the bottom layer of the material box 3 of the electron beam cooling hearth furnace. The second layer is loaded with the TC4 titanium alloy return material above the bottom layer. The third layer is loaded with the second compacted material above the TC4 titanium alloy return material. The material layer heights of the first compacted material and the second compacted material are 110-140 mm, and the material layer height of the TC4 titanium alloy return material is 300-500 mm.

[0050] S5, after the furnace is loaded, the electron beam cooling furnace is sealed, and after leak detection, vacuum is evacuated until the vacuum degree in the electron beam cooling furnace reaches 1 Pa, and then the gun is preheated;

[0051] S6, start the 1# electron gun 7, 2# electron gun 8, 3# electron gun 9, and 4# electron gun 10 in the cooling bed for heating. When the liquid level in the cooling bed is higher than the overflow port, start the 5# electron gun 11 for heating. When the titanium liquid in the cooling bed flows into the crystallizer 6, start the 6# electron gun 12 and 7# electron gun 13 for heating.

[0052] This step mainly utilizes the electron guns arranged on the cooling bed to heat the material 4; the material 4 is pushed from the material box 3 to the cooling bed 5 by the pushing screws 1 and the pushing plates 2 on both sides, and is heated and melted under the action of the electron guns in the cooling bed 5. Among them, the power of the 1# electron gun, the 2# electron gun, the 3# electron gun, and the 4# electron gun is 100~150kw, the power of the 5# electron gun is 100~130kw, and the heating power of the 6# electron gun and the 7# electron gun is 100~180kW;

[0053] S7, when the titanium liquid fills the crystallizer 6, increase the power of the 6# electron gun 12 and the 7# electron gun 13 until the titanium liquid fills the entire crystallizer 6, and then start melting and ingot pulling;

[0054] This step is the melting and ingot pulling process. When the titanium liquid gradually fills the crystallizer 6, the electron beam air intake is adjusted synchronously, thereby increasing the power of the 6# electron gun 12 and the 7# electron gun 13 to 240 ~ 300 kW. After the titanium liquid fills the entire crystallizer 6, melting and ingot pulling begins. In the above-mentioned melting and casting process, the power of the 1# electron gun 7, 2# electron gun 8, 3# electron gun 9, 4# electron gun 10, 5# electron gun 11, 6# electron gun 12, and 7# electron gun 13 is adjusted to ensure that the melting speed of the material matches the ingot pulling speed. In the specific melting and casting process, the power of the 1# electron gun 7, 2# electron gun 8, 3# electron gun 9, and 4# electron gun 10 is 150~300kW, the power of the 5# electron gun 11 is 100~130kW, and the power of the 6# electron gun 12 and 7# electron gun 13 is 240~300kW; during the melting and casting process, the liquid level in the crystallizer 6 is controlled to be 5~30mm away from the edge of the crystallizer 6; in addition, during the melting and casting process, the vacuum degree of the electron beam cooling hearth furnace is controlled at 0.5~3Pa. During the ingot pulling process, the liquid flow rate flowing into the crystallizer 6 must be kept matched with the ingot pulling speed; in a specific embodiment, the ingot pulling speed is controlled at 300~500mm / h;

[0055] S8, after the melting and casting is completed, the tail of the ingot is subjected to shrinkage feeding, and then cooled. After cooling, the electron beam cooling furnace is opened, and the two-phase titanium alloy ingot is taken out from the crystallizer 6.

[0056] The composition of the two-phase titanium alloy ingot prepared by the above method is as follows in percentage by mass: Al 5.0% to 7.0%, V 3.0% to 5.0%, Cr 0.5% to 2.0%, Fe 0.5% to 1.5%, and the balance is Ti and unavoidable impurities;

[0057] The density of the two-phase titanium alloy ingot is 4.4 ~4.5 g / cm 3 , tensile strength ≥865 MPa, yield strength ≥825 MPa, impact toughness 40~50 J / cm 2 , the elongation is 8~11%.

[0058] The method for preparing high-performance two-phase titanium alloy at low cost by melting flat ingots in an electron beam cooling hearth furnace of the present invention is further described below with reference to specific examples.

[0059] The target composition of the two-phase titanium alloy ingots melted and cast in the following examples is: Al: 6%, V: 4.0%, Cr: 1.0%, Fe: 1.0%, and the balance being Ti and unavoidable impurities.

[0060] Example 1

[0061] This embodiment adopts an electron beam cooling furnace to melt flat ingots to prepare a high-performance two-phase titanium alloy at low cost. The specific process is as follows:

[0062] (1) The addition ratio of TC4 titanium alloy return material is 50%, and sponge titanium, aluminum vanadium alloy, ferrochrome alloy, aluminum bean, and titanium iron alloy are selected for material composition. The proportions are made according to the nominal composition of the two-phase titanium alloy Ti-7.6Al-4V-1.4Cr-1Fe. The amount of each raw material is calculated and weighed.

[0063] (2) Sponge titanium is divided into two parts. One part of sponge titanium accounts for 50-60% of the total amount of sponge titanium, and is mixed with aluminum-vanadium alloy, aluminum bean, and titanium-iron alloy according to the required ratio and pressed into a first pressed block material; the remaining sponge titanium is mixed with ferrochromium alloy according to the required ratio and pressed into a second pressed block material.

[0064] (3) The first pressed material and the second pressed material are sent to a drying furnace for drying: the drying temperature is 150-180°C and the drying time is 2 hours.

[0065] (4) The dried pressed materials are loaded into the furnace, and the first pressed materials are placed on the bottom layer of the material box 3, the TC4 titanium alloy return material is placed on the second layer, and the second pressed materials are placed on the third layer; wherein, the material layer height of the first pressed materials and the second pressed materials is 110~140mm, and the material layer height of the TC4 titanium alloy return material is 300~500mm.

[0066] (5) After the furnace is loaded, the electron beam cooling bed furnace is sealed and leak-checked. After the leak-check is completed, the furnace is evacuated. When the vacuum is evacuated to 1 Pa, the gun is preheated.

[0067] (6) First, open the 1# electron gun 7, 2# electron gun 8, 3# electron gun 9, and 4# electron gun 10 in the cooling bed 5 to heat the material 4. When the liquid level in the cooling bed 5 is higher than the overflow port, open the 5# electron gun 11 to heat it. After the liquid in the cooling bed flows into the crystallizer 6, open the 6# electron gun 12 and 7# electron gun 13 to heat the liquid. Among them, the power of the 1# electron gun, 2# electron gun, 3# electron gun, and 4# electron gun is 100~150kw, the power of the 5# electron gun is 100~130kw, and the heating power of the 6# electron gun and 7# electron gun is 100~180kW.

[0068] (7) When the titanium liquid gradually fills the crystallizer 6, the electron beam air flow rate is adjusted synchronously, thereby increasing the power of the 6# electron gun 12 and the 7# electron gun 13 to 300kW until the liquid fills the entire crystallizer 6. Normal melting and ingot pulling can then begin. During the ingot pulling process, the liquid flow rate into the crystallizer 6 must be kept consistent with the ingot pulling speed.

[0069] (8) During the melting and casting process, the power of the electron gun is adjusted to ensure that the melting speed of the material matches the ingot pulling speed. Among them, the power of the 1# electron gun 7, 2# electron gun 8, 3# electron gun 9, and 4# electron gun 10 is 150~300kW, the power of the 5# electron gun 11 is 100~130kW, and the power of the 6# electron gun 12 and 7# electron gun 13 is 240~300kW. The ingot pulling speed is controlled at 300~500mm / h, the vacuum range in the furnace is 0.5~3Pa, and the liquid level height in the crystallizer 6 is controlled at 5~30mm from the edge of the crystallizer 6.

[0070] (9) After the melting and casting process is completed, the tail of the ingot is subjected to shrinkage feeding. After the shrinkage feeding is completed, the ingot is cooled. After cooling, the electron beam cooling furnace is opened, and finally the two-phase titanium alloy ingot is taken out from the crystallizer 6.

[0071] The properties of the two-phase titanium alloy ingot prepared in this example are as follows: density 4.47 g / cm 3 , tensile strength is 866MPa, yield strength is 828MPa, and impact toughness is 46 J / cm 2 , the elongation is 8.3%.

[0072] Example 2

[0073] This embodiment adopts an electron beam cooling furnace to melt flat ingots to prepare a high-performance two-phase titanium alloy at low cost. The specific process is as follows:

[0074] (1) The addition ratio of TC4 titanium alloy return material is 60%, and sponge titanium, aluminum vanadium alloy, ferrochrome alloy, aluminum bean, and titanium iron alloy are selected for material composition. The proportions are made according to the nominal composition of the two-phase titanium alloy Ti-7.4Al-4V-1.4Cr-1Fe. The amount of each raw material is calculated and weighed.

[0075] (2) Sponge titanium is divided into two parts. One part of sponge titanium accounts for 50-60% of the total amount of sponge titanium, and is mixed with aluminum-vanadium alloy, aluminum bean, and titanium-iron alloy according to the required ratio and pressed into a first pressed block material; the remaining sponge titanium is mixed with ferrochromium alloy according to the required ratio and pressed into a second pressed block material.

[0076] (3) Send the first pressed material and the second pressed material into a drying furnace for drying: the drying temperature is 150~180℃, and the drying time is not less than 2 hours.

[0077] (4) The dried pressed materials are loaded into the furnace, and the first pressed materials are placed on the bottom layer of the material box 3, the TC4 titanium alloy return material is placed on the second layer, and the second pressed materials are placed on the third layer; wherein, the material layer height of the first pressed materials and the second pressed materials is 110-140 mm, and the material layer height of the TC4 titanium alloy return material is 300-500 mm.

[0078] (5) After the furnace is loaded, the electron beam cooling bed furnace is sealed and leak-checked. After the leak-check is completed, the furnace is evacuated. When the vacuum is evacuated to 1 Pa, the gun is preheated.

[0079] (6) First, turn on the 1# electron gun 7, 2# electron gun 8, 3# electron gun 9, and 4# electron gun 10 in the cooling bed 5 to heat the material 4. When the liquid level in the cooling bed is higher than the overflow port, turn on the 5# electron gun for heating. After the liquid in the cooling bed flows into the crystallizer 6, turn on the 6# electron gun and the 7# electron gun to heat the liquid. Among them, the power of the 1# electron gun, the 2# electron gun, the 3# electron gun, and the 4# electron gun is 100~150kw, the power of the 5# electron gun is 100~130kw, and the heating power of the 6# electron gun and the 7# electron gun is 100~180kW.

[0080] (7) When the titanium liquid gradually fills the crystallizer 6, the electron beam air flow rate is adjusted synchronously, thereby increasing the power of the 6# electron gun 12 and the 7# electron gun 13 to 300kW until the liquid fills the entire crystallizer 6. Normal melting and ingot pulling can then begin. During the ingot pulling process, the liquid flow rate into the crystallizer 6 must be kept consistent with the ingot pulling speed.

[0081] (8) During the melting and casting process, the power of the electron gun is adjusted to ensure that the melting speed of the material matches the ingot pulling speed. Among them, the power of the 1# electron gun 7, 2# electron gun 8, 3# electron gun 9, and 4# electron gun 10 is 150~300kW, the power of the 5# electron gun 11 is 100~130kW, and the power of the 6# electron gun 12 and 7# electron gun 13 is 240~300kW. The ingot pulling speed is controlled at 300~500mm / h, the vacuum range in the furnace is 0.5~3Pa, and the liquid level height in the crystallizer 6 is controlled at 5~30mm from the edge of the crystallizer 6.

[0082] (9) After the melting and casting process is completed, the tail of the ingot is subjected to shrinkage feeding. After the shrinkage feeding is completed, the ingot is cooled. After cooling, the electron beam cooling furnace is opened, and finally the two-phase titanium alloy ingot is taken out from the crystallizer 6.

[0083] The properties of the two-phase titanium alloy ingot prepared in this example are as follows: density 4.49 g / cm 3 , tensile strength is 873MPa, yield strength is 835MPa, and impact toughness is 47J / cm 2 , the elongation is 9.4%.

[0084] Example 3

[0085] This embodiment adopts an electron beam cooling furnace to melt flat ingots to prepare a high-performance two-phase titanium alloy at low cost. The specific process is as follows:

[0086] (1) The addition ratio of TC4 titanium alloy return material is 70%, and sponge titanium, aluminum vanadium alloy, ferrochrome alloy, aluminum bean, and titanium iron alloy are selected for material composition. The proportions are made according to the nominal composition of the two-phase titanium alloy Ti-7.2Al-4V-1.4Cr-1Fe, and the amount of each raw material is calculated and weighed.

[0087] (2) Sponge titanium is divided into two parts. One part of sponge titanium accounts for 50-60% of the total amount of sponge titanium, and is mixed with aluminum-vanadium alloy, aluminum bean, and titanium-iron alloy according to the required ratio and pressed into a first pressed block material; the remaining sponge titanium is mixed with ferrochromium alloy according to the required ratio and pressed into a second pressed block material.

[0088] (3) The first pressed material and the second pressed material are sent to a drying furnace for drying: the drying temperature is 150-180°C and the drying time is 2 hours.

[0089] (4) The dried pressed materials are loaded into the furnace, and the first pressed materials are placed on the bottom layer of the material box 3, the TC4 titanium alloy return material is placed on the second layer, and the first pressed materials are placed on the third layer; wherein, the material layer height of the first pressed materials and the second pressed materials is 110~140mm, and the material layer height of the TC4 titanium alloy return material is 300~500mm.

[0090] (5) After the furnace is loaded, the electron beam cooling bed furnace is sealed and leak-checked. After the leak-check is completed, the furnace is evacuated. When the vacuum is evacuated to 1 Pa, the gun is preheated.

[0091] (6) First, open the 1# electron gun 7, 2# electron gun 8, 3# electron gun 9, and 4# electron gun 10 in the cooling bed 5 to heat the material 4. When the liquid level in the cooling bed is higher than the overflow port, open the 5# electron gun 11 for heating. After the liquid in the cooling bed flows into the crystallizer 6, open the 6# electron gun 12 and 7# electron gun 13 to heat the liquid. Among them, the power of the 1# electron gun, 2# electron gun, 3# electron gun, and 4# electron gun is 100~150kw, the power of the 5# electron gun is 100~130kw, and the heating power of the 6# electron gun and 7# electron gun is 100~180kW.

[0092] (7) When the titanium liquid gradually fills the crystallizer 6, the electron beam air flow rate is adjusted synchronously, thereby increasing the power of the 6# electron gun 12 and the 7# electron gun 13 by 300kW until the liquid fills the entire crystallizer 6. Normal melting and ingot pulling can then begin. During the ingot pulling process, the liquid flow rate into the crystallizer 6 must be kept consistent with the ingot pulling speed.

[0093] (8) During the melting and casting process, the power of the electron gun is adjusted to ensure that the melting speed of the material matches the ingot pulling speed. Among them, the power of the 1# electron gun 7, 2# electron gun 8, 3# electron gun 9, and 4# electron gun 10 is 150~300kW, the power of the 5# electron gun 11 is 100~130kW, and the power of the 6# electron gun 12 and 7# electron gun 13 is 240~300kW. The ingot pulling speed is controlled at 300~500mm / h, the vacuum range in the furnace is 0.5~3Pa, and the liquid level height in the crystallizer 6 is controlled at 5~30mm from the edge of the crystallizer 6.

[0094] (9) After the melting and casting process is completed, the tail of the ingot is subjected to shrinkage feeding. After the shrinkage feeding is completed, the ingot is cooled. After cooling, the electron beam cooling furnace is opened, and finally the two-phase titanium alloy ingot is taken out from the crystallizer 6.

[0095] The properties of the two-phase titanium alloy ingot prepared in this example are as follows: density 4.46 g / cm 3 , tensile strength is 869 MPa, yield strength is 832 MPa, and impact toughness is 45 J / cm 2 , the elongation is 8.5%.

[0096] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, and all of these should be included in the scope of the claims of the present invention.

Claims

1. A method for preparing high-performance two-phase titanium alloy at low cost by melting flat ingots in an electron beam cooling furnace, characterized in that: The following steps are involved: S1, according to the nominal composition of the two-phase titanium alloy, calculate the amount of TC4 titanium alloy return material, sponge titanium, aluminum vanadium alloy, ferrochrome alloy, aluminum beans, and titanium ferroalloy and weigh them, and control the addition amount of TC4 titanium alloy return material to be ≥50%; S2, dividing the titanium sponge into two parts, mixing one part of the titanium sponge with aluminum-vanadium alloy, aluminum bean, and titanium-iron alloy and briquetting to obtain a first briquette material, and mixing the other part of the titanium sponge with chromium-iron alloy and briquetting to obtain a second briquette material; S3, drying the first briquetting material and the second briquetting material; S4, loading the dried first compacted material into the bottom layer of the material box of the electron beam cooling hearth furnace, loading the TC4 titanium alloy return material into the second layer, and loading the second compacted material onto the top of the TC4 titanium alloy return material; S5, after the furnace is loaded, the electron beam cooling furnace is sealed, and after leak detection, vacuum is evacuated until the vacuum degree in the electron beam cooling furnace reaches 1 Pa, and then the gun is preheated; S6, open the 1# electron gun, 2# electron gun, 3# electron gun, and 4# electron gun in the cooling bed for heating. When the liquid level in the cooling bed is higher than the overflow port, open the 5# electron gun for heating. When the titanium liquid in the cooling bed flows into the crystallizer, open the 6# electron gun and 7# electron gun for heating; S7, when the titanium liquid fills the crystallizer, increase the power of the 6# electron gun and the 7# electron gun until the titanium liquid fills the entire crystallizer, then start melting and pulling the ingot; S8, after the melting and casting is completed, the tail of the ingot is fed for shrinkage, and then cooled. After cooling, the electron beam cooling furnace is opened, and the two-phase titanium alloy ingot is taken out from the crystallizer; In the step S1: the nominal composition of the two-phase titanium alloy is Ti-(6.90-7.60)Al-(3.90-4.10)V-(1.30-1.65)Cr-(0.90-1.10)Fe; In step S2, the titanium sponge used in the first compacted material accounts for 50-60% of the total amount of the titanium sponge; In step S4, the material layer heights of the first and second compressed materials are 110-140 mm, and the material layer height of the TC4 titanium alloy return material is 300-500 mm; In step S7, the power of the 6# electron gun and the 7# electron gun is increased to 240-300 kW; During the melting and casting process, the power of the 1# electron gun, 2# electron gun, 3# electron gun, 4# electron gun, 5# electron gun, 6# electron gun, and 7# electron gun is adjusted to ensure that the melting speed of the material matches the ingot pulling speed; During the ingot pulling process, the flow rate of the titanium liquid into the crystallizer is kept matching the ingot pulling speed.

2. The method for preparing high-performance two-phase titanium alloy at low cost by electron beam cooling furnace melting slab process according to claim 1, characterized in that: In the step S1, the amount of the TC4 titanium alloy return material added is 50% to 80%.

3. The method for preparing high-performance two-phase titanium alloy at low cost by electron beam cooling furnace slab melting process as claimed in claim 1, characterized in that: In the step S3, during the drying process, the drying temperature is 150-180° C. and the drying time is 2-4 hours.

4. The method for preparing high-performance two-phase titanium alloy at low cost by electron beam cooling furnace slab melting process as claimed in claim 1, characterized in that: In step S6, the power of the 1# electron gun, the 2# electron gun, the 3# electron gun, and the 4# electron gun is 100-150 kW, the power of the 5# electron gun is 100-130 kW, and the heating power of the 6# electron gun and the 7# electron gun is 100-180 kW.

5. The method for preparing high-performance two-phase titanium alloy at low cost by electron beam cooling furnace slab melting process as claimed in claim 1, characterized in that: In step S7: During the melting and casting process, the vacuum degree of the electron beam cooling hearth furnace is controlled at 0.5-3 Pa; During the casting process, the liquid level in the crystallizer is controlled to be 5 to 30 mm from the edge of the crystallizer; The ingot pulling speed is controlled at 300-500 mm / h.

6. The method for preparing high-performance two-phase titanium alloy at low cost by electron beam cooling furnace melting slab process as claimed in claim 5, characterized in that: In step S7, during the melting and casting process, the power of the 1# electron gun, the 2# electron gun, the 3# electron gun, and the 4# electron gun is 150-300 kW, the power of the 5# electron gun is 110-130 kW, and the power of the 6# electron gun and the 7# electron gun is 240-300 kW.

7. The method for preparing high-performance two-phase titanium alloy at low cost by electron beam cooling furnace slab melting process according to any one of claims 1 to 6, characterized in that: The composition of the two-phase titanium alloy ingot is as follows by mass percentage: Al 5.0% to 7.0%, V 3.0% to 5.0%, Cr 0.5% to 2.0%, Fe 0.5% to 1.5%, and the balance is Ti and unavoidable impurities; The density of the two-phase titanium alloy ingot is 4.4-4.5 g / cm 3 , tensile strength ≥865MPa, yield strength ≥825MPa, impact toughness 40~50J / cm 2 , the elongation is 8~11%.

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