Titanium alloy large-size bar with temperature of 600-650 DEG C for aviation and preparation method of titanium alloy large-size bar

Abstract

The invention provides a 600-650 DEG C titanium alloy large-size bar for aviation and a preparation method thereof, and belongs to the technical field of alloys. Comprising the steps that a titanium alloy cast ingot is heated and homogenized, and then a fast forging machine or a hydraulic press is used for cogging and forging in a beta-phase region; heating and repeatedly upsetting and drawing out; the forged blank is heated, upset and drawn out repeatedly; heating the blank and repeatedly upsetting and drawing out the blank; finally, the forged blank is heated, subjected to repeated upsetting and drawn to the required size; and the equiaxial or double-state structure large-specification bar of which the macrostructure is fuzzy crystal and the microstructure is uniform is obtained, the ultrasonic flaw detection clutter level of the bar is low, and the flaw detection level is relatively high. The prepared titanium alloy large-size bar used for aviation at the temperature of 600-650 DEG C is good in obdurability matching, good in durability and creep strength and thermal stability matching, convenient to operate and high in process controllability, and the prepared titanium alloy large-size bar used for aviation at the temperature of 600-650 DEG C is good in batch stability.

Description

Technical Field

[0001] The present invention relates to the technical field of alloys, and in particular to a large-size 600-650°C titanium alloy bar for aviation and a preparation method thereof. Background Art

[0002] Large-sized high-temperature titanium alloy bars are primarily used in forgings and serve as blanks. The quality, performance, stability, and consistency of large-sized high-temperature titanium alloy bars are primarily related to the bar's macrostructure, microstructure uniformity, and texture. The microstructure and texture of large-sized bars are primarily determined by their manufacturing process.

[0003] The invention patents "A method for preparing titanium alloy bars (CN102230097A)", "A method for forging large-size high-temperature resistant titanium alloy bars for engines (CN106734796B)", "A method for preparing high-temperature titanium alloy bars (CN109234554B)" and "A method for preparing high-temperature, high thermal stability and high creep resistance titanium alloy bars (CN109371268B)" etc., all use cooling forging starting from the β single-phase region. The ingot is first forged at a higher temperature in the β phase region, gradually transitioning to a lower temperature forging in the β phase region, and finally lowering the temperature to enter the α+β two-phase region for multi-fire forging to obtain large-size titanium alloy bars.

[0004] The invention patents "Ti-6Al-4V titanium alloy large-size bar processing method (CN101476096A)" and "TC19 titanium alloy large-size bar forging method (CN107350406A)" have the following main features: the forging temperature is gradually reduced from the β single-phase region to the α+β two-phase region. During the multi-fire forging process, homogenization annealing of the β single-phase region is added, but the final forging is finally completed in the α+β two-phase region to obtain large-size titanium alloy bars.

[0005] The aforementioned authorized invention patents for large-scale bar production are all aimed at producing large-scale titanium alloy bars with a good balance of strength and toughness. However, as the diameter or weight of the bar increases, the strain and temperature fields at different locations in the bar increase during hot working deformation, making it difficult to ensure the uniformity of the bar's structure and the stability of its performance. This significantly increases the difficulty of producing high-quality large-scale titanium alloy bars. Summary of the Invention

[0006] The present invention aims to provide a large-scale 600°C-650°C titanium alloy bar for aviation applications and a method for preparing the same. The method is easy to operate and highly controllable. The large-scale 600°C-650°C titanium alloy bar for aviation applications obtained using the present invention exhibits uniform microstructure, stable mechanical properties, and well-matched thermal stability and thermal strength, meeting the performance requirements of forgings with different microstructures.

[0007] The technical solution of the present invention is achieved as follows:

[0008] The present invention provides a large-size titanium alloy bar with a temperature of 600° C. to 650° C. for aviation and a preparation method thereof, comprising the following steps:

[0009] (1) The raw material is 0-1 grade sponge titanium, and Sn, Mo, Si, and Nb are added in the form of an intermediate alloy; the alloy elements or the intermediate alloy are packaged into an alloy package, and then electrode pressing, electrode welding, and three vacuum consumable arc furnace smelting are carried out in sequence to obtain a titanium alloy ingot; or the sponge titanium, the alloy elements, and the intermediate alloy are uniformly mixed in a mixer, and then electrode pressing, electrode welding, and three vacuum consumable arc furnace smelting are carried out in sequence to obtain a titanium alloy ingot.

[0010] (2) using a resistance furnace or a gas furnace with an oxidizing atmosphere to heat the titanium alloy ingot in step (1) to 1150° C. to 1200° C. for homogenization treatment, and then repeatedly upsetting and stretching the ingot using a fast forging machine or a hydraulic press;

[0011] (3) using a resistance furnace or a gas furnace with an oxidizing atmosphere to heat and forge the titanium alloy forging blank described in step (2);

[0012] (4) using a resistance furnace to heat the titanium alloy forging blank described in step (3), and repeatedly performing upsetting and stretching forging;

[0013] (5) using a resistance furnace or a gas furnace with an oxidizing atmosphere to heat and forge the titanium alloy forging blank described in step (4);

[0014] (6) using a resistance furnace to heat the titanium alloy forging blank described in step (5), and repeatedly performing upsetting and stretching forging;

[0015] (7) using a resistance furnace to heat and stretch the titanium alloy forging blank described in step (6);

[0016] (8) The rods described in step (7) are subjected to solution aging treatment to obtain large-sized titanium alloy rods for aviation use at 600°C-650°C.

[0017] As a further improvement of the present invention, in step (1), Al is added as an intermediate alloy, and the insufficient part is added as pure Al; Zr and C are added in the form of sponge Zr and carbon powder respectively; the titanium alloy ingot is a 600℃-650℃ titanium alloy ingot with a size of Φ380mm~Φ720mm.

[0018] As a further improvement of the present invention, the upsetting and drawing forging in step (2) is performed 1 to 3 times, the forging ratio of the forging blank in each fire is not less than 2, and the final forging temperature is not lower than 950°C.

[0019] As a further improvement of the present invention, the heating to 1050°C to 1100°C in step (3) is performed by forging 2 to 3 times using a fast forging machine or a hydraulic press, the forging ratio of the forging blank in each fire is not less than 2.6, the total forging ratio is not less than 6, and the final forging temperature is not lower than 900°C.

[0020] As a further improvement of the present invention, the heating to T β -120℃~T β -30℃, where T β The temperature is the transformation temperature of the α+β / β phase, the forging is performed 2 to 3 times, the forging ratio of the forging blank in each fire is not less than 2.6, the total forging ratio is not less than 8, and the final forging temperature is not less than 850°C.

[0021] As a further improvement of the present invention, the heating to T β +30℃~T β +60℃, where T β The temperature is the transformation temperature of the α+β / β phase, the forging is performed in 1 to 2 fires, the forging ratio of the forging blank in each fire is not less than 2.6, and the final forging temperature is not less than 900°C.

[0022] As a further improvement of the present invention, the heating to T β -120℃~T β -30℃, where T β The temperature is the transformation temperature of α+β / β phase, the number of upsetting and drawing forging is 3 to 4 times, the forging ratio of the forging billet in each fire is not less than 2.6, the total forging ratio is not less than 10, and the final forging temperature is not less than 850℃.

[0023] As a further improvement of the present invention, the heating to T β -120℃~T β -30℃, where T β The temperature is the transition temperature of the α+β / β phase, the steel is drawn to the required size, the total forging ratio is not less than 3, and the final forging temperature is not less than 850°C.

[0024] As a further improvement of the present invention, the solution aging treatment system of the bar in step (8) is: the solution treatment system is Tβ -60℃~T β The rods are kept at -20°C for 2h to 4h and then oil-cooled or water-quenched. The aging treatment system is kept at 680°C to 720°C for 2h to 8h and then air-cooled. The size of the rods is Φ200mm to Φ500mm.

[0025] Preferably, during the solution aging treatment, a grain refiner is added in an amount of 1 to 2 wt% of the total mass of the system, and the preparation method of the grain refiner is as follows:

[0026] S1. Aluminum chips, titanium chips, lanthanum oxide and cerium oxide powders were heated and mixed, and cooled to room temperature to obtain a mixture;

[0027] S2. The mixture was introduced into hydrogen under inert gas, heated for reduction, and then n-hexane was introduced, heated for reaction, and cooled to room temperature to obtain a carbon-containing mixture;

[0028] S3. Heat and melt pure aluminum, add the carbon-containing mixture, sprinkle in potassium chloride, and stir to react. After the reaction is completed, add C2Cl6 to refine and degas, skim off the slag, stir, and pour to obtain a grain refiner.

[0029] Preferably, the mass ratio of aluminum chips, titanium chips, lanthanum oxide and cerium oxide is 1-3:5-10:0.1-0.2:0.1-0.3, the heating temperature is 750-800° C., and the heating time is 30-40 minutes.

[0030] Preferably, the hydrogen ventilation rate is 80-120 mL / min, the temperature is 800-1200° C., and the time is 30-40 min; the n-hexane ventilation rate is 0.5-1 mL / min, the heating reaction temperature is 600-700° C., and the time is 20-30 min.

[0031] Preferably, the mass ratio of the pure aluminum, the carbon-containing mixture, potassium chloride, and C2Cl6 is 30-50:20-30:0.1-0.15:0.1-0.2, the heating temperature is 750-800°C, and the stirring reaction time is 30-50 minutes.

[0032] Solution treatment is a metal heat treatment process, mainly used to improve the performance of the alloy. In the solution treatment, the alloy is heated to a high enough temperature to dissolve the solid into the liquid, and kept at this temperature for a period of time to ensure that the solute (usually alloy elements in solid solution) in the alloy is fully dissolved in the matrix. The purpose of this process is usually to adjust the crystal structure of the alloy, eliminate the inhomogeneity in the solid solution, improve the hardness, strength, corrosion resistance and other properties of the alloy, and by adding grain refiner, after alloy reaction and cooling, the newly formed crystal structure may be more delicate, uniform than the original, so that the alloy has superior performance, such as better strength and toughness.

[0033] The grain refiner prepared by the present application contains Al, Ti, C, and rare earth elements Ce and La, which can form borides, carbides or compounds with other elements in the alloy. These compound particles can act as crystal nuclei to promote grain refinement and improve the strength and hardness of titanium alloy while maintaining or improving its plasticity and toughness. This is because the refined grains increase the total area of grain boundaries, thereby increasing the dislocation obstacles and improving the resistance of metal plastic deformation. At the same time, the refined grains help to reduce shrinkage, reduce the size of the second phase and improve casting defects, and also help to improve the corrosion resistance and machinability of the alloy. The present application uses a melting and mixing method to prepare a mixture, then reduces the oxygen content by hydrogen reduction, and deposits carbon by gas phase deposition, so that carbon can be uniformly distributed on the surface of the mixture, thereby preparing a carbon-containing mixture with appropriate proportion and content. When added to the aluminum liquid, the grain refiner prepared in the solution and aging process promotes the complete transformation of the alpha phase to the beta phase, and after heating is completed, reduces the transformation of the beta phase to the alpha phase, or forms the beta phase into fine alpha' phase, so that the rod prepared by the present application not only has uniform organization, stable mechanical properties, good thermal stability and thermal strength matching, but also has low ultrasonic flaw detection noise level and good flaw detection level.

[0034] The present application further protects a large-size rod of 600-650℃ titanium alloy for aviation prepared by the above preparation method.

[0035] The present application has the following beneficial effects:

[0036] 1) The preparation method of the present application is easy to operate and has strong controllability;

[0037] 2) The beta phase zone forging of the present application can break the coarse as-cast structure of the ingot, avoiding the technical risks brought by the poor uniformity and obvious cracking tendency of low temperature deformation;

[0038] 3) The beta phase zone multi-pass forging of the present application is based on the characteristics of 600-650℃ titanium alloy being easy to crack, which maximizes the prevention of uneven deformation and forging cracking of the alloy, and achieves the purpose of refining the original beta grains;

[0039] 4) After the 600°C-650°C titanium alloy of the present invention is deformed in the α+β two-phase region, the forging temperature is increased to the β phase region for forging, which can further break up the original β grains and refine the rod structure;

[0040] 5) The 600°C-650°C titanium alloy of the present invention needs to be fully deformed in the α+β two-phase region in order to obtain a uniform microstructure while reducing the texture strength of the α phase of the rod;

[0041] 6) The large-scale 600°C-650°C titanium alloy bars for aviation, produced using the method of the present invention, have a fuzzy microstructure at low magnification and an equiaxed or bimodal microstructure at high magnification. These bars exhibit high room-temperature and high-temperature strength, good thermal stability, excellent creep performance, and high ultrasonic flaw detection capabilities. The bars exhibit room-temperature tensile strength greater than 1030 MPa and elongation greater than 8%, 600°C tensile strength greater than 630 MPa and elongation greater than 15%, creep residual deformation at 600°C / 150 MPa / 100h less than 0.14%, and room-temperature tensile elongation greater than 3% and reduction of area greater than 6% after heat exposure at 600°C / 100h. The comprehensive performance of these large-scale 600°C-650°C titanium alloy bars for aviation meets or exceeds the internationally advanced level for similar alloys. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 The macrostructure of the large-sized titanium alloy bar for aviation use at 600°C-650°C prepared in Example 4 of the present invention is a fuzzy crystal result diagram.

[0044] Figure 2 This is the isometric structure diagram of the large-size 600°C-650°C titanium alloy bar for aviation use prepared in Example 4 of the present invention. DETAILED DESCRIPTION

[0045] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0046] Preparation Example 1 Preparation of grain refiner

[0047] The following steps are involved:

[0048] S1. 1 g of aluminum chips, 5 g of titanium chips, 0.1 g of lanthanum oxide, and 0.1 g of cerium oxide powder were heated to 750 ° C, stirred for 30 min, and cooled to room temperature to obtain a mixture;

[0049] S2. The mixture was introduced into hydrogen at a flow rate of 80 mL / min under inert gas protection, heated to 800°C, and reduced for 30 min. Then, n-hexane was introduced at a flow rate of 0.5 mL / min, heated to 600°C, reacted for 20 min, and cooled to room temperature to obtain a carbon-containing mixture;

[0050] S3. Heat 30g of pure aluminum to 750°C, melt it, add 20g of the carbon-containing mixture, sprinkle in 0.1g of potassium chloride, and stir to react for 30 minutes. After the reaction is completed, add 0.1g of C2Cl6 for refining and degassing, skim off the slag, stir, and pour to obtain a grain refiner.

[0051] Preparation Example 2 Preparation of grain refiner

[0052] The following steps are involved:

[0053] S1. 3 g of aluminum chips, 10 g of titanium chips, 0.2 g of lanthanum oxide, and 0.3 g of cerium oxide powder were heated to 800 ° C, stirred and mixed for 40 min, and cooled to room temperature to obtain a mixture;

[0054] S2. The mixture was introduced into hydrogen at a flow rate of 120 mL / min under inert gas protection, heated to 1200°C, and reduced for 40 min. Then, n-hexane was introduced at a flow rate of 1 mL / min, heated to 700°C, reacted for 30 min, and cooled to room temperature to obtain a carbon-containing mixture;

[0055] S3. Heat 50g of pure aluminum to 800℃, melt it, add 30g of carbon-containing mixture, sprinkle in 0.15g of potassium chloride, and stir to react for 50 minutes. After the reaction is completed, add 0.2g of C2Cl6 for refining and degassing, skim off the slag, stir, and pour to obtain a grain refiner.

[0056] Preparation Example 3 Preparation of grain refiner

[0057] The following steps are involved:

[0058] S1. 2 g of aluminum chips, 7 g of titanium chips, 0.15 g of lanthanum oxide, and 0.2 g of cerium oxide powder were heated to 770 ° C, stirred for 35 min, and cooled to room temperature to obtain a mixture;

[0059] S2. The mixture was introduced into hydrogen at a flow rate of 100 mL / min under inert gas protection, heated to 1000°C, and reduced for 35 min. Then, n-hexane was introduced at a flow rate of 0.7 mL / min, heated to 650°C, reacted for 25 min, and cooled to room temperature to obtain a carbon-containing mixture;

[0060] S3. Heat 40g of pure aluminum to 770°C, melt it, add 25g of the carbon-containing mixture, sprinkle in 0.12g of potassium chloride, and stir to react for 40 minutes. After the reaction is completed, add 0.15g of C2Cl6 for refining and degassing, skim off the slag, stir, and pour to obtain a grain refiner.

[0061] Comparative Preparation Example 1

[0062] Compared with Preparation Example 3, the difference is that step S2 is not performed.

[0063] The following steps are involved:

[0064] S1. 2 g of aluminum chips, 7 g of titanium chips, 0.15 g of lanthanum oxide, and 0.2 g of cerium oxide powder were heated to 770 ° C, stirred for 35 min, and cooled to room temperature to obtain a mixture;

[0065] S2. Heat 40g of pure aluminum to 770°C, melt it, add 25g of the mixture, sprinkle in 0.12g of potassium chloride, and stir to react for 40 minutes. After the reaction is completed, add 0.15g of C2Cl6 for refining and degassing, skim off the slag, stir, and pour to obtain a grain refiner.

[0066] Comparative Preparation Example 2

[0067] Compared with Preparation Example 3, the difference is that cerium oxide is not added in step S1.

[0068] The following steps are involved:

[0069] S1. 2 g of aluminum chips, 7 g of titanium chips and 0.35 g of lanthanum oxide powder were heated to 770 ° C, stirred and mixed for 35 min, and cooled to room temperature to obtain a mixture;

[0070] S2. The mixture was introduced into hydrogen at a flow rate of 100 mL / min under inert gas protection, heated to 1000°C, and reduced for 35 min. Then, n-hexane was introduced at a flow rate of 0.7 mL / min, heated to 650°C, reacted for 25 min, and cooled to room temperature to obtain a carbon-containing mixture;

[0071] S3. Heat 40g of pure aluminum to 770°C, melt it, add 25g of the carbon-containing mixture, sprinkle in 0.12g of potassium chloride, and stir to react for 40 minutes. After the reaction is completed, add 0.15g of C2Cl6 for refining and degassing, skim off the slag, stir, and pour to obtain a grain refiner.

[0072] Comparative Preparation Example 3

[0073] The difference compared with Preparation Example 3 is that no lanthanum oxide is added in step S1.

[0074] The following steps are included:

[0075] S1. 2 g of aluminum chips, 7 g of titanium chips and 35 g of cerium oxide powder are heated to 770°C, mixed by stirring for 35 min, and cooled to room temperature to obtain a mixture;

[0076] S2. The mixture is heated to 1000°C under inert gas protection, reduced for 35 min by passing in hydrogen at a flow rate of 100 mL / min, then passed in n-hexane at a flow rate of 0.7 mL / min, heated to 650°C, reacted for 25 min, and cooled to room temperature to obtain a carbon-containing mixture;

[0077] S3. 40 g of pure aluminum is heated to 770°C, melted, 25 g of the carbon-containing mixture is added, 0.12 g of potassium chloride is scattered, stirred for 40 min, after the reaction is completed, 0.15 g of C2Cl6 is added for refining and degassing, the slag is stirred and poured to obtain a grain refiner.

[0078] Comparative Preparation Example 4

[0079] The difference compared with Preparation Example 3 is that no lanthanum oxide and cerium oxide are added in step S1.

[0080] Preparation Example 1

[0081] The following steps are included:

[0082] S1. 2 g of aluminum chips, 7 g of titanium chips and 35 g of cerium oxide powder are heated to 770°C, mixed by stirring for 35 min, and cooled to room temperature to obtain a mixture;

[0083] S2. The mixture is heated to 1000°C under inert gas protection, reduced for 35 min by passing in hydrogen at a flow rate of 100 mL / min, then passed in n-hexane at a flow rate of 0.7 mL / min, heated to 650°C, reacted for 25 min, and cooled to room temperature to obtain a carbon-containing mixture;

[0084] S3. 40 g of pure aluminum is heated to 770°C, melted, 25 g of the carbon-containing mixture is added, 0.12 g of potassium chloride is scattered, stirred for 40 min, after the reaction is completed, 0.15 g of C2Cl6 is added for refining and degassing, the slag is stirred and poured to obtain a grain refiner.

[0085] 1) Ingot smelting: Al-Mo, Ti-Sn, Al-Si and Al-Nb intermediate alloy and sponge Zr, pure Al and carbon powder are made into an alloy package, then pressed into an electrode with 0-grade titanium sponge, and then subjected to vacuum plasma welding and three times of vacuum consumable arc furnace smelting to obtain a 600℃-650℃ titanium alloy ingot with a diameter of 710 mm; the weight percentage of each component of the 600℃-650℃ titanium alloy ingot is Al: 5.8%, Sn: 3.8%, Zr: 3.5%, Mo: 0.5%, Si: 0.39%, Nb: 0.7%, C: 0.06%;

[0086] 2) The 600℃-650℃ titanium alloy ingot of step 1) is heated to 1200℃ for homogenization treatment by using an electric resistance furnace, and then repeatedly upset and elongated by a hydraulic press for 2 heating times, the forging ratio of the forging blank per heating time is not less than 2, and the final forging temperature is not less than 950℃;

[0087] 3) The forging blank of step 2) is heated to 1100℃ by using an electric resistance furnace, and then repeatedly upset and elongated by a hydraulic press for 3 heating times, the forging ratio of the forging blank per heating time is not less than 2.6, the total forging ratio is not less than 6, and the final forging temperature is not less than 900℃;

[0088] 4) The forging blank of step 3) is heated to T β -30℃ by using an electric resistance furnace, and then repeatedly upset and elongated by a hydraulic press for 3 heating times, the forging ratio of the forging blank per heating time is not less than 2.6, the total forging ratio is not less than 8, and the final forging temperature is not less than 850℃;

[0089] 5) The forging blank of step 4) is heated to T β +30℃ by using an electric resistance furnace, and then repeatedly upset and elongated by a hydraulic press for 2 heating times, the forging ratio of the forging blank per heating time is not less than 2.6, and the final forging temperature is not less than 900℃;

[0090] 6) The forging blank of step 5) is heated to T β -80℃ by using an electric resistance furnace, and then repeatedly upset and elongated by a hydraulic press for 3 heating times, the total forging ratio is not less than 10, and the final forging temperature is not less than 850℃;

[0091] 7) The forging blank of step 6) is heated to T β -30℃ by using an electric resistance furnace, and then elongated to a Φ500 mm bar by a hydraulic press, the total forging ratio is not less than 3, and the final forging temperature is not less than 850℃;

[0092] 8) The large-size bar of the 600℃-650℃ titanium alloy for aviation of step 7) is subjected to solid solution and aging treatment by using an electric resistance furnace, and 1wt% of the grain refiner prepared in preparation example 1 is added, the solid solution treatment system is T β -30℃ for 2h and then oil cooling, and the aging treatment system is 680℃ for 4h and then air cooling.

[0093] Example 2

[0094] 1) Ingot Melting: The ingot preparation method is the same as that in Example 1, except that the diameter of the 600°C-650°C titanium alloy ingot is 620 mm;

[0095] 2) using a resistance furnace, heating the titanium alloy ingot at a temperature of 600° C. to 650° C. in step 1) to 1150° C. for homogenization treatment, and then repeatedly upsetting and stretching forging the ingot using a hydraulic press for one cycle, with a forging ratio of not less than 2 and a final forging temperature of not less than 950° C.;

[0096] 3) using a resistance furnace, heating the forging blank described in step 2) to 1050° C., and then repeatedly upsetting and stretching forging the blank three times using a hydraulic press, wherein the forging ratio of each forging time is not less than 2.6, the total forging ratio is not less than 6, and the final forging temperature is not less than 900° C.; after the forging blank is forged in the last forging time, it is cooled by water cooling.

[0097] 4) Using a resistance furnace, heat the forging blank in step 3) to T β -60℃, then use hydraulic press to repeatedly upsetting and drawing forging for 3 times, the forging ratio of each forging is not less than 2.6, the total forging ratio is not less than 8, and the final forging temperature is not less than 850℃;

[0098] 5) Using a resistance furnace, heat the forging blank in step 4) to T β +30℃, then use a hydraulic press to repeatedly upsetting and stretching for 2 times, the forging ratio of the forging blank in each fire is not less than 2.6, and the final forging temperature is not less than 900℃;

[0099] 6) Using a resistance furnace, heat the forging blank in step 5) to T β -30℃, then use a hydraulic press to repeatedly upsetting and stretching forging for 3 times, the total forging ratio is not less than 10, and the final forging temperature is not less than 850℃;

[0100] 7) Using a resistance furnace, heat the forging blank in step 6) to T β -40℃, then use hydraulic press to stretch to Φ400mm bar, the total forging ratio is not less than 3, and the final forging temperature is not less than 850℃;

[0101] 8) Using a resistance furnace, the large-size titanium alloy bar for aviation use at 600°C-650°C in step 7) was subjected to solution aging treatment, and 1 wt% of the grain refiner prepared in Preparation Example 2 was added to the total weight of the system. The solution treatment system was T β Keep at -60℃ for 3 hours and then cool with oil. The aging treatment system is to keep at 680℃ for 5 hours and then cool with air.

[0102] Example 3

[0103] 1) Ingot Melting: The ingot preparation method is the same as that in Example 1, except that the diameter of the 600°C-650°C titanium alloy ingot is 380 mm;

[0104] 2) using a resistance furnace, heating the titanium alloy ingot at a temperature of 600° C. to 650° C. in step 1) to 1150° C. for homogenization treatment, and then repeatedly upsetting and drawing forging the ingot three times using a hydraulic press, with the forging ratio of each forging being not less than 2, and the final forging temperature being not less than 950° C.;

[0105] 3) using a resistance furnace, heating the forging blank described in step 2) to 1070° C., and then repeatedly upsetting and stretching forging the blank twice using a hydraulic press, wherein the forging ratio of each forging blank is not less than 2.6, the total forging ratio is not less than 6, and the final forging temperature is not less than 900° C.;

[0106] 4) Using a resistance furnace, heat the forging blank in step 3) to T β -30℃, then use a hydraulic press to repeatedly upsetting and stretching for 3 times, the forging ratio of the forging billet each time is not less than 2.6, the total forging ratio is not less than 8, and the final forging temperature is not less than 850℃;

[0107] 5) Using a resistance furnace, heat the forging blank in step 4) to T β +60℃, then use a hydraulic press to repeatedly upsetting and stretching forging for 1 time, the forging ratio is not less than 2.6, and the final forging temperature is not less than 900℃;

[0108] 6) Using a resistance furnace, heat the forging blank in step 5) to T β -50℃, then use a hydraulic press to repeatedly upsetting and stretching forging for 4 times, the total forging ratio is not less than 10, and the final forging temperature is not less than 850℃;

[0109] 7) Using a resistance furnace, heat the forging blank in step 6) to T β -50℃, then use a hydraulic press to stretch to Φ200mm bar, the total forging ratio is not less than 3, and the final forging temperature is not less than 850℃;

[0110] 8) Using a resistance furnace, the large-size titanium alloy bar for aviation use at 600°C-650°C in step 7) was subjected to solution aging treatment, and 1 wt% of the grain refiner prepared in Preparation Example 3 was added to the total weight of the system. The solution treatment system was T β Keep at -20℃ for 2h and then cool with oil. The aging treatment system is to keep at 720℃ for 8h and then cool with air.

[0111] Example 4

[0112] 1) Ingot Melting: Al-Mo, Ti-Sn, Al-Si and Al-Nb master alloys, sponge Zr, pure Al and carbon powder are mixed evenly with grade 0 sponge titanium in a mixer, and then pressed into electrodes. The electrodes are then subjected to vacuum plasma welding and three vacuum consumable arc furnace melting to obtain a 600°C-650°C titanium alloy ingot with a diameter of 720 mm. The weight percentages of the components of the 600°C-650°C titanium alloy ingot are Al: 5.8%, Sn: 3.8%, Zr: 3.5%, Mo: 0.5%, Si: 0.39%, Nb: 0.7%, and C: 0.06%.

[0113] 2) using a resistance furnace, heating the titanium alloy ingot at a temperature of 600° C. to 650° C. in step 1) to 1150° C. for homogenization treatment, and then repeatedly upsetting and drawing forging the ingot twice in a high-speed forging machine, with the forging ratio of the ingot in each fire being not less than 2, and the final forging temperature being not less than 950° C.;

[0114] 3) using a resistance furnace, heating the forging blank described in step 2) to 1100° C., and then repeatedly upsetting and drawing forging the blank in a high-speed forging machine for two cycles, wherein the forging ratio of each cycle is not less than 2.6, the total forging ratio is not less than 6, and the final forging temperature is not less than 900° C.;

[0115] 4) Using a resistance furnace, heat the forging blank in step 3) to T β -30℃, then repeatedly upsetting and stretching forging in a fast forging machine for 2 rounds, the forging ratio of the forging billet in each round shall not be less than 2.6, the total forging ratio shall not be less than 8, and the final forging temperature shall not be lower than 850℃;

[0116] 5) Using a resistance furnace, heat the forging blank in step 4) to T β +30℃, then repeatedly upsetting and stretching forging in a fast forging machine for 1 time, with a forging ratio of not less than 2.6 and a final forging temperature of not less than 900℃;

[0117] 6) Using a resistance furnace, heat the forging blank in step 5) to T β -90℃, then repeatedly upsetting and drawing forging for 3 times in a fast forging machine, with a total forging ratio of not less than 10 and a final forging temperature of not less than 850℃;

[0118] 7) Using a resistance furnace, heat the forging blank in step 6) to T β -60℃, then draw to Φ300mm bar in a fast forging machine, the total forging ratio is not less than 3, and the final forging temperature is not less than 850℃;

[0119] 8) Using a resistance furnace, the large-size titanium alloy bar for aviation use at 600°C-650°C in step 7) was subjected to solution aging treatment, and 1 wt% of the grain refiner prepared in Preparation Example 3 was added to the total weight of the system. The solution treatment system was T βThe temperature was kept at -30℃ for 4 hours and then cooled in oil. The aging treatment system was kept at 700℃ for 5 hours and then cooled in air. The macrostructure of the large-size titanium alloy bar for aviation use at 600℃-650℃ was fuzzy grain. Figure 1 , the microstructure is isometric, see Figure 2 .

[0120] Example 5

[0121] 1) Ingot Melting: The ingot preparation method is the same as that in Example 1, except that the diameter of the 600°C-650°C titanium alloy ingot is 540 mm;

[0122] 2) using a resistance furnace, heating the titanium alloy ingot at a temperature of 600° C. to 650° C. in step 1) to 1200° C. for homogenization treatment, and then repeatedly upsetting and drawing forging in a high-speed forging machine for one fire, with a forging ratio of not less than 2 and a final forging temperature of not less than 950° C.;

[0123] 3) using a resistance furnace, heating the forging blank described in step 2) to 1050° C., and then repeatedly upsetting and drawing forging the blank three times on a high-speed forging machine, wherein the forging ratio of each forging time is not less than 2.6, the total forging ratio is not less than 6, and the final forging temperature is not less than 900° C.;

[0124] 4) Using a resistance furnace, heat the forging blank in step 3) to T β -30℃, then repeatedly upsetting and stretching forging for 3 times in a fast forging machine, the forging ratio of the forging billet in each fire is not less than 2.6, the total forging ratio is not less than 6, and the final forging temperature is not less than 850℃;

[0125] 5) Using a resistance furnace, heat the forging blank in step 4) to T β +60℃, then repeatedly upsetting and stretching forging in a fast forging machine for 2 times, the forging ratio of the forging billet in each fire is not less than 2.6, and the final forging temperature is not less than 900℃;

[0126] 6) Using a resistance furnace, heat the forging blank in step 5) to T β -60℃, then repeatedly upsetting and drawing forging for 3 times in a fast forging machine, with a total forging ratio of not less than 10 and a final forging temperature of not less than 850℃;

[0127] 7) Using a resistance furnace, heat the forging blank in step 6) to T β -40℃, then use it in a fast forging machine to stretch the bar to Φ300mm, the total forging ratio is not less than 3, and the final forging temperature is not less than 850℃;

[0128] 8) Using a resistance furnace, the large-size titanium alloy bar for aviation use at 600°C-650°C in step 7) was subjected to solution aging treatment, and 1 wt% of the grain refiner prepared in Preparation Example 3 was added to the total weight of the system. The solution treatment system was T βKeep at -20℃ for 4 hours and then cool with oil. The aging treatment system is to keep at 680℃ for 8 hours and then cool with air.

[0129] Example 6

[0130] 1) Ingot Melting: The ingot preparation method is the same as that in Example 1, except that the diameter of the 600°C-650°C titanium alloy ingot is 620 mm;

[0131] 2) using a resistance furnace, heating the titanium alloy ingot at a temperature of 600° C. to 650° C. in step 1) to 1150° C. for homogenization treatment, and then repeatedly upsetting and stretching forging the ingot using a hydraulic press for one cycle, with a forging ratio of not less than 2 and a final forging temperature of not less than 950° C.;

[0132] 3) using a resistance furnace, heating the forging blank described in step 2) to 1080° C., and then repeatedly upsetting and stretching forging the blank twice using a hydraulic press, wherein the forging ratio of each forging blank is not less than 2.6, the total forging ratio is not less than 6, and the final forging temperature is not less than 900° C.;

[0133] 4) Using a resistance furnace, heat the forging blank in step 3) to T β -60℃, then use hydraulic press to repeatedly upsetting and drawing forging for 3 times, the forging ratio of each forging is not less than 2.6, the total forging ratio is not less than 8, and the final forging temperature is not less than 850℃;

[0134] 5) Using a resistance furnace, heat the forging blank in step 4) to T β +50℃, then use a hydraulic press to repeatedly upsetting and stretching for 2 times, the forging ratio of the forging blank in each fire is not less than 2.6, and the final forging temperature is not less than 900℃;

[0135] 6) Using a resistance furnace, heat the forging blank in step 5) to T β -40℃, then use a hydraulic press to repeatedly upsetting and stretching forging for 3 times, the total forging ratio is not less than 10, and the final forging temperature is not less than 850℃;

[0136] 7) Using a resistance furnace, heat the forging blank in step 6) to T β -60℃, then use hydraulic press to stretch to Φ300mm bar, the total forging ratio is not less than 3, and the final forging temperature is not less than 850℃;

[0137] 8) Using a resistance furnace, the large-size titanium alloy bar for aviation use at 600°C-650°C in step 7) was subjected to solution aging treatment, and 1 wt% of the grain refiner prepared in Preparation Example 3 was added to the total weight of the system. The solution treatment system was T β Keep at -40℃ for 2h and then cool with water. The aging treatment system is to keep at 720℃ for 6h and then cool with air.

[0138] Example 7

[0139] 1) Ingot Melting: The ingot preparation method is the same as that in Example 1, except that the diameter of the 600°C-650°C titanium alloy ingot is 620 mm;

[0140] 2) using a resistance furnace, heating the titanium alloy ingot at a temperature of 600° C. to 650° C. in step 1) to 1200° C. for homogenization treatment, and then repeatedly upsetting and stretching forging the ingot using a hydraulic press for one cycle, with a forging ratio of not less than 2 and a final forging temperature of not less than 950° C.;

[0141] 3) using a resistance furnace, heating the forging blank described in step 2) to 1050° C., and then repeatedly upsetting and stretching forging the blank twice using a hydraulic press, wherein the forging ratio of each forging blank is not less than 2.6, the total forging ratio is not less than 6, and the final forging temperature is not less than 900° C.;

[0142] 4) Using a resistance furnace, heat the forging blank in step 3) to T β -120℃, then use hydraulic press to repeatedly upsetting and drawing forging for 2 times, the forging ratio of each forging is not less than 2.6, the total forging ratio is not less than 8, and the final forging temperature is not less than 850℃;

[0143] 5) Using a resistance furnace, heat the forging blank in step 4) to T β +40℃, then use a hydraulic press to repeatedly upsetting and stretching for 2 fires, the forging ratio of the forging blank in each fire is not less than 2.6, and the final forging temperature is not less than 900℃;

[0144] 6) Using a resistance furnace, heat the forging blank in step 5) to T β -60℃, then use a hydraulic press to repeatedly upsetting and stretching forging for 3 times, the total forging ratio is not less than 10, and the final forging temperature is not less than 850℃;

[0145] 7) Using a resistance furnace, heat the forging blank in step 6) to T β -40℃, then use hydraulic press to stretch to Φ500mm bar, the total forging ratio is not less than 3, and the final forging temperature is not less than 850℃;

[0146] 8) Using a resistance furnace, the large-size titanium alloy bar for aviation use at 600°C-650°C in step 7) was subjected to solution aging treatment, and 1 wt% of the grain refiner prepared in Preparation Example 3 was added to the total weight of the system. The solution treatment system was T β Keep at -40℃ for 3 hours and then cool with oil. The aging treatment system is to keep at 700℃ for 2 hours and then cool with air.

[0147] Example 8

[0148] 1) Ingot Melting: The ingot preparation method is the same as that in Example 1, except that the diameter of the 600°C-650°C titanium alloy ingot is 460 mm;

[0149] 2) Using resistance furnace, the 600-650℃ titanium alloy ingot of step 1) is heated to 1200℃ homogenization treatment, then repeatedly upset, elongated forging 1 fire times by hydraulic press, the forging ratio is not less than 2, the final forging temperature is not less than 950℃;

[0150] 3) Using resistance furnace, the forging blank of step 2) is heated to 1100℃, then repeatedly upset, elongated forging 2 fire times by hydraulic press, the forging blank of each fire forging ratio is not less than 2.6, the total forging ratio is not less than 6, the final forging temperature is not less than 900℃;

[0151] 4) Using resistance furnace, the forging blank of step 3) is heated to T β -50℃, then repeatedly upset, elongated forging 3 fire times by hydraulic press, the forging blank of each fire forging ratio is not less than 2.6, the total forging ratio is not less than 8, the final forging temperature is not less than 850℃;

[0152] 5) Using resistance furnace, the forging blank of step 4) is heated to T β +30℃, then repeatedly upset, elongated forging 1 fire times by hydraulic press, the forging ratio is not less than 2.6, the final forging temperature is not less than 900℃;

[0153] 6) Using resistance furnace, the forging blank of step 5) is heated to T β -30℃, then repeatedly upset, elongated forging 3 fire times by hydraulic press, the total forging ratio is not less than 10, the final forging temperature is not less than 850℃;

[0154] 7) Using resistance furnace, the forging blank of step 6) is heated to T β -120℃, then elongated to Φ200mm bar by hydraulic press, the total forging ratio is not less than 3, the final forging temperature is not less than 850℃;

[0155] 8) Using resistance furnace, the large size bar of 600-650℃ titanium alloy for aviation of step 7) is solid solution and aging treatment, adding 1wt% of the grain refiner prepared in preparation example 3, the solid solution treatment system is T β -30℃ for 2h, then oil cooling, the aging treatment system is 690℃ for 3h, then air cooling.

[0156] Example 9

[0157] 1) Ingot melting: the preparation method of ingot is the same as example 1, the difference is that the diameter of 600-650℃ titanium alloy ingot is 540mm;

[0158] 2) Using resistance furnace, the 600-650℃ titanium alloy ingot of step 1) is heated to 1150℃ homogenization treatment, then repeatedly upset, elongated forging 1 fire times by hydraulic press, the forging ratio is not less than 2, the final forging temperature is not less than 950℃;

[0159] 3) using a resistance furnace, heating the forging blank described in step 2) to 1070° C., and then repeatedly upsetting and stretching forging the blank twice using a hydraulic press, wherein the forging ratio of each forging blank is not less than 2.6, the total forging ratio is not less than 6, and the final forging temperature is not less than 900° C.;

[0160] 4) Using a resistance furnace, heat the forging blank in step 3) to T β -30℃, then use a hydraulic press to repeatedly upsetting and stretching for 3 times, the forging ratio of the forging billet each time is not less than 2.6, the total forging ratio is not less than 8, and the final forging temperature is not less than 850℃;

[0161] 5) Using a resistance furnace, heat the forging blank in step 4) to T β +50℃, then use a hydraulic press to repeatedly upsetting and stretching for 2 times, the forging ratio of the forging blank in each fire is not less than 2.6, and the final forging temperature is not less than 900℃;

[0162] 6) Using a resistance furnace, heat the forging blank in step 5) to T β -70℃, then use hydraulic press to repeatedly upsetting and drawing forging for 3 times, the total forging ratio is not less than 10, and the final forging temperature is not less than 850℃;

[0163] 7) Using a resistance furnace, heat the forging blank in step 6) to T β -90℃, then use hydraulic press to stretch to Φ300mm bar, the total forging ratio is not less than 3, and the final forging temperature is not less than 850℃;

[0164] 8) Using a resistance furnace, the large-size titanium alloy bar for aviation use at 600°C-650°C in step 7) was subjected to solution aging treatment, and 1 wt% of the grain refiner prepared in Preparation Example 3 was added to the total weight of the system. The solution treatment system was T β Keep at -20℃ for 4 hours and then cool with oil. The aging treatment system is to keep at 690℃ for 4 hours and then cool with air.

[0165] Example 10

[0166] 1) Ingot Melting: The ingot preparation method is the same as that in Example 4, except that the diameter of the 600°C-650°C titanium alloy ingot is 680 mm;

[0167] 2) using a resistance furnace, heating the titanium alloy ingot at a temperature of 600° C. to 650° C. in step 1) to 1150° C. for homogenization treatment, and then repeatedly upsetting and drawing forging the ingot twice using a hydraulic press, with a forging ratio of not less than 2 and a final forging temperature of not less than 950° C.;

[0168] 3) using a resistance furnace, heating the forging blank of step 2) to 1100° C., and then repeatedly upsetting and stretching forging the blank twice using a hydraulic press, wherein the forging ratio of each forging blank is not less than 2.6, the total forging ratio is not less than 6, and the final forging temperature is not less than 900° C.;

[0169] 4) Using a resistance furnace, heat the forging blank in step 3) to T β -60℃, then use hydraulic press to repeatedly upsetting and drawing forging for 3 times, the forging ratio of each forging is not less than 2.6, the total forging ratio is not less than 8, and the final forging temperature is not less than 850℃;

[0170] 5) Using a resistance furnace, heat the forging blank in step 4) to T β +30℃, then use a hydraulic press to repeatedly upsetting and stretching forging for 1 time, the forging ratio is not less than 2.6, and the final forging temperature is not less than 900℃;

[0171] 6) Using a resistance furnace, heat the forging blank in step 5) to T β -30℃, then use a hydraulic press to repeatedly upsetting and stretching forging for 3 times, the total forging ratio is not less than 10, and the final forging temperature is not less than 850℃;

[0172] 7) Using a resistance furnace, heat the forging blank in step 6) to T β -60℃, then use hydraulic press to stretch to Φ400mm bar, the total forging ratio is not less than 3, and the final forging temperature is not less than 850℃;

[0173] 8) Using a resistance furnace, the large-size titanium alloy bar for aviation use at 600°C-650°C in step 7) was subjected to solution aging treatment, and 1 wt% of the grain refiner prepared in Preparation Example 3 was added to the total weight of the system. The solution treatment system was T β Keep at -40℃ for 4 hours and then cool with oil. The aging treatment system is to keep at 720℃ for 6 hours and then cool with air.

[0174] Example 11

[0175] 1) Ingot Melting: The ingot preparation method is the same as that in Example 4, except that the diameter of the 600°C-650°C titanium alloy ingot is 540 mm;

[0176] 2) using a resistance furnace, heating the titanium alloy ingot at a temperature of 600° C. to 650° C. in step 1) to 1150° C. for homogenization treatment, and then repeatedly upsetting and stretching forging the ingot using a hydraulic press for one cycle, with a forging ratio of not less than 2 and a final forging temperature of not less than 950° C.;

[0177] 3) using a resistance furnace, heating the forging blank described in step 2) to 1070° C., and then repeatedly upsetting and stretching forging the blank twice using a hydraulic press, wherein the forging ratio of each forging blank is not less than 2.6, the total forging ratio is not less than 6, and the final forging temperature is not less than 900° C.;

[0178] 4) Using a resistance furnace, heat the forging blank in step 3) to T β-30℃, then use a hydraulic press to repeatedly upsetting and stretching for 3 times, the forging ratio of the forging billet each time is not less than 2.6, the total forging ratio is not less than 8, and the final forging temperature is not less than 850℃;

[0179] 5) Using a resistance furnace, heat the forging blank in step 4) to T β +30℃, then use a hydraulic press to repeatedly upsetting and stretching for 2 times, the forging ratio of the forging blank in each fire is not less than 2.6, and the final forging temperature is not less than 900℃;

[0180] 6) Using a resistance furnace, heat the forging blank in step 5) to T β -70℃, then use hydraulic press to repeatedly upsetting and drawing forging for 3 times, the total forging ratio is not less than 10, and the final forging temperature is not less than 850℃;

[0181] 7) Using a resistance furnace, heat the forging blank in step 6) to T β -30℃, then use a hydraulic press to stretch to Φ250mm bar, the total forging ratio is not less than 3, and the final forging temperature is not less than 850℃;

[0182] 8) Using a resistance furnace, the large-size titanium alloy bar for aviation use at 600°C-650°C in step 7) was subjected to solution aging treatment, and 1 wt% of the grain refiner prepared in Preparation Example 3 was added to the total weight of the system. The solution treatment system was T β Keep at -30℃ for 2h and then cool with oil. The aging treatment system is to keep at 680℃ for 8h and then cool with air.

[0183] Example 12

[0184] 1) Ingot Melting: The ingot preparation method is the same as that in Example 4, except that the diameter of the 600°C-650°C titanium alloy ingot is 710 mm;

[0185] 2) using a resistance furnace, heating the titanium alloy ingot at a temperature of 600° C. to 650° C. in step 1) to 1150° C. for homogenization treatment, and then repeatedly upsetting and stretching forging the ingot using a hydraulic press for one cycle, with a forging ratio of not less than 2 and a final forging temperature of not less than 950° C.;

[0186] 3) using a resistance furnace, heating the forging blank described in step 2) to 1050° C., and then repeatedly upsetting and stretching forging the blank three times using a hydraulic press, wherein the forging ratio of each forging time is not less than 2.6, the total forging ratio is not less than 6, and the final forging temperature is not less than 900° C.;

[0187] 4) Using a resistance furnace, heat the forging blank in step 3) to T β -50℃, then use a hydraulic press to repeatedly upsetting and drawing forging for 3 times, the forging ratio of the forging billet in each fire is not less than 2.6, the total forging ratio is not less than 8, and the final forging temperature is not less than 850℃;

[0188] 5) Using a resistance furnace, heat the forging blank in step 4) to T β +50℃, then use a hydraulic press to repeatedly upsetting and stretching for 2 times, the forging ratio of the forging blank in each fire is not less than 2.6, and the final forging temperature is not less than 900℃;

[0189] 6) Using a resistance furnace, heat the forging blank in step 5) to T β -60℃, then use a hydraulic press to repeatedly upsetting and stretching forging for 3 times, the total forging ratio is not less than 10, and the final forging temperature is not less than 850℃;

[0190] 7) Using a resistance furnace, heat the forging blank in step 6) to T β -30℃, then use hydraulic press to stretch to Φ400mm bar, the total forging ratio is not less than 3, and the final forging temperature is not less than 850℃;

[0191] 8) Using a resistance furnace, the large-size titanium alloy bar for aviation use at 600°C-650°C in step 7) was subjected to solution aging treatment, and 1 wt% of the grain refiner prepared in Preparation Example 3 was added to the total weight of the system. The solution treatment system was T β The temperature was kept at -40℃ for 4 hours and then cooled with water. The aging treatment system was kept at 680℃ for 4 hours and then cooled with air.

[0192] Comparative Example 1

[0193] Compared with Example 4, the difference lies in the storage. The grain refiner is prepared by Comparative Preparation Example 1.

[0194] Comparative Example 2

[0195] Compared with Example 4, the difference lies in the storage. The grain refiner is prepared by Comparative Preparation Example 2.

[0196] Comparative Example 3

[0197] Compared with Example 4, the difference lies in the storage. The grain refiner is prepared by Comparative Preparation Example 3.

[0198] Comparative Example 4

[0199] Compared with Example 4, the difference lies in storage. The grain refiner is prepared by Comparative Preparation Example 4.

[0200] The mechanical properties of the large-sized titanium alloy bars for aviation use at 600°C-650°C prepared in Examples 1-12 of the present invention and Comparative Examples 1-4 are shown in Tables 1 and 2.

[0201] Table 1 Room temperature tensile properties

[0202]

[0203] Table 2 Tensile and creep properties at 600℃

[0204]

[0205] As can be seen from the table, the large-sized 600℃-650℃ titanium alloy bars for aviation use prepared using Examples 1-12 of the present invention have room temperature tensile strengths exceeding 1040 MPa, elongations exceeding 9%, and reductions of area exceeding 18%. The large-sized 600℃-650℃ titanium alloy bars for aviation use have 600℃ tensile strengths exceeding 635 MPa and elongations exceeding 15%. After thermal exposure at 600℃ / 100h, the room temperature elongation of the large-sized 600℃-650℃ titanium alloy bars for aviation use is greater than 3%, and the reduction of area is greater than 6%. The creep residual deformation at 600℃ / 150 MPa / 100h of the large-sized 600℃-650℃ titanium alloy bars for aviation use is less than 0.14%. The large-sized 600℃-650℃ titanium alloy bars for aviation use prepared using Examples of the present invention have high strength, good thermal stability, and excellent creep resistance at 600℃.

[0206] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A large-size titanium alloy bar with a temperature of 600-650°C for aviation and a method for preparing the same, characterized in that: The following steps are involved: (1) The raw material is 0-1 grade sponge titanium, and Sn, Mo, Si, and Nb are added in the form of an intermediate alloy; the alloy elements or the intermediate alloy are packaged into an alloy package, and then electrode pressing, electrode welding, and three vacuum consumable arc furnace smelting are carried out in sequence to obtain a titanium alloy ingot; or the sponge titanium, the alloy elements, and the intermediate alloy are uniformly mixed in a mixer, and then electrode pressing, electrode welding, and three vacuum consumable arc furnace smelting are carried out in sequence to obtain a titanium alloy ingot. (2) using a resistance furnace or a gas furnace with an oxidizing atmosphere to heat the titanium alloy ingot in step (1) to 1150° C. to 1200° C. for homogenization treatment, and then repeatedly upsetting and stretching the ingot using a fast forging machine or a hydraulic press; (3) using a resistance furnace or a gas furnace with an oxidizing atmosphere to heat and forge the titanium alloy forging blank described in step (2); (4) using a resistance furnace to heat the titanium alloy forging blank described in step (3), and repeatedly performing upsetting and stretching forging; (5) using a resistance furnace or a gas furnace with an oxidizing atmosphere to heat and forge the titanium alloy forging blank described in step (4); (6) using a resistance furnace to heat the titanium alloy forging blank described in step (5), and repeatedly performing upsetting and stretching forging; (7) using a resistance furnace to heat and elongate the titanium alloy forging blank described in step (6); (8) The rods described in step (7) are subjected to solution aging treatment to obtain large-sized titanium alloy rods with a temperature of 600° C. to 650° C. for aviation use.

2. The large-sized titanium alloy bar with a temperature of 600-650°C for aviation and the method for preparing the same according to claim 1, characterized in that: In step (1), Al is added as an intermediate alloy, and the insufficient part is added as pure Al; Zr and C are added in the form of sponge Zr and carbon powder respectively; the titanium alloy ingot is a 600℃-650℃ titanium alloy ingot with a size of Φ380mm to Φ720mm.

3. The large-sized titanium alloy bar with a temperature of 600-650°C for aviation and the method for preparing the same according to claim 1, characterized in that: The upsetting and drawing forging in step (2) is performed for 1 to 3 times, the forging ratio of the forging blank in each fire is not less than 2, and the final forging temperature is not lower than 950°C.

4. The large-sized titanium alloy bar with a temperature of 600-650°C for aviation and the method for preparing the same according to claim 1, characterized in that: In step (3), the steel is heated to 1050°C to 1100°C, and forged 2 to 3 times using a high-speed forging machine or a hydraulic press. The forging ratio of the forging blank in each fire is not less than 2.6, the total forging ratio is not less than 6, and the final forging temperature is not less than 900°C.

5. The large-sized titanium alloy bar with a temperature of 600-650°C for aviation and the method for preparing the same according to claim 1, characterized in that: The heating to T β -120℃~T β -30℃, where T β The temperature is the transformation temperature of the α+β / β phase, the forging is performed 2 to 3 times, the forging ratio of the forging blank in each fire is not less than 2.6, the total forging ratio is not less than 8, and the final forging temperature is not less than 850°C.

6. The large-sized titanium alloy bar with a temperature of 600-650°C for aviation and the method for preparing the same according to claim 1, characterized in that: The heating to T β +30℃~T β +60℃, where T β The temperature is the transformation temperature of the α+β / β phase, the forging is performed in 1 to 2 fires, the forging ratio of the forging blank in each fire is not less than 2.6, and the final forging temperature is not less than 900°C.

7. The large-sized titanium alloy bar with a temperature of 600-650°C for aviation and the method for preparing the same according to claim 1, characterized in that: The heating to T β -120℃~T β -30℃, where T β The temperature is the transformation temperature of α+β / β phase, the number of upsetting and drawing forging is 3 to 4 times, the forging ratio of the forging billet in each fire is not less than 2.6, the total forging ratio is not less than 10, and the final forging temperature is not less than 850℃.

8. The large-sized titanium alloy bar with a temperature of 600-650°C for aviation and the method for preparing the same according to claim 1, characterized in that: The heating to T β -120℃~T β -30℃, where T β The temperature is the transition temperature of the α+β / β phase, the steel is drawn to the required size, the total forging ratio is not less than 3, and the final forging temperature is not less than 850°C.

9. The large-sized titanium alloy bar with a temperature of 600-650°C for aviation and the method for preparing the same according to claim 1, characterized in that: The solution aging treatment system of the bar in step (8) is: the solution treatment system is T β -60℃~T β The rods are kept at -20°C for 2h to 4h and then oil-cooled or water-quenched. The aging treatment system is kept at 680°C to 720°C for 2h to 8h and then air-cooled. The size of the rods is Φ200mm to Φ500mm.

10. A large-size titanium alloy bar for aviation use at a temperature of 600-650°C, produced by the method according to any one of claims 1 to 9.

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