A method for preparing multi-specification Ti551 titanium alloy ingot

Abstract

The application discloses a multi-specification Ti551 titanium alloy ingot preparation method and belongs to the non-ferrous metal processing technical field. The composition of the Ti551 titanium alloy is as follows in terms of percentage by mass: Al 4.5%-5.5%, Mo 0.5%-2.5%, V 0.5%-1.5%, Zr 1.0%-3.0%, Cr 0.5%-1.5%, Sn 0.5%-1.5%, Fe≤0.25%, O≤0.12%, and the balance is Ti and inevitable impurities. The method comprises the following steps: proportionally weighing raw materials such as titanium sponge, zirconium sponge, Al-Mo-containing intermediate alloy, Ti-Sn-containing intermediate alloy, aluminum beans and TiO2; pressing the raw materials into electrode blocks with a density≥3.2g / cm 3 ; obtaining consumable electrodes through vacuum welding; preparing ingots through three-time vacuum consumable arc furnace smelting, the vacuum degree of the three-time smelting is all≤6Pa, and the diameter of the crucible ranges from Φ570mm to Φ1240mm. The application solves problems such as the increase of melt viscosity, poor fluidity, uneven ingot composition and the like caused by multiple alloy elements, and establishes a complete smelting process system covering 5-20-ton multi-specification ingots.

Description

Technical Field

[0001] This invention belongs to the field of non-ferrous metal processing technology, specifically relating to a method for smelting and preparing multi-specification Ti551 titanium alloy ingots. Background Technology

[0002] In recent years, the titanium and titanium alloy industry has developed rapidly, and the demand for their applications in various fields continues to increase due to their excellent properties. Titanium alloys, with their high specific strength, high toughness, excellent corrosion resistance, and superior weldability, occupy an irreplaceable position in high-end applications such as aerospace, marine engineering, and energy.

[0003] With the rapid development of marine engineering, the demand for titanium alloys in pressure-resistant components of marine submersibles and deep-sea submersibles is increasing. Currently, Ti-6Al-4V titanium alloy is one of the most widely used titanium alloys and also one of the most technologically mature, offering high production stability and making it the preferred material in many applications. However, as marine engineering has evolved, conventional Ti-6Al-4V titanium alloys can no longer meet all its application requirements.

[0004] Ti551 titanium alloy is a novel titanium alloy structural material for marine applications. Its chemical composition, by mass percentage, is as follows: Al 4.5%~5.5%, Mo 0.5%~2.5%, V 0.5%~1.5%, Zr 1.0%~3.0%, Cr 0.5%~1.5%, Sn 0.5%~1.5%, Fe≤0.25%, O≤0.12%, other individual elements≤0.10%, total other elements≤0.30%, with the balance being Ti and unavoidable impurities. Ti551 titanium alloy consists of α and β phases. Under the same yield strength conditions, its impact absorption energy is increased by approximately 20% compared to the traditional Ti80 alloy, and its manufacturing cost is reduced by more than 20%. With its low cost, high strength, high toughness, and excellent resistance to stress corrosion, it is considered an ideal structural material with broad application prospects. Its hot workability and weldability meet the forming requirements of structural components such as pressure hulls for marine equipment.

[0005] However, Ti551 titanium alloy contains six main alloying elements: Al, Mo, V, Zr, Cr, and Sn. The following technical challenges exist during smelting: the multiple alloying elements increase the viscosity of the melt and reduce its fluidity, leading to defects such as porosity, shrinkage cavities, and uneven microstructure in the ingots; at the same time, different specifications of ingots have significantly different requirements for process parameters such as smelting time, smelting current, smelting voltage, and holding time, making it difficult to determine the process route. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a method for preparing Ti551 titanium alloy ingots of various specifications. By selecting appropriate raw materials and alloy ratios, and through three vacuum consumable arc furnace melting processes, Ti551 titanium alloy ingots are obtained, solving the problem of uneven composition caused by multiple alloying elements, and establishing a complete melting process system covering ingots of different specifications.

[0007] The technical solution adopted in this invention is as follows:

[0008] A method for preparing multi-specification Ti551 titanium alloy ingots includes the following steps:

[0009] Step 1: Weigh the raw materials according to the proportions. The raw materials include sponge titanium, sponge zirconium, Al-Mo master alloy, Ti-Sn master alloy, aluminum briquettes, and TiO2, and prepare Ti551 titanium alloy. By mass percentage, Al 4.5%~5.5%, Mo 0.5%~2.5%, V 0.5%~1.5%, Zr 1.0%~3.0%, Cr 0.5%~1.5%, Sn 0.5%~1.5%, Fe≤0.25%, O≤0.12%, and the balance is Ti and unavoidable impurities.

[0010] Step 2: Press the uniformly mixed raw materials into consumable electrode blocks. The density of the pressed electrode blocks should be ≥3.2 g / cm³. 3 ;

[0011] Step 3: After arranging and fixing the electrode blocks, send them into the vacuum welding box for welding to obtain a consumable electrode. Before welding, evacuate to ≤5Pa and the leakage rate ≤1.3Pa / min.

[0012] Step 4: Perform three vacuum consumable arc furnace melting processes on the primary consumable electrode, specifically as follows:

[0013] The parameters for the first vacuum self-consumption melting are: melting vacuum ≤ 6Pa, leakage rate ≤ 0.9Pa / min, melting current 12kA~30kA, melting voltage 20V~40V;

[0014] The parameters for the second vacuum self-consumption melting are: melting vacuum ≤ 4Pa, leakage rate ≤ 0.71Pa / min, melting current 14kA~32kA, melting voltage 25V~40V;

[0015] The third vacuum self-consumption melting is the finished product melting, and the melting parameters meet the following requirements: melting vacuum ≤3Pa, leakage rate ≤0.65Pa / min, melting current 14kA~34kA, melting voltage 30V~40V;

[0016] Among them, the corresponding crucible size is selected according to the target ingot specifications, and the crucible diameter range is Φ570mm~Φ1240mm.

[0017] Furthermore, the target composition of the Ti551 titanium alloy, by mass percentage, is: Al: 5%, Mo: 1.5%, Sn: 1%, V: 1%, Cr: 1%, Zr: 2%, Fe: 0.15%, O: 0.09%, with the balance being Ti and unavoidable impurities.

[0018] Furthermore, the Al-Mo-containing master alloy is selected from one or more of Al-Mo-V-Cr master alloy, Al-Mo master alloy, or Al-Sn-Zr-Mo-Cr master alloy.

[0019] Furthermore, the raw materials also include Al-Fe master alloy or iron nails.

[0020] Furthermore, in step three, the welding current is 300A~600A and the welding voltage is 30V~70V.

[0021] Furthermore, when preparing the Φ720mm finished ingot, the crucible dimensions for the three melting processes are Φ570mm, Φ650mm, and Φ720mm respectively; the parameters for the first vacuum consumable melting are: melting current 12kA~18kA, melting voltage 20V~40V; the parameters for the second vacuum consumable melting are: melting current 14kA~22kA, melting voltage 20V~40V; and the parameters for the third vacuum consumable melting are: melting current 14kA~24kA, melting voltage 30V~40V.

[0022] Furthermore, the preparation of the Φ960mm finished ingot includes the following steps: The electrode blocks are arranged, fixed, and welded in two stages to obtain two primary consumable electrodes; the two primary consumable electrodes undergo a first vacuum consumable melting process to obtain two primary ingots. The first melting crucible is Φ820mm, the melting current is 16kA~26kA, and the melting voltage is 30V~40V; the two primary ingots are cleaned, flattened, and chamfered, and then butt-welded in a vacuum consumable arc furnace; the butt-welded ingots undergo a second vacuum consumable melting process, with a crucible of Φ890mm, a melting current of 18kA~28kA, and a melting voltage of 25V~40V; a third vacuum consumable melting process is performed, with a crucible of Φ960mm, a melting current of 20kA~30kA, and a melting voltage of 30V~40V.

[0023] Furthermore, the preparation of the Φ1240mm finished ingot includes the following steps: The electrode blocks are arranged, fixed, and welded in two stages to obtain two primary consumable electrodes; the two primary consumable electrodes undergo a first vacuum consumable melting process to obtain two primary ingots. The first melting crucible is Φ960mm, the melting current is 20kA~30kA, and the melting voltage is 30V~40V; the two primary ingots are cleaned, flattened, and chamfered, and then butt-welded in a vacuum consumable arc furnace; the butt-welded ingots undergo a second vacuum consumable melting process, with a crucible of Φ1170mm, a melting current of 22kA~32kA, and a melting voltage of 30V~40V; a third vacuum consumable melting process is performed, with a crucible of Φ1240mm, a melting current of 24kA~34kA, and a melting voltage of 30V~40V.

[0024] Furthermore, the welding parameters for the butt welding are: vacuuming to ≤7Pa, leakage rate ≤2.8Pa / min, welding current 3kA~18kA, and welding voltage 20V~40V.

[0025] Furthermore, the density of the pressed electrode block is 3.2 g / cm³. 3 ~3.4g / cm 3 .

[0026] The beneficial effects of this invention are:

[0027] 1) The addition of multi-element master alloys makes Ti551 titanium alloy have excellent mechanical properties, which can meet the requirements of marine engineering for high-performance titanium alloys.

[0028] 2) Multi-specification ingots include ingots ranging from 5 tons to 20 tons. Large-specification ingots are suitable for large components, reducing the need for welding and splicing. The material properties are more uniform, which can better meet the downstream processing needs and solve the problem of large differences in the requirements for ingot size and weight.

[0029] 3) Multiple vacuum self-consuming electric arc furnace melting and supporting melting processes can solve the adverse effects of multiple intermediate alloying elements on ingot melting;

[0030] 4) The Ti551 titanium alloy ingot produced by this invention meets the research and development requirements. The determined process route and smelting process can produce Ti551 titanium alloy ingots with uniform composition. The titanium material produced meets the performance requirements and has no metallurgical defects such as porosity, inclusions and segregation in high and low magnification structures. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of longitudinal sampling of ingots;

[0032] Figure 2 This is a schematic diagram of sampling the cut surface of the ingot riser;

[0033] Figure 3 The results of longitudinal 5-point compositional analysis of the ingot in Example 1 are shown.

[0034] Figure 4 The results of compositional analysis at 9 points on the cut surface of the ingot riser in Example 1 are shown.

[0035] Figure 5 The results of longitudinal 5-point compositional analysis of the ingot in Example 2 are shown.

[0036] Figure 6 The results of compositional analysis at 9 points on the cut surface of the ingot riser in Example 2 are shown.

[0037] Figure 7 The results of longitudinal 5-point compositional analysis of the ingot in Example 3 are shown.

[0038] Figure 8 The results of compositional analysis at 9 points on the cut surface of the ingot riser in Example 3 are shown.

[0039] Figure 9 The results of longitudinal 5-point compositional analysis of the ingot in Example 4 are shown.

[0040] Figure 10 The results of compositional analysis at 9 points on the cut surface of the ingot riser in Example 4 are shown.

[0041] Figure 11 The results of longitudinal 5-point compositional analysis of the ingot in Example 5;

[0042] Figure 12 The results of compositional analysis at 9 points on the cut surface of the ingot riser in Example 5;

[0043] Figure 13 The results of longitudinal 5-point compositional analysis of the ingot in Example 6;

[0044] Figure 14 The results of compositional analysis at 9 points on the cut surface of the ingot riser in Example 6 are shown.

[0045] Figure 15 The results of longitudinal 5-point compositional analysis of the ingot in Example 7 are shown.

[0046] Figure 16 The results of compositional analysis at 9 points on the cut surface of the ingot riser in Example 7 are shown.

[0047] Figure 17 The results of longitudinal 5-point compositional analysis of the ingot in Example 8;

[0048] Figure 18 The results of compositional analysis at 9 points on the cut surface of the ingot riser in Example 8 are shown. Detailed Implementation

[0049] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0050] Example 1

[0051] The specific steps for preparing a Φ720mm Ti551 titanium alloy ingot in this embodiment are as follows:

[0052] Step 1: Weigh the raw materials of the titanium alloy according to the proportions. Weighing the sponge titanium, sponge zirconium, Al-Mo-V-Cr, Al-Mo, Al-Fe, Ti-Sn master alloy, aluminum briquettes and TiO2 can produce Al: 5%, Mo: 1.5%, Sn: 1%, V: 1%, Cr: 1%, Zr: 2%, Fe: 0.15%, O: 0.09%, with the remainder being Ti and unavoidable impurities.

[0053] Step two involves transporting the uniformly mixed raw materials to a hydraulic press to press them into consumable electrode blocks. The pressing pressure must be such that the density of the pressed electrode blocks is ≥3.2 g / cm³. 3 .

[0054] Step 3: Place the electrode blocks from Step 2 into the material rack, arrange them in a row, connect them tightly, and fix them in place. Then, send them into the vacuum welding box for welding to obtain a consumable electrode. Before welding, the vacuum is evacuated to ≤5Pa, the leakage rate is ≤1.3Pa / min, the welding current is 300A~600A, and the welding voltage is 50V~70V.

[0055] Step four involves performing three vacuum melting processes on the consumable electrode from step three, specifically as follows:

[0056] The parameters for the first vacuum self-consumable melting are: crucible Φ570mm, melting vacuum ≤5Pa, leakage rate ≤0.85Pa / min, melting current 12kA~18kA, melting voltage 20V~40V;

[0057] The parameters for the second vacuum self-consumption melting are: crucible Φ650mm, melting vacuum ≤5Pa, leakage rate ≤0.63Pa / min, melting current 14kA~22kA, melting voltage 20V~40V;

[0058] The third vacuum self-consumable melting is the finished product melting, and the melting parameters meet the following requirements: crucible Φ720mm, melting vacuum ≤3Pa, leakage rate ≤0.54Pa / min, melting current 14kA~24kA, melting voltage 30V~40V.

[0059] To verify the compositional uniformity of the Ti551 titanium alloy ingot of this invention, compositional analysis was performed at five points along the longitudinal direction of the ingot and nine points on the riser cut surface. A schematic diagram of the sampling is shown below. Figure 1 and Figure 2 . Figure 3 The results of longitudinal 5-point compositional analysis of the ingot in Example 1 are as follows. Figure 4The figure shows the compositional analysis results of 9 points on the cut surface of the ingot riser in Example 1. As can be seen from the figure, the compositional uniformity of the ingot in the longitudinal and radial directions is good, which meets the relevant standard requirements.

[0060] Example 2

[0061] The specific steps for preparing a Φ720mm Ti551 titanium alloy ingot in this embodiment are as follows:

[0062] Step 1: Weigh the raw materials of the titanium alloy according to the proportions. Weighing the sponge titanium, sponge zirconium, Al-Sn-Zr-Mo-Cr, Al-Mo, Ti-Sn master alloy, as well as aluminum briquettes, iron nails and TiO2, can produce Al: 5%, Mo: 1.5%, Sn: 1%, V: 1%, Cr: 1%, Zr: 2%, Fe: 0.15%, O: 0.09%, with the remainder being Ti and unavoidable impurities.

[0063] Step two: The uniformly mixed raw materials are transported to a hydraulic press and pressed into consumable electrode blocks. The pressing pressure requires the density of the electrode blocks after pressing to be ≥3.3 g / cm³. 3 .

[0064] Step 3: Place the electrode blocks from Step 2 into the material rack, arrange them in a row, connect them tightly, and fix them in place. Then, send them into the vacuum welding box for welding to obtain a consumable electrode. Before welding, the vacuum is evacuated to ≤4Pa, the leakage rate is ≤1.0Pa / min, the welding current is 400A~600A, and the welding voltage is 55V~70V.

[0065] Step four involves performing three vacuum melting processes on the consumable electrode from step three, specifically as follows:

[0066] The parameters for the first vacuum self-consumable melting are: crucible Φ570mm, melting vacuum ≤5Pa, leakage rate ≤0.8Pa / min, melting current 12kA~18kA, melting voltage 30V~40V;

[0067] The parameters for the second vacuum self-consumption melting are: crucible Φ650mm, melting vacuum ≤4Pa, leakage rate ≤0.71Pa / min, melting current 14kA~22kA, melting voltage 30V~40V;

[0068] The third vacuum self-consumable melting is the finished product melting, and the melting parameters meet the following requirements: crucible Φ720mm, melting vacuum ≤3Pa, leakage rate ≤0.5Pa / min, melting current 14kA~24kA, melting voltage 30V~40V.

[0069] To verify the compositional uniformity of the Ti551 titanium alloy ingot of this invention, compositional analysis was performed at five points along the longitudinal direction of the ingot and nine points on the riser cut surface. A schematic diagram of the sampling is shown below. Figure 1 and Figure 2 . Figure 5 The results of longitudinal 5-point compositional analysis of the ingot in Example 2 are as follows. Figure 6 The figure shows the compositional analysis results of 9 points on the cut surface of the ingot riser in Example 2. As can be seen from the figure, the compositional uniformity of the ingot in the longitudinal and radial directions is good, which meets the relevant standard requirements.

[0070] Example 3

[0071] The specific steps for preparing a Φ960mm Ti551 titanium alloy ingot in this embodiment are as follows:

[0072] Step 1: Weigh the raw materials of the titanium alloy according to the proportions. Weighing the sponge titanium, sponge zirconium, Al-Mo-V-Cr, Al-Mo, Al-Fe, Ti-Sn master alloy, aluminum briquettes and TiO2 can produce Al: 5%, Mo: 1.5%, Sn: 1%, V: 1%, Cr: 1%, Zr: 2%, Fe: 0.15%, O: 0.09%, with the remainder being Ti and unavoidable impurities.

[0073] Step two: The uniformly mixed raw materials are transported to a hydraulic press and pressed into consumable electrode blocks. The pressing pressure requires the density of the electrode blocks after pressing to be ≥3.3 g / cm³. 3 .

[0074] Step 3: Place the electrode blocks from Step 2 into the material rack in two batches, arrange them in a row, connect them tightly, and fix them in place. Then, send them into a vacuum argon-filled plasma arc welding box for connection to obtain two primary consumable electrodes. Before welding, the vacuum level is ≤5Pa, the leakage rate is ≤1.1Pa / min, the welding current is 400A~600A, and the welding voltage is 30V~65V.

[0075] Step four: Perform a vacuum melting process on the two primary consumable electrodes from step three to obtain two primary ingots. The parameters for the first vacuum consumable melting process are: crucible Φ820mm, melting vacuum ≤6Pa, leakage rate ≤0.74Pa / min, melting current 16kA~26kA, and melting voltage 30V~40V.

[0076] Step 5: Clean the two primary casting ingots, flatten their ends, and chamfer them. Then, place them in a vacuum arc furnace for butt welding. Specifically, place the first ingot bottom-down and top-up into an 890mm crucible, and connect the second ingot bottom-down to the top of the first. The welding parameters are: vacuum to ≤6Pa, leakage rate ≤2.5Pa / min, welding current 3kA~12kA, and welding voltage 20V~40V.

[0077] Step six: The ingot welded in step five is subjected to a second vacuum arc remelting process to obtain a secondary ingot with a diameter of 890mm. The parameters for the second vacuum arc remelting are: crucible diameter 890mm, melting vacuum ≤3Pa, leakage rate ≤0.6Pa / min, melting current 18kA~28kA, and melting voltage 25V~40V.

[0078] Step seven involves subjecting the secondary ingot from step six to a third vacuum arc remelting process to obtain a Φ960mm tertiary finished ingot. The third vacuum arc remelting is the final product melting process, and the melting parameters meet the following requirements: crucible Φ960mm, melting vacuum ≤3Pa, leakage rate ≤0.5Pa / min, melting current 20kA~30kA, and melting voltage 30V~40V.

[0079] To verify the compositional uniformity of the Ti551 titanium alloy ingot of this invention, compositional analysis was performed at five points along the longitudinal direction of the ingot and nine points on the riser cut surface. A schematic diagram of the sampling is shown below. Figure 1 and Figure 2 . Figure 7 The results of longitudinal 5-point compositional analysis of the ingot in Example 3 are as follows. Figure 8 The figure shows the compositional analysis results of 9 points on the cut surface of the ingot riser in Example 3. As can be seen from the figure, the compositional uniformity of the ingot in the longitudinal and radial directions is good, which meets the relevant standard requirements.

[0080] Example 4

[0081] The specific steps for preparing a Φ960mm Ti551 titanium alloy ingot in this embodiment are as follows:

[0082] Step 1: Weigh the raw materials of titanium alloy according to the proportions. By weighing sponge titanium, sponge zirconium, Al-Sn-Zr-Mo-Cr, Al-Mo, Ti-Sn master alloy, as well as aluminum briquettes, iron nails and TiO2, an ingot with Al: 5%, Mo: 1.5%, Sn: 1%, V: 1%, Cr: 1%, Zr: 2%, Fe: 0.15%, O: 0.09%, and the remainder being Ti can be produced.

[0083] Step two: The uniformly mixed raw materials are transported to a hydraulic press and pressed into consumable electrode blocks. The pressing pressure requires the density of the electrode blocks after pressing to be ≥3.3 g / cm³. 3 .

[0084] Step 3: Place the electrode blocks from Step 2 into the material rack in two batches, arrange them in a row, connect them tightly, and fix them in place. Then, send them into the vacuum welding box for welding to obtain two primary consumable electrodes. Before welding, the vacuum level is ≤5Pa, the leakage rate is ≤1.0Pa / min, the welding current is 300A~600A, and the welding voltage is 40V~70V.

[0085] Step four: Perform a vacuum melting process on the two primary consumable electrodes from step three to obtain two primary ingots. The parameters for the first vacuum consumable melting process are: crucible Φ820mm, melting vacuum ≤5Pa, leakage rate ≤0.8Pa / min, melting current 16kA~26kA, and melting voltage 30V~40V.

[0086] Step 5: Clean the two primary casting ingots, flatten their ends, and chamfer them. Then, place them in a vacuum arc furnace for butt welding. Specifically, place the first ingot bottom-down and top-up into an 890mm crucible, and connect the second ingot bottom-down to the top of the first. The welding parameters are: vacuum to ≤5Pa, leakage rate ≤2.0Pa / min, welding current 3kA~14kA, and welding voltage 20V~40V.

[0087] Step six: The ingot welded in step five is subjected to a second vacuum arc remelting process to obtain a secondary ingot with a diameter of 890mm. The parameters for the second vacuum arc remelting are: crucible diameter 890mm, melting vacuum ≤3Pa, leakage rate ≤0.6Pa / min, melting current 18kA~28kA, and melting voltage 30V~40V.

[0088] Step seven involves subjecting the secondary ingot from step six to a third vacuum arc remelting process to obtain a Φ960mm tertiary finished ingot. The third vacuum arc remelting is the final product melting process, and the melting parameters meet the following requirements: crucible Φ960mm, melting vacuum ≤3Pa, leakage rate ≤0.6Pa / min, melting current 20kA~30kA, and melting voltage 30V~40V.

[0089] To verify the compositional uniformity of the Ti551 titanium alloy ingot of this invention, compositional analysis was performed at five points along the longitudinal direction of the ingot and nine points on the riser cut surface. A schematic diagram of the sampling is shown below. Figure 1 and Figure 2 . Figure 9 The results of longitudinal 5-point compositional analysis of the ingot in Example 4 are as follows. Figure 10 The figure shows the compositional analysis results of 9 points on the cut surface of the ingot riser in Example 4. As can be seen from the figure, the compositional uniformity of the ingot in the longitudinal and radial directions is good, which meets the relevant standard requirements.

[0090] Example 5

[0091] The specific steps for preparing a Φ1240mm Ti551 titanium alloy ingot in this embodiment are as follows:

[0092] Step 1: Weigh the raw materials of the titanium alloy according to the proportions. Weighing the sponge titanium, sponge zirconium, Al-Mo-V-Cr, Al-Mo, Al-Fe, Ti-Sn master alloy, aluminum briquettes and TiO2 can produce Al: 5%, Mo: 1.5%, Sn: 1%, V: 1%, Cr: 1%, Zr: 2%, Fe: 0.15%, O: 0.09%, with the remainder being Ti and unavoidable impurities.

[0093] Step two involves transporting the uniformly mixed raw materials to a hydraulic press to press them into consumable electrode blocks. The pressing pressure must be such that the density of the pressed electrode blocks is ≥3.4 g / cm³. 3 .

[0094] Step 3: Place the electrode blocks from Step 2 into the material rack in two separate steps, arranging them in two tightly connected rows and fixing them in place. Then, send them into the vacuum welding box for welding to obtain two primary consumable electrodes. Before welding, the vacuum level is ≤5Pa, the leakage rate is ≤0.9Pa / min, the welding current is 400A~600A, and the welding voltage is 30V~70V.

[0095] Step four: Perform a vacuum melting process on the two primary consumable electrodes from step three to obtain two primary ingots. The parameters for the first vacuum consumable melting process are: crucible Φ960mm, melting vacuum ≤5Pa, leakage rate ≤0.78Pa / min, melting current 20kA~30kA, and melting voltage 30V~40V.

[0096] Step 5: Clean the two primary casting ingots, flatten their ends, and chamfer them. Then, place them in a vacuum arc furnace for butt welding. Specifically, place the first ingot bottom-down and top-up into a Φ1170mm crucible, and connect the second ingot bottom-down to the top of the first. The welding parameters are: vacuum to ≤5Pa, leakage rate ≤2.0Pa / min, welding current 3kA~18kA, and welding voltage 20V~40V.

[0097] Step six involves secondary vacuum arc remelting of the ingot welded in step five to obtain a secondary ingot with a diameter of 1170mm. The parameters for the second vacuum arc remelting are: crucible Φ1170mm, melting vacuum ≤3Pa, leakage rate ≤0.52Pa / min, melting current 22kA~32kA, and melting voltage 30V~40V.

[0098] Step seven involves subjecting the secondary ingot from step six to a third vacuum arc remelting process to obtain a Φ1240mm tertiary finished ingot. The third vacuum arc remelting is the final product melting process, and the melting parameters meet the following requirements: crucible Φ1240mm, melting vacuum ≤3Pa, leakage rate ≤0.65Pa / min, melting current 24kA~34kA, and melting voltage 30V~40V.

[0099] To verify the compositional uniformity of the Ti551 titanium alloy ingot of this invention, compositional analysis was performed at five points along the longitudinal direction of the ingot and nine points on the riser cut surface. A schematic diagram of the sampling is shown below. Figure 1 and Figure 2 . Figure 11 The results of longitudinal 5-point compositional analysis of the ingot in Example 5 are as follows. Figure 12 The figure shows the compositional analysis results of 9 points on the cut surface of the ingot riser in Example 5. As can be seen from the figure, the compositional uniformity of the ingot in the longitudinal and radial directions is good, which meets the relevant standard requirements.

[0100] Example 6

[0101] The specific steps for preparing a Φ1240mm Ti551 titanium alloy ingot in this embodiment are as follows:

[0102] Step 1: Weigh the raw materials of the titanium alloy according to the proportions. Weighing the sponge titanium, sponge zirconium, Al-Sn-Zr-Mo-Cr, Al-Mo, Ti-Sn master alloy, as well as aluminum briquettes, iron nails and TiO2, can produce Al: 5%, Mo: 1.5%, Sn: 1%, V: 1%, Cr: 1%, Zr: 1%, Fe: 0.15%, O: 0.09%, with the remainder being Ti and unavoidable impurities.

[0103] Step two: The uniformly mixed raw materials are transported to a hydraulic press and pressed into consumable electrode blocks. The pressing pressure requires the density of the electrode blocks after pressing to be ≥3.3 g / cm³. 3 .

[0104] Step 3: Place the electrode blocks from Step 2 into the material rack in two separate steps, arranging them in two tightly connected rows and fixing them in place. Then, send them into the vacuum welding box for welding to obtain two primary consumable electrodes. Before welding, the vacuum level is ≤5Pa, the leakage rate is ≤1.0Pa / min, the welding current is 400A~600A, and the welding voltage is 30V~70V.

[0105] Step four: Perform a vacuum melting process on the two primary consumable electrodes from step three to obtain two primary ingots. The parameters for the first vacuum consumable melting process are: crucible Φ960mm, melting vacuum ≤5Pa, leakage rate ≤0.90Pa / min, melting current 20kA~30kA, and melting voltage 30V~40V.

[0106] Step 5: Clean the two primary casting ingots, flatten their ends, and chamfer them. Then, place them in a vacuum arc furnace for butt welding. Specifically, place the first ingot bottom-down and top-up into a Φ1170mm crucible, and connect the second ingot bottom-down to the top of the first. The welding parameters are: vacuum to ≤7Pa, leakage rate ≤2.8Pa / min, welding current 3kA~15kA, welding voltage 20V~40V.

[0107] Step six involves secondary vacuum arc remelting of the ingot welded in step five to obtain a secondary ingot with a diameter of 1170mm. The parameters for the second vacuum arc remelting are: crucible Φ1170mm, melting vacuum ≤3Pa, leakage rate ≤0.64Pa / min, melting current 22kA~32kA, and melting voltage 30V~40V.

[0108] Step seven involves subjecting the secondary ingot from step six to a third vacuum arc remelting process to obtain a Φ1240mm tertiary finished ingot. The third vacuum arc remelting is the final product melting process, and the melting parameters meet the following requirements: crucible Φ1240mm, melting vacuum ≤3Pa, leakage rate ≤0.54Pa / min, melting current 24kA~34kA, and melting voltage 30V~40V.

[0109] To verify the compositional uniformity of the Ti551 titanium alloy ingot of this invention, compositional analysis was performed at five points along the longitudinal direction of the ingot and nine points on the riser cut surface. A schematic diagram of the sampling is shown below. Figure 1 and Figure 2 . Figure 13 The results of longitudinal 5-point compositional analysis of the ingot in Example 6 are as follows. Figure 14 The figure shows the compositional analysis results of 9 points on the cut surface of the ingot riser in Example 6. As can be seen from the figure, the compositional uniformity of the ingot in the longitudinal and radial directions is good, which meets the relevant standard requirements.

[0110] Example 7

[0111] This embodiment prepares a Φ720mm Ti551 titanium alloy ingot using the lower limit of the composition ratio. The specific steps are as follows:

[0112] Step 1: Weigh the raw materials of titanium alloy according to the proportions. Weighing sponge titanium, sponge zirconium, Al-Mo-V-Cr, Al-Mo, Al-Fe, Ti-Sn master alloy, aluminum briquettes and TiO2 can produce Al: 4.5%, Mo: 0.5%, Sn: 0.5%, V: 0.5%, Cr: 0.5%, Zr: 1%, with the remainder being Ti and unavoidable impurities.

[0113] Step two involves transporting the uniformly mixed raw materials to a hydraulic press to press them into consumable electrode blocks. The pressing pressure must be such that the density of the pressed electrode blocks is ≥3.2 g / cm³. 3 .

[0114] Step 3: Place the electrode blocks from Step 2 into the material rack, arrange them in a row, connect them tightly, and fix them in place. Then, send them into the vacuum welding box for welding to obtain a consumable electrode. Before welding, the vacuum is evacuated to ≤5Pa, the leakage rate is ≤1.3Pa / min, the welding current is 300A~600A, and the welding voltage is 50V~70V.

[0115] Step four involves performing three vacuum melting processes on the consumable electrode from step three, specifically as follows:

[0116] The parameters for the first vacuum self-consumable melting are: crucible Φ570mm, melting vacuum ≤5Pa, leakage rate ≤0.85Pa / min, melting current 12kA~18kA, melting voltage 20V~40V;

[0117] The parameters for the second vacuum self-consumption melting are: crucible Φ650mm, melting vacuum ≤4Pa, leakage rate ≤0.63Pa / min, melting current 14kA~22kA, melting voltage 20V~40V;

[0118] The third vacuum self-consumable melting is the finished product melting, and the melting parameters meet the following requirements: crucible Φ720mm, melting vacuum ≤3Pa, leakage rate ≤0.54Pa / min, melting current 14kA~24kA, melting voltage 30V~40V.

[0119] To verify the compositional uniformity of the Ti551 titanium alloy ingot of this invention, compositional analysis was performed at five points along the longitudinal direction of the ingot and nine points on the riser cut surface. A schematic diagram of the sampling is shown below. Figure 1 and Figure 2 . Figure 15 The results of longitudinal 5-point compositional analysis of the ingot in Example 7 are as follows. Figure 16 The figure shows the compositional analysis results of 9 points on the cut surface of the ingot riser in Example 7. As can be seen from the figure, the compositional uniformity of the ingot in the longitudinal and radial directions is good, which meets the relevant standard requirements.

[0120] Example 8

[0121] This embodiment prepares a Φ960mm Ti551 titanium alloy ingot using the upper limit of the composition ratio. The specific steps are as follows:

[0122] Step 1: Weigh the raw materials of titanium alloy according to the proportions. Weighing sponge titanium, sponge zirconium, Al-Sn-Zr-Mo-Cr, Al-Mo, Ti-Sn master alloy, as well as aluminum briquettes, iron nails and TiO2, can produce Al: 5.5%, Mo: 2.5%, Sn: 1.5%, V: 1.5%, Cr: 1.5%, Zr: 3.0%, with the remainder being Ti and unavoidable impurities.

[0123] Step two involves transporting the uniformly mixed raw materials to a hydraulic press to press them into consumable electrode blocks. The pressing pressure must be such that the density of the pressed electrode blocks is ≥3.4 g / cm³. 3 .

[0124] Step 3: Place the electrode blocks from Step 2 into the material rack in two batches, arrange them in a row, connect them tightly, and fix them in place. Then, send them into the vacuum welding box for welding to obtain two primary consumable electrodes. Before welding, the vacuum level is ≤5Pa, the leakage rate is ≤1.0Pa / min, the welding current is 400A~600A, and the welding voltage is 40V~70V.

[0125] Step four: Perform a vacuum melting process on the two primary consumable electrodes from step three to obtain two primary ingots. The parameters for the first vacuum consumable melting process are: crucible Φ820mm, melting vacuum ≤6Pa, leakage rate ≤0.8Pa / min, melting current 16kA~26kA, and melting voltage 30V~40V.

[0126] Step 5: Clean the two primary casting ingots, flatten their ends, and chamfer them. Then, place them in a vacuum arc furnace for butt welding. Specifically, place the first ingot bottom-down and top-up into an 890mm crucible, and connect the second ingot bottom-down to the top of the first. The welding parameters are: vacuum to ≤6Pa, leakage rate ≤2.5Pa / min, welding current 3kA~14kA, and welding voltage 20V~40V.

[0127] Step six: The ingot welded in step five is subjected to a second vacuum arc remelting process to obtain a secondary ingot with a diameter of 890mm. The parameters for the second vacuum arc remelting are: crucible diameter 890mm, melting vacuum ≤3Pa, leakage rate ≤0.6Pa / min, melting current 18kA~28kA, and melting voltage 25V~40V.

[0128] Step seven involves subjecting the secondary ingot from step six to a third vacuum arc remelting process to obtain a Φ960mm tertiary finished ingot. The third vacuum arc remelting is the final product melting process, and the melting parameters meet the following requirements: crucible Φ960mm, melting vacuum ≤3Pa, leakage rate ≤0.6Pa / min, melting current 20kA~30kA, and melting voltage 30V~40V.

[0129] To verify the compositional uniformity of the Ti551 titanium alloy ingot of this invention, compositional analysis was performed at five points along the longitudinal direction of the ingot and nine points on the riser cut surface. A schematic diagram of the sampling is shown below. Figure 1 and Figure 2 . Figure 17 The results of longitudinal 5-point compositional analysis of the ingot in Example 8 are as follows. Figure 18 The figure shows the compositional analysis results of 9 points on the cut surface of the ingot riser in Example 8. As can be seen from the figure, the compositional uniformity of the ingot in the longitudinal and radial directions is good, which meets the relevant standard requirements.

[0130] As can be seen from Examples 1-8, the Ti551 titanium alloy ingots with specifications of Φ720mm~Φ1240mm produced by the method of the present invention have good uniformity of chemical composition in both the longitudinal and radial directions within the composition range of Al 4.5%~5.5%, Mo 0.5%~2.5%, V 0.5%~1.5%, Zr 1.0%~3.0%, Cr 0.5%~1.5%, and Sn 0.5%~1.5%.

[0131] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing multi-specification Ti551 titanium alloy ingots, characterized in that, Includes the following steps: Step 1: Weigh the raw materials according to the proportions. The raw materials include sponge titanium, sponge zirconium, Al-Mo master alloy, Ti-Sn master alloy, aluminum briquettes, and TiO2, and prepare Ti551 titanium alloy. By mass percentage, Al 4.5%~5.5%, Mo 0.5%~2.5%, V 0.5%~1.5%, Zr 1.0%~3.0%, Cr 0.5%~1.5%, Sn 0.5%~1.5%, Fe≤0.25%, O≤0.12%, and the balance is Ti and unavoidable impurities. Step 2: Press the uniformly mixed raw materials into consumable electrode blocks. The density of the pressed electrode blocks should be ≥3.2 g / cm³. 3 ; Step 3: After arranging and fixing the electrode blocks, send them into the vacuum welding box for welding to obtain a consumable electrode. Before welding, evacuate to ≤5Pa and the leakage rate ≤1.3Pa / min. Step 4: Perform three vacuum consumable arc furnace melting processes on the primary consumable electrode, specifically as follows: The parameters for the first vacuum self-consumption melting are: melting vacuum ≤ 6Pa, leakage rate ≤ 0.9Pa / min, melting current 12kA~30kA, melting voltage 20V~40V; The parameters for the second vacuum self-consumption melting are: melting vacuum ≤ 4Pa, leakage rate ≤ 0.71Pa / min, melting current 14kA~32kA, melting voltage 25V~40V; The third vacuum self-consumption melting is the finished product melting, and the melting parameters meet the following requirements: melting vacuum ≤3Pa, leakage rate ≤0.65Pa / min, melting current 14kA~34kA, melting voltage 30V~40V; Among them, the corresponding crucible size is selected according to the target ingot specifications, and the crucible diameter range is Φ570mm~Φ1240mm.

2. The method for preparing multi-specification Ti551 titanium alloy ingots according to claim 1, characterized in that, The composition of the Ti551 titanium alloy by mass percentage is as follows: Al 4.5%~5.5%, Mo 0.5%~2.5%, V 0.5%~1.5%, Zr 1.0%~3.0%, Cr 0.5%~1.5%, Sn 0.5%~1.5%, Fe≤0.25%, O≤0.12%, with the balance being Ti and unavoidable impurities.

3. The method for preparing multi-specification Ti551 titanium alloy ingots according to claim 1 or 2, characterized in that, The Al-Mo-containing master alloy is selected from one or more of Al-Mo-V-Cr master alloy, Al-Mo master alloy, or Al-Sn-Zr-Mo-Cr master alloy.

4. The method for preparing multi-specification Ti551 titanium alloy ingots according to claim 1 or 2, characterized in that, The raw materials also include Al-Fe master alloy or iron nails.

5. The method for preparing multi-specification Ti551 titanium alloy ingots according to claim 1 or 2, characterized in that, In step three, the welding current is 300A~600A and the welding voltage is 30V~70V.

6. The method for preparing multi-specification Ti551 titanium alloy ingots according to claim 1 or 2, characterized in that, When preparing a Φ720mm finished ingot, the crucible dimensions for the three melting processes are Φ570mm, Φ650mm, and Φ720mm respectively. The parameters for the first vacuum consumable melting process are: melting current 12kA~18kA, melting voltage 20V~40V; the parameters for the second vacuum consumable melting process are: melting current 14kA~22kA, melting voltage 20V~40V; and the parameters for the third vacuum consumable melting process are: melting current 14kA~24kA, melting voltage 30V~40V.

7. The method for preparing multi-specification Ti551 titanium alloy ingots according to claim 1, characterized in that, The preparation of a Φ960mm finished ingot includes the following steps: Electrode blocks are arranged, fixed, and welded in two stages to obtain two primary consumable electrodes; the two primary consumable electrodes undergo a first vacuum consumable melting process to obtain two primary ingots. The crucible for the first melting process is Φ820mm, the melting current is 16kA~26kA, and the melting voltage is 30V~40V; after cleaning, flattening, and chamfering the two primary ingots, they are butt-welded in a vacuum consumable arc furnace; the butt-welded ingots undergo a second vacuum consumable melting process, with a crucible of Φ890mm, a melting current of 18kA~28kA, and a melting voltage of 25V~40V; a third vacuum consumable melting process is performed, with a crucible of Φ960mm, a melting current of 20kA~30kA, and a melting voltage of 30V~40V.

8. The method for preparing multi-specification Ti551 titanium alloy ingots according to claim 1, characterized in that, The preparation of a Φ1240mm finished ingot includes the following steps: Electrode blocks are arranged, fixed, and welded in two stages to obtain two primary consumable electrodes; the two primary consumable electrodes undergo a first vacuum consumable melting process to obtain two primary ingots. The crucible for the first melting process is Φ960mm, the melting current is 20kA~30kA, and the melting voltage is 30V~40V; after cleaning, flattening, and chamfering the two primary ingots, they are butt-welded in a vacuum consumable arc furnace; the butt-welded ingots undergo a second vacuum consumable melting process, with a crucible of Φ1170mm, a melting current of 22kA~32kA, and a melting voltage of 30V~40V; a third vacuum consumable melting process is performed, with a crucible of Φ1240mm, a melting current of 24kA~34kA, and a melting voltage of 30V~40V.

9. The method for preparing multi-specification Ti551 titanium alloy ingots according to claim 7 or 8, characterized in that, The welding parameters for the butt welding are as follows: vacuum level ≤7Pa, air leakage rate ≤2.8Pa / min, welding current 3kA~18kA, welding voltage 20V~40V.

10. The method for preparing multi-specification Ti551 titanium alloy ingots according to claim 1 or 2, characterized in that, The density of the pressed electrode block is 3.2 g / cm³. 3 ~3.4g / cm 3 .

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