Method for controlling TC4 titanium alloy component segregation based on relative coefficient batching method

Abstract

The invention relates to a method for controlling composition segregation of a TC4 titanium alloy based on a relative coefficient batching method. The method comprises the steps that S1, sponge titanium, an aluminum-vanadium intermediate alloy and aluminum particles are selected as raw materials for smelting the TC4 titanium alloy; s2, according to the initial electrode length, a relative coefficient burdening method is adopted for burdening, and an electrode block is formed through pressing; s3, the electrode blocks are assembled and welded into initial electrodes in sequence; and S4, the initial electrode is subjected to VAR smelting, and the TC4 titanium alloy cast ingot is obtained. According to the process for smelting the TC4 titanium alloy based on the VAR, aiming at the segregation problem of the Al element and the V element of the TC4 titanium alloy at different positions of the cast ingot, the electrode block is prepared by adopting a relative coefficient batching method, the composition segregation degree of the TC4 titanium alloy cast ingot is effectively reduced, and the method can be used for smelting the TC4 titanium alloy in different specifications of VAR furnace profiles and has relatively high practicability and generalization performance.

Description

Technical Field

[0001] The invention relates to the technical field of vanadium and titanium, and in particular to a method for controlling the segregation of components of a TC4 titanium alloy based on a relative coefficient batching method. Background Art

[0002] Vacuum consumable melting (VAR) is the main method for producing titanium alloys. During the consumable melting process, the ingot is continuously solidified and increased from bottom to top in the crystallizer. The cooling conditions, molten pool shape and depth are not constant. Therefore, improper process control will cause various ingot defects during the melting process. The uneven chemical composition of each part of the ingot is called segregation, which is one of the ingot quality defects. This uneven composition will directly affect the performance of the material.

[0003] Reasonable batching method is one of the many factors that affect the degree of ingot segregation. At present, industrial production mainly adopts mixing method, alloy package method, sequential distribution method and other methods to prepare electrode blocks, but the smelted titanium alloy ingots still have a certain degree of component segregation. Therefore, it is of vital significance to develop a batching method that can control the degree of ingot segregation. Summary of the invention

[0004] In view of the above problems, the object of the present invention is to provide a method for controlling the segregation of TC4 titanium alloy components based on the relative coefficient batching method. According to the segregation characteristics of Al and V elements in the TC4 ingot, the relative coefficient batching method is adopted to adjust the distribution of Al and V elements in different parts of the ingot, thereby achieving the purpose of controlling the segregation of the TC4 ingot components.

[0005] The technical solution adopted by the present invention is as follows:

[0006] The present invention proposes a method for controlling the segregation of TC4 titanium alloy components based on the relative coefficient batching method, which specifically comprises the following steps:

[0007] S1. Use titanium sponge, aluminum-vanadium master alloy and aluminum particles as raw materials for smelting TC4 titanium alloy;

[0008] S2. According to the initial electrode length, the relative coefficient batching method is used to batch the materials and press them into electrode blocks;

[0009] S3, welding the electrode blocks in sequence to form initial electrodes;

[0010] S4. The initial electrode is smelted by VAR to obtain TC4 titanium alloy ingot.

[0011] Furthermore, in step S1, the particle size of the titanium sponge is 0.83-12.70 mm; the aluminum-vanadium master alloy is AlV55 or AlV65, with a particle size of 1.0-6.0 mm; the purity of the aluminum particles is ≥99.70%, with a particle size of 5.0-10.0 mm.

[0012] Furthermore, in step S2, the length of the initial electrode is L, and the relative coefficient = ingredient composition / target composition.

[0013] Furthermore, in step S2, the scheme of using the relative coefficient batching method to batch is as follows:

[0014] 1 / 3L area of ​​the electrode block head: the relative coefficient of Al is 1.018-1.030, and the relative coefficient of V is 1.007-1.027;

[0015] 1 / 3L area in the middle of the electrode block: the relative coefficient of Al is 1.000-1.012, and the relative coefficient of V is 1.002-1.025;

[0016] 1 / 3L area at the bottom of the electrode block: the relative coefficient of Al is 1.002-1.012, and the relative coefficient of V is 1.002-1.025;

[0017] Furthermore, in step S3, when the initial electrodes are welded, the head, middle and bottom electrode blocks prepared by the relative coefficient batching method are welded in sequence.

[0018] Furthermore, in step S4, the smelting parameters are: melting arc stabilizing alternating current 5.5-8.8A, melting voltage 25-30V, and melting current 4000-6000A.

[0019] Furthermore, in the chemical composition of the TC4 titanium alloy ingot, Al element ≤ 0.20%, V element ≤ 0.15%.

[0020] Furthermore, the nominal composition of the TC4 titanium alloy ingot is: Ti-5.50~6.75Al-3.50~4.50V.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention is based on the process of VAR smelting TC4 titanium alloy, aims at the segregation problem of Al element and V element in different positions of the TC4 titanium alloy ingot, adopts the relative coefficient batching method to prepare the electrode block, and effectively reduces the degree of component segregation of the TC4 titanium alloy ingot. The method of the present invention can be used for smelting TC4 titanium alloy in VAR furnaces of different specifications, and has strong practicality and popularization. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic flow chart of a method for controlling component segregation of TC4 titanium alloy based on a relative coefficient batching method proposed in the present invention;

[0024] Figure 2 It is a schematic diagram of the area where the electrode block is located in the present invention. DETAILED DESCRIPTION

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] See attached Figure 1 The present invention proposes a method for controlling the segregation of TC4 titanium alloy components based on the relative coefficient batching method, which specifically includes the following steps:

[0027] S1. Use sponge titanium, aluminum-vanadium master alloy and aluminum particles as raw materials for smelting TC4 titanium alloy; the sponge titanium specification is small particle size or fine particle size, the particle size of sponge titanium is 0.83-12.70 mm; the aluminum-vanadium master alloy is AlV55 or AlV65, the particle size is 1.0-6.0 mm; the purity of aluminum particles is ≥99.70%, and the particle size is 5.0-10.0 mm.

[0028] S2. According to the initial electrode length, the relative coefficient batching method is used to batch the materials and press them into electrode blocks; the length and diameter of the initial electrode are defined as L, and the relative coefficient is defined as: relative coefficient = batching composition / target composition.

[0029] The scheme for batching using the relative coefficient batching method is shown in the following table:

[0030]

[0031] S3, welding the electrode blocks into initial electrodes in sequence; when welding the initial electrodes, welding is performed in sequence according to the head, middle and bottom electrode blocks prepared in the relative coefficient batching method.

[0032] S4. The initial electrode is subjected to VAR smelting to obtain a TC4 titanium alloy ingot; wherein the smelting parameters are: smelting arc stabilizing alternating current 5.5-8.8A, smelting voltage 25-30V, and smelting current 4000-6000A.

[0033] The chemical composition of the prepared TC4 titanium alloy ingot is that the Al element is ≤0.20%, and the V element is ≤0.15%.

[0034] The nominal composition of TC4 titanium alloy ingot is: Ti-5.50~6.75Al-3.50~4.50V.

[0035] The method is further described below by means of specific embodiments:

[0036] Embodiment 1

[0037] A method for controlling the segregation of TC4 titanium alloy components based on the relative coefficient batching method, the specific implementation steps are as follows:

[0038] S1. The raw materials for smelting TC4 titanium alloy are titanium sponge, aluminum-vanadium master alloy and aluminum particles. The requirements for various materials are as follows:

[0039] Titanium sponge: The composition index meets the requirements of GB / T 2524-2019, particle size: 0.5-5.0 mm;

[0040] Aluminum particles: purity ≥99.70%, particle size 5.0~10.0mm;

[0041] Aluminum-vanadium master alloy: AlV55 grade, composition index meets YS / T 579-2014, particle size: 1.0~6.0mm;

[0042] S2. According to the initial electrode length, the relative coefficient batching method is used to batch the materials and press them into electrode blocks. The target composition of the TC4 ingot prepared in this embodiment and the actual batching composition of the electrode blocks in each region are as follows:

[0043]

[0044] S3. Weld the electrode blocks in the order of head, middle and bottom to obtain an initial electrode.

[0045] S4, the initial electrode is subjected to VAR smelting to obtain TC4 titanium alloy ingot. The smelting process parameters are selected as arc-stabilizing alternating current 5.5-6.5A, smelting voltage 26-28V, and smelting current 4800-5800A.

[0046] The TC4 titanium alloy ingot obtained in this embodiment is a small-sized ingot, weighing 120 kg, and the main components are Ti-5.50-6.75Al-3.50-4.50V. The extreme difference of the components: the extreme difference of Al element is 0.11%, and the extreme difference of V element is 0.12%.

[0047] Compared with the original process, the effect of improving the extreme difference level of ingredients is shown in the following table:

[0048]

[0049]

[0050] Embodiment 2:

[0051] A method for controlling the component segregation of TC4 titanium alloy based on the relative coefficient batching method, the specific implementation steps are as follows:

[0052] S1. The raw materials for smelting TC4 titanium alloy are titanium sponge, aluminum-vanadium master alloy and aluminum particles. The requirements for various materials are as follows:

[0053] Titanium sponge: The composition index meets the requirements of GB / T 2524-2019, particle size: 0.5-5.0 mm;

[0054] Aluminum particles: purity ≥99.70%, particle size 5.0~10.0mm;

[0055] Aluminum-vanadium master alloy: AlV55 grade, composition index meets YS / T 579-2014, particle size: 1.0~6.0mm;

[0056] S2. According to the initial electrode length, the relative coefficient batching method is used to batch the materials and press them into electrode blocks. The target composition of the TC4 ingot prepared in this embodiment and the actual batching composition of the electrode blocks in each region are as follows:

[0057]

[0058] S3. Weld the electrode blocks in the order of head, middle and bottom to obtain an initial electrode.

[0059] S4, the initial electrode is subjected to VAR smelting to obtain TC4 titanium alloy ingot. The smelting process parameters are selected as arc-stabilizing alternating current 5.5-6.5A, smelting voltage 26-28V, and smelting current 4800-5800A.

[0060] The TC4 titanium alloy ingot obtained in this embodiment is a small-sized ingot, weighing 150 kg, and the main components meet the requirements of Ti-5.50-6.75Al-3.50-4.50V. The extreme difference of the components: the extreme difference of Al element is 0.13%, and the extreme difference of V element is 0.09%.

[0061] Compared with the original process, the effect of improving the extreme difference level of ingredients is shown in the following table:

[0062]

[0063]

[0064] Embodiment three:

[0065] A method for controlling the component segregation of TC4 titanium alloy based on the relative coefficient batching method, the specific implementation steps are as follows:

[0066] S1. The raw materials for smelting TC4 titanium alloy are titanium sponge, aluminum-vanadium master alloy and aluminum particles. The requirements for various materials are as follows:

[0067] Titanium sponge: The composition index meets the requirements of GB / T 2524-2019, particle size: 0.5-5.0 mm;

[0068] Aluminum particles: purity ≥99.70%, particle size 5.0~10.0mm;

[0069] Aluminum-vanadium master alloy: AlV55 grade, composition index meets YS / T 579-2014, particle size: 1.0~6.0mm;

[0070] S2. According to the initial electrode length, the relative coefficient batching method is used to batch the materials and press them into electrode blocks. The target composition of the TC4 ingot prepared in this embodiment and the actual batching composition of the electrode blocks in each region are as follows:

[0071]

[0072] S3. Weld the electrode blocks in the order of head, middle and bottom to obtain an initial electrode.

[0073] S4, the initial electrode is subjected to VAR smelting to obtain TC4 titanium alloy ingot. The smelting process parameters are selected as arc-stabilizing alternating current 5.5-6.5A, smelting voltage 26-28V, and smelting current 4800-5800A.

[0074] The TC4 titanium alloy ingot obtained in this embodiment is a small-sized ingot, weighing 200 kg, and the main components meet the requirements of Ti-5.50-6.75Al-3.50-4.50V. The extreme difference of the components: the extreme difference of Al element is 0.16%, and the extreme difference of V element is 0.11%.

[0075] Compared with the original process, the effect of improving the extreme difference level of ingredients is shown in the following table:

[0076]

[0077]

[0078] During the vacuum consumable smelting process, the ingot is continuously solidified and increased in height from bottom to top in the crystallizer. The cooling conditions, molten pool shape and depth are not constant at different stages such as the arc starting period, smelting period and shrinkage feeding period. The alloying elements in titanium alloys have different degrees of loss at different stages of smelting due to their differences in physical and chemical properties. When the molten pool solidifies, segregation is formed in different areas of the ingot accordingly. Therefore, the method of the present invention is proposed to control the degree of segregation of the ingot by adjusting the initial electrode ingredients to follow the loss law of the alloying elements.

[0079] Matters not described in detail in the present invention are all known technologies.

[0080] The embodiments described above are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for controlling the segregation of TC4 titanium alloy components based on the relative coefficient batching method, characterized in that: The method comprises the following steps: S1. Use titanium sponge, aluminum-vanadium master alloy and aluminum particles as raw materials for smelting TC4 titanium alloy; S2. According to the initial electrode length, the relative coefficient batching method is used to batch the materials and press them into electrode blocks; S3, welding the electrode blocks in sequence to form initial electrodes; S4. The initial electrode is subjected to VAR smelting to obtain a TC4 titanium alloy ingot.

2. The method for controlling the component segregation of TC4 titanium alloy based on the relative coefficient batching method according to claim 1, characterized in that: In the step S1, the particle size of the titanium sponge is 0.83-12.70 mm; the aluminum-vanadium master alloy is AlV55 or AlV65, with a particle size of 1.0-6.0 mm; the purity of the aluminum particles is ≥99.70%, with a particle size of 5.0-10.0 mm.

3. The method for controlling the component segregation of TC4 titanium alloy based on the relative coefficient batching method according to claim 1, characterized in that: In the step S2, the length of the initial electrode is L, and the relative coefficient = batching component / target component.

4. The method for controlling the component segregation of TC4 titanium alloy based on the relative coefficient batching method according to claim 3 is characterized in that: In step S2, the scheme of using the relative coefficient batching method to batch is as follows: 1 / 3L area of ​​the electrode block head: the relative coefficient of Al is 1.018-1.030, and the relative coefficient of V is 1.007-1.027; 1 / 3L area in the middle of the electrode block: the relative coefficient of Al is 1.000-1.012, and the relative coefficient of V is 1.002-1.025; In the bottom 1 / 3L area of ​​the electrode block, the relative coefficient of Al is 1.002-1.012, and the relative coefficient of V is 1.002-1.

025.

5. The method for controlling the component segregation of TC4 titanium alloy based on the relative coefficient batching method according to claim 4, characterized in that: In the step S3, when the initial electrodes are welded together, the head, middle and bottom electrode blocks prepared by the relative coefficient batching method are welded together in sequence.

6. The method for controlling the component segregation of TC4 titanium alloy based on the relative coefficient batching method according to claim 1, characterized in that: In the step S4, the smelting parameters are: arc stabilizing alternating current 5.5-8.8A, smelting voltage 25-30V, and smelting current 4000-6000A.

7. The method for controlling the component segregation of TC4 titanium alloy based on the relative coefficient batching method according to claim 1, characterized in that: In the chemical composition of the TC4 titanium alloy ingot, Al element is ≤0.20%, and V element is ≤0.15%.

8. The method for controlling the component segregation of TC4 titanium alloy based on the relative coefficient batching method according to claim 1, characterized in that: The nominal composition of the TC4 titanium alloy ingot is: Ti-5.50-6.75Al-3.50-4.50V.

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