Method for manufacturing a tc4 alloy

Abstract

The application provides a preparation method of TC4 alloy and relates to the field of metallurgy. The preparation method comprises the following steps: ingredients are prepared according to the Ti-6Al-4V ratio, the ingredients are uniformly mixed, and then the ingredients are pressed into electrode blocks, vacuum plasma welding is performed, and a consumable electrode is obtained; after furnace centering, first, second and third vacuum arc melting is sequentially performed, and a TC4 alloy ingot is obtained after cooling; the first vacuum arc melting and the second vacuum arc melting perform arc starting stage control and stable melting stage control, and the third vacuum arc melting performs arc stage control, stable melting stage control and hot sealing stage control. The preparation method of the TC4 alloy provided by the application controls the stable melting pool morphology in the stable melting stage, reduces the melting pool depth, provides good conditions for the solidification of the ingot, ensures the smooth operation of the melting pool in the melting stage and the hot sealing stage, makes the liquid phase temperature and the composition uniform, reduces the dendrite spacing, and improves the uniformity of the ingot.

Description

TECHNICAL FIELD

[0001] The application relates to the metallurgy field, in particular to a preparation method of TC4 alloy. BACKGROUND

[0002] The nominal composition of TC4 titanium alloy is Ti-6Al-4V. At present, the industrial production generally adopts sponge titanium and aluminum beans as raw materials, and melts ingots through VAR (vacuum consumable arc furnace melting). However, due to the characteristics of high melting point, the titanium alloy requires large melting current, so that the melting speed is large, it is difficult to stabilize the molten pool morphology, the dendrite spacing is large, the molten pool to the edge is poor, the surface quality of the ingot is reduced, the shrinkage hole depth is large and the like, which affect the use performance of the alloy.

[0003] At present, the vacuum consumable melting process of TC4 alloy only sets certain arc current and arc period through experience, and it is still difficult to completely solve the problems of coarse dendrite of alloy solidification structure and large shrinkage hole depth.

[0004] Therefore, in view of the above problems, it is necessary to provide a process for vacuum consumable melting of TC4 alloy. SUMMARY

[0005] The purpose of the application is to provide a preparation method of TC4 alloy to solve the above problems.

[0006] In order to achieve the above purpose, the following technical scheme is adopted in the application:

[0007] A preparation method of TC4 alloy, comprising:

[0008] The raw materials are proportioned according to the Ti-6Al-4V ratio, mixed uniformly, pressed into electrode blocks, vacuum plasma welded to obtain self-consumable electrodes;

[0009] After centering, first vacuum arc melting, second vacuum arc melting and third vacuum arc melting are sequentially carried out, and TC4 alloy ingots are obtained after cooling;

[0010] The first vacuum arc melting and the second vacuum arc melting perform arc starting stage control and stable melting stage control, and the third vacuum arc melting performs arc stage control, stable melting stage control and hot sealing stage control.

[0011] The arc starting stage control includes that the arc current in the arc starting stage is calculated according to formula 1, and the formula 1 is I0=k0D 2 ×2.5×10 -7 ;

[0012] The stable melting stage control includes that the arc current in the stable melting stage is calculated according to formula 2, and the formula 2 is I1=k1I+k2I0.

[0013] The heat-sealing top stage control comprises: the arc stabilizing current of the heat-sealing top stage is calculated according to formula 3, the formula 3 is I2=k3I1;

[0014] In the formula, I0 is the arc stabilizing current of the arc starting stage, A; k0 is a constant, and is 55-65; D is the diameter of the TC4 alloy ingot, mm; I1 is the arc stabilizing current of the stable melting stage, A; k1 is a constant, and is 0.08-0.12; I is the melting current, kA; k2 is a constant, and is 3.48-3.52; I2 is the arc stabilizing current of the heat-sealing top stage, A; k3 is a constant, and is 0.95-0.98.

[0015] Preferably, the diameter D of the TC4 alloy ingot is 650mm-720mm.

[0016] Preferably, the melting current I is 20-35kA.

[0017] Preferably, the cooling mode is furnace cooling.

[0018] Preferably, the cooling time is not less than 7h.

[0019] Preferably, the voltage of the arc starting stage is 35V-45V, and the arc stabilizing period is 5s-10s.

[0020] Preferably, the voltage of the stable melting stage is 30V-40V, and the arc stabilizing period is 10s-20s.

[0021] Preferably, the voltage of the heat-sealing top stage is 15V-20V, and the arc stabilizing period is 10s-20s.

[0022] Preferably, the furnace loading and centering comprises:

[0023] After the crucible is assembled with the bottom pad and loaded into the melting station, the consumable electrode is loaded into the crucible and fixed, the furnace is sealed and vacuumized, the auxiliary electrode is welded with the consumable electrode, and after cooling inspection, the furnace is resealed and vacuumized.

[0024] Preferably, the raw materials comprise sponge titanium, aluminum vanadium intermediate alloy, aluminum beans and titanium dioxide.

[0025] Compared with the prior art, the beneficial effects of the present application include:

[0026] The application provides a preparation method of TC4 alloy, which controls the molten pool morphology stability in the stable melting stage, reduces the molten pool depth, and provides good conditions for ingot solidification; the stable melting stage and the hot sealing stage ensure the smooth operation of the molten pool flow, makes the liquid phase temperature and composition uniform, reduces the dendrite spacing, and improves the uniformity and use performance of the ingot; the stable arc current and the stable arc cycle process are optimized, the shrinkage hole depth is reduced, the cutting head amount is reduced, and the production cost is saved. The stable arc current and the stable arc cycle are reasonably controlled, so that the grain is refined, and the surface quality of the ingot is improved. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as limiting the scope of the application.

[0028] Figure 1 The VAR furnace structure schematic diagram used for the embodiments;

[0029] Figure 2 The stable arc current change curve with smelting time in the VAR smelting TC4 process in the ideal state;

[0030] Figure 3 The shrinkage hole morphology of the embodiments and the comparative examples;

[0031] Figure 4 The primary dendrite spacing (left) and the secondary dendrite spacing (right) of the embodiments and the comparative examples. DETAILED DESCRIPTION

[0032] As used herein the terms "about" and "substantially" mean approximately or nearly, as in "about 90%," "substantially defect-free" or "substantially parallel."

[0033] "Made by" is synonymous with "comprising." The terms "comprising," "including," "having," "containing," or any other similar term are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but can include other elements not expressly listed or inherent to such composition, step, method, article, or apparatus.

[0034] The conjunction "consisting of" excludes any unrecited elements, steps, or components. If used in a claim, this phrase will close the claim to the addition of any element not specified. When this phrase occurs in the body of the specification, it is not a means-plus-function limitation as it occurs only in the introductory part of the specification and only in that sentence.

[0035] When equivalent, concentration, or other value or parameter is expressed in a range, a preferred range, or a series of upper preferred values and lower preferred values, it is to be understood that all ranges formed by any pair of any upper range limit or preferred value and any lower range limit or preferred value, even if the range is not explicitly disclosed, are to be specifically disclosed. For example, when a range "1-5" is disclosed, the described range is to be construed as including the range "1-4", "1-3", "1-2", "1-2 and 4-5", "1-3 and 5", etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include the end values and all integers and fractions within the range.

[0036] In these embodiments, the parts and percentages described are by mass, unless otherwise indicated.

[0037] "Mass parts" refers to a basic unit of measurement representing the mass ratio relationship of multiple components, 1 part can represent any unit mass, such as 1 g, 2.689 g, etc. If we say that the mass parts of component A is a parts, and the mass parts of component B is b parts, it means that the mass ratio of component A to component B is a:b. Alternatively, it means that the mass of component A is aK, and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike mass parts, the sum of the mass parts of all components is not limited to 100 parts.

[0038] "And / or" is used to indicate that one or both of the described situations can occur, for example, A and / or B includes (A and B) and (A or B).

[0039] A preparation method of a TC4 alloy, comprising:

[0040] The raw materials are proportioned according to the Ti-6Al-4V ratio, mixed, and then pressed into an electrode block for vacuum plasma welding to obtain a consumable electrode;

[0041] After centering, first vacuum arc melting, second vacuum arc melting, and third vacuum arc melting are sequentially performed, and the TC4 alloy ingot is obtained after cooling;

[0042] The first vacuum arc melting and the second vacuum arc melting perform arc starting stage control and stable melting stage control, and the third vacuum arc melting performs arc stage control, stable melting stage control, and hot sealing stage control;

[0043] The arc starting stage control includes that the arc stabilizing current in the arc starting stage is calculated according to formula 1, and the formula 1 is I0=k0D 2 ×2.5×10 -7 ;

[0044] The stable melting stage control comprises that the stable arc current of the stable melting stage is calculated according to formula 2, the formula 2 is I1=k1I+k2I0;

[0045] The hot sealing top stage control comprises that the stable arc current of the hot sealing top stage is calculated according to formula 3, the formula 3 is I2=k3I1;

[0046] In the formula, I0 is the stable arc current of the arc striking stage, A; k0 is a constant, and is 55-65; D is the diameter of the TC4 alloy ingot, mm; I1 is the stable arc current of the stable melting stage, A; k1 is a constant, and is 0.08-0.12; I is the melting current, kA; k2 is a constant, and is 3.48-3.52; I2 is the stable arc current of the hot sealing top stage, A; and k3 is a constant, and is 0.95-0.98.

[0047] VAR is melted under the high-temperature action of a direct current arc through a metal consumable electrode and is solidified into an ingot layer by layer from bottom to top in a water-cooled crystallizer. Reasonable stability of the molten pool morphology in the melting process is a key factor affecting the solidification structure of the ingot. After the ingot size and the electrode size are determined, the most important control parameter of the molten pool morphology is the stable arc current and the stable arc period. Over strong stirring causes the molten pool to rotate violently, increases the loss of easily burned elements, increases the depth of the molten pool, and the solidification condition becomes poor; over weak stirring cannot play a good role in uniform molten pool temperature field and liquid phase field, and it is difficult to assist in removing inclusions, resulting in metallurgical defects.

[0048] In an optional embodiment, the diameter D of the TC4 alloy ingot is 650mm-720mm.

[0049] Optionally, the diameter D of the TC4 alloy ingot can be 650mm, 660mm, 670mm, 680mm, 690mm, 700mm, 710mm, 720mm or any value between 650mm and 720mm.

[0050] In an optional embodiment, the melting current I is 20-35kA.

[0051] Optionally, the melting current I can be 20kA, 22kA, 24kA, 26kA, 28kA, 30kA, 32kA, 35kA or any value between 20kA and 35kA.

[0052] In an optional embodiment, the cooling mode is furnace cooling.

[0053] In an optional embodiment, the cooling time is not less than 7h.

[0054] In an optional embodiment, the voltage of the arc striking stage is 35V-45V, and the stable arc period is 5s-10s.

[0055] Optionally, the voltage of the arc striking stage can be 35V, 36V, 37V, 38V, 39V, 40V, 41V, 42V, 43V, 44V, 45V or any value between 35V and 45V, and the arc striking period can be 5s, 6s, 7s, 8s, 9s, 10s or any value between 5s and 10s.

[0056] In an alternative embodiment, the voltage of the stable melting stage is 30V-40V, and the arc striking period is 10s-20s.

[0057] Optionally, the voltage of the stable melting stage can be 30V, 31V, 32V, 33V, 34V, 35V, 36V, 37V, 38V, 39V, 40V or any value between 30V and 40V, and the arc striking period can be 10s, 11s, 12s, 13s, 14s, 15s, 16s, 17s, 18s, 19s, 20s or any value between 10s and 20s.

[0058] In an alternative embodiment, the voltage of the hot sealing top stage is 15V-20V, and the arc striking period is 10s-20s.

[0059] Optionally, the voltage of the hot sealing top stage can be 15V, 16V, 17V, 18V, 19V, 20V or any value between 15V and 20V, and the arc striking period can be 10s, 11s, 12s, 13s, 14s, 15s, 16s, 17s, 18s, 19s, 20s or any value between 10s and 20s.

[0060] In an alternative embodiment, the furnace charging and centering comprises:

[0061] After assembling the crucible with the bottom pad, the crucible is loaded into the melting station, then the consumable electrode is loaded into the crucible for fixation, and the furnace is sealed and vacuumized, the auxiliary electrode is welded with the consumable electrode, and after cooling inspection, the furnace is resealed and vacuumized.

[0062] In an alternative embodiment, the raw materials comprise sponge titanium, aluminum vanadium intermediate alloy, aluminum bean and titanium dioxide.

[0063] The embodiments of the present application will be described in detail below with specific examples, but those skilled in the art will understand that the following examples are only for illustration of the present application and should not be regarded as limiting the scope of the present application. If no specific conditions are specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If no manufacturer of the reagent or instrument is specified, it is a conventional product that can be purchased on the market.

[0064] Example 1

[0065] The embodiment provides a preparation method of TC4 alloy, and specifically comprises the following steps.

[0066] Step 1: national standard titanium sponge, aluminum vanadium intermediate alloy, aluminum beans and titanium dioxide are proportioned according to Ti-6Al-4V, and after being uniformly mixed, the oil press is used to press the mixture into an electrode block, vacuum plasma welding is performed, and a consumable electrode is obtained;

[0067] Step 2: after the 750mm-diameter crucible is assembled with the bottom pad and then loaded into a melting station, the consumable electrode is loaded into the crucible and fixed, the furnace is resealed and vacuumized after the auxiliary electrode is welded to the consumable electrode and cooling inspection, and the auxiliary electrode is welded to the consumable electrode.

[0068] Step 3: three times of vacuum arc furnace melting are performed, wherein the first two times of melting only perform the arc starting stage and the stable melting stage control, and the third time of melting performs the arc starting stage, the stable melting stage and the hot sealing top stage. After melting, a TC4 titanium alloy ingot is obtained, and the cooling time is 9h, and specifically:

[0069] (1) the arc starting stage is used for melting, the current setting value of the arc starting stage is 28kA, the voltage setting value is 42V, the stable arc period is set to 5s, and the stable arc current setting value is determined by the following formula, which is 7.78A.

[0070] I0=k0D 2 ×2.5×10 -7

[0071] In the formula, k0 is a constant, and is 60; D is the diameter of the ingot, and is 720mm.

[0072] (2) the current setting value of the stable melting stage is 27kA, the voltage setting value is 35V, the stable arc period is set to 10s, and the stable arc current setting value is determined by the following formula, which is 29.92A.

[0073] I1=k1I+k2I0

[0074] In the formula, k1 is a constant, and is 0.10; I is the melting current, and is 27kA; k2 is a constant, and is 3.50; I0 is the stable arc current in the arc starting stage, and is 7.78A.

[0075] (3) the current setting value of the hot sealing top stage is 2.5kA, the voltage setting value is 20V, the stable arc period is set to 10s, and the stable arc current setting value is determined by the following formula, which is 28.42A.

[0076] I2=k3I1

[0077] In the formula, k3 is a constant, and is 0.95; I1 is the stable arc current in the stable melting stage, and is 29.92A.

[0078] The VAR furnace used is as shown in Figure 1 Figure 1; the ideal steady arc current curve during VAR smelting of TC4 as a function of smelting time is as shown in Figure 2 Figure 2.

[0079] Embodiment 2

[0080] The embodiment provides a preparation method of TC4 alloy, and specifically comprises the following steps:

[0081] Step 1: national standard sponge titanium, vanadium-aluminum intermediate alloy, aluminum beans and titanium dioxide are proportioned according to the Ti-6Al-4V ratio, mixed and uniformly, and then pressed into an electrode block by an oil press, vacuum plasma welding is performed, and a consumable electrode is obtained;

[0082] Step 2: a 750mm-diameter crucible is assembled with a bottom pad, then loaded into a smelting station, then the consumable electrode is loaded into the crucible and fixed, and the furnace is resealed and vacuumized after welding the auxiliary electrode and the consumable electrode and cooling inspection;

[0083] Step 3: three times of vacuum arc furnace smelting are performed, wherein the first two times of smelting only perform the arc starting stage and the stable smelting stage control, and the third time of smelting performs the arc starting stage, the stable smelting stage and the hot top sealing stage. After smelting, a TC4 titanium alloy ingot is obtained, and the cooling time is 9h, and specifically:

[0084] (1) the arc starting stage is used for smelting, the current set value of the arc starting stage is 28kA, the voltage set value is 42V, the stable arc period is set to 10s, and the stable arc current set value is determined by the following formula, which is 7.78A.

[0085] I0=k0D 2 ×2.5×10 -7

[0086] In the formula, k0 is a constant, which is 60; D is the ingot diameter, which is 720mm.

[0087] (2) the current set value of the stable smelting stage is 27kA, the voltage set value is 35V, the stable arc period is set to 20s, and the stable arc current set value is determined by the following formula, which is 29.92A.

[0088] I1=k1I+k2I0

[0089] In the formula, k1 is a constant, which is 0.10; I is the smelting current, which is 27kA; k2 is a constant, which is 3.50; I0 is the stable arc current in the arc starting stage, which is 7.78A.

[0090] (3) The current setting value of the hot sealing top stage is 2.5kA, the voltage setting value is 20V, the arc stabilizing period is set to 20s, and the arc stabilizing current setting value is determined by the following formula, which is 28.42A.

[0091] I2=k3I1

[0092] In the formula, k3 is a constant, which is 0.95; I1 is the arc stabilizing current of the stable smelting stage, which is 29.92A.

[0093] Example 3

[0094] The embodiment provides a preparation method of TC4 alloy, and specifically comprises the following steps:

[0095] Step 1: The national standard sponge titanium, aluminum vanadium intermediate alloy, aluminum beans and titanium dioxide are dosed according to the Ti-6Al-4V ratio, uniformly mixed, and then pressed into an electrode block by an oil press, vacuum plasma welding is performed, and a consumable electrode is obtained;

[0096] Step 2: Assemble the 670mm diameter crucible with the bottom pad, then load it into the smelting station, then load the consumable electrode into the crucible and fix it, then seal the furnace and vacuumize, then weld the auxiliary electrode with the consumable electrode, then reseal the furnace and vacuumize after cooling and inspection;

[0097] Step 3: Perform three times of vacuum arc furnace smelting, wherein the first two times of smelting only perform the arc starting stage and the stable smelting stage control, and the third time of smelting performs the arc starting stage, the stable smelting stage and the whole process of the hot sealing top stage. After smelting, a TC4 titanium alloy ingot is obtained, and the cooling time is 8h, which is specifically:

[0098] (1) The arc starting smelting is performed, the current setting value of the arc starting stage is 26kA, the voltage setting value is 37V, the arc stabilizing period is set to 7s, and the arc stabilizing current setting value is determined by the following formula, which is 5.81A.

[0099] I0=k0D 2 ×2.5×10 -7

[0100] In the formula, k0 is a constant, which is 55; D is the diameter of the ingot, which is 650mm.

[0101] (2) The current setting value of the stable smelting stage is 25kA, the voltage setting value is 31V, the arc stabilizing period is set to 15s, and the arc stabilizing current setting value is determined by the following formula, which is 22.22A.

[0102] I1=k1I+k2I0

[0103] In the formula, k1 is a constant, which is 0.08; I is the smelting current, which is 25kA; k2 is a constant, which is 3.48; I0 is the arc stabilizing current of the arc starting stage, which is 5.81A.

[0104] (3) The current setting value of the hot sealing top stage is 2.5 kA, the voltage setting value is 15 V, the arc stabilizing period is set to 15 s, and the arc stabilizing current setting value is determined by the following formula, which is 21.78 A.

[0105] I2=k3I1

[0106] In the formula, k3 is a constant, which is 0.98; I1 is the arc stabilizing current of the stable melting stage, which is 22.22 A.

[0107] Comparative Example 1

[0108] The difference between this comparative example 1 and example 1 is that the arc stabilizing current setting value is 30 A, and the arc stabilizing period setting value is 60 s.

[0109] Comparative Example 2

[0110] The difference between this comparative example 2 and example 1 is that the melting only performs the arc stabilizing stirring control of the arc starting stage, and the arc stabilizing current setting value of the remaining two stages is 30 A, and the arc stabilizing period setting value is 60 s.

[0111] Comparative Example 3

[0112] The difference between this comparative example 3 and example 1 is that the melting only performs the arc stabilizing stirring control of the stable melting stage, and the arc stabilizing current setting value of the remaining two stages is 30 A, and the arc stabilizing period setting value is 60 s.

[0113] Comparative Example 4

[0114] The difference between this comparative example 4 and example 1 is that the melting only performs the arc stabilizing stirring control of the hot sealing top stage, and the arc stabilizing current setting value of the remaining two stages is 30 A, and the arc stabilizing period setting value is 60 s.

[0115] The shrinkage cavity depth, the maximum value of the molten pool depth in the stable melting stage, and the dendrite arm spacing at the ingot head, ingot core and ingot tail of each example and comparative example are measured, and the examples are all optimal, as shown in Tables 1 and 2.

[0116] Table 1 Shrinkage cavity depth and maximum value of molten pool depth in stable melting stage of each example and comparative example

[0117] Name Depth of crater (m) Depth of molten pool (m) Example 1 0.357 1.655 Example 2 0.367 1.731 Example 3 0.197 1.398 Comparative Example 1 0.415 1.851 Comparative Example 2 0.414 1.893 Comparative Example 3 0.413 1.752 Comparative Example 4 0.383 1.893

[0118] The shrinkage cavity morphology of each example and comparative example is shown in Figure 3 .

[0119] Table 2 Dendrite arm spacing at ingot head, ingot core and ingot tail of each example and comparative example

[0120]

[0121] The primary dendrite spacing (left) and the secondary dendrite spacing (right) of each embodiment and the comparative example are shown in Table 1. Figure 4

[0122] The shrinkage depth and the maximum molten pool depth in the stable melting stage are listed in Table 1. The smaller the shrinkage depth, the less the ingot head cutting amount, and the lower the material loss. It can be seen from the comparison that the shrinkage depth of the embodiments is about 10.9% smaller than that of the comparative example on average. The smaller the maximum molten pool depth, the better the solidification condition. It can be seen from the comparison that the maximum molten pool depth of the embodiments is about 8.3% smaller than that of the comparative example on average. The optimization effect of the embodiments is obvious.

[0123] The dendrite spacing at the ingot head, the ingot core and the ingot tail is listed in Table 2. The smaller the spacing, the better the uniformity of the ingot, and the higher the material performance. It can be seen from the comparison that the dendrite spacing at the ingot head of the embodiments is about 12.4% smaller than that of the comparative example on average, about 3.4% smaller at the ingot core, and about 4.0% smaller at the ingot tail. The optimization effect of the embodiments is obvious.

[0124] Among them, the ingot size of Example 3 is the smallest among all the embodiments and the comparative example, and the values of the melting parameters are smaller than those of other cases, so the melting rate is smaller, and the maximum molten pool depth at the end of the stable melting stage is smaller. It can be seen that the shrinkage depth value obtained under the same feeding process is smaller. According to the solidification theory, the smaller the size of the ingot, the greater the cooling rate of the liquid phase at the center of the molten pool, and the smaller the dendrite spacing at the solidification front. However, compared with the average values of Example 1 and Example 2, the shrinkage depth of Example 3 is reduced by about 45.5%, the maximum molten pool depth is reduced by about 17.4%, and the dendrite spacing at the ingot head, the ingot core and the ingot tail is reduced by about 8.53%, 8.85% and 29.3% respectively, that is, obvious optimization effect can still be achieved under different ingot sizes.

[0125] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

[0126] In addition, those skilled in the art can understand that although some embodiments herein include certain features included in other embodiments rather than other features, the combination of features of different embodiments means to be within the scope of the present application and form different embodiments. For example, in the above claims, any one of the claimed embodiments can be used in any combination. The information disclosed in the BACKGROUND section is only intended to deepen the understanding of the overall background of the present application, and should not be regarded as acknowledging or implying in any form that the information constitutes prior art known to those skilled in the art.​

Claims

1. A method for preparing a TC4 alloy, characterized in that, The application relates to a TC4 alloy ingot preparation method. The first vacuum arc melting, the second vacuum arc melting and the third vacuum arc melting are sequentially carried out after the furnace centering, and the TC4 alloy ingot is obtained through cooling; The first vacuum arc melting and the second vacuum arc melting perform arc starting stage control and stable melting stage control, and the third vacuum arc melting performs arc starting stage control, stable melting stage control and hot sealing stage control; The stable melting stage control comprises that the stable arc current of the stable melting stage is calculated according to formula 2, and the formula 2 is I1=k1I+k2I0; The arc striking phase control comprises: the arc striking phase stable arc current is calculated according to formula 1, the formula 1 is I0=k0D 2 ×2.5×10 -7 ; The hot sealing stage control comprises that the stable arc current of the hot sealing stage is calculated according to formula 3, and the formula 3 is I2=k3I1; In the formula, I0 is the stable arc current of the arc starting stage, A; k0 is a constant, and is 55-65; D is the diameter of the TC4 alloy ingot, mm; I1 is the stable arc current of the stable melting stage, A; k1 is a constant, and is 0.08-0.12; I is the melting current, kA; k2 is a constant, and is 3.48-3.52; I2 is the stable arc current of the hot sealing stage, A; and k3 is a constant, and is 0.95-0.

98. The diameter D of the TC4 alloy ingot is 650mm-720mm.

2. The method of making a TC4 alloy of claim 1, wherein, The melting current I is 20-35kA.

3. The method of claim 1, wherein the TC4 alloy is prepared by the steps of: The cooling mode is furnace cooling.

4. The method of claim 1, wherein the TC4 alloy is prepared by the steps of: The cooling time is not less than 7h.

5. The method of claim 4, wherein the TC4 alloy is prepared by the steps of: The voltage of the arc starting stage is 35V-45V, and the stable arc period is 5s-10s.

6. The method of claim 1, wherein the TC4 alloy is prepared by the steps of: The voltage of the stable melting stage is 30V-40V, and the stable arc period is 10s-20s.

7. The method of claim 1, wherein the TC4 alloy is prepared by the steps of: The voltage of the hot sealing stage is 15V-20V, and the stable arc period is 10s-20s.

8. The method of producing a TC4 alloy according to claim 1, wherein The furnace centering comprises the following steps:

9. The method of making a TC4 alloy of claim 1, wherein, After the crucible and the bottom pad are assembled and loaded into a melting station, the consumable electrode is loaded into the crucible and fixed, vacuum is extracted after the furnace is sealed, the auxiliary electrode is welded with the consumable electrode, and the furnace is resealed and vacuum-extracted after cooling and inspection. The raw materials comprise sponge titanium, aluminum-vanadium intermediate alloy, aluminum beans and titanium dioxide.

10. The method for preparing the TC4 alloy according to any one of claims 1-9, characterized in that, ​

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