CN112126805B - Preparation method of industrial pure titanium or TC4 titanium alloy ingot with weight of 10 t-15 t - Google Patents

Abstract

The invention provides a preparation method of an industrial pure titanium or titanium alloy ingot with the weight of 10 t-15 t, which is suitable for preparing the industrial pure titanium or TC4 titanium alloy ingot with the diameter range of phi 960 mm-phi 1150mm, and fills the technical blank in the field of industrial pure titanium or TC4 titanium alloy ingot products of more than 10t in China. According to the invention, through carrying out multiple times of vacuum melting on the consumable electrode and reasonably controlling the melting process parameters, the ingot composition and structure uniformity are improved, the impurity content is reduced, and the industrial pure titanium or titanium alloy ingot with high uniformity, high purity and high consistency and weight of 10 t-15 t is obtained.

Description

Preparation method of industrial pure titanium or TC4 titanium alloy ingot with weight of 10 t-15 t

Technical Field

The invention belongs to the technical field of nonferrous metal processing, and particularly relates to a preparation method of an industrial pure titanium or TC4 titanium alloy ingot with the weight of 10 t-15 t.

Background

The titanium alloy has excellent mechanical, chemical and physical properties, has incomparable superiority compared with stainless steel, aluminum alloy or copper alloy and the like, and has wide application in the fields of ships, aviation and the like. For example: the American sea military titanium alloy pipe replaces a copper-nickel alloy pipe for a heat exchanger, and a cast titanium alloy pump replaces a sea water pump on a naval vessel deck; russian not only uses a large amount of titanium materials on parts such as condensers and heat exchangers of nuclear submarines and conventional submarines, but also develops all-titanium nuclear submarines, and titanium used for a single boat exceeds 3000 tons; titanium materials are also used in various marine water jet propulsion units in japan.

Because the welding performance of the titanium alloy is not high, the large-scale forging welding pretreatment process is complex, the engineering welding degree is low, and the large single-weight titanium material provides necessary guarantee for improving the overall performance of the material forging. In order to obtain a large single weight titanium material with the structure performance meeting the requirements, an oversized ingot with the components uniformity, impurity content and the like meeting the requirements is obtained. However, at present, the weight of a single titanium alloy ingot with a high alloying degree in China, such as TC18, TC21 and the like, cannot exceed 8 tons at most. The main reason is that as the ingot shape of the ingot increases, the segregation degree of alloy elements correspondingly increases, the uniformity of components becomes poor, and finally the structure and the performance of the forging cannot meet the use requirements. Therefore, how to break through the ingot casting smelting technology of more than 10 tons and obtain the ultra-large-specification industrial pure titanium or titanium alloy ingot with high uniformity, high purity and high consistency provides great challenges for the smelting process and the process control of the industrial pure titanium or titanium alloy ingot.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a preparation method of industrial pure titanium or TC4 titanium alloy ingots with the weight of 10 t-15 t, fills the blank in the field of preparation of integral forgings and ingots of titanium and titanium alloys above 8t in China, and provides necessary guarantee for improving the integral performance of high-end equipment.

Except for special description, the parts are parts by weight, and the percentages are mass percentages.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a preparation method of industrial pure titanium or TC4 titanium alloy ingots with the weight of 10 t-15 t is characterized by comprising the following steps:

step (1): preparing materials according to the proportioning requirement of industrial pure titanium or TC4 titanium alloy in the national standard GB/T3620.1, uniformly mixing, pressing the uniformly mixed raw materials in an integral electrode press to form an integral electrode with the single weight of 5T-7.5T, and preparing two groups in total;

step (2): respectively carrying out first vacuum consumable arc melting on the two groups of integral electrodes obtained in the step (1) to obtain a primary ingot, wherein the vacuum degree is less than or equal to 5.0Pa, the melting current is 25-38 kA, the melting voltage is 28-40V, and the cooling time is more than or equal to 5 hours;

and (3): carrying out furnace welding on the two groups of primary ingots obtained in the step (2), wherein the welding vacuum degree is less than or equal to 5.0Pa, the welding current is 6-30 kA, and the welding voltage is 22-35V;

and (4): carrying out secondary vacuum consumable melting on the ingot with the unit weight of 10 t-15 t obtained in the step (3), wherein the vacuum degree is less than or equal to 3.0Pa, the melting current is 32-38 kA, the melting voltage is 31-40V, and the cooling time after melting is not less than 7 hours;

and (5): and (4) smelting the ingot with the unit weight of 10 t-15 t by using a vacuum arc furnace, and carrying out surface turning machining to obtain the industrial pure titanium or TC4 titanium alloy finished product ingot.

Further, the diameter of the whole electrode in the step (1) is 650 mm.

Further, the diameter of the crystallizer of the melting crucible for the first vacuum consumable arc melting in the step (2) is phi 833 mm.

Further, the furnace welding in the step (3) is furnace welding in a crucible crystallizer with the diameter phi 960 mm.

Further, the diameter of the crystallizer of the melting crucible for the second vacuum consumable melting in the step (4) is phi 960 mm.

Further, after the second vacuum consumable melting in the step (4), the third vacuum consumable melting is carried out, the vacuum degree of the third vacuum consumable melting is less than or equal to 3.0Pa, the melting current is 32-38 kA, the melting voltage is 31-40V, and the cooling time after the melting is not less than 7 hours.

Further, the diameter of the crystallizer of the melting crucible for the third vacuum consumable melting is phi 1150 mm.

Further, feeding is started when the consumable electrode is melted with the residual weight of 300-400 kg in the last melting (second or third vacuum consumable melting). When the second vacuum consumable melting is the last melting, feeding is started when the consumable electrode melting is carried out for 300-400 kg of residual weight; and when the third vacuum consumable melting is the last melting, feeding is started when the consumable electrode melts the residual weight of 300-400 kg.

Further, the industrial pure titanium is required by GB/T3620.1 standard, and the raw materials comprise: titanium sponge, Ti-32Fe intermediate alloy, TiO₂Powder, total component weight 100%; the TC4 titanium alloy meets the requirements of GB/T3620.1 standard, and the raw materials comprise: titanium sponge, Al-V alloy, Ti-32Fe intermediate alloy and TiO2 powder, wherein the total component weight is 100%.

A preparation method of industrial pure titanium or TC4 titanium alloy ingots with the weight of 10 t-15 t is characterized by comprising the following steps:

step (1): the method comprises the steps of proportioning and uniformly mixing industrial pure titanium or TC4 titanium alloy according to the proportioning requirement of national standard GB/T3620.1, pressing the uniformly mixed raw materials into an integral electrode with the single weight of 5T-7.5T in an integral electrode press, wherein the diameter of the integral electrode is 650mm, and the density is 3.2-3.4 g/cm³The length is 4.5-6.5 m, and two groups are prepared in total;

step (2): respectively carrying out first vacuum consumable arc melting on the two groups of integral electrodes obtained in the step (1) to obtain a primary ingot, wherein the vacuum degree is less than or equal to 5.0Pa, the melting current is 25-38 kA, the melting voltage is 28-40V, the diameter of a melting crucible crystallizer is phi 833mm, and the cooling time is more than or equal to 5 hours;

and (3): carrying out furnace welding on the two groups of primary ingots obtained in the step (2) in a crucible crystallizer with the diameter phi of 960mm, wherein the welding vacuum degree is less than or equal to 5.0Pa, the welding current is 6-30 kA, and the welding voltage is 22-35V;

and (4): carrying out secondary vacuum consumable melting on the ingot with the unit weight of 10 t-15 t obtained in the step (3), wherein the vacuum degree is less than or equal to 3.0Pa, the melting current is 32-38 kA, the melting voltage is 31-40V, the diameter of a melting crucible crystallizer is phi 960mm, and the cooling time after melting is not less than 7 hours;

and (5): carrying out third vacuum consumable melting on the ingot with the unit weight of 10 t-15 t obtained in the step (4), wherein the vacuum degree is less than or equal to 3.0Pa, the melting current is 32-38 kA, the melting voltage is 31-40V, the diameter of a melting crucible crystallizer is phi 1150mm, feeding is started when the consumable electrode melts the residual weight of 300-400 kg, the melting current is gradually reduced, and the cooling time after melting is not less than 7 hours;

and (6): and (4) smelting the ingot with the unit weight of 10 t-15 t by using the vacuum arc furnace obtained in the step (5), and carrying out surface turning machining to obtain the industrial pure titanium or TC4 titanium alloy finished product ingot.

Has the advantages that:

the invention provides a preparation method of an industrial pure titanium or titanium alloy ingot with the weight of 10 t-15 t, which is suitable for preparing the industrial pure titanium or TC4 titanium alloy ingot with the diameter range of phi 960 mm-phi 1150mm, and fills the technical blank in the field of industrial pure titanium or TC4 titanium alloy ingot products of more than 10t in China. According to the invention, through carrying out multiple times of vacuum melting on the consumable electrode and reasonably controlling the melting process parameters, the ingot composition and structure uniformity are improved, the impurity content is reduced, and the industrial pure titanium or titanium alloy ingot with high uniformity, high purity and high consistency and weight of 10 t-15 t is obtained.

Drawings

FIG. 1 is a schematic view showing a longitudinal 3-point sampling position in examples 1 and 2;

FIG. 2 is a schematic diagram of the lateral 9-point sampling positions in examples 3 and 4.

Detailed Description

The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.

Example 1:

a preparation method of titanium and titanium alloy ingots with the weight of 10 t-15 t comprises the following steps:

step (1): according to the proportioning requirement of industrial pure titanium in the national standard GB/T3620.1, sponge titanium, Ti-32Fe intermediate alloy and TiO₂Powder with total weight of 10t and total component weight of 100 percent is uniformly mixed, and the uniformly mixed raw materials are pressed into a single 5t integral electrode in an integral electrode press machine, and the integral electrodeHas a diameter of 650mm and a density of 3.2g/cm³Length 4.7m, 2 in total;

step (2): respectively carrying out primary vacuum consumable arc melting on the integral electrode obtained in the step (1), wherein the vacuum degree is less than or equal to 5.0Pa, the melting current is 25-32 kA, the melting voltage is 28-36V, the diameter phi 833mm of a crystallizer of a melting crucible is reduced, and the cooling time is more than or equal to 5 hours;

and (3): carrying out furnace welding on the 2 primary ingots obtained in the step (2) in a crucible crystallizer with the diameter phi of 960mm, wherein the welding vacuum degree is less than or equal to 5.0Pa, the welding current is 6-16 kA, and the welding voltage is 22-30V;

and (4): and (3) carrying out secondary vacuum consumable melting on the primary ingot with the unit weight of 10t obtained in the step (3), wherein the vacuum degree is less than or equal to 3.0Pa, the melting current is 32-36 kA, the melting voltage is 31-40V, the diameter of a melting crucible crystallizer is phi 960mm, feeding is started when the consumable electrode melts the residual weight of 300kg, the melting current is gradually reduced, and the cooling time after melting is not less than 7 hours.

And (5): and (4) smelting the ingot with the single weight of 10t and the diameter of phi 960mm obtained in the step (4) through a vacuum arc furnace, and carrying out surface turning machine processing to obtain the industrial pure titanium finished product ingot.

The chemical components at 3 points in the longitudinal direction of the industrial pure titanium ingot of example 1 were measured by the above-mentioned detection method specified by the national standard, and the results are shown in table 1.

TABLE 1 longitudinally 3-point chemical composition sampling test results of commercial pure titanium ingot of example 1

Sampling site	O	Fe	C	N	H
						Upper part	0.08	0.11	0.006	0.008	0.0013
Middle part	0.09	0.08	0.007	0.009	0.0010
						Lower part	0.07	0.09	0.010	0.011	0.0012
Standard requirements	≤0.15	≤0.15	≤0.1	≤0.03	≤0.015

Example 2:

a preparation method of titanium and titanium alloy ingots with the weight of 10 t-15 t comprises the following steps:

step (1):according to the proportioning requirement of TC4 titanium alloy in the national standard GB/T3620.1, sponge titanium, Ti-32Fe intermediate alloy, Al-V intermediate alloy and TiO₂Powder with total weight of 10t and total component weight of 100 percent is uniformly mixed, the uniformly mixed raw materials are pressed into a single 5t integral electrode in an integral electrode press, the diameter of the integral electrode is 650mm, and the density is 3.2g/cm³Length 4.7m, 2 in total;

step (2): respectively carrying out primary vacuum consumable arc melting on the integral electrode obtained in the step (1), wherein the vacuum degree is less than or equal to 5.0Pa, the melting current is 28-38 kA, the melting voltage is 30-40V, the diameter phi 833mm of a crystallizer of a melting crucible, and the cooling time is more than or equal to 5 hours;

and (3): carrying out furnace welding on the 2 primary ingots obtained in the step (2) in a crucible crystallizer with the diameter phi of 960mm, wherein the welding vacuum degree is less than or equal to 5.0Pa, the welding current is 12-20 kA, and the welding voltage is 31-35V;

and (4): carrying out secondary vacuum consumable melting on the primary ingot with the unit weight of 10t obtained in the step (3), wherein the vacuum degree is less than or equal to 3.0Pa, the melting current is 34-38 kA, the melting voltage is 33-40V, the diameter of a crystallizer of a melting crucible is phi 960mm, and the cooling time after melting is not less than 7 hours;

and (5): carrying out third vacuum consumable melting on the secondary ingot obtained in the step (4), wherein the vacuum degree is less than or equal to 3.0Pa, the melting current is 34-38 kA, the melting voltage is 33-40V, the diameter of a melting crucible crystallizer is phi 1150mm, feeding is started when the consumable electrode melts the residual weight of 300-400 kg, the melting current is gradually reduced, and the cooling time after melting is not less than 7 hours;

and (6): and (4) smelting the ingot with the single weight of 10t and the diameter phi of 1150mm obtained in the step (5) through a vacuum arc furnace, and performing surface turning machining to obtain a TC4 titanium alloy finished product ingot.

The chemical composition at the longitudinal 3-point of the TC4 titanium alloy ingot of example 2 was measured by the above-mentioned test method specified by the national standard, and the results are shown in table 2.

TABLE 2 sampling test results of chemical composition of TC4 titanium alloy ingot in longitudinal 3 points of example 2

Sampling site	Al	V	O	Fe	C	N	H
								Upper part	6.10	4.02	0.15	0.16	0.004	0.002	0.0010
Middle part	6.13	3.96	0.16	0.17	0.008	0.004	0.0008
								Lower part	6.05	4.10	0.15	0.18	0.006	0.004	0.0012
Standard requirements	5.5～6.75	3.5～4.5	≤0.20	≤0.30	≤0.08	≤0.05	≤0.015

Example 3:

a preparation method of titanium and titanium alloy ingots with the weight of 10 t-15 t comprises the following steps:

step (1): according to the proportioning requirement of industrial pure titanium in the national standard GB/T3620.1, sponge titanium, Ti-32Fe intermediate alloy and TiO₂Powder with total weight of 15t and total component weight of 100 percent is uniformly mixed, the uniformly mixed raw materials are pressed into a single-weight 7.5t integral electrode in an integral electrode press, the diameter of the integral electrode is 650mm, and the density is 3.4g/cm³Length 6.6m, 2 in total;

step (2): respectively carrying out primary vacuum consumable arc melting on the integral electrode obtained in the step (1), wherein the vacuum degree is less than or equal to 5.0Pa, the melting current is 25-32 kA, the melting voltage is 28-38V, the diameter phi 833mm of a crystallizer of a melting crucible is reduced, and the cooling time is more than or equal to 5 hours;

and (3): carrying out furnace welding on the 2 primary ingots obtained in the step (2) in a crucible crystallizer with the diameter phi of 960mm, wherein the welding vacuum degree is less than or equal to 5.0Pa, the welding current is 8-20 kA, and the welding voltage is 28-35V;

and (4): carrying out secondary vacuum consumable melting on the primary ingot with the unit weight of 15t obtained in the step (3), wherein the vacuum degree is less than or equal to 3.0Pa, the melting current is 32-36 kA, the melting voltage is 33-40V, the diameter of a crystallizer of a melting crucible is phi 960mm, and the cooling time after melting is not less than 7 hours;

and (5): carrying out third vacuum consumable melting on the secondary ingot obtained in the step (4), wherein the vacuum degree is less than or equal to 3.0Pa, the melting current is 32-36 kA, the melting voltage is 33-40V, the diameter of a melting crucible crystallizer is phi 1150mm, feeding is started when the consumable electrode melts the residual weight of 300-400 kg, the melting current is gradually reduced, and the cooling time after melting is not less than 7 hours;

and (6): and (4) smelting the ingot with the single weight of 15t and the diameter phi of 1150mm obtained in the step (5) through a vacuum arc furnace, and performing surface turning machining to obtain the industrial pure titanium finished product ingot.

The chemical composition of 9 transverse points of the industrial pure titanium ingot of example 3 was measured by the above-mentioned detection method specified by the national standard, and the results are shown in table 3.

TABLE 3 sample test results for transverse 9-point chemical composition of industrial pure titanium ingot of example 3

Sampling site	O	Fe	C	N	H
							1#	0.08	0.08	0.003	0.002	0.0010
2#	0.07	0.10	0.005	0.005	0.0012
						3#	0.10	0.11	0.004	0.004	0.0011
4#	0.09	0.08	0.006	0.008	0.0008
						5#	0.08	0.09	0.005	0.004	0.0009
6#	0.09	0.09	0.003	0.006	0.0009
						7#	0.07	0.10	0.007	0.007	0.0012
8#	0.08	0.08	0.005	0.006	0.0010
						9#	0.09	0.09	0.008	0.003	0.0018
Standard requirements	≤0.15	≤0.15	≤0.1	≤0.03	≤0.015

Example 4:

a preparation method of titanium and titanium alloy ingots with the weight of 10 t-15 t comprises the following steps:

step (1): according to the proportioning requirement of TC4 titanium alloy in the national standard GB/T3620.1, sponge titanium, Ti-32Fe intermediate alloy, Al-V intermediate alloy and TiO₂Powder with total weight of 13t and total component weight of 100 percent is uniformly mixed, the uniformly mixed raw materials are pressed into a single-weight 6.5t integral electrode in an integral electrode press, the diameter of the integral electrode is 650mm, and the density is 3.4g/cm³Length 5.8m, 2 in total;

step (2): respectively carrying out primary vacuum consumable arc melting on the integral electrode obtained in the step (1), wherein the vacuum degree is less than or equal to 5.0Pa, the melting current is 30-38 kA, the melting voltage is 32-38V, the diameter phi 833mm of a crystallizer of a melting crucible is reduced, and the cooling time is more than or equal to 5 hours;

and (3): carrying out furnace welding on the 2 primary ingots obtained in the step (2) in a crucible crystallizer with the diameter phi of 960mm, wherein the welding vacuum degree is less than or equal to 5.0Pa, the welding current is 16-30 kA, and the welding voltage is 26-35V;

and (4): carrying out secondary vacuum consumable melting on the primary ingot with the unit weight of 13t obtained in the step (3), wherein the vacuum degree is less than or equal to 3.0Pa, the melting current is 32-38 kA, the melting voltage is 35-40V, the diameter of a crystallizer of a melting crucible is phi 960mm, and the cooling time after melting is not less than 7 hours;

and (5): carrying out third vacuum consumable melting on the secondary ingot obtained in the step (4), wherein the vacuum degree is less than or equal to 3.0Pa, the melting current is 32-38 kA, the melting voltage is 35-40V, the diameter of a melting crucible crystallizer is phi 1150mm, feeding is started when the consumable electrode melts the residual weight of 300-400 kg, the melting current is gradually reduced, and the cooling time after melting is not less than 7 hours;

and (6): and (4) smelting the cast ingot with the single weight of 13t and the diameter of phi 1150mm obtained in the step (5) through a vacuum arc furnace, and performing surface turning machining to obtain a TC4 titanium alloy finished product cast ingot.

The chemical composition of the TC4 titanium alloy ingot of example 4 at 9 o' clock in the transverse direction was measured by the above-mentioned test method specified by the national standard, and the results are shown in table 4.

TABLE 4 sampling test results of 9-point chemical composition in the transverse direction of TC4 titanium alloy ingot of example 4

Sampling site	Al	V	O	Fe	C	N	H
									1#	6.18	4.10	0.13	0.13	0.002	0.007	0.0015
2#	6.20	4.08	0.15	0.14	0.006	0.010	0.0009
								3#	6.10	3.96	0.16	0.16	0.004	0.009	0.0010
4#	6.16	4.10	0.14	0.14	0.008	0.007	0.0013
								5#	6.14	4.12	0.17	0.15	0.005	0.008	0.0014
6#	6.13	4.06	0.15	0.15	0.007	0.004	0.0012
								7#	6.14	4.05	0.13	0.13	0.003	0.006	0.0008
8#	6.22	4.08	0.14	0.17	0.006	0.007	0.0010
								9#	6.15	4.08	0.15	0.15	0.005	0.011	0.0012
Standard requirements	5.5～6.75	3.5～4.5	≤0.20	≤0.30	≤0.08	≤0.05	≤0.015

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-described embodiments. It will be understood by those skilled in the art that various changes, substitutions of equivalents, and alterations can be made without departing from the spirit and scope of the invention.

Claims (9)

1. A preparation method of industrial pure titanium or TC4 titanium alloy ingots with the weight of 10 t-15 t is characterized by comprising the following steps:

step (1): preparing materials according to the proportioning requirement of industrial pure titanium or TC4 titanium alloy in the national standard GB/T3620.1, uniformly mixing, pressing the uniformly mixed raw materials in an integral electrode press to form an integral electrode with the single weight of 5T-7.5T, and preparing two groups in total;

step (2): respectively carrying out first vacuum consumable arc melting on the two groups of integral electrodes obtained in the step (1) to obtain a primary ingot, wherein the vacuum degree is less than or equal to 5.0Pa, the melting current is 25-38 kA, the melting voltage is 28-40V, and the cooling time is more than or equal to 5 hours;

and (3): carrying out furnace welding on the two groups of primary ingots obtained in the step (2), wherein the welding vacuum degree is less than or equal to 5.0Pa, the welding current is 6-30 kA, and the welding voltage is 22-35V;

and (4): carrying out secondary vacuum consumable melting on the ingot with the unit weight of 10 t-15 t obtained in the step (3), wherein the vacuum degree is less than or equal to 3.0Pa, the melting current is 32-38 kA, the melting voltage is 31-40V, and the cooling time after melting is not less than 7 hours;

and (5): and (4) smelting the ingot with the unit weight of 10 t-15 t by using a vacuum arc furnace, and carrying out surface turning machining to obtain the industrial pure titanium or TC4 titanium alloy finished product ingot.

2. The method of claim 1, wherein: the diameter of the whole electrode in the step (1) is 650 mm.

3. The method of claim 2, wherein: and (3) the diameter phi 833mm of the melting crucible crystallizer for the first vacuum consumable arc melting in the step (2).

4. The method of claim 3, wherein: and (3) furnace welding in the step (3) is furnace welding in a crucible crystallizer with the diameter phi of 960 mm.

5. The method of any one of claims 1-3, wherein: the diameter of the smelting crucible crystallizer for the second vacuum consumable smelting in the step (4) is phi 960 mm.

6. The method of claim 5, wherein: and (4) carrying out the second vacuum consumable melting and then carrying out the third vacuum consumable melting, wherein the vacuum degree of the third vacuum consumable melting is less than or equal to 3.0Pa, the melting current is 32-38 kA, the melting voltage is 31-40V, and the cooling time after the melting is not less than 7 hours.

7. The method of claim 6, wherein: the diameter of the smelting crucible crystallizer for the third vacuum consumable smelting is phi 1150 mm.

8. The method of claim 6 or 7, wherein: feeding is started when the consumable electrode is smelted to the last time, wherein the residual weight of the consumable electrode is 300-400 kg.

9. A preparation method of industrial pure titanium or TC4 titanium alloy ingots with the weight of 10 t-15 t is characterized by comprising the following steps:

step (1): the method comprises the steps of proportioning and uniformly mixing industrial pure titanium or TC4 titanium alloy according to the proportioning requirement of national standard GB/T3620.1, pressing the uniformly mixed raw materials into an integral electrode with the single weight of 5T-7.5T in an integral electrode press, wherein the diameter of the integral electrode is 650mm, and the density is 3.2-3.4 g/cm³The length is 4.5-6.5 m, and two groups are prepared in total;

step (2): respectively carrying out first vacuum consumable arc melting on the two groups of integral electrodes obtained in the step (1) to obtain a primary ingot, wherein the vacuum degree is less than or equal to 5.0Pa, the melting current is 25-38 kA, the melting voltage is 28-40V, the diameter of a melting crucible crystallizer is phi 833mm, and the cooling time is more than or equal to 5 hours;

and (3): carrying out furnace welding on the two groups of primary ingots obtained in the step (2) in a crucible crystallizer with the diameter phi of 960mm, wherein the welding vacuum degree is less than or equal to 5.0Pa, the welding current is 6-30 kA, and the welding voltage is 22-35V;

and (4): carrying out secondary vacuum consumable melting on the ingot with the unit weight of 10 t-15 t obtained in the step (3), wherein the vacuum degree is less than or equal to 3.0Pa, the melting current is 32-38 kA, the melting voltage is 31-40V, the diameter of a melting crucible crystallizer is phi 960mm, and the cooling time after melting is not less than 7 hours;

and (5): carrying out third vacuum consumable melting on the ingot with the unit weight of 10 t-15 t obtained in the step (4), wherein the vacuum degree is less than or equal to 3.0Pa, the melting current is 32-38 kA, the melting voltage is 31-40V, the diameter of a melting crucible crystallizer is phi 1150mm, feeding is started when the consumable electrode melts the residual weight of 300-400 kg, the melting current is gradually reduced, and the cooling time after melting is not less than 7 hours;

and (6): and (4) smelting the ingot with the unit weight of 10 t-15 t by using the vacuum arc furnace obtained in the step (5), and carrying out surface turning machining to obtain the industrial pure titanium or TC4 titanium alloy finished product ingot.

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