Vacuum self-consumption remelting method for titanium, zirconium and alloys thereof

Abstract

The present application belongs to the technical field of smelting, and relates to a vacuum self-consumption remelting method for titanium, zirconium and alloys thereof, which comprises the following steps: after assembling a water-cooled copper crucible and a water-cooled copper bottom pad, hoisting a titanium, zirconium and alloy self-consumption electrode into the crucible, sealing the furnace and pumping, after the leakage is qualified, welding an auxiliary electrode of the same grade, sealing the furnace and pumping again after the cooling and the broken space inspection are qualified, and then smelting after the leakage is qualified, wherein the smelting process comprises three stages of starting arc, stable smelting and feeding, and the smelting of the ingot is completed after the feeding is finished, the bottom of the single smelting ingot is in the shape of a circular truncated cone after being cooled and discharged, the ingot head is turned to the bottom direction and is hoisted into the furnace again, and the finished ingot is obtained after 1-3 times of smelting. The bottom pad with the circular truncated cone structure can reduce the area of the bottom chilling zone, effectively improve the cold shut defects of the ingot bottom, and solve the problem of the cold shut cracking of the bottom of the finished ingot during blooming; meanwhile, the feeding process is optimized, the automatic feeding is realized, the head end surface of the ingot is flat, and the depth of the head shrinkage hole can be stably controlled within 30-90 mm.

Description

Technical Field

[0001] This invention belongs to the field of smelting technology and relates to a vacuum consumable remelting method for titanium, zirconium and their alloy ingots. Background Technology

[0002] Vacuum arc remelting is the primary method for the industrial production of titanium, zirconium, and their alloy ingots. For titanium and zirconium, this method offers several advantages: First, it effectively reduces atmospheric contamination of the metal during the smelting process (e.g., absorption of oxygen, nitrogen, and other gaseous impurities). Second, it allows for precise control over the composition and quality of the ingots, resulting in high-purity titanium and zirconium ingots.

[0003] With the technological advancements in materials applications, the urgent need for large-scale, heavy metal parts and components has driven the trend towards large-scale materials manufacturing, leading to the emergence of equipment such as 15-ton and even 20-ton large vacuum arc remelting furnaces and 10,000-ton high-speed forging machines. The increasing size of ingots highlights the limitations of the vacuum arc remelting method. This method divides the melting process into three stages: arc initiation, stable melting, and feeding. The arc initiation and feeding stages correspond to the bottom and head of the ingot, respectively, inevitably resulting in the following defects:

[0004] 1) Cold shut defect at the bottom of the ingot: The larger the diameter, the more serious the cold shut. Removing the bottom during finishing process results in material waste, and the bottom is prone to cracking during ingot blanking, and in severe cases, the bottom may even fall off.

[0005] 2) Defects at the ingot head: The larger the ingot size and the deeper the molten pool, the longer the feeding time. This process usually involves reserving 100-500 kg of electrode and gradually reducing the melting power. Current methods rely on manual experience, and the feeding effect fluctuates greatly due to the influence of the auxiliary electrode diameter and the bottom condition. When the pre-reserved cap is intact, improper control is prone to occur, and the cap may fall off, causing feeding interruption. When the pre-reserved cap is incomplete, pieces may fall off and stick to the end face of the ingot head, affecting the quality of the head. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a vacuum consumable remelting method for titanium, zirconium, and their alloy ingots. This invention employs a frustum-shaped, top-opening water-cooled copper base pad, reducing the area of ​​the bottom cooling zone and effectively improving the cold shut defect at the bottom of the ingot. This solves the problem of cold shut cracking at the bottom of the finished ingot. Simultaneously, for the frustum-shaped ingot end structure, the feeding process is optimized to achieve fully automated feeding, and the ingot shrinkage cavity depth can be stably controlled between 30 and 90 mm. The ingot head end face is flat, and there is no phenomenon of the pre-reserved cover falling off or pieces adhering to the ingot head.

[0007] To achieve the above technical objectives, the technical solution adopted in this embodiment of the invention is: a vacuum arc remelting method for titanium, zirconium, and their alloy ingots, comprising the following steps:

[0008] Step S1: Assemble the water-cooled copper crucible and the water-cooled copper base;

[0009] Step S2: After assembly, the water-cooled copper crucible and the water-cooled copper base pad are simultaneously hoisted into the smelting station;

[0010] Step S3: Prepare the auxiliary electrode and assemble it into the electrode rod clamp in the furnace chamber;

[0011] Step S4: Prepare the consumable electrode, hoist it into the water-cooled copper crucible, place the consumable electrode vertically on the water-cooled copper base, and adjust the gap between the consumable electrode and the water-cooled copper crucible.

[0012] Step S5: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, and test for leaks. When the leakage rate is ≤1.3Pa / min, lower the electrode rod, start the power supply, and weld the auxiliary electrode to the top of the consumable electrode.

[0013] Step S6: After cooling, break the vacuum in the furnace chamber and check the welding quality of the auxiliary electrode and the consumable electrode;

[0014] Step S7: After inspecting the welding and confirming its quality, place the arc-starting material into the water-cooled copper crucible;

[0015] Step S8: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, and test for leaks. When the leakage rate is ≤1.0Pa / min, lower the electrode rod, start the power supply, and the self-consuming electrode contacts the arc-starting material on the water-cooled copper base to short-circuit and generate electricity to start the arc, thus entering the arc-starting stage.

[0016] Step S9, the arc-starting stage, the smelting power is 30kW to 1500kW, and the smelting power gradient increases rapidly to quickly build up the molten pool;

[0017] Step S10: After the molten pool is well-established, the smelting process enters a stable smelting stage with a smelting power of 1500kW to 100kW, and the smelting power gradient decreases.

[0018] Step S11: When the smelting is stable until the remaining weight of the consumable electrode is M, it automatically enters the feeding stage, with a smelting power of 1500kW to 30kW and a decreasing smelting power gradient.

[0019] Step S12: Compress until the remaining weight of the consumable electrode is 2kg to 60kg, then automatically lift the electrode rod to complete the melting process;

[0020] Step S13: After melting, the process enters the cooling stage, which lasts for 2 to 12 hours.

[0021] Step S14: After cooling is complete, the furnace chamber is emptied, the ingot is removed from the furnace, and then cleaned and finished.

[0022] Step S15: Repeat steps S1 to S14 1 to 2 times, changing the head and bottom orientation of the consumable electrode each time during melting to complete the melting of the finished ingot.

[0023] Furthermore, in step S1, the water-cooled copper base pad is a frustum-shaped structure with an open top, and the water-cooled copper crucible is placed on the water-cooled copper base pad. The two are sealed and detachably connected.

[0024] The upper inner diameter d0 of the water-cooled copper base pad is equal to the inner diameter D of the water-cooled copper crucible, the lower inner diameter d of the water-cooled copper base pad is smaller than its upper inner diameter d0, and the diameter d1 of the consumable electrode is ≤ d.

[0025] The inner depth H of the water-cooled copper base pad is (1~3)×R, m;

[0026] Where R is the gap between the water-cooled copper crucible and the consumable electrode, m.

[0027] Furthermore, the auxiliary electrode mentioned in step S3 has the same grade as the consumable electrode mentioned in step S4, and the consumable electrode is a consumable electrode of titanium, zirconium and their alloys.

[0028] Furthermore, in step S9, depending on the consumable electrode grade and ingot type, the melting power during the arc ignition stage is increased from 30kW to the initial melting power during the stable melting stage at a rate of 50kW / min to 150kW / min, and the arc ignition time is 3min to 25min.

[0029] Furthermore, in step S10, depending on the consumable electrode grade and ingot type, the starting smelting power and ending smelting power of the stable smelting stage are both 100kW to 1500kW, and the starting smelting power of the stable smelting stage is greater than or equal to the ending smelting power of the stable smelting stage, decreasing at a rate of 0kW / h to 100kW / h.

[0030] Furthermore, in step S11, depending on the consumable electrode grade and ingot type, the smelting power during the feeding stage decreases from the smelting power at the end of the stable stage to 30kW at a rate of 0kW / min to 50kW / min.

[0031] Further, in step S11, the remaining weight M of the consumable electrode during one melting is 30kg to 200kg, and the remaining weight M of the consumable electrode in subsequent meltings is calculated according to formula (1):

[0032] (1),

[0033] ρ represents the density of the consumable electrode material, kg / m³ 3 ;

[0034] H represents the inner depth of the water-cooled copper base pad, in meters (m).

[0035] D represents the inner diameter of the water-cooled copper crucible, in meters (m).

[0036] d This indicates the lower inner diameter of the water-cooled copper base pad, in meters (m).

[0037] Furthermore, in step S11, the non-finished product melting and feeding time is 10 min to 60 min, and the finished product melting and feeding time is 60 min to 240 min.

[0038] The beneficial effects of the technical solution provided by the embodiments of the present invention are as follows:

[0039] (1) The cold shut defect at the bottom of the ingot obtained by the present invention is significantly improved, and no machining is required, saving materials and time.

[0040] (2) The bottom of the ingot obtained by the present invention is a frustum, which avoids the end shrinkage caused by uneven metal flow during forging and drawing.

[0041] (3) The shrinkage stage of the present invention can be fully automatically controlled. Depending on the material and electrode specifications, the shrinkage depth can be stably controlled between 30 and 90 mm.

[0042] (4) The ingot head of the present invention has a smooth and flat as-cast end face, and the end face does not require machining flattening treatment. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the structure inside the crucible during vacuum self-consumable primary melting of titanium ingots in Embodiment 1 of the present invention.

[0044] Figure 2 This is a schematic diagram of the structure of a vacuum self-consumable primary melting titanium ingot according to Embodiment 1 of the present invention.

[0045] Figure 3 This is a schematic diagram of the structure inside the crucible during vacuum self-consumable secondary melting of titanium ingots in Embodiment 1 of the present invention.

[0046] Figure 4 This is a schematic diagram of the crucible feeding stage during the vacuum self-consumable secondary melting of titanium ingots in Embodiment 1 of the present invention.

[0047] Explanation of reference numerals in the attached diagram: 1-Water-cooled copper base pad; 2-Water-cooled copper crucible; 3-Consumable electrode; 4-Auxiliary electrode; 5-Primary ingot; 6-Primary ingot head; 7-Primary ingot bottom; 8-Pre-reserved cover; 9-Electric arc; 10-Melting pool; 11-Secondary melting and solidification ingot. Detailed Implementation

[0048] A vacuum arc remelting method for titanium, zirconium, and their alloy ingots includes the following steps:

[0049] Step S1: Assemble the water-cooled copper crucible and the water-cooled copper base pad; the water-cooled copper base pad is a frustum-shaped structure with an open top, and the water-cooled copper crucible is placed on the water-cooled copper base pad. The two are sealed and detachably connected.

[0050] The upper inner diameter d0 of the water-cooled copper base pad is equal to the inner diameter D of the water-cooled copper crucible, the lower inner diameter d of the water-cooled copper base pad is smaller than its upper inner diameter d0, and the diameter d1 of the consumable electrode is ≤ d.

[0051] The inner depth H of the water-cooled copper base pad is (1~3)×R, m;

[0052] Where R is the gap between the water-cooled copper crucible and the consumable electrode, m.

[0053] Step S2: After assembly, the water-cooled copper crucible and the water-cooled copper base pad are simultaneously hoisted into the smelting station;

[0054] Step S3: Prepare the auxiliary electrode and assemble it into the electrode rod clamp in the furnace chamber;

[0055] Step S4: Prepare the consumable electrode, hoist it into the water-cooled copper crucible, place the consumable electrode vertically on the water-cooled copper base, and adjust the gap between the consumable electrode and the water-cooled copper crucible.

[0056] In step S3, the auxiliary electrode has the same grade as the consumable electrode in step S4. The consumable electrode is a consumable electrode made of titanium, zirconium, or their alloys.

[0057] Step S5: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, and test for leaks. When the leakage rate is ≤1.3Pa / min, lower the electrode rod, start the power supply, and weld the auxiliary electrode to the top of the consumable electrode.

[0058] Step S6: After cooling, break the vacuum in the furnace chamber and check the welding quality of the auxiliary electrode and the consumable electrode.

[0059] Step S7: After inspecting the welding and confirming its quality, place the arc-starting material into the water-cooled copper crucible;

[0060] Step S8: Lower the furnace chamber to close the crucible, evacuate the furnace chamber, and test for leaks. When the leakage rate is ≤1.0Pa / min, lower the electrode rod, start the power supply, and short-circuit the self-consumable electrode to generate electricity and ignite the arc by contacting the arc-starting material on the water-cooled copper base pad, thus entering the arc-starting stage.

[0061] Step S9, the arc-starting stage, the smelting power is 30kW to 1500kW, and the smelting power gradient increases rapidly to quickly build up the molten pool;

[0062] In step S9, depending on the consumable electrode grade and ingot type, the melting power during the arc initiation stage is increased from 30kW to the initial melting power during the stable melting stage at a rate of 50kW / min to 150kW / min, and the arc initiation time is 3min to 25min.

[0063] Step S10: After the molten pool is well-established, the smelting process enters a stable smelting stage with a smelting power of 1500kW to 100kW, and the smelting power gradient decreases.

[0064] In step S10, depending on the consumable electrode grade and ingot type, the starting smelting power and ending smelting power of the stable smelting stage are both 100kW to 1500kW, and the starting smelting power of the stable smelting stage is greater than or equal to the ending smelting power of the stable smelting stage, and decreases at a rate of 0kW / h to 100kW / h.

[0065] Step S11: When the smelting is stabilized until the remaining weight of the consumable electrode is M, the feeding stage is automatically entered, with a smelting power of 1500 kW to 30 kW and a decreasing smelting power gradient.

[0066] In step S11, depending on the consumable electrode grade and ingot type, the smelting power in the feeding stage is reduced from the end smelting power of the stable smelting stage to 30kW at a rate of 0kW / min to 50kW / min.

[0067] Step S12: Compress until the remaining weight of the consumable electrode is 2kg to 60kg, then automatically lift the electrode rod to complete the melting process;

[0068] Step S13: After melting, the cooling stage begins. Depending on the material and electrode specifications, the cooling time is 2 to 12 hours.

[0069] Step S14: After cooling is complete, the furnace chamber is emptied, the ingot is removed from the furnace, and then cleaned and finished.

[0070] Step S15: Repeat steps S1 to S14 1 to 2 times, changing the head and bottom orientation of the consumable electrode each time during melting to complete the melting of the finished ingot.

[0071] In step S11, the remaining weight M of the consumable electrode during one melting is 30kg to 200kg, and the remaining weight M of the consumable electrode in subsequent meltings is calculated according to formula (1):

[0072] (1),

[0073] ρ represents the density of the consumable electrode material, kg / m³ 3 ;

[0074] H represents the inner depth of the water-cooled copper base pad, in meters (m).

[0075] D represents the inner diameter of the water-cooled copper crucible, in meters (m).

[0076] d This indicates the lower inner diameter of the water-cooled copper base pad, in meters (m).

[0077] In step S11, the non-finished product melting and feeding time is 10 min to 60 min, and the finished product melting and feeding time is 60 min to 240 min.

[0078] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0079] Example 1

[0080] A method for vacuum consumable remelting of 10 tons of Φ1060mm TA1 pure titanium ingots, involving two melting processes, includes the following steps:

[0081] Step S1: Assemble the water-cooled copper crucible and the water-cooled copper base pad. Place the cylindrical water-cooled copper crucible with open ends on the water-cooled copper base pad. The two are sealed and detachably connected. The specification of the water-cooled copper crucible for one-time melting is Φ980mm.

[0082] The water-cooled copper base pad has a frustum-shaped structure with an open top, see... Figure 1 As shown, the inner depth of the water-cooled copper base is H=2R1=0.12m, where R is the gap between the water-cooled copper crucible and the consumable electrode.

[0083] Step S2: After assembly, the water-cooled copper crucible and the water-cooled copper base pad are simultaneously hoisted into the smelting station;

[0084] Step S3: Prepare TA1 pure titanium auxiliary electrode and assemble it into the electrode rod clamp in the furnace chamber.

[0085] Step S4: Prepare a TA1 pure titanium consumable electrode with a specification of Φ860mm and a weight of 10 tons. Hoist it into a Φ980mm crucible and adjust the gap between the electrode and the crucible R1=60mm.

[0086] Step S5: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, and perform a leak test. The leakage rate is 0.83 Pa / min, which meets the requirements. Lower the electrode rod, start the power supply, and weld the auxiliary electrode to the top of the consumable electrode.

[0087] Step S6: After cooling, break the vacuum in the furnace chamber and check the welding quality of the auxiliary electrode and the consumable electrode.

[0088] Step S7: After inspecting the welding and confirming its quality, place the arc-starting material into the water-cooled copper crucible;

[0089] Step S8: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, and test for leaks. The leakage rate is 0.75 Pa / min, which meets the requirements. Lower the electrode rod, start the power supply, and the consumable electrode contacts the arc-starting material on the water-cooled copper base to short-circuit and generate electricity to start the arc, thus entering the arc-starting stage.

[0090] Step S9, the arc ignition stage, the melting power gradually increases, the molten pool is rapidly formed, the melting power increases from 30kW to 1000kW, the power increase rate is 64.7kW / min, and the arc ignition time is 15min;

[0091] Step S10: After the molten pool is established, the smelting process enters a stable smelting stage, with the smelting power decreasing from 1000kW to 800kW at a rate of 20kW / h.

[0092] Step S11: When the smelting is stable until the remaining weight of the consumable electrode is 200kg, it will automatically enter the feeding stage. The feeding time for one smelting is 15min.

[0093] Step S12: When the self-consumable electrode is reduced to 2kg, the electrode rod is automatically lifted, and the melting process ends.

[0094] Step S13: After melting, the process enters the cooling stage, which lasts for 10 hours.

[0095] Step S14: After cooling is complete, the furnace chamber is emptied, and the ingot is discharged from the furnace. Figure 2 As shown, cleaning and finishing processes are carried out;

[0096] Step S15: Reassemble the water-cooled copper crucible and water-cooled copper base. Place the cylindrical water-cooled copper crucible with open ends on the water-cooled copper base. The two are sealed and detachably connected. The specification of the water-cooled copper crucible during the second melting is Φ1060mm.

[0097] The water-cooled copper base pad has a frustum-shaped structure with an open top, see... Figure 3 As shown, the inner depth of the water-cooled copper base pad is H=3R2=0.12m;

[0098] Step S16: After assembly, the water-cooled copper crucible and the water-cooled copper base pad are simultaneously hoisted into the smelting station;

[0099] Step S17: Prepare TA1 pure titanium auxiliary electrode and assemble it into the electrode rod clamp in the furnace chamber.

[0100] Step S18: Prepare a TA1 pure titanium primary ingot with a specification of Φ980mm and a weight of 10 tons. Turn the head bottom direction and hoist it into a Φ1060mm water-cooled copper crucible, and adjust the gap between the primary ingot and the water-cooled copper crucible R2=40mm.

[0101] Step S19: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, perform a leak test, and check for a leakage rate of 0.27 Pa / min, which meets the requirements. Lower the electrode rod, start the power supply, and weld the auxiliary electrode to the top of the primary ingot.

[0102] Step S20: After cooling, break the vacuum in the furnace chamber and check the welding quality between the auxiliary electrode and the primary ingot;

[0103] Step S21: After inspecting the welding and confirming its quality, place the arc-starting material into the water-cooled copper crucible;

[0104] Step S22: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, perform a leak test, and check the leakage rate. The leakage rate is 0.25 Pa / min, which meets the requirements. Lower the electrode rod, start the power supply, and the primary ingot contacts the arc-starting material on the water-cooled copper base to short-circuit and generate electricity to ignite the arc, thus entering the arc-starting stage.

[0105] Step S23, Arc Initiation Stage: The melting power gradually increases from small to large to quickly build up the molten pool. The melting power increases from 30kW to 1500kW, with a power increase rate of 82kW / min and an arc initiation time of 18min.

[0106] Step S24: After the molten pool is established, the smelting process enters a stable smelting stage, with the smelting power decreasing from 1500kW to 1300kW at a rate of 25kW / h.

[0107] Step S25: When the smelting is stabilized until the remaining weight of the ingot is 359 kg (calculated according to formula (1), where ρ = 4500 kg / m), the smelting is stable. 3 , H= (0.12m, D=0.98m, d=0.86m), automatically enters the feeding stage, see... Figure 4 As shown, the smelting power was reduced from 1300kW to 30kW, the power reduction rate was 6kW / min, and the finished product smelting and feeding time was 210min;

[0108] Step S26: When the remaining amount of the ingot is 2kg after replenishment, the electrode rod is automatically lifted, and the melting process ends.

[0109] Step S27: After melting, the process enters the cooling stage, which lasts for 12 hours.

[0110] Step S28: After cooling, the furnace chamber is emptied and the secondary finished ingot is discharged from the furnace. The depth of shrinkage cavity in the ingot head is 70mm.

[0111] Example 2

[0112] A method for vacuum arc remelting of 10 tons of Φ1060mm TC4 titanium alloy ingots, involving three melting processes, is as follows:

[0113] Step S1: Assemble the water-cooled copper crucible and the water-cooled copper base pad. Place the cylindrical water-cooled copper crucible with open ends on the water-cooled copper base pad. The two are sealed and detachably connected. The specification of the water-cooled copper crucible for one-time melting is Φ900mm.

[0114] The water-cooled copper base pad is a frustum-shaped structure with an open top. The inner depth of the water-cooled copper base pad is H=1R1=0.05m, where R1 is the gap between the water-cooled copper crucible and the consumable electrode.

[0115] Step S2: After assembly, the water-cooled copper crucible and the water-cooled copper base pad are simultaneously hoisted into the smelting station;

[0116] Step S3: Prepare TC4 titanium alloy auxiliary electrodes and assemble them into the electrode rod clamps inside the furnace chamber.

[0117] Step S4: Prepare a TC4 titanium alloy consumable electrode with a specification of Φ800mm and a weight of 10 tons. Hoist it into a Φ900mm water-cooled copper crucible and adjust the gap between the consumable electrode and the water-cooled copper crucible to R1=50mm.

[0118] Step S5: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, perform a leak test, and check for a leakage rate of 0.67 Pa / min, which meets the requirements. Lower the electrode rod, start the power supply, and weld the auxiliary electrode to the top of the consumable electrode.

[0119] Step S6: After cooling, break the vacuum in the furnace chamber and check the welding quality of the auxiliary electrode and the consumable electrode.

[0120] Step S7: After inspecting the welding and confirming its quality, place the arc-starting material into the water-cooled copper crucible;

[0121] Step S8: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, perform a leak test, and check the leakage rate. The leakage rate is 0.73 Pa / min, which meets the requirements. Lower the electrode rod, start the power supply, and the consumable electrode contacts the arc-starting material on the water-cooled copper base to short-circuit and generate electricity to start the arc, thus entering the arc-starting stage.

[0122] Step S9, Arc Initiation Stage: The melting power gradually increases from small to large to quickly build up the molten pool. The melting power increases from 30kW to 900kW, with a power increase rate of 72.5kW / min and an arc initiation time of 12min.

[0123] Step S10: After the molten pool is established, the smelting process enters a stable smelting stage, with the smelting power decreasing from 900kW to 700kW at a rate of 16kW / h.

[0124] Step S11: When the remaining weight of the consumable electrode is 180kg after stable melting, the feeding stage is automatically entered, and the feeding time for one melting stage is 20min.

[0125] Step S12: When the self-consumable electrode is reduced to 2kg, the electrode rod is automatically lifted, and the melting process ends.

[0126] Step S13: After melting, the process enters the cooling stage, which lasts for 8 hours.

[0127] Step S14: After cooling is complete, the furnace chamber is emptied, and the ingots are removed from the furnace for cleaning and finishing.

[0128] Step S15: Reassemble the water-cooled copper crucible and water-cooled copper base. Place the cylindrical water-cooled copper crucible with open ends on the water-cooled copper base. The two are sealed and detachably connected. The specifications of the water-cooled copper crucible during the second melting are Φ980mm.

[0129] The water-cooled copper base pad is a frustum-shaped structure with an open top. The inner depth of the water-cooled copper base pad is H=3R2=0.12m, and R2 is the gap between the water-cooled copper crucible and the consumable electrode.

[0130] Step S16: After assembly, the water-cooled copper crucible and the water-cooled copper base pad are simultaneously hoisted into the smelting station;

[0131] Step S17: Prepare TC4 titanium alloy auxiliary electrodes and assemble them into the electrode rod clamps inside the furnace chamber.

[0132] Step S18: Prepare a TC4 titanium alloy primary ingot with a specification of Φ900mm and a weight of 10 tons. Turn the primary ingot in the head and bottom direction and hoist it into a Φ980mm crucible. Adjust the gap between the primary ingot and the crucible to R2=40mm.

[0133] Step S19: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, perform a leak test (leakage rate 0.45 Pa / min), lower the electrode rod, start the power supply, and weld the auxiliary electrode to the primary ingot.

[0134] Step S20: After cooling, break the vacuum in the furnace chamber and check the welding quality between the auxiliary electrode and the primary ingot;

[0135] Step S21: After the welding is inspected and found to be qualified, place the arc-starting material into the water-cooled copper crucible;

[0136] Step S22: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, perform a leak test, and check for a leakage rate of 0.32 Pa / min. Lower the electrode rod, start the power supply, and the primary ingot contacts the arc-starting material on the water-cooled copper base to short-circuit and generate electricity to ignite the arc, thus entering the arc-starting stage.

[0137] Step S23, Arc Initiation Stage: The melting power gradually increases from small to large to quickly build up the molten pool. The melting power increases from 30kW to 1200kW, with a power increase rate of 78kW / min and an arc initiation time of 15min.

[0138] Step S24: After the molten pool is established, the smelting process enters a stable smelting stage, with the smelting power decreasing from 1200kW to 900kW at a rate of 30kW / h.

[0139] Step S25: Stabilize the melting until the remaining weight of the primary ingot is 128 kg (calculated according to formula (1), where ρ = 4500 kg / m). 3 , H=(0.05m, D=0.9m, d=0.8m), automatically enters the feeding stage, the melting power drops from 1200kW to 30kW, the power reduction rate is 39kW / min, and the secondary melting feeding time is 30min;

[0140] Step S26: When the self-consumable electrode is reduced to 2kg, the electrode rod is automatically lifted, and the melting process ends.

[0141] Step S27: After melting, the process enters the cooling stage, which lasts for 10 hours.

[0142] Step S28: After cooling is complete, the furnace chamber is emptied, the secondary ingot is removed from the furnace, and necessary finishing processes are carried out.

[0143] Step S29: Reassemble the water-cooled copper crucible and water-cooled copper base. Place the cylindrical water-cooled copper crucible with open ends on the water-cooled copper base. The two are sealed and detachably connected. The specification of the water-cooled copper crucible for the third smelting is Φ1060mm.

[0144] The water-cooled copper base pad is a frustum-shaped structure with an open top. The inner depth of the water-cooled copper base pad is H=3R3=0.12m, where R3 is the gap between the water-cooled copper crucible and the consumable electrode.

[0145] Step S30: After assembly, the water-cooled copper crucible and the water-cooled copper base pad are simultaneously hoisted into the smelting station;

[0146] Step S31: Prepare TC4 titanium alloy auxiliary electrodes and assemble them into the electrode rod clamps inside the furnace chamber.

[0147] Step S32: Prepare a TC4 titanium alloy secondary ingot with a specification of Φ980mm and a weight of 10 tons. Turn the secondary ingot in the head and bottom direction and hoist it into a Φ1060mm water-cooled copper crucible. Adjust the gap between the secondary ingot and the water-cooled copper crucible to R3=40mm.

[0148] Step S33: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, perform a leak test (leakage rate 0.33 Pa / min), lower the electrode rod, start the power supply, and weld the auxiliary electrode to the top of the secondary ingot.

[0149] Step S34: After cooling, break the vacuum in the furnace chamber and check the welding quality of the auxiliary electrode and the secondary ingot;

[0150] Step S35: After inspecting the welding and confirming its quality, place the arc-starting material into the water-cooled copper crucible;

[0151] Step S36: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, perform a leak test, and check for a leakage rate of 0.26 Pa / min. Lower the electrode rod, start the power supply, and short-circuit the secondary ingot with the arc-starting material on the water-cooled copper base to generate electricity and ignite the arc, thus entering the arc-starting stage.

[0152] Step S37, Arc Initiation Stage: The melting power gradually increases from small to large to quickly build up the molten pool. The melting power increases from 30kW to 1500kW, with a power increase rate of 73.5kW / min and an arc initiation time of 20min.

[0153] Step S38: After the molten pool is established, the smelting power is reduced from 1500kW to 1000kW in the stable smelting stage, with a power reduction rate of 62kW / h.

[0154] Step S39: When the remaining weight of the secondary ingot is 375 kg after stable melting (calculated according to formula (1), where ρ = 4500 kg / m), 3 , H= (0.12m, D=0.98m, d=0.9m), automatically enters the feeding stage, the smelting power drops from 1000kW to 30kW, the power reduction rate is 4.2kW / min, and the finished product smelting feeding time is 230min;

[0155] Step S40: When the secondary ingot is reduced to 30kg, the electrode rod is automatically lifted, and the melting process ends.

[0156] Step S41: After melting, the process enters the cooling stage, which lasts for 12 hours.

[0157] Step S42: After cooling, the furnace chamber is emptied, and the finished ingots are removed from the furnace in three stages. The depth of shrinkage cavities at the ingot head is 65mm.

[0158] Example 3

[0159] A method for vacuum consumable remelting of 8 tons of Φ900mm R60702 pure zirconium ingots, involving two melting processes, is as follows:

[0160] Step S1: Assemble the water-cooled copper crucible and the water-cooled copper base pad. Place the cylindrical water-cooled copper crucible with open ends on the water-cooled copper base pad. The two are sealed and detachably connected. The specification of the water-cooled copper crucible for one-time melting is Φ820mm.

[0161] The water-cooled copper base pad is a frustum-shaped structure with an open top. The inner depth of the water-cooled copper base pad is H=3R1=0.15m, where R is the gap between the water-cooled copper crucible and the consumable electrode.

[0162] Step S2: After assembly, the water-cooled copper crucible and the water-cooled copper base pad are simultaneously hoisted into the smelting station;

[0163] Step S3: Prepare the R60702 pure zirconium auxiliary electrode and assemble it into the electrode rod clamp in the furnace chamber;

[0164] Step S4: Prepare R60702 pure zirconium consumable electrode with a specification of Φ720mm and a weight of 8 tons. Hoist it into a Φ820mm water-cooled copper crucible and adjust the gap between the electrode and the water-cooled copper crucible R1=50mm.

[0165] Step S5: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, perform a leak test (leakage rate 0.73 Pa / min), lower the electrode rod, start the power supply, and weld the auxiliary electrode to the top of the consumable electrode.

[0166] Step S6: After cooling, break the vacuum in the furnace chamber and check the welding quality of the auxiliary electrode and the consumable electrode.

[0167] Step S7: After inspecting the welding and confirming its quality, place the arc-starting material into the water-cooled copper crucible;

[0168] Step S8: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, perform a leak test (leakage rate 0.65 Pa / min), lower the electrode rod, start the power supply, and short-circuit the self-consumable electrode to contact the arc-starting material on the water-cooled copper base to generate electricity and ignite the arc, thus entering the arc-starting stage.

[0169] Step S9, Arc Initiation Stage: The melting power gradually increases from small to large to quickly build up the molten pool. The melting power increases from 30kW to 900kW, with a power increase rate of 54.4kW / min and an arc initiation time of 16min.

[0170] Step S10: After the molten pool is established, the smelting process enters a stable smelting stage, with the smelting power decreasing from 900kW to 700kW at a rate of 28kW / h.

[0171] Step S11: When the remaining weight of the consumable electrode is 150kg after stable melting, the feeding stage is automatically entered, and the feeding time for one melting stage is 10min.

[0172] Step S12: When the self-consumable electrode is reduced to 5kg, the electrode rod is automatically lifted, and the melting process ends.

[0173] Step S13: After melting, the process enters the cooling stage, which lasts for 7 hours.

[0174] Step S14: After cooling is complete, the furnace chamber is emptied, and the ingots are removed from the furnace for cleaning and finishing.

[0175] Step S15: Assemble the water-cooled copper crucible and the water-cooled copper base pad. Place the cylindrical water-cooled copper crucible with open ends on the water-cooled copper base pad. The two are sealed and detachably connected. The specification of the secondary melting water-cooled copper crucible is Φ900mm.

[0176] The water-cooled copper base pad is a frustum-shaped structure with an open top. The inner depth of the water-cooled copper base pad is H=3R2=0.12m, where R is the gap between the water-cooled copper crucible and the consumable electrode.

[0177] Step S16: After assembly, the water-cooled copper crucible and the water-cooled copper base pad are simultaneously hoisted into the smelting station;

[0178] Step S17: Prepare the R60702 pure zirconium auxiliary electrode and assemble it into the electrode rod clamp in the furnace chamber.

[0179] Step S18: Prepare R60702 pure zirconium primary ingots. The primary ingot specifications are Φ820mm and the weight is 8 tons. Turn the primary ingots in the head and bottom direction and hoist them into the Φ900mm water-cooled copper crucible. Adjust the gap between the primary ingots and the water-cooled copper crucible to R2=40mm.

[0180] Step S19: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, perform a leak test (leakage rate 0.56 Pa / min), lower the electrode rod, start the power supply, and weld the auxiliary electrode to the top of the primary ingot.

[0181] Step S20: After cooling, break the vacuum in the furnace chamber and check the welding quality between the auxiliary electrode and the primary ingot;

[0182] Step S21: After inspecting the welding and confirming its quality, place the arc-starting material into the water-cooled copper crucible;

[0183] Step S22: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, perform a leak test, and check for a leakage rate of 0.38 Pa / min. Lower the electrode rod, start the power supply, and short-circuit the primary ingot with the arc-starting material on the water-cooled copper base to generate electricity and ignite the arc, thus entering the arc-starting stage.

[0184] Step S23, Arc Initiation Stage: The melting power gradually increases from small to large to quickly build up the molten pool. The melting power increases from 30kW to 1300kW, with a power increase rate of 63.5kW / min and an arc initiation time of 20min.

[0185] Step S24: After the molten pool is established, the smelting process enters a stable smelting stage, with the smelting power decreasing from 1300kW to 1000kW at a rate of 50kW / h.

[0186] Step S25: When the smelting is stabilized until the remaining weight of the ingot is 455 kg (calculated according to formula (1), where ρ = 6510 kg / m), the smelting is completed. 3 , H= (0.15m, D=0.82m, d=0.72m), automatically enters the feeding stage, the smelting power drops from 1000kW to 30kW, the power reduction rate is 5.4kW / min, and the finished product smelting feeding time is 180min;

[0187] Step S26: When the remaining weight of the ingot is 5kg, the electrode rod is automatically lifted, and the melting process ends.

[0188] Step S27: After melting, the process enters the cooling stage, which lasts for 10 hours.

[0189] Step S28: After cooling, the furnace chamber is emptied and the secondary finished ingot is taken out of the furnace. The depth of shrinkage cavity in the ingot head is 60mm.

[0190] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A vacuum arc remelting method for titanium, zirconium, and their alloy ingots, characterized in that, Includes the following steps: Step S1: Assemble the water-cooled copper crucible and the water-cooled copper base; Step S2: After assembly, the water-cooled copper crucible and the water-cooled copper base pad are simultaneously hoisted into the smelting station; Step S3: Prepare the auxiliary electrode and assemble it into the electrode rod clamp in the furnace chamber; Step S4: Prepare the consumable electrode, hoist it into the water-cooled copper crucible, place the consumable electrode vertically on the water-cooled copper base, and adjust the gap between the consumable electrode and the water-cooled copper crucible. Step S5: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, and test for leaks. When the leakage rate is ≤1.3Pa / min, lower the electrode rod, start the power supply, and weld the auxiliary electrode to the top of the consumable electrode. Step S6: After cooling, break the vacuum in the furnace chamber and check the welding quality of the auxiliary electrode and the consumable electrode; Step S7: After inspecting the welding and confirming its quality, place the arc-starting material into the water-cooled copper crucible; Step S8: Lower the furnace chamber to contact and close the water-cooled copper crucible, evacuate the furnace chamber, and test for leaks. When the leakage rate is ≤1.0Pa / min, lower the electrode rod, start the power supply, and the self-consuming electrode contacts the arc-starting material on the water-cooled copper base to short-circuit and generate electricity to start the arc, thus entering the arc-starting stage. Step S9, the arc-starting stage, the smelting power is 30kW to 1500kW, and the smelting power gradient increases rapidly to quickly build up the molten pool; Step S10: After the molten pool is well-established, the smelting process enters a stable smelting stage with a smelting power of 1500kW to 100kW, and the smelting power gradient decreases. Step S11: When the smelting is stable until the remaining weight of the consumable electrode is 30kg to 200kg, it automatically enters the feeding stage, with a smelting power of 1500kW to 30kW and a decreasing smelting power gradient. Step S12: Compress until the remaining weight of the consumable electrode is 2kg to 60kg, then automatically lift the electrode rod to complete the melting process; Step S13: After melting, the process enters the cooling stage, which lasts for 2 to 12 hours. Step S14: After cooling is complete, the furnace chamber is emptied, the ingot is removed from the furnace, and then cleaned and finished. Step S15: Repeat steps S1 to S14 1 to 2 times, changing the head and bottom orientation of the consumable electrode each time during melting to complete the melting of the finished ingot. In step S1, the water-cooled copper base pad is a frustum-shaped structure with an open top, and the water-cooled copper crucible is placed on the water-cooled copper base pad. The two are sealed and detachably connected. The upper inner diameter d0 of the water-cooled copper base pad is equal to the inner diameter D of the water-cooled copper crucible, the lower inner diameter d of the water-cooled copper base pad is smaller than its upper inner diameter d0, and the diameter d1 of the consumable electrode is ≤ d. The inner depth H of the water-cooled copper base pad is (1~3)×R, m; Where R is the gap between the water-cooled copper crucible and the consumable electrode, m.

2. The vacuum arc remelting method for titanium, zirconium, and their alloy ingots according to claim 1, characterized in that, The auxiliary electrode mentioned in step S3 has the same grade as the consumable electrode mentioned in step S4, and the consumable electrode is a consumable electrode of titanium, zirconium and their alloys.

3. The vacuum arc remelting method for titanium, zirconium, and their alloy ingots according to claim 1, characterized in that, In step S9, depending on the consumable electrode grade and ingot type, the smelting power in the arc ignition stage is increased from 30kW to the initial smelting power in the stable smelting stage at a rate of 50kW / min to 150kW / min, and the arc ignition time is 3min to 25min.

4. The vacuum arc remelting method for titanium, zirconium, and their alloy ingots according to claim 1, characterized in that, In step S10, depending on the consumable electrode grade and ingot type, the starting smelting power and ending smelting power of the stable smelting stage are both 100kW to 1500kW, and the starting smelting power of the stable smelting stage is greater than or equal to the ending smelting power of the stable smelting stage, decreasing at a rate of 0kW / h to 100kW / h.

5. The vacuum arc remelting method for titanium, zirconium, and their alloy ingots according to claim 1, characterized in that, In step S11, depending on the consumable electrode grade and ingot type, the smelting power during the feeding stage is reduced from the end smelting power of the stable smelting stage to 30kW at a rate of 0kW / min to 50kW / min.

6. The vacuum arc remelting method for titanium, zirconium, and their alloy ingots according to claim 1, characterized in that, In step S15, the remaining weight M of the consumable electrode in subsequent melting cycles is calculated according to formula (1): （1）， ρ represents the density of the consumable electrode material, kg / m³ 3 ; H represents the inner depth of the water-cooled copper base pad, in meters (m). D represents the inner diameter of the water-cooled copper crucible, in meters (m). d This indicates the lower inner diameter of the water-cooled copper base pad, in meters (m).

7. The vacuum arc remelting method for titanium, zirconium, and their alloy ingots according to claim 1, characterized in that, In step S11, the non-finished product melting and feeding time is 10 min to 60 min, and the finished product melting and feeding time is 60 min to 240 min.

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