Vacuum consumable remelting method for titanium, zirconium and alloy cast ingots of titanium, zirconium and alloy cast ingots of titanium and zirconium

Abstract

The invention belongs to the technical field of smelting, and relates to a vacuum consumable remelting method for titanium, zirconium and alloy cast ingots thereof, which comprises the following steps of: assembling a water-cooled copper crucible and a water-cooled copper base pad, hoisting into titanium, zirconium and alloy consumable electrodes thereof, sealing a furnace, vacuumizing, welding an auxiliary electrode with the same brand after air leakage is qualified, sealing the furnace again, vacuumizing after cooling and vacuum breaking inspection are qualified, and cooling to obtain the titanium, zirconium and alloy cast ingots. The smelting process comprises three stages of arcing, stable smelting and feeding, ingot smelting is completed after feeding is finished, the bottom of a single-smelting-time ingot is cooled and discharged to be in a circular truncated cone shape, the ingot is charged again by turning the head bottom direction of the ingot, and the finished ingot is completed through 1-3 times of smelting. By adopting the bottom pad with the circular truncated cone structure, the area of a bottom chilling area can be reduced, the cold shut defect at the bottom of a cast ingot is effectively improved, and the problem of bottom cold shut cracking during cogging of a finished ingot is solved; and meanwhile, by optimizing the feeding process, full-automatic feeding is achieved, the end face of the head of the cast ingot is flat, and the head shrinkage cavity depth can be stably controlled to be 30-90 mm.

Description

Technical Field

[0001] The invention belongs to the technical field of smelting and relates to a vacuum consumable remelting method for titanium, zirconium and alloy ingots. Background Art

[0002] Vacuum consumable melting is the main method for industrial production of titanium, zirconium and their alloy ingots. For titanium and zirconium, this method has the following advantages: First, it can effectively reduce the atmospheric contamination of metals during the melting process (such as absorption of oxygen, nitrogen and other gas impurities). Second, it can well control the composition and quality of the ingots, thereby obtaining titanium and zirconium ingots with higher purity, which can meet the requirements of key materials in the fields of aerospace, nuclear power, etc.

[0003] With the development of technology in the field of material application, there is an urgent need for large unit weight and large metal parts and components, which promotes the large-scale material manufacturing, and a number of 15-ton or even 20-ton large vacuum consumable furnaces, 10,000-ton fast forging machines and other equipment have emerged. The large-scale ingot casting highlights the limitations of the vacuum consumable remelting method. This method divides the melting process into three stages: arc starting, stable melting and shrinkage feeding. The arc starting and shrinkage feeding stages correspond to the bottom and head of the ingot, respectively, and the following defects are inevitable:

[0004] 1) Cold shut defect at the bottom of the ingot: The larger the diameter, the more serious the cold shut. The finishing process to remove the bottom causes material waste, and the bottom of the ingot is prone to cracking when it is opened, and even the bottom falls off in severe cases.

[0005] 2) Ingot head defects: The larger the ingot size, the deeper the molten pool and the longer the shrinkage feeding time. This process is usually carried out by reserving 100-500kg of electrodes and gradually reducing the smelting power. The existing method relies on manual experience and is affected by the diameter of the auxiliary electrode and the bottom state, and the shrinkage feeding effect fluctuates greatly. When the cover is fully reserved, improper control is prone to occur, and the reserved cover falls off, causing the shrinkage feeding interruption problem; when the cover is not fully reserved, it is easy for the block to 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 the present invention is to overcome the shortcomings of the prior art and provide a vacuum consumable remelting method for titanium, zirconium and alloy ingots. The present invention adopts a water-cooled copper bottom pad with a truncated cone structure with an open upper end to reduce the area of ​​the bottom quenching zone, effectively improve the cold shut defect at the bottom of the ingot, and solve the problem of cold shut cracking at the bottom of the finished ingot. At the same time, for the end structure of the truncated cone ingot, by optimizing the shrinkage feeding process, full-automatic shrinkage feeding is achieved, the shrinkage hole depth of the ingot can be stably controlled at 30 to 90 mm, the end surface of the ingot head is flat, and there is no phenomenon of the reserved cover falling off or the block falling off adhering to the ingot head.

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

[0008] Step S1, assembling a water-cooled copper crucible and a water-cooled copper bottom pad;

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

[0010] Step S3, prepare the auxiliary electrode and assemble it to the electrode rod clamp in the furnace chamber;

[0011] Step S4, preparing a consumable electrode, hoisting it into a water-cooled copper crucible, vertically placing the consumable electrode on the water-cooled copper bottom pad, and adjusting the gap between the consumable electrode and the water-cooled copper crucible;

[0012] Step S5, lowering the furnace chamber to contact and close the water-cooled copper crucible, evacuating the furnace chamber, and performing a leak test. When the leak rate is ≤1.3Pa / min, lower the electrode rod, start the power supply, and weld the auxiliary electrode on the top of the consumable electrode;

[0013] Step S6, after cooling, the vacuum of the furnace chamber is broken, and the welding quality of the auxiliary electrode and the consumable electrode is checked;

[0014] Step S7, after checking that the welding is qualified, put the arc starting material into the water-cooled copper crucible;

[0015] Step S8, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, and a leak test is performed. When the leak rate is ≤1.0Pa / min, the electrode rod is lowered, and the power supply is started. The consumable electrode contacts the arc starting material on the water-cooled copper bottom pad to short-circuit and generate an arc, and enter the arc starting stage;

[0016] Step S9, arc starting stage, the melting power is 30kW to 1500kW, and the melting power gradient increases to quickly improve the molten pool;

[0017] Step S10: After the molten pool is sound, it enters the stable smelting stage, the smelting power is 1500kW to 100kW, and the smelting power gradient decreases;

[0018] Step S11, when the remaining weight of the consumable electrode is M, the feeding stage is automatically entered, the melting power is 1500kW to 30kW, and the melting power gradient is reduced;

[0019] Step S12, shrinking until the remaining weight of the consumable electrode is 2kg to 60kg, automatically lifting the electrode rod, and smelting is completed;

[0020] Step S13, after smelting is completed, the cooling stage begins, and the cooling time is 2h to 12h;

[0021] Step S14: After cooling, the furnace chamber is emptied, the ingot is taken out of the furnace, and necessary cleaning and finishing are performed;

[0022] Step S15, repeating steps S1 to S14 1 to 2 times, exchanging the head and bottom directions of the consumable electrode during each smelting, to complete the smelting of the finished ingot.

[0023] Furthermore, in step S1, the water-cooled copper bottom pad is a truncated cone-shaped structure with an open upper end, and the water-cooled copper crucible is placed on the water-cooled copper bottom pad, and the two are sealed and detachably connected;

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

[0025] The inner depth of the water-cooled copper bottom pad is H = (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 in step S3 and the consumable electrode in step S4 are of the same brand, and the consumable electrode is a consumable electrode of titanium, zirconium and alloys thereof.

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

[0029] Further, in step S10, according to different brands and ingot types of consumable electrodes, the starting smelting power and the ending smelting power of the stable smelting stage are both 100kW to 1500kW, and the starting smelting power of the stable smelting stage is ≥ the ending smelting power of the stable smelting stage, and decreases at a rate of 0kW / h to 100kW / h.

[0030] Furthermore, in step S11, according to different consumable electrode brands and ingot types, the smelting power in the feeding stage is reduced from the end smelting power in the stable stage to 30 kW at a rate of 0 kW / min to 50 kW / min.

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

[0032]

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

[0034] H represents the inner depth of the water-cooled copper pad, m;

[0035] D is the inner diameter of the water-cooled copper crucible, m;

[0036] d represents the inner diameter of the lower end of the water-cooled copper base pad, m.

[0037] Furthermore, in step S11, the shrinkage compensation time for smelting the unfinished product is 10 minutes to 60 minutes, and the shrinkage compensation time for smelting the finished product is 60 minutes to 240 minutes.

[0038] The technical solution provided by the embodiment of the present invention has the following beneficial effects:

[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, thus saving materials and working hours.

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

[0041] (3) The shrinkage feeding stage of the present invention can realize full automatic control, and the shrinkage hole depth can be stably controlled within 30 to 90 mm according to different material and electrode specifications.

[0042] (4) The as-cast end surface of the ingot head of the present invention is smooth and flat, and the end surface does not need to be machined for flattening. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0044] Figure 2 This is a schematic diagram of the structure of the vacuum self-consumable one-time melting titanium ingot in Example 1 of the present invention.

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

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

[0047] Explanation of the accompanying drawings: 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-reserved cover; 9-electric arc; 10-molten pool; 11-secondary smelting and solidification ingot. DETAILED DESCRIPTION

[0048] A vacuum consumable remelting method for titanium, zirconium and alloy ingots thereof comprises the following steps:

[0049] Step S1, assembling a water-cooled copper crucible and a water-cooled copper bottom pad; the water-cooled copper bottom pad is a truncated cone-shaped structure with an open upper end, and the water-cooled copper crucible is placed on the water-cooled copper bottom pad, and the two are sealed and detachably connected;

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

[0051] The inner depth of the water-cooled copper base pad is H = (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 bottom pad are simultaneously hoisted into the smelting station;

[0054] Step S3, prepare the auxiliary electrode and assemble it to the electrode rod clamp in the furnace chamber;

[0055] Step S4, prepare a consumable electrode, hoist it into a water-cooled copper crucible, place the consumable electrode vertically on a water-cooled copper bottom pad, and adjust the gap between the consumable electrode and the water-cooled copper crucible;

[0056] The auxiliary electrode in step S3 is of the same grade as the consumable electrode in step S4, and the consumable electrode is a consumable electrode made of titanium, zirconium or an alloy thereof;

[0057] Step S5, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, and a leak test is performed. When the leak rate is ≤1.3Pa / min, the electrode rod is lowered, the power supply is started, and the auxiliary electrode is welded to the top of the consumable electrode;

[0058] Step S6, after cooling, the furnace chamber is broken into vacuum, and the welding quality of the auxiliary electrode and the consumable electrode is checked;

[0059] Step S7, after checking that the welding is qualified, put the arc starting material into the water-cooled copper crucible;

[0060] Step S8, the furnace chamber is lowered to contact and close with the crucible, the furnace chamber is evacuated, and a leak test is performed. When the leak rate is ≤1.0Pa / min, the electrode rod is lowered, the power supply is started, and the consumable electrode is in contact with the arc starting material on the water-cooled copper bottom pad to short-circuit and generate an arc, and the arc starting stage is entered;

[0061] Step S9, arc starting stage, the melting power is 30kW~1500kW, and the melting power gradient increases to quickly improve the molten pool;

[0062] In step S9, according to the different brands and ingot types of consumable electrodes, the smelting power in the arc starting stage is increased from 30 kW to the starting smelting power in the stable smelting stage at a rate of 50 kW / min to 150 kW / min, and the arc starting time is 3 min to 25 min;

[0063] Step S10: After the molten pool is sound, it enters the stable smelting stage, the smelting power is 1500kW to 100kW, and the smelting power gradient decreases;

[0064] In step S10, according to different consumable electrode brands and ingot types, the starting smelting power and the ending smelting power of the stable smelting stage are both 100kW to 1500kW, and the starting smelting power of the stable smelting stage is ≥ 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 remaining weight of the consumable electrode is M, the feeding stage is automatically entered, the melting power is 1500kW to 30kW, and the melting power gradient is reduced;

[0066] In step S11, according to different consumable electrode brands and ingot types, the smelting power in the feeding stage is reduced from the end smelting power of the stable smelting stage to 30 kW at a rate of 0 kW / min to 50 kW / min;

[0067] Step S12, feeding and shrinking until the remaining weight of the consumable electrode is 2kg to 60kg, automatically lifting the electrode rod, and smelting is completed;

[0068] Step S13, after smelting, enter the cooling stage. Depending on the material and electrode specifications, the cooling time is 2h to 12h;

[0069] Step S14: After cooling, the furnace chamber is emptied, the ingot is taken out of the furnace, and necessary cleaning and finishing are performed;

[0070] Step S15, repeating steps S1 to S14 1 to 2 times, changing the head and bottom directions of the consumable electrode during each smelting, to complete the smelting of the finished ingot.

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

[0072]

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

[0074] H represents the inner depth of the water-cooled copper pad, m;

[0075] D is the inner diameter of the water-cooled copper crucible, m;

[0076] d represents the inner diameter of the lower end of the water-cooled copper base pad, m.

[0077] In step S11, the shrinkage compensation time for unfinished products is 10 minutes to 60 minutes, and the shrinkage compensation time for finished products is 60 minutes to 240 minutes.

[0078] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0079] Example 1

[0080] A method for vacuum consumable remelting of 10 tons of 1060 mm TA1 pure titanium ingot, with two smelting steps, comprises the following steps:

[0081] Step S1, assembling a water-cooled copper crucible and a water-cooled copper bottom pad, placing a cylindrical water-cooled copper crucible with openings at both ends on the water-cooled copper bottom pad, the two are sealed and detachably connected, and the specification of the water-cooled copper crucible for one smelting is Φ980mm;

[0082] The water-cooled copper bottom pad is a truncated cone structure with an open top. Figure 1 As shown, the inner depth of the water-cooled copper bottom pad 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, hoist the water-cooled copper crucible and the water-cooled copper bottom pad into the smelting station at the same time;

[0084] Step S3, prepare TA1 pure titanium auxiliary electrode, and assemble it to the electrode rod clamp in the furnace chamber;

[0085] Step S4, prepare a TA1 pure titanium consumable electrode, the electrode specification is Φ860mm, the weight is 10 tons, hoist it into a Φ980mm crucible, and adjust the gap between the electrode and the crucible R1=60mm;

[0086] Step S5, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, and a leak test is performed. The leak rate is 0.83 Pa / min, which meets the requirements, the electrode rod is lowered, the power supply is started, and the auxiliary electrode is welded to the top of the consumable electrode;

[0087] Step S6, after cooling, the furnace chamber is broken into vacuum, and the welding quality of the auxiliary electrode and the consumable electrode is checked;

[0088] Step S7, after checking that the welding is qualified, put the arc starting material into the water-cooled copper crucible;

[0089] Step S8, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, and a leak test is performed. The leak rate is 0.75 Pa / min, which meets the requirements. The electrode rod is lowered, the power supply is started, and the consumable electrode is in contact with the arc starting material on the water-cooled copper bottom pad to short-circuit and generate an arc, and enter the arc starting stage;

[0090] Step S9, arc starting stage, the melting power is gradually increased, the molten pool is quickly improved, the melting power is increased from 30kW to 1000kW, the power increase rate is 64.7kW / min, and the arc starting time is 15min;

[0091] Step S10: After the molten pool is sound, it enters the stable smelting stage, the smelting power is reduced from 1000kW to 800kW, and the power reduction rate is 20kW / h;

[0092] Step S11, when the remaining weight of the consumable electrode is 200 kg, the feeding stage is automatically entered, and the feeding time for one time is 15 minutes;

[0093] Step S12: When the consumable electrode is reduced to 2 kg, the electrode rod is automatically lifted and the smelting is finished;

[0094] Step S13, after smelting is completed, the cooling stage begins, and the cooling time is 10 hours;

[0095] Step S14: After cooling, the furnace chamber is emptied and the ingot is taken out of the furnace. Figure 2 As shown, carry out necessary cleaning and finishing;

[0096] Step S15, assembling the water-cooled copper crucible and the water-cooled copper bottom pad again, placing the cylindrical water-cooled copper crucible with openings at both ends on the water-cooled copper bottom pad, the two are sealed and detachably connected, and the specification of the water-cooled copper crucible during the secondary smelting is Φ1060mm;

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

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

[0099] Step S17, prepare TA1 pure titanium auxiliary electrode, and assemble it to the electrode rod clamp in the furnace chamber;

[0100] Step S18, prepare a TA1 pure titanium primary ingot with a specification of Φ980 mm and a weight of 10 tons, turn the ingot head-down direction and hoist it into a Φ1060 mm water-cooled copper crucible, and adjust the gap between the primary ingot and the water-cooled copper crucible to R2 = 40 mm;

[0101] Step S19, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, and a leak test is performed. The leak rate is 0.27 Pa / min, which meets the requirements. The electrode rod is lowered, the power supply is started, and the auxiliary electrode is welded to the top of the primary ingot;

[0102] Step S20, after cooling, the furnace chamber is broken into vacuum, and the welding quality between the auxiliary electrode and the primary ingot is checked;

[0103] Step S21, after checking that the welding is qualified, put the arc starting material into the water-cooled copper crucible;

[0104] Step S22, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, and a leak test is performed. The leak rate is 0.25 Pa / min, which meets the requirements. The electrode rod is lowered, the power supply is started, and the primary ingot is in contact with the arc starting material on the water-cooled copper bottom pad to short-circuit and generate an arc, and then the arc starting stage is entered;

[0105] Step S23, arc starting stage, the melting power increases from small to large, the molten pool is quickly improved, the melting power increases from 30kW to 1500kW, the power increase rate is 82kW / min, and the arc starting time is 18min;

[0106] Step S24: After the molten pool is sound, it enters the stable smelting stage, the smelting power is reduced from 1500kW to 1300kW, and the power reduction rate is 25kW / h;

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

[0108] Step S26, when the ingot is reduced to 2kg, the electrode rod is automatically lifted and the smelting is finished;

[0109] Step S27, after smelting, enter the cooling stage, the cooling time is 12h;

[0110] Step S28, after cooling, the furnace chamber is emptied, and the secondary finished ingot is taken out of the furnace. The depth of shrinkage hole detected at the head of the ingot is 70 mm.

[0111] Example 2

[0112] A method for vacuum consumable remelting of 10 tons of Φ1060mm TC4 titanium alloy ingots, three times of melting, the steps are as follows:

[0113] Step S1, assembling a water-cooled copper crucible and a water-cooled copper bottom pad, placing a cylindrical water-cooled copper crucible with openings at both ends on the water-cooled copper bottom pad, the two are sealed and detachably connected, and the specification of the water-cooled copper crucible for one smelting is Φ900mm;

[0114] The water-cooled copper bottom pad is a truncated cone-shaped structure with an open upper end, wherein the inner depth of the water-cooled copper bottom pad is H=1R1=0.05m, wherein R1 is the gap between the water-cooled copper crucible and the consumable electrode.

[0115] Step S2: After assembly, hoist the water-cooled copper crucible and the water-cooled copper bottom pad into the smelting station at the same time;

[0116] Step S3, preparing a TC4 titanium alloy auxiliary electrode and assembling it to the electrode rod clamp in the furnace chamber;

[0117] Step S4, prepare a TC4 titanium alloy consumable electrode, the electrode specification is Φ800mm, the weight is 10 tons, hoist it into a Φ900mm water-cooled copper crucible, and adjust the gap R1 between the consumable electrode and the water-cooled copper crucible to 50mm;

[0118] Step S5, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, and a leak test is performed. The leak rate is 0.67 Pa / min, which meets the requirements. The electrode rod is lowered, the power supply is started, and the auxiliary electrode is welded to the top of the consumable electrode;

[0119] Step S6, after cooling, the furnace chamber is broken into vacuum, and the welding quality of the auxiliary electrode and the consumable electrode is checked;

[0120] Step S7, after checking that the welding is qualified, put the arc starting material into the water-cooled copper crucible;

[0121] Step S8, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, and a leak test is performed. The leak rate is 0.73 Pa / min, which meets the requirements. The electrode rod is lowered, the power supply is started, and the consumable electrode is in contact with the arc starting material on the water-cooled copper bottom pad to short-circuit and generate an arc, and then the arc starting stage is entered;

[0122] Step S9, arc starting stage, the melting power increases from small to large, the molten pool is quickly improved, the melting power increases from 30kW to 900kW, the power increase rate is 72.5kW / min, and the arc starting time is 12min;

[0123] Step S10: After the molten pool is sound, it enters the stable smelting stage, the smelting power is reduced from 900kW to 700kW, and the power reduction rate is 16kW / h;

[0124] Step S11, when the remaining weight of the consumable electrode is 180 kg, the feeding stage is automatically entered, and the feeding time for one time is 20 minutes;

[0125] Step S12: When the consumable electrode is reduced to 2 kg, the electrode rod is automatically lifted and the smelting is finished;

[0126] Step S13, after smelting is completed, the cooling stage begins, and the cooling time is 8 hours;

[0127] Step S14: After cooling, the furnace chamber is emptied, the ingot is taken out of the furnace, and necessary cleaning and finishing are performed;

[0128] Step S15, assembling the water-cooled copper crucible and the water-cooled copper bottom pad again, placing the cylindrical water-cooled copper crucible with openings at both ends on the water-cooled copper bottom pad, the two are sealed and detachably connected, and the specification of the water-cooled copper crucible during the secondary smelting is Φ980mm;

[0129] The water-cooled copper bottom pad is a truncated cone-shaped structure with an open upper end, wherein the inner depth of the water-cooled copper bottom 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 bottom pad are simultaneously hoisted into the smelting station;

[0131] Step S17, prepare TC4 titanium alloy auxiliary electrode, and assemble it to the electrode rod clamp in the furnace chamber;

[0132] Step S18, prepare a TC4 titanium alloy primary ingot, the primary ingot specification is Φ900mm, the weight is 10 tons, turn the head and bottom direction of the primary ingot, hoist it into a Φ980mm crucible, and adjust the gap between the primary ingot and the crucible R2 = 40mm;

[0133] Step S19, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, a leak test is performed, and the leak rate is 0.45 Pa / min, the electrode rod is lowered, the power supply is started, and the auxiliary electrode and the primary ingot are welded;

[0134] Step S20, after cooling, the furnace chamber is broken into vacuum, and the welding quality between the auxiliary electrode and the primary ingot is checked;

[0135] Step S21, after checking that the welding is qualified, the arc starting material is placed in the water-cooled copper crucible;

[0136] Step S22, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, a leak test is performed, and the leak rate is 0.32Pa / min. The electrode rod is lowered, and the power supply is started. The primary ingot contacts the arc starting material on the water-cooled copper bottom pad to short-circuit and generate an arc, and enter the arc starting stage;

[0137] Step S23, arc starting stage, the melting power increases from small to large, the molten pool is quickly improved, the melting power increases from 30kW to 1200kW, the power increase rate is 78kW / min, and the arc starting time is 15min;

[0138] Step S24: After the molten pool is sound, it enters the stable smelting stage, the smelting power is reduced from 1200kW to 900kW, and the power reduction rate is 30kW / h;

[0139] Step S25: Smelt stably 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 enter the shrinkage feeding stage, the smelting power drops from 1200kW to 30kW, the power reduction rate is 39kW / min, and the secondary smelting shrinkage feeding time is 30min;

[0140] Step S26, when the consumable electrode is reduced to 2 kg, the electrode rod is automatically lifted and the smelting is completed;

[0141] Step S27, after smelting, enter the cooling stage, the cooling time is 10 hours;

[0142] Step S28, after cooling is completed, the furnace chamber is emptied, the secondary ingot is taken out of the furnace, and necessary finishing processing is performed;

[0143] Step S29, assembling the water-cooled copper crucible and the water-cooled copper bottom pad again, placing the cylindrical water-cooled copper crucible with openings at both ends on the water-cooled copper bottom pad, the two are sealed and detachably connected, and the specification of the water-cooled copper crucible for the third smelting is Φ1060mm;

[0144] The water-cooled copper bottom pad is a truncated cone-shaped structure with an open upper end, wherein the inner depth of the water-cooled copper bottom pad is H=3R3=0.12m, wherein 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 bottom pad are simultaneously hoisted into the smelting station;

[0146] Step S31, prepare a TC4 titanium alloy auxiliary electrode and assemble it to the electrode rod clamp in the furnace chamber;

[0147] Step S32, prepare a TC4 titanium alloy secondary ingot, the specification of the secondary ingot is Φ980mm, the weight is 10 tons, turn the head and bottom direction of the secondary ingot, hoist it into a Φ1060mm water-cooled copper crucible, and adjust the gap R3 between the secondary ingot and the water-cooled copper crucible to 40mm;

[0148] Step S33, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, a leak test is performed, and the leak rate is 0.33 Pa / min. The electrode rod is lowered, the power supply is started, and the auxiliary electrode is welded to the top of the secondary ingot;

[0149] Step S34, after cooling, the furnace chamber is broken into vacuum, and the welding quality between the auxiliary electrode and the secondary ingot is checked;

[0150] Step S35: After checking that the welding is qualified, put the arc starting material into the water-cooled copper crucible;

[0151] Step S36, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, a leak test is performed, and the leak rate is 0.26Pa / min. The electrode rod is lowered, the power supply is started, and the secondary ingot is in contact with the arc-starting material on the water-cooled copper bottom pad to short-circuit and generate an arc, and enter the arc-starting stage;

[0152] Step S37, arc starting stage, the melting power increases from small to large, the molten pool is quickly improved, the melting power increases from 30kW to 1500kW, the power increase rate is 73.5kW / min, and the arc starting time is 20min;

[0153] Step S38, after the molten pool is sound, it enters the stable smelting stage, and the smelting power is reduced from 1500kW to 1000kW, and the power reduction rate is 62kW / h;

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

[0155] Step S40: When the secondary ingot is reduced to 30 kg, the electrode rod is automatically lifted and the smelting is completed;

[0156] Step S41, after smelting is completed, the cooling stage begins, and the cooling time is 12 hours;

[0157] Step S42, after cooling, the furnace chamber is emptied, and three finished ingots are taken out of the furnace. The depth of shrinkage hole detected at the head of the ingot is 65 mm.

[0158] Example 3

[0159] A method for vacuum consumable remelting of 8 tons of Φ900mm R60702 pure zirconium ingot, two smeltings, the steps are as follows:

[0160] Step S1, assembling a water-cooled copper crucible and a water-cooled copper bottom pad, placing a cylindrical water-cooled copper crucible with openings at both ends on the water-cooled copper bottom pad, the two are sealed and detachably connected, and the specification of the water-cooled copper crucible for one smelting is Φ820mm;

[0161] The water-cooled copper bottom pad is a truncated cone structure with an open upper end, wherein the inner depth of the water-cooled copper bottom pad is H=3R1=0.15m, wherein R is the gap between the water-cooled copper crucible and the consumable electrode.

[0162] Step S2: After assembly, hoist the water-cooled copper crucible and the water-cooled copper bottom pad into the smelting station at the same time;

[0163] Step S3, prepare R60702 pure zirconium auxiliary electrode, and assemble it to the electrode rod clamp in the furnace chamber;

[0164] Step S4, prepare R60702 pure zirconium consumable electrode, the electrode specification is Φ720mm, the weight is 8 tons, hoist it into Φ820mm water-cooled copper crucible, and adjust the gap between the electrode and the water-cooled copper crucible R1=50mm;

[0165] Step S5, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, a leak test is performed, and the leak rate is 0.73 Pa / min, the electrode rod is lowered, the power supply is started, and the auxiliary electrode is welded to the top of the consumable electrode;

[0166] Step S6, after cooling, the furnace chamber is broken into vacuum, and the welding quality of the auxiliary electrode and the consumable electrode is checked;

[0167] Step S7, after checking that the welding is qualified, put the arc starting material into the water-cooled copper crucible;

[0168] Step S8, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, a leak test is performed, and the leak rate is 0.65 Pa / min. The electrode rod is lowered, the power supply is started, and the consumable electrode is in contact with the arc starting material on the water-cooled copper bottom pad to short-circuit and generate an arc, and enter the arc starting stage;

[0169] Step S9, arc starting stage, the melting power increases from small to large, the molten pool is quickly improved, the melting power increases from 30kW to 900kW, the power increase rate is 54.4kW / min, and the arc starting time is 16min;

[0170] Step S10: After the molten pool is sound, it enters the stable smelting stage, the smelting power is reduced from 900kW to 700kW, and the power reduction rate is 28kW / h;

[0171] Step S11, when the remaining weight of the consumable electrode is 150 kg, the feeding stage is automatically entered, and the feeding time for one time is 10 minutes;

[0172] Step S12: When the consumable electrode is reduced to 5 kg, the electrode rod is automatically lifted and the smelting is completed;

[0173] Step S13, after smelting, enter the cooling stage, the cooling time is 7h;

[0174] Step S14: After cooling, the furnace chamber is emptied, the ingot is taken out of the furnace, and necessary cleaning and finishing are performed;

[0175] Step S15, assembling a water-cooled copper crucible and a water-cooled copper bottom pad, placing a cylindrical water-cooled copper crucible with openings at both ends on the water-cooled copper bottom pad, the two are sealed and detachably connected, and the specification of the secondary smelting water-cooled copper crucible is Φ900mm;

[0176] The water-cooled copper bottom pad is a truncated cone structure with an open upper end, wherein the inner depth of the water-cooled copper bottom pad is H=3R2=0.12m, wherein 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 bottom pad are simultaneously hoisted into the smelting station;

[0178] Step S17, prepare R60702 pure zirconium auxiliary electrode, and assemble it to the electrode rod clamp in the furnace chamber;

[0179] Step S18, prepare a R60702 pure zirconium primary ingot, the primary ingot specification is Φ820mm, the weight is 8 tons, turn the primary ingot head and bottom direction, hoist it into a Φ900mm water-cooled copper crucible, and adjust the gap between the primary ingot and the water-cooled copper crucible to R2 = 40mm;

[0180] Step S19, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, a leak test is performed, and the leak rate is 0.56 Pa / min. The electrode rod is lowered, the power supply is started, and the auxiliary electrode is welded to the top of the primary ingot;

[0181] Step S20, after cooling, the furnace chamber is broken into vacuum, and the welding quality between the auxiliary electrode and the primary ingot is checked;

[0182] Step S21, after checking that the welding is qualified, put the arc starting material into the water-cooled copper crucible;

[0183] Step S22, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, a leak test is performed, and the leak rate is 0.38Pa / min. The electrode rod is lowered, and the power supply is started. The primary ingot contacts the arc starting material on the water-cooled copper bottom pad to short-circuit and generate an arc, and the arc starting stage is entered;

[0184] Step S23, arc starting stage, the melting power increases from small to large, the molten pool is quickly improved, the melting power increases from 30kW to 1300kW, the power increase rate is 63.5kW / min, and the arc starting time is 20min;

[0185] Step S24: After the molten pool is sound, it enters the stable smelting stage, the smelting power is reduced from 1300kW to 1000kW, and the power reduction rate is 50kW / h;

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

[0187] Step S26, when the ingot is reduced to 5kg, the electrode rod is automatically lifted and the smelting is finished;

[0188] Step S27, after smelting, enter the cooling stage, the cooling time is 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 hole detected at the head of the ingot is 60 mm.

[0190] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A vacuum consumable remelting method for titanium, zirconium and alloy ingots, characterized in that: The following steps are involved: Step S1, assembling a water-cooled copper crucible and a water-cooled copper bottom pad; Step S2, after assembly, the water-cooled copper crucible and the water-cooled copper bottom pad are simultaneously hoisted into the smelting station; Step S3, prepare the auxiliary electrode and assemble it to the electrode rod clamp in the furnace chamber; Step S4, preparing a consumable electrode, hoisting it into a water-cooled copper crucible, vertically placing the consumable electrode on the water-cooled copper bottom pad, and adjusting the gap between the consumable electrode and the water-cooled copper crucible; Step S5, lowering the furnace chamber to contact and close the water-cooled copper crucible, evacuating the furnace chamber, and performing a leak test. When the leak rate is ≤1.3Pa / min, lower the electrode rod, start the power supply, and weld the auxiliary electrode on the top of the consumable electrode; Step S6, after cooling, the vacuum of the furnace chamber is broken, and the welding quality of the auxiliary electrode and the consumable electrode is checked; Step S7, after checking that the welding is qualified, put the arc starting material into the water-cooled copper crucible; Step S8, the furnace chamber is lowered to contact and close with the water-cooled copper crucible, the furnace chamber is evacuated, and a leak test is performed. When the leak rate is ≤1.0Pa / min, the electrode rod is lowered, and the power supply is started. The consumable electrode contacts the arc starting material on the water-cooled copper bottom pad to short-circuit and generate an arc, and enter the arc starting stage; Step S9, arc starting stage, the melting power is 30kW to 1500kW, and the melting power gradient increases to quickly improve the molten pool; Step S10: After the molten pool is sound, it enters the stable smelting stage, the smelting power is 1500kW to 100kW, and the smelting power gradient decreases; Step S11, when the remaining weight of the consumable electrode is M, the feeding stage is automatically entered, the melting power is 1500kW to 30kW, and the melting power gradient is reduced; Step S12, shrinking until the remaining weight of the consumable electrode is 2kg to 60kg, automatically lifting the electrode rod, and smelting is completed; Step S13, after smelting is completed, the cooling stage begins, and the cooling time is 2h to 12h; Step S14: After cooling, the furnace chamber is emptied, the ingot is taken out of the furnace, and necessary cleaning and finishing are performed; Step S15, repeating steps S1 to S14 1 to 2 times, exchanging the head and bottom directions of the consumable electrode during each smelting, to complete the smelting of the finished ingot.

2. The vacuum consumable remelting method of titanium, zirconium and alloy ingots according to claim 1, characterized in that: In step S1, the water-cooled copper bottom pad is a truncated cone-shaped structure with an open upper end, and the water-cooled copper crucible is placed on the water-cooled copper bottom pad, and the two are sealed and detachably connected; The inner diameter d0 of the upper end of the water-cooled copper bottom pad is equal to the inner diameter D of the water-cooled copper crucible, the inner diameter d of the lower end of the water-cooled copper bottom pad is smaller than the inner diameter d0 of the upper end thereof, and the diameter d1 of the consumable electrode is ≤d; The inner depth of the water-cooled copper bottom pad is H = (1-3) × R, m; Where R is the gap between the water-cooled copper crucible and the consumable electrode, m.

3. The vacuum consumable remelting method of titanium, zirconium and alloy ingots according to claim 1, characterized in that: The auxiliary electrode in step S3 and the consumable electrode in step S4 are of the same brand, and the consumable electrode is a consumable electrode made of titanium, zirconium and their alloys.

4. The vacuum consumable remelting method of titanium, zirconium and alloy ingots according to claim 1, characterized in that: In step S9, according to the different brands and ingot types of consumable electrodes, the smelting power in the arc starting stage is increased from 30 kW to the starting smelting power in the stable smelting stage at a rate of 50 kW / min to 150 kW / min, and the arc starting time is 3 min to 25 min.

5. The vacuum consumable remelting method of titanium, zirconium and alloy ingots according to claim 1, characterized in that: In step S10, according to different consumable electrode brands and ingot types, the starting smelting power and the ending smelting power of the stable smelting stage are both 100kW to 1500kW, and the starting smelting power of the stable smelting stage is ≥ the ending smelting power of the stable smelting stage, and decreases at a rate of 0kW / h to 100kW / h.

6. The vacuum consumable remelting method of titanium, zirconium and alloy ingots according to claim 1, characterized in that: In step S11, according to different consumable electrode brands and ingot types, the smelting power in the feeding stage is reduced from the end smelting power of the stable smelting stage to 30 kW at a rate of 0 kW / min to 50 kW / min.

7. The vacuum consumable remelting method of titanium, zirconium and alloy ingots according to claim 1, characterized in that: In step S11, the remaining weight M of the consumable electrode in one smelting is 30 kg to 200 kg, and the remaining weight M of the consumable electrode in subsequent smelting is calculated according to formula (1): ρ represents the density of consumable electrode material, kg / m 3 ; H represents the inner depth of the water-cooled copper pad, m; D is the inner diameter of the water-cooled copper crucible, m; d represents the inner diameter of the lower end of the water-cooled copper base pad, m.

8. The vacuum consumable remelting method of titanium, zirconium and alloy ingots according to claim 1, characterized in that: In step S11, the shrinkage compensation time for unfinished products is 10 minutes to 60 minutes, and the shrinkage compensation time for finished products is 60 minutes to 240 minutes.

Images