Titanium sponge lump smelting equipment and smelting method

Abstract

The present application relates to a titanium sponge lump smelting device and a smelting method thereof, the scheme includes a furnace chamber, an electron gun, a flash screen observation window, an operating platform, a vacuum interface, a water-cooled cooling bed and a circulating water system; a furnace door that can be opened and closed is provided on the top of the furnace chamber, a flange that can be detachably connected is provided on the bottom, and a crystallizer that cooperates with the water-cooled cooling bed is provided inside; the vacuum interface is connected to a vacuum system, which is composed of a multi-stage vacuum pump, and is used to maintain the vacuum degree of the furnace chamber and the electron gun and to remove the gas released during the smelting process; the circulating water system is respectively connected to the furnace chamber, the vacuum system, the electron gun and the water-cooled cooling bed. The present application can be used for the smelting of titanium sponge lumps, from titanium sponge lumps directly to the primary electrode, which greatly saves the preparation cost of titanium sponge lumps to titanium sponge electrodes, shortens the process flow, and reduces the pollution of titanium sponges in crushing and electrode pressing, and can effectively utilize energy to reduce power consumption, increase metal flow and molten pool depth, thereby improving smelting quality.

Description

Technical Field

[0001] The present application relates to the technical field of titanium ingot production, and in particular to titanium sponge lump smelting equipment and a smelting method thereof. Background Art

[0002] Titanium and titanium alloy ingots can be referred to as titanium ingots. The raw material for producing titanium ingots is sponge titanium, which can be obtained through high-temperature smelting to obtain dense titanium ingots, which is conducive to further forging and processing into titanium materials.

[0003] Since the existing smelting titanium materials are all crushed into sponge titanium lumps, they can only be formed into smelting electrodes after going through the process stages of selection, storage, transportation, material mixing, electrode pressing, and welding. The preparation process of sponge titanium electrodes is cumbersome, and the equipment costs and energy consumption are relatively high. Although the traditional electron gun EB furnace can realize the smelting of large blocks of materials (sponge titanium), it has many shortcomings in smelting methods, energy utilization, material transportation methods, and metal homogenization.

[0004] Therefore, there is an urgent need for a titanium sponge lump smelting equipment and a smelting method thereof, so as to contribute to the research on realizing direct smelting of titanium sponge lumps and saving the complicated process and huge investment and preparation costs from titanium sponge lumps to titanium sponge electrodes. Summary of the invention

[0005] The purpose of this application is to provide a titanium sponge lump smelting device and a smelting method thereof in order to solve the above-mentioned problems existing in the prior art.

[0006] In order to achieve the above application purpose, the present application adopts the following technical scheme: the titanium sponge lump smelting equipment includes a furnace chamber, an electron gun arranged at the top of the furnace chamber, a flash screen observation window arranged at the side of the bottom area of ​​the furnace chamber, an operating platform arranged around the furnace chamber, a vacuum interface arranged at the side of the furnace chamber, a water-cooled cooling bed and a circulating water system arranged in the furnace chamber;

[0007] The top of the furnace chamber is provided with a furnace door that can be opened and closed, the bottom is provided with a detachable flange, and the interior is provided with a crystallizer that cooperates with a water-cooled cooling bed;

[0008] The vacuum interface is connected to a vacuum system, which is composed of a multi-stage vacuum pump and is used to maintain the vacuum degree of the furnace chamber and the electron gun and to remove the gas released during the smelting process;

[0009] The circulating water system is respectively connected to the furnace chamber, the vacuum system, the electron gun and the water-cooled cooling bed, and is used to cool the furnace chamber, the vacuum system, the electron gun and the water-cooled cooling bed;

[0010] The operating platform sets up the furnace chamber at the center and makes the bottom of the furnace chamber suspended in the air, and the vacuum interface and the flash screen observation window are both located below the platform part of the operating platform, and the electron gun is located above the platform part of the operating platform.

[0011] Furthermore, the flash screen observation window includes an observation window made of lead glass and a flash screen device arranged on the observation window.

[0012] Furthermore, the furnace chamber has an inner and outer two-layer structure, the outer layer is used to withstand atmospheric pressure, and the inner layer is used to withstand water pressure.

[0013] Furthermore, the electron gun is an 800KW heat gun, which uses a thyristor power supply as a power source.

[0014] The smelting method of titanium sponge lump smelting equipment comprises the following steps:

[0015] S00, taking titanium sponge lumps, dividing them into a first experimental group and a second experimental group, and obtaining the element contents of the two groups of titanium sponge lumps;

[0016] S10. The bottom of the water-cooled cooling bed is paved with titanium plates of the same brand, and two groups of sponge titanium lumps are respectively placed in the furnace chamber of the corresponding sponge titanium lumps smelting equipment so that the sponge titanium lumps are located at the center of the water-cooled cooling bed. The furnace door is closed and the vacuum system is opened for vacuuming after inspection;

[0017] S20, after the vacuum degree and the leakage rate reach the set threshold, the electron gun is turned on for melting;

[0018] S30, first use an electron gun to scan the middle of the titanium sponge lump to melt it to form a molten pool, and the electron gun scanning pattern is a solid circle;

[0019] When the molten pool no longer deepens, the diameter of the scanning circle is enlarged to expand the formed molten pool, and a gap is scanned near the overflow port as an overflow port, so that the titanium liquid flows out along the overflow port to the outer circle of the titanium lump;

[0020] When the titanium liquid in the molten pool has flowed out, the diameter of the electron gun scanning circle is reduced, and the central circle is scanned continuously, and this process is repeated many times;

[0021] S40, when the titanium liquid flows into the crystallizer through the overflow port, start recording the time and the current water temperature rise, and when the crystallizer is full of liquid, increase the electron gun power to refine the titanium liquid in the crystallizer, record the time, power and water temperature for each refining setting time, and calculate the power loss at different smelting stages according to the recorded time, power and water temperature to obtain power damage data;

[0022] S50, after the smelting of the titanium sponge lump is completed, the power of the first experimental group is turned off to end the smelting and the lump is cooled to obtain an ingot, and the titanium sponge lump of the second experimental group is subjected to a shrinkage feeding operation for a set time, and then the power is turned off to end the smelting and the lump is cooled to obtain an ingot;

[0023] S60, closing the vacuum system, taking the ingots out of the furnace, sampling and testing the finished ingots of the two groups to obtain test data, and analyzing the influence of the smelting process on the composition of the ingots;

[0024] S70, machining the two groups of ingots to obtain smooth ingots, so as to verify the influence of the smelting process on the surface quality of the ingots;

[0025] S80, performing ultrasonic flaw detection on the two groups of light ingots, determining the riser positions of the light ingots and recording the index data of the risers, the index data at least including the riser depth;

[0026] S90. Analyze all recorded data and compare the data differences between the two groups to obtain experimental results.

[0027] Furthermore, in step S60, three points are taken in the axial position of the ingot for sampling, which is required to include at least:

[0028] Sampling is required at the head and bottom within a range of ≤100mm from both ends and on the circumference in the middle; the quantity of each chip sample shall not exceed 25g, and the width of the sampling band shall not exceed 30mm.

[0029] Furthermore, in step S70, the specific steps of machining include:

[0030] S71, performing surface treatment on the ingot by multiple peeling;

[0031] S72, the first cutting is based on the smallest side of the ingot, the feed amount is 1 to 2 mm, and the feed or retraction is adjusted according to the surface quality of the ingot until the first turning is completed;

[0032] S73. Locally treat the surface defects of the ingot, including any one of multiple methods such as turning, peeling, grinding or planing, so that the surface of the ingot after treatment has no steps and corners, the depth-to-width ratio is not greater than 1:6, and the treatment depth is not greater than 10 mm;

[0033] S74, chamfer the ingot head, bottom and corners after interruption, and perform local treatment again on the obvious defects to remove them and complete the processing to obtain a smooth ingot.

[0034] Furthermore, in step S74, it is ensured that the surface roughness Ra of all optical ingots is not greater than 6.3 μm.

[0035] Furthermore, in step S74, with the pinhole at the bottom of the ingot as the center and 50 mm as the radius, defects with a depth exceeding 3 mm and a diameter exceeding 5 mm in the part outside the circumference are removed, and it is allowed to retain a boss with a height of no more than 10 mm formed by removing the defects.

[0036] Furthermore, in step S20, when the vacuum degree is ≤1Pa and the leakage rate is ≤0.2Pa / min, the electron gun is turned on for melting.

[0037] Compared with the prior art, this application has the following beneficial effects:

[0038] 1. This application can remove the water-cooled cooling bed by opening the lower flange of the furnace chamber, place the titanium sponge to be melted on the removed water-cooled cooling bed, put it back on the water-cooled cooling bed and close the flange, start vacuuming, and evacuate the electron gun. After waiting for the vacuuming to be completed, preheat the titanium sponge at a low power, and start scanning and melting with the electron gun after the preheating is completed. During the smelting process, relevant parameters such as water temperature and water flow can be recorded, and experimental operations can be carried out, especially to pave the way for future industrial production, provide relevant data for the design and manufacture of industrial production equipment, and find relevant ways to save energy. Provide relevant experimental basis for industrial application.

[0039] 2. During the experiment, the present application uses an innovative electron gun scanning melting method to effectively utilize raw materials and reduce waste. In addition, opening the gap can significantly reduce the direct contact between the titanium solution and the water-cooled cooling bed, which is equivalent to utilizing sponge titanium ingots to avoid the cooling bed absorbing a large amount of heat, thereby reducing energy waste and significantly reducing heat loss.

[0040] 3. During the experiment, the present application can study whether the top shrinkage feeding operation of the ingot is carried out on the influence of the element content and riser height of the ingot. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the structure of this application;

[0042] Figure 2 is a stereogram of the present application;

[0043] Figure 3 It is the internal structure diagram of this application;

[0044] Figure 4 It is a sampling diagram of this application.

[0045] In the figure, 1. furnace chamber; 2. electron gun; 3. flash screen observation window; 4. operating platform; 5. vacuum interface; 6. water-cooled cooling bed; 7. titanium lump; 11. furnace door; 12. flange. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0047] Those skilled in the art should understand that, in the disclosure of the present application, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be understood as limiting the present application.

[0048] Example 1

[0049] like Figure 1-4 As shown, the titanium sponge lump smelting equipment comprises a furnace chamber 1, an electron gun 2 arranged at the top of the furnace chamber 1, a flash screen observation window 3 arranged at the side of the bottom area of ​​the furnace chamber 1, an operating platform 4 arranged around the furnace chamber 1, a vacuum interface 5 arranged at the side of the furnace chamber 1, a water-cooled cooling bed 6 arranged in the furnace chamber 1, and a circulating water system;

[0050] In this embodiment, the furnace chamber 1 is provided with a furnace door 11 that can be opened and closed on the top, a detachably connected flange 12 on the bottom, and a crystallizer that cooperates with a water-cooled cooling bed 6 inside; preferably, the furnace chamber 1 adopts a water-cooled structure to ensure the vacuum degree inside the furnace chamber 1 and prevent radiant heat. The outer layer of the structure needs to consider the damage of atmospheric pressure, and the wall thickness needs to be determined by calculation. The inner layer must be able to withstand water pressure and not deform under the cooling water pressure. This provides a corresponding vacuum space for vacuum smelting.

[0051] The water-cooled cooling bed 6 is mainly made of T2 copper, with a specification of Φ680*100mm, and is used to hold the titanium melt produced by smelting and cool it into titanium ingots. The crystallizer, as a prior art, has a specification of Φ340*400, and is mainly installed below the water-cooled cooling bed 6, and is used to receive the titanium melt and cooperate with the electron gun 2 for refining. An ingot pulling mechanism is installed below the crystallizer to pull out the titanium ingot. The crystallizer and the ingot pulling mechanism are not shown in the figure, and are both prior art, so their structures and principles will not be described here.

[0052] In this embodiment, the vacuum interface 5 is connected to a vacuum system (not shown in the attached figure), which is composed of a multi-stage vacuum pump, used to maintain the vacuum degree of the furnace chamber 1 and the electron gun 2 and to remove the gas released during the smelting process; preferably, the vacuum system is mainly composed of a three-stage or four-stage vacuum pump, used to maintain the vacuum degree of the furnace chamber 1 and the electron gun 2, and to remove the gas released during the smelting process to keep the smelting process normal. The reliability and normal operation of the vacuum system are related to the normal operation of the entire experimental furnace. The vacuum system of the furnace chamber 1 is composed of a KT600 diffusion pump (maintaining pump 2X-30), a water-cooled cold trap, a Roots pump ZJP-300, and a LG-70 screw pump. The diffusion pump can maintain a high vacuum in the furnace chamber 1 during smelting and degassing. The diffusion pump with a water-cooled cold trap can reach 5×10-5 Pa, the vacuum system of the electron gun 2 is mainly used to maintain the high vacuum inside the electron gun 2, and is mainly composed of a molecular pump and a front-stage mechanical pump, providing a vacuum environment for the cathode block and heating inside the electron gun 2.

[0053] Among them, the electron gun 2 is an 800KW thermal gun, such as model PYG800H, which is mainly used to emit thermal electron beams to melt the sponge titanium lump 7. The thyristor power supply provides high-voltage power for the electron gun 2. The scanning trajectory of the electron beam can be controlled by the scanning trajectory software. The scannable area is a 60-degree cone bottom area, and any graphics set in the 60-degree cone bottom area can also be scanned.

[0054] In this embodiment, the circulating water system is connected to the furnace chamber 1, the vacuum system, the electron gun 2 and the water-cooled cold bed 6 respectively, and is used to cool the furnace chamber 1, the vacuum system, the electron gun 2 and the water-cooled cold bed 6; preferably, the circulating water system (not shown in the figure) is composed of the furnace chamber 1 circulating water drain, the vacuum pump water drain, the electron gun 2 cooling water drain, the cold bed water drain and other parts. The furnace chamber 1 water drain mainly cools the furnace chamber 1, the furnace top, the electron gun seat, the vacuum pipe and other parts. The vacuum pump water drain mainly provides water cooling for the diffusion pump, cold trap, Roots pump, mechanical pump, molecular pump and other pumps that need water cooling. The electron gun 2 water drain is mainly used for water cooling of the heated parts of the electron gun 2. The cold bed water drain is mainly used for cooling the cold bed. Each part of the water drain is provided with a flow switch for detecting the water flow, and the expensive cooling parts such as the gun need to be provided with thermocouples, electronic flow meters, etc. to ensure reliable water supply. The cold bed, power supply and electron gun 2 require independent pure water cooling systems to prevent scale from damaging the equipment.

[0055] In this embodiment, the operation platform 4 sets up the furnace chamber 1 at the center and makes the bottom of the furnace chamber 1 suspended, and the vacuum interface 5 and the flash screen observation window 3 are both located below the platform part of the operation platform 4, and the electron gun 2 is located above the platform part of the operation platform 4. The operation platform 4 is a platform for adjusting the electron gun 2, replacing the cathode block, and operating, etc., and it has an escalator and a guardrail.

[0056] In this embodiment, the flash screen observation window 3 includes an observation window and a flash screen device, which allows the observer to clearly observe the smelting situation in the furnace chamber 1 through a camera system or the naked eye, thereby ensuring the visualization of the smelting process. The observation window uses lead glass to eliminate strong radiation during the smelting process to ensure the health of the observer. The flash screen device can prevent the volatile substances from contaminating the glass surface during the smelting process, making the observation clear and reliable. The principle adopted is the principle of human visual persistence. When the screen flash reaches a certain frequency, people see a continuous image. Preferably, the flash screen device includes a baffle or a transparent film that can switch the opening and closing state at a high speed. Using the principle of visual persistence, in the process of continuous and rapid opening and closing, the human eye cannot perceive the rapid changes, thereby achieving an effect that looks like uninterrupted and clear observation. This is not limited here.

[0057] Example 2

[0058] The smelting method used in Example 1 comprises the following steps:

[0059] S00. Take sponge titanium lump 7, divide it into a first experimental group and a second experimental group, and obtain the element content of the two groups of sponge titanium lump 7; Note: The first experimental group and the second experimental group mentioned here are both experimental tests of a new process for processing using the sponge titanium lump 7 smelting experimental device of the present application. The specific process is the following steps, and the purpose is to repeatedly test and determine the feasibility of the new process.

[0060] In this embodiment, the experimental raw materials are two sponge titanium lumps 7, which are smelted separately and numbered 1# (first experimental group) and 2# (second experimental group). The composition indexes of sponge titanium lumps 7 are shown in Table 1:

[0061] Table 1

[0062]

[0063] Among them, the volumes of the sponge titanium balls 7 are 1#Φ605*310mm and 2#Φ595*300mm respectively.

[0064] S10, the bottom of the water-cooled cooling bed 6 is paved with titanium plates of the same grade, and two groups of sponge titanium lumps 7 are respectively placed in the furnace chamber 1 of the corresponding sponge titanium lumps 7 smelting experimental device, so that the sponge titanium lumps 7 are located at the center of the water-cooled cooling bed 6, and the furnace door 11 is closed and the vacuum system is opened after inspection to evacuate;

[0065] In this embodiment, before placing the titanium sponge lump 7, the bottom of the water-cooled cooling bed 6 is paved with the same grade of plate, the specification of the water-cooled cooling bed 6 is Φ680*100mm, and the thickness of the titanium plate is 15mm. The titanium lump 7 is placed in the center of the cooling bed in the furnace chamber 1, the furnace door 11 is closed, and after checking whether the water, electricity, and gas pipelines are normal, the vacuum system is turned on for evacuation.

[0066] S20, after the vacuum degree and the leakage rate reach the set threshold, start the electron gun 2 for melting;

[0067] In this embodiment, when the vacuum degree is ≤1Pa and the leakage rate is ≤0.2Pa / min, the electron gun 2 can be started for melting.

[0068] S30, first use the electron gun 2 to scan the middle of the titanium sponge lump 7 to melt it to form a molten pool, and the scanning pattern of the electron gun 2 is a solid circle;

[0069] When the molten pool no longer deepens, the diameter of the scanning circle is enlarged to expand the formed molten pool, and a gap is scanned near the overflow port side as an overflow port, so that the titanium liquid flows out along the overflow port to the outer circle of the titanium lump 7;

[0070] When the titanium liquid in the molten pool has flowed out, the diameter of the scanning circle of the electron gun 2 is reduced, and the central circle is continuously scanned, and this is repeated several times;

[0071] S40, when the titanium liquid flows into the crystallizer through the overflow port, start recording the time and the current water temperature rise, and when the crystallizer is full of liquid, increase the power of electron gun 2 (from 0-50-150kw) to refine the titanium liquid in the crystallizer, and record the time, power and water temperature every 5 to 10 minutes of refining, and calculate the power loss at different smelting stages according to the recorded time, power and water temperature (water temperature of the pipeline) to obtain power damage data;

[0072] In this embodiment, the water flow and the temperature difference of the water through the furnace, cooling bed, gun, etc. change with time, and the heat Q = cm △t. As the power of the electron gun 2 changes, the water temperature is constantly changing. The heat loss in the smelting process can be roughly calculated by theoretical calculation from the beginning to the end of the whole process. Among them, c represents specific heat capacity, m represents mass, and △t represents the temperature change value of the object.

[0073] S50, after the smelting of the titanium sponge lump 7 is completed, the power supply of the first experimental group is turned off to end the smelting and the lump is cooled to obtain an ingot, and the titanium sponge lump 7 of the second experimental group is subjected to a shrinkage feeding operation for a set time, and then the power supply is turned off to end the smelting and the lump is cooled to obtain an ingot;

[0074] In this embodiment, after the sponge titanium lump 7 is smelted, 1# is not fed, the smelting power supply is disconnected, and the smelting is finished. After 2# is fed for 30 minutes, the smelting power supply is disconnected, and the smelting is finished. After the smelting is completed, it is cooled for 180 minutes, the vacuum system is turned off, and the ingot is taken out of the furnace.

[0075] Among them, shrinkage compensation is usually achieved by controlling the melting and solidification process, such as adjusting the melting speed, optimizing the mold design, and replenishing the metal liquid by bottom or side feeding, so as to ensure that there is still enough liquid metal to fill the voids formed by shrinkage in the final solidification stage of the casting, so as to obtain a dense titanium alloy ingot without obvious defects. In the VAR method, by continuously consuming the consumable electrode (i.e., sponge titanium lump) and continuously replenishing the molten titanium liquid into the mold, this process helps to reduce the generation of shrinkage cavities and improve the overall quality of the ingot.

[0076] S60, closing the vacuum system, taking the ingots out of the furnace, sampling and testing the finished ingots of the two groups to obtain test data, and analyzing the influence of the smelting process on the composition of the ingots;

[0077] In this embodiment, the finished ingot is sampled and tested to detect the effect of the smelting process on the composition of the ingot. Figure 4 As shown, three-point sampling is performed in the axial direction of the ingot. The specific process is to take chip samples and block analysis samples at the top, middle and bottom of the ingot side surface. Sampling position requirements:

[0078] The head and bottom are required to be sampled within a range of ≤100mm from both ends and on the circumference in the middle. The quantity of each chip sample shall not exceed 25g, and the width of the sampling band shall not exceed 30mm; the block sample size is Ф3×(10-30)mm, and there shall be no defects such as pores, and the quantity shall not be less than 2 pieces. The sample shall not be oxidized, stained with oil, or mixed with other debris. Use a sample bag to store the sample and mark it. It is strictly forbidden to touch the sample with dirty gloves. The sample testing method is shown in Table 2:

[0079] Table 2

[0080] Detection elements Test sample Element detection using standards Fe Chip specimen GB / T-4698.2-2011 C Chip specimen GB / T-4698.14-2011 O Block specimen GB / T-4698.7-2011 N Block specimen GB / T-4698.7-2011 H Block specimen GB / T-4698.15-2011

[0081] S70, machining the two groups of ingots to obtain smooth ingots, so as to verify the influence of the smelting process on the surface quality of the ingots;

[0082] In this embodiment, since the smelted ingot is only a rough ingot with a rough surface and an oxide layer, it can only be processed by the ingot casting machine to obtain a smooth ingot for the next step of processing. The quality of the ingot smelting process will affect various data after the ingot casting machine, such as the thickness of the oxide layer, the depth of the cold shut, etc.

[0083] Preferably, the ingot is peeled multiple times, the first knife feed is based on the smallest edge, the feed amount is controlled at 1-2mm, pay attention to the surface condition during turning, and the knife can be properly fed or retracted according to the surface quality. After the first knife is turned, local treatment can be carried out according to the surface defect condition. It is allowed to use turning peeling, grinding or planing methods to remove local defects on the surface of the ingot. After treatment, the surface of the ingot should be smooth, without steps and corners, the depth-to-width ratio is not greater than 1:6, and the treatment depth is not greater than 10mm. The ingot head, bottom and interrupted corners should be chamfered (45°×10mm~20mm), and if there are obvious cracks, holes and interlayers at the chamfer, they should be turned or polished to remove them. The bottom of the ingot is centered on the ejector hole and has a radius of 50mm. The bottom surface of the part outside this circumference has holes with a depth of more than 3mm and a diameter of more than 5mm, cold shut, copper stains, unmelted sponge titanium, turning chips and other defects that should be removed. A boss with a height not exceeding 10 mm formed by removing defects is allowed.

[0084] S80, performing ultrasonic flaw detection on the two groups of light ingots, determining the riser positions of the light ingots and recording the index data of the risers, the index data at least including the riser depth;

[0085] In this embodiment, the surface roughness Ra of the smooth ingot is ensured to be no greater than 6.3 μm, and an ultrasonic flaw detector CTS-9006-PLUS digital flaw detector is used to perform ingot flaw detection to determine the position of the ingot riser.

[0086] Among them, the riser refers to the cavity formed inside the ingot due to solidification defects during the final solidification process. This cavity will have an adverse effect on the subsequent material processing and use process, and is one of the indicators for judging the quality of the ingot. The shallower the riser position, the better the ingot quality, and the smelting process will affect the riser depth.

[0087] S90. Analyze all recorded data and compare the data differences between the two groups to obtain experimental results.

[0088] In this embodiment, Table 3 and Table 4 respectively show the parameters such as the power of the electron gun 2, the water inlet temperature, the water return temperature, and the water flow rate during the smelting process of the 1# and 2# sponge titanium lumps 7.

[0089] Table 3 1# ingot smelting record data

[0090]

[0091] Table 4 2# ingot smelting record data

[0092]

[0093]

[0094] Among them, the start time is the real time recorded when the experiment is carried out, and the water inlet temperature is related to the actual weather conditions, the operating conditions of the equipment on the day and other factors, so there are differences. However, for the experiments of the two new processes, these effects are not large and are within the error range. Although this application only discloses one test of the two processes, it is not limited to repeated tests by changing the volume of the sponge titanium 7, the refining time in the crystallizer, the power of the electron gun 2, the water temperature, whether to feed shrinkage, how much time to feed shrinkage, etc., and multiple devices can be carried out simultaneously.

[0095] Table 5 Ingot test composition

[0096]

[0097]

[0098] It can be seen that the composition of 1# and 2# ingots meets the requirements of TA1 grade in GB / T-3620.1-2017 Titanium and Titanium Alloy Grades and Chemical Compositions, and is not much different from the original composition of the corresponding sponge titanium lump 7, which conforms to the general electron beam melting composition law. Among them, the iron content of the head of the 1# ingot is 0.015%, which is 0.001% different from the original composition of 0.016% in Table 1, and the iron content of the head of the 2# ingot is 0.055%, which is 0.011% different from the original composition of 0.044% in Table 1. The main reason for this difference in composition is that the top of the 1# ingot is not shrinkage-fed, while the top of the 2# ingot is shrinkage-fed. Shrinkage-fed causes the liquid phase at the top of the ingot to exist for a long time and solidify slowly, which will aggravate the segregation of iron elements, so the iron element at the head of the shrinkage-fed ingot shows a segregation trend.

[0099] Table 6 Ingot machining conditions

[0100]

[0101] From the above data, it can be seen that the surface quality of 1# and 2# ingots is similar, with no obvious difference, and the machining yield is also close. The weight of the other two groups of ingots differed from the raw ingot weight by 25kg and 23kg respectively. This is because there is a drop between the overflow port of the cooling bed and the upper edge of the crystallizer. After the sponge titanium lump 7 is melted, part of the melting remains on the cooling bed, and not all flows into the crystallizer, which eventually leads to a difference between the raw ingot weight and the feed weight after the crystallizer is removed from the furnace. The riser depths of 1# and 2# ingots are 33mm and 91mm respectively. The 1# ingot has no shrinkage compensation, while the 2# ingot has shrinkage compensation, which shows that shrinkage compensation can effectively reduce the riser depth.

[0102] The parts not described in detail in this application are prior art, so this application does not describe them in detail.

[0103] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0104] Although this article uses more terms such as furnace chamber 1, electron gun 2, flash screen observation window 3, operating platform 4, vacuum interface 5, water cooling bed 6, titanium block 7, furnace door 11, flange 12, etc., it does not exclude the possibility of using other terms. These terms are used only to more conveniently describe and explain the essence of this application; interpreting them as any additional restrictions is contrary to the spirit of this application.

[0105] The present application is not limited to the above-mentioned optimal implementation mode. Anyone can derive other forms of products under the inspiration of this application. However, no matter what changes are made in the shape or structure, all technical solutions that are the same or similar to those of the present application fall within the protection scope of the present application.

Claims

1. A smelting method of a titanium sponge lump smelting device, the titanium sponge lump smelting device comprising a furnace chamber, an electron gun arranged at the top of the furnace chamber, a flash screen observation window arranged at the side of the bottom area of ​​the furnace chamber, an operating platform arranged around the furnace chamber, a vacuum interface arranged at the side of the furnace chamber, a water-cooled cooling bed and a circulating water system arranged in the furnace chamber; The furnace chamber is provided with a furnace door that can be opened and closed at the top, a detachably connected flange at the bottom, and a crystallizer that cooperates with the water-cooled cooling bed is provided inside; The vacuum interface is connected to a vacuum system, which is composed of a multi-stage vacuum pump and is used to maintain the vacuum degree of the furnace chamber and the electron gun and to remove the gas released during the smelting process; The circulating water system is respectively connected to the furnace chamber, the vacuum system, the electron gun and the water-cooled cooling bed, and is used to cool the furnace chamber, the vacuum system, the electron gun and the water-cooled cooling bed, and is characterized in that: The smelting method comprises the following steps: S00, taking titanium sponge lumps, dividing them into a first experimental group and a second experimental group, and obtaining the element contents of the two groups of titanium sponge lumps; Among them, the titanium sponge is no longer crushed and is directly melted in a vacuum electron beam furnace; S10. The bottom of the water-cooled cooling bed is paved with titanium plates of the same brand, and two groups of sponge titanium lumps are respectively placed in the furnace chamber of the corresponding sponge titanium lumps smelting equipment so that the sponge titanium lumps are located at the center of the water-cooled cooling bed. The furnace door is closed and the vacuum system is opened for vacuuming after inspection; S20, after the vacuum degree and the leakage rate reach the set threshold, the electron gun is turned on for melting; S30, first use an electron gun to scan the middle of the titanium sponge lump to melt it to form a molten pool, and the electron gun scanning pattern is a solid circle; When the molten pool no longer deepens, the diameter of the scanning circle is enlarged to expand the formed molten pool, and a gap is scanned near the overflow port as an overflow port, so that the titanium liquid flows out along the overflow port to the outer circle of the titanium lump; When the titanium liquid in the molten pool has flowed out, the diameter of the electron gun scanning circle is reduced, and the central circle is scanned continuously, and this process is repeated many times; S40, when the titanium liquid flows into the crystallizer through the overflow port, start recording the time and the current water temperature rise, and when the crystallizer is full of liquid, increase the electron gun power to refine the titanium liquid in the crystallizer, record the time, power and water temperature for each refining setting time, and calculate the power loss at different smelting stages according to the recorded time, power and water temperature to obtain power damage data; S50, after the smelting of the titanium sponge lump is completed, the power of the first experimental group is turned off to end the smelting and the lump is cooled to obtain an ingot, and the titanium sponge lump of the second experimental group is subjected to a shrinkage feeding operation for a set time, and then the power is turned off to end the smelting and the lump is cooled to obtain an ingot; S60, closing the vacuum system, taking the ingots out of the furnace, sampling and testing the finished ingots of the two groups to obtain test data, and analyzing the influence of the smelting process on the composition of the ingots; S70, machining the two groups of ingots to obtain smooth ingots, so as to verify the influence of the smelting process on the surface quality of the ingots; S80, performing ultrasonic flaw detection on the two groups of light ingots, determining the riser positions of the light ingots and recording the index data of the risers, the index data at least including the riser depth; S90. Analyze all recorded data and compare the data differences between the two groups to obtain experimental results.

2. The smelting method according to claim 1, characterized in that: The operating platform sets up the furnace chamber at the center and makes the bottom of the furnace chamber suspended in the air, and the vacuum interface and the flash screen observation window are both located below the platform part of the operating platform, and the electron gun is located above the platform part of the operating platform.

3. The smelting method according to claim 2, characterized in that: The flash screen observation window comprises an observation window made of lead glass and a flash screen device arranged on the observation window.

4. The smelting method according to claim 2, characterized in that: The furnace chamber is a two-layer structure, the outer layer is used to withstand atmospheric pressure, and the inner layer is used to withstand water pressure.

5. The smelting method according to any one of claims 1 to 4, characterized in that: The electron gun is an 800KW heat gun, which uses a thyristor power supply as its power source.

6. The smelting method according to claim 1, characterized in that: In step S60, three points are taken in the axial position of the ingot for sampling, which are required to include at least: Sampling is required at the head and bottom within a range of ≤100mm from both ends and on the circumference in the middle; the quantity of each chip sample shall not exceed 25g, and the width of the sampling band shall not exceed 30mm.

7. The smelting method according to claim 1, characterized in that: In step S70, the specific steps of machining include: S71, performing surface treatment on the ingot by multiple peeling; S72, the first cutting is based on the smallest side of the ingot, the feed amount is 1-2 mm, and the feed or retraction is adjusted according to the surface quality of the ingot until the first turning is completed; S73. Locally treat the surface defects of the ingot, including any one of multiple methods such as turning, peeling, grinding or planing, so that the surface of the ingot after treatment has no steps and corners, the depth-to-width ratio is not greater than 1:6, and the treatment depth is not greater than 10 mm; S74, chamfer the ingot head, bottom and corners after interruption, and perform local treatment again on the obvious defects to remove them and complete the processing to obtain a smooth ingot.

8. The smelting method according to claim 7, characterized in that: In step S74, it is ensured that the surface roughness Ra of all the optical ingots is not greater than 6.3 μm.

9. The smelting method according to claim 7, characterized in that: In step S74, with the pinhole at the bottom of the ingot as the center and 50 mm as the radius, defects with a depth of more than 3 mm and a diameter of more than 5 mm in the part outside the circumference are removed, and it is allowed to retain a boss with a height of no more than 10 mm formed by removing the defects.

10. The smelting method according to any one of claims 7 to 9, characterized in that: In step S20, when the vacuum degree is ≤1Pa and the leakage rate is ≤0.2Pa / min, the electron gun is turned on for melting.

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