CN116287744A - Super-large-specification high-temperature alloy and preparation method thereof - Google Patents
Super-large-specification high-temperature alloy and preparation method thereof Download PDFInfo
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Abstract
The invention discloses an ultra-large high-temperature alloy and a preparation method thereof, wherein the method comprises the following steps: step 1: controlling the carbon content, the oxygen content and the calcium content in the consumable ingot, pouring by vacuum induction to obtain an electrode E1, and carrying out heat transfer and annealing on the electrode E1; step 2: punching the electrode E1 by using a molybdenum plug to obtain a hollow electrode E2, and selecting an auxiliary electrode for external furnace welding after the surface oxide layer of the hollow electrode E2 is removed by turning and flat-headed; step 3: hoisting the crystallizer and the hollow electrode E2 to a station, and after adjusting the circulating water flow rate, the pipeline flow rate, the vacuum degree in the furnace and the air leakage rate of the crystallizer, opening a compressed helium pipeline to empty air in a capillary pipeline and increasing the pressure in the furnace to 50-150pa; step 4: vacuum consumable remelting comprises an arcing stage, a steady-state stage and a heat-sealing top stage, and step 5: after stopping blowing helium for 60Min, breaking the air and demoulding to obtain the finished product.
Description
Technical Field
The invention belongs to the field of high-temperature alloy manufacturing, and particularly relates to a method for preparing an oversized high-temperature alloy by adopting a vacuum consumable remelting process and a product thereof.
Background
The worldwide rapid growth of clean, reliable and economic energy sources has prompted more urgent demands for the development of new generation gas turbine systems, but the development of new generation energy systems requires ultra-large-sized high-temperature high-strength superalloy discs and bars, and further, nickel-based ultra-large-sized castings and ingots rich in Nb, ti and other easily segregated strengthening elements. The larger the ingot size, the slower the solidification rate, which leads to an increased tendency for the composition of the ingot to be non-uniform, and associated solidification defects, the most typical of which are black and white spots, are also significantly increased. As the ingot final forming process before hot working, vacuum arc remelting is a key for controlling the solidification quality of the ultra-large-size easily segregated superalloy, and the current related technology and invention develop partial work for improving the solidification quality, but do not really solve the solidification control problem of the ultra-large-size vacuum consumable remelting ingot.
Chinese patent CN 111876649B discloses a smelting process of a high-niobium high-temperature alloy large-size ingot and a high-niobium high-temperature alloy large-size ingot casting technology, and the core of the smelting process is to adopt twice vacuum consumable remelting and a conventional helium cooling mode, but with the increase of the specification of the ingot, the conventional low melting speed and ingot solidification gap helium filling technology cannot truly solve the problem that the heat transfer efficiency from the center to the side of a molten pool after the specification is increased is reduced, so that black spot and white spot defects cannot be obviously improved.
The electroslag remelting large ingot technology disclosed in Chinese patent CN 104372177A can cause arcing between electrodes during vacuum consumable remelting, and even cause safety risks of glow power generation.
The helium cooling process for VAR smelting of large-ingot GH4742 alloy disclosed in China patent CN 112981129B is optimized for the helium cooling technology in the solidification shrinkage joint of an ingot, and does not solve the defects of overhigh center of a super-large-specification consumable ingot molten pool, deep temperature of the molten pool and low heat transfer efficiency from the center of the molten pool to the edge of the molten pool. And the traditional helium cooling without breaking the molten pool can cause the problems of serious splashing, thicker ingot shell and the like of the oversized cast ingot. Other technical documents published by various publications are concentrated in the technical optimization category of the traditional vacuum consumable remelting, and the segregation problem of the vacuum consumable remelting of the super-large-specification high-temperature alloy is difficult to breakthrough.
Disclosure of Invention
In order to overcome the defects in the prior art and solve the problem of metallurgical defects generated in the process of oversized high-temperature alloy easy to segregate, the technical scheme of the invention is as follows:
a method of preparing an oversized superalloy comprising the steps of:
step 1: controlling the carbon content in the consumable ingot to be not more than 0.02wt%, the oxygen content to be not more than 12ppm, and the calcium content to be less than 1ppm, pouring by vacuum induction to obtain an electrode E1, and carrying out heat transfer and annealing at 1100 ℃ on the electrode E1;
step 2: punching the electrode E1 by using a molybdenum plug with the diameter not less than 50mm and not more than 20% of the diameter of the electrode E1 to obtain a hollow electrode E2, removing a surface oxide layer of the hollow electrode E2 by turning light and flattening, and then welding outside the furnace by using an auxiliary electrode;
step 3: the preparation before vacuum consumable remelting, hoist crystallizer and hollow electrode E2 to the station, when the circulating water flow of the crystallizer is not lower than 10L/s, the pipeline flow reaches 50L/s, adjust the vacuum degree in the vacuum consumable melting furnace to below 0.1Mpa, when the leak rate is lower than 1Pa/min, open the compressed helium pipeline and empty the air in the capillary pipeline and increase the pressure in the furnace to 50-150Pa, preferably, the invention adopts the compressed low-temperature liquid helium with the purity of more than 99.999% to replace the usual bottled helium, directly fill the low-temperature high-purity helium into the gap between ingot at the lower part of the surface of the molten pool and crystallizer after decompression gasification, and simultaneously, for the technical aspect of the process, adopt high-flow helium to properly break the liquid seal of the liquid molten pool, increase the detected vacuum pressure value in the furnace to 50-150Pa, but the total vacuum degree is strictly forbidden to exceed 200Pa, further strengthen the cooling of the molten pool, form helium plasma with the molten pool by moderate overflow, reduce the thickness of consumable ingot shells to below 2mm, and inhibit the sputtering defect caused by the molten pool from the molten pool, and control the falling of the molten pool;
step 4: the vacuum consumable remelting comprises an arcing stage, a steady-state stage and a heat-sealing top stage, wherein the melting speed setting value entering the steady-state stage is a function of the nickel, niobium and titanium contents and the diameter of the consumable ingot, namely, the melting speed (kg/min) v=6×D (mm)/10 (Niwt% +10×Nbwt% +5×Tiwt%), the melting speed in the steady-state stage adopts linear reduction along with the increase of the weight of the ingot, the reduction proportion is one percent of the weight increase value of the ingot, meanwhile, the short circuit of the molten drop is controlled to be 6-8 stages, the short circuit frequency of the molten drop is 3-5Hz, and the corresponding arc length process is not more than 8mm; in the heat capping stage, the melting speed is reduced by 0.2kg/min, and when the melting speed reaches 1kg/min, the heat preservation is carried out for 20min, then the power is cut off, and the helium gas is stopped blowing;
step 5: after stopping blowing helium for 60Min, breaking the air and demoulding to obtain the finished product.
The diameter of the electrode E1 in the step 1 is more than or equal to 880mm.
The diameter of the auxiliary electrode which is used in the step 2 and has the same steel type as the hollow electrode E2 during the welding outside the furnace is 5-10mm larger than the diameter of the hollow electrode E2, and an exhaust seam is arranged at the welding position (the joint of the auxiliary electrode and the hollow electrode E2).
And (3) the crystallizer in the step (3) is provided with a half-section type winding water jacket with the pipe diameter of 10mm on the surface of the inner container.
Further, the diameter ratio of the hollow electrode E2 to the crystallizer is more than or equal to 0.85, and the diameter difference value of the hollow electrode E2 and the crystallizer is more than or equal to 12mm.
In the steady-state stage in the step 4, the control level of the short circuit of the molten drops is 6-8, the short circuit frequency of the molten drops is 3-5Hz, and the corresponding arc length process is not more than 8mm.
The diameter of the super-large-specification superalloy prepared by the method is not less than 1000mm, the secondary crystal spacing of the longitudinal secondary slice of the superalloy is less than 0.2mm, and the depth of a molten pool is 300-420mm.
The consumable electrode required by the ultra-large vacuum consumable remelting has large specification, shrinkage cavities and looseness can be generated in the preparation process (vacuum induction or electroslag remelting), and the central area is a concentrated area generated by various segregation, so that the hereditary solidification white spots are generated in the vacuum consumable remelting process. In addition, the high temperature region is located at the center of the consumable electrode and the molten pool during conventional vacuum consumable remelting, which results in a temperature gradient from the center to the edge of the molten pool, so that the molten pool is deepened and narrowed, thereby promoting the generation of segregation. Aiming at the characteristic of the traditional vacuum consumable remelting, the invention creatively adopts a consumable electrode tube penetrating process after high-temperature annealing to obtain the hollow electrode, the ratio of the diameter of the consumable electrode to the diameter of a consumable crystallizer adopted by the technology is not less than 0.85, the diameter difference of the consumable electrode and the consumable crystallizer is not less than 12mm, the hollow diameter of the electrode is not less than 50mm but not more than 20% of the diameter of the electrode (for example, the diameter of the electrode is 1000mm, the diameter of a molybdenum plug for tube penetrating is selected to be 50-200mm specification range), the diameter of an auxiliary electrode of the same steel type welded with the hollow electrode is larger than 5-10mm of the hollow size, and an exhaust gap is reserved. By adopting the design, firstly, the high segregation area of the center heredity of the oversized vacuum consumable remelting electrode is removed, so that the heredity segregation problem is solved; secondly, as the center of the consumable electrode is hollow, a high-temperature area between the electrode and the molten pool is transferred from the center to the radius of the 1/2 cast ingot, the vacuum consumable molten pool becomes shallow and flat, the local solidification time of the pasty area is reduced by more than 20%, and the generation of metallurgical defects such as black spots and the like is effectively controlled; furthermore, as the whole electrode is hollow, and the air exhaust seam is reserved at the upper part, gas (comprising volatile elements such as CO, calcium ions and the like) generated when the electrode is melted in the whole remelting process is exhausted through the hollow channel when volatilized, so that the influence on an electric arc is avoided, and the stability of the whole remelting process is promoted.
Aiming at the adverse effect of CO formed by the reaction of C, O in the vacuum consumable remelting process and Ca ions on the stability of an electric arc, the content of C in the consumable electrode is not more than 0.02wt percent, the content of O is not more than 12ppm, and the partial pressure of CO in the vacuum consumable remelting is not more than 0.1Pa; the Ca content in the electrode is less than 1ppm so as not to affect the arc stability.
Aiming at the characteristic that in the conventional VAR remelting process, due to solidification shrinkage of metal, a shrinkage gap exists between an ingot at the lower part of the surface of a molten pool and a crystallizer, and the heat transfer mode is changed into the characteristic that the heat transfer efficiency is obviously reduced due to radiation heat transfer. Preferably, the invention is further improved on the basis of the conventional helium filling cooling technology, compressed low-temperature liquid helium with the purity of more than 99.999 percent is adopted to replace common bottled helium, the low-temperature high-purity helium is directly filled in a gap between an ingot at the lower part of the surface of a molten pool and a crystallizer after decompression gasification, meanwhile, in the technical aspect of the process, high-flow helium is adopted to properly break the liquid seal of the liquid molten pool, so that the detected vacuum pressure value in the furnace is increased to 50-150Pa, but the total vacuum degree is strictly forbidden to be more than 200Pa, thereby further strengthening the cooling of the molten pool, forming helium plasma through the moderately overflowed helium and electric arc, reducing the thickness of a consumable ingot shell to below 2mm, inhibiting the splash of the molten pool, and further controlling the dirty white spot metallurgical defect caused by falling of the molten pool in the ingot shell in the electric arc.
Aiming at the problem that the smelting process of the vacuum consumable remelting of the oversized ingot is not accurate enough, the invention combines the solidification heat transfer rule of the easily segregated alloy element to obtain: the set value of the melting rate after entering the steady state should be a function of the equivalent of nickel, niobium and titanium and the diameter of the consumable ingot, i.e. the melting rate (kg/min) v=6×d (mm)/10 (Niwt% +10×nbwt% +5×tiwt%), and the melting rate in the steady state stage decreases linearly with the increase of the weight of the ingot by one percent of the increase of the weight of the ingot. Meanwhile, the control level of the selected droplet short circuit is 6-8, the droplet short circuit frequency is 3-5Hz, and the corresponding arc length process is not more than 8mm.
Aiming at the problem of slow speed of the conventional vacuum consumable remelting circulating cooling water, the invention innovatively adopts the surrounding type half-section sleeve to wind the crystallizer liner, and the pipe diameter of the crystallizer liner is 5-10mm, so that the flow rate of the circulating cooling water is obviously improved from the conventional 10-20L/s to not lower than 50L/s under the same water pump power, and the heat efficiency of a molten pool is improved by more than 50%.
According to the invention, through systematic change or optimization of heat input, namely through optimization of a hollow electrode design and a smelting process and physical state and process in a heat output process, namely the optimization design of a crystallizer water pipe and helium cooling, the occurrence rate of black spots and white spot defects in hereditary segregation and remelting resolidification processes is effectively reduced, so that the stable manufacturing of super-large-specification high-temperature alloy ingots with diameters not smaller than 1000mm is realized.
Drawings
FIG. 1 is a transverse low-power golden phase diagram of the product of example 1 of the present invention;
FIG. 2 is a transverse low-power golden phase diagram of the product of example 3 of the present invention;
FIG. 3 is a transverse low-power gold phase diagram (typical black specks) of the product produced in the comparative example;
FIG. 4 is a transverse low-power golden phase diagram (typical white spots) of the product produced in the comparative example.
Detailed Description
Example 1
Preparation of GH4169 consumable spindle with diameter of 1000mm
Step (1): the content of C in GH4169 is controlled to be 0.01wt%, the content of O is 8ppm, the content of Ca is less than 1ppm, the weight of an electrode E1 with the diameter of 880mm is 18t, the electrode E1 is subjected to hot feeding and high-temperature annealing at 1100 ℃, then a molybdenum plug with the diameter of 100mm is selected to perforate the electrode E1, a hollow electrode E2 with the inner diameter of 100mm is obtained, the loosening of a shrinkage cavity area in the center of the electrode is removed together, the hollow electrode E2 is subjected to surface oxide layer removal and flat head by turning, the weight of the hollow electrode E2 is 17t, an auxiliary electrode with the diameter of 110mm is selected to be subjected to out-of-furnace welding, a reserved seam is welded, the width is 10mm, and the electrode is placed into a furnace after weld scar removal.
Step (2): and dismantling the stainless steel outer water jacket of the conventional common crystallizer, mounting a half-section type winding water jacket with the pipe diameter of 10mm on the outer side of the copper crystallizer liner, checking the fitting degree, locking, and then mounting the stainless steel outer water jacket.
Step (3): and (3) preparing before vacuum consumable remelting, hoisting the prepared crystallizer and hollow electrode E2 to a station, opening a cooling water switch, observing that a general large circulating water flowmeter reaches 10L/s, after winding a pipeline flowmeter by more than 50L/s, starting a vacuum pump to pump the vacuum to below 0.1Pa, testing the air leakage rate to be lower than 1Pa/min, opening a compressed helium pipeline to empty air in a capillary pipeline, and closing when the pressure in the furnace is increased to 100 Pa.
Step (4): setting the weight of a molten ingot to be 1t in a vacuum consumable remelting and arcing stage, then switching to a steady state, starting the melting speed to be 5.2kg/min in the steady state, adopting linear reduction along with the increase of the weight of the ingot in the steady state stage, wherein the reduction proportion is one percent of the increase value of the weight of the ingot, setting the melting speed to be 5.05kg/min when the weight of the ingot is 16t, setting the short-circuit control level of the molten drops to be 6 levels in the steady state stage, and setting the short-circuit frequency of the molten drops to be 3Hz; after the steady state starts, the compressed helium pipeline is opened, the flow valve is adjusted to the helium cooling pipeline pressure gauge to 500Pa, then the flow valve is continuously increased, and the flow setting is maintained after the continuous increase of the vacuum degree in the furnace to 100Pa is observed. Then entering a heat-sealing top stage, setting the melting speed reducing rate to be 0.2kg/min, keeping the temperature for 20min when the melting speed reaches 1kg/min, stopping blowing helium, breaking the air and demoulding after 60 min.
After the GH4169 cast ingot produced by the process is forged and hot processed, the cast ingot is inspected by adopting a water immersion flaw detection method, and no black spots and white spots are found by combining with low-power inspection. The secondary crystal spacing inspection of the longitudinal slices of the consumable ingot is less than 0.2mm, and the depth of a molten pool is 300mm. The test result shows that the invention effectively solves the difficult problem of controlling metallurgical defects in the vacuum consumable remelting process of the oversized ingot.
Example 2
Preparation of GH4169 consumable spindle with diameter of 1100mm
Step (1): the content of C in GH4169 is controlled to be 0.01wt%, the content of O is 8ppm, the content of Ca is less than 1ppm, the weight of an electrode E1 with the diameter of 970mm is 19t, the electrode E1 is subjected to hot feeding and high-temperature annealing at 1100 ℃, then a molybdenum plug with the diameter of 105mm is selected to perforate the electrode E1, a hollow electrode E2 with the inner diameter of 105mm is obtained, the loosening of a shrinkage cavity area in the center of the electrode is removed together, the hollow electrode E2 is subjected to surface oxide layer removal and flat head by turning, the weight of the hollow electrode E2 is 18t, an auxiliary electrode with the diameter of 115mm is selected to be subjected to out-of-furnace welding, a reserved seam is welded, the width is 10mm, and the electrode is placed into a furnace after weld scar removal.
Step (2): and dismantling the stainless steel outer water jacket of the conventional common crystallizer, mounting a half-section type winding water jacket with the pipe diameter of 10mm on the outer side of the copper crystallizer liner, checking the fitting degree, locking, and then mounting the stainless steel outer water jacket.
Step (3): and (3) preparing before vacuum consumable remelting, hoisting the prepared crystallizer and hollow electrode E2 to a station, opening a cooling water switch, observing that a general large circulating water flowmeter reaches 10L/s, after winding a pipeline flowmeter above 60L/s, starting a vacuum pump to pump the vacuum to below 0.1Pa, testing the air leakage rate to be lower than 1Pa/min, opening a compressed helium pipeline to empty air in a capillary pipeline, and closing when the pressure in the furnace is increased to 100 Pa.
Step (4): setting the weight of a molten ingot to be 1t in a vacuum consumable remelting and arcing stage, then switching to a steady state, starting the melting speed to be 5.25kg/min in the steady state, adopting linear reduction along with the increase of the weight of the ingot in the steady state stage, wherein the reduction proportion is one percent of the increase value of the weight of the ingot, setting the melting speed to be 5.1kg/min when the weight of the ingot reaches 17t, setting the short-circuit control level of the molten drops to be 6 levels in the steady state stage, and setting the short-circuit frequency of the molten drops to be 3Hz; after the steady state starts, the compressed helium pipeline is opened, the flow valve is adjusted to the helium cooling pipeline pressure gauge to 500Pa, then the flow valve is continuously increased, and the flow setting is maintained after the continuous increase of the vacuum degree in the furnace to 100Pa is observed. Then entering a heat-sealing top stage, setting the melting speed reducing rate to be 0.2kg/min, keeping the temperature for 20min when the melting speed reaches 1kg/min, stopping blowing helium, breaking the air and demoulding after 60 min.
After the GH4169 cast ingot produced by the process is forged and hot processed, the cast ingot is inspected by adopting a water immersion flaw detection method, and no black spots and white spots are found by combining with low-power inspection. The secondary crystal spacing inspection of the longitudinal slices of the consumable ingot is less than 0.2mm, and the depth of a molten pool is 350mm. The test result shows that the invention effectively solves the difficult problem of controlling metallurgical defects in the vacuum consumable remelting process of the oversized ingot.
Example 3
Preparation of GH4738 consumable spindle with diameter of 1200mm
Step (1): the method comprises the steps of controlling the content of C in GH4738 to be 0.02wt%, the content of O to be 12ppm, the content of Ca to be 1ppm, obtaining an electrode E1 with the diameter of 1100mm by vacuum induction casting and electroslag remelting to be 20t, carrying out hot feeding on the electrode E1 and annealing at the high temperature of 1100 ℃, then selecting a molybdenum plug with the diameter of 110mm to perforate the electrode E1, obtaining a hollow electrode E2 with the inner diameter of 110mm, removing black spots and looseness in a shrinkage cavity area at the center of the electrode, removing surface oxide layers and flat heads of the hollow electrode E2 by turning light, carrying out external furnace welding on the hollow electrode E2 with the weight of 19t, selecting an auxiliary electrode with the diameter of 120mm, welding a reserved joint, and filling the hollow electrode E2 into a furnace after removing a weld scar with the width of 8mm.
Step (2): preparing before vacuum consumable remelting, dismantling a stainless steel outer water jacket of the crystallizer, mounting a half-section type winding water jacket with the pipe diameter of 5mm on the outer side of a copper crystallizer liner, checking the fitting degree, locking, and then mounting the stainless steel outer water jacket.
Step (3): hoisting the prepared crystallizer and hollow electrode E2 to a station, opening a cooling water switch, observing that the general circulating water flowmeter reaches 15L/s, after the winding pipeline flowmeter is more than 70L/s, starting a vacuum pump to pump the vacuum to below 0.1Pa, testing the air leakage rate to be lower than 1Pa/min, opening a compressed helium pipeline to empty air in a capillary pipeline, and closing when the pressure in the furnace is increased to 200 Pa.
Step (4): vacuum consumable remelting, setting the weight of a molten cast ingot (a hollow electrode E2) at an arcing stage to be 1t, then switching to a steady state, starting the melting speed at the steady state to be 5.3kg/min, wherein the melting speed at the steady state stage is linearly reduced along with the increase of the weight of the cast ingot, the reduction ratio is one percent of the increase value of the weight of the cast ingot, the melting speed is set to be 5.15kg/min when the weight of the cast ingot is 18t, the short circuit control level of the molten drops at the steady state stage is 8, and the short circuit frequency of the molten drops at the steady state stage is 5Hz; after the steady state starts, the compressed helium pipeline is opened, the flow valve is adjusted to the helium cooling pipeline pressure gauge to 800Pa, then the flow valve is continuously increased, and the flow setting is maintained after the continuous increase of the vacuum degree in the furnace to 150Pa is observed. Then entering a heat-sealing top stage, setting the melting speed reducing rate to be 0.25kg/min until the melting speed reaches 1kg/min, insulating for 20min, stopping power supply, stopping blowing helium, and breaking the air and demoulding after 90 min.
After the GH4738 cast ingot produced by the process is forged and hot processed, the cast ingot is inspected by adopting a water immersion flaw detection method, and no black spots and white spots are found by combining with low-power inspection. The secondary crystal spacing inspection of the longitudinal slices of the consumable ingot is less than 0.3mm, and the depth of a molten pool is 420mm. The test result shows that the invention effectively solves the difficult problem of controlling metallurgical defects in the vacuum consumable remelting process of the oversized ingot.
Comparative example
Preparation of GH4169 consumable spindle with diameter of 1000mm by conventional technique
Production preparation stage: (1) The content of C in GH4169 is controlled to be 0.02wt percent, the content of O is 20ppm, an electrode 18t with the diameter of 880mm is obtained through vacuum induction casting, the electrode is subjected to heat transfer and high-temperature annealing at 1100 ℃, the surface oxide layer is removed through turning light and is flat-headed, the weight of the electrode is 17.6t, an auxiliary electrode with the diameter of 110mm is selected for out-of-furnace welding, and the electrode is filled into a furnace after weld scars are removed. (2) And a conventional crystallizer is adopted, and circulating water circulates in a large loop from bottom to top. (3) Hoisting the crystallizer and the electrode to a station, opening a cooling water switch, observing that the general large circulating water flowmeter reaches 10L/s, starting a vacuum pump to pump the vacuum degree to below 0.1Pa, testing the leakage rate to be lower than 1Pa/min, opening a compressed helium pipeline to empty air in a capillary pipeline, and closing when the pressure in the furnace is increased to 100 Pa. (3) Setting a smelting process, setting the weight of a molten ingot at an arcing stage to be 1t, then switching to a steady state, setting the melting speed to be 4.8kg/min at the steady state, setting the melting speed to be 4.5kg/min when the weight of the ingot is 16t, and controlling the level 3 of a droplet short circuit in the steady state stage, wherein the droplet short circuit frequency is 10Hz; after the steady state begins, the compressed helium pipeline is opened again, the flow valve is adjusted to the pressure gauge of the helium cooling pipeline to 350Pa, and the pressure is adjusted and maintained through the PI flowmeter. Then entering a heat-sealing top stage, setting the melting speed reducing rate to be 0.2kg/min, keeping the temperature for 20min when the melting speed reaches 1kg/min, stopping blowing helium, breaking the air and demoulding after 60 min. And checking the consumable remelting history curve to find that the instantaneous deflation phenomenon caused by the opening of the shrinkage cavity occurs after remelting to the electrode shrinkage cavity area, and continuing until the shrinkage cavity length is finished. After the GH4169 cast ingot produced by the process is forged and hot processed, the cast ingot is inspected by adopting a water immersion flaw detection method, dense dirty white spot metallurgical defects exist at the corresponding part of the gas discharge position, part of defects are solidified white spots, are genetic white spots falling from shrinkage holes, and have a plurality of black spot defects at the steady state and the heat seal top. The secondary crystal spacing of the longitudinal slice of the consumable ingot is checked to be 1-1.5mm, and the depth of a molten pool is 520mm. As shown in fig. 3 and 4, it is demonstrated that the oversized ingot prepared in accordance with the conventional vacuum consumable remelting of the comparative example is difficult to effectively solve the black spot and white spot metallurgical defects.
Claims (6)
1. A method for preparing super-large-specification high-temperature alloy, which is characterized by comprising the following steps:
step 1: controlling the carbon content in the consumable ingot to be not more than 0.02wt%, the oxygen content to be not more than 12ppm, and the calcium content to be less than 1ppm, pouring by vacuum induction to obtain an electrode E1, and carrying out heat transfer and annealing at 1100 ℃ on the electrode E1;
step 2: punching the electrode E1 by using a molybdenum plug with the diameter not less than 50mm and not more than 20% of the diameter of the electrode E1 to obtain a hollow electrode E2, removing a surface oxide layer of the hollow electrode E2 by turning light and flattening, and then welding outside the furnace by using an auxiliary electrode;
step 3: lifting a crystallizer and a hollow electrode E2 to a station in preparation before vacuum consumable remelting, when the circulating water flow of the crystallizer is not lower than 10L/s and the pipeline flow reaches 50L/s, regulating the vacuum degree in the vacuum consumable melting furnace to be lower than 0.1Mpa, and opening a compressed helium pipeline to exhaust air in a capillary pipeline and increase the pressure in the furnace to 50-150pa, wherein the air leakage rate is lower than 1 pa/min;
step 4: the vacuum consumable remelting comprises an arcing stage, a steady-state stage and a heat-seal top stage, wherein the melting speed setting value entering the steady-state stage is a function of the nickel, niobium and titanium contents and the diameter of the consumable ingot, namely the melting speed (kg/min) v=6×D (mm)/10 (Niwt% +10×Nbwt% +5×Tiwt%), meanwhile, the short circuit of the molten drop is controlled to be 6-8 stages, the short circuit frequency of the molten drop is 3-5Hz, and the corresponding arc length process is not more than 8mm; in the heat capping stage, the melting speed is reduced by 0.2kg/min, and when the melting speed reaches 1kg/min, the heat preservation is carried out for 20min, then the power is cut off, and the helium gas is stopped blowing;
step 5: after stopping blowing helium for 60Min, breaking the air and demoulding to obtain the finished product.
2. The method for producing an oversized superalloy according to claim 1 wherein electrode E1 in step 1 has a diameter of at least 880mm.
3. The method for preparing super large specification superalloy according to claim 1, wherein the auxiliary electrode of the same steel type as the hollow electrode E2 used in the welding outside the furnace in step 2 has a diameter 5-10mm larger than the diameter of the hollow electrode E2, and an exhaust slit is provided at the welding site.
4. The method for preparing super-large-sized superalloy according to claim 1, wherein the crystallizer in step 3 has a half-section winding water jacket with a pipe diameter of 10mm on the surface of the inner container.
5. The method for producing an oversized superalloy according to claim 4 wherein the diameter ratio of the hollow electrode E2 to the crystallizer is not less than 0.85 and the difference in diameter is not less than 12mm.
6. An oversized superalloy prepared by the method for preparing an oversized superalloy according to any of claims 1 to 5, wherein the superalloy has a diameter of at least 1000mm and the secondary grain spacing of the longitudinal secondary slices of the superalloy is less than 0.3mm.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117926020A (en) * | 2024-03-20 | 2024-04-26 | 成都先进金属材料产业技术研究院股份有限公司 | High-homogeneity nickel-based superalloy and preparation method thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3469968A (en) * | 1965-10-20 | 1969-09-30 | Allegheny Ludlum Steel | Electroslag melting |
| GB1510909A (en) * | 1976-10-25 | 1978-05-17 | Inst Elektroswarki Patona | Plasma-arc-remelting |
| US5444732A (en) * | 1992-06-11 | 1995-08-22 | The Japan Steel Works | Electrode for electroslag remelting and process of producing alloy using the same |
| CN113172306A (en) * | 2021-04-22 | 2021-07-27 | 西安交通大学 | Hollow electrode wire feeding electric arc additive manufacturing system and method |
| CN114015889A (en) * | 2021-10-19 | 2022-02-08 | 河南中原特钢装备制造有限公司 | Nitrogen-filled electroslag process for hollow billet cavity of nitrogen-containing steel |
-
2023
- 2023-05-23 CN CN202310584224.0A patent/CN116287744B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3469968A (en) * | 1965-10-20 | 1969-09-30 | Allegheny Ludlum Steel | Electroslag melting |
| GB1510909A (en) * | 1976-10-25 | 1978-05-17 | Inst Elektroswarki Patona | Plasma-arc-remelting |
| US5444732A (en) * | 1992-06-11 | 1995-08-22 | The Japan Steel Works | Electrode for electroslag remelting and process of producing alloy using the same |
| CN113172306A (en) * | 2021-04-22 | 2021-07-27 | 西安交通大学 | Hollow electrode wire feeding electric arc additive manufacturing system and method |
| CN114015889A (en) * | 2021-10-19 | 2022-02-08 | 河南中原特钢装备制造有限公司 | Nitrogen-filled electroslag process for hollow billet cavity of nitrogen-containing steel |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117926020A (en) * | 2024-03-20 | 2024-04-26 | 成都先进金属材料产业技术研究院股份有限公司 | High-homogeneity nickel-based superalloy and preparation method thereof |
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