WO2021036225A1 - 一种高铌高温合金大尺寸铸锭的冶炼工艺及高铌高温合金大尺寸铸锭 - Google Patents

一种高铌高温合金大尺寸铸锭的冶炼工艺及高铌高温合金大尺寸铸锭 Download PDF

Info

Publication number
WO2021036225A1
WO2021036225A1 PCT/CN2020/078718 CN2020078718W WO2021036225A1 WO 2021036225 A1 WO2021036225 A1 WO 2021036225A1 CN 2020078718 W CN2020078718 W CN 2020078718W WO 2021036225 A1 WO2021036225 A1 WO 2021036225A1
Authority
WO
WIPO (PCT)
Prior art keywords
consumable
remelting
rate
electroslag
ingot
Prior art date
Application number
PCT/CN2020/078718
Other languages
English (en)
French (fr)
Inventor
黄烁
赵光普
张北江
段然
秦鹤勇
李连鹏
丑英玉
齐超
Original Assignee
北京钢研高纳科技股份有限公司
抚顺特殊钢股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 北京钢研高纳科技股份有限公司, 抚顺特殊钢股份有限公司 filed Critical 北京钢研高纳科技股份有限公司
Priority to EP20771183.9A priority Critical patent/EP4023779A4/en
Priority to US17/033,959 priority patent/US11859262B2/en
Publication of WO2021036225A1 publication Critical patent/WO2021036225A1/zh

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C30/00—Alloys containing less than 50% by weight of each constituent
    • C22C30/02—Alloys containing less than 50% by weight of each constituent containing copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/16—Remelting metals
    • C22B9/18—Electroslag remelting
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/02—Making non-ferrous alloys by melting
    • C22C1/023—Alloys based on nickel
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C22C19/03—Alloys based on nickel or cobalt based on nickel
    • C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
    • C22C19/051—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W
    • C22C19/056—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W with the maximum Cr content being at least 10% but less than 20%
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/002—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working by rapid cooling or quenching; cooling agents used therefor
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/10—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of nickel or cobalt or alloys based thereon
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

Definitions

  • the invention relates to the technical field of high-niobium superalloy large-size ingots, more specifically, it relates to a smelting process for high-niobium superalloy large-size ingots and high-niobium superalloy large-size ingots prepared by using the smelting process .
  • the turbine wheel material of advanced heavy-duty gas turbines above 200MW is gradually upgraded from alloy steel to superalloy.
  • the yield strength of superalloy at 500°C is increased by more than 40%
  • the endurance strength of 100000h at 550°C is increased by more than 300%, which can significantly improve the high-temperature strength and long-term durability of heavy-duty gas turbine wheels, which is conducive to simplifying the structure.
  • the size of the turbine wheel of a heavy-duty gas turbine generally exceeds 2000mm, the weight of forgings required exceeds 10 tons, and the weight of ingots required exceeds 15 tons.
  • the prepared turbine roulette must be reliably serviced for more than 100,000 hours in a service environment for a long time, which puts forward high requirements on the metallurgical quality of the ingot.
  • the triple smelting process of "vacuum induction melting + electroslag remelting + vacuum consumable remelting" is generally used for high-temperature large ingots of more than 10 tons produced in Europe and the United States.
  • the patent US20020170386A1 provides a triple smelting process for large ingots of 718 and other alloys with a diameter of 762 mm or more. During the use of the triple smelting equipment, the diameter of the ingot type and the electrode need to be matched.
  • the patent provides several examples of matching ingot type and electrode.
  • the weight of vacuum induction ingot exceeds 20 tons, and the equipment capacity for vacuum induction furnace and electroslag remelting furnace More demanding.
  • the main technical bottleneck for domestic production of large ingots of high-temperature alloys of more than 15 tons is that there is no vacuum induction melting equipment with a nominal capacity of more than 20 tons, and it is impossible to prepare a single vacuum induction electrode ingot of more than 20 tons.
  • the large-size electroslag ingot is prepared by the method of double-arm exchange electrode remelting, and a series of quality defects such as injection, flow steel, composition fluctuation and inclusions are easily formed during the electrode exchange process. Even through the subsequent high-temperature diffusion annealing and electrode forging, the above-mentioned quality defects cannot be completely eliminated.
  • the first object of the present invention is to provide a smelting process for large-size ingots of high-niobium superalloys, which can effectively solve the large-size ingot diameter or weight of high-niobium superalloys. Segregation aggravates the formation of black spots and white spots, metallurgical defects, steel ingot bursting caused by large thermal stress, and the problem that the weight of the steel ingot cannot be increased due to the tonnage limit of the electrode arm of the electroslag remelting equipment, and the ingot weight can be more than 15 tons.
  • the preparation of large-size ingots of high-niobium superalloys with a diameter of 800mm or more can minimize the formation of black spots and white spots metallurgical defects, reduce the degree of element segregation, and effectively prevent steel ingots from bursting.
  • the second object of the present invention is to provide a large-size ingot of high niobium superalloy produced by the above-mentioned smelting process, the weight of the obtained ingot can reach at least 15 tons, no thermal cracking, and no black spots, white spots and other metallurgical ingots.
  • the present invention provides the following technical solution: a smelting process for large-size ingots of high-niobium superalloys, which includes the following steps:
  • Vacuum induction melting using pure metal raw materials and/or returned materials as raw materials, vacuum induction melting is carried out, and multiple vacuum induction ingots with the same composition are poured;
  • Exchange electroslag remelting use the vacuum induction ingots to make the same number of electroslag electrodes; use all the prepared electroslag electrodes, exchange electroslag remelting under argon protection, after the exchange of electroslag remelting , Cooling, demolding, to obtain electroslag ingots: perform multiple vacuum consumable remelting: perform primary annealing, secondary annealing, forging and drawing the demolded electroslag ingots to a predetermined size to obtain a consumable electrode , Wherein the secondary annealing temperature is higher than the primary annealing temperature; then, using the primary consumable electrode as the starting material, at least two vacuum consumable remelting are performed, and the consumable remelted ingot obtained from each vacuum consumable remelting is used for The consumable electrode to be used for the next vacuum consumable remelting is made, and the diameter of the consumable remelted ingot obtained from each vacuum consumable remelting is increased successively, until the melting rate does not fluctu
  • a conventional tonnage (such as 12 tons) vacuum induction furnace is used to prepare multiple induction ingots with the same composition (this also reduces the weight of a single induction ingot Requirement) to prepare multiple electroslag electrodes, and then adopt electrode exchange remelting to prepare large-tonnage electroslag ingots, and then perform multiple vacuum consumable remelts.
  • one vacuum consumable remelting can improve the electrode
  • the metallurgical quality of the exchange joints can be completely resolved through two or more vacuum consumable remelting, so as to prepare high-quality, metallurgical defect-free high-temperature alloys of at least 15 tons of large-scale self-consumption Consuming ingots.
  • the total weight of multiple vacuum induction ingots should be 125% to 160% of the target weight of the ingot.
  • the Nb content in the raw material is 2.8-5.5 wt.%
  • the Al content is 0.2-1.0 wt.%
  • the Ti content is 0.5-2.0 wt.%.
  • the melting temperature of the raw materials is 1400-1550°C
  • refining is carried out under electromagnetic stirring for 15-120 minutes, and the refining temperature is 1350-1550°C; then cooling for 1-10 hours
  • the mold is demolded to obtain a vacuum induction ingot; the vacuum induction smelting process is repeated many times, and there are many vacuum induction ingots with the same composition.
  • the method of preparing the electroslag electrode is to directly stress-relieve annealing each vacuum induction ingot.
  • the temperature is pre-heated to 600-800°C, and then at a rate of 5-45°C/h
  • the temperature is raised to 800-1000°C and kept for 4 ⁇ 32h, and then cooled to 600 ⁇ 800°C at a rate of 1 ⁇ 35°C/h and kept for 4 ⁇ 32h; then air-cooled and then polished and flat-headed to obtain the electroslag electrode.
  • the diameter of the resulting electroslag electrode should be matched with the diameter of the matching mold of the vacuum consumable electric arc furnace used in the vacuum consumable remelting step, that is, the diameter of the matching mold and the electrode should maintain an appropriate ratio, that is, filling
  • the ratio is about 0.8 to 0.9.
  • This application adopts the above solution to directly stress-relieve and anneal the vacuum induction ingot.
  • It can prevent the temperature from falling into the aging precipitation zone due to air cooling after the ingot is demolded in time to form excessive structural stress;
  • Reasonable heating rate increases the temperature of the steel ingot, aiming at the problem of low thermal conductivity of the superalloy, avoiding large thermal stress inside and outside the steel ingot;
  • keeping the temperature at 800 ⁇ 1000°C for a certain period of time can make the temperature of the steel ingot fully uniform and release the internal stress of solidification ;
  • Fourth, the slow cooling of 1 ⁇ 35°C/h and the heat preservation of 600 ⁇ 800°C for a certain time can effectively prevent the steel ingot from forming greater thermal stress and structural stress again.
  • the slag system used is (CaF 2 -CaO-Al 2 O 3 -TiO 2 ) quaternary slag, (CaF 2 -CaO-Al 2 O 3- TiO 2 )
  • CaF 2 accounts for 60 to 75 wt.%
  • CaO accounts for 10 to 25 wt.%
  • Al 2 O 3 accounts for 10 to 25 wt.%
  • TiO 2 accounts for 1 to 10 wt.%
  • electroslag remelting is stable
  • the state melting rate is controlled at 5 ⁇ 15kg/min, and before each electrode exchange, when the remaining weight of the current electrode is 500kg ⁇ 1000kg, the melting rate is increased to 12 with a slope of 0.5 ⁇ 2kg/min on the basis of the steady state melting rate.
  • the content of TiO 2 in the electroslag is controlled to be 1-10 wt.%, which can solve the problem of the burning loss of the Ti element at the head and tail of the electroslag ingot.
  • the steady-state melting rate of electroslag remelting is controlled to be 5-15kg/min. The subsequent adjustment of the melting rate before and after the electrode exchange can reasonably increase the depth of the molten pool when the electrode is exchanged, which can solve the problem of the exchange electrode.
  • the fluidity of the molten pool is reduced due to the suspension of smelting, which reduces the disturbance of the molten pool caused by the instantaneous embedding of the electrode in the slag pool, and reduces metallurgical quality problems such as inclusions and injection.
  • the demolded electroslag ingot is subjected to primary annealing, secondary annealing, forging and drawing to a predetermined size to obtain a consumable electrode.
  • an annealing is started within 0.5-2h after demolding. Specifically, it is preheated to 300-550°C, held for 12-32h to achieve uniform temperature, and then heated at a rate of 1-25°C/h to 600 ⁇ Hold at 750°C for 4 ⁇ 32h, then heat up to 800 ⁇ 1000°C at a rate of 5 ⁇ 35°C/h and keep it at 800 ⁇ 1000°C for 4 ⁇ 32h, then cool to 550 ⁇ 750°C at a rate of 1 ⁇ 35°C/h and keep it at 4 ⁇ 32h, then Air cooling
  • the electroslag ingot after secondary annealing it is heated to 1100 ⁇ 1180°C before forging, and the heating time before forging is 4 ⁇ 12h.
  • the free forging adopts a fast forging machine of more than 3000 tons to draw the length in one direction, and each pass is pressed down on one side.
  • the amount is controlled at 5 ⁇ 30mm, and the final forging temperature is 850 ⁇ 1000°C;
  • the head and tail are flattened, and a consumable electrode is obtained.
  • the diameter of the primary consumable electrode should be matched with the diameter of the matching mold of the vacuum consumable arc furnace used in the primary vacuum consumable remelting.
  • the reason for adopting the above technical solution is that the obtained high-niobium superalloy ingots with a diameter of 1000mm or more in the electroslag ingots have great thermal stress during the solidification process and are very easy to burst; due to the reasonable requirements for consumable electrodes and corresponding crystallizers Filling ratio, the large-sized electroslag ingot cannot be directly used for one-time consumable remelting, and free forging is needed to reduce the diameter, for example, it can be 800-900mm; but because the diameter of the electroslag ingot is too large, solidification segregation Very serious, there are severe dendrite element segregation and low melting point phase between dendrites, and the thermoplasticity is extremely poor.
  • the application after the electroslag remelting is completed, is cooled by water in the water-cooled crystallizer in the adopted electroslag remelting furnace for 2-10 hours.
  • an annealing is started within 0.5-2h after demolding.
  • the thermal stress formed by the temperature gradient during the solidification of the electroslag ingot can be released, and at the same time, the over-aging treatment is used to coarsen the strengthening phase to avoid the formation of structural stress, thereby inhibiting the direct explosion of the large-size superalloy electroslag ingot after demolding.
  • the electroslag ingots In order to improve the thermal plasticity of high-niobium superalloy electroslag ingots with a diameter of 800mm or more, the electroslag ingots should be subjected to secondary annealing after annealing, that is, high-temperature diffusion annealing. In order to avoid excessive thermal stress, the heating rate must be strictly controlled. Therefore, the electroslag ingot is kept at a temperature below 550-750°C for 4-24 hours, and then the temperature is raised to 800-1000°C at a rate of 5-35°C/h.
  • the first vacuum consumable remelting and the second vacuum consumable remelting are performed as follows:
  • the steady-state melting rate is controlled to 3.5 ⁇ 7.5kg/min; after 800 ⁇ 2000kg smelting is started, helium cooling is started; after the remaining 1500 ⁇ 5000kg, the current is reduced to adjust the melting rate to 3.0 ⁇ 7.0kg/min; After the remaining 200 ⁇ 1000kg, heat sealing is started to produce a consumable remelted ingot;
  • the primary consumable remelting ingot is first polished and the head and tail are flattened to obtain a secondary consumable electrode with a diameter that matches the diameter of the mold used in the secondary vacuum consumable remelting;
  • the steady-state melting rate is controlled at 4.0 ⁇ 8.5kg/min; after starting to melt 1000 ⁇ 3000kg, it is cooled by helium gas; after the remaining 2000 ⁇ 5500kg, the current is reduced to adjust the melting rate to 3.0 ⁇ 7.5kg /min; After remaining 250 ⁇ 1500kg, start heat sealing;
  • vacuum cooling for 1 ⁇ 8h, and then start stress relief annealing within 2h; during annealing, preheat to 300 ⁇ 750°C, keep it for 4 ⁇ 32h to achieve uniform temperature, and then use 5 ⁇ 50°C/
  • the temperature is raised to 800-1000°C at a rate of h, and the temperature is kept for 4 to 32 hours, and then cooled to 550-750°C at a rate of 1 to 35°C/h, and the temperature is kept for 4 to 32 hours, and then air-cooled.
  • the volume of the ingot will shrink during solidification, and there will be a gap with the mold wall.
  • the cooling water of the steel ingot and the outer wall of the mold cannot directly contact the cooling water to achieve heat dissipation.
  • Helium conducts heat; in the early stage of smelting, the steel ingot can dissipate heat through the bottom and the mold.
  • the bottom heat dissipation is limited. For this reason, it is necessary to pass in a proper amount of helium after a certain stage of smelting.
  • this application will turn the primary consumable remelting ingots, flat head and tail to prepare secondary consumable electrodes, and then perform secondary consumable remelting. Since the diameter of the steel ingot after the secondary consumable remelting exceeds 800mm, there will be great thermal stress, so after the secondary consumable remelting is completed, vacuum cooling is required, and then the stress relief annealing is started within 2h to avoid the steel ingot. After demolding, it bursts.
  • annealing it should be preheated to 300 ⁇ 750°C and kept for 4 ⁇ 32h to achieve uniform temperature, then at a rate of 5 ⁇ 50°C/h to 800 ⁇ 1000°C and kept for 4 ⁇ 32h, and then at 1 ⁇ 35°C Cooling to 550 ⁇ 750°C for 4 ⁇ 32h at a rate of /h, and then air cooling.
  • the subsequent use of this method can release the thermal stress formed by the temperature gradient during the solidification of the consumable remelted ingot.
  • the over-aging treatment is used to make The strengthening phase is coarsened to avoid the formation of structural stress, thereby inhibiting the direct explosion of large-size superalloy electroslag ingots after demolding.
  • the obtained secondary consumable remelted ingot is used to prepare the primary consumable electrode, Perform the same primary annealing, secondary annealing, forging and elongation to prepare the consumable electrode for the next vacuum consumable remelting, and then repeat the secondary consumable remelting process again.
  • the diameter of the consumable electrode to be used in the next vacuum consumable remelting should be matched with the diameter of the matching mold of the vacuum consumable arc furnace used in the next vacuum consumable remelting.
  • the high-niobium high-temperature alloy large-size ingots prepared by the above-mentioned smelting process provided by the present invention are specifically 706 alloy with a diameter of more than 800mm. According to mass percentage, the chemical composition of the 706 alloy is:
  • the high-niobium superalloy large-size ingots prepared by the above-mentioned smelting process provided by the present invention are specifically 718 alloy with a diameter of more than 800mm. According to mass percentage, the chemical composition of the 718 alloy is:
  • the electroslag furnace with the limited tonnage of the electrode arm can be used to prepare 20-ton high-temperature alloy electroslag ingots by the method of exchange electroslag remelting;
  • the electroslag ingot prepared by exchange electroslag remelting is subjected to high temperature diffusion annealing to obtain a certain degree of thermoplasticity, and then free forging is used to open the billet to prepare a consumable electrode with a suitable diameter, which can significantly improve the melting stability of a consumable remelting process.
  • Sex
  • the secondary consumable electrode prepared by the primary consumable remelting steel ingot is used for the secondary consumable remelting. If necessary, further consumable remelting is carried out multiple times, which can effectively solve the electroslag exchange during the electroslag remelting process.
  • Metallurgical defects such as inclusions at the ingot exchange electrode joints are used to prepare high-niobium superalloy consumable ingots with a diameter of 800mm or more and an ingot weight of more than 15 tons without metallurgical defects.
  • This embodiment is used to illustrate the method of preparing 706 alloy (a consumable ingot with a diameter of 1050 mm).
  • Target 706 alloy composition (by mass percentage):
  • the specific preparation method is as follows:
  • Vacuum induction smelting According to the designed alloy composition requirements, 50% of the return material is weighed according to the required elements of the alloy per unit weight, and the rest is made of new metal raw materials. Using a 12-ton vacuum induction furnace, the upper limit of the melting temperature is 1550°C. After melting, the composition of the molten steel is detected. By adding new metal, the Nb content in the molten steel is controlled to be about 3.02wt.%, the Ti content is about 1.80wt.%, and the Al content. About 0.30wt.%, according to the amount of added metal material, refining for 15-30 minutes under electromagnetic stirring, the refining temperature is 1350°C, and the tapping temperature is 1400°C.
  • the furnace After pouring the steel, the furnace is cooled for 4 hours and then demolded to obtain a 12-ton vacuum electrode ingot with a diameter of 820mm, which is then directly annealed.
  • the annealing furnace is preheated to 600°C, and then heated at a rate of 5°C/h to 800°C for 24 hours, and then cooled at a rate of 1°C/h to 600°C for 10 hours, and then air-cooled.
  • the annealed vacuum induction ingot car/polishing, flat head and tail are used to prepare the electroslag electrode.
  • Electroslag remelting The diameter of the crystallizer is 1100mm, and the slag system is (CaF 2 -CaO-Al 2 O 3 -TiO 2 ) quaternary slag.
  • the specific composition is: CaF 2 60%, CaO 10%, Al 2 O 3 25% , TiO 2 10%.
  • the steady-state melting rate is 15kg/min, and Ar gas protection at a pressure of 0.2bar is introduced during the melting process to prevent the molten steel from contacting oxygen and nitrogen in the air during the melting process. Before the electrode exchange, when the remaining weight is 800kg, adjust the input power and voltage to increase the melting rate. On the basis of the steady-state melting rate, increase the melting rate with a slope of 1.05kg/min.
  • the electroslag electrode When it reaches 25kg/min, it will remain stable until the electroslag electrode is exchanged. .
  • the electrode exchange process maintains the smelting parameters before the exchange, and the exchange time cannot exceed 2 min.
  • the second electrode melts 100kg, the melting rate is increased by adjusting the input power and voltage, and the melting rate is reduced to 10kg/min at a slope of 0.50kg/min. After the second electrode remains 200kg, the heat sealing starts.
  • the water-cooled crystallizer in the furnace is cooled by water for 4 hours, and within 0.5 hours after demolding, it is transferred to the annealing furnace for stress relief annealing.
  • the annealing furnace should be pre-heated to 300°C, kept at 300°C for 12h, then at a rate of 5°C/h to 600°C for 4h, then at a rate of 10°C/h to 800°C for 5h, and then at 5°C/h Cool down to 600°C for 12 hours at a rate of h, then cool in air.
  • High temperature diffusion annealing of electroslag ingots install the furnace at a temperature below 550°C for 4 hours, then heat up to 800°C at a rate of 10°C/h, then heat up to 1050°C at a rate of 5°C/h, hold for 4 hours, and then heat at 5°C/h
  • the temperature was raised to 1150°C for 24 hours at a rate of h, and then cooled to 800°C for 32 hours at a rate of 5°C/h, and then air-cooled.
  • Electrode forging The heating temperature before forging of the electroslag ingot with a diameter of 1100mm is 1100°C, and the heating time before forging is 4h.
  • the free forging adopts a 3500 ton fast forging machine to draw length in one direction, and the unilateral reduction of each pass is controlled to 25mm, the final forging temperature is 850°C, and the final forging, turning, and flat head and tail are prepared to a diameter of 820mm. Extremely, used for a vacuum consumable remelting.
  • One-time vacuum consumable remelting The diameter of the crystallizer is 920mm, the consumable remelting is controlled by the melting rate, and the steady-state melting rate is controlled to 3.5kg/min; the helium cooling is started after 800kg of smelting; after the remaining 1500kg, the current is reduced to adjust the melting The speed reaches 3.0kg/min; after the remaining 200kg, the heat sealing is started, and the heat sealing is controlled by the current.
  • the primary consumable remelting ingot is machined and flat-headed to a diameter of 900mm, which is used for secondary vacuum consumable remelting.
  • Secondary vacuum self-consumption remelting 1050mm is used for the crystallizer, the melting is controlled by the melting rate, and the steady-state melting rate is controlled to 4.0kg/min; the helium cooling is started after the smelting of 1000kg; after the remaining 2000kg, the current is reduced to adjust the melting rate to 3.0 kg/min; after the remaining 250kg, the heat sealing is started, and the heat sealing is controlled by the current.
  • the secondary vacuum consumable remelting After the secondary vacuum consumable remelting is completed, it is vacuum cooled for 3 hours, and then the void is transferred to the annealing furnace for stress relief annealing within 2 hours to avoid the steel ingot from bursting after demolding.
  • the annealing furnace should be preheated to 300°C for 4 hours to achieve uniform temperature, then at a rate of 5°C/h to 800°C for 5 hours, then at a rate of 5°C/h to 550°C for 5 hours, and then air-cooled.
  • Test result The trial-produced 1050mm consumable ingot of 706 alloy weighs 15.5 tons, and there is no hot cracking, and no metallurgical defects such as black spots and white spots.
  • the composition test on the head and tail of the steel ingot showed that the Al and Ti elements at the head and tail have no obvious burning loss.
  • the Al element is 0.27% at the head and 0.24% at the tail.
  • the Ti element is 1.68% at the head and 1.78% at the tail.
  • the bars were inspected by non-destructive flaw detection and found that there was no abnormal signal at the electroslag remelting joints, indicating that the secondary vacuum consumable remelting can effectively solve the metallurgical quality problems at the 706 alloy electroslag joints.
  • This embodiment is used to illustrate the method of preparing 706 alloy (a consumable ingot with a diameter of 1050 mm).
  • Target 706 alloy composition (by mass percentage):
  • the specific preparation method is as follows:
  • Vacuum induction smelting According to the designed alloy composition requirements, 50% of the return material is weighed according to the required elements of the alloy per unit weight, and the rest is made of new metal raw materials. A 12-ton vacuum induction furnace is used. The upper limit of the melting temperature is 1550°C. After melting, the composition of the molten steel is detected. By adding new metal, the content of Nb in the molten steel is controlled to be about 2.90wt.%, the content of Ti is about 1.62wt.%, and the content of Al. About 0.20wt.%, refining for 40 minutes under electromagnetic stirring, the refining temperature is 1480°C, and the tapping temperature is 1500°C. The steel was poured in two times.
  • the furnace was cooled for 4 hours and then demolded to obtain two 12-ton consumable ingots with a diameter of 820mm, which were then directly annealed.
  • the annealing furnace is preheated to 650°C, and then heated to 900°C at a rate of 25°C/h for 24 hours, and then cooled to 700°C at a rate of 15°C/h for 10 hours, and then air-cooled.
  • the annealed vacuum induction ingots are turned and flattened to prepare electroslag electrodes.
  • Electroslag remelting The diameter of the crystallizer is 1100mm, and the slag system is (CaF 2 -CaO-Al 2 O 3 -TiO 2 ) quaternary slag.
  • the specific composition is: CaF 2 64%, CaO 15%, Al 2 O 3 15 %, TiO 2 6%.
  • the steady-state melting rate is 10kg/min, and Ar gas protection at 0.2bar pressure is introduced during the smelting process to prevent the molten steel from contacting oxygen and nitrogen in the air during the smelting process.
  • Ar gas protection at 0.2bar pressure is introduced during the smelting process to prevent the molten steel from contacting oxygen and nitrogen in the air during the smelting process.
  • the remaining weight is 500kg, adjust the input power and voltage to increase the melting rate.
  • the electroslag electrode When it reaches 15kg/min, it will remain stable until the electroslag electrode is exchanged. .
  • the electrode exchange process maintains the smelting parameters before the exchange, and the exchange time cannot exceed 2 min.
  • the second electrode melts 200kg, the melting rate is increased by adjusting the input power and voltage, and the melting rate is reduced to 10kg/min at a slope of 0.75kg/min.
  • the second electrode When the second electrode is left with 500kg, the heat sealing starts.
  • the water-cooled crystallizer in the furnace is cooled by water for 4 hours, and within 0.5 hours after demolding, it is transferred to the annealing furnace for stress relief annealing.
  • the annealing furnace should be preheated to 450°C, kept at 450°C for 24h, then at a rate of 15°C/h to 650°C for 4h, then at a rate of 25°C/h to 950°C for 12h, and then at 15°C/h Cool down to 600°C for 12 hours at a rate of h, then cool in air.
  • High temperature diffusion annealing of electroslag ingots install the furnace at a temperature below 550°C for 4 hours, then heat up to 950°C at a rate of 10°C/h, then heat up to 1100°C at a rate of 15°C/h, hold for 12 hours, and then at 20°C/h The temperature was raised to 1190°C for 48 hours at a rate of h, and then cooled to 850°C for 24 hours at a rate of 15°C/h, and then air-cooled.
  • Electrode forging The heating temperature before forging of the electroslag ingot with a diameter of 1100mm is 1150°C, and the heating time before forging is 10h.
  • the free forging adopts a 3500 ton fast forging machine to draw length in one direction, and the unilateral reduction of each pass is controlled to 25mm, and the final forging temperature is 900°C.
  • the final forging, turning, and flat head and tail are prepared to a diameter of 820mm. Extremely, used for a vacuum consumable remelting.
  • One-time vacuum consumable remelting The diameter of the crystallizer is 920mm, and the consumable remelting is controlled by the melting rate.
  • the steady-state melting rate is controlled at 5.5kg/min; the helium cooling is started after the smelting of 1000kg; the current is reduced after the remaining 2000kg to adjust the melting The speed reaches 4.0kg/min; after the remaining 500kg, the heat sealing is started, and the heat sealing is controlled by the current.
  • the primary consumable remelting ingot is machined and flat-headed to a diameter of 900mm, which is used for secondary vacuum consumable remelting.
  • Secondary vacuum self-consumption remelting 1050mm crystallizer is selected, and the melting is controlled by the melting rate, and the steady-state melting rate is controlled to 6.5kg/min; the helium cooling is started after 1500kg is melted; the current is reduced after the remaining 2500kg to adjust the melting rate to 6.0 kg/min; after the remaining 800kg, the heat sealing is started, and the heat sealing is controlled by the current.
  • the secondary vacuum consumable remelting After the secondary vacuum consumable remelting is completed, it is vacuum cooled for 3 hours, and then the void is transferred to the annealing furnace for stress relief annealing within 2 hours to avoid the steel ingot from bursting after demolding.
  • the annealing furnace should be preheated to 450°C for 8 hours to achieve uniform temperature, and then heated at a rate of 10°C/h to 850°C for 24 hours, and then cooled at a rate of 15°C/h to 600°C for 12 hours, and then air-cooled.
  • High temperature diffusion annealing of secondary vacuum consumable ingots The secondary consumable ingots are placed in a furnace at a temperature below 550°C for 4 hours, and then heated to 950°C at a rate of 10°C/h, and then heated to 1100 at a rate of 15°C/h Incubate at °C for 12h, then heat up to 1190°C at a rate of 20°C/h for 48h, then cool to 850°C at a rate of 15°C/h for 24h, and then cool in air.
  • Electrode forging The heating temperature before forging of the consumable ingot with a diameter of 1050mm is 1150°C, and the heating time before forging is 10h. Free forging adopts 3500 ton fast forging machine to draw length in one direction, the unilateral reduction of each pass is controlled to be 25mm, the final forging temperature is 900°C, and the final forging, turning, and flat head and tail are prepared to a diameter of 900mm three times. Pole, used for three vacuum consumable remelting.
  • Three vacuum self-consumption remelting 1050mm mould is selected, melting is controlled by melting rate, steady-state melting rate is controlled at 6.5kg/min; helium cooling is started after 1500kg smelting; after 2500kg, the current is reduced and the melting rate is adjusted to 6.0kg /min; After the remaining 800kg, the heat sealing is started, and the heat sealing is controlled by the current.
  • the secondary vacuum consumable remelting After the secondary vacuum consumable remelting is completed, it is vacuum cooled for 3 hours, and then the void is transferred to the annealing furnace for stress relief annealing within 2 hours to avoid the steel ingot from bursting after demolding.
  • the annealing furnace should be preheated to 450°C for 8 hours to achieve uniform temperature, and then heated at a rate of 10°C/h to 850°C for 24 hours, and then cooled at a rate of 15°C/h to 600°C for 12 hours, and then air-cooled.
  • Test result The trial-produced 1050mm consumable ingot of 706 alloy weighs 16.2 tons, and there is no hot cracking, and no black spots, white spots and other metallurgical defects.
  • the composition test on the head and tail of the steel ingots shows that there is no obvious burning loss of Al and Ti elements at the head and tail.
  • the Al element is 0.17% for the head and 0.12% for the tail.
  • the Ti element is 1.65% for the head and 1.47 for the tail. .
  • After the three-time consumable remelted ingot with a diameter of 1050mm is homogenized at high temperature and diffused and annealed, it is arranged for forging after polishing to prepare forged bars.
  • This embodiment is used to illustrate the method of preparing 718 alloy (a consumable ingot with a diameter of 1050 mm).
  • the target 718 alloy composition is (by mass percentage):
  • the specific preparation method is as follows:
  • Vacuum induction smelting According to the designed alloy composition requirements, 40% of the return material is weighed according to the required elements of the alloy per unit weight, and the rest is made of new metal raw materials. Using a 12-ton vacuum induction furnace, the upper limit of the melting temperature is 1550°C. After melting, the composition of the molten steel is detected. By adding new metal, the Nb content in the molten steel is controlled to be about 5.08wt.%, the Ti content is about 0.97wt.%, and the Al content. About 0.60wt.%, refining for 40 minutes under electromagnetic stirring, the refining temperature is 1480°C, and the tapping temperature is 1500°C. The steel is poured in two times.
  • the furnace is cooled for 6 hours and then demolded to obtain two 12-ton consumable ingots with a diameter of 820mm, which are then directly annealed.
  • the annealing furnace is preheated to 800°C, then heated at a rate of 45°C/h to 1000°C for 32 hours, and then cooled at a rate of 35°C/h to 780°C for 32 hours, and then air-cooled.
  • the annealed vacuum induction ingots are turned and flattened to prepare electroslag electrodes.
  • Electroslag remelting The diameter of the crystallizer is 1100mm, and the slag system is (CaF 2 -CaO-Al 2 O 3 -TiO 2 ) quaternary slag.
  • the specific composition is: CaF 2 75%, CaO 25%, Al 2 O 3 10% , TiO 2 1%.
  • the steady-state melting rate is 5kg/min, and Ar gas protection at 0.2bar pressure is introduced during the smelting process to prevent the molten steel from contacting oxygen and nitrogen in the air during the smelting process. Before the electrode exchange, when the remaining weight is 1000kg, adjust the input power and voltage to increase the melting rate.
  • the melting rate On the basis of the steady-state melting rate, increase the melting rate with a slope of 2kg/min to 12kg/min and keep it stable until the electroslag electrode is exchanged.
  • the electrode exchange process maintains the smelting parameters before the exchange, and the exchange time cannot exceed 2 min.
  • the melting rate is increased by adjusting the input power and voltage, and the melting rate is reduced to 15kg/min at a slope of 2kg/min.
  • the second electrode remains 600kg, the heat sealing starts.
  • the electroslag remelting After the electroslag remelting is completed, it should be cooled by passing water in a water-cooled crystallizer in the furnace for 4 hours, and transferred to the annealing furnace for stress relief annealing within 1 hour after demolding.
  • the annealing furnace should be preheated to 550°C, kept at 550°C for 32h, then at a rate of 25°C/h to 750°C for 4h, then at a rate of 30°C/h to 1000°C for 32h, and then at 35°C/h It is cooled to 750°C for 32 hours at a rate of h, and then air-cooled.
  • High temperature diffusion annealing of electroslag ingots install the furnace at a temperature below 550°C for 4 hours, then heat up to 1000°C at a rate of 5°C/h, then heat up to 1150°C at a rate of 25°C/h, hold for 32 hours, and then at 25°C/h The temperature was raised to 1250°C for 72 hours at a rate of h, and then cooled to 950°C for 32 hours at a rate of 35°C/h, and then air-cooled.
  • Electrode forging The heating temperature before forging of the electroslag ingot with a diameter of 1100mm is 1150°C, and the heating time before forging is 12h.
  • the free forging adopts a 3500 ton fast forging machine for unidirectional drawing.
  • the unilateral reduction of each pass is controlled to 25mm, and the final forging temperature is 1000°C.
  • the final forging, turning, and flat head and tail are prepared to a diameter of 820mm. Extremely, used for a vacuum consumable remelting.
  • One-time vacuum consumable remelting the diameter of the crystallizer is 920mm, the consumable remelting is controlled by the melting rate, and the steady-state melting rate is controlled to 7.5kg/min; the helium cooling is started after 2000kg of smelting; the current is reduced after the remaining 1000kg to adjust the melting The speed reaches 7.0kg/min; the heat sealing is started after the remaining 1000kg, and the heat sealing is controlled by the current.
  • the primary consumable remelting ingot is machined and flat-headed to a diameter of 900mm, which is used for secondary vacuum consumable remelting.
  • Secondary vacuum self-consumption remelting 1050mm is selected for the crystallizer, the melting is controlled by the melting rate, and the steady-state melting rate is controlled at 8.5kg/min; after 3000kg of smelting starts, helium cooling is started; after the remaining 5500kg, the current is reduced to adjust the melting rate to 7.5 kg/min; after the remaining 1500kg, the heat sealing is started, and the heat sealing is controlled by the current.
  • the secondary vacuum consumable remelting After the secondary vacuum consumable remelting is completed, it is vacuum cooled for 3 hours, and then the void is transferred to the annealing furnace for stress relief annealing within 2 hours to avoid the steel ingot from bursting after demolding.
  • the annealing furnace should be pre-heated to 750°C for 32 hours to achieve uniform temperature, then at a rate of 50°C/h to 1000°C for 32 hours, then at a rate of 35°C/h to 750°C for 32 hours, and then air-cooled.
  • Test result The trial-produced 1050mm consumable ingot of 718 alloy weighs 15 tons. There is no hot cracking and no metallurgical defects such as black spots and white spots.
  • the composition test on the head and tail of the steel ingot showed that the Al and Ti elements at the head and tail have no obvious burning loss, the Al element is 0.60% at the head and 0.48% at the tail, and the Ti element is 0.87% at the head and 0.98% at the tail.
  • Comparative Example 1 is used to illustrate the preparation method of 706 alloy (a consumable ingot with a diameter of 920 mm) using a triple preparation process.
  • the target 706 alloy composition is the same as the 706 alloy composition of Example 1 (by mass percentage):
  • the specific preparation method is as follows:
  • Vacuum induction smelting According to the designed alloy composition requirements, 40% of the return material is weighed according to the required elements of the alloy per unit weight, and the rest is made of new metal raw materials. A 12-ton vacuum induction furnace is used to prepare two 12-ton consumable ingots with a diameter of 820mm. The upper melting temperature is 1550°C. After melting, the composition of the molten steel is detected. By adding new metal, the Nb content in the molten steel is controlled to be about 3.10wt.%. , Ti content is about 1.82wt.%, Al content is about 0.35wt.%, electromagnetic stirring is used for 40 minutes; the refining temperature is 1480°C, and the tapping temperature is 1500°C.
  • the furnace After pouring the steel, the furnace is cooled for 4 hours and then demoulded, and then directly subjected to annealing treatment.
  • the annealing furnace is preheated to 650°C, and then heated to 900°C at a rate of 25°C/h for 24 hours, and then cooled to 600°C at a rate of 15°C/h for 10 hours, and then air-cooled.
  • the annealed vacuum induction ingots are turned, and the ends are flattened to prepare electroslag electrodes.
  • Electroslag remelting The diameter of the crystallizer is 1100mm, and the slag system is (CaF 2 -CaO-Al 2 O 3 -TiO 2 ) quaternary slag.
  • the specific composition is: CaF 2 70%, CaO 15% , Al 2 O 3 15% , TiO 2 10%.
  • the steady-state melting rate is 10kg/min, and Ar gas protection at 0.2bar pressure is introduced during the smelting process to prevent the molten steel from contacting oxygen and nitrogen in the air during the smelting process. Before electrode exchange, when the remaining weight is 600kg, adjust the input power and voltage to increase the melting rate. On the basis of the steady-state melting rate, increase the melting rate with a slope of 0.55kg/min.
  • the electroslag electrode When it reaches 15kg/min, it will remain stable until the electroslag electrode is exchanged. .
  • the electrode exchange process maintains the smelting parameters before the exchange, and the exchange time cannot exceed 2 min.
  • the second electrode melts 200kg, the melting rate is increased by adjusting the input power and voltage, and the melting rate is reduced to 10kg/min at a slope of 0.75kg/min.
  • the second electrode When the second electrode is left with 500kg, the heat sealing starts.
  • the electroslag remelting After the electroslag remelting is completed, it should be cooled by passing water in a water-cooled crystallizer in the furnace for 4 hours, and transferred to the annealing furnace for stress relief annealing within 0.5 hours after demolding.
  • the annealing furnace should be preheated to 450°C, kept at 450°C for 24h, then at a rate of 15°C/h to 650°C for 4h, then at a rate of 25°C/h to 950°C for 12h, and then at 15°C/h Cool down to 600°C for 12 hours at a rate of h, then cool in air.
  • High temperature diffusion annealing of electroslag ingots install the furnace at a temperature below 550°C for 4 hours, then heat up to 950°C at a rate of 10°C/h, then heat up to 1100°C at a rate of 15°C/h, hold for 12 hours, and then at 20°C/h The temperature was raised to 1190°C for 48 hours at a rate of h, and then cooled to 850°C for 24 hours at a rate of 15°C/h, and then air-cooled.
  • Electrode forging The heating temperature before forging of the electroslag ingot with a diameter of 1100mm is 1150°C, and the heating time before forging is 10h.
  • the free forging adopts a 3500 ton fast forging machine to draw the length in one direction.
  • the unilateral reduction of each pass is controlled to 25mm, and the final forging temperature is 900°C.
  • the consumable electrode with a diameter of 820mm is finally prepared by forging, turning, and flat head. .
  • Self-consumable remelting The diameter of the crystallizer is 920mm, and the self-consumable remelting is controlled by the melting rate.
  • the steady-state melting rate is controlled at 5.5kg/min; the helium cooling is started after the smelting of 1000kg; after the remaining 2000kg, the current is reduced to adjust the melting rate to 4.0kg/min; After the remaining 500kg, the heat sealing is started, and the heat sealing is controlled by the current.
  • the consumable remelting After the consumable remelting is completed, it is cooled in vacuum for 3 hours, and then the void is transferred to the annealing furnace for stress relief annealing within 2 hours to prevent the ingot from bursting after demoulding.
  • the annealing furnace should be preheated to 450°C for 8 hours to achieve uniform temperature, and then heated at a rate of 10°C/h to 850°C for 24 hours, and then cooled at a rate of 15°C/h to 600°C for 12 hours, and then air-cooled.
  • Test results 706 alloy 920mm consumable ingots trial-produced by the triple smelting process, weighing 15 tons, and no hot cracking; the composition test on the head and tail of the steel ingot, the test results show that the head and tail Al and Ti elements are obviously burned. The element is 0.29% in the head and 0.19% in the tail, and the Ti element is 1.62% in the head and 1.80% in the tail.
  • the secondary consumable ingot with a diameter of 1050mm is homogenized at high temperature and diffused and annealed, it is polished and forged to prepare forged bars. The bars were inspected by non-destructive flaw detection, and abnormal signals were found at the electroslag remelting joints, and an obvious black spot defect was found at the joints after anatomy.
  • Comparative example 2 706 alloy consumable ingot with a diameter of 1050mm
  • Comparative Example 1 is used to illustrate the preparation method of 706 alloy (a consumable ingot with a diameter of 1050 mm) using a triple preparation process.
  • the target 706 alloy composition is the same as the 706 alloy composition of Example 2 (by mass percentage):
  • the specific preparation method is as follows:
  • Vacuum induction smelting According to the designed alloy composition requirements, 50% of the return material is weighed according to the required elements of the alloy per unit weight, and the rest is made of new metal raw materials. A 12-ton vacuum induction furnace is used to prepare two 12-ton consumable ingots with a diameter of 820mm. The upper melting temperature is 1550°C. After melting, the content of Nb in the molten steel is about 3.10wt.%, the content of Ti is about 1.72wt.%, and Al. The content is about 0.30wt.%, using electromagnetic stirring for 40 minutes; the refining temperature is 1480°C, and the tapping temperature is 1500°C.
  • the furnace After pouring the steel, the furnace is cooled for 4 hours and then demoulded, and then directly subjected to annealing treatment.
  • the annealing furnace is preheated to 650°C, and then heated to 900°C at a rate of 25°C/h for 24 hours, and then cooled to 600°C at a rate of 15°C/h for 10 hours, and then air-cooled.
  • the annealed vacuum induction ingots are turned, and the ends are flattened to prepare electroslag electrodes.
  • ESR 1100mm diameter mold selection, selection based slag (CaF 2 -CaO-A l2 O3 -TiO 2) four yuan slag, particularly consisting of: CaF 2 64%, CaO15% , Al 2 O 3 15%, TiO 2 6%.
  • the steady-state melting rate is 10kg/min, and Ar gas protection at 0.2bar pressure is introduced during the smelting process to prevent the molten steel from contacting oxygen and nitrogen in the air during the smelting process.
  • Ar gas protection at 0.2bar pressure is introduced during the smelting process to prevent the molten steel from contacting oxygen and nitrogen in the air during the smelting process.
  • the remaining weight is 600kg, adjust the input power and voltage to increase the melting rate.
  • the electroslag electrode When it reaches 15kg/min, it will remain stable until the electroslag electrode is exchanged. .
  • the electrode exchange process maintains the smelting parameters before the exchange, and the exchange time cannot exceed 2 min.
  • the second electrode melts 200kg, the melting rate is increased by adjusting the input power and voltage, and the melting rate is reduced to 10kg/min at a slope of 0.75kg/min.
  • the second electrode When the second electrode is left with 500kg, the heat sealing starts.
  • the electroslag remelting After the electroslag remelting is completed, it should be cooled by passing water in a water-cooled crystallizer in the furnace for 4 hours, and transferred to the annealing furnace for stress relief annealing within 0.5 hours after demolding.
  • the annealing furnace should be preheated to 450°C, kept at 450°C for 24h, then at a rate of 15°C/h to 650°C for 4h, then at a rate of 25°C/h to 950°C for 12h, and then at 15°C/h Cool down to 600°C for 12 hours at a rate of h, then cool in air.
  • High temperature diffusion annealing of electroslag ingots install the furnace at a temperature below 550°C for 4 hours, then heat up to 950°C at a rate of 10°C/h, then heat up to 1100°C at a rate of 15°C/h, hold for 12 hours, and then at 20°C/h The temperature was raised to 1190°C for 48 hours at a rate of h, and then cooled to 850°C for 24 hours at a rate of 15°C/h, and then air-cooled.
  • Electrode forging The heating temperature before forging of the electroslag ingot with a diameter of 1100mm is 1150°C, and the heating time before forging is 10h.
  • the free forging adopts a 3500 ton fast forging machine to draw the length in one direction.
  • the unilateral reduction of each pass is controlled to 25mm, and the final forging temperature is 900°C.
  • the consumable electrode with a diameter of 820mm is finally prepared by forging, turning, and flat head. .
  • Self-consumed remelting 1050mm is selected for the crystallizer, the melting is controlled by the melting rate, and the steady-state melting rate is controlled at 6.0kg/min; the helium cooling is started after the 1500kg smelting is started; after the remaining 2500kg, the current is reduced to adjust the melting rate to 5.0kg/min ; After the remaining 800kg, the heat sealing is started, and the heat sealing is controlled by the current. After the consumable remelting is completed, it is cooled in vacuum for 3 hours, and then the void is transferred to the annealing furnace for stress relief annealing within 2 hours to prevent the ingot from bursting after demoulding.
  • the annealing furnace should be preheated to 450°C for 8 hours to achieve uniform temperature, and then heated at a rate of 10°C/h to 850°C for 24 hours, and then cooled at a rate of 15°C/h to 600°C for 12 hours, and then air-cooled.
  • Test results 706 alloy 1050mm consumable ingots trial-produced by the triple smelting process, weighing 15.8 tons, and no hot cracking; the composition test on the head and tail of the steel ingot, the test results show that there is no obvious burning of Al and Ti elements at the head and tail.
  • the Al element is 0.16% in the head and 0.12% in the tail, and the Ti element is 1.65% in the head and 1.50% in the tail.
  • After the secondary consumable ingot with a diameter of 1050mm is homogenized at high temperature and diffused and annealed, it is polished and forged to prepare forged bars. The bars were inspected by non-destructive flaw detection, and abnormal signals were found at the electroslag remelting joints, and an obvious black spot defect was found at the joints after anatomy.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Abstract

一种高铌高温合金大尺寸铸锭的冶炼工艺及高铌高温合金大尺寸铸锭，该冶炼工艺包括：真空感应熔炼，制得多支成分相同的真空感应锭，进而制得相同数量的电渣电极，进行交换电渣重熔，再利用所得电渣锭制得自耗电极，然后以该自耗电极为起始原料，进行多次真空自耗重熔。采用该工艺能够实现锭重15吨以上、直径800mm以上的高铌高温合金大尺寸铸锭的制备，最大限度地抑制黑斑和白斑冶金缺陷形成，降低元素偏析程度，有效预防钢锭炸裂。

Description

一种高铌高温合金大尺寸铸锭的冶炼工艺及高铌高温合金大尺寸铸锭 技术领域
本发明涉及高铌高温合金大尺寸铸锭技术领域，更具体地说，它涉及一种高铌高温合金大尺寸铸锭的冶炼工艺及采用该冶炼工艺制得的高铌高温合金大尺寸铸锭。
背景技术
随着工燃气轮机热效率和功率的提升，200MW级以上的先进重型燃机的透平轮盘材料逐渐由合金钢升级为高温合金。与合金钢相比，高温合金500℃的屈服强度提升40％以上，550℃的100000h持久强度提升300％以上，可以显著提升重型燃机轮盘的高温强度和长时持久性能，有利于简化结构设计，提高可靠性和燃机热效率。
重型燃气轮机透平轮盘的尺寸普遍超过2000mm，所需锻件重量超过10吨，所需铸锭的重量则超过15吨。所制备的透平轮盘要在服役环境下长时可靠服役10万小时以上，对铸锭的冶金质量提出了很高的要求。
对于Nb含量超过3％的706和718合金，欧美生产10吨以上的高温大锭型普遍采用“真空感应熔炼+电渣重熔+真空自耗重熔”的三联冶炼工艺。例如，专利US20020170386A1给出了一种718及其它合金直径762mm以上大锭型的三联冶炼工艺。三联冶炼设备使用过程中，锭型和电极的直径需要进行匹配，专利中给出了几种锭型和电极的匹配例子。
对于重量超过15吨的高温合金自耗锭，考虑到三联冶炼环节间的损耗(电极车光和平头尾)，真空感应锭的重量超过20吨，对真空感应炉和电渣重熔炉的设备能力要求更高。目前，国内生产15吨以上高温合金大锭型的主要技术瓶颈在于，没有公称容量大于20吨级的真空感应熔炼装备，无法制备20吨级以上的单支真空感应电极锭坯。为了解决此问题，适应国内设备情况，只能采用真空感应炉浇注2支10吨级的感应锭，再利用双支臂交换电极重熔，用两个小吨位的短电极制备大吨位的高温合金电渣锭，再通过锻制电极用于后续的真空自耗重熔。
由于706和718等合金的合金化程度高，对自耗重熔冶炼工艺参数十分敏感，参数波动极易产生黑斑、白斑等冶炼缺陷，因而对自耗重熔过程冶炼工艺参数的稳定性要求。然而，采用双支臂交换电极重熔的方法制备大尺寸电渣锭，在电极交换过程中容易形成接注、流钢、成分波动和夹杂等一系列的质量缺陷。即使通过后续的高温扩散退火和电极锻制也无法完全 消除上述质量缺陷。在随后的真空自耗重熔过程中，当熔炼至电极接头处时，上述质量缺陷会造成自耗重熔工艺冶炼参数出现波动，进而影响自耗锭的冶金质量。
发明内容
针对现有技术存在的不足，本发明的第一个目的在于提供一种高铌高温合金大尺寸铸锭的冶炼工艺，其能够有效解决高铌高温合金大尺寸铸锭的直径或重量扩大后因偏析加剧形成黑斑和白斑冶金缺陷问题，因热应力大造成的钢锭炸裂问题，以及因电渣重熔设备电极臂吨位限制造成的钢锭重量无法增大的问题，进而能够实现锭重15吨以上、直径800mm以上的高铌高温合金大尺寸铸锭的制备，最大限度地抑制黑斑和白斑冶金缺陷形成，降低元素偏析程度，有效预防钢锭炸裂。
本发明的第二个目的在于提供一种采用上述冶炼工艺制得的高铌高温合金大尺寸铸锭，所得铸锭重量至少可达15吨，未出现热裂，且无黑斑、白斑等冶金缺陷，Al、Ti元素无明显烧损，采用该铸锭所锻造的棒材，经无损探伤检验，发现电渣重熔接头处无异常信号。
为实现上述目的，本发明提供了如下技术方案：一种高铌高温合金大尺寸铸锭的冶炼工艺，其包括以下步骤：
真空感应熔炼：采用纯金属原材料和/或返回料为原料，进行真空感应熔炼，浇注多支成分相同的真空感应锭；
交换电渣重熔：利用所制成的真空感应锭制得相同数量的电渣电极；采用所有制得的电渣电极，氩气保护状态下进行交换电渣重熔，交换电渣重熔结束后，冷却，脱模，制得电渣锭：进行多次真空自耗重熔：对脱模的电渣锭进行一次退火、二次退火、锻造拔长至预定尺寸，制得一次自耗电极，其中二次退火温度高于一次退火温度；然后以所述一次自耗电极为起始原料，进行至少两次真空自耗重熔，每次真空自耗重熔所得自耗重熔锭用于制成下一次真空自耗重熔待用的自耗电极，且每次真空自耗重熔所得自耗重熔锭的直径依次增大，直至末次真空自耗重熔过程中熔速波动不超过稳态熔速的±10％，最后利用末次真空自耗重熔所得末次自耗重熔锭，制备目标直径的铸锭。
本发明的上述技术方案中，为了克服真空感应熔炼装备容量不足的问题，采用常规吨位(如12吨)的真空感应炉制备多支成分相同的感应锭(这样也降低了对单支感应锭重量的要求)，从而制备多支电渣电极，然后采用电极交换重熔，制备大吨位的电渣锭，然后进行多次真空自耗重熔，其中，通过一次真空自耗重熔，可改善电极交换接头处的冶金质量，再通过二次或更多次真空自耗重熔，可彻底解决冶金质量问题，从而制备处高质量的、无冶金缺陷的至少达15吨级的高温合金大尺寸自耗锭。考虑到损耗，多支真空感应锭的重量之 和应是铸锭目标重量的125％～160％。
在优选的实施方案中，真空感应熔炼步骤中，原料中Nb含量为2.8～5.5wt.％，Al含量为0.2～1.0wt.％、Ti含量为0.5～2.0wt.％。。
在优选的实施方案中，真空感应熔炼步骤中，原料熔化温度为1400～1550℃，熔清后，在电磁搅拌作用下精炼15～120min，精炼温度为1350～1550℃；然后冷却1～10小时后，脱模，得真空感应锭；重复多次该真空感应熔炼过程，得多支成分相同的真空感应锭。
事实上，当真空感应锭直径超过800mm，单支重量超过10吨时，对于高铌的高温合金大尺寸感应锭在浇铸完成后的凝固过程中会产生很大的热应力，尤其是含Al、Ti的时效析出型合金，在冷却至强化型时效析出温度范围后，会析出强化相造成更大的组织应力，严重时会导致钢锭直接炸裂。但是脱模时间过短，钢锭未完全凝固，过早脱模易开裂。
为此，在优选的实施方案中，制备电渣电极的方式为，对每支真空感应锭直接去应力退火，退火时，预先升温至600～800℃，而后以5～45℃/h的速度升温至800～1000℃并保温4～32h，而后以1～35℃/h的速度冷却至600～800℃保温4～32h；而后空冷然后再车光、平头尾，即得电渣电极。通常，所得电渣电极的直径应与对应真空自耗重熔步骤所用真空自耗电弧炉的配套结晶器的直径相适配，即配套结晶器与电极的直径应保持一个合适比例，即充填比，约为0.8～0.9。
本申请通过采用上述方案，对真空感应锭直接去应力退火，优点很多，第一，能够及时避免钢锭脱模后因空冷使温度落入时效析出区间形成过大的组织应力；第二，能够以合理的升温速度提升钢锭温度，针对高温合金热导率低的问题，避免钢锭内外产生较大的热应力；第三，在800～1000℃保温一定时间可使钢锭温度充分均匀，释放凝固内应力；第四，通过1～35℃/h的缓冷和600～800℃一定时间保温能够有效避免钢锭再次形成较大的热应力和组织应力。
在优选的实施方案中，进行交换电渣重熔时，所采用的渣系为(CaF 2-CaO-Al 2O 3-TiO 2)四元渣，(CaF 2-CaO-Al 2O 3-TiO 2)四元渣中CaF 2占60～75wt.％，CaO占10～25wt.％，Al 2O 3占10～25wt.％，TiO 2占1～10wt.％；电渣重熔的稳态熔速控制为5～15kg/min，并且，每次电极交换前，当前一支电极剩余重量500kg～1000kg时，在稳态熔速基础上以0.5～2kg/min的斜率提高熔速至12～25kg/min时，保持稳定至开始交换电渣电极，且交换电极过程保持交换前的冶炼参数，交换时间不超过2min；每次电极交换完成后，当后一支电极熔化100kg～500kg后，以0.5～2kg/min的斜率降低熔速至稳态熔速5～15kg/min，继续重熔，至最后一支电极剩余200～600kg后开始热封顶；交换电渣重熔结束后，冷却2～10h，脱模， 得电渣锭。
通过采用上述技术方案，电渣中TiO 2的含量控制为1～10wt.％，可解决电渣锭头尾Ti元素的烧损问题。针对直径大于1000mm锭型，电渣重熔的稳态熔速控制为5～15kg/min，后续通过调整交换电极前后的熔速，能够合理增大交换电极时的熔池深度，可以解决交换电极过程时熔炼暂停引起的熔池流动性降低，降低电极瞬间埋入渣池对熔池的扰动，减少夹杂、接注等冶金质量问题。
在优选的实施方案中，进行多次真空自耗重熔步骤中，对脱模的电渣锭进行一次退火、二次退火、锻造拔长至预定尺寸以制得自耗电极的具体实现方式如下，
对电渣锭，在脱模后0.5～2h内启动一次退火，具体为，预先加热至300～550℃，保温12～32h实现均温，然后以1～25℃/h的速度升温至600～750℃保温4～32h，而后以5～35℃/h的速度升温至800～1000℃保温4～32h，而后以1～35℃/h的速度冷却至550～750℃保温4～32h，而后空冷；
对一次退火完成后的电渣锭进行二次退火，具体为，在550～750℃以下保温4～24h，而后以5～35℃/h的速度升温至800～1000℃，而后以1～25℃/h的速度升温至1050～1150℃保温4～32h，而后以1～25℃/h的速度升温至1150～1250℃保温24～72h，而后以1～35℃/h的速度冷却至800～950℃保温4～32h，而后空冷；
对二次退火后电渣锭，在锻前加热至1100～1180℃，锻前加热时间为4～12h，自由锻采用3000吨以上的快锻机单向拔长，每道次单边压下量控制为5～30mm，终锻温度为850～1000℃；
对自由锻拔长之后的钢锭，车光、平头尾，得到一次自耗电极。通常，一次自耗电极的直径应与一次真空自耗重熔所用真空自耗电弧炉的配套结晶器的直径相适配。
采用上述技术方案的原因在于，对获得的高铌高温合金直径为1000mm以上的电渣锭，凝固过程的热应力极大，十分容易炸裂；由于自耗电极和对应的结晶器要求有合理的充填比，该大尺寸的电渣锭无法直接用于一次自耗重熔，需要利用自由锻拔长以减小直径，例如可以是800～900mm；但是由于电渣锭的直径过大，凝固偏析十分严重，存在严重的枝晶元素偏析和枝晶间低熔点相，热塑性极差。
为了解决直径1000mm以上的高铌高温合金电渣锭的热应力问题，于是，本申请在电渣重熔结束后，在所采用的电渣重熔炉内水冷结晶器中通水冷却2～10h，以保证钢锭充分凝固且冷却至时效析出温度以下，脱模后0.5～2h内启动一次退火。一次退火时，预先加热至300～550℃，避免温度过高产生过大的热应力，而后在300～550℃保温12～32h实现均温， 然后以1～25℃/h的速度升温至600～750℃保温4～32h，而后以5～35℃/h的速度升温至800～1000℃保温4～32h，而后以1～35℃/h的速度冷却至550～750℃保温4～32h，而后空冷。通过一次退火，可释放电渣锭凝固过程中由于温度梯度形成的热应力，同时利用过时效处理使强化相粗化避免形成组织应力，进而抑制大尺寸高温合金电渣锭脱模后直接炸裂。
为了提高直径800mm以上的高铌高温合金电渣锭的热塑性，电渣锭应在退火完成后进行二次退火，即高温扩散退火。为了避免热应力过大，升温速度要严格控制，因此，在550～750℃以下温度将电渣锭装炉保温4～24h，而后以5～35℃/h的速度升温至800～1000℃，而后以1～25℃/h的速度升温至1050～1150℃保温4～32h，而后以1～25℃/h的速度升温至1150～1250℃保温24～72h，而后以1～35℃/h的速度冷却至800～950℃保温4～32h，而后空冷。通过多阶段的缓慢升温，可避免钢锭中形成过大的热应力造成炸裂，另外通过高温长时扩散退火，可使合金中的低熔点相回溶、减弱枝晶元素偏析，进而提高钢锭的热塑性，为后续锻造制备自耗电极提供高塑性的钢锭。
在优选的实施方案中，进行多次真空自耗重熔步骤中，其中的一次真空自耗重熔和二次真空自耗重熔按如下方式进行：
一次真空自耗重熔时，稳态熔速控制为3.5～7.5kg/min；开始熔炼800～2000kg后启动氦气冷却；剩余1500～5000kg后降低电流调整熔速至3.0～7.0kg/min；剩余200～1000kg后启动热封顶，制得一次自耗重熔锭；
二次真空自耗重熔时，首先对一次自耗重熔锭车光、平头尾，得到直径直径与二次真空自耗重熔所用结晶器直径相适配的二次自耗电极；
进行二次真空自耗重熔时，稳态熔速控制为4.0～8.5kg/min；开始熔炼1000～3000kg后通入氦气冷却；剩余2000～5500kg后降低电流调整熔速至3.0～7.5kg/min；剩余250～1500kg后启动热封顶；
二次自耗重熔完成后，真空冷却1～8h，而后在2h内启动去应力退火；退火时，预先加热至300～750℃，保温4～32h实现均温，然后以5～50℃/h的速度升温至800～1000℃，保温4～32h，而后以1～35℃/h的速度冷却至550～750℃保温4～32h，而后空冷。
在上述一次真空自耗重熔过程中，由于锭子凝固过程中体积会出现缩小，与结晶器壁出现缝隙，在真空条件下钢锭与结晶器外壁的冷却水无法直接接触实现散热，为此通入氦气导热；熔炼早期钢锭可通过底部与结晶器散热，当熔炼至一定阶段后底部散热受限，为此需要在熔炼一定阶段后通入适量氦气，氦气过多会冲破熔池不利于熔炼稳定性，氦气过少则起不到冷却效果；由于钢锭过大，钢锭凝固越多则热容量越大，传热越困难，为此在熔炼末 期需要适当降低熔速，稳定熔池深度，进而降低冶金缺陷的形成几率；根据一次自耗电极剩余重量判断热封顶的时机，能够节省钢锭切除量，提高成材率。
在一次真空自耗重熔过程中，由于一次自耗电极是利用多支真空感应锭交换电渣重熔制备的电渣锭锻制而成的，电极交换接头处存在着冶金质量的波动，即使通过高温扩散和锻造也无法完全消除。由于自耗重熔过程对电极质量十分敏感，在重熔至电极交换接头处时易出现熔速波动、电极掉块等异常问题，易形成黑斑和白斑等冶金缺陷，且无法通过后续的高温扩散退火、锻造或热处理工序消除，严重时会直接造成所制备的棒材或锻件报废。为此，本申请将一次自耗重熔锭车光、平头尾以制备二次自耗电极，再进行二次自耗重熔。由于二次自耗重熔后的钢锭直径超过800mm，会存在很大的热应力，故在二次自耗重熔完成后，要真空冷却，而后破空在2h内启动去应力退火，避免钢锭脱模后炸裂，退火时应预先加热至300～750℃保温4～32h实现均温，然后以5～50℃/h的速度升温至800～1000℃保温4～32h，而后以1～35℃/h的速度冷却至550～750℃保温4～32h，而后空冷，后续采用这种方式，可释放一次自耗重熔锭凝固过程中由于温度梯度形成的热应力，同时利用过时效处理，使强化相粗化，避免形成组织应力，进而抑制大尺寸高温合金电渣锭脱模后直接炸裂。
在优选的实施方案中，若二次自耗重熔过程中熔速波动超过稳态熔速的±10％，则利用所得二次自耗重熔锭，采用制备一次自耗电极的方式，进行同样的一次退火、二次退火、锻造拔长，制得下一次真空自耗重熔待用的自耗电极，然后，再次重复二次自耗重熔过程。通常，所述下一次真空自耗重熔待用的自耗电极的直径应与下一次真空自耗重熔所用真空自耗电弧炉的配套结晶器的直径相适配。
本发明提供的采用上述冶炼工艺所制备的高铌高温合金大尺寸铸锭，具体为直径为在800mm以上的706合金，按质量百分比，该706合金的化学成分为：
C≤0.02％，Cr 15.5～16.5％，Ni 40.0～43.0％，Nb 2.8～3.2％，Ti 1.5～1.8％，Al 0.1～0.3％，Si≤0.10％，Mn≤0.20％，P≤0.015％，S≤0.0013％，Co≤0.30％，Mo≤0.20％，B≤0.006％，Cu≤0.30％，Ca≤0.005％，N≤0.006％，O≤0.005％，Fe余量。
本发明提供的采用上述冶炼工艺所制备的高铌高温合金大尺寸铸锭，具体为直径在800mm以上的718合金，按质量百分比，该718合金的化学成分为：
C 0.005～0.04％，Cr 17.0～19.0％，Ni 52.0～55.0％，Nb 4.9～5.5％，Ti 0.75～1.15％，Al 0.35～0.65％，Si≤0.10％，Mn≤0.15％，P≤0.008％，S≤0.002％，Co≤0.50％，Mo 2.8～3.3％，B≤0.006％，Cu≤0.10％，Ca≤0.005％，N≤0.01％，O≤0.003％，Fe余量。
本发明具有以下优点：
1、能够突破感应炉和气氛保护电渣炉的吨位限制，采用常规吨位(如12吨)真空感应炉制备多支电极，再利用电渣炉交换电极将多支感应锭熔炼为1支电渣锭，再用于制造至少15吨级的真空自耗锭；
2、能够利用电极支臂吨位受限制的电渣炉，采用交换电渣重熔的方法制备20吨级的高温合金电渣锭；
3、通过交换电渣重熔制备的电渣锭经高温扩散退火获得一定热塑性，再利用自由锻造开坯拔长制备合适直径的自耗电极，可以显著改善一次自耗重熔过程的熔炼稳定性；
4、采用一次自耗重熔钢锭制备的二次自耗电极用于二次自耗重熔，必要时，进一步进行多次自耗重熔，能够有效解决交换电渣重熔过程中电渣锭交换电极接头处的夹杂等冶金缺陷问题，以制备直径800mm以上、锭重超过15吨的无冶金缺陷的高铌高温合金自耗锭。
具体实施方式
以下结合实施例对本发明作进一步详细说明。
实施例1：
本实施例用于说明制备706合金(直径1050mm自耗锭)的方法。
目标706合金成分(按质量百分比)：
C 0.018％，Cr 15.8％，Ni 41.5％，Nb3.01％，Ti1.72％，Al 0.25％，Si0.02％，Mn0.01％，P0.006％，S0.0006％，Co0.02％，Mo0.01％，B0.004％，Cu0.02％，Ca0.004％，N0.005％，O0.002％，Fe余量。
具体制备方法如下：
真空感应熔炼：根据设计的合金成分要求，按单位重量的合金所需元素称取50％返回料，剩余采用全新金属原材料。采用12吨真空感应炉，熔化温度上限为1550℃，熔清后检测钢液成分，通过补加新金属，控制钢液中Nb含量约3.02wt.％，Ti含量约1.80wt.％，Al含量约0.30wt.％，根据补加金属料的数量，采用电磁搅拌下精炼15-30min，精炼温度为1350℃，出钢温度为1400℃。浇钢完成后，炉冷4小时后脱模，制得1支直径820mm的12吨真空电极锭，然后直接进行退火处理。退火炉预先加热至600℃，而后以5℃/h的速度升温至800℃保温24h，而后以1℃/h的速度冷却至600℃保温10h，而后空冷。
将退火后的真空感应锭车/磨光、平头尾，用于制备电渣电极。
电渣重熔：结晶器选用直径1100mm，渣系选用(CaF 2-CaO-Al 2O 3-TiO 2)四元渣，具体组成为：CaF 260％，CaO10％，Al 2O 325％，TiO 210％。稳态熔速为15kg/min，熔炼过程中通入0.2bar压力的Ar气保护，避免熔炼过程中钢液与空气中的氧气和氮气接触。电极交换 前，在剩余重量800kg时，调整输入功率和电压提高熔速，在稳态熔速基础上以1.05kg/min的斜率提高熔速，至25kg/min时保持稳定至开始交换电渣电极。交换电极过程保持交换前的冶炼参数，交换时间不能超过2min。交换电极完成后，第二支电极熔化100kg后，通过调整输入功率和电压提高熔速，以0.50kg/min的斜率降低至10kg/min，至第二支电极剩余200kg后开始热封顶。
电渣重熔结束后，在炉内水冷结晶器中通水冷却4h，脱模后0.5h内转移至退火炉内去应力退火。退火炉应预先加热至300℃，在300℃保温12h，然后以5℃/h的速度升温至600℃保温4h，而后以10℃/h的速度升温至800℃保温5h，而后以5℃/h的速度冷却至600℃保温12h，而后空冷。
电渣锭高温扩散退火：在550℃以下温度装炉保温4h，而后以10℃/h的速度升温至800℃，而后以5℃/h的速度升温至1050℃保温4h，而后以5℃/h的速度升温至1150℃保温24h，而后以5℃/h的速度冷却至800℃保温32h，而后空冷。
电极锻制：直径1100mm电渣锭的锻前加热温度选用1100℃，锻前加热时间为4h。自由锻采用3500吨快锻机单向拔长，每道次单边压下量控制为25mm，终锻温度为850℃，最终经锻制、车光、平头尾制备为直径820mm一次自耗电极，用于一次真空自耗重熔。
一次真空自耗重熔：结晶器选用直径920mm，自耗重熔通过熔速进行控制，稳态熔速控制为3.5kg/min；开始熔炼800kg后启动氦气冷却；剩余1500kg后降低电流调整熔速至3.0kg/min；剩余200kg后启动热封顶，热封顶通过电流控制。将一次自耗重熔锭车光、平头尾加工至直径900mm，用于二次真空自耗重熔。
二次真空自耗重熔：结晶器选用1050mm，熔通过熔速进行控制，稳态熔速控制为4.0kg/min；开始熔炼1000kg后启动氦气冷却；剩余2000kg后降低电流调整熔速至3.0kg/min；剩余250kg后启动热封顶，热封顶通过电流控制。二次真空自耗重熔完成后，真空冷却3h，而后破空在2h内转移至退火炉内去应力退火，避免钢锭脱模后炸裂。退火炉应预先加热至300℃保温4h实现均温，然后以5℃/h的速度升温至800℃保温5h，而后以5℃/h的速度冷却至550℃保温5h，而后空冷。
试验结果：试制的706合金1050mm自耗锭，重量为15.5吨，未出现热裂，且无黑斑、白斑等冶金缺陷。对钢锭的头尾进行成分测试，测试结果表明，头尾Al、Ti元素无明显烧损，Al元素为头部0.27％、尾部0.24％，Ti元素为头部1.68％、尾部1.78％。将直径1050mm的二次自耗重熔锭高温均匀化扩散退火处理后，车光后安排锻造，制备锻造棒材。棒材经无损探伤检验，发现电渣重熔接头处无异常信号，表明通过二次真空自耗重熔可以有 效解决706合金电渣接头处的冶金质量问题。
实施例2
本实施例用于说明制备706合金(直径1050mm自耗锭)的方法。
目标706合金成分(按质量百分比)：
C 0.011％，Cr 16.2％，Ni 42.5％，Nb2.80％，Ti1.57％，Al 0.15％，Si0.02％，Mn0.02％，P0.008％，S0.0004％，Co0.01％，Mo0.02％，B0.003％，Cu0.05％，Ca0.001％，N0.0045％，O0.0025％，Fe余量。
具体制备方法如下：
真空感应熔炼：根据设计的合金成分要求，按单位重量的合金所需元素称取50％返回料，剩余采用全新金属原材料。采用12吨真空感应炉，熔化温度上限为1550℃，熔清后检测钢液成分，通过补加新金属，控制钢液中Nb含量约2.90wt.％，Ti含量约1.62wt.％，Al含量约0.20wt.％，采用电磁搅拌下精炼40min，精炼温度为1480℃，出钢温度为1500℃。分两次浇钢，完成后，炉冷4小时后脱模，制得2支直径820mm的12吨自耗锭，然后直接进行退火处理。退火炉预先加热至650℃，而后以25℃/h的速度升温至900℃保温24h，而后以15℃/h的速度冷却至700℃保温10h，而后空冷。
将退火后的真空感应锭车光、平头尾，用于制备电渣电极。
电渣重熔：结晶器选用直径1100mm，渣系选用(CaF 2-CaO-Al 2O 3-TiO 2)四元渣，具体组成为：CaF 264％，CaO 15％，Al 2O 315％，TiO 2 6％。稳态熔速为10kg/min，熔炼过程中通入0.2bar压力的Ar气保护，避免熔炼过程中钢液与空气中的氧气和氮气接触。电极交换前，在剩余重量500kg时，调整输入功率和电压提高熔速，在稳态熔速基础上以0.55kg/min的斜率提高熔速，至15kg/min时保持稳定至开始交换电渣电极。交换电极过程保持交换前的冶炼参数，交换时间不能超过2min。交换电极完成后，第二支电极熔化200kg后，通过调整输入功率和电压提高熔速，以0.75kg/min的斜率降低至10kg/min，至第二支电极剩余500kg后开始热封顶。
电渣重熔结束后，在炉内水冷结晶器中通水冷却4h，脱模后0.5h内转移至退火炉内去应力退火。退火炉应预先加热至450℃，在450℃保温24h，然后以15℃/h的速度升温至650℃保温4h，而后以25℃/h的速度升温至950℃保温12h，而后以15℃/h的速度冷却至600℃保温12h，而后空冷。
电渣锭高温扩散退火：在550℃以下温度装炉保温4h，而后以10℃/h的速度升温至950℃，而后以15℃/h的速度升温至1100℃保温12h，而后以20℃/h的速度升温至1190℃保 温48h，而后以15℃/h的速度冷却至850℃保温24h，而后空冷。
电极锻制：直径1100mm电渣锭的锻前加热温度选用1150℃，锻前加热时间为10h。自由锻采用3500吨快锻机单向拔长，每道次单边压下量控制为25mm，终锻温度为900℃，最终经锻制、车光、平头尾制备为直径820mm一次自耗电极，用于一次真空自耗重熔。
一次真空自耗重熔：结晶器选用直径920mm，自耗重熔通过熔速进行控制，稳态熔速控制为5.5kg/min；开始熔炼1000kg后启动氦气冷却；剩余2000kg后降低电流调整熔速至4.0kg/min；剩余500kg后启动热封顶，热封顶通过电流控制。将一次自耗重熔锭车光、平头尾加工至直径900mm，用于二次真空自耗重熔。
二次真空自耗重熔：结晶器选用1050mm，熔通过熔速进行控制，稳态熔速控制为6.5kg/min；开始熔炼1500kg后启动氦气冷却；剩余2500kg后降低电流调整熔速至6.0kg/min；剩余800kg后启动热封顶，热封顶通过电流控制。二次真空自耗重熔完成后，真空冷却3h，而后破空在2h内转移至退火炉内去应力退火，避免钢锭脱模后炸裂。退火炉应预先加热至450℃保温8h实现均温，然后以10℃/h的速度升温至850℃保温24h，而后以15℃/h的速度冷却至600℃保温12h，而后空冷。
二次真空自耗重熔过程中熔炼至电极接头处时，出现了以下关键熔炼参数的波动：电流波动超过±1000A，电压波动超过±2V，熔速波动超过±0.6kg/min。这表明熔炼过程二次自耗重熔过程仍不稳定，电渣交换重熔阶段接头处的冶金缺陷遗留至了二次自耗重熔锭中，为此需要进行第三次自耗重熔。
二次真空自耗锭高温扩散退火：将二次自耗锭在550℃以下温度装炉保温4h，而后以10℃/h的速度升温至950℃，而后以15℃/h的速度升温至1100℃保温12h，而后以20℃/h的速度升温至1190℃保温48h，而后以15℃/h的速度冷却至850℃保温24h，而后空冷。
电极锻制：直径1050mm自耗锭的锻前加热温度选用1150℃，锻前加热时间为10h。自由锻采用3500吨快锻机单向拔长，每道次单边压下量控制为25mm，终锻温度为900℃，最终经锻制、车光、平头尾制备为直径900mm三次自耗电极，用于三次真空自耗重熔。
三次真空自耗重熔：结晶器选用1050mm，熔通过熔速进行控制，稳态熔速控制为6.5kg/min；开始熔炼1500kg后启动氦气冷却；剩余2500kg后降低电流调整熔速至6.0kg/min；剩余800kg后启动热封顶，热封顶通过电流控制。二次真空自耗重熔完成后，真空冷却3h，而后破空在2h内转移至退火炉内去应力退火，避免钢锭脱模后炸裂。退火炉应预先加热至450℃保温8h实现均温，然后以10℃/h的速度升温至850℃保温24h，而后以15℃/h的速度冷却至600℃保温12h，而后空冷。
试验结果：试制的706合金1050mm自耗锭，重量为16.2吨，未出现热裂，且无黑斑、白斑等冶金缺陷。对钢锭的头尾进行成分测试，测试结果表明，头尾Al、Ti元素无明显烧损，Al元素为头部为0.17％、尾部为0.12％，Ti元素为头部为1.65％、尾部为1.47。将直径1050mm的三次自耗重熔锭高温均匀化扩散退火处理后，车光后安排锻造，制备锻造棒材。棒材经无损探伤检验，发现电渣重熔接头处无异常信号，表明通过三次真空自耗重熔可以有效解决706合金电渣接头处的冶金质量问题。
实施例3
本实施例用于说明制备718合金(直径1050mm自耗锭)的方法。
目标718合金成分为(按质量百分比)：
C 0.015％，Cr 18.5％，Ni 53.5％，Nb5.05％，Ti0.92％，Al 0.55％，Si0.04％，Mn0.05％，P0.006％，S0.0008％，Co0.02％，Mo 2.95％，B0.004％，Cu0.05％，Ca0.001％，N0.0048％，O0.0024％，Fe余量。
具体制备方法如下：
真空感应熔炼：根据设计的合金成分要求，按单位重量的合金所需元素称取40％返回料，剩余采用全新金属原材料。采用12吨真空感应炉，熔化温度上限为1550℃，熔清后检测钢液成分，通过补加新金属，控制钢液中Nb含量约5.08wt.％，Ti含量约0.97wt.％，Al含量约0.60wt.％，采用电磁搅拌下精炼40min，精炼温度为1480℃，出钢温度为1500℃。分两次浇钢，完成后，炉冷6小时后脱模，制得2支直径820mm的12吨自耗锭，然后直接进行退火处理。退火炉预先加热至800℃，而后以45℃/h的速度升温至1000℃保温32h，而后以35℃/h的速度冷却至780℃保温32h，而后空冷。
将退火后的真空感应锭车光、平头尾，用于制备电渣电极。
电渣重熔：结晶器选用直径1100mm，渣系选用(CaF 2-CaO-Al 2O 3-TiO 2)四元渣，具体组成为：CaF 275％，CaO25％，Al 2O 310％，TiO 21％。稳态熔速为5kg/min，熔炼过程中通入0.2bar压力的Ar气保护，避免熔炼过程中钢液与空气中的氧气和氮气接触。电极交换前，在剩余重量1000kg时，调整输入功率和电压提高熔速，在稳态熔速基础上以2kg/min的斜率提高熔速至12kg/min时保持稳定至开始交换电渣电极。交换电极过程保持交换前的冶炼参数，交换时间不能超过2min。交换电极完成后，第二支电极熔化500kg后，通过调整输入功率和电压提高熔速，以2kg/min的斜率降低至15kg/min，至第二支电极剩余600kg后开始热封顶。
电渣重熔结束后应在炉内水冷结晶器中通水冷却4h，脱模后1h内转移至退火炉内去 应力退火。退火炉应预先加热至550℃，在550℃保温32h，然后以25℃/h的速度升温至750℃保温4h，而后以30℃/h的速度升温至1000℃保温32h，而后以35℃/h的速度冷却至750℃保温32h，而后空冷。
电渣锭高温扩散退火：在550℃以下温度装炉保温4h，而后以5℃/h的速度升温至1000℃，而后以25℃/h的速度升温至1150℃保温32h，而后以25℃/h的速度升温至1250℃保温72h，而后以35℃/h的速度冷却至950℃保温32h，而后空冷。
电极锻制：直径1100mm电渣锭的锻前加热温度选用1150℃，锻前加热时间为12h。自由锻采用3500吨快锻机单向拔长，每道次单边压下量控制为25mm，终锻温度为1000℃，最终经锻制、车光、平头尾制备为直径820mm一次自耗电极，用于一次真空自耗重熔。
一次真空自耗重熔：结晶器选用直径920mm，自耗重熔通过熔速进行控制，稳态熔速控制为7.5kg/min；开始熔炼2000kg后启动氦气冷却；剩余1000kg后降低电流调整熔速至7.0kg/min；剩余1000kg后启动热封顶，热封顶通过电流控制。将一次自耗重熔锭车光、平头尾加工至直径900mm，用于二次真空自耗重熔。
二次真空自耗重熔：结晶器选用1050mm，熔通过熔速进行控制，稳态熔速控制为8.5kg/min；开始熔炼3000kg后启动氦气冷却；剩余5500kg后降低电流调整熔速至7.5kg/min；剩余1500kg后启动热封顶，热封顶通过电流控制。二次真空自耗重熔完成后，真空冷却3h，而后破空在2h内转移至退火炉内去应力退火，避免钢锭脱模后炸裂。退火炉应预先加热至750℃保温32h实现均温，然后以50℃/h的速度升温至1000℃保温32h，而后以35℃/h的速度冷却至750℃保温32h，而后空冷。
试验结果：试制的718合金1050mm自耗锭，重量为15吨，未出现热裂，且无黑斑、白斑等冶金缺陷。对钢锭的头尾进行成分测试，测试结果表明，头尾Al、Ti元素无明显烧损，Al元素为头部0.60％、尾部0.48％，Ti元素为头部0.87％、尾部0.98％。将直径1050mm的二次自耗重熔锭高温均匀化扩散退火处理后，车光后安排锻造，制备锻造棒材。棒材经无损探伤检验，发现电渣重熔接头处无异常信号，表明通过二次真空自耗重熔可以有效解决718合金电渣接头处的冶金质量问题。
比较例1
比较例1用于说明采用三联制备工艺制备706合金(直径920mm自耗锭)的制备方法。
目标706合金成分同实施例1的706合金成分(按质量百分比)：
C0.018％，Cr 15.8％，Ni 41.5％，Nb3.01％，Ti 1.72％，Al 0.25％，Si0.02％，Mn0.01％，P0.006％，S0.0006％，Co0.02％，Mo0.01％，B0.004％，Cu0.02％，Ca0.004％，N0.005％， O0.002％，Fe余量。
具体制备方法如下：
真空感应熔炼：根据设计的合金成分要求，按单位重量的合金所需元素称取40％返回料，剩余采用全新金属原材料。采用12吨真空感应炉制备2支直径820mm的12吨自耗锭，熔化温度上限为1550℃，熔清后检测钢液成分，通过补加新金属，控制钢液中Nb含量约3.10wt.％，Ti含量约1.82wt.％，Al含量约0.35wt.％，采用电磁搅拌40min；精炼温度为1480℃，出钢温度为1500℃。浇钢完成后炉冷4小时后脱模，然后直接进行退火处理。退火炉预先加热至650℃，而后以25℃/h的速度升温至900℃保温24h，而后以15℃/h的速度冷却至600℃保温10h，而后空冷。
将退火后的真空感应锭车光、平头尾制备电渣电极。
电渣重熔：结晶器选用直径1100mm，渣系选用(CaF 2-CaO-Al 2O 3-TiO 2)四元渣，具体组成为：CaF 270％，CaO15％，Al 2O 315％，TiO 210％。稳态熔速为10kg/min，熔炼过程中通入0.2bar压力的Ar气保护，避免熔炼过程中钢液与空气中的氧气和氮气接触。电极交换前，在剩余重量600kg时，调整输入功率和电压提高熔速，在稳态熔速基础上以0.55kg/min的斜率提高熔速，至15kg/min时保持稳定至开始交换电渣电极。交换电极过程保持交换前的冶炼参数，交换时间不能超过2min。交换电极完成后，第二支电极熔化200kg后，通过调整输入功率和电压提高熔速，以0.75kg/min的斜率降低至10kg/min，至第二支电极剩余500kg后开始热封顶。
电渣重熔结束后应在炉内水冷结晶器中通水冷却4h，脱模后0.5h内转移至退火炉内去应力退火。退火炉应预先加热至450℃，在450℃保温24h，然后以15℃/h的速度升温至650℃保温4h，而后以25℃/h的速度升温至950℃保温12h，而后以15℃/h的速度冷却至600℃保温12h，而后空冷。
电渣锭高温扩散退火：在550℃以下温度装炉保温4h，而后以10℃/h的速度升温至950℃，而后以15℃/h的速度升温至1100℃保温12h，而后以20℃/h的速度升温至1190℃保温48h，而后以15℃/h的速度冷却至850℃保温24h，而后空冷。
电极锻制：直径1100mm电渣锭的锻前加热温度选用1150℃，锻前加热时间为10h。自由锻采用3500吨快锻机单向拔长，每道次单边压下量控制为25mm，终锻温度为900℃，最终经锻制、车光、平头尾制备为直径820mm自耗电极。
自耗重熔：结晶器选用直径920mm，自耗重熔通过熔速进行控制，稳态熔速控制为5.5kg/min；开始熔炼1000kg后启动氦气冷却；剩余2000kg后降低电流调整熔速至4.0kg/min； 剩余500kg后启动热封顶，热封顶通过电流控制。自耗重熔完成后，真空冷却3h，而后破空在2h内转移至退火炉内去应力退火，避免钢锭脱模后炸裂。退火炉应预先加热至450℃保温8h实现均温，然后以10℃/h的速度升温至850℃保温24h，而后以15℃/h的速度冷却至600℃保温12h，而后空冷。
试验结果：采用三联冶炼工艺试制的706合金920mm自耗锭，重量为15吨，未出现热裂；对钢锭的头尾进行成分测试，测试结果表明，头尾Al、Ti元素烧损明显，Al元素为头部0.29％、尾部0.19％，Ti元素为头部1.62％、尾部1.80％。将直径1050mm的二次自耗锭高温均匀化扩散退火处理后，车光后安排锻造，制备锻造棒材。棒材经无损探伤检验，发现电渣重熔接头处有异常信号，解剖发现接头处存在明显的黑斑缺陷。
比较例2：706合金直径1050mm自耗锭
比较例1用于说明采用三联制备工艺制备706合金(直径1050mm自耗锭)的制备方法。
目标706合金成分同实施例2的706合金成分(按质量百分比)：
C 0.011％，Cr 16.2％，Ni 42.5％，Nb2.80％，Ti1.57％，Al 0.15％，Si0.02％，Mn0.02％，P0.008％，S0.0004％，Co0.01％，Mo0.02％，B0.003％，Cu0.05％，Ca0.001％，N0.0045％，O0.0025％，Fe余量。
具体制备方法如下：
真空感应熔炼：根据设计的合金成分要求，按单位重量的合金所需元素称取50％返回料，剩余采用全新金属原材料。采用12吨真空感应炉制备2支直径820mm的12吨自耗锭，熔化温度上限为1550℃，熔清后测得钢液中Nb含量约3.10wt.％，Ti含量约1.72wt.％，Al含量约0.30wt.％，采用电磁搅拌40min；精炼温度为1480℃，出钢温度为1500℃。浇钢完成后炉冷4小时后脱模，然后直接进行退火处理。退火炉预先加热至650℃，而后以25℃/h的速度升温至900℃保温24h，而后以15℃/h的速度冷却至600℃保温10h，而后空冷。
将退火后的真空感应锭车光、平头尾制备电渣电极。
电渣重熔：结晶器选用直径1100mm，渣系选用(CaF 2-CaO-A l2O3-TiO 2)四元渣，具体组成为：CaF 264％，CaO15％，Al 2O 315％，TiO 26％。稳态熔速为10kg/min，熔炼过程中通入0.2bar压力的Ar气保护，避免熔炼过程中钢液与空气中的氧气和氮气接触。电极交换前，在剩余重量600kg时，调整输入功率和电压提高熔速，在稳态熔速基础上以0.55kg/min的斜率提高熔速，至15kg/min时保持稳定至开始交换电渣电极。交换电极过程保持交换前的冶炼参数，交换时间不能超过2min。交换电极完成后，第二支电极熔化200kg后，通过调整输入功率和电压提高熔速，以0.75kg/min的斜率降低至10kg/min，至第二支电极剩余500kg后开 始热封顶。
电渣重熔结束后应在炉内水冷结晶器中通水冷却4h，脱模后0.5h内转移至退火炉内去应力退火。退火炉应预先加热至450℃，在450℃保温24h，然后以15℃/h的速度升温至650℃保温4h，而后以25℃/h的速度升温至950℃保温12h，而后以15℃/h的速度冷却至600℃保温12h，而后空冷。
电渣锭高温扩散退火：在550℃以下温度装炉保温4h，而后以10℃/h的速度升温至950℃，而后以15℃/h的速度升温至1100℃保温12h，而后以20℃/h的速度升温至1190℃保温48h，而后以15℃/h的速度冷却至850℃保温24h，而后空冷。
电极锻制：直径1100mm电渣锭的锻前加热温度选用1150℃，锻前加热时间为10h。自由锻采用3500吨快锻机单向拔长，每道次单边压下量控制为25mm，终锻温度为900℃，最终经锻制、车光、平头尾制备为直径820mm自耗电极。
自耗重熔：结晶器选用1050mm，熔通过熔速进行控制，稳态熔速控制为6.0kg/min；开始熔炼1500kg后启动氦气冷却；剩余2500kg后降低电流调整熔速至5.0kg/min；剩余800kg后启动热封顶，热封顶通过电流控制。自耗重熔完成后，真空冷却3h，而后破空在2h内转移至退火炉内去应力退火，避免钢锭脱模后炸裂。退火炉应预先加热至450℃保温8h实现均温，然后以10℃/h的速度升温至850℃保温24h，而后以15℃/h的速度冷却至600℃保温12h，而后空冷。
试验结果：采用三联冶炼工艺试制的706合金1050mm自耗锭，重量为15.8吨，未出现热裂；对钢锭的头尾进行成分测试，测试结果表明，头尾Al、Ti元素无明显烧损，Al元素为头部0.16％、尾部0.12％，Ti元素为头部1.65％、尾部1.50％。将直径1050mm的二次自耗锭高温均匀化扩散退火处理后，车光后安排锻造，制备锻造棒材。棒材经无损探伤检验，发现电渣重熔接头处有异常信号，解剖发现接头处存在明显的黑斑缺陷。
本具体实施例仅仅是对本发明的解释，其并不是对本发明的限制，本领域技术人员在阅读完本说明书后可以根据需要对本实施例做出没有创造性贡献的修改，但只要在本发明的权利要求范围内都受到专利法的保护。

Claims (10)

  1. 一种高铌高温合金大尺寸铸锭的冶炼工艺，其特征在于，包括以下步骤：
    真空感应熔炼：采用纯金属原材料和/或返回料为原料，进行真空感应熔炼，浇注多支成分相同的真空感应锭；
    交换电渣重熔：利用所制成的真空感应锭制得相同数量的电渣电极；采用所有制得的电渣电极，氩气保护状态下进行交换电渣重熔，交换电渣重熔结束后，冷却，脱模，制得电渣锭：进行多次真空自耗重熔：对脱模的电渣锭进行一次退火、二次退火、锻造拔长至预定尺寸，制得一次自耗电极，其中二次退火温度高于一次退火温度；然后以所述一次自耗电极为起始原料，进行至少两次真空自耗重熔，每次真空自耗重熔所得自耗重熔锭用于制成下一次真空自耗重熔待用的自耗电极，且每次真空自耗重熔所得自耗重熔锭的直径依次增大，直至末次真空自耗重熔过程中熔速波动不超过稳态熔速的±10％，最后利用末次真空自耗重熔所得末次自耗重熔锭，制备目标直径的铸锭。
  2. 根据权利要求1所述的冶炼工艺，其特征在于，真空感应熔炼步骤中，原料中Nb含量为2.8～5.5wt.％，Al含量为0.2～1.0wt.％、Ti含量为0.5～2.0wt.％。
  3. 根据权利要求1所述的冶炼工艺，其特征在于，真空感应熔炼步骤中，熔化温度为1300～1550℃，原料熔清后，在电磁搅拌作用下精炼15～120min，精炼温度为1350～1550℃；然后冷却1～10小时后，脱模，得真空感应锭；重复多次该真空感应熔炼过程，得多支成分相同的真空感应锭。
  4. 根据权利要求1所述的冶炼工艺，其特征在于，制备电渣电极的方式为，对每支真空感应锭直接去应力退火，退火时，预先升温至600～800℃，而后以5～45℃/h的速度升温至800～1000℃并保温4～32h，而后以1～35℃/h的速度冷却至600～800℃保温4～32h，而后空冷，然后再车光、平头尾，即得电渣电极。
  5. 根据权利要求1所述的冶炼工艺，其特征在于，进行交换电渣重熔时，所采用的渣系为(CaF 2-CaO-Al 2O 3-TiO 2)四元渣，(CaF 2-CaO-Al 2O 3-TiO 2)四元渣中CaF 2占60～75wt.％，CaO占10～25wt.％，Al 2O 3占10～25wt.％，TiO 2占1～10wt.％；
    电渣重熔的稳态熔速控制为5～15kg/min，
    并且，每次电极交换前，当前一支电极剩余重量500kg～1000kg时，在稳态熔速基础上以0.5～2kg/min的斜率提高熔速至12～25kg/min时，保持稳定至开始交换电渣电极，且交换电极过程保持交换前的冶炼参数，交换时间不超过2min；每次电极交换完成后，当后一支电极熔化100kg～500kg后，以0.5～2kg/min的斜率降低熔速至稳态熔速5～15kg/min，继续重熔，至最后一支电极剩余200～600kg后开始热封顶；
    交换电渣重熔结束后，冷却2～10h，脱模，得电渣锭。
  6. 根据权利要求1所述的冶炼工艺，其特征在于，进行多次真空自耗重熔步骤中，对脱模的电渣锭进行一次退火、二次退火、锻造拔长至预定尺寸以制得一次自耗电极的具体实现方式如下，
    对电渣锭，在脱模后0.5～2h内启动一次退火，具体为，预先加热至300～550℃，保温12～32h实现均温，然后以1～25℃/h的速度升温至600～750℃保温4～32h，而后以5～35℃/h的速度升温至800～1000℃保温4～32h，而后以1～35℃/h的速度冷却至550～750℃保温4～32h，而后空冷；
    对一次退火完成后的电渣锭进行二次退火，具体为，以5～35℃/h的速度升温至800～1000℃，而后以1～25℃/h的速度升温至1050～1150℃保温4～32h，而后以1～25℃/h的速度升温至1150～1250℃保温24～72h，而后以1～35℃/h的速度冷却至800～950℃保温4～32h，而后空冷；
    对二次退火后电渣锭，在锻前加热至1100～1180℃，锻前加热时间为4～12h，自由锻采用3000吨以上的快锻机单向拔长，每道次单边压下量控制为5～30mm，终锻温度为850～1000℃；
    对自由锻拔长之后的钢锭，车光、平头尾，得到一次自耗电极。
  7. 根据权利要求1所述的冶炼工艺，其特征在于，进行多次真空自耗重熔步骤中，其中的一次真空自耗重熔和二次真空自耗重熔按如下方式进行：
    一次真空自耗重熔时，稳态熔速控制为3.5～7.5kg/min；开始熔炼800～2000kg后启动氦气冷却；剩余1500～5000kg后降低电流调整熔速至3.0～7.0kg/min；剩余200～1000kg后启动热封顶，制得一次自耗重熔锭；
    二次真空自耗重熔时，首先对一次自耗重熔锭车光、平头尾，得到二次自耗电极；
    进行二次真空自耗重熔时，稳态熔速控制为4.0～8.5kg/min；开始熔炼1000～3000kg后通入氦气冷却；剩余2000～5500kg后降低电流调整熔速至3.0～7.5kg/min；剩余250～1500kg后启动热封顶；
    二次自耗重熔完成后，真空冷却1～8h，而后在2h内启动去应力退火；退火时，预先加热至300～750℃，保温4～32h实现均温，然后以5～50℃/h的速度升温至800～1000℃，保温4～32h，而后以1～35℃/h的速度冷却至550～750℃保温4～32h，而后空冷。
  8. 根据权利要求1-7任一所述的冶炼工艺，其特征在于，若二次自耗重熔过程中熔速波动超过稳态熔速的±10％，则利用所得二次自耗重熔锭，采用制备一次自耗电极的方式，进行同 样的一次退火、二次退火、锻造拔长，制得下一次真空自耗重熔待用的自耗电极，然后，再次重复二次自耗重熔过程。
  9. 采用权利要求1-8任一所述的一种高铌高温合金大尺寸铸锭的冶炼工艺所制备的高铌高温合金大尺寸铸锭，其特征在于，按质量百分比，所述高铌高温合金大尺寸铸锭为直径在800mm以上的706合金，706合金的化学成分为：
    C≤0.02％，Cr 15.5～16.5％，Ni 40.0～43.0％，Nb 2.8～3.2％，Ti 1.5～1.8％，Al 0.1～0.3％，Si≤0.10％，Mn≤0.20％，P≤0.015％，S≤0.0013％，Co≤0.30％，Mo≤0.20％，B≤0.006％，Cu≤0.30％，Ca≤0.005％，N≤0.006％，O≤0.005％，Fe余量。
  10. 采用权利要求1-8任一所述的一种高铌高温合金大尺寸铸锭的冶炼工艺所制备的高铌高温合金大尺寸铸锭，其特征在于，按质量百分比，所述高铌高温合金大尺寸铸锭为直径在80mm以上的718合金，718合金的化学成分为：
    C 0.005～0.04％，Cr 17.0～19.0％，Ni 52.0～55.0％，Nb 4.9～5.5％，Ti 0.75～1.15％，Al 0.35～0.65％，Si≤0.10％，Mn≤0.15％，P≤0.008％，S≤0.002％，Co≤0.50％，Mo 2.8～3.3％，B≤0.006％，Cu≤0.10％，Ca≤0.005％，N≤0.01％，O≤0.003％，Fe余量。
PCT/CN2020/078718 2019-08-28 2020-03-11 一种高铌高温合金大尺寸铸锭的冶炼工艺及高铌高温合金大尺寸铸锭 WO2021036225A1 (zh)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP20771183.9A EP4023779A4 (en) 2019-08-28 2020-03-11 MELTING PROCESS FOR NIO-RICH LARGE HIGH-TEMPERATURE ALLOY CASTING BLOCK AND NIO-RICH LARGE HIGH-TEMPERATURE ALLOY CASTING BLOCK
US17/033,959 US11859262B2 (en) 2019-08-28 2020-09-28 Large-sized high-Nb superalloy ingot and smelting process thereof

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201910803960.4A CN111876649B (zh) 2019-08-28 2019-08-28 一种高铌高温合金大尺寸铸锭的冶炼工艺及高铌高温合金大尺寸铸锭
CN201910803960.4 2019-08-28

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US17/033,959 Continuation US11859262B2 (en) 2019-08-28 2020-09-28 Large-sized high-Nb superalloy ingot and smelting process thereof

Publications (1)

Publication Number Publication Date
WO2021036225A1 true WO2021036225A1 (zh) 2021-03-04

Family

ID=73153787

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/078718 WO2021036225A1 (zh) 2019-08-28 2020-03-11 一种高铌高温合金大尺寸铸锭的冶炼工艺及高铌高温合金大尺寸铸锭

Country Status (2)

Country Link
CN (1) CN111876649B (zh)
WO (1) WO2021036225A1 (zh)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113249584A (zh) * 2021-04-02 2021-08-13 中国航发成都发动机有限公司 一种航空发动机涡轮叶片用合金返回料重利用方法
CN114226610A (zh) * 2021-11-22 2022-03-25 钢铁研究总院 一种大规格高温合金铸锭的开坯方法及制得的棒材
CN114273642A (zh) * 2021-11-11 2022-04-05 中钢集团邢台机械轧辊有限公司 一种电渣重熔过程熔速控制方法
CN114540699A (zh) * 2022-02-28 2022-05-27 江苏宏晟模具钢材料科技有限公司 一种高性能热作模具钢及其制备方法
CN114672676A (zh) * 2022-04-02 2022-06-28 西部钛业有限责任公司 一种r60705锆合金铸锭的制备方法
CN115058629A (zh) * 2022-06-29 2022-09-16 中航上大高温合金材料股份有限公司 一种高返回料使用比例的gh2026合金冶炼工艺
CN115109986A (zh) * 2022-07-11 2022-09-27 中国铁建重工集团股份有限公司 一种大尺寸电渣重熔高锰钢锻坯及其制造方法
CN115216637A (zh) * 2022-07-25 2022-10-21 西安钢研功能材料股份有限公司 精密可伐合金箔材用合金锭的制备方法
CN115418489A (zh) * 2022-08-31 2022-12-02 重庆大学 电渣重熔含硼高温合金精确控制硼的方法
CN115537603A (zh) * 2021-06-30 2022-12-30 宝武特种冶金有限公司 一种耐高温镍基合金、其制造方法及应用
CN115612949A (zh) * 2022-10-13 2023-01-17 大冶特殊钢有限公司 一种高钛铝含量的铁镍基合金大锭坯及其冶炼方法
CN115786830A (zh) * 2022-11-09 2023-03-14 抚顺特殊钢股份有限公司 一种高合金比难变形高温合金电极坯退火工艺
CN116136007A (zh) * 2021-11-17 2023-05-19 江苏新华合金有限公司 一种钴基高温合金丝材及其制备方法
CN116380599A (zh) * 2023-06-06 2023-07-04 江苏省沙钢钢铁研究院有限公司 一种大尺寸非金属夹杂物的制备方法及其应用
CN116904756A (zh) * 2023-07-21 2023-10-20 中国科学院金属研究所 真空自耗重熔用电极组件及真空自耗重熔方法
CN117363913A (zh) * 2023-12-08 2024-01-09 成都先进金属材料产业技术研究院股份有限公司 一种低碳高铝含铌钴基高温合金及其制备方法

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112267029B (zh) * 2020-09-01 2022-09-20 钢铁研究总院 一种高铝钛的镍基合金电渣锭控制元素烧损的冶炼方法
CN112779429A (zh) * 2020-12-25 2021-05-11 国工恒昌新材料沧州有限公司 一种用电渣法设备铍铜电渣铸锭的方法
CN112880537B (zh) * 2021-01-14 2021-12-03 东北大学 一种测量真空电弧重熔过程电弧空间分布的装置及方法
CN113444889A (zh) * 2021-05-19 2021-09-28 重庆材料研究院有限公司 一种使镍基合金电渣锭的铝钛分布均匀的方法
CN116043043A (zh) * 2021-10-28 2023-05-02 宝武特种冶金有限公司 一种高温合金的四联冶炼工艺
CN113999982B (zh) * 2021-11-03 2022-08-02 钢铁研究总院 Gh4169合金铸锭的冶炼工艺
CN114540731B (zh) * 2022-02-23 2022-09-20 北京钢研高纳科技股份有限公司 一种gh4169合金棒材及其制备方法和紧固件
CN115228964B (zh) * 2022-06-15 2024-03-26 江苏银环精密钢管有限公司 核反应堆压力容器密封圈用镍基合金小口径管的制造方法
CN115491615B (zh) * 2022-08-31 2024-05-17 四川六合特种金属材料股份有限公司 一种高温合金大规格自耗锭及其制备方法
CN115852186B (zh) * 2022-12-21 2023-10-27 四川钢研高纳锻造有限责任公司 一种控制返回料添加量细化gh4169合金中碳氮化物的方法
CN117363960B (zh) * 2023-12-08 2024-03-08 成都先进金属材料产业技术研究院股份有限公司 一种低碳无铝高铌铁基高温合金及其制备方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1165205A (zh) * 1995-11-17 1997-11-19 亚瑞亚·勃朗勃威力有限公司 一种由铁-镍超级高温合金组成的耐高温材料体的制造方法
US20020170386A1 (en) 2001-03-08 2002-11-21 Bond Betsy J. Large diameter ingots of nickel base alloys
WO2013089218A1 (ja) * 2011-12-15 2013-06-20 独立行政法人物質・材料研究機構 ニッケル基耐熱超合金
CN106676299A (zh) * 2016-12-29 2017-05-17 西部超导材料科技股份有限公司 一种提高GH4720Li合金W元素成分均匀性的方法
DE102018009375A1 (de) * 2017-12-04 2019-06-06 Vdm Metals International Gmbh Verfahren zur Herstellung einer Nickel-Basislegierung

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104561664A (zh) * 2014-12-09 2015-04-29 抚顺特殊钢股份有限公司 一种新型镍铁基高温合金gh4169d的冶炼工艺
US9765416B2 (en) * 2015-06-24 2017-09-19 Ati Properties Llc Alloy melting and refining method
CN108441705B (zh) * 2018-03-16 2020-06-09 中国航发北京航空材料研究院 一种高强度镍基变形高温合金及其制备方法
CN110004312B (zh) * 2019-05-09 2020-10-27 西安聚能高温合金材料科技有限公司 一种镍基高温合金gh4698大规格铸锭的三联冶炼工艺

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1165205A (zh) * 1995-11-17 1997-11-19 亚瑞亚·勃朗勃威力有限公司 一种由铁-镍超级高温合金组成的耐高温材料体的制造方法
US20020170386A1 (en) 2001-03-08 2002-11-21 Bond Betsy J. Large diameter ingots of nickel base alloys
CN1503850A (zh) * 2001-03-08 2004-06-09 ATI�ʲ���˾ 大直径镍基合金铸块的制造方法
WO2013089218A1 (ja) * 2011-12-15 2013-06-20 独立行政法人物質・材料研究機構 ニッケル基耐熱超合金
CN106676299A (zh) * 2016-12-29 2017-05-17 西部超导材料科技股份有限公司 一种提高GH4720Li合金W元素成分均匀性的方法
DE102018009375A1 (de) * 2017-12-04 2019-06-06 Vdm Metals International Gmbh Verfahren zur Herstellung einer Nickel-Basislegierung

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
SCHOLZ, H.; BIEBRICHER, U.; BRUCKMANN, G.; ESSER, D.: "ESR Meets the Requirements for Big Forgings", IRON & STEEL, vol. 48, no. 10, 14 October 2013 (2013-10-14), pages 82 - 87, XP009526405, DOI: 10.13228/j.boyuan.issn0449-749x.2013.10.015 *

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113249584B (zh) * 2021-04-02 2022-09-13 中国航发成都发动机有限公司 一种航空发动机涡轮叶片用合金返回料重利用方法
CN113249584A (zh) * 2021-04-02 2021-08-13 中国航发成都发动机有限公司 一种航空发动机涡轮叶片用合金返回料重利用方法
CN115537603A (zh) * 2021-06-30 2022-12-30 宝武特种冶金有限公司 一种耐高温镍基合金、其制造方法及应用
CN115537603B (zh) * 2021-06-30 2023-08-11 宝武特种冶金有限公司 一种耐高温镍基合金、其制造方法及应用
CN114273642A (zh) * 2021-11-11 2022-04-05 中钢集团邢台机械轧辊有限公司 一种电渣重熔过程熔速控制方法
CN114273642B (zh) * 2021-11-11 2023-10-20 中钢集团邢台机械轧辊有限公司 一种电渣重熔过程熔速控制方法
CN116136007A (zh) * 2021-11-17 2023-05-19 江苏新华合金有限公司 一种钴基高温合金丝材及其制备方法
CN114226610A (zh) * 2021-11-22 2022-03-25 钢铁研究总院 一种大规格高温合金铸锭的开坯方法及制得的棒材
CN114226610B (zh) * 2021-11-22 2022-10-14 钢铁研究总院 一种大规格高温合金铸锭的开坯方法及制得的棒材
CN114540699A (zh) * 2022-02-28 2022-05-27 江苏宏晟模具钢材料科技有限公司 一种高性能热作模具钢及其制备方法
CN114540699B (zh) * 2022-02-28 2022-12-13 江苏宏晟模具钢材料科技有限公司 一种高性能热作模具钢及其制备方法
CN114672676A (zh) * 2022-04-02 2022-06-28 西部钛业有限责任公司 一种r60705锆合金铸锭的制备方法
CN115058629A (zh) * 2022-06-29 2022-09-16 中航上大高温合金材料股份有限公司 一种高返回料使用比例的gh2026合金冶炼工艺
CN115109986B (zh) * 2022-07-11 2023-10-10 中国铁建重工集团股份有限公司 一种大尺寸电渣重熔高锰钢锻坯及其制造方法
CN115109986A (zh) * 2022-07-11 2022-09-27 中国铁建重工集团股份有限公司 一种大尺寸电渣重熔高锰钢锻坯及其制造方法
CN115216637B (zh) * 2022-07-25 2024-05-03 西安钢研功能材料股份有限公司 精密可伐合金箔材用合金锭的制备方法
CN115216637A (zh) * 2022-07-25 2022-10-21 西安钢研功能材料股份有限公司 精密可伐合金箔材用合金锭的制备方法
CN115418489A (zh) * 2022-08-31 2022-12-02 重庆大学 电渣重熔含硼高温合金精确控制硼的方法
CN115612949A (zh) * 2022-10-13 2023-01-17 大冶特殊钢有限公司 一种高钛铝含量的铁镍基合金大锭坯及其冶炼方法
CN115612949B (zh) * 2022-10-13 2024-05-28 大冶特殊钢有限公司 一种高钛铝含量的铁镍基合金大锭坯及其冶炼方法
CN115786830A (zh) * 2022-11-09 2023-03-14 抚顺特殊钢股份有限公司 一种高合金比难变形高温合金电极坯退火工艺
CN116380599A (zh) * 2023-06-06 2023-07-04 江苏省沙钢钢铁研究院有限公司 一种大尺寸非金属夹杂物的制备方法及其应用
CN116380599B (zh) * 2023-06-06 2023-08-11 江苏省沙钢钢铁研究院有限公司 一种大尺寸非金属夹杂物的制备方法及其应用
CN116904756A (zh) * 2023-07-21 2023-10-20 中国科学院金属研究所 真空自耗重熔用电极组件及真空自耗重熔方法
CN117363913A (zh) * 2023-12-08 2024-01-09 成都先进金属材料产业技术研究院股份有限公司 一种低碳高铝含铌钴基高温合金及其制备方法
CN117363913B (zh) * 2023-12-08 2024-03-08 成都先进金属材料产业技术研究院股份有限公司 一种低碳高铝含铌钴基高温合金及其制备方法

Also Published As

Publication number Publication date
CN111876649B (zh) 2022-05-24
CN111876649A (zh) 2020-11-03

Similar Documents

Publication Publication Date Title
WO2021036225A1 (zh) 一种高铌高温合金大尺寸铸锭的冶炼工艺及高铌高温合金大尺寸铸锭
WO2021036226A1 (zh) 一种大尺寸高铌高温706合金铸锭及其冶炼工艺
US11859262B2 (en) Large-sized high-Nb superalloy ingot and smelting process thereof
CN110396605B (zh) 一种变形高温合金铸锭的制备方法
CN111519068B (zh) 一种难变形镍基高温合金gh4151合金的三联冶炼工艺
CN100366769C (zh) 大直径镍基合金铸块的制造方法
CN109112408B (zh) 大规格p92耐热钢锻件的制造方法
CN102373350B (zh) 高端轿车轮毂专用铝硅镁合金制备方法
CN111663064B (zh) 一种铸造高温合金及其熔炼方法
CN103255351B (zh) 一种高均质大规格超高强度钢锭及其制造方法
CN113999982B (zh) Gh4169合金铸锭的冶炼工艺
CN114000052A (zh) 高压锅炉管用钢p92模铸圆锭及其冶炼工艺
CN111455219A (zh) 用于镍基合金的电子束冷床炉熔炼方法
CN114635058A (zh) 一种镍基高温合金电渣锭及其制造方法
CN113122741A (zh) 一种bt22钛合金的新型制备工艺
CN109252084B (zh) 一种高纯净gh825合金细晶板材的制备工艺
CN112961989B (zh) 一种低碳高铝钢及其电渣生产方法
CN116422853B (zh) 一种模具钢及其连铸生产方法
CN104109760A (zh) 钢锭的中频感应炉电渣炉双联冶炼系统、冶炼方法及钢锭
CN116904776A (zh) 一种高合金化镍基变形高温合金Φ508mm规格铸锭开裂缺陷的控制方法
CN111139364A (zh) 一种40吨以上9Ni大型钢锭的制造方法
JPH0559483A (ja) 商用周波数帯トランス用非晶質合金薄帯の製造方法
CN110284014A (zh) 一种蒙乃尔合金的冶炼方法
CN102517476B (zh) 一种减小疏松和缩松的高强度铝合金及其制备方法
CN108950134A (zh) 冷轧辊用电渣锭的重熔方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20771183

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2020771183

Country of ref document: EP

Effective date: 20220328