46 results about "Vacuum arc remelting" patented technology

The invention belongs to the technical field of research and development of fast neutron reactor jackets and structural materials, and particularly relates to a high-temperature-lead-bismuth-corrosion-resistant high-silicon-content ferrite / martensite steel ladle tube and a preparation method thereof. According to the mass percentage, the composition mainly comprises the following components: 0.16-0.24% of C; 0.4 to 0.8 percent of Mn; cr: 11.6% to 12.4%; 1.2 to 1.8 percent of W; 0.1 to 0.4 percent of Ta; 0.2 to 0.4 percent of V; 1.0%-1.8% of Si and Fe. The preparation method comprises the steps of vacuum induction and vacuum arc remelting. Carrying out homogenization treatment and forging; extruding and annealing; cold rolling and annealing; and performing normalizing and tempering treatment. Through an efficient short-flow process route and reasonable smelting, pipe machining deformation and heat treatment processes, the microscopic structure of the material is remarkably improved, then the mechanical property and high-temperature lead and bismuth corrosion resistance of the finished pipe are improved, and the use requirement of the lead and bismuth cooling fast reactor fuel assembly cladding material under the high-temperature working condition is met.

An electrode assembly for vacuum arc remelting, comprising a primary electrode (1) and a dummy electrode (2). The primary electrode (1) is a vacuum arc remelting electrode; one end of the primary electrode (1) is provided with a shrinkage cavity (3); the dummy electrode (2) is connected to the end of the primary electrode (1) with the shrinkage cavity (3) by means of soldering; an insulating material (4) is provided between the dummy electrode (2) and the primary electrode (1) with the shrinkage cavity (3); and the insulating material (4) covers the shrinkage cavity (3) of the primary electrode (1). By using the electrode assembly, the production cost of vacuum arc remelting ingots can be reduced, and a good inclusion level can be obtained.

The present invention relates to the technical field of other processing of metals. Disclosed are a free-machining titanium material and a preparation process therefor. The free-machining titanium material comprises: a matrix component group and free-machining component groups, wherein at least one of the free-machining component groups is added to the matrix component group; the matrix component group comprises the following components in percentage by mass: 0-1.0% of Fe, 0-0.08% of N, 0-0.02% of H, 0-0.50% of O, 0-8.0% of Al, 0-15.0% of V, and the balance being titanium and inevitable impurities; and the free-machining component groups are an RE element and S element group, a Cu element and S element group, a Zr element group, a C element group, a B element group, and an Mg element group, respectively. The preparation process involves producing the described free-machining titanium material by using any one of the following three methods: vacuum arc remelting, vacuum floating melting, and powder metallurgy. The present invention solves the technical problem of how to further improve the machinability of titanium materials.

A vacuum induction smelting method for high-purity stainless steel, the method comprising: adding a high-purity return material at the last stage of smelting, the addition amount of the high-purity return material being not less than the weight of molten steel contained under the condition that the height of a crucible for smelting is 100 mm, the high-purity return material being high-purity stainless steel cut blocks or cleaned and briquetted turnings smelted by a duplex process of vacuum induction smelting plus vacuum arc remelting, and the O content of the return material being ≤10ppm. The method reduces the metal material loss caused by incapability of melting metal rings into molten pools under conventional conditions, such that the stainless steel smelting yield in vacuum induction smelting stages reaches 98% or above. The method reuses high-purity return materials obtained after VIM+VAR, and avoids the formation of metal rings, thus avoiding the molten steel loss of 2-4%, raising the yield of molten steel in vacuum induction smelting stages, and effectively reducing the production cost of high-purity stainless steel without lowering the purity of the stainless steel.

A vacuum arc remelting (VAR) system for forming an ingot from an electrode includes a crucible configured to accommodate the electrode and the ingot, one or more electromagnetic energy sources arranged about the crucible, and a controller configured to provide electric current to the one or more electromagnetic energy sources and adjust the electric current through the one or more electromagnetic energy sources. The adjustment of the electric current is based on an approximation of a thickness of a shelf, wherein the shelf is formed based on an accumulation of debris on an inner periphery of the crucible.

The invention belongs to the technical field of stainless steel, and particularly relates to aluminum oxide inclusion refined low-oxygen low-sulfur stainless steel and a preparation method thereof. The method sequentially comprises the steps of AOD primary smelting, LF furnace external refining, die casting and pretreatment, VIM vacuum induction smelting, VAR vacuum consumable remelting and forging, and precise regulation and control of inclusion types and element impurities are achieved by limiting aluminum source input of all stages, introducing a magnesium treatment mechanism and utilizing a vacuum deoxidation technology. The process is simple and efficient, the cleanliness and service performance of the stainless steel can be remarkably improved, and the method is particularly suitable for the field of semiconductor and high-end equipment manufacturing with strict impurity control requirements.

This invention discloses a smelting method for large-size Fe-based superalloys for gas turbines, comprising two steps: casting metal raw materials into 710mm electrode rods in a vacuum induction furnace, and then remelting the electrode rods in a vacuum arc remelting furnace to produce 810mm steel ingots. This invention employs a combined vacuum induction melting and vacuum arc remelting (VIM+VAR) process, which effectively controls Ti element burn-off to ensure its content meets standards, and avoids excessive formation of Ti-based carbonitrides, fundamentally mitigating the negative impact on the purity of the molten steel.

The present invention relates to remelting plants for metals, such as vacuum arc furnaces (vacuum arc remelting, VAR) and electro slag remelting plants (electro slag remelting, ESR), which have one or more melting locations. The plants have a uniformly low overall height and allow weighing with the highest precision. For this purpose, they are provided with a non-coaxially driven electrode rod (140) and a weighing device (230, 240) arranged laterally. The electrode is centered without generating transverse forces which have a negative influence on the plant structure and the weighing result.

The purpose of the present invention is to provide a high-purity invar alloy, which is the material of a fine metal mask. One implementation of the present invention provides a method for manufacturing a high-purity iron-nickel alloy, comprising the steps of: preparing iron-nickel alloy scrap; forming a melting pool through electron beam cold hearth melting of the iron-nickel alloy scrap; preferably after the melting pool formation step, proceeding with a 1.5-2.5 ratio (kW / kg) of an electron beam output to the weight of a material so as to form a melting pool temperature of 1,800°C or higher, thereby melting and evaporating non-metallic inclusions in the molten pool; performing vacuum induction melting on the alloy in which the non-metallic inclusions have been melted and evaporated, thereby providing a vacuum induction-melted alloy; and performing vacuum arc remelting on the vacuum induction-melted alloy, wherein the number of inclusions having a size of 2 μm or greater in the manufactured alloy is 5.0 / mm2 or less, and preferably, 4.0 / mm2 or less.

The application relates to a titanium product processing device for a vacuum consumable arc furnace and belongs to the technical field of titanium product processing. The device comprises a base, the base is a hollow structure, the top outer wall of the base is fixedly connected with a rack, the top of the rack is provided with a mounting seat, the bottom of the mounting seat is provided with a cutting machine for cutting titanium products; the application also discloses a processing method. The two water tanks are arranged, and the inclination of the U-shaped pipe is matched, so that the two water tanks are alternately used, two different use states of cutting fluid collection and cutting fluid feeding are achieved, the cutting fluid is preliminarily cooled, the consumption of the later-stage refrigerant is reduced, and the production cost is reduced. The driving motor is started to simultaneously realize stirring cooling and bidirectional air cooling of the cutting fluid, the cutting fluid in the two water tanks can be cooled, and the cooling effect is greatly improved. The whole operation is simple, and the cooling effect is good.

The invention discloses a preparation method of a rare earth-containing high-purity high-temperature alloy. The preparation method comprises the following steps: carrying out surface shot blasting pretreatment on an alloy matrix raw material; coating the high-purity rare earth metal particles with nickel / cobalt foil, and preheating in a vacuum environment; a duplex vacuum melting process is adopted, firstly, matrix raw materials are smelted in a vacuum induction furnace, refining and degassing are conducted, then preheated rare earth particles are added under the synergistic effect of inert gas protection and an ultrasonic field, and the rare earth particles are rapidly melted and dispersed through electromagnetic stirring; and after the raw materials are poured into ingots through a slag stopping and filtering system, vacuum arc remelting is carried out, and the high-purity and low-segregation rare-earth-containing high-temperature alloy master alloy is finally obtained in cooperation with a cyclone separation technology. Through the multi-stage synergistic process of raw material pretreatment, rare earth coating preheating, ultrasonic electromagnetic synergistic dispersion and duplex smelting staged purification, the yield of the rare earth elements is remarkably increased, the oxygen content of the alloy is controlled to be smaller than or equal to 7 ppm, and highly uniform distribution of the rare earth elements in the alloy is achieved.

The invention discloses a vacuum arc remelting furnace, and relates to the technical field of arc melting furnaces, the vacuum arc remelting furnace comprises a lower base used for supporting the vacuum arc remelting furnace, a main support is fixedly mounted on the lower base, a melting furnace shell is slidably mounted on the main support, and a lower electrode is slidably mounted in the melting furnace shell; a closed box is installed at the end, away from the lower base, of the smelting furnace shell in a contact mode, a closed cover is fixedly installed in the closed box, the closed cover, the smelting furnace shell and the lower electrode form a furnace chamber, a flowing outlet is further fixedly installed at the end, close to the closed cover, of the smelting furnace shell, and one end of the flowing outlet leads to the interior of the furnace chamber. According to the device, the storage size of the furnace chamber is changed by adjusting the position of the lower electrode, metal materials of different components can be smelted through the device, a metal solution flows out of the device through movement of the smelting furnace shell, and therefore the device can be used for smelting metal materials of different components. Therefore, high-temperature waste residues at the bottom of the furnace chamber can be separated from a metal solution, and the quality of smelted metal is improved.

The invention discloses a vacuum arc remelting method for nitrogen-containing stainless steel with the nitrogen content of an electrode being about 0.05%, the concentration of N2 between the electrode and a molten pool is reduced through short arc control, and melting parameter fluctuation caused by glow discharge is eliminated, so that the solidification defect is avoided. In the steady state and filling stage, inert gas argon is filled into the furnace, the vacuum degree in the furnace is reduced, volatilization and escape of N in molten steel are restrained to a certain extent, and the N content of the molten steel is larger than or equal to 0.02% according to the technical standard requirement.

A control system includes a vision system including an imaging device and a VAR monitoring system configured to determine a power adjustment phase of the VAR process based on the images from the vision system and a process parameter. The VAR monitoring system includes a vision analysis module configured to analyze the images from the vision system to detect a melt marker based on a remelt image process model, and a prediction module configured to predict an operational characteristic of the VAR process that is associated with the power adjustment relative to a melt marker location and a remelt prediction model. The VAR monitoring system is configured to initiate the power adjustment phase in response to the melt marker satisfying a predetermined melt marker condition, the operational characteristic of the VAR process satisfying a predetermined operational condition, or a combination thereof.

A vacuum arc remelting system for forming an ingot from an electrode is provided, the system including a crucible assembly configured to receive the electrode and the ingot; an electromagnetic energy source disposed around the crucible assembly; and a lifting mechanism operable to move the electromagnetic energy source along the longitudinal axis of the crucible assembly. During remelting, a magnetic field generated by the electromagnetic energy source is confined to an arc zone, and in one form, the electromagnetic energy source is a coil assembly having a magnetic core and a plurality of coil pairs wound around the magnetic core, where the coil assembly is operable to generate a magnetic field from the coil based on a current flowing in the plurality of coil pairs.

A vacuum arc remelting (VAR) system for forming an ingot from an electrode is disclosed. The system includes a crucible assembly configured to accommodate the electrode and the ingot. The system includes a primary electromagnetic energy source arranged about the crucible assembly. The primary electromagnetic energy source and the crucible assembly are configured to move relative to one another along a longitudinal axis of the crucible assembly. The system includes a secondary electromagnetic energy source arranged about an upper end portion of the crucible assembly. The secondary electromagnetic energy source is stationary and fixed to the upper end portion of the crucible assembly.

The application discloses a kind of multi-scale simulation methods of vacuum self-consumption electric arc smelting process ingot, it is related to metal smelting technical field, including: based on the actual working condition parameters and material thermal physical parameters of vacuum self-consumption electric arc smelting, the three-dimensional geometric model of smelting area is established and function area is divided;Multi-physics field coupling numerical model is constructed in macroscopic simulation software, and simulation calculation result is obtained;Simulation result is input to mesoscopic simulation software through standardized data interface, as the initial condition and boundary condition of mesoscopic scale simulation, based on phase field model and solute diffusion equation, the grain growth morphology, solute distribution and microstructure evolution process are simulated;Crystal growth rate, solidification rate and solute distribution result are fed back to multi-physics field coupling numerical model, and iterative calculation is carried out, to realize the closed loop coupling of macroscopic and mesoscopic simulation.The application realizes the accurate control of ingot microstructure and performance.

The invention discloses a neodymium iron boron magnetic powder preparation device, and belongs to the field of neodymium iron boron magnetic powder preparation. The device comprises a vacuum arc remelting rapid quenching furnace, wherein the vacuum arc remelting rapid quenching furnace comprises an arc remelting device, an overflow liquid guide mechanism, a rapid quenching powder making device and an auxiliary system; the overflow liquid guide mechanism comprises a liquid guide assembly, and the liquid guide assembly comprises a conical flow guide opening, a ceramic filter element, an electromagnetic flow valve and a flow guide groove; the rapid quenching powder making device comprises a cooling rotating wheel, a driving assembly and a magnetic powder collecting assembly. Meanwhile, floating and settling impurities in the melt are filtered through the arrangement of the filtering assembly, the melt entering the rapid quenching device is prevented from containing the impurities, the uniformly flowing melt is cooled through the arrangement of the cooling rotating wheel in the rapid quenching device, the melt is uniformly cooled and pulverized through the rapid quenching device, a fine grain structure is formed, and the quality of the melt is improved. The thermal expansion rate of the magnetic powder is reduced; and the characteristics of low expansion and high magnetic performance of the magnetic powder are ensured.

This invention relates to the field of high fatigue strength titanium alloy technology, specifically to a method for preparing TA15 alloy bars with high fatigue strength through synergistic regulation. The method involves increasing the content of the main elements Al, Mo, V, and Zr, controlling the content of interstitial elements Fe, O, and C, and adding trace amounts of Nb to obtain a novel TA15 alloy composition. First, a 520mm TA15 alloy ingot is prepared by three vacuum arc remelting processes. Next, the TA15 alloy ingot is forged, and by reducing the forging temperature of the forming passes and increasing the deformation, a 180mm transfer bar is obtained. Subsequently, at the rolling temperature, by controlling the deformation between passes, the 180mm bar is rolled to a 65mm diameter in a single pass. Finally, within the range of 800-850℃, the 65mm bar is solution-treated to obtain a 65mm TA15 alloy bar. The 65mm TA15 alloy bar prepared by this invention has a uniform and fine primary α phase with a primary α phase content of 45~55%, a uniformly broken secondary α phase, and a smooth surface with a high cycle fatigue strength ≥698MPa.

The utility model relates to an automatic crucible identification device, which comprises a smelting station outer cylinder, a crucible and a travel switch, the crucible is provided with a crucible body placed in the smelting station outer cylinder and a switch beating plate ring arranged around the upper edge of the crucible body, the travel switch is arranged at the upper part of the outer wall of the smelting station outer cylinder, and the switch beating plate ring is arranged on the upper part of the outer wall of the smelting station outer cylinder. And the travel switch is provided with a contact which is vertically upwards contacted with the switch beating plate ring, and the heights of characteristic parts, which are contacted with the travel switch, of the switch beating plate ring on different crucibles are different. The switch beating plate rings used by different crucibles trigger the contacts of the travel switches to reach different strokes, so that the device can distinguish the types of the crucibles by utilizing the height of the characteristic part and output different signals to a control system, and then the operation parameters of the vacuum arc remelting furnace control system are changed, and the quality of the crucible is improved. And loss caused by mismatching of the crucible type and the steel type is avoided.

This invention relates to the field of precision alloy material processing technology, and discloses an Invar alloy precision strip for semiconductor displays, its preparation method, and applications. This invention controls sulfur content at the source and combines this with microalloying by adding 0.002–0.005 wt.% rare earth cerium (Ce) to strengthen grain boundaries and improve thermoplasticity. It innovatively employs an ultra-high purity smelting route of "vacuum induction melting (VIM) + two vacuum arc remelting (double VAR)" combined with intermediate forging to remove non-metallic inclusions such as oxides and reduce gas content, obtaining ultra-high purity ingots. Finally, through a multi-stage high-temperature diffusion forging, controlled rolling and cooling, multi-stage intermediate annealing, and precision cold rolling, a precision strip with a thickness of 0.10 mm is prepared. Through the above process, the strip prepared by this invention has extremely high purity, a uniform and fine microstructure (grain size 8–10), and excellent surface quality and shape, fully meeting the stringent requirements of semiconductor display devices for substrates.

The invention relates to the technical field of titanium alloy preparation, and discloses a method for eliminating defects at the bottom of a titanium alloy cast ingot, which comprises the following steps: placing the titanium alloy cast ingot in a crystallizer for vacuum arc remelting, and in the vacuum arc remelting process, controlling the holding time tw of the current in the arc starting stage at the melting current I to meet the formula (1); wherein the unit of tw is min, phi is the diameter of the crystallizer, and the unit is mm; i is smelting current, and the unit is kA. According to the method, the layering defect at the bottom of the cast ingot can be reduced, the cold shut defect in the cast ingot can be prevented, and the internal quality of the titanium alloy cast ingot is guaranteed.

The invention belongs to the technical field of titanium alloy material processing, and relates to a segregation-free, high-strength and large-specification Ti6Al6V2Sn titanium alloy forge piece and a preparation method thereof. The thickness of the titanium alloy forge piece manufactured through the method ranges from 350 mm to 420 mm, the width of the titanium alloy forge piece ranges from 420 mm to 470 mm, and the length of the titanium alloy forge piece ranges from 3200 mm to 4400 mm. The method comprises the specific steps that firstly, raw materials of a titanium alloy forge piece are placed in a vacuum consumable smelting furnace, and a Ti6Al6V2Sn cast ingot is prepared through multiple times of smelting; the pretreated cast ingot is sequentially subjected to cogging forging, intermediate forging and finished product forging, and then a finished product forging stock is obtained; and finally, the finished forging stock is subjected to solid solution aging heat treatment, then straightening and machining are sequentially conducted, and the Ti6Al6V2Sn titanium alloy forge piece is obtained and has good strength and plasticity comprehensive performance and can be applied to the high-end equipment manufacturing and key industrial field.

The invention discloses a high-performance niobium-titanium pipe chemical formula and preparation process research thereof. The high-performance niobium-titanium pipe chemical formula comprises the following chemical components in percentage by mass: 0.25-0.45% of Zr, 0.015-0.025% of O, less than or equal to 0.010% of N, less than or equal to 0.002% of H, less than or equal to 0.010% of C, less than or equal to 0.050% of Fe and Ni, 45.0-48.0% of Nb, the balance of Ti, the sum of Nb and Ti being 99.475-99.688%, and the balance of other unavoidable impurities. The niobium-titanium alloy pipe with high strength, high toughness, high yield and excellent corrosion resistance is prepared through the steps of vacuum induction melting, double vacuum arc remelting, hot forging, nano BN / MoS coating core rod extrusion punching, multi-pass cold drawing, intermediate vacuum annealing, solid solution-aging composite heat treatment, precise pickling passivation and the like. The process is suitable for the fields of aerospace, ocean engineering and nuclear industry.

The present invention provides a high-purity Invar alloy that can be used as a material for fine metal masks. One embodiment of the present invention includes the steps of preparing iron-nickel alloy scrap, forming a melting pool by electron beam cold hearth melting the iron-nickel alloy scrap, and preferably, after the melting pool forming step, melting and evaporating non-metallic inclusions in the melt by setting the electron beam power to material weight ratio (kW / kg) at 1.5 to 2.5 to form a melting pool temperature of 1,800°C or higher, vacuum induction melting the alloy from which the non-metallic inclusions have been melted and evaporated to provide a vacuum induction melted alloy, and vacuum arc remelting the vacuum induction melted alloy, wherein the number of inclusions 2 μm or larger in the produced alloy is 5.0 / mm. 2 Less than 4.0 pieces / mm 2 The present invention provides a method for producing a high-purity iron-nickel alloy having a purity of less than 100%.

This invention discloses an ultra-pure 316L austenitic stainless steel for semiconductor manufacturing equipment, its preparation method, and its applications, belonging to the field of special alloy smelting technology. The chemical composition of this stainless steel includes: Cr: 17.5%~18.0%; Mo: 2.5%~3.0%; Ni: 13.5%~14.0%; S ≤ 0.003%; Al ≤ 0.01%; the balance being Fe and unavoidable impurities. The preparation method employs a triple process of vacuum induction melting, electroslag remelting, and vacuum arc remelting. Vacuum induction melting uses low-sulfur pure iron; electroslag remelting uses a completely aluminum-free slag system; vacuum arc remelting achieves deep deoxidation without residue in a high vacuum; subsequently, it undergoes high-temperature diffusion treatment, forging, and hot rolling. This invention completely eliminates Class B alumina inclusions and δ-ferrite, has an oxygen content of less than 5 ppm, a finer austenitic grain size than ASTM Grade 8, and achieves a mirror finish through electrolytic polishing, meeting the requirements for semiconductor applications.

The purpose of the present invention is to provide a high-purity invar alloy which is a material for a fine metal mask. One embodiment of the present invention provides a method for manufacturing a high-purity iron-nickel alloy, comprising the steps of: preparing an iron-nickel alloy scrap; a step in which the iron-nickel alloy scrap is subjected to electron beam cold bed melting to form a melt pool; preferably, after the molten pool forming step, a step for melting and evaporating non-metallic inclusions in the molten pool by setting the ratio of electron beam power to material weight (kW / kg) to 1.5-2.5 and the molten pool temperature to 1,800 DEG C or more; a step of performing vacuum induction melting on the alloy obtained by melting and evaporating the non-metallic inclusions, so as to provide the alloy after the vacuum induction melting; and a step of vacuum arc remelting the alloy after vacuum induction melting, the number of inclusions of 2 [mu] m or more in the manufactured alloy being less than 5.0 / mm < 2 >, preferably less than 4.0 / mm < 2 >.

The present invention relates to the technical field of titanium alloys, and discloses a method for preparing an α-titanium alloy sheet having a high deformation twin density. The method comprises: adding sponge titanium, aluminum shot, titanium diboride, Ti-32Fe and titanium dioxide, which act as raw materials, into a smelting furnace, and performing three instances of vacuum arc remelting to obtain an ingot; measuring the phase transition point Tβ of a Ti-Al-B-based alloy by means of a differential thermal analysis method, and performing two-heat hot rolling on the ingot to obtain a slab; and heating the slab to a temperature of Tβ, maintaining the temperature for the first time, then cooling same with water, reheating the slab to a temperature of (Tβ-200)°C, maintaining the temperature for the second time, and then air-cooling same to room temperature, so as to obtain a sheet. In the present invention, a sheet having a high deformation twin density is prepared by, with respect to a Ti-Al-B-based α-titanium alloy, using a design involving increasing the β-stabilizing element Fe and microalloying the element, performing three instances of vacuum arc remelting, and using a three-heat hot rolling process involving direct-rolling cogging and a high deformation per pass. The structural uniformity and the strength-toughness balance of the alloy are ensured at low costs.

The present invention belongs to the technical field of alloy materials, and particularly relates to a rare-earth-containing aviation bearing steel with excellent impact toughness and a preparation method thereof. The rare-earth-containing aviation bearing steel with excellent impact toughness has the following chemical components by mass percentage: C 0.80% - 0.85%, Mn 0.15% - 0.35%, Cr 4.00% - 4.25%, Mo 4.00% - 4.50%, V 0.90% - 1.10%, RE 0.04% - 0.09%, Ni 0.10% - 0.30%, Si 0.10% - 0.30%, W 0.20% - 0.50%, Nb 0.01% - 0.02%, Al 0.01% - 0.04%, P≤0.015%, S≤0.008%, and the balance is Fe and inevitable impurities. The rare-earth-containing aviation bearing steel of the present invention is prepared by vacuum induction melting, vacuum arc remelting, homogenization annealing, hot working, spheroidizing annealing, quenching, and two tempering treatments. The content of impurity elements is low, and the heat-treated material has fewer high-temperature carbides, higher hardness, and excellent impact toughness.

This application discloses a method for controlling white spot defects and a vacuum arc remelting device, belonging to the field of vacuum arc remelting technology. Its main purpose is to achieve real-time identification of electrode shavings and to adjust the power differentially based on the size of the shavings, thereby improving the control effect of white spot defects during the vacuum arc remelting process. The main technical solution of this application is as follows: The white spot defect control method includes: acquiring vacuum arc remelting process parameters; identifying shavings and determining the equivalent size of the shavings based on the process parameters; generating control commands based on the correspondence between the equivalent size of the shavings and at least two determined critical sizes; and adjusting the melting power of the vacuum arc remelting device in response to the control commands.