Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F9/00—Making metallic powder or suspensions thereof
  • B22F9/02—Making metallic powder or suspensions thereof using physical processes
  • B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
  • B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
  • B22F9/10—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying using centrifugal force
• • 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

• a device for producing metal powders by centrifugal atomization A device for producing metal powders by centrifugal atomization.
• the invention relates to metallurgy, in particular to the production of metal powders by centrifugal spraying.
• a device for producing powders by the method of centrifugal spraying including a source for obtaining a melt in the form of an induction melting crucible, an intermediate funnel that forms a melt stream with a certain flow rate, an atomizer in the form of a bowl-shaped disk with a rotary motion drive, which are together placed in a sealed chamber filled with inert gas (The article "Development of an installation for the production of granules by centrifugal atomization of the melt", ed. By V. N. Karinsky and others, edited by A. F. Belov, issue 2, Moscow 1984, pp. 242-256).
• the disadvantage of this device is the instability of the spraying process caused by the formation of crust (scalding) on the surface of the spray disc.
• the imbalance of the masses which occurs in this case, leads to the formation of "detachments” - large particles of the garnish breaking off from the disk and frequent breakdowns due to strong vibration.
• the device does not allow obtaining powders of refractory and reactive metals due to their inevitable interaction with the crucible material.
• a device for producing powder by the method of centrifugal atomization is known - an installation of the UCR-2 type (article "Installation for producing powders by the method of centrifugal atomization of a rotating workpiece", ed. Kononov IA and others in the collection "Metallurgy of granules” edited by A. Belov. F. issue 2, Moscow, 1984. pp. 242-250).
• the device includes a chamber with a storage device for workpieces, a device for feeding them piece by piece for spraying, drives for the rotational and translational movement of the workpiece and plasmatron directed to the end face of the sprayed workpiece.
• the chamber of the installation is equipped with a material pipeline with a powder receiver, and all the elements of the installation are interconnected and form a common sealed space filled with an inert gas atmosphere.
• the disadvantage of the device is the low yield of a suitable product due to the large remainder of the workpiece (cinder), which cannot be sprayed due to the design features of the mechanism for holding it during spraying.
• Another disadvantage of this device is the high cost of laborious machining of the workpieces, including grinding of its lateral surface due to the need to balance the workpiece rotating at a high speed.
• the installation contains a chamber with a storage device for workpieces and a device for their piecewise feeding for spraying, a chamber with a workpiece rotation mechanism in the form of two driven support drums with a pressure roller and a workpiece longitudinal feed mechanism with a pusher, a melting chamber with a plasmatron directed to the end face of the workpiece being sprayed.
• the chamber with the storage of the blanks is equipped with a sluice that separates it from the chamber with the mechanisms of rotation and longitudinal feed of the blank.
• the melting chamber is equipped with a gas recirculation unit, which includes a fan, a refrigerator and traps for freezing moisture.
• the plasmatron is equipped with a mechanism for moving in the longitudinal and transverse directions relative to the workpiece, as well as a device for controlling the gap between the end of the workpiece and the plasmatron.
• the supporting drums of the workpiece rotation mechanism are equipped with vibration-absorbing rings in contact with the workpiece, and the pusher of the longitudinal feed mechanism is made in the form of a pressure roller with a flange.
• the disadvantage of the device is the high cost of labor-intensive machining of the workpieces, including grinding of its lateral surface due to the need to ensure the balance of the workpiece rotating at a high speed.
• the closest is the device (RF Patent 2467835, MGPS B22F9 / 10, 9/14, publ. 2012).
• the device includes a chamber with a storage device for workpieces and a manipulator for their piecewise feeding for spraying, drives for rotational and translational motion of the workpiece, a spraying chamber with a plasma torch directed to the end face of the workpiece being sprayed, a powder receiver, all of which are interconnected, while the rotary motion drive is made in the form of a hollow vertical spindle with an annular bowl-shaped disc at the upper end with clamping jaws located directly under the disc, and the drive for translational motion of the workpiece is made in the form of a pusher located under the spindle coaxially with it, while the axial lines of the spraying chamber, plasmatron and spindle coincide , and the annular disk is made of a heat-resistant material wetted by the workpiece material and is equipped with ventilating blades from below.
• the disadvantages of this device include the complexity of balancing the atomizer, which limits the speed of its rotation and, consequently, the possibility of obtaining fine powders.
• the device does not allow obtaining powders of refractory and chemically active metals due to the interaction of the melt with the material of the atomizer disk, and also requires high energy consumption when melting the workpiece with a plasma jet.
• the objective of the invention is to develop a device design that expands the technological capabilities of the device when producing powders of refractory and reactive metals and their alloys, as well as to expand the range of sizes of the obtained powders (obtaining finer powders in size), increase productivity and reduce energy consumption.
• the technical result is to expand the technological capabilities of the device when producing powders of refractory and reactive metals and their alloys, expanding the range of sizes of powders obtained, increasing productivity and reducing energy consumption.
• a device for producing metal powders by centrifugal spraying of workpieces including a sealed chamber with a plasmatron located along its axis in the upper part, and it contains a sprayer equipped with a rotation mechanism with a spray disk fixed on it in the form of a cooled spray disk, translational and rotary motion drives two workpieces located opposite each other to ensure that the workpieces are introduced into the plasma jet above the center of the atomizing disk with the intersection of the axis of rotation of the atomizer at the point between the plasmatron and the disk at an angle of 70 - 80 degrees to the vertical, while the workpieces are isolated from the structural elements of the device and connected to the source alternating current.
• the installation includes a sealed spray chamber (1) with a plasmatron (2) located along its axis in the upper part, a rotation mechanism (8) of the sprayer with a cooled spray disk (7) attached to the upper end of the shaft.
• a rotation mechanism (8) of the sprayer with a cooled spray disk (7) attached to the upper end of the shaft.
• two drives (5) of the translational and rotational motion of the blanks (6) into the spraying zone are placed towards each other.
• the sprayed workpieces (6) are isolated from the chamber by insulators (4) and connected to alternating current sources (3).
• containers (9) are connected to collect the powder.
• the workpieces are fixed in the drives (5) of the translational and rotational motion of the workpieces (6), the chamber (1) of the installation is sealed and evacuated. After pumping out, the chamber (1) of the installation is filled with an inert gas and the system of water cooling of the walls of the chamber (1), the plasmatron (2), the mechanism of rotation (8) of the atomizer and drives (5) are switched on. Next, the spray disc (7) is rotated at the required speed and the plasmatron (2) is turned on. An alternating voltage is applied to the workpieces (6), they are brought into slow rotation (several revolutions per minute) and introduced into the plasma jet above the center of the rotating spray disk (7).
• An electric arc ignites in the plasma flow between the workpieces (6), under the action of which the workpiece material (b) melts and the melt under the action of gravity and the pressure of the plasma jet enters the center of the rotating cooled disk (7).
• the dynamic effect of the plasma jet ensures a uniform flow of the melt onto the rotating spray disc (7) in the form of small drops, which contributes to good wetting and uniform distribution of the melt over its surface.
• the melt under the action of centrifugal force moves over the surface of the cooled disk (7) and partially crystallizes, forming a scallop that prevents the melt from interacting with the disk material (7).
• the thickness of the skull is determined by the condition of thermal equilibrium on the disk surface (7) and is determined by the amount of heat supplied with the molten metal from the plasma jet.
• the presence in the proposed device of two independent heat sources provides effective regulation of heat fluxes to maintain the required thickness of the skull and the stability of the spraying process.
• the melt Moving along the surface of the skull, the melt reaches the edge of the spray disc (7) and is sprayed with the formation of drops, the size of which depends on the rotation speed and the diameter of the spray disc (7).
• the melt droplets crystallize in flight until impact on the wall of the chamber (1), and are collected in the receiving hopper (9) located in the lower part of the chamber (1).
• the sprayed workpieces are not connected with the mechanism of rotation of the spray disc, which makes it possible to reduce the imbalance and thereby significantly increase its rotation speed.
• Expansion of the range of possible rotation speeds of the atomizer with a spray disc makes it possible to obtain powders in a wide range of particle sizes, including finely dispersed ones.
• the intersection angle and slow rotation of the workpieces ensure uniform melting of the workpiece ends and flow of the melt into the center of the spray disc.
• the location of the plasmatron over the point of intersection of the workpieces ensures the stabilization of the electric arc combustion, the uniformity of the flow rate of the melt and the transfer of the melt to the center of the spray disk in the form of small drops, which stabilizes the spreading of the melt over the surface of the spray disk.
• the plasma jet from the plasmatron directs the plasma flow of the electric arc burning between the ends of the blanks to the surface of the spray disk, providing additional heating of its surface and stabilization of the skull.
• the frequency of rotation of the atomizer with a 080 mm disc was varied in the range of 20,000-30,000 min-1, while a powder with a particle size in the range of 80-30 microns was obtained. Thus, the range of powder size is shifted towards smaller fractions. Due to the interaction of the spray disc with the titanium melt, it is impossible to obtain titanium powders at the prototype installation.
• the design of the device has been developed, which provides an expansion of the technological capabilities of the device when obtaining powders of refractory and reactive metals and their alloys, as well as expanding the range of sizes of the powders obtained, increasing productivity and reducing energy consumption.

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• Manufacture Of Metal Powder And Suspensions Thereof (AREA)
• Coating By Spraying Or Casting (AREA)

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• 2020
  • 2020-02-19 RU RU2020107387A patent/RU2742125C1/ru active
  • 2020-11-10 WO PCT/RU2020/000593 patent/WO2021167487A1/ru active Application Filing
  • 2020-11-10 CN CN202080094796.5A patent/CN115135435B/zh active Active

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