RU2356696C1 - Device for receiving of metallic powder - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy field, particularly to devices for metallic powder receiving. Device contains smelting chamber with heater, connected to it mechanism chamber, blanks metering device into smelting chamber, vacuum system, inlet box, tank for powder collection and located in mechanism chamber axial movement mechanism of blanks with pusher and blank swinging mechanism with driven rolls. Blank swinging mechanism is outfitted by clamping roller and bearing assemblies with gas cooling devices, electrical insulating bush of erosion-preventive tear and wear of rolling surface of bearing assemblies, temperature control sensor and level of vibration. Driven roller and clamping roller of blank swinging mechanism are installed on bearing assembly, pusher is implemented with set of nozzles on the end, directed to the side of blank feeding. Smelting chamber and mechanism chamber are connected to each other by bypass pipeline with valve.

EFFECT: range extension of sizes of received powders and homogeneity increasing of its dimension.

3 dwg, 1 tbl

Description

The present invention relates to the field of metallurgy and can be used to obtain metal powders.

A known installation for producing metal powder, consisting of a melting chamber with a heater, a supply chamber of blanks and a piggy bank, the melting chamber is made up of two parts with a connector between them in a vertical plane, the first of which (stationary) is connected to the supply chamber of the blanks and the piggy bank, and the second (detachable) is connected with the heater (Copyright certificate for the invention of the USSR No. 820068, B22F 9/08, 1979).

The disadvantage of this installation is the low quality of the produced powder due to possible foreign inclusions and an increased content of oxides on the surface of the particles.

A known installation for producing a metal powder, comprising a melting chamber with a heater, a rotation mechanism and axial movement of the workpieces placed in an airtight housing, a workpiece dispenser, a powder receiving chamber and a powder container (USSR Author's Certificate No. 5434304, B22F 9/08, 1976 .) is a prototype.

The disadvantage of this installation is the limitation of the range of powders produced, the heterogeneity of their fractional composition.

The proposed installation for producing metal powder comprises a melting chamber with a heater, a mechanism chamber connected to it, a billet dispenser in the melting chamber, a vacuum system, a receiving chamber, a powder collecting container and axial movement of workpieces with a pusher and a workpiece rotation mechanism with drive rolls, while the rotation mechanism of the workpieces is equipped with a pressure roller and bearing bearings with gas cooling devices, electrically insulating bushings and erosion of wear of the rolling surfaces of the bearings, sensors for monitoring temperature and level of vibration, while the drive rolls and the pressure roller of the workpiece rotation mechanism are mounted on the bearings, the pusher is made with a nozzle device at the end facing the workpiece feed, and the melting chamber and the mechanism chamber are connected between themselves bypass pipe with valve.

The proposed installation differs from the prototype in that the workpiece rotation mechanism is equipped with a pressure roller and bearing bearings with gas cooling devices, electrically insulating bushings for anti-erosion wear of the bearing surfaces, temperature and vibration level sensors, while drive rolls and a pressure roller of the workpiece rotation mechanism are mounted on bearing bearings, the pusher is made with a nozzle device at the end facing the supply side of the workpiece, and the melting The camera and the camera mechanisms are interconnected by a bypass conduit with a valve.

EFFECT: expanding the range of particle sizes of the obtained powders, increasing their uniformity in fractional composition, and, as a result, expanding the assortment of products obtained from these powders with an increased level of physical and mechanical properties and, as a result, increasing the service life.

The proposed installation allows to obtain metal powders of various sizes, including ultrafine with a particle size of less than 100 microns, homogeneous fractional composition by expanding the range of rotation speed of the workpiece up to very high values, of the order of 20,000-25,000 min ^-1 . Maintenance of such a high rotational speed of the workpiece is ensured by the design features of the installation, namely, that the bearing bearings of the drive rolls of the rotation mechanism and the pressure roller, experiencing increased heating of the rubbing parts, the generation of electrostatic charges, the increased vibration frequency, are equipped with gas cooling devices, electrical insulating bushings for anti-erosion wear of surfaces rolling bearings, sensors control the temperature and level of vibration.

To reduce the wear of the pusher from friction, especially at increased speeds of rotation of the workpiece, the pusher located in the mechanism chamber is made with a nozzle device at the end facing the supply side of the workpiece. In this case, due to the gas jet leaving the nozzle, a “gas cushion” is created between the pusher and the end face of the workpiece, which sharply reduces friction and the formation of metal dust, the penetration of which into the rubbing parts of the bearing supports is prevented by the presence of a bypass pipe with a valve between the melting chamber and the mechanism chamber. The gas bypass valve can be adjusted so that a higher gas pressure is maintained in the mechanism chamber than in the melting chamber, and gas containing metal dust will flow into the melting chamber, thereby preventing dust from settling in the mechanism chamber, including in bearings.

The installation allows you to get a fine-grained structure of the particles themselves, to reduce their size and the size of impurity particles, which are almost always present in the mass of the main powder and thereby reduce their harmful effect on the mechanical properties of compact products pressed from powders. Products obtained from such powders have a higher level of physicomechanical properties (tensile strength, ductility), which allow to expand the assortment of manufactured products from them, including the use of powders for the manufacture of critical products with increased service life.

The proposed installation is illustrated by drawings, where:

- figure 1 shows a frontal section;

- figure 2 is a cross section;

- figure 3 is a top view.

The installation consists of a support 1, on which a melting chamber 2 is mounted, a mechanism chamber 3, interconnected by a flange connector 4.

The melting chamber 2 is provided with a sliding cover 5, in which a heater 6 (plasmatron) with a mechanism 7 for its working movement is installed. The walls of the melting chamber 2 and the plasma torch 6 are connected by pipelines 8 with a source of cooling water (not shown in FIGS. 1-3).

The camera of mechanisms 3 consists of a vacuum-tight housing, in the volume of which two horizontal cylindrical rolls 9 are mounted on bearings 10 with gas cooling, anti-erosion bushings on their rolling surfaces, temperature and vibration level sensors (not shown in Figs. 1-3) , with an electric drive of rotation from individual electric motors 11, a push movable roller 12 on bearing bearings of the same design as the bearings 10, placed above the rollers 9 and equipped with a mechanism 13 for pressing it against the cylinder billet resting on both rolls at the same time.

In the flange connector 4 of the cameras mounted water-cooled screen 14 with a Central hole for the workpiece. Coaxial with the workpiece is a longitudinal feed mechanism 15 with a pusher 16 and a nozzle apparatus 17.

The installation is equipped with an electrical system 18, a vacuum system and a gas system with which the nozzle apparatus 17 is connected. A workpiece dispenser (not shown in Figs. 1-3) is attached to the mechanism chamber 3, which is equipped with a workpiece feed mechanism 19 with a tray 20.

The melting chamber 2 and the mechanism chamber 3 are interconnected by bypass pipe 21 with a control valve 22.

Installation works as follows.

The start of the installation begins with the inclusion of a vacuum system for pumping air from the chambers of the installation to a given residual pressure of 0.013 Pa. When a predetermined vacuum is reached, the pumping system is turned off and the chamber cavities are filled with the working gas atmosphere (for example, inert gases) to the desired pressure.

From the billet dispenser, a workpiece 23 is fed to the rolls 9 using a feed mechanism 19 onto the rolls 9 and pressed against the rolls 9 by a pressure roller 12 by means of a longitudinal feed mechanism 15 with a pusher 16. The workpiece is moved along the rolls into the melting chamber 2 through the opening of the water-cooled screen 14 in the position at which the distance from the plane of the screen 14 to the end face of the workpiece 23 is ~ 25 ÷ 30 mm. Turn on the gas system and recycle the working gas through the chambers of the unit with its supply to the nozzle apparatus 17 of the pusher 16 to create a gas cushion between the pusher and the end face of the workpiece, bearing bearings 10 for cooling, and the valve 22 on the bypass pipe 21 is adjusted so that the gas pressure in the chamber mechanisms was higher than in the melting chamber, and gas always moved towards the melting chamber, ensuring the removal of metal dust from the mechanism chamber.

The operating speed of the rolls 9 is set, after which the arc of the plasma torch 6 is ignited, the set value of power (current and voltage) is set. The plasma torch 6 by the mechanism 7 moves to the end of the rotating workpiece at a distance of ~ 20 mm, and the process of melting and dispersion of the workpiece begins. The longitudinal feed mechanism 15 of the workpiece is turned on, and a predetermined feed (melting) feed rate is set on it and the power (current, voltage) of the plasma torch is adjusted so that the position of the end face of the workpiece 23 relative to the plasma torch 6 remains unchanged. The process of feeding the workpiece by the mechanism 15 with the pusher 16 continues until the length of the remaining (unmelted) part (cinder) reaches the minimum length that the pressure roller 12 can still reliably hold on the rolls 9. After this, the melt stops, the plasma torch 6 mechanism 7 is withdrawn from the end of the cinder, the current and voltage on the plasma torch are reduced to the minimum values that ensure stable arc burning in the plasma torch 6, the rotation of the rollers 9 is stopped, the pressure roller 12 is removed from the cinder, and the flame is reset to the chamber 2. Then, the longitudinal feed mechanism 15 is retracted to the extreme position remote from the melting chamber 2 and the next workpiece 23 is fed to the rolls 9 from the workpiece dispenser 19 and then, acting in a manner similar to that described previously for spraying the first workpiece, melting and dispersion of the second and subsequent preforms located in the loading chamber.

Comparative studies of the physical, chemical and technological properties of the granules obtained on the proposed installation and the installation of the prototype were carried out. The results of the study are shown in table 1.

Table 1 The properties of the granules obtained in the proposed spray installation and installation of the prototype No. p / p Parameter Name Suggested installation Prototype Installation one Oxygen content ≤0.005 ≤0.007 2 The size of the main fraction of the powder, microns <100 <140 3 The content in the batch of granules of the main fraction,% 92 76 four Bulk density, g / cm ³ 5.12 4.96 5 The density after shaking, g / cm ³ 5.68 5.49 * 6 Tensile strength, MPa 1450 1250 * 7 Yield Strength, MPa 1020 800 *8 Relative extension, % eighteen 13 9* Low cycle fatigue resistance, number of cycles up to 10000 5000 * - properties are given for products pressed from granules obtained according to the indicated options.

The data shown in table 1 indicate that the proposed installation allows to obtain metal powders (granules) of various sizes, including ultrafine with a particle size of less than 100 microns more homogeneous fractional composition, which increases the level of physico-mechanical properties of products pressed from them. The service life of products under a fixed load increases, as follows from the data in table 1, also up to two times.

Claims (1)

An apparatus for producing a metal powder, comprising a melting chamber with a heater, a mechanism chamber connected to it, a billet dispenser in the melting chamber, a vacuum system, a receiving chamber, a powder collecting container and axial movement of workpieces with a pusher and a workpiece rotation mechanism with drive rolls, characterized in that the workpiece rotation mechanism is equipped with a pressure roller and bearing bearings with gas cooling devices, electrically insulating bushings of erosive erosion of the rolling surfaces of the bearings, with sensors for controlling the temperature and level of vibrations, while the drive rolls and the pressure roller of the workpiece rotation mechanism are mounted on the bearing supports, the pusher is made with a nozzle device at the end facing the workpiece supply side, and the melting chamber and the mechanism chamber are connected between themselves bypass pipe with valve.

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