CN113059169A - Device for producing high-temperature metal powder by adopting turntable centrifugal atomization method - Google Patents

Abstract

The invention provides a device for producing high-temperature metal powder by adopting a turntable centrifugal atomization method, which comprises the following steps: a heating vessel containing metal and melting the metal into a metal stream by heating; the atomizing chamber is used for receiving the metal liquid flow generated by the heating container and generating metal powder by a centrifugal atomization method, and comprises an atomizing cavity connected with the heating container, a rotary disc positioned in the atomizing cavity, a driving device for driving the rotary disc to rotate, and a conical discharge pipe arranged at the bottom of the atomizing cavity; and the cooling system is used for cooling the atomizing cavity, and comprises a cooling interlayer which is arranged on the side wall of the atomizing cavity and used for circulating a flowing cooling medium, and a cooling nozzle which is used for spraying inert gas into the atomizing cavity. In the whole centrifugal atomization process, the atomization cavity is cooled circularly by cooling water, internal equipment is subjected to thermal protection and inert atmosphere protection by high-pressure inert gas sprayed by each nozzle, each equipment can stably work at the temperature of more than 500 ℃, and the centrifugal atomization of high-melting-point metal is realized.

Description

Device for producing high-temperature metal powder by adopting turntable centrifugal atomization method

Technical Field

The invention relates to the field of metal atomization, in particular to a device for producing high-temperature metal powder higher than 500 ℃ by adopting a turntable centrifugal atomization method.

Background

At present, the atomization techniques applied to high-temperature metal powder mainly include gas atomization (AA method), vacuum induction gas atomization (VIGA method), crucible-free electrode induction melting gas atomization (EIGA method), plasma torch method (PA method), plasma rotation atomization (PREP method), and rotary disk centrifugal atomization.

In the case of the typical VIGA and PREP processes, the EIGA process melts a slowly rotating electrode material by a high frequency induction coil and forms a fine liquid stream (the liquid stream does not need to contact a water-cooled crucible and a draft tube) by controlling the melting parameters, and as the alloy liquid stream flows through an atomizing nozzle, the liquid stream is broken up and solidified by a high-speed pulse gas stream generated by the atomizing nozzle to form fine powder particles. The EIGA method powder has the biggest advantages of no refractory material inclusion and low energy consumption, and has the defects that the granularity of metal powder prepared by the prior domestic technology is relatively large, and the segregation of an electrode can cause the uneven components of an alloy powder material. The powder prepared by the PREP method has the advantages of clean surface, high sphericity, few associated particles, no hollow/satellite powder, good fluidity, high purity, low oxygen content, narrow particle size distribution and the like. However, the PREP process is limited by related technical bottlenecks such as sealing and vibration caused by a large increase in the speed of the electrode rod, and it is still difficult to prepare fine particle size powder at low cost by using this method.

At present, a rotating disc centrifugal atomization method is commonly used, wherein metal liquid flows to the center of a rotating disc surface rotating at a high speed, and fine liquid drops are thrown out from the edge of the rotating disc and are solidified into powder particles under the action of centrifugal force. The rotary disc atomization has the advantages of low cost, high particle size concentration ratio and the like, but the traditional rotary disc centrifugal atomization equipment is limited by the temperature resistance of the rotary disc and other accessory equipment, and cannot carry out centrifugal atomization powder preparation of high-temperature metal (metal with a melting point above 500 ℃).

Disclosure of Invention

The invention aims to provide a device for producing high-temperature metal powder higher than 500 ℃ by adopting a turntable centrifugal atomization method.

The invention provides a device for producing high-temperature metal powder by adopting a rotary disc centrifugal atomization method, which comprises the following steps:

a heating vessel containing metal and melting the metal into a metal stream by heating;

the atomizing chamber is used for receiving the metal liquid flow generated by the heating container and generating metal powder by a centrifugal atomizing method, and comprises a cylindrical atomizing cavity connected with the bottom of the heating container, a turntable positioned in the atomizing cavity and used for receiving the metal liquid flow through the upper surface, a driving device for driving the turntable to rotate, and a conical discharge pipe arranged at the bottom of the atomizing cavity and used for collecting and discharging the metal powder;

and the cooling system is used for cooling the atomizing cavity, and comprises a cooling interlayer which is arranged on the side wall of the atomizing cavity and used for circulating a flowing cooling medium, and a cooling nozzle which is used for spraying inert gas into the atomizing cavity.

The metal is melted into the molten metal by the heating furnace, the turntable is driven by the high-speed motor to rotate at a high speed, the molten metal flowing to the upper surface of the turntable is thrown away at a high speed by the centrifugal force to form liquid drops, the liquid drops are condensed and solidified into metal powder, the atomization cavity is circularly cooled by cooling water in the whole centrifugal atomization process, high-pressure inert gas sprayed by each nozzle is used for carrying out thermal protection and inert atmosphere protection on internal equipment, each equipment can stably work at the temperature of more than 500 ℃, and the centrifugal atomization of the high-melting-point metal is realized.

Drawings

FIG. 1 is a schematic diagram of the structure of an apparatus according to an embodiment of the present invention.

Detailed Description

The detailed structure and implementation process of the present solution are described in detail below with reference to specific embodiments and the accompanying drawings.

In one embodiment of the present invention, as shown in fig. 1, an apparatus for producing high-temperature metal powder by using a rotary disk centrifugal atomization method is disclosed, which comprises a heating container, an atomization chamber and a cooling system.

The heating container is used for containingmetal 1 and melting themetal 1 into a metalliquid flow 4 by heating; the specific heating container can adopt any structure which can bear the added high temperature and can melt the metal, such as a container made of stainless steel, graphite or ceramic and other materials; this embodiment choosescrucible 3 of graphite preparation for use, and the outer circumference ofcrucible 3 is around setting upheating furnace 2 that carries out the heating to the metal incrucible 3, andheating furnace 2's heating method can be resistance-type or inductance type, installs the temperature controller of automatic control heating temperature simultaneously, and the temperature controller can self-heating to predetermined temperature and accuse temperature keep, reduces operating personnel's intensity of labour.

Theheating furnace 2 can be arranged only around the outer circumference of thecrucible 3, and the upper end and the lower end of thecrucible 3 are exposed, so that metal can be conveniently added into thecrucible 3 and molten metal in thecrucible 3 can be conveniently discharged; thecrucible 3 is provided with a lid which can be opened and closed at the top so as to put metal in and close thecrucible 3 during the heating process, and the bottom of thecrucible 3 is provided with avalve 5 for controlling the molten metal to pass through, and the bottom of thecrucible 3 can be arranged into a reverse cone shape so as to facilitate the collection of themolten metal 4, and thevalve 5 is arranged at a cone-shaped outlet. In order to prevent heat loss, the outer wall of theheating furnace 2 can be wrapped with a high-temperature-resistant insulating layer, such as a asbestos wool layer.

The metal to be melted used in the present embodiment may be a metal having a melting point of 500 ℃ or higher, and thespecific metal 1 may be an aluminum ingot, a copper ingot, a stainless steel ingot, a high-temperature alloy ingot, or the like which has been purified, wherein the content of impurities in themetal 1 is required to be 1% or less, the oxygen content is required to be less than 1, and the high-purity metal 1 satisfying this condition can be directly melted into themolten metal 4 for pulverization by atomization without smelting.

The atomizing chamber is used for receivingmolten metal 4 generated by a heating container and generating metal powder by a centrifugal atomization method, and specifically comprises a cylindrical atomizingcavity 6 connected with the bottom of the heating container, arotary disc 12 positioned in the atomizingcavity 6 and used for receiving themolten metal 17 through the upper surface, adriving device 14 for driving therotary disc 12 to rotate, and a conical discharge pipe arranged at the bottom of the atomizingcavity 6 and used for collecting and discharging the metal powder; theheating furnace 2 and thecrucible 3 can be respectively arranged at the upper part of the atomizingcavity 6, and the bottom outlet of thecrucible 3 is communicated with the atomizingcavity 6, so thatmolten metal 4 after being heated and melted can directly flow into the atomizingcavity 6 from the bottom outlet to form amolten metal flow 17 which directly falls on theturntable 12.

Theturntable 12 is driven by thedriving device 14 to rotate at a predetermined rotation speed during operation, and the rotation speed of theturntable 12 in this embodiment needs to be more than 1 ten thousand rpm. The axis of the installed rotary table 12 is coincident with the axis of the atomizingcavity 6, the distance between the inner wall of the atomizingcavity 6 and the outer circumference of the rotary table 12 is larger than the track length of the metalliquid flow 17 solidified into metal powder after centrifugal atomization, and when the distance is smaller than the track length, liquid drops thrown out by centrifugation are adhered to the inner wall surface of the atomizingcavity 6, so that the metal powder cannot be generated.

The specific rotary table 12 comprises a thin cylindrical disc and adisc shaft 13, the size of the disc is 30-200 mm, the thickness of the disc is 0.5-10 mm, the disc can be made of metal or nonmetal and other hard materials capable of bearing the temperature ofmolten metal flow 17, the disc is in a horizontal state after being installed, and the circle center of the upper surface is in contact with themetal flow 17; thedisc shaft 13 is provided on the lower surface of the disc for connection with other members (e.g., a coupling), and thedisc shaft 13 may be integrally formed with the disc or may be separately formed and then welded or bonded to the disc.

Thedriving device 14 can use a high-speed motor as a power source (in the following description, the driving device is replaced by a high-speed motor) to drive theturntable 12 to rotate at a high speed, and the rotating speed of the high-speed motor 14 needs to reach more than 1 ten thousand rpm. In order to adjust the rotating speed, the high-speed motor 14 is driven by a frequency converter, and water is introduced into the high-speed motor 14 for cooling and ensuring good lubrication. In order to perform sufficient thermal protection, a high-temperature-resistant heat insulation layer can be wrapped on the periphery of the high-speed motor 14.

The high-speed motor 14 can connect the driving shaft with thedisk shaft 13 through a coupling, so as to transmit the torque and the rotating speed of the high-speed motor 14 and drive the rotatingdisk 12 to rotate at a high speed. The high-speed motor 14 is located below theturntable 12, and can prevent the metalliquid flow 17 or the centrifuged metal powder from falling on the high-speed motor 14.

The cooling system is used for cooling the inside of the atomizingcavity 6 and comprises acooling interlayer 10 which is arranged on the side wall of the atomizingcavity 6 and used for circulating a flowing cooling medium, and a cooling nozzle which is used for spraying inert gas into the atomizingcavity 6. The side wall of the atomizingcavity 6 adopts a double-layer structure to form acooling interlayer 10, and the heat absorbed by the inner wall of the atomizingcavity 6 is taken away by a cooling medium which circulates and flows inside, wherein the specific cooling medium can be water, oil or air and other media which can flow. The cooling medium used in this embodiment is water, and the water in thecooling jacket 10 performs heat exchange with a cooling tower or a reservoir separately provided outside.

In order to improve the strength of thecooling interlayer 10, a plurality of reinforcing plates (not shown in the figure) are arranged in the cooling interlayer, the plate adding plates divide the interior of thecooling interlayer 10 into a plurality of mutually communicated cooling channels, the cooling channels in thecooling interlayer 10 can be a plurality of vertically distributed mutually communicated channels, cooling water enters the cooling channels from the upper part of thecooling interlayer 10, heated water after heat absorption is discharged from the lower outlet of thecooling interlayer 10, then is replaced with an external cooling device, and enters the cooling interlayer from the upper part of the cooling interlayer to form a circulation. The cooling channels can also be a plurality of channels distributed helically around theatomising chamber 6, in a manner consistent with the vertical configuration described above and will not be repeated here.

The cooling nozzles generally includedroplet nozzles 11 symmetrically arranged around the rotatingdisk 12 for cooling centrifugally separateddroplets 19, adisk shaft nozzle 15 for cooling thedisk shaft 13, and amotor nozzle 16 for cooling thehigh speed motor 14. Theliquid drop nozzle 11 is arranged at the upper edge inside the atomizingchamber 6, and 2 or more liquid drop nozzles can be arranged according to the flow and pressure requirements. Theliquid drop nozzle 11 can blow high-pressure low-temperature inert gas (such as nitrogen or argon), so thatliquid drops 19 generated after centrifugal atomization are rapidly cooled and solidified into powder, and can form strong enough wind power to form gas-powder mixedflow 20 with metal powder, thereby facilitating the transportation of the metal powder. Moreover, the inert gas sprayed from theliquid drop nozzle 11 can form an inert gas environment inside the atomizingchamber 6 to prevent oxidation of the high temperature metal powder.

Thedisk shaft nozzle 15 can simultaneously cool thedisk shaft 13 and the coupling of the rotatingdisk 12 by ejecting high-pressure low-temperature inert gas (nitrogen or argon) which is the same as theliquid drop nozzle 11, and prevent high-temperature heat on the rotatingdisk 12 from being transmitted to the coupling and even the high-speed motor 14 through thedisk shaft 13.

Themotor nozzle 16 cools the high-speed motor 14 by spraying the same high-pressure low-temperature inert gas (nitrogen or argon) as theliquid drop nozzle 11, and prevents the high-speed motor 14 from being burned out by the high temperature inside the atomizingchamber 6.

The working process of the embodiment is as follows:

adding ametal 1 block or ingot into acrucible 3, opening aheating furnace 2 to heat thecrucible 3, and melting themetal 1 block or ingot intomolten metal 4 in thecrucible 3 when the temperature reaches a set value;

starting cooling water in thecooling interlayer 10 for circulation, opening the liquid droppingnozzle 11, thedisc shaft nozzle 15 and themotor nozzle 16 at the same time, and starting the high-speed motor 14 to drive theturntable 12 to rotate at a preset rotating speed;

and opening avalve 5 at the bottom of thecrucible 3, vertically discharging themolten metal 4, forming a metalliquid flow 17, and allowing the metalliquid flow 17 to enter an atomizingcavity 6, wherein the shape of the metalliquid flow 17 is a stable liquid column with the diameter of 1-3 mm, and the metalliquid flow 17 falls to the center of the upper surface of theturntable 12. Then the metalliquid flow 17 is diffused outward from the center of the upper surface of the rotatingdisc 12 to form a thinliquid film 18 under the multiple actions of gravity, fluid pressure and rotating disc centrifugal force and flows to the outer edge of the rotatingdisc 12, theliquid film 18 flowing to the edge of the rotatingdisc 12 is thrown away at high speed under the combined action of fluid inertia force and rotating disc centrifugal force and is contracted intoliquid drops 19 under the action of surface tension, and the high-temperature liquid drops 19 exchange heat with low-temperature inert gas sprayed by theliquid drop nozzle 11 in the flying process and are finally cooled and solidified into metal powder.

The metal powder is driven by the inert gas in the atomizingcavity 6 to form a gas-powder mixedflow 20, and the gas-powder mixed flow is spirally collected to a conical discharge pipe downwards and then discharged to next equipment (such as a powder collecting tank or a powder particle size classifier), so that the whole rotary disc centrifugal atomizing process of the high-temperature metal is completed.

In the embodiment, metal is melted into molten metal through the heating furnace, the high-speed motor drives the rotary table to rotate at a high speed, the molten metal flowing to the upper surface of the rotary table is thrown away at a high speed by the action of centrifugal force to form liquid drops, the liquid drops are solidified into metal powder when meeting condensation, the atomization cavity is circularly cooled through cooling water in the whole centrifugal atomization process, high-pressure inert gas sprayed by each nozzle is utilized to carry out thermal protection and inert atmosphere protection on internal equipment, the equipment can stably work at more than 500 ℃, and the centrifugal atomization of high-melting-point metal is realized.

In the present embodiment, in order to ensure good fluidity of themolten metal 4 and prevent the molten metal from being cooled and solidified during the flowing process, the temperature of themolten metal 4 needs to be higher than the melting point of the metal material by about 100 ℃.

Atomizing chamber accessible bottom welded supportingleg 7 supports subaerial, and supportingleg 7 accessible rag bolt and ground are firmly installed.

In order to facilitate the discharge of the metal powder, anelbow 8 bent to one side can be connected at the outlet of the conical discharge pipe, and theelbow 8 can adopt a 90-degree elbow and can also be designed into a required angle according to the position of downstream equipment. In addition, a pipeline interface 9 convenient for downstream equipment to be connected can be connected to theelbow 8, and the pipeline interface 9 can be designed into a flange connection mode and can also be directly welded according to requirements. The downstream equipment refers to equipment such as a powder collecting tank or a powder particle size classifier.

Thus, it should be appreciated by those skilled in the art that while a number of exemplary embodiments of the invention have been illustrated and described in detail herein, many other variations or modifications consistent with the principles of the invention may be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be understood and interpreted to cover all such other variations or modifications.

Claims (10)

Translated fromChinese

1.一种采用转盘离心雾化法生产高温金属粉末的装置，其特征在于，包括：1. a device that adopts rotary disc centrifugal atomization method to produce high temperature metal powder, is characterized in that, comprises:加热容器，容纳金属并通过加热使金属熔化成金属液流；Heating the vessel, containing the metal and melting the metal into a liquid metal stream by heating;雾化室，接收加热容器生成的金属液流并通过离心雾化法生成金属粉末，包括与加热容器底部连接的圆桶形雾化腔，位于雾化腔内通过上表面承接金属液流的转盘，驱动转盘转动的驱动装置，设置在雾化腔底部用于汇集金属粉末并排出的锥形排放管；The atomization chamber receives the metal liquid flow generated by the heating container and generates metal powder by centrifugal atomization, including a barrel-shaped atomization cavity connected to the bottom of the heating container, and is located in the atomization cavity through the upper surface. , a drive device that drives the turntable to rotate, and a conical discharge pipe arranged at the bottom of the atomization chamber for collecting and discharging metal powder;冷却系统，用于对雾化腔内进行降温，包括设置在雾化腔侧壁处循环流动冷却介质的冷却夹层，和对雾化室内部喷射惰性气体的冷却喷嘴。The cooling system is used for cooling down the atomization chamber, including a cooling interlayer which is arranged at the side wall of the atomization chamber to circulate a cooling medium, and a cooling nozzle for spraying inert gas inside the atomization chamber.2.根据权利要求1所述的装置，其特征在于，2. The device according to claim 1, characterized in that,所述加热容器包括容纳金属的坩埚，和围绕坩埚设置以对坩埚内金属进行加热的加热炉；所述坩埚的底部设置有控制金属液流通过的阀门，所述加热炉的外壁包裹有耐高温保温层。The heating vessel includes a crucible for accommodating metal, and a heating furnace arranged around the crucible to heat the metal in the crucible; the bottom of the crucible is provided with a valve for controlling the flow of molten metal, and the outer wall of the heating furnace is wrapped with high temperature resistant Insulation.3.根据权利要求2所述的装置，其特征在于，3. The device of claim 2, wherein所述加热炉的加热方式为电阻式或电感式，且安装有自动控制加热温度的温控器。The heating method of the heating furnace is a resistance type or an inductance type, and a temperature controller for automatically controlling the heating temperature is installed.4.根据权利要求2所述的装置，其特征在于，4. The device of claim 2, wherein所述加热容器中容纳的金属熔点至少在500℃以上，且金属中的杂质含量在1％以下，氧含量低于1。The melting point of the metal contained in the heating vessel is at least above 500° C., the impurity content in the metal is below 1%, and the oxygen content is below 1.5.根据权利要求4所述的装置，其特征在于，5. The device of claim 4, wherein所述加热容器中生成的金属液流的温度比金属的熔点高80～120℃。The temperature of the liquid metal stream generated in the heating vessel is 80-120° C. higher than the melting point of the metal.6.根据权利要求1所述的装置，其特征在于，6. The device of claim 1, wherein所述转盘的轴线与所述雾化腔的轴线重合，且所述雾化腔的内壁至所述转盘外圆周之间的距离大于金属液流雾化后凝固成金属粉末的轨迹长度。The axis of the turntable coincides with the axis of the atomization cavity, and the distance from the inner wall of the atomization cavity to the outer circumference of the turntable is greater than the track length of the molten metal flow after atomization and solidification into metal powder.7.根据权利要求1所述的装置，其特征在于，7. The device of claim 1, wherein所述转盘的下表面圆心处固定有凸出的盘轴，所述驱动装置为安装在所述转盘下方的电机，电机通过驱动轴或联轴器与盘轴连接。A protruding disk shaft is fixed at the center of the lower surface of the turntable, the driving device is a motor installed under the turntable, and the motor is connected to the disk shaft through a drive shaft or a coupling.8.根据权利要求7所述的装置，其特征在于，8. The device of claim 7, wherein所述冷却喷嘴包括对称布置在所述转盘四周对离心脱离的液滴进行冷却的液滴喷嘴，和对所述盘轴进行冷却的盘轴喷嘴，以及对所述电机进行冷却的电机喷嘴。The cooling nozzles include droplet nozzles symmetrically arranged around the turntable to cool centrifugally separated droplets, disc shaft nozzles to cool the disc shaft, and motor nozzles to cool the motor.9.根据权利要求1所述的装置，其特征在于，9. The device of claim 1, wherein:所述冷却夹层中使用的冷却介质为水，水与外部的冷却塔或蓄水池进行循环换热。The cooling medium used in the cooling interlayer is water, and the water performs circulating heat exchange with an external cooling tower or a water reservoir.10.根据权利要求1所述的装置，其特征在于，10. The device of claim 1, wherein所述冷却夹层内设置有多道加强板，加板板将所述冷却夹层内部间隔为多道相互连通的冷却槽道。The cooling interlayer is provided with a plurality of reinforcing plates, and the plate-adding plate separates the cooling interlayer into a plurality of cooling channels which are communicated with each other.

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