SU894955A1 - Method for producing sintered porous articles - Google Patents

Abstract

METHOD OF MANUFACTURING SINTERED POROUS PRODUCTS, including pressing a billet from a powder and hardening it by passing a pulsed high-frequency electric current, characterized in that, in order to simplify and increase the safety of the method, the hardening process on the billet is applied by a closed current by turning off the latter in the inductor by means of a conductor explosion .

Description

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SP 189 The invention relates to the field of powder metallurgy, in particular, to methods for producing sintered porous products, and can be used to make consumable electrodes used in metallurgists of titanium and its alloys. A known method of manufacturing porous consumable electrodes, comprising pressing the mixture through a conical mold. The disadvantage of this method is that the resulting electrodes have a low mechanical strength, which causes breakage of the electrodes during transportation and their breakdown in the smelting process. There is also known a method for manufacturing sintered portions of products, in particular electrodes, including granulation of the initial powder, molding by vibro-processing and sintering. The method is used to manufacture electrodes based on metal diboride, which limits its use. In addition, the method involves sintering in furnaces, which lengthens and complicates the process. There is also known a method of making sintered consumable electrodes from refractory compounds, including annealing the powder of a refractory compound, grinding the cake, sieving fractions, molding and sintering at a temperature of 1800-2100 C. A disadvantage of this process is that it requires sintering in furnaces and long heating to high temperature. The closest to the proposed technical essence and the achieved effect is the method of manufacture. no sintered porous products, including pressing of the blank of powder, and its strengthening by passing a pulsed high-frequency electric current. The disadvantage of this method is that complex equipment, including high-voltage high-voltage capacitor battery and high-voltage charging device, is required to pass through the workpiece during its hardening and high-voltage charging. The use of high voltage equipment in metallurgical shops creates difficulties in ensuring safety of work. The purpose of the invention is to simplify and increase the security of the method. This is achieved by the fact that the method of pressing the billet from the powder and its hardening by passing a high-frequency pulse current in the hardening process is applied to the billet with a closed current by turning off the conductor in the inductor by means of an explosive conductor. the inductor, create in the inductor the current discharged capacitor battery. The time of current flowing through the inductor is determined from the relation T 3 ' -, the circuit constant, where L, where L is the inductance of the circuit; R is the active resistance of the circuit. During this time, the current in the inductor reaches the value Ipa at which the current is switched off by an electrical explosion of the copper conductor. The dimensions of the conductor are calculated based on the values of the Airborne Forces and C according to the known method. At the moment when the current is turned off, a high voltage pulse is created on the inductor by hardening the workpiece. After turning off the current, the workpiece is removed from the inductor. When implementing the method, an inductor is used, which is a single-turn or multi-turn solenoid. The workpiece is placed inside the solenoid. With an abrupt shutdown of the current H of the inductor, bypassing any closed loop encompassing the magnetic flux, a voltage proportional to the change in the magnetic flux is induced in the workpiece. U This voltage causes a closed current. Thus, an inductive energy storage device is used instead of a high-voltage capacitor battery, and a high voltage appears only as a short pulse. Since the current is closed inside the workpiece, no contacts are required for the supply and removal of current. Example. A solenoid with an internal

with a diameter of 44 mm, a length of 250 mm, a number of turns 63, with a diameter of a turn mm and an inductance of 44 μg.

To create a current in the inductor, a battery of capacitors with a capacity of 400 microfarads and a voltage of 3 kV was used, connected to the inductor, or through an ignitron equipped with an arson system.

From the mixture, containing 10% of the ligature A1-V and 90% of the titanium sponge, the billet was pressed through a conical mold. Received the workpiece with a diameter of 40 mm and a length of 200 mm. The billet was placed in an inductor and secured. Then a current was created in the inductor. B. For 10 seconds, the current in the inductor reached a value of 10 kA. After reaching this value, the shutdown was performed.

current by copping the copper conductor. A high voltage impulse arose on the inductor, which was used to strengthen the workpiece.

Billet hardened by known and proposed methods, were subjected to testing on a tensile machine.

As a result of the implementation of the proposed method, the tensile strength of the obtained products increased 1.5-3 times, and the electrical resistance decreased 2.5 times.

A high voltage pulse arises in the inductor for a short time,

only at the moment of switching off the current in the inductor circuit, which increases the safety of the process of manufacturing products from powder.

Claims (1)

METHOD FOR PRODUCING SINTERED POROUS PRODUCTS, including pressing a workpiece from a powder and hardening it by passing a high-frequency pulsed electric current, characterized in that, in order to simplify and improve the safety of the method, the workpiece is subjected to a closed current in the process of hardening by shutting off the latter in an inductor by an explosion conductor. 4 * CO SI JV manufacturing of electrodes, including through a cone - 10 1 894955