Розроблено вдосконалену схему процесу електродугової металізації. Вона дозволяє врахувати плавлення оболонки і прилеглого порошкового стержня за рахунок обмеженої дії розпилюючого струмення безпосередньо на «внутрішню» поверхню торців електродів. Цей ефект забезпечує можливість протікання металургійних процесів і отримання легованих частинок при розпиленні порошкових електродів Ключові слова: електродугова металізація, порошковий стрижень, легування, газове середовище, розпорошуючий струмінь Разработана усовершенствованная схема процесса электродуговой металлизации. Она позволяет учесть плавление оболочки и прилегающего порошкового стержня ввиду ограниченного действия распыляющей струи непосредственно на «внутреннюю» поверхность торцов электродов. Этот эффект обеспечивает возможность протекания металлургических процессов и получение легированных частиц при распылении порошковых электродов Ключевые слова: электродуговая металлизация, порошковый стержень, легирование, газовая среда, распыляющая струя

No abstract

The essence of the process of electric arc spraying, consists in melting the electrodes with an electric arc and continuous separation of the liquid metal formed at the ends of the electrodes, a stream of compressed air and dispersing it on the sprayed surfaceTo use the periodic removal of pulsating air flow of liquid metal from the ends of the electrodes, it is important to solve the problem of guaranteeing the exclusion of short circuits of electrodes in the complete absence of spray flow and constant continuous supply of electrodes to the combustion zone of the arc. short circuit and when the spray flow is turned on after a pause will ensure the separation and transportation of liquid metal from the ends of the electrodes on the sprayed surface.It is important to determine the optimal mass of liquid metal and the time of formation of a drop of liquid metal depending on the technological parameters of the sprayed electrodes and the energy level of the arc that melts the electrodes.Studies of the determining factors of this process, namely the parameters of the electric arc mode, diameter, material and feed rate of the electrodes are presented.

No abstract

The paper aims to investigate the airflow dynamics of electric-arc spraying (EAS) with airflow pulsation. The study is focused on the dynamic structure of the airflow with an obstacle in the form of crossed electrodes at the steady and the pulsating air supply (with a frequency up to 120 Hz). The work was fulfilled using a computer simulation, the airflow “shadow” photo visualization, and the microstructure characterization of the coatings formed. It was found that when air flows along the crossed electrodes with a gap of 2 mm, a depression zone appears in the flow with a pressure drop from 0.56 MPa to 0.01 MPa. The air pulsation resulted in a change in a flow’s dynamic structure towards an increase in the length of the depression zone, which covers most of the arc, affecting the liquid metal oxidation. It is established that the frequency of a droplet formation should match the frequency of the airflow pulsation to minimize the metal oxidation. With the air pulsating at about 65 Hz, the oxide volume fraction in the aluminum coating was reduced by 3.6 times compared to the steady airflow. EAS with airflow pulsation has the potential for technological cost reduction.