For solving the problems of nitrogen escape and splash in the droplet transfer process of high-nitrogen steel additive manufacturing, the experiment of droplet transfer in an ultrasonic frequency pulsed gas metal arc (UFP-GMA) additive manufacturing is carried out, and the influences of different ultrasonic frequency pulsed current superposition modes and pulse current frequencies on the stability of high-nitrogen steel droplet transfer are studied, The process parameters that can realize the stable droplet transfer of high-nitrogen steel additives were obtained. The experimental results show that the of one-pulse-one-droplet transfer can be realized under the pulsed gas metal arc (P-GMA) process conditions, but the transition stability is poor and the splash is obvious. Superimposing the ultrasonic frequency pulse current at the base current stage of P-GMA or both at the base and peak current stages is not conducive to the droplet transfer, and the problems such as short circuit and droplet explosion are prone to occur. When the low-frequency (20 kHz) pulse current is applied during the peak stage, its effect on droplet transfer is minimal. However, the medium-frequency (40 -60 kHz) pulse currents can be superimposed to inhibit the generation of large particle splash, leading to improved stability in droplet transfer, but many small splashes will be formed during the transition when the frequency exceeds 60 kHz. © 2024 China Ordnance Industry Corporation. All rights reserved.
