Effects of Oscillation Width on Arc Characteristics and Droplet Transfer in Vertical Oscillation Arc Narrow-Gap P-GMAW of X80 Steel

In fields, such as oil and gas pipelines nuclear power, narrow-gap welding has often been used for the connection of thick medium-thick plates. During process, a lack fusion was prone to occur due groove size limitations, seriously affecting service safety large structures. The vertical oscillation arc pulsed metal (P-GMAW) method adopted in this study. influence width on morphology, droplet transfer behavior weld formation during studied. Oscillation widths from 0 4 mm were grooves with bottom 6 mm. results show that, non-oscillation welding, always presented bell cover shape, form one per pulse, while sidewall penetration relatively small, making it fusion. With an increase width, gradually shifted sidewall. mode mixed small droplets, continued increase, which conducive However, when wider than 3 mm, led phenomenon climbing sidewall, porosity, undercutting other defects. major impact stability process welding.