Dynamic behavior of plasma and molten pool of pure titanium during hyperbaric laser welding

Abstract

In this study, the influence of increasing the ambient pressure on the penetration of pure titanium during fiber spot laser welding was studied. Theresultsindicatedthat the penetration of pure titanium decreased significantly with an increase in ambient pressure. Under the experimental conditions in this study, when the ambient pressure increased from 0.1 to 1.8 MPa, the penetration changed from 3.6 to 1.2 mm, decreasing by approximately 67%. A high-speed camera and spectrometer were used to analyze the mechanism of the sharp decline in penetration. First, the rate of plasma expansion and the cross-section area of pure titanium under different ambient pressures were observed using a high-speed camera. Subsequently, a spectrometer was used to detect the plasma intensity of pure titanium during laser welding under different ambient pressures. Finally, the influence of changes in environmental pressure on the dynamic behavior of a pure titanium molten pool was studied by using high-speed photography and “glass-metal composite samples”. The results of this research could help in enriching the theory regarding laser processing under hyperbaric conditions and develop laser manufacturing technology for offshore engineering structures.