Study On The Process Of Arc Ignition By Spectroscopic Diagnosis

TIG welding has been widely applied in various industries for its better welding quality. Arc ignition is one of the important steps, so to understand arc ignition and its fundamental features deeply is meaningful for procedure control and quality improvement.This paper used spectroscopic method to diagnose TIG arc ignition. With advanced spectrometer, the emission spectra of arc ignition with low-carbon steel as positive pole, was observed. The switching process of element which supply electron was analyzed.It is difficult to satisfy global or local thermal balance at the beginning of arc ignition, so this paper applied Boltzmann figure method to get excited temperature and Stark broadening method to get electron density. Boltzmann figure method allows spectra off global thermal balance, and Stark broadening method has no relationship with local thermal balance, so these methods provide theoretical support for the study of arc ignition.Many jobs were done to support the study of arc ignition mechanics, such as designing trigger circuit, taking spectra signal and calculating excited temperature and electron density.This paper summarized the transition features of excited temperature and electronic density. According to arc ignition steps and the voltage and current feature, the reason for their transition was analyzed and the physical meaning of arc ignition was discussed. Arc ignition and arc reignition were compared, and their identities and differences were given.