Suppression of porosity in beam weaving laser welding

Abstract

The present paper describes a beam weaving laser welding technique to suppress argon or nitrogen porosity, which may appear during laser welding of low carbon steel. Bead on plate welding was performed using a 3 kW CO₂ laser. The weaving frequency was varied within 0–30 Hz and the weaving amplitude within 0–2 mm during welding. The experimental results show that under 2.4 kW laser power and 1.0 m min^-1 welding speed, the nitrogen porosity decreases remarkably with increasing frequency, and it can be eliminated for a weaving frequency of 22 Hz with 0.5 mm weaving amplitude. Under 2.4 kW laser power and 1.5 m min^-1 welding speed, beam weaving laser welding can also effectively reduce argon porosity at a weaving frequency of 22 Hz and amplitude of 1.0–1.5 mm.