Influence of laser energy on weld quality during blue laser spot-welding of electrical steel laminations

Blue laser spot welding electrical steel can improve material absorption, stabilise the molten pool and reduce heat input. The influence of process parameters on the welding quality of blue laser spot welding electrical steel is investigated. With the increase of laser power, a ‘single hump’ molten pool was generated. At the power of 1000 W, the melting mode changed, and the plume appeared above the molten pool. The maximum penetration depth was 0.75 mm (laser power 1000 W, pulse time 1 s). Higher laser energy led to a continuous increase in the proportion of columnar grains, exceeding 45% at 1000 J. Finally, higher laser power and pulse time enhanced the connection and bonded area of laminations.