Metal spattering in laser scanning welding of T2 copper and welding quality

•Laser linear welding and laser scanning welding of “O” , “8” and “∞” shape trajectory were studied on T2 copper.•The metal spattering during welding was studied through high-speed photography and image processing technology.•Laser scanning welding exhibits better stability of welding process and better property compared with the conventional laser linear welding.•Under the “O” shape scanning trajectory, the joints have the best inhibition effect on metal spattering during welding.•The highest tensile strength, lowest porosity and highest conductivitywas obtained with the “O” shape scanning trajectory.