Reduced pressure laser welding of thick section structural steel

This study investigates the influence of joint edge surface edge roughness and pre-set air gap on the weld quality and penetration depth in partial vacuum atmospheric conditions laser beam welding. High-power autogenous disk laser keyhole welding of low alloyed steel SM400A was carried out with butt joint configuration with 16 kW laser power and 1 m/min welding speed in partial vacuum atmospheric conditions. Geometry, quality of the welds was investigated. The results indicate that a significant increase in penetration depth can be achieved with constant heat input without loss of weld quality.