Laser Welded Assembly With HAZ Reinforcement for Stronger Joints

The patent applies parameter changes by modifying the laser welding parameters to create an underfilled weld with specific geometric characteristics. By controlling the laser power, welding speed, and focal position, the process creates a weld with a concave profile that positions the HAZ away from the stress concentration zone, thereby maintaining weld precision while mitigating strength loss from HAZ softening.

The patent implements local quality by creating a non-uniform weld geometry with an underfilled profile. The weld cross-section is deliberately made non-homogeneous, with a concave shape that concentrates material in specific regions. This local variation in weld geometry strategically positions the HAZ away from the notch root area, providing different functional properties in different zones of the weld.

The patent utilizes parameter changes by optimizing laser welding parameters to achieve an underfilled weld profile. By adjusting laser power, welding speed, and other process parameters, the method creates a specific weld geometry where the HAZ is positioned away from the stress concentration zone, thereby maintaining high energy density benefits while improving energy absorption capability.

The patent applies the blessing in disguise principle by converting the harmful effect of HAZ softening into a beneficial outcome. Instead of avoiding HAZ formation entirely, the method deliberately creates an underfilled weld that positions the HAZ in a location away from the notch root. This transforms the HAZ from a weakness into a feature that does not compromise joint reliability, thereby converting the harmful thermal effect into a beneficial geometric configuration.