Abstract: Objective: To investigate the effect of different laser output voltages on the mechanical properties and the fatigue life of Co-Cr laser-welded joints. Methods: Dumbbell rods made of Co-Cr alloy were laser-welded in the output voltage of 220V, 250V and 280V, respectively (n=10). The non-weld group was chosen as control group. All groups were subjected to three-point bending test on the material testing machine, the maximum compressive stress values and fatigue life of specimen were record automatically. The fracture of specimen were subjected to Microscopic phase analysis. Results: The maximum compressive stress values of laser-welded groups were smaller than the non-weld group. The smallest values was found in the 220V group, and no statistically significant difference was found between 250V group and 280V group. The fatigue life of laser-welded groups increased along with the raises of output voltage, differences were statistically significant. The fatigue life of laser-welded groups were far shorter than non-weld group. Conclusion: The fatigue life of laser-welded joints increases along with the raises of output voltages within limits.

Key words: Laser-welding , Output voltage, Cobalt-chromium alloy, Fatigue life