The mechanical properties of H13 die steel repaired by a biomimetic laser technique

•The laser parameters were analyzed to obtain the weld without defects.•The microstructure and SEM fractographs of biomimetic samples were analyzed.•The propagation patterns of the cracks were analyzed.•The thermal fatigue resistance of weld samples was improved.•The strength of weld was improved by laser biomimetic treatment.

The H13 steel specimens with cracks were repaired by pulsed laser welding with filler wire and the laser parameters were analyzed to obtain the weld without defects. Strengthening units with different spacing were fabricated to improve the tensile strength and thermal fatigue resistance of the weld by laser technique on the surfaces of specimens, that is, PS-1, PS-2 and PS-3 for tensile specimens and PS for thermal fatigue specimen. The results indicated that the units have a beneficial effect on improving the tensile strength and thermal fatigue resistance of welded components of H13 steel. The improvement can be attributed to the microstructure characteristics within the units and the spacing of adjacent units is a key factor which affects the strength of weld by biomimetic treatment.