2001 Volume 19 Issue 3 Pages 424-432
In this study, the effect of laser pulse shot number on the hardness of weld metal and strength of welds was investigated. In the repair welding for such micro part as the cutter, laser welding was carried out to investigate the effects of pulse shot number for the hardness and strength of micro welded zone by the methods of changing pulse shot number under the condition that pulse output energy is constant. The following results were obtained in this study.
In the case of laser welding under the condition that pulse output energy is 30 J/P and pulse shot number change from 10 to 60 pulse, the hardness of weld metal was increased with increasing pulse shot number. However, the hardness of weld metal is low against the hardness of base metal.
The structure of martensite in the weld metal was decreased with increasing the pulse shot number, and pulse shot number is more than 30 pulse, the martensite in the weld metal disappeared from the weld metal.
The strength of welds was increased with increasing the pulse shot number, but the rate of increasing at the strength of welded joint were moderated under the condition that pulse shot number is more than 30 pulse.