Surface transformation hardening of ductile cast iron by a 600w fiber laser
Abstract
Laser transformation surface hardening of the forming edges of large mold made of nodular cast iron has gained momentum in recent years. In this investigation a 600 w fiber laser was employed to harden GGG-60 cast iron. It is found that to achieve the optimum surface properties, the combination of laser power density and travel speed has to be set such that to dissolve the carbides but not that high to dissolve the graphite nodules. The response of a hardened track to a second thermal cycle by a neighboring laser track in terms of both tempering and re-hardening showed that by increasing the overlapping, a more uniform surface microstructure and hardness is obtained. In addition by employing differential scanning calorimetry (DSC) analysis the maximum "Hardening Ratio" by the fiber laser as the power source for GGG-60 cast iron was found to be 15.3 %.
- Publication:
-
Optik
- Pub Date:
- February 2020
- DOI:
- 10.1016/j.ijleo.2019.163758
- Bibcode:
- 2020Optik.20363758G
- Keywords:
-
- Fiber laser;
- Laser transformation hardenign;
- Hardenign ratio;
- Overlapping;
- Temparing