Comparative study of laser surface hardening of 50CrMo4 steel using continuous-wave laser and pulsed lasers with ms, ns, ps and fs pulse duration

Comparative study of laser surface hardening of 50CrMo4 steel using continuous-wave laser and pulsed lasers with ms, ns, ps and fs pulse duration
Title:
Comparative study of laser surface hardening of 50CrMo4 steel using continuous-wave laser and pulsed lasers with ms, ns, ps and fs pulse duration
Other Titles:
Surface & Coatings Technology
Publication Date:
19 March 2019
Citation:
Maharjan, N., Zhou, W., Zhou, Y., Guan, Y. and Wu, N., 2019. Comparative study of laser surface hardening of 50CrMo4 steel using continuous-wave laser and pulsed lasers with ms, ns, ps and fs pulse duration. Surface and Coatings Technology, 366, pp.311-320.
Abstract:
Laser surface hardening, used to achieve hardened surface without affecting bulk properties of steels, generally employs continuous-wave laser to do the job. The purpose of this paper is to systematically investigate the use of different pulsed lasers for surface hardening of 50CrMo4 steel. A continuous-wave laser and various pulsed lasers with pulse duration ranging from fs to ms were used for the experiment. It was found that millisecond laser utilizing about 9 times lower power is as effective as continuous-wave laser for surface hardening. It produced an average surface hardness of ~719 HV (2.7 times higher than base material hardness) and ~200 μm hardened depth, which is comparable with continuous-wave laser hardening. Similarly, nanosecond laser could induce both surface hardening effect and material removal depending on the parameters used. However, a shallow hardened depth (of mere ~80 μm) was achieved compared to continuous-wave laser. Furthermore, femtosecond and picosecond lasers did not produce any observable surface hardening effect; instead they resulted in direct surface ablation.
License type:
http://creativecommons.org/licenses/by-nc-nd/4.0/
Funding Info:
A*STAR SINGA Scholarship Collaborative Research Project RCA-15/287
Description:
ISSN:
0257-8972
1879-3347
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