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Comparative study of laser surface hardening of 50CrMo4 steel using continuous-wave laser and pulsed lasers with ms, ns, ps and fs pulse duration.
- Source :
-
Surface & Coatings Technology . May2019, Vol. 366, p311-320. 10p. - Publication Year :
- 2019
-
Abstract
- 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. Graphical abstract Unlabelled Image Highlights • Millisecond laser of 9 times lower power is as effective as cw laser in surface hardening and produces hardness as high as 719 HV. • Nanosecond laser is less effective than cw laser in surface hardening. It produces shallow hardened depth (~80 μm) with hardness of about 642 HV. • Femtosecond and picosecond lasers result in no hardening of surface. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 02578972
- Volume :
- 366
- Database :
- Academic Search Index
- Journal :
- Surface & Coatings Technology
- Publication Type :
- Academic Journal
- Accession number :
- 135709584
- Full Text :
- https://doi.org/10.1016/j.surfcoat.2019.03.036