The laser surface transformation hardening (LSTH) of AISI 4130 steel by 1600 W high power diode laser (HPDL) and 700 W Nd:YAG lasers were investigated in this present study. The distribution influence, and the lasers beam shape; Top-hat in the HPDL and Gaussian distribution in the Nd:YAG laser, have been studied on the geometrical dimensions, and micro-hardness in hardened area (i.e.; depth, width, and angle of entry of hardened profile), micro-hardness deviation (MHD) from the row steel in geometric dimensions, and the ferrite's percentage in hardened layer center. Microstructure evaluation of the laser hardened areas were performed by FE-SEM and optical microscopy. Based on the results, maximum hardness was created with the HPDL, and the geometrical dimension was more than the Nd:YAG laser. Also, MHD, and minor phase of ferrite in the HPDL laser surface hardening than the hardened layer in Nd:YAG laser, which is related to the higher laser absorption. Results show that, the hardened zone of HPDL is about 698 HV0.1 with 1.02 mm depth, while for Nd:YAG laser is about 698 HV0.1 with 0.98 mm depth. Comparing the results with the furnace hardening heat treatment (FHT) demonstrated that the hardness in diode laser and Nd:YAG laser hardening are 1.38 and 1.22 times of the hardness in FHT, respectively.
Bibliographical noteNOTICE: this is the author’s version of a work that was accepted for publication in Optik. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Optik, 204, (2020) DOI: 10.1016/j.ijleo.2019.163991
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- AISI 4130 low alloy carbon steel
- Beam shape
- Industrial lasers
- Laser surface treatment