Laser surface hardening of AISI 1055 steel in water submerged condition

Underwater laser hardening might produce better surface mechanical properties than conventional laser hardening in air due to additional cooling effect by water. However, it has not been studied in detail. This study investigates the effect of water layer on laser surface hardening of AISI 1055 stee...

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Bibliographic Details
Main Authors: Zhou, Wei, Zhou, Yu, Wu, Naien, Maharjan, Niroj
Other Authors: School of Mechanical and Aerospace Engineering
Format: Journal Article
Language:English
Published: 2019
Subjects:
Online Access:https://hdl.handle.net/10356/103473
http://hdl.handle.net/10220/48067
Description
Summary:Underwater laser hardening might produce better surface mechanical properties than conventional laser hardening in air due to additional cooling effect by water. However, it has not been studied in detail. This study investigates the effect of water layer on laser surface hardening of AISI 1055 steel. It is found that laser surface hardening is feasible with water layer up to 3 mm above the steel surface. A higher surface hardness is achieved during underwater processing. This is attributed to fast cooling by water which facilitates complete martensitic transformation. Nevertheless, the hardened area is smaller than that in conventional laser hardening in air due to attenuation of laser energy. Above 3 mm, the laser beam is severely attenuated due to formation of vapor plume. Furthermore, it is found that surface oxidation cannot be prevented completely even during underwater treatment, and the water movement results in random distribution of metal slag on the surface.