Title: Laser surface hardening: a review

Authors: P. Dinesh Babu, K.R. Balasubramanian, G. Buvanashekaran

Addresses: Department of Mechanical Engineering, National Institute of Technology, Tiruchirappalli-620015, India. ' Department of Mechanical Engineering, National Institute of Technology, Tiruchirappalli-620015, India. ' Welding Research Institute, Bharat Heavy Electricals Ltd., Tiruchirappalli-620014, India

Abstract: Laser surface hardening (LSH) is one of the most widely used surface hardening process which can be applied to almost the whole range of metallic materials in today|s applications. Laser beam is focused to the localised region for hardening the required portion of the material. High intensity laser radiation is involved for heating the surface of steel into the austenitic region. Steep temperature gradient arises, due to high rates of heat transformation that results in instant cooling by conduction. It causes the phase conversion from austenite to martensite without the need for external quenching. Among various types of lasers, CO2, Nd:YAG and diode lasers are the widely used lasers for hardening in industries. This review paper is a summary of the basic fundamentals of laser hardening, figuring some of its benefits compared with conventional hardening technique. The works published by various researchers by experimentation and by numerical approach are presented.

Keywords: laser surface hardening; LSH; microhardness; numerical analysis; wear; microstructure; Nd:YAG lasers; diode lasers; CO2 lasers.

DOI: 10.1504/IJSURFSE.2011.041398

International Journal of Surface Science and Engineering, 2011 Vol.5 No.2/3, pp.131 - 151

Available online: 21 Jul 2011 *

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