Title: Metallurgical and tribological investigation of micro-scale fibre laser-based surface hardening

Authors: Yogesh R. Wagh; Santanu Paul; Neeraj Gupta; Ramesh K. Singh

Addresses: Department of Mechanical Engineering, Indian Institute of Technology Bombay, India ' Department of Mechanical Engineering, Indian Institute of Technology Bombay, India ' Department of Mechanical Engineering, Indian Institute of Technology Bombay, India ' Department of Mechanical Engineering, Indian Institute of Technology Bombay, India

Abstract: This work presents a comprehensive analysis of the mechanical, metallurgical and tribological responses of the various micro-scale laser hardened patterns of EN-8 steel at different process conditions. A 100 W continuous wave fibre laser with ~200-900 µm beam diameter was used for micro-scale hardening. EBSD was used to investigate the micro-structure and the hardness values were measured using micro hardness tester (Shimadzu-HMV). Additionally, to measure the tribological response, four different hardened patterns were analysed using the 'pin on disk setup' (DUCOM wear and friction monitor TR-20LE). The preliminary results revealed improved surface hardness values with increase in percentage overlap due to the formation of martensite. Furthermore, it was observed that the average wear rate of hardened specimen decreases by ~91% as compared to the unhardened specimen. The results revealed an inverse relationship between friction force and percent-hardened area, with minimum friction force obtained for a fully hardened pattern.

Keywords: laser hardening; fibre laser; EBSD; wear and friction force.

DOI: 10.1504/IJMMS.2018.092869

International Journal of Mechatronics and Manufacturing Systems, 2018 Vol.11 No.2/3, pp.120 - 134

Received: 29 Aug 2017
Accepted: 28 Nov 2017
Published online: 01 Jul 2018 *

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