Title: Optimisation of gaseous nitriding process parameters for hard surface layer of duplex stainless steel

Authors: Md Abdul Maleque; Lailatul Harina; Norinsan Kamil Othman; Md Mustafizur Rahman

Addresses: Department of Manufacturing and Materials Engineering, Kuliyyah of Engineering, International Islamic University Malaysia, P.O. Box 10, 50728 Gombak, Kuala Lumpur, Malaysia ' Department of Manufacturing and Materials Engineering, Kuliyyah of Engineering, International Islamic University Malaysia, P.O. Box 10, 50728 Gombak, Kuala Lumpur, Malaysia ' Materials Science Program, School of Applied Physics, Faculty Science and Technology, National University of Malaysia, 43600 Bangi, Selangor, Malaysia ' Faculty of Mechanical Engineering, University Malaysia Pahang, 26600 Pekan, Pahang, Malaysia

Abstract: The optimisation for gaseous nitriding process parameters of duplex stainless steel was performed using Taguchi approach. The nitriding process parameters of temperature, time and gas mixture ratio of NH3 and N2 are considered as input parameters. Three responses are chosen which are surface hardness, wear weight loss and coefficient of friction. The optimum process parameters for surface hardness and coefficient of friction are similar with 550°C, 16 hour and 0.3 NH3/N2. The study revealed that temperature and time are the most significant factor influencing the responses of nitrided surface of DSS. The formation of hard surface layer contains expanded austenite with thickness layer until 135 μm and maximum hardness of 1,440 Hv. The hardness values produced five times greater than untreated DSS. The worn surface after wear test has improved with mild wear and smooth abrasion mark.

Keywords: optimisation; duplex stainless steel; DSS; Taguchi method; hard surface layer; nitriding.

DOI: 10.1504/IJMATEI.2019.101962

International Journal of Materials Engineering Innovation, 2019 Vol.10 No.3, pp.165 - 185

Received: 24 Sep 2018
Accepted: 03 Nov 2018

Published online: 28 Aug 2019 *

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