PEARLITE TRANSFORMATION FROM FERRITE PHASE BY HIGH TEMPERATURE GAS NITRIDING OF DUPLEX STAINLESS STEEL

Niskan Etim Dan, Nurlianah Rashid, Patthi Hussain, Hamed Mohebbi and Norlaili Amir

  • Patthi Hussain

Abstract

PEARLITE TRANSFORMATION FROM FERRITE PHASE BY HIGH TEMPERATURE GAS NITRIDING OF DUPLEX STAINLESS STEEL

Niskan Etim Dan, Nurlianah Rashid, Patthi Hussain, Hamed Mohebbi and Norlaili Amir

Department of Mechanical Engineering, Universiti Teknologi PETRONAS, 32610 Bandar Seri Iskandar, Perak Darul Ridzuan, Malaysia

 

Abstract

 Duplex stainless steel has a dual existence of austenite and ferrite. Nitriding was conducted on duplex stainless steel at a temperature of 1100°C at various treatment times of 1h, 2.5h, 4.5h and 6h. Morphological study with scanning electron microscope, X-ray diffraction and optical microscope showed precipitation S phase at 4.5h and pearlite transformation at 6h from expanded austenite as a result of more nitrogen diffusion at ferrite phase. Hardness test was also conducted to investigate the effect of precipitates in respect to various times and it was observed that sample treated at 6h has the highest hardness value. XRD showed the precipitation of expanded austenite and precipitation of a new phase that is suggested to be pearlite which is responsible for the increase in hardness of the material. Subsequently, a hybrid layer was formed that enhanced the tribological properties of the heat treated DSS. This work has been able to show the precipitation of pearlite due to nitrogen at a high nitriding temperature with a corresponding treatment time of 6h.

Keywords: Pearlite transformation, gas nitriding and sensitization

ARTICLE INFO

Received 27th November 2017

Received in revised form 31st December 2017

Accepted 31st December 2017

*Corresponding author: Patthi Hussain

Tel. +6(05)3687158 e-mail: patthi_hussain@utp.edu.my

Malaysian Journal of Microscopy (2017) ISSN: 1823-7010 eISSN 2600-7444

Published
2017-12-31
Section
Original Research Articles