Journal Published Online: 25 August 2017
Volume 6, Issue 4

Study of Surface Properties of Plasma Nitrided Ferritic Stainless Steel 430L

CODEN: MPCACD

Abstract

Glow discharge plasma nitriding has been carried out on AISI 430L steel samples by varying mixture ratios of hydrogen to nitrogen (from 1∶4 to 4∶1) and process temperature (500°C–550°C). The treated samples were characterized using micro-hardness tester, X-ray diffractometer (XRD) and scanning electron microscope (SEM). The results show that the hardness has increased by a factor ranging from 4.79 to 5.71. The maximum hardness has been obtained for the case of process temperature 550°C, mixture ratio N2∶H2 = 1∶4, while the least hardness increase was seen for process temperature of 525°C, N2∶H2 = 4∶1. Case depth was also measured using an optical microscope. It ranged from 69 to 78 μm; minimum for process temperature 525°C, N2∶H2 = 4∶1, and maximum for process temperature 550°C, N2:H2 = 1∶4, respectively. XRD analysis showed the presence of Fe3 N, Fe4 N, and CrN when nitrogen was more than hydrogen, but only CrN were present when hydrogen was more than nitrogen in the gas mixture. The treated samples were also tested for dry wear using a pin-on-disk wear tester. The results show that weight loss of the untreated sample is from 3.8 to 5.7 times compared to treated samples under an applied load of 5 N and sliding distance of 25.4 km. The least weight loss was observed for process temperature of 550°C, mixture ratio N2∶H2 = 1∶4, and maximum weight loss was measured for process temperature of 525°C, mixture ratio N2∶H2 = 4∶1. SEM images show clear wear tracks for the untreated sample as compared to those that are barely visible for the treated samples.

Author Information

Gautam, D.
Gautam Buddha Univ., Greater Noida, Uttar Pradesh, India
Ganguli, B.
Inst. for Plasma Research (IPR), Bhat, Gandhinagar, India
Sharma, S.
Gautam Buddha Univ., Greater Noida, Uttar Pradesh, India
Pages: 13
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Stock #: MPC20160084
ISSN: 2379-1365
DOI: 10.1520/MPC20160084