S-Phase Layer Development on 316 LVM Using Low Temperature Hybrid Thermochemical Treatment Process
Mohd Shahriman Adenan1, Siti Umrah Zainal2, Esa Haruman3

1Mohd Shahriman Adenan*, Faculty of Mechanical, Universiti Teknologi MARA, Shah Alam, Selangor, Malaysia.
2Siti Umrah Zainal, Faculty of Mechanical, Universiti Teknologi MARA, Shah Alam, Selangor, Malaysia.
3Esa Haruman, Faculty of Engineering, Universitas Bakrie, Jakarta, Indonesia.
Manuscript received on September 23, 2019. | Revised Manuscript received on October 15, 2019. | Manuscript published on October 30, 2019. | PP: 5845-5849 | Volume-9 Issue-1, October 2019 | Retrieval Number: A3015109119/2019©BEIESP | DOI: 10.35940/ijeat.A3015.109119
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract: This investigation focuses on the improvement of surface properties of medical grade austenitic stainless steel (AISI 316LVM). The aim is to develop a homogenous supersaturated hard layer of expanded austenite (s-phase) at the surface of AISI 316LVM using low temperature hybrid thermochemical heat treatment process. The s-phase layer produced by this process is able to improve the surface properties of AISI 316LVM, overcoming its drawback of low surface hardness and wear resistance, without impairing the corrosion resistance of the steel. During the heat treatment process, ammonia (NH3) and methane (CH4) gasses were introduced into the furnace with temperatures of 425°C and 475°C, at 6 and 12 hours with gas composition of 75% of NH3, 10% of CH4, and 15% of Nitrogen (N2). Characterization on the microstructure showed the formation of the S-phase layer with variation of thickness according to parameters used. The S-phase formation was confirmed with phase analysis using XRD. Besides, the surface hardness also significantly increased from 210.9 HV to 1170.0 HV. In conclusion, low temperature hybrid heat treatment process is able to produce a homogenous hard s-phase layer.
Keywords: 316 LVM, Hybrid surface treatment, Ammonia, Methane, S-phase layer, Surface hardness.