Journal Published Online: 29 August 2017
Volume 6, Issue 4

Effect of Shot Peening Coverage on Surface Nanostructuring of 316L Stainless Steel and its Influence on Low Temperature Plasma-Nitriding

CODEN: MPCACD

Abstract

Air-blast shot peening (ABSP) is a cost effective and industrially viable technique to produce nanostructured surface layer on metallic materials. In the present study, 316L stainless steel samples were subjected to shot peening at different peening coverage, from conventional to severe peening. Nanocrystalline structure was observed on the sample surface after peening and mechanical twins; intersection of multidirectional twins producing rhombic blocks were observed in the subsurface layer. Peening process led to the formation of strain induced martensite (α‘), and its fraction was found to increase with the coverage. Depth of nanostructured layer and surface microhardness also increased with the increase in coverage, whereas surface roughness followed an opposite trend. Both peened and un-peened samples were subjected to plasma nitriding at 400°C for 4 h. Uniform and appreciably high case depth of about 45 μm was observed in severely pre-peened (1000 % coverage) sample after nitriding treatment. No precipitation of CrN was observed. This highlights the marked influence of severe shot peening as a pre-treatment for low temperature plasma nitriding of austenitic stainless steels.

Author Information

Jayalakshmi, M.
Dept. of Metallurgical and Materials Engineering, National Inst. of Technology Karnataka, Surathkal, Karnataka, India
Ramachandra Bhat, B.
Dept. of Chemistry, National Institute of Technology Karnataka, Surathkal, Karnataka, India
Udaya Bhat, K.
Dept. of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal, Karnataka, India
Pages: 10
Price: $25.00
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Details
Stock #: MPC20160079
ISSN: 2379-1365
DOI: 10.1520/MPC20160079