Plasma Nitrocarburizing of AISI 316L Austenitic Stainless Steel: a First Step for Treatment of Components with Complex Geometries

Abstract

The surfaces of AISI 316L austenitic stainless steel components with complex shapes and geometries can be subjected to extreme loads with intensive wear stress resulting a short lifetime. Low temperature active screen plasma nitrocarburizing (ASPNC) can be applied to form a thin duplex layer known as expanded austenite, improving the hardness and wear resistance with acceptable corrosion resistance. However, ASPNC of shaped components and components with different aspect ratios may yield non-uniform expanded austenite layer and/or reproducibility problems limiting their applications for specific cases. In this study, first, ASPNC of AISI 316L treated at different temperatures was investigated using active screen made of carbon-fibre reinforced carbon (CFC) to determine a reliable treatment temperature without CrN precipitation. In addition, several non-uniformity effects related to geometry and shape of structured samples were investigated during ASPNC treatment at different biased conditions. It was shown that in case of structured samples, a weak bias power at the samples was an essential process parameter to guarantee the formation of thick and homogenous expanded austenite layer while in non-biased conditions, thin and inhomogeneous expanded austenite is formed.

Pengaruh Nitrocarburizing Terhadap Kekerasan Dan Laju Korosi Pada Baja Tahan Karat Aisi 410

“…Penggunaan baja tahan karat salah satunya dibuat untuk menggantikan alat medis sebagai struktur dan fungsi bagian biologis [1]. Nitrocarburizing plasma telah banyak digunakan untuk meningkatkan kekerasan baja tahan karat tanpa mempengaruhi sifat ketahanan korosi yang baik [2].…”

The Interplay Effects between Feed-Gas Composition and Bias Plasma Condition during Active-Screen Plasma Nitrocarburizing with a Solid Carbon Source

“…Among the crucial treatment parameters in ASPNC, the feed-gas composition, treatment duration, treatment temperature and the level of plasma power applied at the workload, as well as at the AS, have great influences on the nitriding and the carburizing effects on the treated samples, and thus on the ability to tune the properties of the generated duplex-layer structure of the expanded austenite layer. Previously, several studies were conducted to separately optimize the treatment temperature [30], the level of bias plasma power [25,26] and the feed-gas composition [31] during the ASPNC treatment of AISI 316L with a CFC-AS to achieve a thick and pure expanded austenite layer with high surface hardness along with good corrosion resistance. However, due to the novelty of using solid-state carbon (such as CFC) as an AS material, the connection between the effects caused by both the feed-gas composition and the bias plasma power on the treatment environment and, consequently, on the material response has not yet been investigated to achieve tuneable surface properties of the resulting expanded austenite duplex layer using ASPNC with an CFC-AS.…”