USO DE ENSAIOS DE MICROESCLEROMETRIA INSTRUMENTADA NO ESTUDO DAS PROPRIEDADES DA AUSTENITA EXPANDIDA

• Published in: Tecnologia em metalurgia, materiais e mineração Vol. 12; no. 2; pp. 115 - 122
• Main Authors: Sato, Fernando Luis, Tschiptschin, André Paulo
• Format: Journal Article
• Language: Portuguese
• Published: Sao Paulo Associação Brasileira de Metalurgia, Materiais e Mineração 01.04.2015
• Subjects: Adhesion tests; Atmospheric models; Austenite; Austenitic stainless steels; Corrosion resistance; Direct current; Failure; Friction; Ion nitriding; Mechanical properties; Nitrogen; Passivity; Plasmas (physics); Stainless steel; Surface hardening; Thermal expansion; Tribology
• ISSN: 2176-1515; 2176-1523
• DOI: 10.4322/2176-1523.0827

Corrosion resistance and poor mechanical properties are both characteristics of AISI 316 austenitic stainless steel. Nitrogen supersaturated expanded austenite, or S-phase, promotes surface hardening of the alloy without the formation of undesirable that can reduce passivation properties. Mechanical characterization of this layer using instrumented microscratch tests gives an important set of empirical data useful for comprehension and modeling of tribological phenomena occurring in mechanical system. This work presents results from a series of instrumented microscratch tests performed on Low Temperature Plasma Nitrided (LTPN) AISI 316 stainless steel samples with an expanded austenite layer. The specimens were produced by 20 h active screen plasma nitriding treatment, done in direct current reactor at 400°C in an atmosphere containing three parts of nitrogen for one part of hydrogen (3N2:1H2). The reduced friction coefficient (< 0,1) between the indenter and the expanded austenite layer observed in the initial stage of scratch test and the absence of adhesive failure along the test are also discussed.