Eventos Anais de eventos
COBEF 2017
Congresso Brasileiro de Engenharia de Fabricação
CARACTERIZAÇÃO POR DRX EM AÇO CA6-NM REVENIDO E NITRETADO POR PLASMA A BAIXA TEMPERATURA
Submission Author:
Leonardo Luis Santos , PR
Co-Authors:
Rodrigo Perito Cardoso, Silvio Francisco Brunatto
Presenter: Leonardo Luis Santos
doi://10.26678/ABCM.COBEF2017.COF2017-0092
Abstract
The CA6-NM martensitic stainless steel is often utilized in hydraulic turbines, pumps, compressors and other applications. This is due its excellent combination of corrosion resistance and tenacity. Even so, thermochemical treatments are often used to attain improvements on its superficial properties, such as wear resistance and fatigue. In this case, the use of the plasma nitriding, realized by means of ionic bombardment, allow an alteration in the surface structure of the steel, resulting in a significant increase in hardness. Thus, this work aims to characterize by means of the technique of X-Ray Diffractometry the formed phases on the nitrided surface of the CA6-NM steel, tempered for different conditions, with an emphasis to the nitrogen expanded austenite formed during the plasma nitriding treatment. Therefore, samples on the dimension of 30 x 25 x 10 mm were air quenched starting at the temperature of 1000ºC for 30 min and, posteriorly, tempered at a vacuum furnace. The tempering temperature adopted was 620 ºC, for times of 1, 5, 10, 20 and 40 h, to obtain distinct quantities of the austenite phase dispersed on the martensitic matrix. After the thermic treatment, the samples were submitted to the process of plasma nitriding, at the temperature of 350 ºC, for a period of 24 h. In the thermochemical treatment of nitriding was evaluated the nitrogen potential as a austenitizing element, and the formation of iron nitrides due to the saturation of martensitic and austenite phases on the formed layer. In addition to the samples characterization with the X-Ray Diffractometry (XRD) technique, optic microscopy and determination of Vickers microhardness was also used. Analysis obtained by XRD indicate heavy evidences of the expansion of the austenite and martensite net parameters, due to the nitrogen diffusion.
Keywords
Austenite expanded by nitrogen; CA6-NM martensitic stainless Steel; Plasma nitriding at low temperature.
