Utilization of Color Metallography in Characterization of a Modified SAE 4118H Steel Submitted to Isothermal Treatments

Abstract:

A modified SAE 4118H steel was subjected to isothermal treatments between 700 °C and 400 oC every 50 °C range, with the intention of evaluating the decomposition of austenite at constant temperature. It was varied time of stay in the isothermal treatment between 15 and 28800 seconds depending on the treatment temperature. After each isothermal treatment and standard metallographic preparation, the samples were etched with color metallography reagents for revealing the microstructure obtained. At temperatures of 700oC to 550°C the steel showed microstructure composed of ferrite and pearlite. Between 500oC and 400°C bainitic microstructure was quickly formed. The reduction of treatment temperature provided finer microstructures, which increased the hardness of steel. With the use of color metallography reagents, excellent contrast for determining the volume fraction of microstructural constituents formed isothermally was obtained, helping the study of isothermal decomposition of austenite.

• Periodical: Materials Science Forum (Volume 805)
• Pages: 242-247
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.805.242
• Online since: September 2014
• Authors: Selauco Vurobi*, Thiago Ferreira de Andrade, Osvaldo Mitsuyuki Cintho
• Keywords: Color Metallography, Isothermal Treatments, Modified SAE 4118H Steel

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